Incidence and risk factors of loss of motion following anterior cruciate ligament reconstruction: a systematic review and meta-analysis

Abstract

Importance

The anterior cruciate ligament (ACL) is the most commonly injured ligament of the knee, with most patients undergoing surgical reconstruction. Of these patients, 6.5–27.6% require a second operation to treat loss of motion, which can cause substantial delays in patient recovery and return to sport. Currently, there is a paucity of comprehensive data regarding loss of motion following anterior cruciate ligament reconstruction (ACLR) surgery, resulting in variable measures of incidence and uncertainty about risk factors.

Objective

The primary objective of this study is to identify the incidence and risk factors for repeat surgical intervention for loss of motion following primary ACLR.

Evidence review

Two independent reviewers conducted a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The EMBASE, MEDLINE, and PubMed databases were searched, along with the reference lists of included articles and related systematic reviews. Studies were included if they met the following criteria: (1) included adult patients with primary ACL ruptures treated surgically, (2) had a follow-up period of at least 3 months postoperative, (3) provided an objective definition of stiffness, arthrofibrosis, or cyclops lesions, and (4) reported the incidence and/or risk factors for loss of motion. A random-effects meta-analysis was conducted to estimate the pooled incidence of loss of motion across studies.

Findings

A total of 48 studies were included in the final analysis. Of these studies, 46 reported the incidence of loss of motion requiring surgery, with a mean pooled incidence of 4% (95% CI: 3–5 ​%). The incidence decreased over time from 10% (95% CI: 7–13%) in 1991–1999 to 4% (95% CI: 3–5%) in 2000–2023. There were 29 studies that reported statistically significant risk factors for loss of motion requiring surgery. The most common risk factors were female sex, acute repair, concomitant meniscus repair, delayed postoperative range of motion, and preoperative range of motion deficit.

Conclusion

The incidence of loss of motion requiring surgery after ACLR is 4%, with a variety of risk factors related to the patient, injury, surgery, and recovery. The incidence has decreased over time, but arthrofibrosis remains a devastating surgical complication that is important to discuss with patients.

Level of Evidence

III.