Improved Coronal Alignment Using the Preemptive Joint Line Convergence Angle Compensation Method in Medial Open Wedge...

Accurate coronal alignment is crucial in medial open wedge high tibial osteotomy (MOWHTO). Postoperative changes in the joint line convergence angle (JLCA) can cause coronal alignment errors. A preemptive JLCA compensation method has been proposed to address this; however, its clinical value remains unclear.

To assess the accuracy of the preemptive JLCA compensation method for correction angle calculation in MOWHTO.

Cohort study; Level of evidence, 3.

Patients who underwent MOWHTO for varus osteoarthritis alignment between 2010 and 2024 were reviewed. The patients were classified into 2 groups based on whether the preemptive JLCA compensation method was applied (group 1: the conventional Miniaci method, group 2: the preemptive JLCA compensation method). After propensity score matching for sex, body mass index, hip-knee-ankle (HKA) angle, Kellgren-Lawrence grade, and correction angle on standing radiography, we conducted a comparative analysis of radiologic outcomes (weightbearing ratio) and functional outcomes (Lysholm score and International Knee Documentation Committee [IKDC] scores). Acceptable alignment was defined as a postoperative weightbearing line ratio between 55% and 70%.

After propensity score matching, 20 patients were included in each group. The mean preoperative HKA angle was varus 6.2°± 2.2° and 6.3°± 2.2° (P = .922), while the correction angle measured by the Miniaci method was 10.0°± 2.1° and 10.3°± 1.7° for the conventional and preemptive JLCA compensation method group, respectively (P = .855). The mean postoperative weightbearing line ratio at 1 year postoperatively was 64.1 ± 7.4 and 62.5 ± 4.7 for the conventional and preemptive JLCA compensation methods, respectively, with no significant difference. However, 95.0% of patients in the JCLA modification group achieved acceptable target alignment, compared with 60.0% (12/20) in the conventional group (P = .014). Despite the significant difference in coronal alignment accuracy, functional outcomes showed no significant difference between the 2 groups.

The preemptive JLCA compensation method significantly improved correction accuracy, with 95.0% of patients achieving acceptable target alignment, compared with 60.0% with the conventional Miniaci method, although no significant differences in clinical scores were found in the short-term follow-up period.