CHANGES IN THE POSTERIOR TIBIAL SLOPE AND PATELLAR HEIGHT IN MEDIAL OPENING WEDGE HIGH TIBIAL OSTEOTOMIES: ARE THEY INEVITABLE OR SURGICAL ERRORS?

Abstract

AbstractIntroductionChanges in posterior tibial slope (PTS) and patellar height (PH) following proximal tibial osteotomies have been a recent focus for knee surgeons. Increased PTS and decreased PH following medial opening wedge high tibial osteotomy (MOWHTO) have been repeatedly reported in the literature. However, this has been disputed in more recent biomechanical studies.MethodologyA total of 62 cases who underwent MOWHTO were included. Surgery was performed using a dedicated step-by-step protocol focusing on the risks of unintentional slope changes. Clinically, all patients were evaluated preoperatively and at 2 years follow-up with the KOOS scores and UCLA physical activity scale. Preoperative and postoperative radiographic lower limb alignment parameters were measured on full-length lower limb radiographs, including (HKA), (MPTA), (mLDFA), proximal posterior tibial angle (PPTA), (JLCA) and(JLO). PH measurements were assessed on radiographs.ResultsThere was a significant change in the coronal plane alignment; the mMPTA changed from 84.38° to 90.39°, and the HKA changed from 172.19° to 180.15° (Both P < 0.0001). There was no significant change in the PTS as evidenced by a postoperative PPTA of 80.56 ° from a preoperative of 80.36°. And no significant change in the PH with all the indices; preoperative Caton Deschamps, Insall Salvati, and Schröter indices measured 0.95, 1.03, and 1.56, respectively. In comparison to postoperative measures of 0.93, 1.03, and 1.54, respectively.ConclusionMOWHTO does not change the PTS or PH when accurate preoperative planning and precise intraoperative freehand technique are adopted. Involuntary modification of these anatomic parameters should be considered surgical errors.