Background

Recent studies have highlighted the fact that ACL repair can lead to satisfying functional results and healing rates in the short term. Aim of the present study was to compare the mid-term functional results after ACL repair in comparison to primary ACL reconstruction for acute isolated ACL tears. It was hypothesized, that ACL repair would yield comparable functional results, knee joint stability and recurrent instability rate in relation to ACL reconstruction.

Study design:
Prospective randomized Study; Level of evidence 1

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 autograft. The preinjury activity level and function were recorded. Short- and mid-term outcome was assessed at one, two and five years postoperatively. Anterior tibial translation (ATT) was evaluated by Rolimeter testing. Tegner activity scale, the International Knee Documentation Committee (IKDC) subjective score and the Lysholm score were acquired. Furthermore, the rate of recurrent instability and other complications were recorded.

Results

Follow-up rate was >80% in both study groups. Five years postoperatively 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.). In both groups, pre-injury knee function assessed by Tegner, Lysholm and IKDC score was restored as soon as one year after surgery and maintained until two and five years postoperatively. No significant difference in terms of patient reported outcome measures was found between ACL repair and ACL reconstruction at any time of the follow-up (p = n.s.).
Eight patients (19%) of the ACL repair group presented with recurrent instability and underwent single-stage revision reconstruction with hamstring autografts. Another four patients (9%) showed increased laxity with insufficient healing after ACL repair but did not require revision. In the ACL reconstruction group, five patients (13%) sustained a re-tear after return to their previous activity level. However, in In three cases a two-staged revision was required. Recurrent instability was associated with young age and higher Tegner scores in both groups.

Conclusion

Five years after ACL repair functional results were comparable to those after 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 three of five cases.