The biological respect of the posterolateral bundle in ACL partial injuries. Retrospective analysis of 2 different surgical management of ACL partial tear in a population of high-demanding sport patients

Introduction: Most of the techniques described in the literature for the repair of chronic partial ACL tears do not spare the intact portion of the ligament. Aim of this study was to perform a retrospective analysis of the results obtained from the same ACL reconstructive surgical technique applicated by sparing or not AM bundle in a population of 42 sports patients. Materials and methods: From 2010 to 2012, 42 patients who suffered ACL partial tear injury with rupture of posterolateral bundle were randomly divided in two groups homogenous for sex, age and sport-level activities. The first group with 22 patients performed ACL reconstruction with ST-GR over-the-top technique sacrificing the anteromedial (Removing AMT Group) remaining bundle intact; otherwise, the second group with 20 patients performed the same ACL reconstruction using only ST and maintaining AM bundle (Sparing AMT Group). All the patients were followed up by MRI evaluation at 12 months and clinical evaluation with IKDC score, Tegner score at 6, 12, 24, 36, 48 and 60 months. KT-1000 instrument was performed at 12 months. The results were analyzed statistically to evaluate differences between the two groups in terms of subjective outcome, and stability and for all the tests P < 0.05 was considered significant. Results: We did not observe any failure at final follow-up. IKDC subjective score at final follow-up in Removing AMT Group was 91.2 ± 2.3 in Sparing AMT Group was 92.4 ± 2.7. Tegner score at final follow-up was 7.2 ± 2.1 for Removing AMT Group and 7.8 ± 1.8 for Sparing AMT Group. Arthrometric evaluation performed with KT-1000 at final follow-up showed a side-to-side difference of 0.9 ± 1.3 mm in the Removing AMT Group against 0.8 ± 1.0 mm in the Sparing AMT Group. Return time to the sport was 7.1 months for Removing AMT Group otherwise 6.1 months for the Sparing AMT Group. Conclusions: Both the described techniques in this study demonstrated to be able to guarantee a successful outcome. However, although no statistically significant differences were evident in terms of subjective and objective outcome between these techniques some evident benefits were evident using the sparing bundle technique in Sparing AMT Group such as better clinical scores at the final follow-up and an earlier return to sport activity.