Subtubercle Osteotomy for Medial Compartment Osteoarthritis of the Knee Using Ilizarov Technique: Survival Analysis and Clinical Outcomes.

BACKGROUND: High tibial osteotomy with acute correction and internal fixation can be used to correct malalignment and malorientation and reduce symptoms in patients with medial compartment osteoarthritis of the knee. To address the inadequacies of this technique, we performed a series of subtubercle tibial osteotomy (STO) procedures using circular ring fixation to correct knee varus malalignment and joint malorientation. The purpose of this study was to analyze the ability of this technique to delay subsequent knee arthroplasty and decrease symptoms.

METHODS: Sixty-one patients had a total of 72 STO procedures using the Ilizarov technique to correct a varus deformity of the proximal part of the tibia. Radiographic measurements were performed at the time of presentation and after osseous union and frame removal. Clinical and radiographic variables were compared from presentation to the time of the latest follow-up. We performed a survival analysis, and our primary outcome was the time to conversion to knee arthroplasty.

RESULTS: Radiographic measurements, including mechanical axis deviation, medial proximal tibial angle, and joint line congruence angle, significantly improved after deformity correction (p < 0.001 for all). In patients with a preoperative flexion contracture, the proximal posterior tibial angle significantly increased toward normal values (mean, 77.8° pretreatment versus 82.4° posttreatment; p = 0.007). Survival analysis demonstrated a rate of native knee-joint survival without conversion to arthroplasty of 94.2% (95% confidence interval [CI], 83% to 98%) at 5 years, 84.0% (95% CI, 69% to 92%) at 10 years, and 51.3% (95% CI, 28% to 71%) at 15 years. In addition, time-trade-off and Brief Pain Inventory outcomes significantly improved (p < 0.001). The complication rate was 8%.

CONCLUSIONS: STO procedures using the Ilizarov technique for symptomatic varus knee deformity, performed over the course of 18 years, resulted in high knee survival rates without arthroplasty and significant improvement in clinical status. The STO technique provides several advantages over acute correction with internal fixation through a conventional high tibial osteotomy, including maintenance of the patellofemoral relationship, no retained implants, and accurate coronal and sagittal plane corrections.

LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.