Comparable Mid- to Long-term Outcomes of Semitendinosus and Semitendinosus/Gracilis Grafts in ACL Reconstruction: Median 8-Year (Range,5-10 Years) Results From a Randomized Controlled Study

Abstract

Background:

The hamstring tendon autograft used for anterior cruciate ligament reconstruction commonly entails both the semitendinosus and gracilis (ST/G) tendons for sufficient graft thickness, but they may impair function. To mitigate this, a tendon-sparing ST-only graft has been explored. However, less is known of the mid- to long-term outcomes comparing these configurations.

Purpose/Hypothesis:

The purpose was to investigate differences between the quadrupled ST tendon graft and the doubled ST/G graft configuration. The primary hypothesis was that there would be no difference in the International Knee Documentation Committee 2000 Subjective Knee Form (IKDC-SF) outcomes between groups. The secondary hypothesis was that there would be no differences in knee flexion strength, KT-1000 arthrometer side-to-side measurements, or need for secondary surgery (including revision) between the 2 techniques.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

At baseline, 98 patients were randomized to receive either the quadrupled ST tendon graft or the doubled ST/G graft configuration. Preoperatively and after 2 and median 8 years (range, 5-10 years) postoperatively, the investigators collected results for the IKDC-SF, Knee injury and Osteoarthritis Outcome Score, Tegner Activity Scale, a sports and activity participation questionnaire, knee laxity (KT-1000 arthrometer) side-to-side measurements, Lachman test, and flexion rotation drawer test. Need for secondary knee surgery was evaluated 5 to 10 years postoperatively.

Results:

Seventy-seven patients completed median 8-year follow-up (range, 5-10 years): 38 patients in the ST group and 39 patients in the ST/G group. No statistically significant differences were observed between the ST and ST/G groups in IKDC-SF scores (81.7 vs 82.1; P = .93), knee stability, or revision rates. Both groups demonstrated statistically significant improvements in self-reported function (P < .001) until final follow-up. The overall anterior cruciate ligament revision rate was 10.4%, and no increased risk of graft failure or excessive residual laxity was associated with the ST-only graft.

Conclusion:

No statistically significant differences were found between the ST group and the ST/G group in terms self-reported function, knee laxity, or need for secondary surgery at median 8 years (range, 5-10 years) after surgery. The ST-only graft configuration did not increase the risk of graft failure or excessive residual laxity compared with the ST/G graft configuration.