8. Foot and Ankle MCQs

DISCUSSION: The relationship between the distal articular surface of the first metatarsal head and the long axis of the first metatarsal is called the distal metatarsal articular angle. This angle has been validated by Richardson and associates to measure and determine the congruence of the first metatarsophalangeal joint. This angle is critical in determining the appropriate surgical procedure to perform on a patient with a bunion deformity because a congruent joint requires a procedure to maintain congruence of the articular surfaces following osteotomy. Therefore, a chevron becomes a biplanar chevron, and a Lapidus procedure adds a second osteotomy of the distal metatarsal to tilt the metatarsal head into a congruent location. REFERENCES: Coughlin MJ: Juvenile hallux valgus: Etiology and treatment. Foot Ankle Int 1995;16:682-697. Steel MW III, Johnson KA, DeWitz MA, et al: Radiographic measurements of the normal foot. Foot Ankle 1980;1:151-158. Richardson EG, Graves SC, McClure JT, et al: First metatarsal head-shaft angle: A method of determination. Foot Ankle 1993;14:181-185.

Patients with diabetes mellitus should be screened for the presence of protective foot sensation. In the absence of protective foot sensation, patients are at increased risk for the development of neuropathic ulcerations and neuropathic arthropathy. The most reliable screening tool for the presence of protective sensation is the ability to feel the 5.07 Semmes-Weinstein monofilament.

DISCUSSION: A Syme amputation (ankle disarticulation) is a function-preserving amputation option that allows for terminal weight bearing, however strict criteria must be met for a patient to undergo successful Syme amputation. An ankle-brachial index (ABI) less than 0.5 for the posterior tibial artery in a patient with diabetes would be a contraindication for this procedure as success is dependent on the vascular supply of posterior tibial artery to the plantar flap and heel pad.

DISCUSSION: In considering faith-based issues regarding treatment of this patient, the presence of her husband for the office visit would imply an agreement with her decision to have surgery. It also may facilitate her examination. Her role as caregiver, dietary concerns, and cleansing rituals are less important considerations with an outpatient-based procedure. Privacy concerns remain paramount to Muslim women, which include limited exposure during examination, during surgery, and in subsequent follow-up visits.

DISCUSSION: Complications of medial sesamoidectomy include stiffness, claw toe, and hallux valgus. Each sesamoid sits within its respective head of the flexor hallucis brevis tendon. Excision of one sesamoid can result in slack in its flexor hallucis brevis tendon; therefore, it is imperative to preserve or repair the flexor hallucis brevis tendon when removing the medial sesamoid.

DISCUSSION: The patient has a discrete callus that overlies a prominent medial sesamoid. Calluses typically occur in response to increased pressure on the skin. Initial treatment should be directed at reducing local pressure with a felt pad. Sesamoid shaving is indicated if the felt pad fails to provide relief. Sesamoidectomy should be reserved for refractory callus given the potential complications of transfer metatarsalgia or callus and hallux valgus. A first metatarsal dorsiflexion osteotomy is more appropriate for a diffuse callus that fails to respond to nonsurgical management. Cryoablation and topical salicylic acid are appropriate for plantar warts, which have a rougher appearance with multiple, small black spots in the lesion.

DISCUSSIONThe dorsal medial cutaneous nerve arising from the superficial peroneal nerve crosses the inferior extent of a routine extensile surgical exposure to the ankle joint. The extensile anterior incision develops the interval between the tibialis anterior and extensor hallucis tendons, and, although the deep peroneal nerve is lateral and posterior to the extensor hallucis longus, the nerve most at risk during this exposure is the cutaneous branch supplying the dorsal medial foot to the great toe. Ankle replacement surgery is becoming more common; consequently, surgeons must be familiar with this anatomic landmark and risks related to its transection during surgery.The medial plantar nerve is at risk when medial hindfoot incisions are made through theabductor hallucis muscle during tarsal tunnel release and harvest of the flexor hallucis tendon for transfer. The dorsal cutaneous branch of the sural nerve supplies the lateral dorsal

Arthrodesis is indicated for severe bunion and hallux valgus deformities, but particularly with extensive degenerative disease of the first metatarsophalangeal joint. The other bunionectomy procedures have different indications, none of which include symptomatic first metatarsophalangeal degenerative disease.

DISCUSSION: The lateral radiograph shows a traction spur consistent with tendinopathy of the Achilles tendon. There is no displacement of the spur to suggest a rupture of the Achilles tendon, and os trigonum is not seen on the radiograph. The examination findings are not consistent with nerve entrapment.

DISCUSSION: A knee dislocation carries the potential for an arterial injury and has always brought up the question of need for arteriography to rule out this limb-threatening injury. However, arteriography has an inherent complication rate that may compromise the general care of the patient. In over 240 published cases with documented knee dislocations that were evaluated for vascular injury by physical examination (without imaging studies), not a single missed injury was reported, for a 100% negative predictive value (0% false-negative rate). This degree of accuracy at excluding major vascular injury is unsurpassed by the results obtained with arteriography but with no risk involved and a marked savings in time, equipment, and costs. Therefore, the most appropriate first step to rule out vascular injury is examination of the pedal pulses. If there is any doubt about an arterial injury, another option is the ankle-brachial index (ABI). If the ABI is greater than 0.9, the chance of arterial injury is again nonexistent. However, a positive physical examination or an ABI of less than 0.9 is not 100% predictive of an arterial injury; therefore, arteriography is recommended. REFERENCES: Miranda FE, Dennis JW, Veldenz HC, et al: Confirmation of the safety and accuracy of physical examination in the evaluation of knee dislocation for injury of the popliteal artery: A prospective study. J Trauma 2002;52:247-252. Mills WJ, Barei DP, McNair P: The value of the ankle-brachial index for diagnosing arterial injury after knee dislocation: A prospective study. J Trauma 2004;56:1261-1265.

OrthoCash 2020A 76-year old patient underwent partial foot amputation through the talonavicular and calcaneocuboid joints. Besides Achilles tendon lengthening, what additional procedure(s) may be required to prevent the most common post-operative deformity?Posterior capsule releaseAnterior tibialis transfer to the talar neckAnterior tibialis transfer to cuboidFlexor hallucis longus transfer to calcaneusPeroneus brevis transfer to calcaneusCorrent answer: 2Achilles tendon lengthening AND anterior tibialis transfer to the talar neck would be required to prevent equinovarus deformity.Partial foot amputation through the talonavicular and calcaneocuboid joints is also known as the Chopart amputation. Chopart amputation alone is known to result in significant equinovarus deformity. This deformity results in excessive pressure on the anterior wound during gait, causing pain and wound complications. Transfer of the tibialis anterior tendon to talar neck will provide force, and muscle tone, that promotes ankle dorsiflexion. Lengthening of the Achilles tendon will also reduce the equinus moment force across the ankle joint.Dillion et al. examined the gait patterns of partial foot amputees. They found that amputations proximal to the metatarsal heads compromised the normal propulsive function of the foot and ankle. The ideal level of amputation to maintain normal propulsive function was distal to the metatarsal heads (i.e., disarticulating the metatarsophalangeal (MTP) joint).Illustration A is a lateral radiograph showing a Chopart amputation. Incorrect Answers:prevent the equinovarus deformity.OrthoCash 2020A 32-year-old male is involved in a motor vehicle collision and sustains the injury seen in Figure A. What is the most common urological injury associated with this injury pattern?Testicular torsionPosterior urethral tearBladder denervationTesticular ruptureRenal hematomaThe figure shows an anteroposterior pelvic ring injury. The most common urological injury with pelvic ring injuries remains the posterior urethral tear, followed by bladder rupture.Watnik et al notes lower urinary tract (bladder to end of urethra) injuries in up to 25% of patients with this injury. He reports that when contaminated urine communicates with the anterior arch, the possibility of infection exists, and early repair of bladder disruptions with simultaneous anterior arch plating minimizes this risk.Routt et al notes that even with simultaneous treatment of these injuries, complications are common (late stricture in 44%, impotence in 16%, delayed incontinence in 20% of females, anterior deep pelvic infection in 4%). Despite this, they report that early urological repairs are easily performed at the time of anterior pelvic open reduction and internal fixation.OrthoCash 2020A 26-year-old women, 31-weeks pregnant, presents to the emergency department with the injury shown in Figure A. She states the injury occurred while lifting a heavy vacuum five days ago. She suffers from chronic headaches and sleep disturbances. On inspection, there are multiple dorsal and volar bruising over her wrist and upper arm. She is neurologically intact. After closed reduction and immobilizing the arm, what would be the next best step in management of this patient?Diagnostic wrist arthroscopyUrgent MRI wristSkeletal survey radiographsRequest a consultation with social worker in the hospitalUrgent open reduction internal fixationCorrent answer: 4This patient presents with classic features of domestic violence. The most appropriate next step would be consultation with a social worker at the hospital, assess for child and patient safety, and encouraging the patient to seek self-protection.Factors suggestive of domestic violence in the patient include pregnancy, delayed presentation after injury, inconsistent history, multiple bruises and complaints of chronic headache/sleep disturbances. Victims frequently miss days of work and as a result are at risk for losing their jobs. Victims are also more likely to engage in high-risk behavior with sex, drugs, alcohol, smoking, and eating.The AAOS published a document outlining the Orthopaedic Surgeon’s responsibilities in domestic and family violence. Musculoskeletal injuries that should raise a suspicion of a problem include (1) Multiple injuries/fractures; (2) Unusual patterns of injury/fracture; (3) Injuries/fractures of varying ages; (4)Injuries/fractures inconsistent with or disproportional to the history; (5) Multiple injuries treated in different hospital emergency departments or by different providers.Incorrect Answers:OrthoCash 2020A 45-year-old man undergoes open reduction and internal fixation for a comminuted intra-articular humerus fracture . An olecranon osteotomy is performed and subsequently fixed with an intramedullary cancellous screw. Which of the following options in the table shown in Figure A best describes the characteristics of this osteotomy?

Suture-button constructs provide dynamic stabilization of the syndesmosis. The primary biomechanical advantage over rigid screw fixation is that they allow for the maintenance of physiologic micromotion and normal kinematics of the distal tibiofibular joint during the normal gait cycle, while preventing pathologic widening.

Wound healing complications, specifically wound edge necrosis or dehiscence at the apex of the L-shaped flap, are the most common early complication (occurring in up to 10-25% of cases) associated with the extensile lateral approach to the calcaneus. This is largely due to the tenuous blood supply from the lateral calcaneal artery network.

The Lisfranc ligament is a stout interosseous ligament that originates on the lateral aspect of the medial cuneiform and inserts on the medial aspect of the base of the second metatarsal. The "fleck sign" pathognomonic for a Lisfranc injury represents a bony avulsion of this ligament, most commonly pulling off a fragment from the base of the second metatarsal.

The anterolateral distal tibial articular fragment in a pilon or complex ankle fracture is known as the Chaput fragment (or Tillaux-Chaput). It serves as the tibial attachment site for the Anterior Inferior Tibiofibular Ligament (AITFL). The fibular attachment of the AITFL is the Wagstaffe-Le Fort fragment. The posterior tibial fragment (Volkmann's triangle) is the attachment for the Posterior Inferior Tibiofibular Ligament (PITFL).

The primary advantage of the minimally invasive sinus tarsi approach over the traditional extensile lateral approach for calcaneus fractures is a dramatic reduction in soft tissue complications, such as wound dehiscence, flap necrosis, and deep infection. Clinical outcomes and quality of joint reduction have been shown to be comparable between the two approaches in appropriately selected patterns.

The deep posterior compartment contains the flexor hallucis longus (FHL), flexor digitorum longus (FDL), and tibialis posterior, as well as the tibial nerve. Untreated compartment syndrome here leads to weakness in toe flexion and ankle inversion, along with sensory loss on the plantar aspect of the foot (supplied by the tibial nerve). Ankle dorsiflexion and 1st web space sensation are anterior compartment structures (deep peroneal nerve).

Historically, non-operative management of Achilles ruptures with prolonged cast immobilization resulted in higher re-rupture rates compared to surgery. However, modern RCTs (e.g., Willits et al.) have demonstrated that when early functional rehabilitation (early range of motion and weight-bearing in a functional brace) is utilized, the re-rupture rates between operative and non-operative groups are essentially equal, while surgery carries a higher risk of wound complications.

In a Pronation-External Rotation (PER) injury, the sequence begins medially. Stage 1 is a medial malleolus fracture or deltoid ligament rupture, followed by AITFL rupture (Stage 2), high fibular fracture (Stage 3), and PITFL rupture (Stage 4).

The artery of the tarsal canal is a branch of the posterior tibial artery and provides the dominant blood supply to the talar body. It anastomoses with the artery of the tarsal sinus to form a vascular sling inferior to the talar neck.