79. L’ostéotomie tibiale antérieure de déflexion avec préservation de la TTA ne modifie pas la hauteur rotulienne.

Anterior-closing wedge high tibial osteotomy (ACW-HTO) in ACL reconstruction (ACLR) can prevent graft rupture in patients with posterior tibial slope (PTS) > 12°. Management of patellar height is of concern when performing HTO. The objective was to evaluate the effect of tibial tubercle-sparing ACW-HTO on patellar height in revision ACLR.

A retrospective analysis of prospectively collected data from 2 centers was performed. All patients who underwent tibial tubercle-sparing ACW- HTO in revision ACLR were identified and included. Data regarding age, gender and body mass index were collected. Patellar height was measured on full weightbearing pre- and post-operative x-rays. The tibial-referenced indexes of Insall-Salvati (ISI), Caton-Deschamps (CDI) and Blackburne-Peel (BPI) were assessed on lateral x-rays. The Femoral Patellar Height Index (FPHI), femur-referenced, was calculated on frontal x-rays. Pre- and post-operative PTS were assessed using the proximal anatomic axis of the tibia and the tangent line to the medial tibial plateau. All radiological measurements were performed by two trained sports medicine physicians, twice at three-month intervals. Mean values were retained for statistical analysis. Inter and intra-observer reliability were assessed for each parameter.

47 tibial tubercule-sparing ACW-HTO were retained for analysis. Most patients were male (n = 32, 68.1%) with a mean age of 28.9 ± 9.2 years old (range 17 – 58). Good to excellent intra- and inter-observer reliability were reported for all parameters. The mean decrease in PTS was 8.60° ± 2.95 (range 3 – 13.6). No significant difference in patellar height was found between pre- and postoperative x-rays regardless of the index (P > .05). Linear regression investigated the influence of change in slope (delta PTS) on change in patellar height (delta and ratio). No influence of delta PTS was found on all parameters except on the CDI ratio (ratio = pre-operative/post-operative, P = .0088). Multivariate analysis showed a significant influence of delta PTS on the CDI ratio (P = .0335), but none on the ISI (P = .7037), BPI (P = .6324), and FPHI (P = 5709) ratios.

A change in PTS appeared to influence the Caton Deschamps Index, but this tibial plateau-referenced method may be biased after HTO. No change in patellar height was observed with others index after tibial tubercle-sparing ACW-HTO.