Good functional results following high tibial opening-wedge osteotomy of knees with medial osteoarthritis: A prospective study with a mean of 8.3years of follow-up.

BACKGROUND: To report time dependent functional improvement and predictive risk factors for failure when the load in varus knees with medial osteoarthritis is shifted from the medial to the lateral knee compartment.

METHODS: Forty-nine consecutive patients (52 knees), mean age 47 (31-64) years, underwent a high tibial opening-wedge valgus osteotomy stabilized with a Puddu plate and bone grafting. The patients were evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at three and six months, one, two, five and 10years postoperatively with a mean follow-up time of 8.3years (2.0-10.6).

RESULTS: Mean angular correction was 8.0° (four to 12). The five subscores of KOOS increased significantly during the first year by 40-131% from preoperative values, the good results remaining throughout the 10-year follow-up for those with a surviving osteotomy. The outcome was related to the grade of preoperative osteoarthritis. Seven knees were converted to total knee arthroplasty (TKA) mean 6.2years (two to nine) post-operatively, and had a lower KOOS preoperatively than those of surviving osteotomies. The osteotomy survival rate at five years was 94% and at 10years 83%. Patients with KOOS subscore quality of life (QoL) <44 at the two-year follow-up had a 11.7 times higher risk for later TKA than those with QoL ≥44 (P=0.017).

CONCLUSION: High tibial opening-wedge osteotomy for medial knee osteoarthritis resulted in good functional recovery after one year and favorable mid-term results. It may be a good treatment option for middle-aged patients with varus knees and medial osteoarthritis in order to prevent or postpone TKA.