1
Q
- Where does the cranial/caudal insert on the femur/tibia?
A
CrCL→
- fossa caudomedial aspect of lateral femoral condyle → cranial intercondyloid area of plateau subadjacent to intermeniscal ligament + cranial horn medial meniscus
- Thinner craniomedial band & larger caudolat band
- Craniomedial band = more caudal/prox origin on lateral femur & inserts on craniomed aspect of cranial articular surface of plateau(fascicles deformed around larger once of caudomed band during flexion)
- Caudolat band is shorter/straighter & inserts along caudolateral aspect of tibial attachment of intercondyloid area
Cranial intercondyloid area
CdCL→
- Attaches to lat surface of medial fem cond & runs caudodistally to attach to medial edge of popliteal
notch of tibia, medial to caudal meniscotibial lig of lat meniscus.
2
Q
• What is the importance of the parapatellar firbocatilages?
A
• Prevent patellar luxation
3
Q
• What is the attachment site for the CrCL and cranial meniscus ligaments?
A
• Cranial intercondylar area = oval depression, cr to intercondylar eminence
4
Q
• Where is the attachment site for the caudal meniscus ligament?
A
• Caudal intercondylar area = small depression cd. To the intercondylar eminence & cranial to popliteal notch
5
Q
• Where is the attachment site of the caudal cruciate ligament?
A
• medial edge of the broad popliteal notch (separates the tibial condyles)
6
Q
• What 3 structures attach to the tibial tuberosity?
A
• Patellar ligament
• Biceps femoris
• Sartorius muscles
7
Q
• Which meniscotibial ligament attaches more cranial, the medial or lateral? How are they in reference to the cranial cruciate ligament attachment site?
A
• Medial is most cranial, cranial to the cranial cruciate ligament
• Then lateral
8
Q
• What are differences in attachments of the caudal lateral meniscotibial and medial meniscotibial ligaments?
A
• Medial - attaches to caudal intercondyloid area of the tibial
• Lateral - attaches to the popliteal notch
9
Q
• What is the attachment site of the meniscofemoral ligament of the lateral meniscus?
A
• Intercondylar fossa of the femur
10
Q
- What are the ligaments and attachments sites of the medial meniscus?
A
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 → caudal part of the cranial meniscotibial ligament
11
Q
• What are the ligaments and attachment sites of the lateral meniscus?
A
• 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
12
Q
• What are origin and attachment of the cranial cruciate ligament?
A
• Origin - caudomedial of lateral femoral condyle AND caudolateral par of intercondylar fossa of femur → cr/med/distal direciotin → cranial intercondyloid area of tibia
13
Q
• What is the main difference between cranial and caudal cruciate ligaments?
A
• Attachment sites
• Caudal Cruciate = larger than cranial
14
Q
• Why is the lateral meniscus not associated with the lateral meniscus and joint capsule?
A
• It passes over the tendon of origin of the popliteal m. and inserts on the fibular head
15
Q
• What Ligament attaches the meniscus to the joint capsule at the medial meniscus?
A
• Coronary ligament
16
Q
• What structure is interposed between the lateral meniscus and lateral collateral and the joint capsule, preventing tight adherence of the two structures?
A
• Popliteal muscle
17
Q
- Why is the lateral meniscus less likely to be injured during movement?
A
Lateral meniscus
- Meniscofemoral attachement to femur + relationship to popliteal tendon = couple motion bw femoral condyle + lat meniscus during rotation = less likely to be injured vs relatively immobile medial meniscus
18
Q
- What are the 3 layers of the meniscus composed of and what forces do they resist?
A
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
19
Q
- What are the 3 regions of blood supply to the meniscus?
A
- 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
Med & lag genicular art**
20
Q
• Describe laxity of MCL and LCL in flexion, then extension?
A
• MCL/LCL TAUT in extension = minimal rotation of tibia as primary stablizers
• CdMCL(very small portion) + LCL = LAX in flexion → allows lateral femoral condyle to displace caudally → internal rotation of the tibia
Majority of MCL taut in flx
21
Q
• What limits varus and valgus at 90 deg flexion?
A
• 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
22
Q
- 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?
A
Craniomedial
- taut in flexion AND extension
- primary against cranial tibial translation
Caudolateral
- taut in extension, relaxed in flexion
- secondary against cranial tibial translation
23
Q
• What is primary purpose of caudal cruciate ligament ?
A
• Restraint against cd tibial translation with respect to the femur
• limits internal rotation
• Limites hyperextension
• Limit varus and valgus
24
Q
• What is one of the main functions of the meniscus that when removed contributes to postop articular cartilage degeneration?
A
• Load bearing and force distribution, shock absorption, joint stability
• Protect the articular cartilage by lowering the stress on the articular cartilage
25
• How much load to the menisci bear
• 40-70% across the joint
26
• Describe the relationship of the meniscus to load.
• 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
27
• What is the role of the meniscus with relation to stability in the intact cruciate joint vs. non-intact?
• Intact joint → secondary role for joint stability
• Cr defficient → caudal wedge of the meniscus prevents sublux
28
• What occurs after caudal and full menisectomy?
• 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
29
• What happens at the stifle during gait in Cr deficient dog and how is this compensated for?
• Remains flexed
• Increased extension of the tarsus and the hip to compensate
30
• What aids to reduce the cranial translation of the tibia during swing phase in CrCl?
• Meniscus acts like a spring at the end of stance phase
• Important secondary stabilizer
31
• What is the active model of the stifle (Slocum)?
• 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
32
• What does the magnitude of cranial tibial thrust force depend on?
• Joint compression forces
• Tibial plateau angle
33
• How does the TPLO address this active model?
• Decreases the cranial tibial thrust force so that there synergism between the muscle forces and passive restraints by decreasing the tibial plateau
34
• In the active model of the stifle, what counteracts normal cranial tibial thrust force?
• Caudal thigh muscles (active)
• Cranial cruciate ligament and caudal pole of meniscus (passive)
35
* What is the Tepic model of the stifle?
* 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
36
* Based on Tepic’s model, what strategies should be employed to stabilize the stifle?
* Leveling plateau so that it is perpendicular to the patella ligament
* Altering angle of patellar ligament so it is perpendicular to the plateau
* Avulsion of the CrCl
37
• What structure makes avulsion of the CCL in immature animals more common vs mid-substance tear?
• Sharpey’s fibers → attachment to the bone is stronger than the bone in young animals
38
• Avulsion of attachment to femur or tibia is more common?
• Tibia >> femur
39
* Treatment for avulsion
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
40
• What is reported degree change following epiphysiodesis of cranial tibial plateau in dogs, and what is a common complication?
• 4-24 degree reduction in the plateau
• Valgus deformity (3/22 joints)
41
• What 3 forces can increase risk of acute traumatic rupture of the CCL?
• Excessive loading
• Stifle hyperextension
• Excessive internal rotation of the tibia
42
• What are 5 factors associated with CCL disease in dogs?
• 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
43
• What is the protective mechanism of the cruciate that is enacted by the musculature of the pelvic limb?
• 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
44
• What is the risk for dogs rupturing contralateral CcL, and median time from first diagnosis? What factors are associated with contralateral tear?
• 22-54%
• 947 d from time of original CCL
• Factors - increasing age = protective ,
• NOT associated with increased risk in labs -
• Weight, age TPA, sex,
45
• What structures minimize cranial drawer when the stifle is in full extension?
• Collateral ligaments taut in full extension = minimize cranial drawer
46
* What is tolerated degree of translation for “puppy drawer”
* 3-5 mm
* Will have an abrupt stop = CrCl
* also for severely muscle wasted pelvic limbs in adults
47
• Drawer in flexion, which band is torn and why?
• Craniomedial band - caudolateral taut in extension only, so would elicit drawer in flexion only
48
• What is the PE finding if the caudolateral band is torn and the craniomedial is intact?
• No drawer sign because the craniomedial is taut in flexion and extension
49
• Why does drawer test elicit translation of the cruciate ligament? Why does the tibial compression test?
• Drawer- craniocaudal translation by direct pressure
• Compression - creates stifle joint compression by simulation the contraction of the gastro muscle = tibial compression= cranial translation
50
* What is the risk of latent/postliminary meniscal tears in dogs?
* 2.8-26.8%
* Latent = present at the index procedure but are not ID because of failure of
diagnosis @ surgery.
* Postliminary = tears that occur after initial sx; they may result from residual stifle joint instability
51
* What are risk factors for post operative (latent vs postliminary) meniscus tears in dogs?
Increased risk for dogs with intact meniscus @ first sx (vs meniscus release vs meniscectomy)
TTA
- 6x more likely than tight rope,
- 3x more likely than TPLO
Inappropriate stabilization
Complete CCL tear 10x more likely to have medial meniscal disease than partial
52
* What type of tear is most common in the medial meniscus vs lateral meniscus?
Medial
- Vertical longitudinal tears (bucket-handle) caudal pole
- Shear stress to longitudinal and radial fibers from entrapment during cranial tibial translation
Lateral
* 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
* Lateral meniscal tears should be treated conservatively= could have significant compromise of joint function
53
• What % of Postliminary tears presented with a meniscus click
• 27%
54
• What is incidence of meniscal mineralization in cats, and what are associated risk factors?
• 46%
• Older age, lower weight, lower BCS
55
• What are the 3 approaches to the stifle that can be performed to view the caudal pole of the medial meniscus?
• Craniolateral
• Craniomedial
• Caudomedial
56
* What are 2 minimally invasive instruments used for partial meniscectomy?
* 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
57
* What are the 3 types of menisectomies and what are their indications?
Caudal Hemi-menisectomy
* 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
58
* What is the extent of the caudal or segmental hemi-meniscectomy?
* Mid-body to transect caudal meniscotibial ligament
* For complex and degenerative tears, peripheral detachmetns w/macerated portions or peripheral detachments that cannot be repaired
59
* What is the extent of a total meniscectomy?
* Transection of cd/cr meniscotibial ligaments
* Rare
60
• What is extent of a partial meniscectomy?
• Removal of a damaged axial section of meniscus while preserving cranial/caudal meniscotibial ligaments
61
• What is the goal of the meniscus release?
• To move the meniscus caudolaterally and take it out of the way of the impingement between the medial femoral and tibial condyle
62
• What are the 2 types of meniscus releases?
• Caudal
• Central (mid-body)
63
* What are the two techniques for mid-body release?
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
64
• What is the likelihood of postliminary tears after TPLO on scope vs arthrotomy?
• Dogs 4x more likely to get postliminary tear after arthrotomy w/out release vs scope w/out release
65
* When can a meniscus be repaired?
* When the tear is in the red-red zone
66
* What is the difference in long term postop with or without meniscus?
* Dogs with meniscal release or menisectomy had decreased function and more OA at 3-5 yrs post-op
67
• What are the the four extra-articular methods of stabilizing the stifle joint?
• Lateral fabellar suture
• Tight Rope (Arthrex)
• Swivel Lock (Arthrex)
• Fibular head transposition
68
* Describe the process of lateral suture (DeAngelis)
* 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
69
* What is the least isometric points of the femur/tibia for suture anchors?
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
70
• In a radiographic analysis, what was the most ideal femoral point paired with which tibial point?
• 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 (F2-T3)
71
• What is the infection and complication rate of lateral fabellar suture?
• Infection 4.6%
• Complication 17.4%
• Peroneal nerve deficits
• Suture pulled through gastroc
• Incision complications
72
• How does lateral suture compare to TPLO?
• 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
73
* What is the tight rope technique and what suture and points are used?
* 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
74
* What is the swivel lock (arthrex) technique?
* 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
75
• How did symmetry indices for PVF and VI compare between lateral suture and TPLO at 6 amd 12 mo post op?
• 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
76
• What is the difference in outcome between dogs with low TPA and high TPA?
• None, TPA did not have affect on outcome for suture method
77
• What is the postliminary tear reported in dogs with meniscal release + lateral suture, vs no meniscus release?
• 0% for release
• 15.2% in dogs without release
78
• What factors are associated with increased risk of complications with lateral suture?
• High body weight and young age at time of surgery
79
• What is the alternative to suture techniques for extracapsular repair and how is it performed?
• 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
80
• What is the biomechanical function of fibular head transposition in relation to a CCL deficient joint?
• Prevent cranial drawer movement and min. Internal rotation of the tibia
81
• What are common complications associated with fibular head transposition?
• LCL tear
• Fibular head fracture
• Ost op instability
• seroma
82
• What are the types of intra-articular techniques used for reconstruction of the CrCl?
• Allografts
• Xenografts
• Autografts
• Synthetic
83
• What is the over-the -top procedure for autografts in the dog?
• 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
84
• What is the proposed “weak link” of the patellar ligament graft in the “over the top” method in dogs?
• 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
85
• What is a common downside to synthetic prosthetic CCL? What was a major complication of Gore Tex synthetic graft?
• Creep
• Mechanical fatigue led to swear debris = synovial reaction from particulates
86
• What is augmentation?
• Used to protect the graft during its initial reincorporation
• Kennedy ligament
• Polypropalene ribbon
• Did not have the strength as the implanted graft
• Failed
87
• Describe the over-the-top procedure.
• Harves patellar tendon still attached to the tibial tuberosity
• Pull through the joint
• Attach to the lateral shaft of the femur
88
• Describe the attachment of synthetic graft.
• 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
89
• When passing an “over the top” graft in a canine stifle, what intra-articular structure must be appropriately prepared to prevent impingement?
• Intercondylar notch - remove osteophytes
90
* How is the graft passed through the joint?
* 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)
91
• What are 2 methods of securing a patellar graft to the femoral condyle?
• 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
92
* What are 2 methods of securing the patellar ligament graft to the tibia?
* 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
93
• What is considered the best method of fixing grafts to bone, and why?
• Interference screw to bone block → doesnt damage soft tissue of graft
94
• What are the reported complications with grafts?
• Persistent laxity
• Fracture of the tibial tuberosity with percurement of the graft
• Fx of the patella
95
* What are the 6 osteotomies for stifle joint stabilization?
- CTCWO - Cranial Tibial Closing Wedge Osteotomy
- TPLO
- TPLO, CCWO
- TTA
- TTO
- Modified Maquet
96
• What is the basis for CTCWO?
• Slocum model that cranial translation is caused by the tibial slope
• Magnitude of translation is comparable to magnitude of the TPA
97
• In a study evaluating CTCWO, at what TPA did they find stifle stability, and at what angle did they see caudal tibial subluxation occur?
• TPA+ 6 = stable
• TPA +7.5 or greater = caudal subluxation
98
• What is the desired final TPA angle for CTWO?
• 4-6 deg
99
• What are 3 methods of pre-operative planning for wedge in order to optimize lowering of the tibial plateau angle
• Measure TPA, and wedge should be the TPA -5
• Align cranial cortices + move proximal → more likely to end up with TPA of 6
100
• What is the outcome of tibial shortening on patella position and joint kinematics for CTCWO?
• Patella baja → stifle hyperextension
• stifle/tarsus hyperextension during swing phase, normal in stance phase
101
• What was the most common catastrophic complication of CTCWO that required re-operation?
• Catastrophic tibial fx, requiring multiple plates
102
* What other two procedures can CTCWO be combined with?
- TPLO, lat suture
103
• What osteotomy is the only osteotomy that can be performed on dogs with open growth plates?
• CTCWO → in dogs with open plates, that are too old for epiphysiodesis
104
• What other orthopedic abnormality can CTCWO treat?
• Patella alta → wedge brings the attachment to the patellar tendon lower on the tibia
105
• What are disadvantages of the CTCWO?
• Variability of post op TPA
• Shortening of tibia
• Patella baja
• +/-Craniocaudal angulation of tibia from longitudinal tibial axis shift
106
• What are the advantages of CTCWO
• Can be performed in young dogs with open growth plates
• Can correct very steep slopes
• Correct patella alta
• No special equipment
107
• 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)
• Varus or valgus deformity
108
* What are 3 plates commonly used for CTCWO?
- LCP, DCP, T plate
109
* What can be used to help with alignment intraop in CTCWO?
* TPLO Jig
110
• What happens when leveling to a TPA less than 6.5 deg in TPLO?
• 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
111
• What happens to the femoral contact area on the tibial plateau in stance following TPLO?
• More caudal than normal
112
• What forces does a TPLO neutralize, and which forces are not addressed by this surgery?
• Cranial subluxation
• Not addressed- Internal rotation or hyperextension
113
• What measurements are made on MedLat rads to determine the TPA?
• Mechanical axis
• Joint orientation lines
• TPA = mCdPTA
114
• What is assessed on mediolateral rads for TPLO planning
• Measure plateau angle
• Determine saw blade size
115
• Identify appropriate osteotomy location
• Quantify magnitude of required TPLO
• Confirm rotation is safe
116
• What is assessed on caudocranial rads for TPLO planning?
• 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
117
• What are the mean mMPTA and mMDTA values, and if frontal plane alignment varies from these what should be he outcome
• mMPTA 93, mMDTA 95
• Correct during TPLO
118
• What defines the tibial plateau axis?
• Line connecting cranial and caudal extent of the medial tibial condyle
• Synonymous with the proximal tibial joint orientation line in the sagittal plane
119
• What defines the mechanical axis of the tibial in the sagittal plane, ie the long axis of the tibia?
• Line drawn between the point dividing the intercondylar tubercles of the tibia, and the center of rotation of the talus
120
• How is the tibial plateau angle measured?
• 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
121
• What is intra and interobserver variability for TPA measurements, and what was associated with significant differences in TPA between observers?
• Interobserver - 3.4 degrees
• Intraobserver - 4.8-6 degrees
• Experienced vs inexperienced = sig different
122
• Where should the center of rotation of the osteotomy for accurate plateau leveling, and what occurs to the intercondylar tubercles as a result?
• 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
123
• What is D1? What is D2?
• 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
124
• What 3 structures constrain rotation of the proximal tibial plateau segment?
• Tibiofibular articulation
• Proximal jig pin
• Center of osteotomy
125
• What aides in rotation?
• 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
126
• What does using jig w/saw guide improve in the TPLO (2)?
• More accurate placement of osteotomy
• More accurate leveling of TPLO
127
• What was jigless TPLO associated with (3)?
• 15 degrees craniolateral deviation of osteotomy
• Increased risk of fibular fx
• Increased risk of fixation failure
128
• What does measuring rotation distance diagonally across the osteotomy lead to?
• Underrotation
129
• What does alignment of the cortices lead to when rotated? What is to be expected at the osteotomy?
• Realignment of the cortices causes angular and rotational deformity
• There should be a medial to lateral step after rotation
130
• How is modest to moderate varus corrected with TPLO?
• Distal jig ARM slides medially, ie away from the tibia → push the distal tibia away
131
• How is modest to moderate valgus corrected with TPLO?
• Distal jig ARM slides laterally, ie towards the tibia → pulls the distal tibia in medially
132
• How is modest to moderate torsion corrected with TPLO?
• 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
133
• What was the post-op range in TPA tolerated by dogs, if paired with meniscus surgery?
• 0-14 degrees
134
• What is the reported complication rate with TPLO?
• 18-28%
135
• What was the major, minor, and intraop complications in TPLO w/pre-contoured LCP plates + experienced surgeons?
• Intra op - 7%
• Minor - 5.4%
• Major - 0
136
• What is the cause of major hemorrhage in the TPLO?
• Cranial tibial artery
137
• Bilateral single stage TPLO is associated with what complication?
• Increased risk of complications 20-40%
• 8.5-9.6x increased risk of tibial tuberosity fracture
138
• What is the average change in TPA over the course of healing?
• Rock back caused by movement along the osteotomy site
• 1.5 +/- 2.2
• Locking plate = less change
139
• What 2 factors are associated with higher risk of patellar ligament thickening?
• Lower post op TPA (<6)
• Greater body weight
• Causes stress on the patellar ligament
140
• What are 3 (other)factors that are associated with patellar ligament thickening?
• 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
141
• What are factors that have historically been associated with development of post-op TPLO neoplasia?
• 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
142
• What are 3 indications for combined TPLO/CCWO
• Manage excessive TPA ie > 34 degrees when a radius of 24mm is used for the blade
143
• When rotation past insertion of the patellar lig. Is required
• Varus or valgus deformity
144
• How is CCWO planned?
• 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
145
• 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?
• Distal, prevent angle from entering TPLO
146
• What are 3 techniques to aid in performing a biplanar osteotomy when doing a combined TPLO/CCWO?
• 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
147
• How is Valgus correction performed with TPLO/CCWO?
• Coplanar medial closing wedge osteotomy
148
• How is torsional correction performed with TPLO/CCWO?
• Rotation at the level of a single osteotomy if there is no varus or valgus
149
• How is patella alta corrected with TPLO/CCWO?
• The amount the patella is moved is equivalent to the cranial cortex that is being removed
150
• How is the TPLO/CCWO performed? Which osteotomy is performed first? What is the method of fixation?
• 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
151
• What is the location with the slowest healing in the TPLO CCWO?
• The CCWO is the slowest healing
152
* What is the biomechanical theory behind the TTA?
* Joint force is parallel to the patellar tendon ; cranial and caudal tibiofemoral shear is based on the knee in flexion angle
* Goal = patella perpendicular to common tangent of femoral/tibial contact by advancing
* Tibiofemoral shear force becomes neutral or caudally directed during ambulation by creating this angle
153
• What is the goal of TTA?
• 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
154
• What is the standard position of a mediolateral radiograph for TTA planning?
• Almost fully extended, stifle at 135, centered on the joint, no cr translation
155
• What are 2 methods of preop measuring for TTA?
• Common tangent method (PTA^CT)= less variation reported
• Vs the PTA - TPA
156
* What is PTA^CT and how is it measured?
* 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
157
• What is the positioning and radiograph needed to measure for TTA?
• Orthogonal views with stifle extended to 135 standing angle
• Sitfle cannot be in drawer
158
• What is the biomechanical justification for TTA?
• 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
159
• Where should the cage be placed in TTA?
• 2-3 mm from the proximal tibial bone margin
160
• What are the modified types of TTA and what is their modification?
• Modified Maquet, TTA-rapid, TTA-2
• Cage only and osteotomy length depends on the size of the cage
161
• What is the overall complication rate of TTA?
• 19-50%
162
• What were the most common complications reported with TTA?
• Fracture of the TT
• Postliminary meniscal tears
• Patellar luxation
• Fx of the tibia
163
• What are the most common surgical technique errors?
• 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
164
• How is the cage positioned?
• Wider part is proximal
165
• What complication of TTA leads to increased risk of patellar luxation, and what are the 2 reasons for this intra-operatively?
• Malposition of the tibial tuberosity in the frontal plane
• Angled osteotomy
• Improperly contoured plate = translation
166
• What should be considered during plate selection?
• The location of the patellar tendon attachment site
• Low = shorter/lower plate
• High = longer plate
167
• What is the risk of a low patellar ligament attachment site with TTA?
• 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
168
• What is the recommended max TPA and max advancement distance?
• Max TPA 30 → 25 is recommended also
• 15 mm → largest cage there is
• Steeper TPA requires more advancement
169
• What is a technique for allowing additional advancement of the tuberosity?
• Transposing the cage distally causes more advancement
• can put tuberosity proximal to the cage at risk of fracture
170
• What is the downside for performing TTA with high (>30) TPA)?
• 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
171
• Can TTA be used to correct torsion, varus or valgus?
• NO - need medial or lateral wedges for that
172
• What procedure can be combined with TTA to address patellar luxation, and how should the cage be modified?
• 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)
173
• What is the goal of the TTO?
• Reduce TPA → wedge ostectomy
• Reduce patellar tendon angle to 90 degrees → partial frontal plane osteotomy of the tibial tuberosity
174
• What is the angle of the wedge osteotomy performed in a TTO?
• 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
175
• What are 2 methods that can be used to avoid overdoing the wedge ostectomy leading to TPA < 0 degrees in a TTO?
• 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)
176
• What is the primary function of the CdCL, and what does it aid the CCL in as well in terms of limiting forces?
• Primary stabilizer vs cd tibial translation,
• and functions with CCL to limit internal rotation and hyperextension
177
• What is a PE finding to diagnose CdCl rupture?
• 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
178
• What is the preferred initial treatment of CdCL injury in dogs and cats?
• Conserviatve - 3-6 wks, if no improvement can be more aggressive
179
• What is more common, avulsion of femoral or tibial attachment of the cdcL?
• femoral
180
• What are 3 fixation methods for avulsion of the caudal CCL?
• Fragment reduced + fixed with:
• Bone screw
• Wire suture formed from loop of cerclage wire
• Divergent k-wires
• [Image in source document]
181
* What are 6 techniques for stifle stabilization following mid-substance tear of the CdCL?
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
182
• What are the muscles of the quadriceps mechanism and where do they attach?
• Rectus femoris → ilium cranial to the acetabulum
• Vastus lateralis, medialis, intermedius → GT
183
• What are 8 common anatomic findings associated with MPL in small breed dogs?
• 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
184
• What is thought to be the mechanism of distal femoral varus + internal rotation of the tibia?
• Initial coxa vara → diminished anteversio angle → displacement of quad mechanism medially → abnormal force on distal femoral physis = retards growht of medial femoral conydyle
185
• What is id’d as a risk factor for developing MPL in SOME small breeds?
• Coxa valga
186
* What is the Q angle, and how is it related to grades of MPL vs CCL?
* 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
187
• What are the deformities present in Grade 2 luxation?
• Tibial valgus
• Femora varus
• Internal rotation at the stifle
188
• What are the deformities present in Grade 3/4 luxation?
• Coxa vara
• Femora varus
• Tibia valgus
• Internal rotation of the stifle
189
• What is the risk of MPL following correction for CCL in large breed dogs?
• 0.018%
190
• What are indications for surgical treatment of MPL in small breed dogs?
• 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
191
• What is the surgical treatment for young dogs?
• Two stage treatment
• ST and trochlear chondroplasty first
• Reconstructive techniques when done growing - TTT, DFO, block or wedge trochleoplasty
192
* What are 2 techniques to address MPL in skeletally immature dogs?
* Soft tissue reconstruction/imbrication
* Trochlear chondroplasty
193
• What is the goal for trochleoplasty?
• <50% of patella protruding beyond top
194
• What are the 4 types of trochleoplasties?
• Block
• Wedge
• Abrasion - Sulcoplasty
• Chondroplasty
195
• 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?
• Resurfacing with autogenous periosteal graft → filled with fibrocartilage at 4 wks vs 40 wks in untreated
196
• What trochleoplasty guidelines must be followed for success in wedge recession?
• 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
197
• What are the 2 devices that can be used to form wedge recession?
• Hobby saw
• Sagittal saw
198
• What has been shown to be true about block recession when compared to wedge recession?
• Deeper groove
• Increased patellar articulation
• Recession of a larger percentage of the trochlear surface
• Greater resistance to reluxation
199
• What is TTT correcting?
• Medial displacement of the tibial tuberosity
200
• Where should the osteotomy start and how wide should it be for TTT?
• ½ the width of the tibial tuberosity to the cranial articular margin
• Should start 3-4mm proximal to the insertion of the patellar tendon
201
• What are the fixation techniques for TTT?
• K-wires - one or two
• Pin and TB
202
• In what scenarios is it appropriate for soft tissue recon to be the only procedure that MPL is treated with?
• Young patients that are skeletally immature, underoing stage 1 of a 2 stage treatment
• Traumatic luxations
203
• What 2 tissue layers are commonly released for soft tissue in MPL?
• Medial retinaculum
• Joint capsule - capsulotomy
204
• In grade ¾ w severe malalignment of the quads, what additional tissues can be released?
• Entire quads from femur
• Laterally - vastus lateralis + biceps femoris
• Medially - vastus medialis + caudal head of sartorius
205
• What 2 tissue layers are commonly imbricated for soft tissue in MPL?
• Joint capsule
• Fascia → biceps femoris fascia often
206
• What Are 2 techniques to help correct internal rotation of the tibia, if the animal is skeletally immature?
• Fabellotibial suture
• Fibular head transposition
207
• What are the skeletal abnormalities in large breed dogs with MPL?
• Coxa vara - decreased angle of inclination
• Retroversion of the femur
208
• What does this initial deformity lead to that contributes to MPL?
• 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
209
• What are the proposed causes of MPL in large breed dogs?
• Coxa varum
• Distal femoral varus
• Patella alta or long patellar tendon
• CrCl repair → occurred in 0.018% of stabilization procedures
210
• What are 2 factors associated with MPL in large breed dogs?
• Long patellar ligament, and patella alta
211
• What is associated with MPL in labradors specifically?
• Distal femoral varus
212
• What are the surgical treatments for femoral torsion?
• Closing wedge
• Opening wedge
• Detorsional osteotomy
• Radial osteotomy
• Plate fixation
213
• What are the surgical treatment options to treat CCL rupture + internal torsion of tibia w/MPL in large breeds?
• TPLO w/internal tibial torsion correction
214
* What are surgical treatment options for MPL + CCL rupture in large breeds without internal torsion ?
* TTT and lateral suture
* Tibial closing wedge ostectomy + TTT
* TPLO + TTT
* TPLO + Cranial closing tibial wedge ostectomy + lateral translation of tibial tuberosity segment
215
• What was the reduction in reluxation rates when recession trochleoplasty was performed in addition to TTT?
• 5 fold decrease in reluxation
216
• What is an essential component to G4 MPL correction?
• ALD correction
217
• How is DFO alignment achieved?
• 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
218
• What is the reluxation rate in MPL?
• 8 - 48%
• No reluxation in DFO
219
• What is the major complication rate in G4 MPL repair?
• 24-27%
220
• What are typical deformities seen with LPL (2) and what is a deformity that can be seen in isolation and requires surgical treatment?
• 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
221
• What are 2 factors associated with risk of reluxation?
• Dogs > 20 kg
• Not performing trochleoplasty in addition to TTT
• Luxation and Collateral Ligaments
222
• What are the 3 degrees of ligament injury, and which ones warrant surgery?
• 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
223
• What are the functions of the collateral ligaments in extension? Flexion?
• 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
224
• Which collaterals are taut in extension? Flexion?
• MCL/LCL taut in extension
• MCL taut in flexion only
225
• What can be managed conservatively?
• Single collateral ligament damage can be managed with stabilization for 8 weeks
226
• How is each ligament investigated in a traumatic luxation of the stifle?
• Cranial drawer → CrCl
• Caudal drawer → CdCl
• Varus → LCL
• Valgus → MCL
• Internal rotation → CrCl and some MCL in extension
• External rotation → LCL
227
• What step is performed prior to any attempted joint/ligament reconstruction in a luxated stifle
• 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
228
• What is the technique for repair of avulsed attachments (2)
• Avulsed bone fragments repaired/attached with k-wires
• Bone screws + spiked washer
229
• When tightening the reattachment/suture of collaterals, what position should the stifle be in?
• Extension - prevents over tightening of the suture
230
• What are 2 most common major compilations for stifle joint luxation repair?
• Arthrofibrosis
• Recurrent joint instability
231
• What is the etiology of patella fx in dogs (2) vs cats?
• Dog - direct trauma / complications from TPLO
• Cat - stress fx (from jumping)
232
• What are 3 methods of protecting patellar fracture (or ligament) repairs?
• 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
233
• What is an alternative fixation method for patellar repair other than pin and TB?
• 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
234
• What are 2 treatments for stifle OCD?
• Removal of cartilage lesion via scope vs arthrotomy +/- forage +/- micropicking
235
* What can cause luxation of the LDE?
TPLO, patellar luxation
236
• What are options for acute avulsion of LDE? Chronic?
• 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
237
• How is the best way to achieve an angle of 140 intra-operatively?
• 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
238
• How is the tibial tuberosity reattached and what should be considered when reattaching it?
239
• What % of the femur/tibia should the plate span for arthrodesis of stifle?
• 60-70%
240
• What is a complication that can be seen after arthrodesis?
• OA in hip and tarsus due to abnormal weight bearing
PHII- Ortho
flashcards
Decks in class (38)
# Cards
-
CH38 - MS Tissues75
-
CH39- Bone biomech61
-
CH40- Open fx11
-
CH41 - Internal fx125
-
CH42- ESF100
-
CH43- MIPO29
-
CH44- Bandage/coap34
-
CH45 Delayed/nonunion19
-
CH46 - ALD71
-
CH47- osteomyelitis38
-
CH48- Graft41
-
CH49- Scap fx34
-
CH50- Shoulder97
-
CH51- Humeral fx81
-
CH52- Elbow187
-
CH53- total elbow15
-
CH54- R/U85
-
CH55- carpus/metacarpus74
-
CH56- Pelvic fx70
-
CH57- Hip lux30
-
CH58- hip dysplasia46
-
CH59- Hip dysp sx141
-
CH60 femoral fx114
-
CH61 stifle408
-
CH62- TKR13
-
CH63- Tib/fib72
-
CH64 tarsus/metatarsus91
-
CH65- Amp37
-
CH66/67- Dental136
-
CH68 - arthritis109
-
CH69 - misc ortho conditions116
-
CH70 - muscle/tendon52
-
CH71 - arthroscopy58
-
CH72 - MS neoplasia137
-
CH73- OCD48
-
CH74- GAIT27
-
STIFLE240
-
stifle studies117
