May smokers and overweight patients be treated with a medial open-wedge HTO? Risk factors for non-union.

Purpose: The purpose of this retrospective study was to investigate the rate of non-union after medial open-wedge high tibial osteotomy (HTO) with the Tomofix(®) plate. In addition, risk factors with a possible influence on the development of a non-union were analysed.
Methods: Between 2006 and 2008, a total of 186 medial open-wedge HTOs were performed in 182 patients.
Results: Ten cases of non-union (5.4%) were recorded. Risk factors with a statistically significant influence on the development of a non-union included smoking, body mass index and fracture of the lateral cortical hinge. No influence was detected for the factors age, degree of correction, concomitant diseases, postoperative complications, drug use, additionally performed procedures and use of a temporary lag screw.
Conclusion: Within this study, it could be demonstrated that the rate of non-union in medial open-wedge HTO is not higher than in the lateral closed-wedge technique. Concerning the detected risk factors, the importance of the preservation of the lateral cortex is emphasised. In addition, it is necessary to discuss the risk of non-union with smokers and overweight patients when planning the therapy. Finally, it should be considered to perform iliac crest bone grafting in these high-risk patients a priori.