8. Foot and Ankle MCQs

The hallmark of the juvenile bunion is metatarsus primus varus. Increased flexibility of the first metatarsal phalangeal joint leads to increased deformity. The hallux valgusangle is less than the adult bunion. Bursal thickenings and prominence of the medial eminence are less in a juvenile bunion.

DISCUSSION: Sever disease is a traction apophysitis at the Achilles tendon insertion on the calcaneus. Plain radiographs may be unremarkable for this condition. Other osteochondroses of the foot include Kohler disease (tarsal navicular), Freiberg infraction (lesser metatarsal head), and Thiemann disease (great toe phalanx).

DISCUSSION: The most common inherited neuromuscular disease seen by orthopaedic surgeons is CMT, which is an inherited autosomal-dominant disease. It is more commonly seen in men due to the nature of the inheritance. Identification of cavus deformity in the foot of a child should arouse suspicion.

DISCUSSION: The patient has a medial subtalar dislocation. These injuries should be reduced as soon as possible to minimize risk to the skin. Most often, this can be done easily, and further radiographic evaluation then can be performed as necessary. On rare occasions, closed reduction is not possible because of fractures of the articular surface of the talus, navicular, interposed extensor digitorum brevis, or transverse fibers of the cruciate crural ligament. The posterior tibial tendon is the most common obstruction to closed reduction in lateral subtalar dislocations, which are less common than medial dislocations. The majority of both injuries can be managed by closed reduction and immobilization. REFERENCES: Mulroy RD: The tibialis posterior tendon as an obstacle to reduction of a lateral anterior subtalar dislocation. J Bone Joint Surg Am 1953;37:859-863. Heckman JD: Fractures and dislocations of the foot, in Rockwood CA, Green DP, Bucholz RW (eds): Fractures in Adults. Philadelphia, PA, JB Lippincott, 1991, pp 2093-2100. Saltzman C, Marsh JL: Hindfoot dislocations: When are they not benign? J Am Acad Orthop Surg 1997;5:192-198.

DISCUSSION: General principles can be used as bunion surgery guidelines even though there is extensive debate on the topic. A distal metatarsal osteotomy is most appropriate for patients with mild deformity and no transfer metatarsalgia. A proximal osteotomy potentially can correct more severe deformities. A Lapidus procedure, or tarsometatarsal fusion, provides the highest potential to correct deformity plus the advantage of stabilizing the first tarsometatarsal joint and limiting or eliminating transfer metatarsalgia. A first MTP fusion is most appropriate for patients with severe first MTP arthrosis.

Whereas it is difficult to distinguish between cellulitis, septic joint, osteomyelitis, and early Eichenholtz stage 1 Charcot, the presence of a fracture in the absence of ulcerations with a normal WBC count and serum glucose strongly indicates that the described symptoms are due to an early Charcot process alone. A technetium Tc 99m scan alone would not be helpful; however, the addition of a sulfur colloid marrow scan or indium In 111 scan may be more specific to rule out infection, though it is not warranted here. Total contact casting with non-weight-bearing or limited weight bearing during Eichenholtz stage 1 when the foot is warm, erythematous, and swollen is advised to help prevent deformity. Alternatively, stabilization with pneumatic bracing may also be considered. While some authors have proposed early fixation or arthrodesis for Eichenholtz stage 1, the gold standard is still total contact casting with no to limited weight bearing until the swelling resolves and evidence of consolidation is seen on radiographs.

While Köhler’s disease has a benign course, temporary cast immobilization has been shown to result in a shortened duration of symptoms. Core decompression or other surgery is not warranted because of the benign nature. Shoe inserts may be beneficial, but there are no studies to support their use.

Painful incisional neuromas after bunion surgery frequently involve the dorsomedial cutaneous branch of the superficial peroneal nerve. This is the medial branch of the superficial peroneal nerve that terminates as the dorsomedial cutaneous nerve to the hallux. Branches of the deep peroneal nerve to this area are rare, and no branches to this area exist from the sural nerve. The saphenous nerve branches are generally more proximal, and the medial plantar nerve lies plantarly.

Lesser-toe plantar plate injuries are becoming increasingly recognized. Patients typically have an increase in pain, a positive Lachman test result upon examination, and deviation of the MTP joint. On radiograph, MTP subluxation can be appreciated. Nonsurgical treatment with a metatarsal pad may be attempted. Many patients who have surgery will have a partial or full tear of the plantar plate. The repair necessitates reinsertion of the plantar plate to the base of the proximal phalanx.

In a patient with inflammatory arthritis, advanced hallux valgus deformity in conjunction with lesser metatarsophalangeal joint destruction and subluxation warrants fusion of the first metatarsophalangeal joint and lesser metatarsal head resections. Hallux valgus correction will fail because of incompetent soft tissues. A Keller resection arthroplasty is not indicated in this age group. Synovectomy is contraindicated because of evidence of erosive changes of the lesser metatarsophalangeal joints.

Upon review of the radiograph give, there is no evidence of fracture or osteonecrosis. Upon review of the article above the most likely diagnosis is “Turf-Toe” or the disruption of the plantar plate. The patient has mechanism of injury, hyperextension and sequelae, decreased push-off strength, which is consistent with this diagnosis. Rupture of the FHL would most likely result in inability to continue playing while hallux rigidus is a potential chronic sequelae with associated dorsal osteophyte formation.

The dislocation is between the medial and middle cuneiform. Although the first and second tarsometatarsal joints are aligned, there is a gap between the cuneiforms. The radiograph shows a Lisfranc dislocation variant. In a healthy active individual, open reduction and internal fixation yields the best results. The reestablishment of the normal arch and medial column support with anatomic reduction is critical to obtaining the best possible outcome from these injuries.

This injury pattern is one of a direct trauma to the mid aspect of the foot. Without additional forces involved, capsular ligamentous injury is not anticipated; therefore, the injury should be a stable pattern. Treatment should consist of protected weight bearing as tolerated in a walking boot or walking cast. Surgical intervention is not indicated with this pattern of injury. With injuries to the midfoot area where the exact mechanism of injury is uncertain, there should be a high index of suspicion for an associated injury to the tarsometatarsal joint, and standing radiographs or stress radiographs should be obtained.

Tillaux and triplane fractures occur in adolescents as the result of an external rotation injury of the ankle. As seen on the CT scan, the growth plate starts to close during adolescence; therefore, growth arrest resulting in limb-length discrepancy or angulation is less of a concern in this age group than achieving joint congruity. The joint should be surgically reduced if displacement is greater than 2 mm to minimize the chances of late arthrosis.

DISCUSSION: Because the patient has failed to respond to appropriate nonsurgical management and imaging studies are normal, the use of arthroscopy not only aids in the diagnosis of chronic ankle pain, but is also helpful in its treatment. In patients with this condition, typical findings include synovitis in the lateral gutter and fibrosis along the talofibular articulation; syndesmosis chondromalacia of the talus and ankle also may be found. In patients with anterior soft-tissue impingement, approximately 84% who have a poor response to nonsurgical management will have a good to excellent response after arthroscopic synovectomy and debridement.

DISCUSSION: Excessive hindfoot valgus can lead to abutment between the calcaneus and fibula. This valgus force can lead to a stress fracture of the distal fibula. Surgery may be required if an insufficiency fracture recurs despite orthotic management. Of the choices listed, a subtalar arthrodesis is most likely to achieve rebalancing of the foot at the level of the deformity.

Posterior rhizotomy provides a permanent reduction in tone of spastic muscles. Potential drawbacks of the procedure include excessive muscle weakness, hip dislocation, and spinal deformity. Intramuscular botulinum-A toxin results in permanent blockade of presynaptic release of acetylcholine across the neuromuscular junction. The clinical effect usually resolves after 3 to 6 months due to neural regeneration. Tone-reduction AFOs have not been shown to reduce tone. A baclofen pump could offer prolonged reduction in tone, but not a single intrathecal injection.

Long-term outcomes after an ankle syndesmotic injury are most correlated with an anatomic reduction of the ankle syndesmosis. Formal open reduction of the syndesmosis has been shown to improve outcomes by improving the reduction quality.While the importance of anatomic reduction of a syndesmotic injury is clear, controversy exists regarding the ideal method of fixation. No significant differences are reproducibly reported in regards to number of syndesmotic screws, size, or number of cortices. There is emerging data supporting the use of suture button fixation.Wikeroy et al. reviewed 48 patients at a mean of 8.4 years, and they found that patients with a difference in the syndesmotic width between the operated and the nonoperated ankle of 1.5 mm or more showed inferior results. Posterior malleolar fragments and obese patients also had worse outcomes.Schepers et al. published a review on the suture button device comparisons to traditional screw fixation, reviewing 6 biomechanical studies and 34 clinical studies. They found that the suture button systems have similar outcomes to screw fixation, but insufficient long-term and high-quality evidence prevented a strong conclusion. Implant removal in the suture button groups averaged 10%, while screw removal averaged 52%.Sagi et al. reviewed 107 patients with ankle fractures and associated syndesmoticinjuries requiring surgery. They found that 39% were malreduced, but open reduction of the syndesmotic injury cut the malreduction rate by 2/3. They also reported that at a minimum of 2 years follow-up, patients with malreduced syndesmotic injuries demonstrated worse functional outcome scores.Figure A shows an ankle fracture with obvious syndesmotic injury/widening. Incorrect answers:1-4: These choices are not correlated with excellent outcomes with treatment of asyndesmotic injury.

Dorsiflexion of the great toe will accentuate rigidity of the transverse tarsal articulation. Through the windlass mechanism, dorsiflexion of the great toe tightens the plantar fascia, stabilizing the longitudinal arch and placing the foot in supination. Supination makes the talonavicular and calcaneocuboid joints nonparallel, accentuating the rigidity of the transverse tarsal articulation. The heel also tends to go into varus, resulting in obligatory external tibial rotation.

The radiographs show tarsometatarsal joint subluxation without fragmentation. The clinical history and delay in presentation with the radiographic findings suggest a neuropathic or Charcot arthropathy involving the midfoot area. Intact sensory examination to light touch is not diagnostic for an intact peripheral neurologic system; monofilament testing is a more accurate office baseline examination for the presence of sensory peripheral neuropathy. With an acute traumatic Lisfranc fracture-dislocation, a history of a traumatic event is necessary, and radiographic abnormalities are expected, although nonstanding radiographs still may be misleading. Acquired pes planus due to posterior tibial tendon rupture may have negative nonstanding radiographs. Standing radiographs may reveal pes planus. However, intermetatarsal disruption is not expected as seen in a Lisfranc abnormality. Localized osteomyelitis of the foot without a penetrating injury or cutaneous ulceration is extremely unlikely and does not fit with the clinical picture described. An isolated metatarsal stress fracture would show osseous irregularity without the instability pattern pictured.