Conversion to Total Knee Arthroplasty After High Tibial Osteotomy: A Systematic Review and Meta-analysis

High tibial osteotomy (HTO) is a treatment option for younger, active patients with medial compartment knee osteoarthritis. Clinical results of HTO have been shown to deteriorate over time despite initial satisfactory results, requiring patients to eventually undergo conversion to total knee arthroplasty (TKA). Evidence monitoring survivorship of HTO remains scarce and potentially outdated. To investigate the impact of concomitant cartilage repair procedures, conversion to TKA, and associated complications for HTO. Systematic review; Level of evidence, 4. We searched MEDLINE, Embase, Cochrane Library, and SCOPUS from inception to July 18, 2023, for studies reporting on survivorship and associated complications after medial opening-wedge HTO. Pooled analysis of conversion to TKO was categorized as occurring at <5 years, 5 to 10 years, or >10 years postoperatively. Further subgrouping was performed on studies reporting on HTO with concomitant cartilage repair procedures. Overall, 59 studies comprising 5162 patients were included. Rates of conversion to TKA were 4.5% at <5 years, 8.3% at 5 to 10 years, and 11.2% at >10 years. When comparing patients with isolated HTO versus HTO with concomitant cartilage procedures (including mesenchymal stem cell augmentation, osteochondral allograft transplantation, microfracture, abrasion arthroplasty, and autologous chondrocyte implantation), there was no significant difference in survival rates at <5 years (relative risk, 0.78 [95% CI, 0.45-1.33]; P = .36) or 5 to 10 years (relative risk = 0.76 [95% CI, 0.32-1.83]; P = .55). The overall complication rate was 12.1%; intraoperative lateral hinge and tibial plateau fractures had pooled complication rates of 1.6% and 2.0%, respectively. The rate of nonunion was 1.7%, and pooled rates of superficial and deep infections were 2.6% and 2.0% respectively. Rates of conversion to TKA and complications were low and acceptable, although survival rates decreased with time. Concomitant cartilage repair procedures as a whole did not significantly improve survivorship; however, more high-quality studies are warranted to determine the impact of individual concomitant cartilage repair procedures.