Comparison of the indications for high tibial osteotomy and double-level osteotomy for the correction of diverse lower-leg deformities in an Asian population with medial compartment osteoarthritis: a retrospective observational study.

PURPOSE:Double-level osteotomy (DLO) for knee osteoarthritis is becoming increasingly popular to achieve superior anatomical correction. This study aimed to compare the indication for open-wedge high tibial osteotomy (OWHTO) and DLO and to investigate preoperative bone morphology. METHODS:Data of 166 knees treated with osteotomy were evaluated. The weight-bearing line ratio, mechanical lateral distal femoral angle (mLDFA), and mechanical medial proximal tibial angle (mMPTA) were measured. Bone deformity assessment and osteotomy simulation were conducted. Normal values of mLDFA and mMPTA were defined as 85-90°. Bone deformity was classified into four patterns: femoral, tibial, both, and no deformity. Simulation was performed to achieve a postoperative weight-bearing line ratio of 62%. Distal femoral osteotomy (DFO) or OWHTO was performed to achieve an mLDFA of 85° or mMPTA of up to 95°. If the postoperative parameter remained outside the correctable limit, DLO was performed. Cases were classified according to the corrective surgery performed, and those that could not be corrected after DLO were classified into the uncorrectable group. RESULTS:Femoral, tibial, both, and no deformities were observed in 14.2%, 37.8%, 10.7%, and 33.9% of cases, respectively. No cases were classified into the DFO group; however, 53.6%, 38.1%, and 8.3% were classified into the OWHTO, DLO, and uncorrectable groups, respectively. CONCLUSION:Bone deformity differed among cases, and only one-third had tibial deformity. OWHTO and DLO were indicated in approximately 50% and 40% of cases, respectively. Our study results reinforce the importance of evaluating leg morphology before surgical planning to achieve acceptable alignment.