Increase in range of knee motion to obtain floor sitting after high tibial osteotomy for osteoarthritis

In order to obtain better range of motion in knees with osteoarthritis, medial and lateral parapatellar retinaculo-capsular release operations were performed at the time of high tibial osteotomy, with fixation using dual plating on medial compartmental knee osteoarthritis (29 knees) or spontaneous osteonecrosis of the medial femoral condyle (15 knees). At removal of the blade plate, 1 to 2 years after the initial osteotomy, the same release procedures were performed together with resection of adhesive soft tissue and resection of osteophytes, which were obstacles to full flexion. A grading system (Grade 0–3) was proposed to evaluate the duration (min) of formal floor sitting. After these procedures, the patients were able to sit on the floor with 155–165° of flexion for more than 30 min (Grade 3) in 20 knees, for 10–29 min (Grade 2) in seven, for less than 10 min (Grade 1) in nine and were unable to sit on the floor (Grade 0) in eight knees. Maximum knee flexion and total range of motion were 142±8.4° and 137±11° before and 152±6.6° and 151±7.4° after surgery, respectively. The American Knee Society Knee Score and Function Score were 61±17 and 46±16 before, and 97±5 (P<0.0001) and 91±13 (P<0.0001) after surgery at the final follow-up, respectively. The femoro-tibial angle in standing with one leg was 183±6° (3° of anatomical varus angulation) before and 170±3° (P<0.0001) (10° of anatomical valgus angulation) after surgery.