Results from the Swedish national anterior cruciate ligament register

Purpose: The purpose of the study was to analyze the baseline variables and clinical outcomes for almost 24,000 patients entered into the Swedish National ACL Register between January 2005 and December 2012.

Methods: The register consists of 2 parts: 1 section in which surgeons report baseline and surgical data and 1 section in which patients report the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the EQ-5D score before and 1, 2, and 5 years after surgery.

Results: By December 2012, 23,744 patients had been entered into the surgeons' part of the register. The female-male ratio in the register is 42:58. The mean age at primary anterior cruciate ligament (ACL) reconstruction was 26 years (SD, 11 years) and 28 years (SD, 9 years) for the female and male patients, respectively. The ACL injury occurred during soccer in 36% of the female patients and 49% of the male patients. In 2012, 95% of the primary ACL reconstructions were performed using hamstring tendon autografts. For patients who had a minimum of 5 years' follow-up, the revision rate was 3.3% and the contralateral reconstruction rate was 3.8%. On all follow-up occasions up to 5 years, patients who had undergone revision had a significantly (P < .001) poorer outcome than those who had undergone primary unilateral ACL reconstructions in all KOOS and EQ-5D dimensions. On all follow-up occasions, smokers obtained significantly poorer scores than nonsmokers in terms of both the KOOS (P < .008) and the EQ-5D (P < .024).

Conclusions: Soccer is the most common cause of injury in both female and male patients, and patients undergoing revisions fare less well than those undergoing primary unilateral ACL reconstructions, as well as bilateral reconstructions. Furthermore, smokers fare less well than nonsmokers. The cumulative risk of an ACL revision or contralateral ACL reconstruction during a 5-year period is approximately 7%. For patients aged younger than 19 years, the cumulative risk is significantly higher.

Level of evidence: Level II, retrospective prognostic study.