Is a synthetic augmentation in medial open wedge high tibial osteotomies superior to no augmentation in terms of bone-healing?

•Augmentation of osteotomy gap after medial open wedge high tibial osteotomy = MOWHTO•Nineteen patients with synthetic bone graft, 30 patients without augmentation•Bone healing was assessed and compared within the two groups.•Results revealed significant more non-unions in patients with synthetic bone graft.•Recommendation: no use of synthetic bone graft after MOWHTO.

IntroductionMedial open-wedge high tibial osteotomy (MOWHTO) is an established method to treat unicompartimental osteoarthritis of the knee joint. However, augmentation of the created tibial gap after osteotomy is controversially discussed.MethodsWe performed a prospective investigation of 49 consecutive cases of MOWHTO at our department. Patients were divided into two groups: group A consisted of 19 patients while group B consisted of 30 patients. In group A, the augmentation of the opening gap after osteotomy was filled with a synthetic bone graft, whereas group B received no augmentation. As an indicator for bone healing we investigated the non-union rate in our study population and compared the non-union-rate between the two groups.ResultsThe non-union rate was 28% in group A (five of 19 patients had to undergo revision) which received synthetic augmentation, while it was 3.3% in group B (one of 30 patients had to undergo revision) which received no augmentation. The difference between the groups was statistically significant (p-value 0.027).ConclusionsWith regard to bone healing after MOWHTO, synthetic augmentation was not superior to no augmentation in terms of non-union rates after surgery. In fact, we registered a significantly higher rate of non-union after augmentation with synthetic bone graft.Level of evidenceIII