To evaluate the clinical efficacy of applying self-designed modular osteotomy instrumentation in minimally invasive total knee arthroplasty and the outcomes of the early follow-up.

A total of 95 patients with severe osteoarthritis of the knee underwent total knee arthroplasty in the First Affiliated Hospital of Sun Yat-sen University were randomly divided into the minimally invasive and conventional groups. The minimally invasive group were treated with minimally invasive total knee arthroplasty applying self-designed modular osteotomy instrumentation. Preoperative and postoperative Knee Society score (KSS), visual analogue scale (VAS) and Ⅹ-ray image data (axial alignment of lower extremity, femural angle, tibial angle and posterior tibial slope, ) were statistically compared between two groups by subsequent follow-up by student t test.

In total, 87 patients were followed up for over two years, 42 in the minimally invasive group and 45 in the conventional group. In the minimally invasive group, the operation time was considerably longer than that in the conventional group (t=9.275, P<0.05). Intraoperative hemorrhage, transfusion and drainage volumes did not significantly differ between two groups (all P>0.05). No skin necrosis, deep infection or nerve blood vessel injury was observed in two groups. X-ray imaging data, such as axial alignment of lower extremity, femoral angle, tibial angle and posterior tibial slope did not significantly differ between two groups (all P>0.05). During two-week follow-up, parameters including KSS, VAS in the minimally invasive group were significanly higher than those in the conventional group (t=1.518 P<0.05), except KSS clinical score at postoperative two weeks which was not significant different (P>0.05). However, the scores of each parameter did not significantly differ between two groups after three-month follow-up(P>0.05).

Minimally invasive total knee arthroplasty using the self-designed modular osteotomy instrumentation yields higher short-term clinical efficacy and a similar radiological results compared with conventional artificial TKA; the whole clinical efficacy remains to be further investigated by a longer follow-up.