Comparison of Patellofemoral Degeneration After Three Types of High Tibial Osteotomy: Retrotuberosity Biplane Open-Wedge, Supratuberosity Biplane Open-Wedge, and Closed-Wedge Techniques.

BACKGROUND: Retrotuberosity biplane open-wedge high tibial osteotomy (RTOWHTO) may reduce negative patellofemoral joint outcomes. However, no studies have compared patellofemoral cartilage degeneration between RTOWHTO and supratuberosity biplane open-wedge high tibial osteotomy (STOWHTO) using arthroscopic assessment nor compared patellofemoral cartilage degeneration or radiographic patellofemoral-specific parameters between RTOWHTO and closed-wedge high tibial osteotomy (CWHTO). PURPOSE: To compare the arthroscopically assessed femoral trochlear cartilage degeneration and radiographic patellofemoral-specific parameters after RTOWHTO, STOWHTO, and CWHTO. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 58 RTOWHTOs, 59 STOWHTOs, and 88 CWHTOs were examined using first-look arthroscopy between 2013 and 2022. The demographics did not differ significantly between the groups. Hardware removal and second-look arthroscopy were performed, on average, 29.7, 26.9, and 26.7 months after the RTOWHTOs, STOWHTOs, and CWHTOs, respectively (P = .30). Degeneration of the femoral trochlear cartilage was arthroscopically evaluated using the International Cartilage Regeneration & Joint Preservation Society grading system. Patellar translation and height were evaluated radiographically, and patellar height was assessed using the modified Blackburne-Peel ratio. RESULTS: The prevalence rates of femoral trochlear cartilage degeneration were 17.2% (10/58), 39% (23/59), and 19.3% (17/88) in the RTOWHTO, STOWHTO, and CWHTO groups, respectively (P = .008). The prevalence was significantly higher in STOWHTOs than in both RTOWHTOs and CWHTOs (both P = .01), but not significantly different between RTOWHTOs and CWHTOs (P = .83). The increase in lateral patellar translation was significantly greater in the STOWHTOs (1.1 ± 1.5 mm) than in both the RTOWHTOs (-0.1 ± 2.0 mm) and the CWHTOs (0.5 ± 1.2 mm) (P = .001 and .04, respectively). There was no significant difference between the RTOWHTOs and CWHTOs with respect to the increases in lateral translation (P = .10). The lowering in patellar height was significantly greater after the STOWHTOs (-0.2 ± 0.1) than after both the RTOWHTOs (0.0 ± 0.1) and the CWHTOs (-0.1 ± 0.2) (P < .001 and .002, respectively). The lowering was significantly smaller in the RTOWHTOs than in the CWHTOs (P = .02). CONCLUSION: RTOWHTO may provide favorable patellofemoral joint outcomes, with a lower prevalence of trochlear cartilage degeneration and less lateral patellar translation than STOWHTO, as well as less patellar height lowering than both STOWHTO and CWHTO.