To investigate the clinical effect of different modular knee prosthesis in treating moderate to severe genu valgum.

Retrospective analysis was conducted on the patients who underwent total knee replacement due to moderate or severe valgus knee deformity from March 2012 to August 2016, excluding the patients with mild valgus knee deformity and significant abnormalities in the anatomical axis of the lower limbs. According to the different surgical and prostheses, they were divided into three groups. Group A: conventional knee prosthesis with extension pole group; group B: condylar constrained knee with extension pole group; group C: supracondylar osteotomy with extension pole group. Joint function and surgical effect of the affected limb were evaluated by measuring femorotibial angle, visual analogue score and knee function score. Paired sample t test was used for intra-group comparison before and after surgery, and repeated measurement data ANOVA was used for inter-group comparison.

All the 43 patients (59 knees) were followed up postoperatively with an average time of (16±3) months. There were 12 male cases with 14 knees and 31 female cases with 45 knees. The average age was (56.5±1.7) years. Among them, there were 19 patients (27 knees) in group A, 13 patients (18 knees) in group B, and 11 patients (14 knees) in group C. No postoperative complications such as infection, joint instability, and prosthesis loosening occurred in all patients. At the last follow-up, the femorotibial angle(t=17.979, 16.398, 13.962), visual analogue score (t=-35.159, -29.469, 25.410) and knee function score (t=22.544, 20.221, 12.841) of the affected limb in each group were significantly improved compared with those before and after operation (P<0.05). There were no statistically significant differences in femorotibial angle, visual analogue score and knee function score among the three groups before and after TKA surgery (P>0. 05).

According to the pathological characteristics and clinical classification of genu valgus deformity, the flexible optimization of the combination of different prostheses can achieve satisfactory results, and at the same time maximize the prosthesis-holding capacity and joint instability, so the supracondylar osteotomy with extension is a good way to treat the deformity of knee joint.