The high tibial osteotomy is a well-established and commonly used treatment for active patients with medial unicompartmental osteoarthritis or cartilage lesion of the knee and varus malignment. Development of new implants and improvement of the surgical technique led to widespread use of the procedure. High complication rates are reported. The result depends on the precision of the correction, partially. Reports of an advantage of the navigation tool are available, however, the level of evidence was low. Primary biomechanical stability of implants and radiostereometry analysis encourage to early full weight bearing after open wedge HTO. Improvement of clinical scores could not be observed in published studies.
The purpose of the study was to examine the precision of the navigation compared to the digital planning in open wedge HTO. Primary outcome was the difference of the mechanical tibiofemoral angle (mTFA) compared the planning and the 6 weeks follow-up measurements (full weight bearing long leg radiographs). Secondary outcome was defined as clinical results depending on the different groups (surgical experience, aftercare, implant).
Overall n=120 patients were planed to include in the study (n=60 navigation and n=60 non navigation). The patients were randomized according the different groups. Open wedge HTO was performed according the well-known technique. The surgery was performed in n=60 cases by an experienced surgeon (consultant) and in n=60 by a non-experienced surgeon (resident). This assignment was not randomized. If the OrthoPilot® navigation tool was used the aim of the correction was guided by the navigation tool. If the surgical procedure was performed without the navigation tool the height of the osteotomy gap was measured and adjusted according the digital planning. Fixation was performed using the POSITION HTO plate or the TomoFix-plate. Postoperatively, the patients were allowed to full weight bearing after 6 weeks or after 11 days.
The POSITION HTO plate (Aesculap, Braun, Tuttlingen, Germany) represent short spacer plates and could not be recommended. Higher stability of the TomoFix-plate is known and recommended for fixation of the osteotomy. Using the navigation tool (OrthoPilot®) did not improve the precision of the osteotomy, however, the time of surgery was longer and the costs are higher. Early full weight bearing is recommended to improve the clinical outcome much earlier.
-cross sectoral-Type of hazard:
rehabilitationDescription, key words:
OrthoPilot, Osteotomy, TomoFix, POSITION HTO