2. La lésion des structures antérolatérales du genou est le facteur de risque le plus important du Pivot Shift de haut Grade dans les ruptures récentes du LCA.

Background:Pre-operative high-grade pivot shift is associated with higher rates of ACL graft failure, persistent instability and inferior patient reported outcomes. The pathophysiology of high-grade pivot shift is multifactorial and numerous factors have been implicated. 

Purpose :The aim of this study was to determine risk factors for high-grade pivot shift, with a particular emphasis on addressing the limitations of previous studies, by including a comprehensive evaluation of both soft-tissue and osseous parameters. 

Study design: Case series 

Methods :A prospective evaluation of 200 consecutive patients undergoing acute ACL reconstruction (within 10 days of injury) was undertaken. An open lateral exploration was undertaken at the time of the index procedure. Details regarding patient and injury characteristics were recorded. Osseous parameters (tibial slope and condylar ratios) were determined using established MRI protocols. A multivariate logistic regression with Penalized Maximum Likelihood was used to identified risk factors associated with grade 3 pivot shift. A stepwise descending strategy was applied from the initial full model to determine the most parsimonious one, removing step-by-step all the non-statistically significant parameters and keeping only the clinically relevant parameters and confounding factors (if any). 

Results :The mean age of the population was 28.3 +/- 9.8 years. 67.5% of patients were male. 35 (17.5%) of patients had a high grade (grade 3) pivot shift and 165 (82.5%) had a low-grade pivot shift (grades 1 and 2). Both uni- and multivariate analyses demonstrated that injury to the Anterolateral structures of the knee was the only significant risk factor for high grade pivot shift. When this was subcategorized further, it was identified that both complete and incomplete tears of the ALL, and Segond fractures were all significant risk factors for high grade pivot shift. 

Conclusions :A comprehensive evaluation of soft-tissue and osseous factors has identified that injury to the Anterolateral Structures of the knee is the most important risk factor for explosive pivot shift in acute ACL-injured knees.