CH61 stifle

Question 1

• What is the shape of the medial condyle of the tibia compared to the lateral?

Answer 1

• Medial = oval
• Lateral = circular

Question 2

• What are the portions of the patella?

Answer 2

• Apex (distal) & Base (proximal)

Question 3

• What is the importance of the parapatellar firbocatilages?

Answer 3

• Prevent patellar luxation

Question 4

• What are the four sesamoid bones associated with the stifle?

Answer 4

• Two fabellae
• Popliteal = tendon of origin for the poploiteus m.
• Patella = largest sesamoid in body

Question 5

• How many articular surfaces are there in the stifle joint?

Answer 5

3
* Medial femoral condyle
* Lateral femoral condyle
* 3rd within femoral trochlea on the cranial surface

Question 6

• What is the attachment site for the CrCL and cranial meniscus ligaments?

Answer 6

• Cranial intercondylar area = oval depression, cr to intercondylar eminence

Question 7

• Where is the attachment site for the caudal meniscus ligament?

Answer 7

• Caudal intercondylar area = small depression cd. To the intercondylar eminence

Question 8

• Where is the attachment site of the caudal cruciate ligament?

Answer 8

• Popliteal notch of caudal aspect of tibia(separates the tibial condyles)

Question 9

• What 3 structures attach to the tibial tuberosity?

Answer 9

• Patellar ligament
• Biceps femoris
• Sartorius muscles

Question 10

• What are the 3 sesamoids of the stifle?

Answer 10

• Patella - largest
• Fabellae
• popliteal

Question 11

• What muscle groups do the fabella arise from?

Answer 11

• Lateral & medial heads of the gastronemius muscle

Question 12

• How many sacs form the stifle joint capsule, and where are there locations?

Answer 12

3 sacs
* Medial femorotib = divided into femeromeniscal + tibiomeniscal parts by menisci
* Lateral femorotibial = divided into femeoromeniscal + tibiomeniscal parts by menisci
* Femoropatellar

Question 13

• Where is the infrapatellar fat pad located?

Answer 13

• EXTRAsynovial but INTRA-articular

Question 14

• Which meniscotibial ligament attaches more cranial, the medial or lateral? How are they in reference to the cranial cruciate ligament attachment site?

Answer 14

• Medial is most cranial, cranial to the cranial cruciate ligament

Question 15

• What are differences in attachments of the caudal lateral meniscotibial and medial meniscotibial ligaments?

Answer 15

• Medial - attaches to caudal intercondyloid area of the tibial
• Lateral - attaches to the popliteal notch

Question 16

• What is the attachment site of the meniscofemoral ligament of the lateral meniscus?

Answer 16

• Intercondylar fossa of the femur

Question 17

• How are the cruciate ligaments classified?

Answer 17

• Intra-articular
• Extra-synovial

Question 18

• What are the ligaments and attachments sites of the medial meniscus?

Answer 18

Cranial meniscotibial ligament
- cranial intercondyloid fossa CRANIAL to the CrCl and intermeniscal ligament and LATERAL cranial meniscotibial ligament

Caudal meniscotibial ligament
- caudal intercondyloid fossa

Intermeniscal ligament → connect the cranial edges of the med & lat menisci

Question 19

• What are the ligaments and attachment sites of the lateral meniscus?

Answer 19

• Cranial mensicotibial ligament → cranial intercondyloid fossa
• Caudal mensicotibial ligament → politeal notch
• Intermeniscal ligament → cranial part of the cranial meniscotibial ligament
• Meniscofemoral ligament → the intercondylar fossa of the femurl

Question 20

• What are origin and attachment of the cranial cruciate ligament?

Answer 20

• Origin - caudomedial of lateral femoral condyle AND caudolateral par of intercondylar fossa of femur → cr/med/distal direciotin → cranial intercondyloid area of tibia

Question 21

• What are the 2 parts of the crcl, and which one is bigger?

Answer 21

• Caudolateral = LARGER
• Craniomedial = SMALLER

Question 22

• What is the origin/insertion of the caudal cruciate ligament?

Answer 22

• Lateral surface of medial femoral condyle → caudodistally → medial edge of popliteal notch of tibia
• Fibers spiral inward, abaxially at about 90 degrees

Question 23

• What is the main difference between cranial and caudal cruciate ligaments?

Answer 23

• Attachment sites
• Caudal Cruciate = larger than cranial

Question 24

• What structures is the medial collateral fused with?

Answer 24

• Medial joint capsule
• Medial meniscus

Question 25

• Why is the lateral meniscus not associated with the lateral meniscus and joint capsule?

Answer 25

• It passes over the tendon of origin of the popliteal m. and inserts on the fibular head

Question 26

• How does the shape of the meniscus distribute radial force when the joint is loaded?

Answer 26

• Circumferentailly arranged collagen fibers of tissue generate tensile stress which resists radial force • Tensile stress = hoop stress

Question 27

• What Ligament attaches the meniscus to the joint capsule at the medial meniscus?

Answer 27

• Coronary ligament

Question 28

• What structure is interposed between the lateral meniscus and lateral collateral and the joint capsule, preventing tight adherence of the two structures?

Answer 28

• Popliteal muscle

Question 29

• Why is the lateral meniscus less likely to be injured during movement?

Answer 29

• Lateral meniscus • No attachment to the joint capsule and LCL • Attached to the femur via the femoromeniscal ligament caudally • Attachment to the popliteal tendon along the lateral and caudal aspect of the groove • Medial meniscus • Attached to the tibia, joint capsule and MCL via the coronary ligament

Question 30

* What are primary collagen fibers in the meniscus?

Answer 30

- T1, fibrocartilage

Question 31

* What are the 3 layers of the meniscus composed of and what forces do they resist?

Answer 31

Superficial - * disorganized fibrils, good for low friction Deep → * inner ⅓: radial pattern, function in compression; also keep circumferential fibers together and resist longitudinal splitting Deep → * outer ⅔: circumferentially = function in tension

Question 32

• What is the biphasic theory regarding meniscus?

Answer 32

• Solid matrix phase + interstitial fluid phase • Load applied = solid phase • Shows elastic response • Circumferential collagen • Compressive load = carried by fluid phase • Acts like a rubber like material if loaded quickly or like a more stiff material if loaded slowly because viscous dissipation occurs • *depends on load rate

Question 33

* What are the 3 regions of blood supply to the meniscus?

Answer 33

* Red-red: peripheral 15-25% of the meniscus supplied by synovial fringe (Reason to repair tears in this zone) * Red-white = intermediate zone * White-white : axial

Question 34

• What arteries supply the perimeniscal capillary plexus via synovial reflection?

Answer 34

• Lateral and medial geniculate arteries

Question 35

• What is avg flexion and extension angles of stifle, and average ROM?

Answer 35

• Flexion - 41 • Extension - 162 • ROM - 121 (to 140)

Question 36

• Describe laxity of MCL and LCL in flexion, then extension?

Answer 36

• MCL/LCL TAUT in extension = minimal rotation of tibia as primary stablizers • CdMCL + LCL = LAX in flexion → allows lateral femoral condyle to displace caudally → internal rotation of the tibia

Question 37

• What limits varus and valgus in extension?

Answer 37

• Collateral ligaments

Question 38

• What limits varus and valgus at 90 deg flexion?

Answer 38

• All four ligaments limit valgus • CrCl, CdCl and LCL limit varus • Functions of the CrCl • Limit cranial translation • Limit hyperextension • Limit internal rotation with the CdCl

Question 39

* When is craniomedial band taut in relation to flexion and extension of the medial collateral, and when is caudolateral taut in relation to flexion and extension?

Answer 39

Craniomedial - taut in flexion AND extension - primary against cranial tibial translation Caudolateral - taut in extension, relaxed in flexion - secondary against cranial tibial translation

Question 40

• What is primary purpose of caudal cruciate ligament ?

Answer 40

• Restraint against cd tibial translation with respect to the femur • limits internal rotation • Limites hyperextension • Limit varus and valgus

Question 41

• When is cranial band taut in relation to flexion and extension, and when is caudal band taut in relation to flexion and extension, for the caudal cruciate?

Answer 41

• Cranial bnd - taut in flexion, relaxed in extension • Caudal band - taut in extension, relaxed in flexion

Question 42

• What is one of the main functions of the meniscus that when removed contributes to postop articular cartilage degeneration?

Answer 42

• Load bearing and force distribution, shock absorption, joint stability • Protect the articular cartilage by lowering the stress on the articular cartilage

Question 43

• How much load to the menisci bear

Answer 43

• 40-70% across the joint

Question 44

* By transecting the caudal meniscotibial ligament of the medial meniscus, what is the % increase in peak contact pressure and decrease in contact area?

Answer 44

* 140% inc in peak pressure & 50% reduced contact

Question 45

• Describe the relationship of the meniscus to load.

Answer 45

• As the meniscus is loaded the meniscus is extruded peripherally causing the circumferential collagen to elongate → hoop stress • This is countered by the coronal ligament attachment to the tibia, MCL and joint capsule

Question 46

• What fibers in the meniscus develop tensile hoop stress?

Answer 46

• Circumferential

Question 47

• What % radial width of the meniscus is required to allow hoop tension to develop?

Answer 47

• 25%

Question 48

• What is the role of the meniscus with relation to stability in the intact cruciate joint vs. non-intact?

Answer 48

• Intact joint → secondary role for joint stability • Cr defficient → caudal wedge of the meniscus prevents cranial translation

Question 49

• What occurs after caudal and full menisectomy?

Answer 49

• 50% decrease in contact area • 140% increase in pressure on the medial compartment • Pseudomeniscus formed from the synovial membrane in 3-6 mo • Progression of OA due to supraphysiologic load on cartilage • Kinematics of cruciate deficient stifle 1078

Question 50

• What happens at the stifle during gait in Cr deficient dog and how is this compensated for?

Answer 50

• Remains flexed • Increased extension of the tarsus and the hip to compensate

Question 51

• What happens to PVF (peak vertical force) after cruciate transection

Answer 51

• Normal = 70% of BW • 2 weeks post CrCl = 25% BW • 6 weeks post CrCl = 32% BW • 12 weeks post CrCl = 37% BW

Question 52

• What is mm cranial subluxation of the tibia respect to femur during stance in CCL deficient stifle?

Answer 52

• 8-12 mm

Question 53

• How much was peak cranial tibial translation increased compared with CCL intact condition, and how did this change 2 yr post -transection?

Answer 53

• 10 mm • 5 mm

Question 54

• What aids to reduce the cranial translation of the tibia during swing phase in CrCl?

Answer 54

• Meniscus acts like a spring at the end of stance phase • Important secondary stabilizer

Question 55

• What is the active model of the stifle (Slocum)?

Answer 55

• Stifle joint stability relies on synergy of: • Muscle forces that are responsible for flexion and extension • The cranial tibial thrust force • The passive restraints → CrCl and caudal pole of medial meniscus • Pull of stifle flexor muscles

Question 56

• What does the magnitude of cranial tibial thrust force depend on?

Answer 56

• Joint compression forces • Tibial plateau angle

Question 57

• How does the TPLO address this active model?

Answer 57

• Decreases the cranial tibial thrust force so that there synergism between the muscle forces and passive restraints by decreasing the tibial plateau

Question 58

• In the active model of the stifle, what counteracts normal cranial tibial thrust force?

Answer 58

• Caudal thigh muscles (active) • Cranial cruciate ligament and caudal pole of meniscus (passive)

Question 59

• What is magnitude cranial tibial thrust force dependent on in the active model of the stifle?

Answer 59

• Magnitude of the joint compressive force • Slope of the tibial plateau

Question 60

* What is the Tepic model of the stifle?

Answer 60

* Total joint force (joint reaction force) is parallel to the patellar ligament not the mechanical axis of the tibia (calcaneal tendon) * His model suggested that by making the patellar ligament and tibial plateau perpendicular you could stabilize the joint - TTA

Question 61

* What does the Slocum model propose total joint force is parallel to, and how does this compare to the Tepic model of joint force in the stifle?

Answer 61

* Slocum - parallel to the functional axis of the tibia (ie, common calcaneal tendon) * Tepic - weight bearing conditions, force applied to the paw is parallel to the patellar ligament

Question 62

• Based on Tepic’s model, what strategies should be employed to stabilize the stifle?

Answer 62

• Leveling plateau so that it is perpendicular to the patella ligament • Altering angle of patellar ligament so it is perpendicular to the plateau • [Image in source document] • Avulsion of the CrCl

Question 63

• What structure makes avulsion of the CCL in immature animals more common vs mid-substance tear?

Answer 63

• Sharpey’s fibers → attachment to the bone is stronger than the bone in young animals

Question 64

• Avulsion of attachment to femur or tibia is more common?

Answer 64

• Tibia >> femur

Question 65

* Treatment for avulsion

Answer 65

Epiphysiodesis * Insert screw into the center of the cranial intercondyloid area to cause closing of the cranial GP but the caudal continues to grow → leveling the TPA Reattachment of the avulsed ligament if there is sufficient bone - Reattach with divering k-wires or with looped wire that exits at the medial aspect of the tibia and it tied there

Question 66

• What is reported degree change following epiphysiodesis of cranial tibial plateau in dogs, and what is a common complication?

Answer 66

• 4-24 degree reduction in the plateau • Valgus deformity (3/22 joints)

Question 67

• What 3 forces can increase risk of acute traumatic rupture of the CCL?

Answer 67

• Excessive loading • Stifle hyperextension • Excessive internal rotation of the tibia

Question 68

• What kind of tear occurs with traumatic injury to the CrCl?

Answer 68

• Midsubstance mop end tear

Question 69

• What are 5 factors associated with CCL disease in dogs?

Answer 69

• Abnormal conformation • Gait • Increased plateau angle • Lack of fitness → inability to productively respond to mechanorecepotors in the CCL to “proctect” the CCLwith coordinate release of quads, and tightening of the hamstrings • +/- neutering

Question 70

• What is the protective mechanism of the cruciate that is enacted by the musculature of the pelvic limb?

Answer 70

• Stretch of the CrCl causes the mechanoreceptors to relax the quadriceps and flex the muscles of the caudal thigh (semis) to remove the strain on the ligament • Theory that dogs that are not fit or are overweight do not have this reflex

Question 71

• What are 2 distinct histo changes identified in ruptured CCL, and where in the ligament?

Answer 71

• Decreased fibroblast numbers in core region + lack of collagen fiber maintenance • Core region → normal in the epi-ligamentous region

Question 72

• What are 3 factors that may influence inability to bridge for torn CCL ligaments?

Answer 72

• Immune mediated degeneration • Acquired loss of blood supply in the midportion of the ligament • Smaller intercondylar notch width

Question 73

• What antibodies have been id’d in serum and synovial fluid that is associated with OA of the stifle?

Answer 73

• T1/T2 collagen antiboidies • Not associated with CCL specifically

Question 74

• What load per unit body weight does rottweiler CCL require compared to a racing greyhound?

Answer 74

• HALF vs a greyhound • Took half as much load to rupture in Rott vs. Greyhound

Question 75

• What are the 3 most common breeds to be affected by CCL?

Answer 75

• Rottie • Newfoundland • Staffie

Question 76

• What are the 3 most uncommon breeds affected by CCL?

Answer 76

• Doxie • Bassett hound • Old english sheepdog

Question 77

• What are 5 breeds more commonly affected when < 2 yrs?

Answer 77

• Neapolitan mastiff • Akita • Saint bernard • Rottie • Mastiff • Newfie • Chesapeake bay retriever • Lab

Question 78

• What age and sex are more likely to be affected?

Answer 78

• Females > males • neutered > unneutered • Small dogs < 22 kg more likely to be affected later in life

Question 79

• What is the risk for dogs rupturing contralateral CcL, and median time from first diagnosis? What factors are associated with contralateral tear?

Answer 79

• 22-54% • 947 d from time of original CCL • Factors - increasing age = protective , • NOT associated with increased risk in labs - • Weight, age TPA, sex,

Question 80

• What 2 diseases can elicit a positive sit test?

Answer 80

• Tarsal disease • Stifle disease -> CCL rupture

Question 81

• What structures minimize cranial drawer when the stifle is in full extension?

Answer 81

• Collateral ligaments taut in full extension = minimize cranial drawer

Question 82

* What is tolerated degree of translation for “puppy drawer”

Answer 82

* 3-5 mm * Will have an abrupt stop = CrCl * also for severely muscle wasted pelvic limbs in adults

Question 83

• Drawer in flexion, which band is torn and why?

Answer 83

• Craniomedial band - caudolateral taut in extension only, so would elicit drawer in flexion only

Question 84

• What is the PE finding if the caudolateral band is torn and the craniomedial is intact?

Answer 84

• No drawer sign because the craniomedial is taut in flexion and extension

Question 85

• Why does drawer test elicit translation of the cruciate ligament? Why does the tibial compression test?

Answer 85

• Drawer- craniocaudal translation by direct pressure • Compression - creates stifle joint compression by simulation the contraction of the gastro muscle = tibial compression= cranial translation

Question 86

• What is the earliest radiographic sign of CCL deficiency?

Answer 86

• Loss or effacement of the infrapatellar fat pad shadow by soft tissue opacity in the lateral view

Question 87

• What is a radiographic finding that is consistent with risk of bilateral disease?

Answer 87

• Effusion of the contralateral stifle associated with odds ratio of 13.4 for risk of development CCL disease in contralateral stifle within 1 yr • [Image in source document]

Question 88

• What is the sensitivity and specificity of US of the menisci?

Answer 88

• 90% • 92.9%

Question 89

• What MRI finding is correlated with naturally occurring stifle lameness, NOT necessary CCL?

Answer 89

• Bone bruise = traumatic microfracture that may occur without gross change to adjacent cortices or overlying cartilage

Question 90

• What is sens/spec of ultrasound for diagnosis of meniscal pathology?

Answer 90

• 90/92 • Meniscal Tears

Question 91

• What portion of dogs with CCL tear have radial tears of the lateral meniscus?

Answer 91

• 77% • Often on the free axial edge → sig. unknown

Question 92

• What is the incidence of meniscus tear with CCL tear

Answer 92

• 30-80% • 33% in largest retro

Question 93

• What circumstances are associated with isolated meniscus tear in dogs?

Answer 93

• Boxer breed • Working dog • In association with OCD lesion

Question 94

• What is the risk of latent/postliminary meniscal tears in dogs?

Answer 94

• 2.8-26.8% • Latent = right after surgery - will never improve • Postliminary = months after surgery usually within the first 6 mo

Question 95

• What are risk factors for post operative (latent vs postliminary) meniscus tears in dogs?

Answer 95

• Intact meniscus ( vs meniscus release vs meniscectomy at the time of surgery)

Question 96

• TTA

Answer 96

• 6x more likely than tight rope, • 3x more likely than TPLO • Inappropriate stabilization

Question 97

• What type of tear is most common in the medial meniscus vs lateral meniscus?

Answer 97

• Longitudinal tear of the caudal pole • Shear stress to longitudinal and radial fibers from entrapment during cranial tibial translation • Radial tears of lateral meniscus • Rotational and translational instability = pinching of cranial pole of lateral meniscus between lateral intercondylar tubercle and the lateral femoral condyle

Question 98

• What part of the meniscus is under the most force during extension? Flexion?

Answer 98

• Extension → cranial • Flexion → caudal

Question 99

• What component of the meniscus resists compression/tension less and fail first under excessive stress?

Answer 99

• proteoglycans have less resistance, weaker in compression/tension, and fail first • The tear will propagate between collagen fibers instead of across them • If stress continues the tear propagates perpendicular to the tensile stress causing the longitudinal tears

Question 100

• What are degenerative changes that can be identified in the meniscus early on in CCL pathology?

Answer 100

• Decreased GAG • Meniscus tissue fibrillation and tears

Question 101

• What was the sensitivity of exacerbation of lameness in a CCL-deficient dog for meniscus tear?

Answer 101

• 52%

Question 102

• What % of Postliminary tears presented with a meniscus click

Answer 102

• 27%

Question 103

• What is the sensitivity, specificity, and accuracy of meniscus click for meniscal injury?

Answer 103

• 50%, 90%, 80%

Question 104

• What is the sensitivity, specificity, and accuracy of meniscus click for meniscal injury WITH pain on flexion?

Answer 104

• 85%, 57%, 76%

Question 105

• What is likelihood of dogs with complete CCL tear to have medial meniscal dz than those with partial, and what was corresponding incidence ratio?

Answer 105

• 9.6x more likely in complete tear • 11:1 incidence ratio

Question 106

• What is incidence of meniscal mineralization in cats, and what are associated risk factors?

Answer 106

• 46% • Older age, lower weight, lower BCS

Question 107

• What portion of the meniscus is always mineralized?

Answer 107

• Cranial horn → correlated with severe OA in medial compartment

Question 108

• What was the sens/spec of high field MRI for id’d meniscus tears? What factors are important for improving diagnostic accuracy?

Answer 108

• 100/94, accuracy improved with size of joint • Also, low field MRI less accurate • Cannot see in dogs 7-10 kg or smaller

Question 109

• What does the normal and abnormal meniscus look like on MRI?

Answer 109

• Hypoattenuating in normal meniscus on T1W • Increased signal and heterogeneity when injured

Question 110

• What are 2 limitations that contribute to low sens/spec of ct arthrography for id’ing meniscus injuries?

Answer 110

• Lack of experience • Poor distribution of contrast in abnormal joints

Question 111

• What is the sen/sp of ultrasound?

Answer 111

• 90/93

Question 112

• By what magnitude does probing enhance sensitivity and specificity for meniscus disease in arthrotomy? Scope?

Answer 112

• 2.1-2.6 times (arthrotomy) • 8 times (scope)

Question 113

• What approach is better for meniscal evaluation in CrCl deficient vs. intact stifles?

Answer 113

• Caudomedial → CrCl intact • Craniomedial → CrCl defficient

Question 114

* Types of meniscus tears

Answer 114

Vertical * Parallel to collagen Longitudinal tear * If displaced becomes bucket handle tear Bucket handle tear * Type of longitudinal tear Flap or oblique tear * Usually start as a vertical tear but then breaks off as a flap and can become macerated Radial tear * More common in lateral meniscus * Inner edge toward outer edge like sunshine Horizontal tear * In the transverse plane * Shear off the top of the meniscus Complex tear * Multiple tears * Degenerative * Yellow and soft * Fibrillated

Question 115

• What are the 3 approaches to the stifle that can be performed to view the caudal pole of the medial meniscus?

Answer 115

• Craniolateral • Craniomedial • Caudomedial

Question 116

• Describe the caudomedial approach to the stifle.

Answer 116

• Medial parapatellar approach • Incise the cranial border of the caudal part of the sartorius and reflect the muscle • Transverse incision behind the medial collateral ligament

Question 117

• What is the ideal flexed angle of the stifle to view the meniscus?

Answer 117

• Flex 110-130 deg

Question 118

• What is the most important component of the meniscus for enabling hoop stress

Answer 118

• Peripheral rim - preserve when able

Question 119

• What should be preserved if possible during menisectomy?

Answer 119

• Peripheral rim • Hoop stress • Blood supply to red-red and red-white

Question 120

• What are 2 minimally invasive instruments used for partial meniscectomy?

Answer 120

• Motorized shaver - 3.5 mm for displaced, 2.5 mm for non-displaced tissue • Radiofrequency Tissue ablation wands - resect tissue, high risk of thermal damage to cartilage

Question 121

• What other instruments besides shavers can be used for menisectomy?

Answer 121

• Meniscus knives • Punches - piecemeal removal • Blade - #11 or #15, Bard-Parker blades, Beaver mini blades) • Radiofrequency Tissue ablation wands • Arthroscopic basket forceps • Arthroscopic scissors

Question 122

• What are the 3 types of menisectomies and what are their indications?

Answer 122

• Caudal Hemimenisectomy • Meniscotibial ligament to MCL • Bucket handle tears, complex tears, degenerative tears, peripheral detachments • Total Menisectomy • Not usually indicated • For tears that extend to most of the meniscus and cannot be preserved • Partial Menisectomy • Removing the torn part but preserving the peripheral rim • Vertical, bucket handle, radial, flap

Question 123

• What is the extent of the caudal or segmental hemimeniscectomy?

Answer 123

• Mid-body to transect nof caudal meniscotibial ligament • For complex and degenerative tears, peripheral detachmetns w/macerated portions or peripheral detachments that cannot be repaired

Question 124

• What is the extent of a total meniscectomy?

Answer 124

• Transection of cd/cr meniscotibial ligaments • Rare -

Question 125

• What is extent of a partial meniscectomy?

Answer 125

• Removal of a damaged axial section of meniscus while preserving cranial/caudal meniscotibial ligaments

Question 126

• What is the goal of the meniscus release?

Answer 126

• To move the meniscus caudolaterally and take it out of the way of the impingement between the medial femoral and tibial condyle

Question 127

• What are the 2 types of meniscus releases?

Answer 127

• Caudal • Central (mid-body)

Question 128

• What are the two techniques for mid-body release?

Answer 128

• Inside-outside • Need inserted through the joint capsule at the caudal edge of the MCL • The blade follows the angle of that needle 30 deg to sagittal plane • Outside-Inside • Blade from outside of the joint capsule • [Image in source document]

Question 129

• What is the likelihood of postliminary tears after TPLO on scope vs arthrotomy?

Answer 129

• Dogs 4x more likely to get postliminary tear after arthrotomy w/out release vs scope w/out release

Question 130

* When can a meniscus be repaired?

Answer 130

* When the tear is in the red-red zone

Question 131

• What is the preferred method of menisectomy if possible and why?

Answer 131

• Partial because it preserves the peripheral rim which contributes to hoop tension and force distribution

Question 132

• What is the difference in long term postop with or without meniscus?

Answer 132

• Dogs with meniscal release or menisectomy had decreased function and more OA at 3-5 yrs post-op • Surgical Stabilization

Question 133

• What are the the four extra-articular methods of stabilizing the stifle joint?

Answer 133

• Lateral fabellar suture • Tight Rope (Arthrex) • Swivel Lock (Arthrex) • Fibular head transposition

Question 134

* What is the tunnel location for tightrope and what needs to be protected?

Answer 134

* Femur → distal to fabella and 2mm cranial to caudal lateral femoral condyle * Tibia → caudal to LDE groove and 2mm distal to joint surface * Protect: LDE, MCL, caudal sartorius

Question 135

• Describe the process of lateral suture (DeAngelis)

Answer 135

• Suture around the lateral fabella - recommend proximal to fabella to get the origin of the lateral head of the gastroc • Suture under the patella and back from medial to lateral through a hole in the tibial tuberosity that is caudal and proximal to the insertion of the patellar tendon • Place limb in 100 deg flexion and tighten to eliminate cranial drawer and compression test

Question 136

• What are 4 methods of tensioning a lateral suture?

Answer 136

• Hand + square knot • Sliding knot • Self locking knot • Tensioning device

Question 137

• What are 4 methods of securing a lateral suture?

Answer 137

• Square knots • Sliding slip knot + series of square knots • Self locking knot + series of square knots • Metallic crimp

Question 138

• How does nylon leader line compare to other type of nylon line?

Answer 138

• Higher failure load and greater stiffness, less elongation, and recovers resting tensions to a greater degree, biologically inert and low bacterial adherence

Question 139

• How does 27 and 36 kg nylon leader line compare when secured with a metallic crimp tube vs square knot?

Answer 139

• Crimp better than square knots • lower loop elongation, higher load to failure, greater stiffness, and greater initial loop tension vs those secured with a square knot

Question 140

• What is the optimal size of monofilament leader line?

Answer 140

• At least equivalent to the weight of the patient

Question 141

* What is the estimated load applied to suture in a lateral suture construct?

Answer 141

- 120-600N

Question 142

• Indicate the most and least isometric points on this image.

Answer 142

• Isometric → maintains the same distance during flexion and extension • F1-T1 → least isometric • F2-T3 → most isometric • Require bone tunnels • [Image in source document]

Question 143

* What is the least isometric points of the femur/tibia for suture anchors?

Answer 143

T1->F1 * Caudal as possible on the femoral condyle at the level of the proximal pole of the fabella → tibial crest at patellar lig attachment

Question 144

* What is the most isometric pairs of points for suture anchorage?

Answer 144

F2-T3 * F2 - as caudal as possible on the femoral condyle at the level of the distal pole of the fabella paired with caudal wall of the extensor groove of the tibia * T3 - cd wall of extensor groove of the tibia

Question 145

• In a radiographic analysis, what was the most ideal femoral point paired with which tibial point?

Answer 145

• Caudal edge of the lateral femoral condyle adjacent to distal pole of the fabella → adjacent to the extensor groove and tibial attachment of the patellar ligament

Question 146

• What is the infection and complication rate of lateral fabellar suture?

Answer 146

• Infection 4.6% • Complication 17.4% • Peroneal nerve deficits • Suture pulled through gastroc • Incision complications

Question 147

• How does lateral suture compare to TPLO?

Answer 147

• PVF was 6-11% higher in TPLO at 12 mo post op → better kinematic and owner satisfaction in TPLO • Achieve normal limb function faster in TPLO vs. suture

Question 148

• What is the tight rope technique and what suture and points are used?

Answer 148

• Bone tunnels at F2-T3 • Fiberwire tape (flat polyblend suture) - no give • Secured with buttons • 6 mo outcome no difference to TPLO • More cycle to failure than lateral suture • [Image in source document]

Question 149

* What is the swivel lock (arthrex) technique?

Answer 149

* Headless bone anchors in F2-T3 * Polyblend suture tape (fiberTape) * Complications 7.3% * Less likely to place in joint because no bone tunnels * No creep because no knots

Question 150

• In mechanical testing of loops of nylon vs polyethylene cord vs polyethylene tape secured in bone tunnels vs anchor, which construct were the only one for which creep was not significantly different than the corresponding isolated prosthetic loops?

Answer 150

• Polyethylene tape + bone anchor

Question 151

• How did symmetry indices for PVF and VI compare between lateral suture and TPLO at 6 amd 12 mo post op?

Answer 151

• TPLO no different than control at 6 and 12 mo • Lateral suture sig. Different than control at all time points • Concl: TPLO had better and faster recovery and returned to normal at 1 yr post op and lateral suture did not

Question 152

• What is the difference in outcome between dogs with low TPA and high TPA?

Answer 152

• None, TPA did not have affect on outcome for suture method

Question 153

• What was the difference in outcome between dogs that received rehab and those that did not for suture method?

Answer 153

• At 6 mo the pelvic limbs in the dogs that had rehab was not different than the normal limb but in the dogs that did not it was sig. Different • Rehab means rapid return to function

Question 154

• What is the postliminary tear reported in dogs with meniscal release + lateral suture, vs no meniscus release?

Answer 154

• 0% for release • 15.2% in dogs without release

Question 155

• What factors are associated with increased risk of complications with lateral suture?

Answer 155

• High body weight and young age at time of surgery

Question 156

• What is the infection rate for suture repair?

Answer 156

• 4.2%

Question 157

• What is the alternative to suture techniques for extracapsular repair and how is it performed?

Answer 157

• Fibular head transposition • The fibular head is dissected from the location on the tibia preserving the peroneus longus m. attachment and is repositioning cranially using a pin into the head and a figure of eight wire from the tibial tuberosity around the fibular head

Question 158

• What were the postliminary tear rates at 4 mo post op fibular head transposition? 10 mo?

Answer 158

• 25% at 4 mo, 50% at 10 mo

Question 159

• What is the biomechanical function of fibular head transposition in relation to a CCL deficient joint?

Answer 159

• Prevent cranial drawer movement and min. Internal rotation of the tibia

Question 160

• What are common complications associated with fibular head transposition?

Answer 160

• LCL tear • Fibular head fracture • Ost op instability • seroma

Question 161

• What was identified in cohort of patients undergoing fibular head transposition surgery 3 wks pst op

Answer 161

• LCL elongation in all dogs for which it was evaluated • Intracapsular techniques

Question 162

• What are the types of intra-articular techniques used for reconstruction of the CrCl?

Answer 162

• Allografts • Xenografts • Autografts • Synthetic

Question 163

• How long does revascularization and remodeling take grafts for CCL recon?

Answer 163

• 20 wks

Question 164

• What is the process of graft remodeling?

Answer 164

• Inflammation → graft necrosis → revascularization → cell repopulation → remodeling

Question 165

• What process leads to initial weakening of the CCL graft?

Answer 165

• Inflammation and necrosis of the transplanted ligament

Question 166

* What are intra-articular reconstruction techniques (4)

Answer 166

* Graft - autogenous, allograft, xenograft * Synthetic prosthesis - dacron, silk * Graft + augmentation device (LAD = ligament augmentation device) * LAD - protects graft during early periods of graft incorporation when it is weakest * Scaffold= allow/promote tissue ingrowth because of porous structure

Question 167

• What xenografts have been used in the dog?

Answer 167

• Bovine • Porcine patellar ligament

Question 168

• What is the biggest issue with xenografts and how is this overcome?

Answer 168

• Inflammatory response • Gluteraldehyde treatment to decrease rate of resorption

Question 169

• What is ligamentization?

Answer 169

• Inflammation causes fibroblast necrosis which leads to fibroblast infiltration along the collagen scaffold and secretion of new collagen during revascularization resulting in a new ligament

Question 170

• What allografts have been used successfully in the dog?

Answer 170

• Patellar ligament • Fascia lata

Question 171

• What are 3 different types of CCL autografts?

Answer 171

• Bone -patellar ligament-bone (not described in dogs) • Hamstring tendon (ST and gracilis)- not reported in dogs • Quad femoris muscle tendon = “over the top” placement in dogs

Question 172

• What is the over-the -top procedure for autografts in the dog?

Answer 172

• Maintain the attachment of the patellar ligament to the tibial tuberosity • Take the patellar tendon graft through the joint and attach it to the caudal femur

Question 173

• What is the proposed “weak link” of the patellar ligament graft in the “over the top” method in dogs?

Answer 173

• The need for the soft tissue to heal to bone at the attachment of the graft on the femur(from origin on tibial tuberosity → intra-articular → over the top of the lateral femoral condyle

Question 174

• What are the 3 categories of synthetic grafts?

Answer 174

• Permanent → prostheses • Augmentation • Scaffolds

Question 175

* What are 4 types of synthetic graft for CCL?

Answer 175

* Dacron * Gore Tex * Carbon FIber * PTFE

Question 176

• What is a common downside to synthetic prosthetic CCL? What was a major complication of Gore Tex synthetic graft?

Answer 176

• Creep • Mechanical fatigue led to swear debris = synovial reaction from particulates

Question 177

• What is augmentation?

Answer 177

• Used to protect the graft during its initial reincorporation • Kennedy ligament • Polypropalene ribbon • Did not have the strength as the implanted graft • Failed

Question 178

* What are scaffolds?

Answer 178

* Type of prosthesis that allowed or induced tissue ingrowth * The scaffold maintains strength while the neoligament is being formed then gradually breaks down and loads the neoligamnet * LARS * Silk * Leeds-Keio

Question 179

• What biomaterial has been successfully used in scaffold formation?

Answer 179

• Silk → strong, well tolerated by body, and promotes ingrowth

Question 180

• Describe the over-the-top procedure.

Answer 180

• Harves patellar tendon still attached to the tibial tuberosity • Pull through the joint • Attach to the lateral shaft of the femur

Question 181

• Describe the attachment of synthetic graft.

Answer 181

• Bone tunnel at the cranial intercondylar region • Pull through the bone and through the joint • Attach to the femur at the site of the gastrocnemius tendon • Screws and washer or belt-loop technique

Question 182

• When passing an “over the top” graft in a canine stifle, what intra-articular structure must be appropriately prepared to prevent impingement?

Answer 182

• Intercondylar notch - remove osteophytes

Question 183

* How is the graft passed through the joint?

Answer 183

* Preplaced hemostat in the intercondylar notch via lateral arthrotomy and dissection through the attachment of the gastrocnemius * Pull the graft through * Pull the graft under the intermeniscal ligament (under-and-over)

Question 184

• What are 2 methods of securing a patellar graft to the femoral condyle?

Answer 184

• Tie suture attached to graft around a screw in the distal femoral diaphysis • Avoids pulling graft around the corner • Wrap fascia around the screw and tighten w/spiked washer to entrap suture/fascia

Question 185

• How long should the patellar ligament graft be?

Answer 185

• 1.5x patella-tibial tuberosity distance

Question 186

• What are 2 methods of securing the patellar ligament graft to the tibia?

Answer 186

• Leaving tibia attachment in place and only mobilize proximal aspect • Patellar graft harvested with segment of bone at distal extent → oblique bone tunnel, and graft pulled through then following tensioning of graft, tibial bone block is secured with an interference screw

Question 187

• What are 2 methods of securing a synthetic graft to the tibia/femur?

Answer 187

• Screw +/- spiked washer (if preformed eye loop present) • 18 g wire in a belt loop fashion

Question 188

• What is considered the best method of fixing grafts to bone, and why?

Answer 188

• Interference screw to bone block → doesnt damage soft tissue of graft

Question 189

• What are the reported complications with grafts?

Answer 189

• Persistent laxity • Fracture of the tibial tuberosity with percurement of the graft • Fx of the patella

Question 190

• What is the bungee effect?

Answer 190

• Movement of the graft in line with the bone tunnel • Reduces success of the bony incorporation

Question 191

* What are the 6 osteotomies for stifle joint stabilization?

Answer 191

- CTCWO - Cranial Tibial Closing Wedge Osteotomy - TPLO - TPLO, CCWO - TTA - TTO - Modified Maquet

Question 192

• What is the basis for CTCWO?

Answer 192

• Slocum model that cranial translation is caused by the tibial slope • Magnitude of translation is comparable to magnitude of the TPA

Question 192

• In a study evaluating CTCWO, at what TPA did they find stifle stability, and at what angle did they see caudal tibial subluxation occur?

Answer 192

• TPA+ 6 = stable • TPA +7.5 or greater = caudal subluxation

Question 193

• What is the desired final TPA angle for CTWO?

Answer 193

• 4-6 deg

Question 194

• What are 3 methods of pre-operative planning for wedge in order to optimize lowering of the tibial plateau angle

Answer 194

• Measure TPA, and wedge should be the TPA -5 • Measure TPA, and the wedge should be TPA + 5 or + 7.5 • Align cranial cortices + move proximal → more likely to end up with TPA of 6

Question 195

• What is the outcome of tibial shortening on patella position and joint kinematics for CTCWO?

Answer 195

• Patella baja → stifle hyperextension • stifle/tarsus hyperextension during swing phase, normal in stance phase

Question 196

• What was the most common catastrophic complication of CTCWO that required re-operation?

Answer 196

• Catastrophic tibial fx, requiring multiple plates

Question 197

* What other two procedures can CTCWO be combined with?

Answer 197

- TPLO, lat suture

Question 198

• What osteotomy is the only osteotomy that can be performed on dogs with open growth plates?

Answer 198

• CTCWO → in dogs with open plates, that are too old for epiphysiodesis

Question 199

• What other orthopedic abnormality can CTCWO treat?

Answer 199

• Patella alta → wedge brings the attachment to the patellar tendon lower on the tibia

Question 200

• What are disadvantages of the CTCWO?

Answer 200

• Variability of post op TPA • Shortening of tibia • Patella baja • +/-Craniocaudal angulation of tibia from longitudinal tibial axis shift

Question 201

• What are the advantages of CTCWO

Answer 201

• Can be performed in young dogs with open growth plates • Can correct very steep slopes • Correct patella alta • No special equipment

Question 202

• During creation of a wedge for the CTCWO, what can be the outcome of an inadvertent biplanar wedge (ie, osteotomies from medial->lateral fail to remain parallel)

Answer 202

• Varus or valgus deformity

Question 203

* What are 3 plates commonly used for CTCWO?

Answer 203

- LCP, DCP, T plate

Question 204

* What can be used to help with alignment intraop in CTCWO?

Answer 204

* TPLO Jig

Question 205

• What happens when leveling to a TPA less than 6.5 deg in TPLO?

Answer 205

• Caudal subluxation • Shown that the caudal cruciate begins to degenerate in CrCl deficient stifles and excess tension on the Cd cruciate could cause further damage to this ligament

Question 206

• What happens to the femoral contact area on the tibial plateau in stance following TPLO?

Answer 206

• More caudal than normal

Question 207

• What forces does a TPLO neutralize, and which forces are not addressed by this surgery?

Answer 207

• Cranial subluxation • Not addressed- Internal rotation or hyperextension

Question 208

• What measurements are made on MedLat rads to determine the TPA?

Answer 208

• Mechanical axis • Joint orientation lines • TPA = mCdPTA

Question 209

• What is assessed on mediolateral rads for TPLO planning

Answer 209

• Measure plateau angle • Determine saw blade size

Question 210

• Identify appropriate osteotomy location

Answer 210

• Quantify magnitude of required TPLO • Confirm rotation is safe

Question 211

• What is assessed on caudocranial rads for TPLO planning?

Answer 211

• Angular rotation deformities • Quantify tibial alignment in the frontal plane w/proximal and distal joint orientation lines → mMPTA and mMDTA • ID fibular head with respect to joint surface for intra-op reference

Question 212

• What are the mean mMPTA and mMDTA values, and if frontal plane alignment varies from these what should be he outcome

Answer 212

• mMPTA 93, mMDTA 95 • Correct during TPLO

Question 213

• What defines the tibial plateau axis?

Answer 213

• Line connecting cranial and caudal extent of the medial tibial condyle • Synonymous with the proximal tibial joint orientation line in the sagittal plane

Question 214

• What defines the mechanical axis of the tibial in the sagittal plane, ie the long axis of the tibia?

Answer 214

• Line drawn between the point dividing the intercondylar tubercles of the tibia, and the center of rotation of the talus

Question 215

• How is the tibial plateau angle measured?

Answer 215

• Plateau angle measured at the intersection of the tibial plateau axis and the tibial long axis with reference to a line perpendicular to the tibial long axis

Question 216

• What is intra and interobserver variability for TPA measurements, and what was associated with significant differences in TPA between observers?

Answer 216

• Interobserver - 3.4 degrees • Intraobserver - 4.8-6 degrees • Experienced vs inexperienced = sig different

Question 217

• Where should the center of rotation of the osteotomy for accurate plateau leveling, and what occurs to the intercondylar tubercles as a result?

Answer 217

• Rotation of proximal segment should occur at the intersection of the tibial plateau and the tibial long axis lines → accurate leveling (center point, from cranial to caudal, of the articular surface of the medial condyle) • Slight translation of the intercondylar tubercles

Question 218

• What is D1? What is D2?

Answer 218

• D1 - measured as a line perpendicular to the cr border of the tibia • Distance from the patellar ligament attachment to the osteotomy • D2- measured along cranioprox. Border of the tibia • line from patellar lig attachment to where osteotomy exits tibia

Question 219

• When comparing the accuracy of the osteotomy using D1,2 and D1,2,3 what was found?

Answer 219

• No difference • D3 is the measurement from the patellar insertion to the exit of the blade at the caudal aspect of the tibia

Question 220

• What 3 structures constrain rotation of the proximal tibial plateau segment?

Answer 220

• Tibiofibular articulation • Proximal jig pin • Center of osteotomy

Question 221

• What aides in rotation?

Answer 221

• Jig pin 3-4mm distal to the tibial plateau surface • Osteotomy centered over the tibial plateau and tibial long axis intersection • Fibular head close to both these points

Question 222

• What does using jig w/saw guide improve in the TPLO (2)?

Answer 222

• More accurate placement of osteotomy • More accurate leveling of TPLO

Question 223

• What was jigless TPLO associated with (3)?

Answer 223

• 15 degrees craniolateral deviation of osteotomy • Increased risk of fibular fx • Increased risk of fixation failure

Question 224

• What does measuring rotation distance diagonally across the osteotomy lead to?

Answer 224

• Underrotation

Question 225

• What does alignment of the cortices lead to when rotated? What is to be expected at the osteotomy?

Answer 225

• Realignment of the cortices causes angular and rotational deformity • There should be a medial to lateral step after rotation

Question 226

• How is modest to moderate varus corrected with TPLO?

Answer 226

• Distal jig ARM slides medially, ie away from the tibia → push the distal tibia away

Question 227

• How is modest to moderate valgus corrected with TPLO?

Answer 227

• Distal jig ARM slides laterally, ie towards the tibia → pulls the distal tibia in medially

Question 228

• How is modest to moderate torsion corrected with TPLO?

Answer 228

• Bending distal jig pin in the frontal plane • Convex is cranial = external torsion to correct internal torsion • Concave is cranial = internal torsion to correct external torsion

Question 229

• What was the post-op range in TPA tolerated by dogs, if paired with meniscus surgery?

Answer 229

• 0-14 degrees

Question 230

• What is the reported complication rate with TPLO?

Answer 230

• 18-28%

Question 231

• What was the major, minor, and intraop complications in TPLO w/pre-contoured LCP plates + experienced surgeons?

Answer 231

• Intra op - 7% • Minor - 5.4% • Major - 0

Question 232

• What is the cause of major hemorrhage in the TPLO?

Answer 232

• Cranial tibial artery

Question 233

• Bilateral single stage TPLO is associated with what complication?

Answer 233

• Increased risk of complications 20-40% • 8.5-9.6x increased risk of tibial tuberosity fracture

Question 234

• What is the average change in TPA over the course of healing?

Answer 234

• Rock back caused by movement along the osteotomy site • 1.5 +/- 2.2 • Locking plate = less change

Question 235

• What 2 factors are associated with higher risk of patellar ligament thickening?

Answer 235

• Lower post op TPA (<6) • Greater body weight • Causes stress on the patellar ligament

Question 236

• What are 3 (other)factors that are associated with patellar ligament thickening?

Answer 236

• Cranially positioned osteotomy • Decreasing the distance between the the attachment of the patellar lig anf femoral condyles causes strain on the ligament • Tibial tuberosity fracture • Partially intact CCL + cranial positioned osteotomy

Question 237

• What are the grades of patellar ligament thickening? (3)

Answer 237

• 0= mild thickening, up to double of normal pre-op ligament • 1 = 6-11 mm thickness • 2 = >12 mm, or no identifiable borders

Question 238

• What are factors that have historically been associated with development of post-op TPLO neoplasia?

Answer 238

• Cast stainless steel plates that erroded • Metal alloy • Electrolysis between dissimilar metals in an implant • Tissue damage from sx/trauma • Altered cell activity from delayed union/nonunion/infection • Corrosion

Question 239

• What are 3 indications for combined TPLO/CCWO

Answer 239

• Manage excessive TPA ie > 34 degrees when a radius of 24mm is used for the blade

Question 240

• When rotation past insertion of the patellar lig. Is required

Answer 240

• Varus or valgus deformity

Question 241

• How is CCWO planned?

Answer 241

• Measure the safe amount of rotation by measuring the distance between the TPA and the patellar insertion • Examine the TPLO chart to see what that relates to • Decide the deg of closing wedge • TPA - closing wedge deg = new TPA

Question 242

• In a biplanar cranial closing tibial wedge ostectomy paired with TPLO, should angled osteotomy be performed on the proximal or distal arm of the osteotomy?

Answer 242

• Distal, prevent angle from entering TPLO

Question 243

• What are 3 techniques to aid in performing a biplanar osteotomy when doing a combined TPLO/CCWO?

Answer 243

• Bend distal jig pin to the angle of correction required = reference for saw angulation • K-wire inserted into tibia → betn to desired angle • Insert 2 jig pins parallel to proximal to tibial articular surface, and one jig pin distal, parallel to the tarsocrural joint • Perform proximal osteotomy parallel to the two pins, distal parallel to the distal pin, and then jig can be articulated with the third jig pin = reduction after osteotomy

Question 244

• How is Valgus correction performed with TPLO/CCWO?

Answer 244

• Coplanar medial closing wedge osteotomy

Question 245

• How is torsional correction performed with TPLO/CCWO?

Answer 245

• Rotation at the level of a single osteotomy if there is no varus or valgus

Question 246

• How is patella alta corrected with TPLO/CCWO?

Answer 246

• The amount the patella is moved is equivalent to the cranial cortex that is being removed

Question 247

• How is the TPLO/CCWO performed? Which osteotomy is performed first? What is the method of fixation?

Answer 247

• Radial osteotomy performed half way • Mark the CCWO • Can use the calculation method → length of the first arm to calculate the location of the second arm • Can use measuring device intra-op • Cut the radial osteotomy and place pins from patellar attachment on tibial tuberosity to segment - pins are left in • Cut the CCWO and reduce with pins • Apply TB to closing wedge • Apply bone plate in compression

Question 248

• What is the location with the slowest healing in the TPLO CCWO?

Answer 248

• The CCWO is the slowest healing

Question 249

• What are augmentation techniques for fixation?

Answer 249

• Additional bone plate in patients > 30 kg • 2.4 - 2.7 straight bone plate

Question 250

• What is the biomechanical theory behind the TTA?

Answer 250

• Nisell knee in humans and Montavon and Tepic (canine) • Joint force is parallel to the patellar tendon and cranial and caudal tibiofemoral shear is based on the knee in flexion angle • Cross-over point → point where the shear forces are neutral • Cross over point dependent on the angle between the TPA and the patellar tendon

Question 251

• What is the goal of TTA?

Answer 251

• To move the Tibial tuberosity cranially enough to make the patellar tendon angle 90 or less during extension to obtain neutral or caudally directed shear forces

Question 252

• What is the standard position of a mediolateral radiograph for TTA planning?

Answer 252

• Almost fully extended, stifle at 135, centered on the joint, no cr translation

Question 253

• What are 2 methods of preop measuring for TTA?

Answer 253

• Common tangent method (PTA^CT) • *less variation reported • Vs the PTA - TPA

Question 254

• What is PTA^CT and how is it measured?

Answer 254

• Intersecting line between a circle around the femoral condyles and a circle around the tibial plateau • This line is used to determine how much the tibia will need to be advanced to be perpendicular to this line • This is used instead of TPA because TPA had too much variation in anatomy • [Image in source document]

Question 255

• What is the positioning and radiograph needed to measure for TTA?

Answer 255

• Orthogonal views with stifle extended to 135 standing angle • Sitfle cannot be in drawer

Question 256

• What is the biomechanical justification for TTA?

Answer 256

• Neutralize the cranial tibial thrust force by frontal plane osteotomy of the tibial crest to advance the patellar ligament perpendicular to the common tangent of the femoral and tibial contact points

Question 257

• How is the craniomedial tibia exposed?

Answer 257

• Incision of the caudal belly of sartorius, aponeurosis of gracilis and semitendinosus insertions

Question 258

• Where should the cage be placed in TTA?

Answer 258

• 2-3 mm from the proximal tibial bone margin

Question 259

• How far proximal tshould the osteotomy begin relative to the proximal screw in the tibial shaft to avoid stress riser?

Answer 259

• 1 cm

Question 260

• What are the modified types of TTA and what is their modification?

Answer 260

• Modified Maquet, TTA-rapid, TTA-2 • Cage only and osteotomy length depends on the size of the cage

Question 261

• What is the overall complication rate of TTA?

Answer 261

• 19-50%

Question 262

• What were the most common complications reported with TTA?

Answer 262

• Fracture of the TT • Postliminary meniscal tears • Patellar luxation • Fx of the tibia

Question 263

• What is the reported outcome?

Answer 263

• Good to excellent function in 90% dogs

Question 264

• What are the most common surgical technique errors?

Answer 264

• TT piece too small • Cut too low → should be 1cm proximal to the first screw • Rotation of the TT → patellar luxation • Not allowing the proximal shift of the TT with advancement = patella too low • Forks too far from leading edge so the cage is not well secured • Distal end of the plate is off of the shaft

Question 265

• How is the cage positioned?

Answer 265

• Wider part is proximal

Question 266

• What complication of TTA leads to increased risk of patellar luxation, and what are the 2 reasons for this intra-operatively?

Answer 266

• Malposition of the tibial tuberosity in the frontal plane • Angled osteotomy • Improperly contoured plate = translation

Question 267

• What should be considered during plate selection?

Answer 267

• The location of the patellar tendon attachment site • Low = shorter/lower plate • High = longer plate

Question 268

• What is the risk of a low patellar ligament attachment site with TTA?

Answer 268

• Low attachment site = smaller tibial tuberosity segment = less buttress support for the cage because it is right next to the attachment and possibly treater forces that are distributed = possibly greater risks of fracture

Question 269

• What is the recommended max TPA and max advancement distance?

Answer 269

• Max TPA 30 → 25 is recommended also • 15 mm → largest cage there is • Steeper TPA requires more advancement

Question 270

• What is a technique for allowing additional advancement of the tuberosity?

Answer 270

• Transposing the cage distally causes more advancement • can put tuberosity proximal to the cage at risk of fracture

Question 271

• What is the downside for performing TTA with high (>30) TPA)?

Answer 271

• High TPA puts stifle in relative hyperextension → altered angle of the tibial plateau • Can achieve PTA of 90, but don't address the abnormal stifle position, and allow persistence of tibiofemoral shear

Question 272

• Can TTA be used to correct torsion, varus or valgus?

Answer 272

• NO - need medial or lateral wedges for that

Question 273

• What procedure can be combined with TTA to address patellar luxation, and how should the cage be modified?

Answer 273

• TTT - contour the plate to shift the bone • Caudall ear of the cage should be slightly recessed into proximal tibia,or cranial ear elevated above the surface of the tibia (For medial)

Question 274

• What is the goal of the TTO?

Answer 274

• Reduce TPA → wedge ostectomy • Reduce patellar tendon angle to 90 degrees → partial frontal plane osteotomy of the tibial tuberosity

Question 275

• What is the angle of the wedge osteotomy performed in a TTO?

Answer 275

• ⅔ of the angle between the patellar ligament and a line perpendicular to the tibial plateau slope • Calculation = WA = 0.6 x CA + 7.3 • CA = angle of correction of the patellar tendon angle needed to achive 90 degrees

Question 276

• What was the incidence of cranial cortex fracture at the level of the distal tibial tuberosity osteotomy on post op rads?

Answer 276

• 21% • Associated with higher risk of post op tibial crest fracture

Question 277

• What was the risk of intraoperative tibial tuber fracture requiring tension band fixation?

Answer 277

• 23% • Most common comp

Question 278

• What are 2 methods that can be used to avoid overdoing the wedge ostectomy leading to TPA < 0 degrees in a TTO?

Answer 278

• Wedge angle = TPA - 5 (if TPA minus calculated wedge angle is <0) , or TPA - 12 (if preop patellar angle close to 90 and only small correct needed)

Question 279

• What is the primary function of the CdCL, and what does it aid the CCL in as well in terms of limiting forces?

Answer 279

• Primary stabilizer vs cd tibial translation, • and functions with CCL to limit internal rotation and hyperextension

Question 280

* What concurrent tissues are often injured with the CdCL?

Answer 280

MCL, CrCL

Question 281

• What is a PE finding to diagnose CdCl rupture?

Answer 281

• Tibial sag → the tibial tuberosity is not as prominent on palpation due to caudal displacement due to pull from semis • Abrupt stop on drawer from the CrCl

Question 282

• What is the preferred initial treatment of CdCL injury in dogs and cats?

Answer 282

• Conserviatve - 3-6 wks, if no improvement can be more aggressive

Question 283

• What are indications for surgical treatment of CdCL injury?

Answer 283

• Large breed w/high activity ie working dogs • Acute avulsion injury from the femoral origin • Failure of conservative management

Question 284

• What is more common, avulsion of femoral or tibial attachment of the cdcL?

Answer 284

• femoral

Question 285

• What are 3 fixation methods for avulsion of the caudal CCL?

Answer 285

• Fragment reduced + fixed with: • Bone screw • Wire suture formed from loop of cerclage wire • Divergent k-wires • [Image in source document]

Question 286

• What is approach if femoral avulsion? Tibial avulsion?

Answer 286

• Femoral - lateral approach to the stifle • Tibial - caudomedial

Question 287

* What are 6 techniques for stifle stabilization following mid-substance tear of the CdCL?

Answer 287

Medial: * caudomedial joint capsule imbricated w/mattress sutures * large suture placed from medial edge of patellar lig, just distal to apex of patella → drill hole in the caudomedial aspect of tibia Lateral: * Large suture from proximolateral edge of patellar ligament → just distal to apex of patella → drill hole in the fibular head * Caudolateral joint capsule → imbricated with mattress stures * +/- fascia lata strip pedicled at proximal patella and sutured to the fibular head as augmentation Desmodesis of MCL Tenodesis of LDE vs popliteal tendons Caudomedial joint capsule imbrication + fascia lata augmentation

Question 288

• What are the muscles of the quadriceps mechanism and where do they attach?

Answer 288

• Rectus femoris → ilium cranial to the acetabulum • Vastus lateralis, medialis, intermedius → GT

Question 289

• What are 8 common anatomic findings associated with MPL in small breed dogs?

Answer 289

• Coxa vara - decreased angle of inclination, decreased anteversion angle • Femoral varus • Genu varum • Shallow trochlear groove • hypoplastic/absent medial +/- lateral trochlear ridges • Hypoplasia of medial femoral condyle → worsens femoral varus • Medial displacement of tibial tuberosity • Internal rotation of tibia relative to femur • Proximal tibial varus • Internal rotation of the foot

Question 290

• What is thought to be the mechanism of distal femoral varus + internal rotation of the tibia?

Answer 290

• Initial coxa vara → diminished anteversio angle → displacement of quad mechanism medially → abnormal force on distal femoral physis = retards growht of medial femoral conydyle

Question 291

• What is id’d as a risk factor for developing MPL in SOME small breeds?

Answer 291

• Coxa valga

Question 292

• Is patellar luxation inherited?

Answer 292

• Yes it is a congenital disease because the luxation is not present at birth but the predisposing factors are

Question 293

• What is % medial vs lateral luxation in small breeds? Ratio of female to male?

Answer 293

• 95-98% medial • 2-5% lateral • Female:male 1.5:1

Question 294

* What is the Q angle, and how is it related to grades of MPL vs CCL?

Answer 294

* Q angle is the deviation of force of the quadriceps femoris muscle and can be calculated * Reference of of origin of rectus femoris + deepest part of groove + attachment of patellar ligament on theTT * 12.2 in g1, * 24.3 in G2, * 36.6 G3, * 19 with CCL rupture

Question 295

• What are the deformities present in Grade 2 luxation?

Answer 295

• Tibial valgus • Femora varus • Internal rotation at the stifle

Question 296

• What are the deformities present in Grade 3/4 luxation?

Answer 296

• Coxa vara • Femora varus • Tibia valgus • Internal rotation of the stifle

Question 297

• What is the risk of MPL following correction for CCL in large breed dogs?

Answer 297

• 0.018%

Question 298

• What is % of older dogs with chronic MPL that have concurrent CCL?

Answer 298

• 15-20%

Question 299

• What radiographic view may be helpful to determine the depth of the trochlear groove?

Answer 299

• Skyline • Can do CT

Question 300

• What are indications for surgical treatment of MPL in small breed dogs?

Answer 300

• G 3-4 → sx to mitigate progression • G2 → if CS significant • Ie, lameness > 2-3 weeks • >3 episodes of lameness in short time ie 1 mo

Question 301

• What is the surgical treatment for young dogs?

Answer 301

• Two stage treatment • ST and trochlear chondroplasty first • Reconstructive techniques when done growing - TTT, DFO, block or wedge trochleoplasty

Question 302

* What are 2 techniques to address MPL in skeletally immature dogs?

Answer 302

* Soft tissue reconstruction/imbrication * Trochlear chondroplasty

Question 303

• What is the goal for trochleoplasty?

Answer 303

• <50% of patella protruding beyond top

Question 304

• What are the 4 types of trochleoplasties?

Answer 304

• Block • Wedge • Abrasion - Sulcoplasty • Chondroplasty

Question 305

• Why is sulcoplasty not preferred over other methods?

Answer 305

• Does not retain the hyaline cartilage of the trochlea • Slower return to function • Crepitus and erosion of the cartilage of the patella within 4 weeks postop

Question 306

• What was performed to lead to improved fibrocartilage filling of trochlear defects following trochlear sulcoplasty (abrasion trochleoplasty) at 4 weeks, vs 40 weeks in untreated stifles?

Answer 306

• Resurfacing with autogenous periosteal graft → filled with fibrocartilage at 4 wks vs 40 wks in untreated

Question 307

• What is the age cut off for trochlear chondroplasty?

Answer 307

• <6 mo

Question 308

• What trochleoplasty guidelines must be followed for success in wedge recession?

Answer 308

• 3 osteotomies - two to form the wedge and a third that must be parallel to deepen the wedge in the femur • Must be wide enough for the patella • Deep enough to cover 50% • Long enough that it articulates with the patella for the entire length

Question 309

• What are the 2 devices that can be used to form wedge recession?

Answer 309

• Hobby saw • Sagittal saw

Question 310

• What has been shown to be true about block recession when compared to wedge recession?

Answer 310

• Deeper groove • Increased patellar articulation • Recession of a larger percentage of the trochlear surface • Greater resistance to reluxation

Question 311

• What is TTT correcting?

Answer 311

• Medial displacement of the tibial tuberosity

Question 312

• Where should the osteotomy start and how wide should it be for TTT?

Answer 312

• ½ the width of the tibial tuberosity to the cranial articular margin • Should start 3-4mm proximal to the insertion of the patellar tendon

Question 313

• What are the fixation techniques for TTT?

Answer 313

• K-wires - one or two • Pin and TB

Question 314

• In what scenarios is it appropriate for soft tissue recon to be the only procedure that MPL is treated with?

Answer 314

• Young patients that are skeletally immature, underoing stage 1 of a 2 stage treatment • Traumatic luxations

Question 315

• What 2 tissue layers are commonly released for soft tissue in MPL?

Answer 315

• Medial retinaculum • Joint capsule - capsulotomy

Question 316

• In grade ¾ w severe malalignment of the quads, what additional tissues can be released?

Answer 316

• Entire quads from femur • Laterally - vastus lateralis + biceps femoris • Medially - vastus medialis + caudal head of sartorius

Question 317

• What 2 tissue layers are commonly imbricated for soft tissue in MPL?

Answer 317

• Joint capsule • Fascia → biceps femoris fascia often

Question 318

• What Are 2 techniques to help correct internal rotation of the tibia, if the animal is skeletally immature?

Answer 318

• Fabellotibial suture • Fibular head transposition

Question 319

• What are the skeletal abnormalities in large breed dogs with MPL?

Answer 319

• Coxa vara - decreased angle of inclination • Retroversion of the femur

Question 320

• What does this initial deformity lead to that contributes to MPL?

Answer 320

• Internal rotation of the stifle • Genu varum • Femoral varus • Hypoplasia of the medial condyle • Proximal tibia varus or valgus • Tibial torsion • Medial displacement of the tibial tuberosity

Question 321

• What % of large breeds of dogs with MPL have concurrent CCL tears?

Answer 321

• 41%

Question 322

• What are the proposed causes of MPL in large breed dogs?

Answer 322

• Coxa varum • Distal femoral varus • Patella alta or long patellar tendon • CrCl repair → occurred in 0.018% of stabilization procedures

Question 323

• What is an L:P ratio that is consistent with patella alta? (L = length of patella ligament, P patlla length)

Answer 323

• >1.97

Question 324

• What are 2 factors associated with MPL in large breed dogs?

Answer 324

• Long patellar ligament, and patella alta

Question 325

• What is associated with MPL in labradors specifically?

Answer 325

• Distal femoral varus

Question 326

• How is femoral condyle orientation on mediolateral radiographs related to torsion or varus/valgus deformity?

Answer 326

• Double condyle sign → two condyles that are not superimposed • If one is DISTAL to the other → varus/valgus • If one is CRANIAL to the other → torsion

Question 327

• How is distal femoral varus measured on a normal radiograph?

Answer 327

• aLDFA

Question 328

• How is the anatomic axis of the femur determined?

Answer 328

• Draw point in center of femur at 33% and 50% the length, and draw line connecting two

Question 329

• How is the distal joint reference line id’d?

Answer 329

• Line connecting most distal aspect of medial and lateral condyles of the femur

Question 330

• How is the CORA of the femur w/varus determined?

Answer 330

• CORA is the intersection of the proximal and distal anatomical axes, and magnitude can be measured in this location • Use opposite normal femur as a reference for aLDFA vs breed measures (94-98)

Question 331

• How is femoral torsion determined?

Answer 331

• Axial radiograph or CT (down the shaft) • Anteversion angle • Angle between the transcondylar axis and the axis through the center of the femoral neck

Question 332

• What is the mean anteversion angle, and when should surgery be considered for correction of torsional abnormalities?

Answer 332

• 27 degrees • In angle <27 = consider correction • >27 degrees = surgery not necessary

Question 333

• What is the most accurate method of imaging/evaluating femoral torsion?

Answer 333

• CT > rads

Question 334

• What are the surgical treatments for femoral torsion?

Answer 334

• Closing wedge • Opening wedge • Detorsional osteotomy • Radial osteotomy • Plate fixation

Question 335

• What are the surgical treatment options to treat CCL rupture + internal torsion of tibia w/MPL in large breeds?

Answer 335

• TPLO w/internal tibial torsion correction

Question 336

* What are surgical treatment options for MPL + CCL rupture in large breeds without internal torsion ?

Answer 336

* TTT and lateral suture * Tibial closing wedge ostectomy + TTT * TPLO + TTT * TPLO + Cranial closing tibial wedge ostectomy + lateral translation of tibial tuberosity segment

Question 337

• What was the reduction in reluxation rates when recession trochleoplasty was performed in addition to TTT?

Answer 337

• 5 fold decrease in reluxation

Question 338

• What is an essential component to G4 MPL correction?

Answer 338

• ALD correction

Question 339

• How is DFO alignment achieved?

Answer 339

• Jig applied to cranial tibia • If no torsion jig pins placed parallel to sagittal plane • If torsion jip pin is placed parallel to proximal femur sagittal plane • After cut can reduce by putting bone forceps around pins • If torsion bend jig pin to correct torsion → angle in pin should be equivalent to the amount of torsion to be corrected

Question 340

• What is the reluxation rate in MPL?

Answer 340

• 8 - 48% • No reluxation in DFO

Question 341

• What is the major complication rate in G4 MPL repair?

Answer 341

• 24-27%

Question 342

• What skeletal abnormalities are associated with LPL?

Answer 342

• Coxa valga • Increased angle of anteversion • Genu valgum

Question 343

• What is the incidence of LPL amongst small, medium, large, and giant breed dogs?

Answer 343

• 2% - small • 19% - medi • 17% -large • 33% - giant

Question 344

• What breed may have higher risk for LPL?

Answer 344

• Cocker spaniels

Question 345

• What are the skeletal consequences of LPL during development?

Answer 345

• Hypoplasia of the lateral femoral condyle • Hypoplasia of the lateral ridge of the trochlea

Question 346

• RAdiographically, what is LPL associated with?

Answer 346

• Long proximal tibia • Patella baja

Question 347

• What is the presumed mechanisms of anatomic change leading to LPL in dogs?

Answer 347

• Altered laoding of femoral condyles durin development → increasd force through lateral portion of distal femoral physis = retarded growth = lateral ocndylar hypoplasia + distal femoral valgus → genu valgum (knock kneed)

Question 348

• What are typical deformities seen with LPL (2) and what is a deformity that can be seen in isolation and requires surgical treatment?

Answer 348

• Distal femoral valgus + increased femoral torsion angle • OR internal femoral torsion ie increased angle of anteversion is only deformity id’d, in which case surgery should be pursued

Question 349

* What angle should be measured and what should it be corrected to if the other limb is not normal?

Answer 349

* aLDFA * 94-98

Question 350

• When should torsion be corrected?

Answer 350

• Torsion angle > 27

Question 351

• What are 2 factors associated with risk of reluxation?

Answer 351

• Dogs > 20 kg • Not performing trochleoplasty in addition to TTT • Luxation and Collateral Ligaments

Question 352

* Which collateral ligament in the stifle is more often injured?

Answer 352

MCL>LCL

Question 353

• What are the 3 degrees of ligament injury, and which ones warrant surgery?

Answer 353

• 1- minor overstretching w/intact fibers • 2 - tearing of some fibers • 3- complete tearing or avulsion of the ligament, ligament non-functional • *grade 3, some 2s warrant sx

Question 354

• What are the functions of the collateral ligaments in extension? Flexion?

Answer 354

• Extension = both taught • Eliminate varus (LCL) and valugus (MCL) and rotation • Flexion • MCL is taut, LCL is lax • Some internal rotation • No external rotation due to LCL

Question 355

• If a joint is identified to be unstable, what other structures are likely to be injured in addition to collaterals?

Answer 355

• Meniscus, cruciates

Question 356

• Which collaterals are taut in extension? Flexion?

Answer 356

• MCL/LCL taut in extension • MCL taut in flexion only

Question 357

• What test can be used to interrogate the LCL/MCL, and what does mild vs marked abnormality mean?

Answer 357

• Varus stress test (LCL) → open the lateral joint • valgus stress test (MCL) → open the medial joint • Mild - isolated injury to collateral; marked = likely cruciates are involved

Question 358

• What can be managed conservatively?

Answer 358

• Single collateral ligament damage can be managed with stabilization for 8 weeks

Question 359

• What vessel/nerve can become damaged/entrapped in cases of stifle joint luxation?

Answer 359

• Popliteal a. • Peroneal n.

Question 360

• How is each ligament investigated in a traumatic luxation of the stifle?

Answer 360

• Cranial drawer → CrCl • Caudal drawer → CdCl • Varus → LCL • Valgus → MCL • Internal rotation → CrCl and some MCL in extension • External rotation → LCL

Question 361

• What step is performed prior to any attempted joint/ligament reconstruction in a luxated stifle

Answer 361

• Temporary stabilization of the joint in standing angle → 140*, • transarticular k-wire or steinmann pin from tibial crest through the intercondylar area of the femur • Decreases risk of stabilizing the joint or repairing the joint in a luxated position

Question 362

* What is the technique for repair of midsubstance repair of torn ligaments?

Answer 362

* Primary repair with locking loop pattern anchored to bone anchors

Question 363

• What is the technique for repair of avulsed attachments (2)

Answer 363

• Avulsed bone fragments repaired/attached with k-wires • Bone screws + spiked washer

Question 364

* What are methods of augmenting/protecting primary ligament repair?

Answer 364

Transarticular suture connected to: * Bone screw + washers * Bone anchors * Bone tunnels Transarticular ESF * Static, Hinged * 6-8 weeks Transarticular pin * Max 5-7 wks * Distal of tibial crest → intercondylar area → femur

Question 365

• When tightening the reattachment/suture of collaterals, what position should the stifle be in?

Answer 365

• Extension - prevents over tightening of the suture

Question 366

• What are 2 most common major compilations for stifle joint luxation repair?

Answer 366

• Arthrofibrosis • Recurrent joint instability

Question 367

• What is the average loss of joint flexion following this injury?

Answer 367

• 30-40 degrees • Patella Fracture 1162

Question 368

• What is the etiology of patella fx in dogs (2) vs cats?

Answer 368

• Dog - direct trauma / complications from TPLO • Cat - stress fx (from jumping)

Question 369

• What are 2 PE findings specific for patella ligament rupture?

Answer 369

• Patella alta • Involuntary stifle flexion during stance - cannot extend stifle

Question 370

• What are 2 methods of patella fracture stabilization?

Answer 370

• Pin and tension band → 70-86% failure • Locking plate

Question 371

• What are the classifications of patellar fractures?

Answer 371

• Displaced or nondisplaced • Comminuted, or transverse body fractures • Apical, basilar or body

Question 372

• What patellar fractures can be treated conservatively?

Answer 372

• Nondisplaced or minimally displaced apical or basal fx

Question 373

• How is a nondisplaced -minimally displaced patella body fx treated? (2)

Answer 373

• K-wire from base to apex in a predrilled hole + tension band • OR circumferential cerclage + tension band through tendon of quad prox to patella → distal

Question 374

• How is a displaced transverse body fx treated? (1)

Answer 374

• K-wire from base ot apex + single or double tension band with wire fixation • 20 g wire in small dog • 16-18 g in med-large

Question 375

• How is a comminuted patellar fx treated (3)

Answer 375

• K-wire reconstruction • Circumferential cerclage • Tension band

Question 376

• What are 3 methods of protecting patellar fracture (or ligament) repairs?

Answer 376

• Transarticular ESF → hinged at 4-6 wks • Mattress sutures → through patella or tendon proximal to patella → drill hole in tibial tuberosity • Suture vs wire • Patellar ligament plating • Attached to the tibial tuber w/screws + tendon to quad w/sutures

Question 377

• What is an alternative fixation method for patellar repair other than pin and TB?

Answer 377

• Plating • Plate from tibial tuberosity extending proximally to the insertion of the quadriceps into the patellar tendon • Screws in tibial tuberosity and into the soft tissue of the tendon

Question 378

• Prognosis for patellar fracture and patellar ligament rupture?

Answer 378

• Fracture → poor to good depending on degree of fracture • Rupture → fair to good • All have decreased ROM • Patellar Ligament Rupture 1164

Question 379

• How is patella ligament rupture repaired?

Answer 379

• Suture or orthopedic wire placed from proximal to patella into holes in tibial tuberosity and patella directly apposed with locking loop • Plating • [Image in source document]

Question 380

• What can be used to augment patellar ligament repair?

Answer 380

• Augmented with autogenous fascia lata grafts sutured into defect or spanning from the patella to the tibial tuberosity

Question 381

• What is the most common location for femoral OCD?

Answer 381

• Axial aspect of lateral condyle (96%) (medial on lateral femoral condyle) • Axial aspect of medial condyle (4%) (lateral on medial femoral condyle)

Question 382

• What is the most common → least common OCD locations in the dog?

Answer 382

• Shoulder > elbow > tarsocrural > stifle

Question 383

• What is common signalment for stifle OCD?

Answer 383

• Male, large-giant breed, 5-9 mo

Question 384

• What breeds are predisposed to stifle OCD?

Answer 384

• Great dane • Labrador • Golden • Newfie

Question 385

• What are the common radiographic findings?

Answer 385

• Subchondral bone defect with sclerosis of the adjacent bone • Effacement of the infrapatellar fat pad • Mineralized free bodies • Osteophytosis

Question 386

• What can be mistaken for OCD on radiographs that is present on the lateral femoral condyle?

Answer 386

• Extensor fossa → located cranially

Question 387

• What are 2 treatments for stifle OCD?

Answer 387

• Removal of cartilage lesion via scope vs arthrotomy +/- forage +/- micropicking

Question 388

• OATS

Answer 388

• Graft from distal lateral/medial trochlea at sulcus terminalis of trochlear ridges

Question 389

• What is the prognosis for stifle OCD?

Answer 389

• Fair to poor • Continued OA, persistent lameness • Avulsion of the LDE 1165

Question 390

• What is the origin and insertion of the LDE, and function?

Answer 390

• Origin at the extensor fossa at the lateral femoral condyle, inserts on digits 2-5 • Flex tarsocrural joint + extend digits

Question 391

• What PE finding is consistent with avulsion or luxation of LDE?

Answer 391

• Fully flex stifle, fully extend tarsus, and fully flex digits without tension

Question 392

* What can cause luxation of the LDE?

Answer 392

TPLO, patellar luxation

Question 393

• What PE findings are consistent with luxation of the LDE?

Answer 393

• None • Intermittent NWB lameness • Can feel luxation during ROM • Can cause luxation when flexing the stifle and pushing up on the foot • Can hear an audible click during stance phase

Question 394

• What are options for acute avulsion of LDE? Chronic?

Answer 394

• Acute - reattach with lag screw + plastic washer • Chronic - excise hypertrophic bone + reattach to proximal tibia • Sutured to joint capsule or fascia of cranial tibial muscle w/absorbable or nonabsorbable suture

Question 395

• What is the treatment for luxated LDE?

Answer 395

• Bone tunnels at cr/cd margin extensor groove (prominences) + mattress suture between bone tunnels to trap tendon underneath • Can deepen the groove with rasp or rongeur • Gastrocnemius Avulsion 1166

Question 396

• What is the origin and insertion of the gastrocnemius and its function?

Answer 396

• Lateral and medial bellies of the muscle originate on the lateral and medial supracondylar tuberosities • Each muscle contains a sesmoid bone within its origin

Question 397

* What comprises the common calcaneal tendon?

Answer 397

* Gastrocnemius tendon * Conjoined tendon of the semitendinosus, gracilis and biceps femoris * SDFT

Question 398

• Which fabella is larger, lateral or medial?

Answer 398

• lateral

Question 399

• What are radiographic findings associated with avulsion of the gastroc muscle?

Answer 399

• Distal displacement of 1-2 fabella, and associated soft tissue swelling

Question 400

• What is the basic technique of gastrocnemius avulsion repair?

Answer 400

• Circumfabellar suture + anchored in soft tissue caudal to the femur • Anchored to femur via bone tunnel vs bone anchor • [Image in source document] • Arthrodesis 1166

Question 401

• What is the angle of stifle fusion for cat and dog stifles?

Answer 401

• Cat - 120-125 • Dog - 135-140

Question 402

• Where is the bone plate placed?

Answer 402

• Cranial spanning 60-70% of each bone (femur and tibia)

Question 403

• How is the best way to achieve an angle of 140 intra-operatively?

Answer 403

• 2 k-wires perpendicular to the sagittal axis of each bone • 2 more k-wires at 20 deg to the original wires → these wires are the direction of the osteotomy • Desired angle is 140 deg • 180 deg - 140 deg = 40 deg • Divide 40 deg by each bone to get 20 deg

Question 404

• How is the tibial tuberosity reattached and what should be considered when reattaching it?

Question 405

• What % of the femur/tibia should the plate span for arthrodesis of stifle?

Answer 405

• 60-70%

Question 406

* What adaptation to the distal and proximal extent of the bone plates reduces risk of fracture at the stress riser of bone plate → bone?

Answer 406

* Periosteal new bone = adaptation to increased stress

Question 407

• What is a complication that can be seen after arthrodesis?

Answer 407

• OA in hip and tarsus due to abnormal weight bearing