Extended medial gastrocnemius rotational flap for treatment of chronic knee extensor mechanism deficiency in patients with and without total knee arthroplasty.

Nine patients with chronic extensor mechanism disruption were treated with an extended medial gastrocnemius rotational flap reconstruction of the extensor mechanism. Seven patients previously had total knee arthroplasty and two patients had chronic infection of nonreplaced, native knees. Four patients previously had failed Achilles' tendon allograft reconstruction after total knee arthroplasty and two were complicated by infection. Infected arthroplasty patients had a staged procedure with placement of an antibiotic spacer after debridement and extended medial gastrocnemius rotational flap, followed by total knee arthroplasty replant 8 weeks later. The four infected arthroplasty patients had medical comorbidities that included a patient with HIV and hemophilia, and two with diabetes mellitus. Another patient with rheumatoid arthritis was severely malnourished as a result of dumping syndrome. Of the four patients treated by this two-stage procedure, one died in the early postoperative period from chronic medical issues after the second stage and another patient elected to have above-knee amputation after the first stage because of severe reflex sympathetic dystrophy. The final group of seven patients was studied at a mean followup of 21 months (range, 7-31 months), the average extensor lag was 13.5 degrees (range, 0-50 degrees ), and the average range of motion was 2 degrees to 93 degrees . The two patients with nonreplaced, native knees had extensor lags of 30 degrees and 10 degrees . All patients were able to regain sufficient extensor mechanism strength to return to independent ambulation, and all infections resolved after treatment. Two patients were able to ascend stairs foot over foot without support. In addition to the patient who had amputation, the other complication involved a wound breakdown that required a free flap at 13 months in a patient who had a failed Achilles' tendon allograft reconstruction after takedown of a knee fusion. Medial gastrocnemius flap reconstruction can provide successful salvage of a failed extensor mechanism allograft or an alternative to allograft reconstruction in patients with poor soft tissue coverage, previous infection, or a compromised immune system.