Comparable Instrumented Knee Joint Laxity and Patient-Reported Outcomes After ACL Repair With Dynamic Intraligamentary Stabilization or ACL Reconstruction: 5-Year Results of a Randomized Controlled Trial

Abstract

Background: Technical innovation has led to the renaissance of anterior cruciate ligament (ACL) repair in the past decade. Purpose/Hypothesis: The present study aimed to compare instrumented knee joint laxity and patient-reported outcomes (PROs) after ACL repair with those after primary ACL reconstruction for acute isolated ACL tears. It was hypothesized that ACL repair would lead to comparable knee joint stability and PROs at 5 years postoperatively in comparison with ACL reconstruction. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: A total of 85 patients with acute ACL tears were randomized to undergo either ACL repair using dynamic intraligamentary stabilization (DIS) or primary ACL reconstruction with a semitendinosus tendon autograft. The primary outcome was the side-to-side difference in anterior tibial translation (ΔATT) assessed by Rolimeter testing at 5 years postoperatively. Follow-up examinations were performed at 1, 2, and 5 years. PROs were assessed using the Tegner activity scale, the International Knee Documentation Committee (IKDC) subjective score, and the Lysholm score. Furthermore, the rates of recurrent instability, other complications, and revision surgery were recorded. A power analysis was performed a priori, and the Friedman test, Mann-Whitney U test, and Bonferroni correction were applied for statistical comparisons with significance set at P < .05. Results: The mean age at inclusion was 28.3 ± 11.5 years in the ACL repair group and 27.1 ± 11.5 years in the ACL reconstruction group. At 5 years postoperatively, a total of 64 patients (ACL repair: n = 34 of 43 [79%]; ACL reconstruction: n = 30 of 42 [71%]) were available for follow-up. At 5 years, ΔATT was 1.7 ± 1.6 mm in the ACL repair group and 1.4 ± 1.3 mm in the ACL reconstruction group ( P = .334). Preinjury PROs were restored as soon as 1 year after surgery and plateaued until 2 and 5 years postoperatively in both groups. At the 5-year follow-up, the mean Lysholm score was 97.0 ± 5.4 versus 94.5 ± 5.5 ( P = .322), respectively, and the mean IKDC subjective score was 94.1 ± 9.9 versus 89.9 ± 7.8 ( P = .047), respectively, in the ACL repair group versus ACL reconstruction group. At 5 years postoperatively, 12 patients in the ACL repair group (35%; age <25 years: n = 10/12; Tegner score ≥7: n = 10/12) had recurrent instability, of whom 10 underwent single-stage revision ACL reconstruction. In the ACL reconstruction group, there were 6 patients with recurrent instability (20%; age <25 years: n = 6/6; Tegner score ≥7: n = 5/6); however, in 5 patients, staged revision was required. Differences between both groups regarding recurrent instability ( P = .09) or ACL revision surgery ( P = .118) were not statistically significant. Recurrent instability was associated with age <25 years and Tegner score >7 in both groups. Conclusion: At 5 years after ACL repair with DIS, instrumented knee joint laxity and PROs were comparable with those after ACL reconstruction. Although no significant difference was found between repair and reconstruction, a critical appraisal of the rates of recurrent instability (35% vs 20%, respectively) and revision surgery (38% vs 27%, respectively) is needed. Young age and a high preinjury activity level were the main risk factors for recurrent instability in both groups. However, single-stage revision ACL reconstruction was possible in each case in the ACL repair group. Although ACL reconstruction remains the gold standard in the treatment of ACL tears, the present study supports the use of ACL repair with DIS as a feasible option to treat acute ACL tears in patients aged ≥25 years with low to moderate activity levels (Tegner score <7). Registration: DRKS00015466 (German Clinical Trials Register).

ACL Blasts From Past to Present

“…The 5-year results are reported in the current issue of AJSM . 15 There were no significant differences in the anterior laxity and IKDC, Lysholm, and Tegner scores between the groups. Rates of recurrent instability (repair 35%; reconstruction 20%) and revision (repair 38%; reconstruction 27%) also were not significantly different, but the magnitude of these values warrants further observation.…”

Comparable Instrumented Knee Joint Laxity and Patient-Reported Outcomes After ACL Repair: Letter to the Editor

“…We read with great interest the article titled ''Comparable Instrumented Knee Joint Laxity and Patient-Reported Outcomes After ACL Repair With Dynamic Intraligamentary Stabilization or ACL Reconstruction: 5-Year Results of a Randomized Controlled Trial,'' by Glasbrenner et al 2 We congratulate the authors on their work and the effort put into this prospective randomized controlled trial comparing dynamic intraligamentary stabilization (DIS), a novel technique for anterior cruciate ligament (ACL) repair, with traditional ACL reconstruction (ACLR).…”

Comparable Instrumented Knee Joint Laxity and Patient-Reported Outcomes After ACL Repair: Response

“…We appreciate the interest in our recent publication ''Comparable Instrumented Knee Joint Laxity and Patient-Reported Outcomes After ACL Repair With Dynamic Intraligamentary Stabilization or ACL Reconstruction: 5-Year Results of a Randomized Controlled Trial'' 7 and the opportunity to respond to the letter to the editor by Runer et al…”

“…Reasons for this were that patients moved to a different country (n = 2) or region (n = 5) or did not respond to the follow-up invitations (n = 14). 7 The decrease in followup rate during the study period reflects the difficulty of completing a 5-year follow-up in a young and active study population, with frequent changes in residency for academic or professional reasons. 7 Difference in ATT measured with the Lachman/Rolimeter test was selected during design of the study as a primary outcome measure because of its high sensitivity and diagnostic accuracy.…”