Early full weight bearing is safe in open-wedge high tibial osteotomy: RSA analysis of postoperative stability compared to delayed weight bearing

Background and purpose In open-wedge, valgus osteotomy of the upper tibia, there are concerns regarding the initial stability and ability to retain the correction. Rehabilitation protocols vary depending on the osteotomy technique and the fixation method. Angle-stable implants offer superior initial stability. Early full weight bearing appears to be possible using these implants. In this prospective cohort study, we measured migration in open-wedge osteotomy in patients following an early full weight bearing protocol and compared the results to those from a historical cohort of open-wedge osteotomy patients who followed a standard protocol (full weight bearing after 6 weeks) using radiostereometry. Methods 14 open-wedge osteotomies fixated with the angle-stable Tomofix implant were performed; patients were allowed full weight bearing as soon as pain and wound healing permitted. Radiostereometry was used to measure motion across the osteotomy at regular intervals. Improvement in pain and functional outcome were assessed postoperatively. The results were compared to those from a group of 23 patients who had undergone the same operation but had used a standard rehabilitation protocol. Results There were no adverse effects because of the early full weight bearing protocol. There were no differences in motion at the osteotomy between groups as measured by radiostereometry. In both groups, pain and function improved substantially without any differences between groups. Patients in the early weight bearing group achieved the same result but in a shorter time. Interpretation Tomofix-plate-fixated open-wedge high tibial osteotomy allows early full weight bearing without loss of correction.