Lateral Closing-Wedge Osteotomy Achieved More Accurate Correction Than Medial Opening-Wedge Osteotomy

Abstract

Question: In patients having high tibial osteotomy, how do lateral closing-wedge and medial opening-wedge techniques compare with regard to achievement and maintenance of correction? Design: Randomized (allocation concealed)*, un-blinded, controlled trial with 1-year follow-up. Setting: A university medical center in Rotterdam, The Netherlands. Patients: 92 patients (mean age 50 y, 64% men) with radiographic evidence of medial compartment osteoarthritis of the knee with medial joint pain and varus malalignment. Patients with symptomatic osteoarthritis of the lateral compartment, rheumatoid arthritis, range of movement of 10° were excluded. Patients in whom both knees were symptomatic had only the first knee included. 91 patients (99%) completed the study. Intervention: 47 patients were allocated to closing-wedge high tibial osteotomy and a plaster cylinder cast for 6 weeks after surgery, and 45 patients were allocated to opening-wedge osteotomy fixed with use of a Puddu plate (Arthrex, Naples, Florida). The closing-wedge technique was performed with use of the Allopro (Zimmer, Winterthur, Switzerland) calibrated osteotomy guide to resect the bone. The common peroneal nerve was exposed and retracted, and the anterior part of the fibular head was resected. The osteotomy was fixed with 2 staples. A fasciotomy of the anterior compartment was done to prevent compartment syndrome. For the opening-wedge technique, the extent of the opening wedge was calculated preoperatively with use of the goniometric formula table in the Arthrex instruction manual. During the procedure, the degree of correction was controlled by fluoroscopic assistance. If the opening-wedge was >7.5 mm, the open gap was filled with bone harvested from the ipsilateral iliac crest. Patients in the opening-wedge group were also randomized to receive a plaster cast (n = 22) or no cast (n = 23) after the osteotomy. Main outcome measures: Achievement of an overcorrection of the hip-knee-ankle angle by 4° ofvalgus (difference between the achieved valgus correction and the objective of 4° ofovercorrection). A dichotomous outcome of the proportion ofpatients achieving a valgus alignment between 0° and 6° was also measured. Secondary outcomes were measures of pain (visual analog scale [VAS]), walking distance, and knee function (Hospital for Special Surgery [HSS] score). The HSS score measured pain, function, range of movement, muscle strength, flexion deformity, and instability and involved a questionnaire and a physical examination. Main results: Analysis was by intention to treat. At 1 year, the hip-knee-ankle angle was greater in the closing-wedge group than in the opening-wedge group (3.4° vs 1.3°, respectively, with an adjusted mean difference of 2.12° [95% confidence interval, 0.38 to 3.86]). The mean deviation from valgus alignment of 4° was less in the closing-wedge group than in the opening-wedge group (2.7° vs 4°, respectively, with an adjusted mean difference of 1.67° [95% confidence interval, 0.42 to 2.92]). A valgus alignment within 0° to 6° was achieved in more patients in the closing-wedge group than in the opening-wedge group (Table).