Talocalcaneal coalition in patients who have fibular hemimelia or proximal femoral focal deficiency. A comparison of the radiographic and pathological findings.

The prevalence of congenital anomalies of the foot was studied in ninety-nine children (105 limbs) who had fibular hemimelia or proximal femoral focal deficiency, or both. Twenty-six of these patients had had a Syme amputation at our institution and the specimens were analyzed anatomically; they were found to include fourteen talocalcaneal coalitions (54 per cent). The preoperative radiographs of these same patients, however, revealed only four such coalitions (15 per cent). Thirty-seven of the ninety-nine patients had had a Syme amputation previously at another facility (with subsequent follow-up at our institution), and ten of them (ten feet) had radiographs that were adequate for analysis of congenital anomalies. Forty-two feet that had not yet been amputated were also analyzed radiographically. Nine of these fifty-two feet included in the radiographic analysis had a talocalcaneal coalition, a radiographic prevalence similar to that found on the preoperative radiographs of the twenty-six patients included in the anatomical analysis. The true prevalence of talocalcaneal coalition remains to be determined; however, this can be done only at the time of skeletal maturity. Examination of the twenty-six amputation specimens revealed only one talocalcaneal coalition in the nine patients who had proximal femoral focal deficiency alone, six such coalitions in the eight patients who had only fibular hemimelia, and seven coalitions in the nine patients who had both proximal femoral focal deficiency and fibular hemimelia. These findings should be useful in the evaluation of the radiographic anatomy of the feet in children who have proximal femoral focal deficiency or fibular hemimelia, or both, particularly if limb-lengthening is considered as a treatment option.