Summary
In a randomized controlled trial with inclusion of 85 patients and follow-up until five years postoperatively ACL repair was compared to ACL reconstruction and no significant difference was found regarding instrumented knee joint laxity and patient reported outcome, although a careful patient selection seems necessary for ACL repair to control the rate of recurrent ACL insufficiency.
Abstract
Purpose
Anterior cruciate ligament (ACL) repair has experienced a renaissance in the past decade due to technical innovation and satisfying functional results and healing rates in cohort studies. The present study aimed to compare the results of ACL repair in comparison to primary ACL reconstruction for acute isolated ACL tears until five years postoperatively. It was hypothesized, that ACL repair would yield comparable functional results, knee joint stability and recurrent instability rate in relation to ACL reconstruction.
Methods
85 patients with acute ACL tears were randomized to undergo either ACL repair using dynamic intraligamentary stabilization or primary ACL reconstruction with a semitendinosus tendon autograft. Side-to-side difference of anterior tibial translation (delta-ATT) was assessed by Rolimeter testing and was defined as the primary outcome measure. Patient reported outcome was acquired using the Tegner activity scale, the International Knee Documentation Committee (IKDC) subjective score and the Lysholm score at each follow up. The pre-injury activity level and knee joint function were recorded, and the preoperative delta-ATT was measured. Short- and mid-term outcome was assessed at one, two and five years postoperatively. The rate of recurrent instability and other complications were recorded. A power analysis was performed a priori, and Friedman test, Mann-Whitney-U test and Bonferroni correction were applied for statistical comparisons.
Results
The overall follow-up rate was 100% at one year, 98% at two years and 73% at five years postoperatively. After five years, delta-ATT was 1.7 ± 1.6 mm in the ACL repair group and 1.4 ± 1.3 mm in the ACL reconstruction group (p = n.s.). Pre-injury knee function assessed by Tegner, Lysholm and IKDC subjective score was restored as soon as one year after surgery in both groups and maintained until two and five years postoperatively. No significant difference regarding patient reported outcome measures was found between ACL repair and ACL reconstruction at any time of the follow-up (P = n.s.).
Recurrent instability was found in twelve cases (28%) after ACL repair in comparison to six cases (14%) after ACL reconstruction (P = n.s.). ACL revision surgery was performed in ten cases after ACL repair (23%) and consisted of single-stage revision reconstruction with hamstring autografts in each case. In the ACL reconstruction group, five patients underwent a two-staged ACL revision surgery due to tunnel widening. Recurrent instability was associated with young age (< 25 years) and higher Tegner scores (> 6) in both groups.
Conclusion
Until five years after ACL repair no significant difference was found regarding instrumented laxity and patient reported outcome, in comparison to ACL reconstruction. However, the rate of recurrent ACL insufficiency was increased after ACL repair. In the revision situation, single-stage revision was possible in all cases following primary repair, whereas after primary reconstruction, a two-staged revision had to be performed in five cases. The present study supports the use of ACL repair as an alternative treatment for acute ACL injuries.