Long-term Outcomes Following Syme's Amputation.

BACKGROUND:
The metabolic cost of walking after Syme's ankle disarticulation amputation is minimally more than that for nonamputation. The ability to end weightbearing makes prosthetic fitting relatively simple, and very few patients require extensive rehabilitation or placement in a skilled nursing or rehabilitation facility. In spite of these potential benefits, there is a paucity of objective information on the actual long-term outcomes.

METHODS:
Fifty-one patients were identified who underwent single-stage Syme's ankle disarticulation amputation with excision of the lateral and medial malleoli by a single surgeon during a 23-year period. None of these patients had sufficient tissue to allow amputation at the transmetatarsal or tarsometatarsal levels. Thirty-three underwent amputation due to a diabetic forefoot infection, 11 secondary to a crush injury, 3 for a nondiabetic infection, 3 for a noncorrectable acquired deformity, and 1 for neoplasm. The average age at surgery for the diabetic patients was 62.1 years (range, 36-81 years), with an average follow-up of 6.8 years (range, 4.0-11.6 years). The nondiabetic patients had an average age of 37.8 years (range, 21-65 years), with an average follow-up of 9.3 years (range, 2.2-25.0 years). Patients who were alive and could be contacted were invited to complete the Short Musculoskeletal Function Assessment (SMFA) questionnaire that was scored for functional, mobility, and bothersome indices.

RESULTS:
Seventeen of the 33 diabetic patients died. Four (12.1%) were converted to transtibial amputation. One of the nondiabetic patients died, and 1 (5.5%) was converted to transtibial amputation. Eleven of the 33 patients who were contacted completed the SMFA. All of these patients demonstrated favorable outcome scores in the mobility, functional, and bothersome indices (average mobility index of 17.2, functional index of 14.7, and bothersome index of 16.7 for nondiabetic patients compared to 34.7, 29.9, and 30.6 for diabetic patients, respectively).

CONCLUSION:
The objective information derived from this investigation supports the opinion that patients who underwent Syme's ankle disarticulation amputation appear to fare better than similar patients with transtibial amputation. These data also refute the notion of high complication rates and difficulties with prosthetic fitting. These patients required less rehabilitation and achieved improved levels of functional independence as demonstrated by favorable functional, mobility, and bothersome indices.

LEVEL OF EVIDENCE:
Therapeutic Level IV, retrospective series.