Standscorrectie van het onderbeen door een enkelvoudige laterale gesloten wig (LGW) of een gecombineerde dubbele wig CW), bij slijtage aan de binnenzijde van het kniegewricht.

High tibial osteotomy (HTO) 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 degrees of valgus. To achieve this, different HTO techniques are being used. The most common used techniques are medial opening wedge (MOW) and lateral closing wedge (LCW) HTOs. A Cochrane review showed no

evidence whether LCW or MOW is more effective in the treatment of symptomatic medial knee OA, however the LCW is seen as the gold standard. A relatively new technique, the combined valgus producing high tibial osteotomy (CWO), claims to include the advantages of both techniques. This HTO modification avoids metaphyseal tibial bone loss, and decreases the transposition of the tibia condyle and shortening of the patellar tendon after osteotomy even in case of great correction. During the last few years, both the LCW and CWO techniques are commonly used for HTO at the department of Orthopaedics of the Martini Hospital. The clinical results of the CWO technique are very promising. However, until now, there is little scientific evidence on the effectiveness of CWO. Objective of the study: Aim of this prospective randomized trial (RCT) is to compare the gold standard LCW with the CWO in patients eligible for HTO who need a correction of 10 to 16 degrees. Hypothesis is that the CWO technique will achieve more accurate overcorrection of varus malalignment with less anatomical changes of the proximal tibia after 1 year.

Aim of this prospective randomized trial (RCT) is to compare the gold standard LCW with the CWO in patients eligible for HTO who need a correction of 10 to 16 degrees. Hypothesis is that the CWO technique will achieve more accurate overcorrection of varus malalignment with less anatomical changes of the proximal tibia after 1 year.

Preoperatively and 6 weeks, 6 months and one year postoperatively.

Patients will undergo a HTO, with either a LCW technique or a CWO technique.