Primary total knee arthroplasty in severe valgus knee

Outcome of primary total arthroplasty for osteoarthritis of the knee with valgus deformity.

Between 2005 and 2007, 28 primary total knee replacements were performed for osteoarthritis of the knee with valgus deformity. 21 cases were women and 7 men with a mean age of 66.6 years (extremes 54-81). The clinical and radiological evaluations were done considering the knee range of motion, Knee Society Score (KSS) and femorotibial angle measured on the frontal standing long leg X-rays. Preoperatively, the knee valgus deformity angle was 6 to 15 degrees in 14 cases, 15 to 25 degrees in 10 cases and over 25 degrees in 4 cases.

After a mean follow-up time of 14 months (extremes 7-29), the knee range of motion improved from a mean of 71 degrees (extremes 52-87) preoperatively to a mean of 95 degrees (extremes 78-110) postoperatively. The KSS value improved from 21.3 points (extremes 1-33) preoperatively to 80.7 points (extremes 70-92) postoperatively and the frontal femorotibial angle from a mean value of 21 degrees (extremes 11-39) of valgus before surgery, to a mean of 9 degrees (extremes 0-12) of valgus after surgery.

Long leg AP view X-ray examination in standing position is mandatory. The standard medial parapatellar approach is appropriate in this type of arthroplasty even if significant knee valgus deviations are present because it avoids the lateral approach complications. Postoperatively, one can get an aligned and stable knee if a judicious and progressive periarticular soft tissues balancing is achieved, in both flexion and extension position.