66. OSTEOTOMY FOR FEMORAL OR TIBIAL SHAFT MALUNION IN PATIENTS WITH END-STAGE OSTEOARTHRITIS OF THE KNEE

Abstract

Purpose: Femoral and tibial shaft malunion may predispose to knee osteoarthritis but may also pose a problem for knee reconstruction; malposition of total knee prostheses being a known cause of early failure. Limb realignment may prove to be beneficial prior to proceeding with arthroplasty. The purpose of this study was to evaluate the outcome and effect of shaft osteotomy prior to total knee arthroplasty (TKA).

Method: A search of the trauma database between 1987 and 2006 was conducted. Twenty-two osteotomies were performed on 21 patients with femoral or tibial shaft malunion who had been considered for TKA. Mean age at osteotomy was 54 years and mean follow-up 86 months. Time intervals between surgical procedures and Knee Society scores were calculated. Patients were surveyed regarding pain relief and functional improvement.

Results: Femoral osteotomy improved mean Knee Society knee scores from 47 to 76 and function scores from 34 to 61. Tibial osteotomy improved knee scores from 53 to 82 and function scores from 28 to 50. Four osteotomies were complicated by nonunion and required further intervention. Osteotomy subjectively improved pain and function for a mean of 56 months. Femoral and tibial shaft osteotomy delayed TKA in 45% (10 cases) for a mean period of just over 6.5 years (89 and 73 months for femoral and tibial osteotomy respectively). Pre and post Knee society scores were: Femur: knee 56 to 88, function 41 to 72; Tibia: knee 65 to 85, function 25 to 57. One TKA was revised after 11 months due to valgus malalignment and was complicated by a wound infection. There were no other infections or wound complications. The procedure additionally relieved pain and improved function in the remaining 12 joints, not yet requiring arthroplasty.

Conclusion: Femoral and tibial shaft osteotomy may delay and possibly avoid TKA, relieve pain and improve function in patients who present with malunion and end-stage knee arthritis. The complication rate and clinical results of TKA following shaft osteotomy appear to be similar to primary TKA. This treatment strategy should be considered in younger patients with post traumatic osteoarthritis where significant femoral or tibial deformity is present.