Short-Term Clinical Outcomes of High Tibial Osteotomy with the iBalance HTO System

High tibial osteotomy (HTO) is an invaluable tool in the treatment of a variety of conditions in active patients with varus malalignment of the knee. The polyetheretherketone (PEEK) iBalance HTO system has been designed to make the osteotomy safer, more reproducible, and avoid metal hardware related complications. The purpose of this study was to evaluate short-term outcomes in patients who underwent an open wedge high tibial osteotomy with the iBalance HTO system.

We identified patientswho underwent HTO using iBalance with a minimum of 2-year follow-up. Medical records were reviewed for demographics, Workers Compensation and no-fault insurance claims, history of smoking, concomitant procedures, degree of correction, and complications. Patient outcomes using Knee injury and Osteoarthritis Outcome Score (KOOS) and visual analog scale (VAS) were recorded before undergoing HTO and compared with those recorded after a 2-year follow-up. Statistical analysis was performed using paired sample t-tests with p < 0.05 considered significant.

Twenty-three patients with mean age of 44.9 (± 8.48) were identified. The mean correction angle was 9.9° (range: 5° to 15°). Sixteen patients underwent a concomitant procedure. The average follow-up was 2 years (range: 2 to 3.5 years). Six patients reported a positive history of smoking. The mean preoperative KOOS scores of symptoms, pain, activities of daily living (ADL), sport, and quality of life were 14 (± 18.5), 53.1 (± 14.8), 69.1 (± 21.7), 29.2 (± 22.0), and 30.0 (± 20.0), respectively. The mean preoperative VAS score was 5.5 (± 2.5). At follow-up, the mean scores of symptoms, pain, ADL, sport, and quality of life all improved to 67.53 (± 24.9), 68.06 (± 23.4), 75.74 (± 25.3), 45.91 (± 36.1), and 43.47 (± 33.4), respectively. The mean VAS at follow-up was 1.9 (± 2.1). There was a significant increase (p < 0.05) in all KOOS categories, except ADL. Additionally, there was a statistical difference between smoking and change in ADL score. Former smokers demonstrated an average decrease of 10.3 points, increasing their disability, and nonsmokers increased 15.3 points on the KOOS ADL scale, decreasing their disability. There were three complications (DVT, cellulitis, and serosanguinous drainage) within a month after the procedure. There were three complications, including a revision HTO, pes anserine bursitis, and lateral hamstring tendinitis, within the 2-year follow up including one revision after 1 year. Five patients went on to total knee arthroplasty at an average of 3 years (range: 1 to 5 years).

This study suggests that the iBalance medial opening wedge HTO system implant can be used with comparable outcomes to traditional methods, however the conversion rate to total knee arthroplasty may be higher than previously reported. This appears to be unrelated to implant choice and likely related to extended indications for the procedure in younger patients refusing knee arthroplasty. The iBalance medial opening wedge HTO system has shown to be safe, removing many of the complications existing with other osteotomy implant options. Our findings highlight the importance of additional studies in order to investigate the risk factors causing progression from HTO to TKA.