Summary

ACL repair is controversial. This study compares ACL reconstructions to ACL repairs in specific proximal lesions with a good tissue quality showing comparable results. This study confirms that ACL repair may restore function with excellent results but further research is needed to select the optimal indications.

Abstract

Introduction

Proximal chronic lesions of the anterior cruciate ligament (ACL) are usually treated by ligament reconstruction. Recently, a renewed interest in primary ACL repair has raised, especially when a good ligamentous quality is still present despite the chronicity of the lesion. The topic is controversial in the literature and this prospective study aims to compare ACL primary repair with ACL reconstruction outcomes in chronic ACL-deficient knees.

Methods

36 patients operated between 2006 and 2017 for a chronic ACL proximal lesion but still a good ligamentous quality underwent an ACL transosseous repair with cortical fixation (group A). They were compared with 36 patients undergoing an ACL reconstruction with a bone-to-bone patellar tendon autograft, in close proximity to each repair surgery (group B). All patients practiced sport before injury. Mean age 34 years (range 13 to 70) in group A and 29 years (range 14 to 56) in group B. Mean time from injury to surgery 27 weeks in group A (range 4 to 260) and 55 weeks in group B (range 4 to 580).
Clinical subjective outcomes measured with Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity Scale and International Knee Documentation Committee (IKDC) subjective Score. Objective results evaluated with objective IKDC score; anterior stability determined with a KT-1000® arthrometer.
Mean follow-up of 6 years (range 1 to 10).
Statistical analysis performed with Student t-test.

Results

Group A: mean preoperative KOOS score 54,8 (SD 17,4), postoperative 92,6 (SD 13,4). Mean pre-injury Tegner Scale 6,9 (SD 1,1), after surgery 6,6 (SD 1,3). Mean subjective IKDC 46,5 (SD 17,8) before surgery and 92,7 (SD 14,2) after the repair. The postoperative objective IKDC score was A in 36 patients, with less than 3 mm of increased anterior translation with the KT-1000® arthrometer. 3 patients underwent an ACL reconstruction, two of which for a subsequent trauma.
Group B: mean preoperative KOOS score 60,2 (SD 20,7), postoperative 98,4 (SD 4,4). Mean pre-injury Tegner score 7,5 (SD 1,3), after surgery 7 (SD 1,5). Mean subjective IKDC 46,5 (SD 12,5) before surgery and 96,8 (SD 4,5) after the repair. The postoperative objective IKDC score was A for 36 patients. All the patients had less than 3 mm of increased anterior translation with the KT-1000® arthrometer. 3 patients required an ACL revision surgery for a subsequent trauma.
No significant differences were found between the two groups (p >0.05).
In both groups, one patient quit sports activity. The mean time to return to sport was 9 months (range 4 to 24) in group A and 8,4 (range 4 to 19) in group B.

Conclusions

The ACL primary repair shows good results and a failure rate of less than 10% in specific cases of chronic ACL-deficient knees with a good quality of ligamentous tissue and a proximal location of the lesion.
Re-tensioning the ACL through cortical fixation may restore knee stability with comparable functional outcomes to a control group treated with a single-bundle ACL reconstruction using a bone-to-bone patellar tendon autograft. Further research is needed to improve the selection of ideal candidates for repair.