MEDIAL GASTROCNEMIUS TRANSPOSITION FLAP FOR THE TREATMENT OF DISRUPTION OF THE EXTENSOR MECHANISM AFTER TOTAL KNEE ARTHROPLASTY

We describe a modified technique for the salvage of a total knee arthr oplasty after disruption of the extensor mechanism, Between January an d December 1992, seven patients had reconstruction of the extensor mec hanism with use of a medial or an extended medial gastrocnemius flap, Six: of the seven patients were followed for a mean of thirty-three mo nths (range, twenty-six to forty-one months) and were evaluated both p reoperatively and postoperatively with regard to the knee and function al scores of The Knee Society as well as the range of motion, extensor lag, walking status, and patellar height, The seventh patient was los t to follow-up six months postoperatively and was excluded from the an alysis of the results, Preoperatively; the knee and functional scores were 16 +/- 12.3 points and 12 +/- 12.1 points (mean and standard devi ation), respectively; the mean range of motion was 70 +/- 44.0 degrees ; and the mean extensor lag was 53 +/- 33.4 degrees, Postoperatively, the mean knee and functional scores improved to 82 +/- 12.4 points and 51 +/- 23.0 points, respectively; the mean range of motion improved t o 100 +/- 21.8 degrees; and the mean extensor lag decreased to 24 +/- 18.8 degrees, After the procedure, all patients who previously had bee n dependent on a walker were able to walk about the community with or without a cane, and those who had been dependent on a wheelchair were able to walk with the assistance of a walker, Patellar height was meas ured according to the method of Insall and Salvati for the four patien ts who had a patella, Preoperatively, the patellar heights were grossl y abnormal; postoperatively, they more closely approached accepted nor mal values for three of the four patients. Reconstruction of a complic ated rupture of the extensor mechanism with use of a medial gastrocnem ius transposition flap after total knee arthroplasty is a reliable opt ion for treatment.