Functional Ability After Above-the-knee Amputation for Infected Total Knee Arthroplasty

Background Prosthetic joint infection is an uncommon but serious complication of total knee arthroplasty (TKA). Control of infection after TKA is not always possible, and the resolution of infection may require an above-knee amputation (AKA).

Questions/purposes The purpose of this study was to determine the etiology of AKA and the functional outcomes of AKA after infected TKA.

Methods We retrospectively reviewed 35 patients who underwent AKA after an infected TKA. The amputations were performed an average of 6 years (range, 21 days to 24 years) after primary TKA. There were 19 females and 16 males with a mean age of 62 years (range, 26-88 years). Patient demographic information, comorbidities, surgical treatments, cultures, and culture sensitivities were recorded. Complications and functional status, including SF-12 and activities of daily living questionnaires, after AKA were also studied. The minimum followup was 7 months (mean, 39 months; range, 7-96 months).

Results Two patients died secondary to cardiac arrest and 13 more died during the followup period of unrelated causes. Nine patients required irrigation and débridement for nonhealing wounds after AKA and two patients had repeat AKA for bony overgrowth. Of the 14 patients fitted for prostheses, eight were functionally independent outside of the home. Patients fitted with a prosthesis had higher mean activities of daily living scores (58 versus 38) and also tended to be younger with fewer comorbidities than those who were not fitted with a prosthesis.

Conclusions We found low functional status in living patients with an AKA after infection with only half of the patients walking after AKA.

Level of Evidence Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.