High tibial valgus osteotomy (HTO) is an established treatment for medial-compartment osteoarthritis of the knee. We have combined medial open and lateral closed-wedge HTO (hybrid closed-wedge HTO) to overcome the limitations of traditional closed-wedge HTO. Our new hybrid procedure has the following advantages: (1) the bone block removed is smaller in size; (2) the procedure yields optimal geometric characteristics for bone healing; (3) there is no step-off at the lateral osteotomy site; (4) the lateral cortex of the proximal and distal fragments is attached firmly by the oblique osteotomy; and (5) early full weight-bearing walking is possible. This procedure is effective in treating medial-compartment osteoarthritis accompanied by patellofemoral osteoarthritis. The indications for this procedure include a willingness and ability to comply with the postoperative rehabilitation program; a diagnosis of either medialcompartment osteoarthritis or complicated patellofemoral osteoarthritis; and preferably, an age of 70 years or younger, although this is not a strict constraint. Patients are permitted to stand using both legs on the day after surgery and walk with full weight bearing within 2 weeks of undergoing our novel HTO procedure. We describe the details of this surgical technique and the postoperative rehabilitation program for the patients who undergo this treatment.H igh tibial valgus osteotomy (HTO) is an established surgical procedure to correct varus malalignment in patients with medial-compartment osteoarthritis (OA) of the knee.1,2 There are 2 main types of HTO surgery: lateral closed-wedge high tibial valgus osteotomy (CWHTO) 3 and medial open-wedge high tibial valgus osteotomy (OWHTO). 4 At present, an increasing number of surgeons use OWHTO because it is comparatively simpler. OWHTO is most effective during the early or middle stages of knee OA but is not expected to have a beneficial impact if the knee OA is accompanied by a severe deformity or in cases of patellofemoral joint OA.There are several disadvantages to traditional CWHTO including lateral-offset increases due to horizontal osteotomy and loss of the large bone block below the lateral tibial plateau. Discrepancies in the leg length arise after CWHTO because the operative side is shortened. 5,6 It also takes a relatively long time to achieve bone union at the osteotomy site after CWHTO because of discrepancies between the area on the proximal and distal fragments. This creates difficulties in maintaining alignment until bone union is acquired. Full weight bearing is also difficult until the osteotomy site is united, and a long leg cast or knee brace is thus needed for CWHTO patients.Optimal postoperative rehabilitation after knee surgery is needed to enable walking with full weight without any support as soon as possible. This, in turn, will prevent the aggravation of osteoporosis, the deterioration of physical function, and the onset of deep vein thrombosis after surgery. We describe a new surgical procedure combining OWHTO and C...