Review Question - QID 3823

Distraction bone block arthrodesis in isolation would be unlikely to improve pain related to peroneal impingement. Lateral wall exostectomy would likely be needed for this, and should be concomitantly performed in most cases.

Calcaneal fracture malunions demonstrate several common patterns. Patients may manifest pain from anterior tibiotalar impingement (a result of a low talar declination angle), difficulty with shoe wear due to shortening and widening of the hindfoot, painful talonavicular subluxation, subfibular impingement, and post-traumatic subtalar osteoarthritis. The distraction bone block arthrodesis procedure was developed to eliminate the pain of subtalar arthritis while simultaneously normalizing hindfoot height by inserting a contoured structural bone graft into the subtalar joint. The procedure can correct pathologic hindfoot varus/valgus and restore a normal talocalcaneal angle, thereby improving symptomatic post-traumatic pes planus. The procedure alone does not address lateral wall blowout causing subfibular or peroneal impingement, which requires lateral wall exostectomy. Lateral wall exostectomy therefore should be done in addition to address this issue.

Carr et al. first reported the use of subtalar distraction bone block arthrodesis for salvage of post-traumatic subtalar arthritis following calcaneus fractures. In their 16 patient series, distraction of the subtalar joint with insertion of the bone block allowed for correction of talocalcaneal angle, restoration of hindfoot height, and improvement in symptoms related to tibiotalar impingement.

Clare et al. evaluated a treatment protocol for calcaneal malunions based upon the classification of Stephens and Sanders. Type II and III malunions were treated with subtalar bone-block arthrodesis and other concomitant procedures. They found that their treatment protocol was effective for pain relief, re-establishing a plantigrade foot, and improving function. The most difficult component of the case was restoration of calcaneal height.

Braley et al. evaluated isolated lateral decompression in the treatment of symptomatic calcaneal malunions without concomitant subtalar arthrodesis. These 11 patients had persistent lateral sided pain and their malunions did demonstrate subtalar involvement. The authors reported 9 of the 11 patients had a satisfactory outcome with lateral decompression alone. They concluded that a lateral decompression in management of symptomatic malunions with lateral-sided symptoms is an essential consideration.

Incorrect Answers:
Answer 1: Talar declination angle describes the relative plantar- or dorsiflexion of the talus relative to the ground.
Answer 2: Hindfoot alignment can be improved with distraction arthrodesis.
Answer 3: Arthrodesis addresses painful subtalar arthritis.
Answer 4: Restoration of the normal talocalcaneal angle can be achieved, which can also normalize the talonavicular relationship.