Trauma Principles (Complete)

Question 1

What are the principles of external fixation?

Answer 1

•Two general types:

• Monolateral/unilateral external fixation– frames are positioned on one side of the limb
• Circular external fixation

•Monolateral/Unilateral External Fixation

• Components = pins, clamps, connecting rods
• Stability is increased by:
  
  • Larger diameter half pins (most important)
  • Increasing the number of pins
  • Increasing pin spread in each fragment
  • Minimize the pin-fracture site distance
  • Minimize the bone-connecting rod distance
  • Place pins out of plane to one another
  • Adding an additional connecting bar in parallel (‘double stacking’)
  • Increase the stiffness of the connecting rod (increase diameter, carbon fibre > stainless > titanium)
  • Add a second unilateral fixator for multiplanar fixation
• Pin mechanics
  
  • Pin stiffness increases with increasing diameter
    
    • Too large = increases risk of fracture (pin >30% of bone diameter substantially increases the risk of pin site fracture)
    • Too small = increases micromotion at pin-bone interface (leading to failure)
    • Pin diameter guidelines:
      
      • Femur – 5 or 6 mm
      • Tibia – 5 or 6 mm
      • Humerus – 5 mm
      • Forearm – 4 mm
      • Hand, Foot – 3 mm
    • Half pin vs. transfixion (full) pins
      
      • Half pin protrudes from bone/skin from one side, has bicortical fixation
      • Transfixation pins protrudes from bone/skin on two sides, has bicortical fixations, has higher risk of neurovascular injury
    • Principles of insertion
      
      • Avoid heat necrosis (sharp drill bits, frequent pauses, clear flutes, etc)
      • Protect soft tissues
      • Avoid neurovascular structures and joints

Question 2

What are the pin placement locations in respective bones for external fixation?

[J Am Acad Orthop Surg 2015;23:683-690]

Answer 2

oHumerus = 5mm pins placed anterolaterally (avoid axillary n, radial n, and olecranon fossa)

oUlna = 4mm pin proximally and 3mm pin distally along subcutaneous border (preferred over radius)

oRadius = 4mm pin along radial border (posterior to radial artery and superficial radial n)

o2nd metacarpal = 3mm pin entering radial border of 2nd MC base

• Flex fingers at time of pin insertion, avoids entrapment of extensor tendon which would prevent finger flexion

oFemur = 5mm pins placed anterolaterally or direct lateral

oTibia = 5mm pins placed anteromedial

oCalcaneus = 5mm pin placed medial to lateral in safe zone (posterior to the halfway point from the posteroinferior calcaneus to the inferior medial malleolus and posterior to the one-third mark from the posteroinferior calcaneus to the navicular tuberosity)

• Structures at risk = calcaneal nerve (medial), sural nerve (lateral)

oFoot = medially into the talar neck, cuneiforms, or first metatarsal base, or laterally into the cuboid or fifth metatarsal base. For cuneiform pin placement, the pin should enter the dorsal half of the medial cuneiform

Question 3

What are 2 types of traction?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 3

1. Skin traction - pulling force is applied to the skin and soft tissue of the limb using adhesive traction tape, halters, belts, or boots
2. Skeletal traction involves a more invasive and direct pull on a bone through surgically placed pins, wires, or tongs

Question 4

What are the 3 most common sites for lower extremity skeletal traction?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 4

1. Distal femur

• Indications
  
  • Acetabular fractures not involving the weightbearing dome
  • Pelvic fractures with a displaced hemipelvis
  • Adult proximal third femur fracture
  • Pediatric femoral shaft fracture (90/90 traction)
  • Any contraindication to a proximal tibia pin
• Pin location
  
  • Placed from medial to lateral
  • >0.7 cm proximal to the adductor tubercle near the metaphyseal flare
    
    • Avoids joint and femoral artery in the adductor hiatus

2. Proximal tibia

• Indications
  
  • Femoral fractures located in the distal 2/3 of the shaft
• Contraindications
  
  • Ligamentous knee injuries
  • Tibial plateau fractures
  • TKA with a long stemmed implant
• Pin location
  
  • Placed from lateral to medial
  • 2.5cm posterior and 2.5cm distal to the tibial tubercle parallel to the joint

3. Calcaneus

• Indications
  
  • Tibial shaft fractures
  • Distal tibia fractures
  • Subtalar dislocation
  • Intra-op distraction during ankle arthroscopy
• Pin location
  
  • Placed medial to lateral
  • Safe zone is 3.1cm radius around the posterior inferior calcaneus
    
    • Calcaneal nerve (medial) and sural nerve (lateral) at risk

Question 5

Described the general technique for application of skeletal traction

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 5

1. Local anaesthetic infiltrated into skin, soft tissues, and periosteum of both entry and exit sites

• Sharp incision of skin at entry site
• Blunt dissection of underlying soft tissue with blunt snap
• Insert either K-wire (smooth) or Steinmann pin (threaded)
  
  • Pin diameter should be <30% of the bone diameter
• Pass pin through near and far cortex until tenting of the soft tissue at the exit site
• Incise the skin then advance the pin to final position.

2. Apply traction bow with padding to adjacent skin.
3. The weights are determined by the age, bone quality, and body habitus of the patient as well as the traction placement
   * Bowline, cow-hitch and slipknot are most effective knots for suspending weights
4. Recommend post reduction xrays 6-12 hours after application to allow muscles to relax.

Question 6

What are the advantages and disadvantages of using a threaded pin/wire (vs smooth) for skeletal traction?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 6

Advantages:

• Less likely to loosen
• Easier to advance through bone

Disadvantages:

• More likely to bend
• More traumatic to soft tissues at entry/exit sites

***A centrally threaded pin may be allow for easier advancement with less trauma to soft tissues

Question 7

What are the risks of a transcortical (i.e. unicortical) traction pin?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 7

1. Generate heat (thermal injury)
2. Loosen
3. Prone to infection

Question 8

What are the indications for skeletal traction in acetabular and pelvic fractures?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 8

1. Mainly a temporizing measure until definitive surgery
2. Immediate treatment of acetabular fractures with:

• Incarcerated intra-articular fragments
• Persistent subluxation of the femoral head
• ***Injuries often associated with posterior wall fractures

3. Medialization of the femoral head secondary to quadrilateral plate disruption

• Traction pin should be placed in distal femur
• Only use trochanteric pins intraop, due to increased infection risk with prolonged use

4. Pelvic ring injuries with complete disruption of the posterior sacroiliac complex, as seen in vertical shear injuries, may require skeletal traction to help reduce the displaced hemipelvis.
5. Traction may also be an adjunct for a combined acetabular and pelvic ring injury that has been temporarily stabilized with an external fixator.

Question 9

What are the contraindications to skeletal traction in acetabular and pelvic fractures?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 9

1. Nondisplaced acetabular fractures that are stable at fluoroscopic stress examination
2. Acetabular fractures through the weightbearing dome (irreducible with traction)

Question 10

What are the indications for skeletal traction in femoral neck and hip dislocations?

[J Am Acad Orthop Surg 2016;24:600-606]

Answer 10

None

• No improvements in pain or intra-op reduction
• A prospective pilot study used digital subtraction
  angiography to assess the blood supply to the femoral head before and after traction.
  
  • The application of 3-5 kg of traction significantly diminished the flow within the retinacular vessels that supply the femoral head
  • Authors concluded that traction is a possible risk factor for the development of AVN

Question 11

What are the definitions of nonunion and delayed union?

[Rockwood and Green 8th ed. 2015]

Answer 11

1. Nonunion = fracture has failed to heal in the expected time and is not likely to heal without new intervention
2. Delayed union = fracture has failed to heal in the expected time but still has the potential to heal without further intervention

Question 12

When is a fracture of a long bone considered nonunion?

[JAAOS 2013;21:538-547]

Answer 12

1. Lack of healing 6-9 months following injury
   * Delayed union after 4 months
2. No interval healing on two consecutive radiographs 6-8 weeks apart

Question 13

What are factors that contribute to nonunion?

[Rockwood and Green 8th ed. 2015]

Answer 13

1.Fracture factors

• A. Fracture location
  
  • Anatomic sites with limited or watershed vascular supply (eg. diaphysis of long bones, talar neck, scaphoid waist, femoral neck, proximal meta-diaphysis of 5th MT)
• B. High-energy fractures
  
  • Comminution
  • Bone loss
  • Periosteal stripping
  • Soft tissue stripping
• C. Open fracture
  2. Host factors
• Smoking and nicotine products
• Diabetes
• Peripheral vascular disease
• Medications – steroids, NSAIDs, chemotherapy, bisphosphonates
• Poor nutrition – protein, calcium, Vit D
• Osteoporosis
• Advanced age
• Immunosuppression
• Radiation exposure
  3. Surgeon factors
• Inadequate fixation stability
• Soft tissue disruption

4.Infection

Question 14

How are nonunions classified?

[Rockwood and Green 8th ed. 2015]

Answer 14

1. Septic nonunion
2. Atrophic nonunion (poor stability, poor biology)

• A. Radiographic features – absence of any bony reaction
• B. Fracture has inadequate healing response (due to above factors)
• C. Treatment requires biologic stimulus – bone autograft, BMP, debridement of nonviable bone ends to bleeding bone

3. Hypertrophic nonunion (poor stability, good biology)

• A. Radiographic features – abundant callus formation with a dark line
• B. Fracture has adequate healing response but inadequate stability
• C. Treatment requires rigid stabilization

4.Oligotrophic nonunion (poor reduction)

• A. Radiographic features – minimal callus formation
• B. Fracture healing has reduced healing response
• C.Treatment requires mechanical compression or bone grafting of defects

5.Pseudoarthrosis

• A. Fracture site has excessive motion resulting in formation of a pseudocapsule containing fluid
• B. Treatment requires stabilization and usually biological stimulus

Question 15

What are the treatment options for non-union?

[Rockwood and Green 8th ed. 2015]

Answer 15

Nonoperative:

1. Indirect intervention
   
   • Smoking cessation
   • Nutrition optimization
   • Discontinue offending medications
   • Optimize endocrine and metobolic disorders
2. Direct intervention
   • Weight bearing
   • Cast or orthosis
   • Electromagnetic stimulation
   • Ultrasound stimulation (LIPUS – low intensity pulsed ultrasound) – better evidence
   • Parathyroid hormone (PTH)

Operative:

1. Plate and screw fixation
2. Reamed exchange nailing
3. Nail dynamization
4. Circular ring external fixator
5. Arthroplasty for periarticular nonunions in the elderly
6. Amputation
7. Arthrodesis
8. Fragment excision in certain locations (eg. ulnar styloid, olecranon)
9. Resection arthroplasty (eg. radial head nonunion, proximal pole of scaphoid)

Question 16

What are the autograft options for nonunion treatment?

[J Orthop Trauma 2018;32:S52–S57)]

Answer 16

1. ICBG (iliac crest bone graft)
   * Yield = 30cc
2. RIA (reamer-irrigator-aspirator)
   * Yield = up to 60cc

Question 17

What is the management of an infected nonunion?

[J Orthop Trauma 2018;32:S7–S11)]

Answer 17

1. Diagnosis -.WBC, ESR, CRP (most accurate predictor)
2. Initial surgical stage

• A. Removal of all loose or chronically infected hardware
• B. Debridement of all infected or nonviable bone or soft tissue
• C. Minimum 3-5 deep tissue biopsies for culture and sensitivity
• D. Revision of fracture fixation
  
  • Temporary fixation – ex-fix, casting, antibiotic nail
  • Permanent fixation – plate fixation, IM nail, locked antibiotic nail
• E. Placement of local antibiotic
  
  • Antibiotic nail, antibiotic impregnated osteoconductive pellets (eg. Osteoset T), antibiotic powder, antibiotic cement beads, antibiotic cement spacers (combined with induced membrane)
    
    3. Interim culture specific antibiotics and monitoring clinically and serologically for resolution of infection
    4. Second surgical stage
• A. Definitive fracture fixation (if temporary fixation was used)
• B. Reconstruction of the bone defect

Question 18

What is the definition of critical bone defect?

[J Orthop Trauma 2018;32:S7–S11)]

Answer 18

1. Defect that will not heal spontaneously despite surgical stabilization
2. Requires surgical intervention

Question 19

What is the difference between a nonunion and critical bone defect?

[J Orthop Trauma 2018;32:S7–S11)]

Answer 19

1. Nonunion has impaired biology and/or inadequate stability
2. Critical bone defect has adequate biology and stability but an inability to replace the substantial bone loss

Question 20

What is the critical size for a bone defect?

[J Orthop Trauma 2018;32:S7–S11)]

Answer 20

Circumferential loss >50% or length >2cm

• Variable depending on:
  
  • Location
  • Soft tissue involvement
  • Patient age
  • Comorbidities

Question 21

What are the surgical options to manage critical segmental bone defects and what size defects are the options amenable to?

[JAAOS 2015;23:143-153] [J Orthop Trauma 2018;32:S7–S11)]

Answer 21

1. Induced membrane technique (Masquelet) >10cm (5-24)
2. Distraction osteogenesis 5-10cm
3. Acute limb shortening 1-3cm
4. Vascularized fibula transfer 10-20cm
5. Amputation

Question 22

What are the 3 main benefits of the Masquelet technique?

[JAAOS 2015;23:143-153]

Answer 22

1. “Priviledged compartment” limits autograft resorption
2. Maintains the defect space for delayed bone grafting
3. Induced membrane is rich in growth factors which improve graft consolidation

Question 23

What is the function of the PMMA spacer in Masquelet Technique?

[J Orthop Trauma 2018;32:S7–S11)]

Answer 23

1. Induces formation of biologically active pseudomembrane
2. Maintains space for bone graft
3. Delivers antibiotics

Question 24

What is the function of the induced membrane in Masquelet Technique?

[J Orthop Trauma 2018;32:S7–S11)]

Answer 24

1. Provides vascularization of bone graft
2. Prevents graft resorption
3. Provides growth factors which promote graft consolidation

Question 25

Describe the Masquelet technique [J Orthop Trauma 2018;32:S7–S11)]

Answer 25

Two stage procedure 1. Stage 1 * Debridement of bone and soft tissue * Stabilization with external or internal fixation * Placement of PMMA spacer (with or without antibiotics) 2. Stage 2 * 6-8 weeks later the membrane is incised * The PMMA spacer is removed and the preserved defect is bone grafted * Autograft is gold standard * RIA +/- allograft or bone substitute (do not exceed 3:1 ratio of allograft to autograft)

Question 26

What are the two strategies for distraction osteogenesis? [JAAOS 2015;23:143-153] [J Orthop Trauma 2018;32:S7–S11)]

Answer 26

1. Acute or gradual shortening and compression at the defect site * Followed by corticotomy and lengthening at a separate metaphyseal location 2. Bone transport * Performed by applying a frame, making a corticotomy and transporting a segment across the defect at a rate of 1mm per day until it reaches the docking site and is compressed * A secondary autografting at the docking site may be necessary if consolidation is incomplete

Question 27

What is the main limiting factor in acute limb shortening?

Answer 27

Vessel kinking with shortening beyond 3-5cm

Question 28

What is heterotopic ossification? [JBJS 2015;97:1101-11]

Answer 28

Formation of ectopic lamellar bone in soft tissues

Question 29

What are the risk factors for HO formation? [JBJS 2015;97:1101-11][JOT 2012; 26(12): 684–688]

Answer 29

1. Male 2. Traumatic brain injury 3. Spinal cord injury * HO commonly forms caudad to the level of injury 4. Burns * \>20% BSA significantly increases risk 5. Delay in treatment 6. Revision surgery 7. Certain injury locations/surgeries * Acetabulum, THA, elbow fractures, distal humerus 8. Ankylosing spondylitis/DISH 9. Blast injuries

Question 30

What are the classification systems for HO of the hip and elbow? [JBJS 2015;97:1101-11]

Answer 30

1. Brooker Classification System for HO at the hip * Class 1 - Islands of bone within soft tissues of the hip * Class 2 - Bone spurs in the pelvis or femur but with ≥1cm between bone surfaces * Class 3 - Bone spurs within the pelvis or femur with \<1cm between bone surfaces * Class 4 - Ankylosis of the hip 2. Hastings and Graham Classification System System for HO at the Elbow * Class I - radiographic evidence without functional deficit * Class IIA - radiographic evidence with limitation in flexion-extension axis * Class IIB - radiographic evidence with limitation in pronation-supination axis * Class IIIA - ectopic bone formation and ankylosis of joint in flexion-extension axis * Class IIIB - ectopic bone formation and ankylosis of joint in pronation-supination axis * Class IIIC - ectopic bone formation and ankylosis of joint in pronation-supination and flexion-extension axes

Question 31

What is the workup for the evaluation of HO? [JBJS 2015;97:1101-11] [JOT 2012; 26(12): 684–688]

Answer 31

1. History and physical examination (may be asymptomatic) 2. Radiographs 3. CT scan – preoperative planning 4. MRI – preoperative planning if NV structures in close proximity 5. Bone scan * Can detect HO earlier

Question 32

What are the available HO prophylaxis methods? [JBJS 2015;97:1101-11] [JOT 2012; 26(12): 684–688]

Answer 32

1. NSAIDS * Typically, indomethacin 25mg po TID for 6 weeks * Disadvantages: * Nonunion * Patient noncompliance * GI upset 2. Radiation * Typically single fraction dose 700-800cGy given 24 hours preop to 48-72 hours postop * Disadvantages: * Cost * Malignancy risk * Soft tissue contracture * Delayed wound healing * Nonunion * Inhibited ingrowth of pressfit implants

Question 33

What is the indication for surgical management of HO? [JBJS 2015;97:1101-11] [JOT 2012; 26(12): 684–688]

Answer 33

1. Persistent symptomatic HO despite nonoperative management 2. Others: * Restricted range of motion (primary or secondary athrofibrosis or ankylosis) * Pain * Nerve entrapment * Skin ulceration * Difficulties with prosthesis fitting/use

Question 34

What is the workup and timing of HO excision? [JBJS 2015;97:1101-11] [JOT 2012; 26(12): 684–688]

Answer 34

1. Traditionally * Delaying surgical intervention until alkaline phosphatase levels normalize and the heterotopic bone is mature on radiographs and quiescent on bone scan. 2. Contemporary * Proceed once no further improvement with nonoperative management, fractures have healed and radiographs are stable * Rule out other causes of pain (nonunion, infection, arthritis, etc) * Images should include: * Radiographs * CT with 3D recon * +/- MRI if close to NV structures * Generally, prophylactic radiation preferred

Question 35

What are the general timing recommendations for surgical excision of HO? [JBJS 2015;97:1101-11]

Answer 35

1. Traumatic HO – 6-9 months 2. SCI related HO – 12 months 3. TBI related HO – 18 months

Question 36

What are the principles and techniques to achieve a successful arthrodesis?

Answer 36

1. Optimize patient condition * Address modifiable risk factors (smoking, malnutrition, diabetes control, vascular intervention, avoid NSAIDs) 2. Meticulous handling of soft tissue 3. Joint preparation * Denude cartilage, expose bleeding subchondral bone 4. Obtain maximal bony contact 5. Bone graft as necessary 6. Select arthrodesis position 7. Obtain compression and rigid internal fixation

Question 37

What are the causes of acute compartment syndrome? [JAAOS 2005;13:436-444]

Answer 37

1. Fracture 2. Soft-tissue trauma without fracture 3. Intracompartmental bleeding 4. Tight casts, dressings or external wrappings 5. Thermal injury 6. Burn eschar 7. Extravasation of IV infusion 8. Venous obstruction 9. Reperfusion injury following prolonged ischemia 10. Penetrating trauma

Question 38

What are the indications for compartment pressure measurements? [JAAOS 2005;13:436-444]

Answer 38

1. One or more symptoms of compartment syndrome with confounding factors * Eg. neurologic injury, regional anaesthesia, undermedication 2. No symptoms other than increased firmness or swelling in the limb in an awake, alert patient receiving regional anaesthesia for postoperative pain control 3. Unreliable or unobtainable examination with firmness or swelling in the injured extremity 4. Prolonged hypotension and a swollen extremity with equivocal firmness 5. Spontaneous increase in pain in the limb after receiving adequate pain control

Question 39

What are the 6 P’s of compartment syndrome? [JAAOS 2005;13:436-444]

Answer 39

1. Pain, pressure, pulselessness, paralysis, paresthesia, and pallor * Pain out of proportion to the injury, aggravated by passive stretching of muscle groups in the corresponding compartment, is one of the earliest and most sensitive clinical signs of compartment syndrome

Question 40

Intracompartmental pressure measurment thresholds for diagnosis include? [J Am Acad Orthop Surg 2013;21:657-664]

Answer 40

1. Absolute pressure measurements ≥30mmHg 2. Pressure measurements within 30mmHg of the diastolic pressure

Question 41

How many compartments in the arm?

Answer 41

1.Two – anterior and posterior

Question 42

What is the appropriate management of arm compartment syndrome?

Answer 42

2 incision fasciotiomy * Anterior and posterior compartment release through two separate midline longitudinal incisions

Question 43

How many compartments are in the forearm? [J Am Acad Orthop Surg 2011;19:49-58]

Answer 43

1. Three – volar, dorsal and mobile wad (volar is the most common compartment involved in the upper extremity)

Question 44

What is the appropriate management of forearm compartment syndrome? [J Am Acad Orthop Surg 2011;19:49-58]

Answer 44

1. First release the volar compartment – this often decompresses the dorsal compartment and mobile wad 2. Volar compartment release * A. Longitudinal incision just radial to FCU – extends radially at the antecubital fossa curving up the lateral arm, extends to the midline at the wrist * B. Release the transverse carpal ligament, lacertus fibrosis, and fascia over the deep muscles by retracting FCU ulnar and FDS radial 3. Dorsal compartment and mobile wad release * A. Longitudinal incision starting 2cm distal to the lateral epicondyle extending to the midline of the wrist, deep dissection is between ECRB and EDC

Question 45

How many compartments are in the hand? [J Am Acad Orthop Surg 2011;19:49-58]

Answer 45

Ten * 4 dorsal interossei * 3 volar interossei * adductor pollicis * thenar * hypothenar

Question 46

What is the appropriate management of hand compartment syndrome? [J Am Acad Orthop Surg 2011;19:49-58]

Answer 46

4 incision fasciotomy * A.Dorsal longitudinal incisions over the 2nd and 4th metacarpal * B.Longitudinal incisions at the junction of the glaborus and non-glaborus skin over the thenar and hypothenar eminences

Question 47

How many compartments are in the thigh?

Answer 47

Three – anterior, posterior, medial

Question 48

What is the appropriate management of thigh compartment syndrome?

Answer 48

Single incision fasciotomy * A. Direct lateral extensile incision, fascia lata is incised in line with incision and vastus lateralis can be elevated to allow release of the posterior compartment * B. Rarely a separate medial incision is needed to release the adductor compartment

Question 49

How many compartments are in the lower leg?

Answer 49

Four – anterior, lateral, superficial posterior, deep posterior

Question 50

What is the appropriate management of lower leg compartment syndrome? [JBJS Essent Surg Tech. 2015 Dec 23; 5(4): e25.]

Answer 50

1. 2 incision fasciotomy (although 1 incision has been described through a single lateral incision) * A. Anterolateral incision * i. Longitudinal incision ~2cm anterior to the fibula centered over the anterior intermuscular septum approximately 15cm in length, elevate full thickness skin flaps ~2-3cm anterior and posterior * ii. Release the anterior compartment with fascial incision ~1cm anterior to the intermuscular septum * iii. Release the lateral compartment with fascial incision ~1cm posterior to the intermuscular septum * iv. Structure at risk = superficial peroneal nerve * B. Posteromedial incision * i. Longitudinal incision ~2cm posterior to the medial border of the tibia approximately 15cm in length * ii. Release the deep posterior compartment along the posterior border of the tibia * iii. Release the soleus origin off the tibia (aka. Soleus bridge) * iv. Release the superficial posterior compartment with a separate fascial incision ~2cm posterior to the incision for the deep posterior compartment * v. Structure at risk = saphenous vein and nerve

Question 51

How many compartments are in the foot?

Answer 51

The most accepted number is 9 [J Am Acad Orthop Surg 2013;21:657-664] * Medial, lateral, superficial central, deep central (calcaneal), 4 interosseous, adductor hallucis compartment

Question 52

What are the complications of untreated foot compartment syndrome? [J Am Acad Orthop Surg 2013;21:657-664]

Answer 52

1. Ischemic contracture (claw toe [most common], hammer toe, pes cavus) 2. Chronic pain 3. Insensate foot 4. Neuropathic pain 5. Neuropathic ulceration 6. Foot and ankle stiffness

Question 53

What is appropriate management of foot compartment syndrome? [J Am Acad Orthop Surg 2013;21:657-664]

Answer 53

1. Initial management * Remove constrictive dressings, elevate foot, prevent systemic hypotension, serial exam and compartment pressure measurements 2. Definitive management once diagnosis established * A. 3 incision fasciotomy * i. Medial incision (6cm long, 4cm anterior to posterior heel and 3cm superior to plantar surface) * ii. Two dorsal incisions (1st webspace and 4th webspace) * B. Fix forefoot and midfoot fractures at time of fasciotomy, delay fixation of calcaneal fractures until soft tissues allow * C. Dorsal incisions closure with split thickness skin grafts 5-7 days after fasciotomy * D. Medial incision primary or delayed closure

Question 54

Following a fasciotomy how are the wounds best managed? [J Am Acad Orthop Surg 2011;19:49-58]

Answer 54

1. Do not close the wound, leave open with sterile wet-to-dry dressings * Consider VAC or shoelace closure [CORR trauma] 2. ~48 hours later repeat irrigation and debridement and remove necrotic tissues * A. Consider primary delayed closure at this time if no necrotic tissue, or split thickness skin graft if cannot be closed * B. If necrotic tissue present perform I&D, leave wound open and return in ~48 hours for repeat I&D 3. If wound cannot be closed primarily consider vacuum-assisted wound closure – may allow primary closure later * If cannot be closed primarily perform split thickness skin grafting

Question 55

What are the general principles of tendon transfer? [J Am Acad Orthop Surg 2013;21:675-684][ASSH Manual of Hand Surgery]

Answer 55

1. The donor tendon must be expendable (minimal loss of function) 2. The strength of the donor tendon decreases by one grade following transfer * Donor muscles must have 5/5 or 4/5 strength 3. The tendon excursion of the donor must be sufficient to restore lost function of the recipient tendon * Difficult for a muscle to replace one with greater excursion * Excursion of muscles available to transfer: * \*\*\*3-5-7 rule * Wrist extensors and flexors = 30mm * ECRL, ECRB, ECU, FCR, FCU * Digital extensors = 50mm * EDC, EIP, EDQ, EPL * Digital flexors = 70mm * FDS 4. The direction of pull of the recipient tendon should be in line with the donor 5. A single transferred tendon should perform a single function 6. Transferred tendon should cross only one joint 7. Tendon transfers should not be placed through heavily scarred soft-tissue planes (limits excursion) * Allow scars to mature or pass through healthy tissue 8. The joints controlled by the transferred tendon should have near full passive ROM 9. Tendons with in-phase functions should be used preferentially

Question 56

What are the simplified principles of tendon transfer?

Answer 56

1. Supple joint 2. Tissue equilibrium 3. Donor tendon: * Expendable * In line * In phase * Synergistic * Serve one function * Cross one joint * Adequate strength * Adequate excursion \*\*\*Rule of 13 S's In a Sensible patient, I will transfer a * Strong, Sacrificeable, Synergistic tendon with Sufficient excursion * Straight through a Scarless, Stable bed, Subcutaneously * across a Supple, Sensate joint * to achieve a Single function by Securing distally Patient * Sensible Tendon * Strong (will lose 1 grade of power) * Sacrificeable * Synergistic * Sufficient excursion Surgery * Straight * Subcutaneous * Straight pull * Secure distally * Single function Joint * Supple * Sensate * Scarless

Question 57

What is the recommended method of joining donor to recipient tendon in a tendon transfer? [JAAOS 2013;21:675-684]

Answer 57

Pulvertaft weave * Minimum of 3 weaves is recommended * Slits in the recipient tendon are made at 90° to each other * Mattress suture is made at each pass through the recipient tendon

Question 58

What is the difference between a high and a low radial nerve palsy? [JAAOS 2013;21:675-684]

Answer 58

1. High radial nerve palsy = injury proximal to elbow joint involving the radial nerve proper * Motor deficits = inability to extend the wrist and fingers at the MCP joints * Wrist drop and decreased grip strength * Sensory deficits = increased two-point discrimination or complete anesthesia over the dorsum of the first web space 2. Low radial nerve palsy = injury distal to the elbow joint involving the PIN * Motor deficits = inability to extend fingers at the MCP * Wrist extension has substantial radial deviation * ECRL functions but ECU is lost * Sensory deficits = none

Question 59

What are the tendon transfers for radial nerve palsy? [JAAOS 2013;21:675-684]

Answer 59

1. Wrist extension – PT to ECRB * ECRB preferred over ECRL as it is more central 2. Finger extension – FCR to EDC * FCR routed either through the IOM or radially around forearm 3. Thumb extension – PL to EPL * FCR of ring in absence of PL

Question 60

What is the difference between a high and low median nerve palsy? [JAAOS 2013;21:675-684]

Answer 60

1. High median nerve palsy = injury proximal to the elbow joint * Motor deficits: * Inability to flex thumb, DIP and PIP joints in index and middle finger * Loss of thumb opposition * Weakened forearm pronation * Wrist flexion intact due to FCU * Sensory deficits: * Palmar surface of thumb, index, middle and radial half of ring finger 2. Low median nerve palsy = injury distal to the elbow joint * Motor deficits = loss of thumb opposition (weak APB)

Question 61

What are the tendon transfers for median nerve palsy? [JAAOS 2013;21:675-684] [ASSH Manual of Hand Surgery]

Answer 61

1. Thumb opposition – opponensplasty = EIP/FDS ring/PL to APB (Bunnels) * High median nerve – EIP * Low median nerve – FDS ring 2. Thumb flexion – BR to FPL 3. Index/middle finger flexion – FDP ring and small to FDP index and middle side-to-side transfer

Question 62

What is the difference between high and low ulnar nerve palsy?

Answer 62

1. High ulnar nerve palsy = injury proximally at the elbow * Motor deficits = FCU, FDP of small and ring, intrinsics * Clawing is less prominent due to loss of FDP of small and ring * Sensory deficits = ulnar palm and small and ulnar half of ring 2. Low ulnar nerve palsy = injury at the wrist * Motor deficits = intrinsic paralysis * Clawing * Pinch and grip weakness * Lack of finger abduction/adduction * Sensory deficits = small and ulnar half of ring

Question 63

What are tendon transfers for ulnar nerve palsy? [ASSH Manual of Hand Surgery]

Answer 63

1. Power pinch weakness – adductorplasty = ECRB with graft/(FDS long finger) to adductor pollicis 2. Clawing – FDS ring to lateral bands (radial bands of ring and small) OR (Zancolli procedure) 3. Index abduction – EIP to 1st dorsal interosseous 4. Loss of FDP 4/5 – Side-to-side ring/small FDP to index/middle FDP

Question 64

Tendon transfers for musculocutaneous nerve palsy? [ASSH Manual of Hand Surgery]

Answer 64

Elbow flexion * Pectoralis major sternocostal head to biceps tendon * Elongation with fascia lata autograft * Latissimus dorsi to biceps tendon * Steindler flexorplasty * Flexor pronator mass transfer 5cm to anterior humeral shaft * Triceps transfer to biceps tendon

Question 65

What are tendon transfers for axillary nerve palsy? [ASSH Manual of Hand Surgery]

Answer 65

Shoulder external rotation * L’Episcipo procedure – latissimus dorsi and teres major transfer to posterolateral GT * Latissimus dorsi transfer to GT (without teres major)

Question 66

What are tendon transfers for tendon ruptures? [AAOS Comprehensive Review, 2014]

Answer 66

Differs in that innervation is maintained to surrounding muscles so local/intracompartment transfers are possible 1. Extensor tendons * EIP to EPL * 3 incision technique (over 2nd MCP, radiocarpal joint and STT joint levels) * End-to-side transfers of EDC tendons 2. Flexor tendons * FDS ring to FPL (Mannerfelt)

Question 67

What is the order of function loss and recovery in a peripheral nerve injury?

Answer 67

1. Order of loss: * Motor * Proprioception * Touch * Temperature * Pain and sympathetic 2. Order of recovery = reverse (motor last to recover)

Question 68

What are the nerve structures from deep to superficial?

Answer 68

* Axon * Myelin * Endoneurium * Fascicle * Perineurium * Epineurium

Question 69

What is Wallerian degeneration?

Answer 69

After transection of the axon the distal axon and myelin degenerates along with the proximal axonal segment to the next adjacent node of Ranvier

Question 70

What are the classification systems for peripheral nerve injuries?

Answer 70

1.Seddon classification * Neuropraxia = segmental myelin damage with an intact axon * Coincides with Sunderland Type 1 * Axonotmesis = axonal injury where the connective tissue and nerve continuity remain intact * Coincides with Sunderland Type 2-4 * Neurotmesis = complete physiological and anatomical transection of both axons and connective tissue * Coincides with Sunderland Type 5 2. Sunderland classification (histological) * Increasing grades based on the tissue injured * Type 1 - local myelin damage usually secondary to compression * Type 2 - loss of continuity of axons * Endoneurium, perineurium, and epineurium intact * Type 3 - loss of continuity of axons and endoneurium * Perineurium and epineurium intact * Type 4 - loss of continuity of axons, endoneurium and perineurium * Epineurium intact * Type 5 - complete physiologic disruption of entire nerve trunk

Question 71

What is the timeline for functional recovery of a nerve injury?

Answer 71

1. Rate of axonal regeneration is 1mm/day 2. 12–18 month window for muscle reinnervation to occur in order to achieve functional recovery before irreversible motor end plate degeneration occurs