Background: This study was performed to investigate anterior ankle impingement after tendo-Achilles lengthening for long-standing equinus deformity in patients with residual poliomyelitis and to investigate whether the severity of preoperative equinus deformity affected the occurrence of symptomatic anterior impingement.
Methods: Twenty-seven consecutive patients (mean age, 43.8 ± 9.4 years) with residual poliomyelitis who underwent tendo-Achilles lengthening for equinus foot deformity were included. On lateral foot-ankle weight-bearing radiographs, the tibiocalcaneal angle, plantigrade angle, and McDermott grade were measured and the presence of anterior blocking spur was evaluated.
Results: Eleven patients (40.7%) had anterior ankle impingement on radiographic findings preoperatively and 24 patients (88.9%) at latest follow-up. There was a significant difference in McDermott grade between preoperative and latest follow-up (P < .001). There were significant differences in tibiocalcaneal angle and plantigrade angle between the patients with anterior ankle pain and without anterior ankle pain (P = .006 and .011, respectively) and between the patients with anterior blocking spur and without anterior blocking spur (P = .005 and .010, respectively).
Conclusions: Most patients with residual poliomyelitis had anterior ankle impingement after tendo-Achilles lengthening for long-standing equinus deformity, and the presence of symptomatic anterior ankle impingement was significantly associated with the severity of the equinus deformity. Therefore, for residual poliomyelitis patients with severe long-standing equinus deformity, surgeons should consider the possibility of a subsequent anterior procedure for anterior impingement after tendo-Achilles lengthening.
Level of evidence: Level IV, retrospective case series.
Keywords: anterior ankle impingement; long-standing equinus deformity; residual poliomyelitis; tendo-Achilles lengthening.