2025 ISAKOS Biennial Congress ePoster
The Impact Of Medial Opening Wedge High Tibial Osteotomy On Patellar Height And Tibial Tubercle – Trochlear Groove Distance: Prospective Analysis Of 54 Consecutive Cases.
Coral Castillejo Iniesta, MD, Marbella, Málaga SPAIN
Giacomo Dal Fabbro, MD, Sydney, New South Wales AUSTRALIA
Margherita Bonaiuti, PhD, Bologna ITALY
Claudio Belvedere, PhD, Bologna, Bologna ITALY
Alberto Leardini, DPhil, Bologna ITALY
Fabio Norvillo, Bolonia ITALY
Alberto Grassi, PhD, Bologna ITALY
Stefano Zaffagnini, MD, Prof., Bologna ITALY
Fulvia Taddei, ENG, Bologna ITALY
Rizzoli Orthopedic Institute, Bologna, Bologna, ITALY
FDA Status Not Applicable
Summary
Medial opening wedge high tibial osteotomy decreased patellar height while did not impact on tibial tubercle-trochlear groove distance.
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Abstract
Background
Medial opening wedge high tibial osteotomy (OWHTO) is a well-recognized treatment for patients affected by knee medial compartment osteoarthritis (OA) and varus malalignment. However, the impact of OWHTO on patellofemoral (PF) stability is still controversial.
Aim
to investigate the effect of OWHTO on PF stability indices by assessing the changes in patellar height and tibial tubercle – trochlear groove (TT-TG) distance.
Methods
A prospective analysis of consecutive patients who underwent isolated OWHTO for medial knee OA (grade 2-3 according to Kellgren-Lawrence) and varus knee between 2020 and 2023 was performed. OWHTO procedure was performed with a biplanar ascending cut with respect to tibial tuberosity. Patients underwent imaging exams preoperatively and between 6 and 12 months of postoperative follow up. Patellar height was evaluated according to the Caton–Deschamps (CD) index and assessed on lateral 30° of flexion knee radiographs. TT–TG index was measured on weight bearing cone beam computed tomography (CBCT) scans (Carestream, Rochester, NY, USA) executed with the knee at 30° of flexion. Each measure was assessed twice in a blinded, randomized manner by two Authors. The statistical analysis was performed using R-studio (4.3.2, Posit PBC, Wien, Austria). To compare the differences in radiographic outcomes between pre-operative and follow-up stages, a Wilcoxon-Rank Sum test was used. Additionally, the rank-biserial effect size was calculated to provide a measure of the magnitude of the effect that is independent of sample size. The Spearman's rank correlation test was conducted to assess whether there was a significant correlation between the change of CD and the HKA correction. Statistical significance was set at p < 0.05.
Results
54 consecutive patients (100% of follow up, mean age at surgery 53.8 years, 74% males, mean BMI 27.33) were included. The mean hip-knee-ankle angle (HKA) and medial proximal tibial angle correction was of 6.5 [-8.1; -4.6] and 6.2 [-9.0; -4.6], respectively. There was excellent intraobserver and interobserver reliability of CD and TT-TG distance measurements. The median pre- and postoperative of CD index was 0.9 [0.7; 1.0] and 0.8 [0.7; 0.9], respectively, with a statistically significant difference of 0.1 [0.0; 0.1] (p <0.001). CD index decreased in 43 patients by a median value of 0.12 [0.19; 0.05]. The correlation between the change in the Caton-Deschamps index and the HKA correction was not statistically significant (p=0.834). The median pre- and postoperative of TT-TG distance was 10.5 [8.7; 13.0] and 10.0 [8.2; 12.6], respectively, without statistically significant change (0.3 [-0.7; 1.4], p = 0.661).
Conclusion
While MOWHTO decreased patellar height, such procedure did not alter TT-TG distance. These findings should be considered while planning a personalized treatment approach in patients with medial knee OA and varus knee.
Keywords: knee osteotomy; opening wedge; complications; patellofemoral instability; patella height; Caton-Deschamps; TT-TG.