To observe the efficacyof computer-navigation-assisted high tibial osteotomy (HTO) combined with arthroscopy for genu varum.

This retrospective study collected 20 cases, including seven males and 13 females of genu varum with medial compartment osteoarthritis treated in Shanghai Changhai Hospital from November 2018 to January 2019. Inclusive criteria: medial compartment osteoarthritis of knee joint, varus deformity of knee joint and varus deformity of proximal tibia. Exclusion criteria: lateral compartment osteoarthritis of knee joint, lateral meniscus injury or operation history, knee flexion contracture > 10 °, severe obesity. The surgical method was computer-navigation-assisted open-wedge high tibial osteotomy combined with arthroscopic surgery. Mechanical tibial femoral angle (mTFA), proximal tibial medial angle (MPTA), weight-bearing line distribution, joint line convergence angle (JLCA) were measured before and after operation as well as pre-operationgoal. Lysholm score and Hospital for Special Surgery (HSS) score were measured before and after operation. Paired t test and Mann-Whitney test were performed.

The average age of 20 patients was(55±7)years, and the average follow-up time was (11±3)months. MTFA, MPTA, JLCA and weight-bear-line position were significantly improved after operation. Both Lysholm score and HSS score were higher than those before surgery[67(60, 75) vs. 51(46, 61)(Z=-4.22, P<0.001), 67(59, 71)vs. 55(49, 59)(Z=-3.64, P<0.001)]. The differences in postoperative mTFA, correction angle and distraction height were not statistically significant comparing with the preoperative targets (P>0.05). Arthroscopic examination revealed six patients with medial meniscus tear, two patients with medial meniscus posterior foot root tear, three patients with intercondylar fossa osteophyte or ACL degeneration.

The computer-navigation-assisted high tibial osteotomy has satisfactory accuracy and arthroscopic surgery is an indispensable part of high tibial osteotomy.