8. Foot and Ankle MCQs

DISCUSSION: The radiograph and MRI scan show elongation and fragmentation of the os peroneum. Although casting, orthoses, and steroid injection may relieve symptoms, excision of the os peroneum and primary repair when necessary, with or without tenodesis of the peroneus longus to the peroneus brevis, have been shown to produce excellent results.

DISCUSSION: The patient has a calcaneonavicular tarsal coalition. Symptoms of calcaneonavicular coalitions typically are seen between the ages of 10 and 14 years. The cause of pain has not been clearly established. It has been postulated that the coalition stiffens with maturity and microfractures can result, producing pain. Resection of a calcaneonavicular coalition generally has been associated with a satisfactory result. Soft-tissue interposition, most commonly using the extensor digitorum brevis muscle, appears to be helpful. A hindfoot arthrodesis (usually triple) would be reserved if coalition resection proves to be unsuccessful.

DISCUSSION: The radiographs show a displaced ankle fracture with widening of the syndesmosis. Open reduction and internal fixation is indicated with fixation of the mortise with syndesmotic screws.

DISCUSSION: The patient has instability of the peroneal tendon. The superior peroneal retinaculum is the primary retaining structure preventing peroneal subluxation. It is a thickening of fascia that arises off the posterior margin of the distal 1 to 2 cm of the fibula and runs posteriorly to blend with the Achilles tendon sheath. The inferior peroneal retinaculum attaches to the peroneal tubercle of the calcaneus and is not involved in this pathology. A deficient groove in the posterior distal fibula may also be a contributing factor in the development of the condition. REFERENCE: Maffuli N, Ferran NA, Oliva F, et al: Recurrent subluxation of the peroneal tendons. Am J Sports Med 2006;34:986-992.

DISCUSSION: The radiograph shows a complete extrusion of the talus. Reimplantation of the talus after wound debridement has been reported to be safe and successful, and provides for flexibility with any future reconstructive procedures. REFERENCES: Smith CS, Nork SE, Sangeorzan BJ: The extruded talus: Results of reimplantation. J Bone Joint Surg Am 2006;88:2418-2424. Brewster NT, Maffulli N: Reimplantation of the totally extruded talus. J Orthop Trauma 1997;11:42-45.

DISCUSSION: Stress fractures of the navicular are often seen in running and jumping sports. Whereas most individuals heal with nonsurgical management consisting of 6 weeks of casting, this gymnast has had pain for 1 year and nonsurgical management has failed. Open reduction with bone grafting is the preferred treatment. REFERENCES: Quirk RM: Stress fractures of the navicular. Foot Ankle Int 1998;19:494-496. Saxena A, Fullem B, Hannaford D: Results of treatment of 22 navicular stress fractures and a new proposed radiographic classification system. J Foot Ankle Surg 2000;39:96-103.

Because the patient has significant arthritis, arthrodesis is the treatment of choice. Adding a bone graft will prevent further shortening and add length to her toe, resulting in improved cosmesis.

The history and MRI findings indicate the presence of anterior tibiotalar osteophytes. The most specific finding on physical examination is pain with forced dorsiflexion.

DISCUSSION: The fracture at the insertion of the AITFL into the fibula represents a syndesmosis injury. In some cases, a direct repair of the fracture will stabilize the syndesmosis, but in most cases this injury should most likely be reinforced by placing a screw or suture tensioning device across the syndesmosis for additional support. A Brostrom or allograft reconstruction is indicated for an ankle sprain involving the ATFL or CFL. Simply excising the fragment will leave the patient with an incompetent syndesmosis. Repairing the SPR with or without a groove deepening procedure is indicated if there is evidence of subluxated or dislocated peroneal tendons, which is not demonstrated on the CT scans. The bone has been avulsed off the fibula by the portion of the AITFL that attaches to the fibula, therefore indicating that there is a syndesmosis injury. Allograft lateral ligament reconstruction and excision of loose body/fracture fragment are incorrect procedures based on location. The deltoid is a medial structure and this fracture is lateral. The ATFL and CFL attach at the inferior margin of the fibula near the lateral process of the talus and calcaneus. A SPR avulsion would present as an avulsion off the lateral wall of the fibula, not superior and not into the syndesmotic space as shown on the CT scans.

The most common mechanism of injury for turf toe is a hyperextension injury to the MTP joint. The foot is typically in a dorsiflexed position with the heel raised when an external force drives the MTP joint into further dorsiflexion. The joint capsule usually tears at the metatarsal neck because its attachment is weaker there than at the proximal phalanx. Some compression injuries to the dorsal articular surface of the metatarsal head can result from extension or hyperextension.

Dynamic midfoot supination that is the result of peroneal weakness is a common residual problem after cast correction or surgical reconstruction of a congenital idiopathic clubfoot. Dynamic supination is unlikely to resolve spontaneously. Most parents do not want to use brace support forever. Transfer of the posterior tibialis to the dorsum of the foot has shown poor results in clubfeet. Preferred treatments include: 1) transfer of the entire anterior tibialis tendon to the lateral cuneiform, or 2) split transfer of the anterior tibialis tendon to the cuboid or to the peroneus brevis tendon.

Freiberg’s infraction is believed to be an osteochondrosis of the second metatarsal head. It is the only osteochondrosis that has a predilection for females. The typical patient is an athletically active adolescent female. The radiograph shows stage II disease wherein reossification is occurring; it is at this time that the second metatarsal head is most susceptible to deformation. Therefore, initial management should consist of a short leg walking cast.

Compartment syndrome of the anterior and deep posterior compartments results in anterior tibialis and posterior tibialis tendon weakness, respectively. Furthermore, the long flexors to the hallux and lesser toes will be weak as well. The intact peroneus longus overpowers the weak anterior tibialis tendon, resulting in plantar flexion of the first metatarsal, cavus, and hindfoot varus. Therefore, transferring the peroneus longus to the dorsolateral midfoot reduces the first metatarsal plantar flexion torque, and possibly augments ankle dorsiflexion torque.(SBQ12FA.1) Figure A is a radiograph of a healthy, independent 51-year-old male. He is treated with immediate open reduction internal fixation to prevent which of the following complications?Fracture non-unionAvascular necrosisSkin necrosisPlantar flexion weaknessAnkle stiffnessFigure A shows an avulsion fracture of the calcaneal tuberosity. Immediate open reduction and internal fixation is required to prevent wound complications.Displaced avulsion fractures of the calcaneal tuberosity should be managed urgently to prevent necrosis of the soft tissues overlying the heel. In these injuries, the Achilles tendon is securely attached to the fractured tuberosity. Urgent closed reduction and casting is usually not possible due to the power and proximal pull of the triceps surae. Surgical fixation is required. The best treatment modality is open reduction and bone-to-bone fixation with screws. Closed reduction and percutaneous pinning fixation is not strong enough to provide a stable fixation of the tuberosity.Lui reported on avulsion fractures of the bony insertion of the Achilles tendon at the calcaneus. He stated that screw fixation alone is not sufficient for repair of these injuries. His technique involved two suture anchors used capture the small bone fragment to the calcaneus. This allowed for the pull of the triceps surae to be neutralized and early physical therapy.Hess et al. looked at a case series of calcaneal tuberosity avulsion fractures that weretreated in a delayed fashion. All three patients with posterior tuberosity calcaneal avulsion fractures developed skin necrosis because of a delay in treatment.Figure A shows a displaced posterior tuberosity calcaneal avulsion fracture. Illustration A shows skin breakdown overlying the posterior tuberosity calcaneal avulsion fracture.Incorrect Answers:

DISCUSSION: It is often tempting to assign a diagnosis of plantar fasciitis in patients with hindfoot pain. In this patient, the radiographs confirm a diagnosis of a calcaneal insufficiency fracture. The dense condensation of bone on the lateral view confirms the diagnosis. There is no radiographic evidence of a heel spur, osteochondral lesions, or chondrocalcinosis. REFERENCES: Resnick D: Diagnosis of Bone and Joint Disorders, ed 3. Philadelphia, PA, WB Saunders, 1995, p 2591. Kearon C: Natural history of venous thromboembolism. Semin Vasc Med 2001;1:27-37. Aldridge T: Diagnosing heel pain in adults. Am Fam Physician 2004;70;332-338.

Training increases turnover of type I collagen, promoting both synthesis and degradation of collagen and a net increase synthesis of type I collagen in tendon-related tissue. Strenuous endurance training has resulted in decreased collagen cross-links, suggesting increased collagen turnover, but decreased collagen maturation. In human studies, physical training results in increased turnover of collagen. Synthesis and degradation are elevated initially when beginning an exercise program, but degradation products decrease overall. It is not known if activity levels in humans affect the diameter of collagen fibrils or the cross-sectional area of tendons.

DISCUSSION: This patient has end-stage ankle arthritis. A short course of NSAIDs may provide pain and inflammation relief. Bracing with either an ankle-foot orthosis or Arizona brace can reduce pain by offloading the ankle joint. Ankle fusion is a reliable procedure for treatment of end-stage ankle arthritis and is especially recommended for active people after it is determined that nonsurgical measures no longer provide adequate relief. Arthroscopic debridement and cheilectomy may be indicated for bony impingement and mild arthritis with little articular cartilage loss. The long-term results of ankle distraction arthroplasty are not yet well defined but likewise would be reserved for scenarios in which nonsurgical measures no longer provide adequate relief. The patient must be able to wear a thin-wire external fixator for 3 months. RECOMMENDED READINGS: Abidi NA, Neufeld SK, Brage ME, Reese KA, Sabharwal S, Paley D. Ankle arthritis. In: Pinzur MS, ed. Orthopaedic Knowledge Update: Foot and Ankle 4. Rosemont, IL: American Academy of Orthopaedic Surgeons; 2008:159-193. Saltzman CL: Ankle arthritis, in Coughlin MJ, Mann RA, Saltzman CL (eds): Surgery of the Foot and Ankle. Philadelphia, PA, Mosby Elsevier, 2007, vol 1, pp 929-932.

DISCUSSION: The Coleman block test is used to determine the flexibility of the hindfoot. When a block is placed under the lateral border of the foot, the medial column is unsupported. As a result, the first metatarsal drops off the side of the block. If the subtalar joint is flexible, there is no fixed varus deformity of the hindfoot. The hindfoot will no longer be in varus from behind. The varus deformity of the hindfoot will be corrected. If there is no subtalar motion, the varus deformity remains fixed.

DISCUSSION: The stretched peroneus brevis muscle and tendon follow anterior to the fibula and are most likely incarcerated with reduction. The anterior talofibular ligament is too small to prevent reduction of the ankle joint itself. The extensor digitorum brevis originates from the talus; therefore, it is not involved in the tibiotalar joint. The posterior tibial tendon lies medially and would not be interposed into the ankle joint. Similarly, the anterior tibialis tendon also would not be involved. REFERENCES: Pehlivan O, Akmaz I, Solakoglu C, et al: Medial peritalar dislocation. Arch Orthop Trauma Surg 2002;122:541-543. Rivera F, Bertone C, De Martino M, et al: Pure dislocation of the ankle: Three case reports and literature review. Clin Orthop 2001;382:179-184.

The patient most likely has a form of Charcot-Marie-Tooth disease, or hereditary motor sensory neuropathy (HMSN). The most common varieties can now be diagnosed by DNA testing. Mutations have been detected in the peripheral myelin protein-22 (PMP-22) gene in HMSN type IA and in the connexin gene in the X-linked HMSN. Specific DNA diagnosis is useful in genetic counseling. Routine chromosomal testing most likely would not detect these mutations. Nerve conduction velocity study results are normal in some types of HMSN, and delayed nerve conduction, when found, indicates a peripheral neuropathy but does not specify the type or inheritance pattern. Biopsy of the sural nerve or of the quadriceps can be informative in some patients, but is not as specific as DNA testing.

Compartment syndrome of the anterior and deep posterior compartments results in anterior tibialis and posterior tibialis tendon weakness, respectively. Furthermore, the long flexors to the hallux and lesser toes will be weak as well. The intact peroneus longus overpowers the weak anterior tibialis tendon, resulting in plantar flexion of the first metatarsal, cavus, and hindfoot varus. Therefore, transferring the peroneus longus to the dorsolateral midfoot reduces the first metatarsal plantar flexion torque, and possibly augments ankle dorsiflexion torque.