High tibial osteotomy: closed wedge versus combined wedge osteotomy

Background: High tibial osteotomy is a common procedure to treat symptomatic osteoarthritis of the medial compartment of the knee with varus alignment. This is achieved by overcorrecting the varus alignment to 2-6 of valgus. Various high tibial osteotomy techniques are currently used to this end. Common procedures are medial opening wedge and lateral closing wedge tibial osteotomies. The lateral closing wedge technique is a primary stable correction with a high rate of consolidation, but has the disadvantage of bone loss and change in tibial condylar offset. The medial opening wedge technique does not result in any bone loss but needs to be fixated with a plate and may cause tibial slope and medial collateral ligament tightening. A relatively new technique, the combined valgus high tibial osteotomy, claims to include the advantages of both techniques without bone loss. Aim of this prospective randomized trial is to compare the lateral closing wedge with the combined wedge osteotomy in patients with symptomatic varus osteoarthritis of the knee. Methods/design: A group of 110 patients with osteoarthritis of the medial compartment of the knee with 6-12 varus malalignment over 18 years of age are recruited to participate a randomized controlled trial. Patients are randomized to undergo a high tibial osteotomy, with either a lateral closing wedge technique or a combined wedge osteotomy technique. Primary outcome measure is achievement of an overcorrection of 4 valgus after one year of surgery, assessed by measuring the hip-knee-ankle angle. Secondary objectives are radiological scores and anatomical changes after high tibial osteotomy; pain, functional scores and quality of life will also be compared. Discussion: Combined high tibial osteotomy modification avoids metaphyseal tibial bone loss, decreasing transposition of the tibial condyle and shortening of the patellar tendon after osteotomy, even in case of great correction. The clinical results of the combined wedge osteotomy technique are very promising. Hypothesis is that the combined wedge osteotomy technique will achieve more accurate overcorrection of varus malalignment with fewer anatomical changes of the proximal tibia after one year.