Background: Determining the long-term risk of arthritis in patients with anterior cruciate ligament (ACL) injury treated nonoperatively versus those who undergo ACL reconstruction (ACLR) remains an important and unanswered question for patients and surgeons. Purpose: (1) To define the cumulative arthritis rate and severity after nonsurgical management of ACL injury—the chronically ACL-deficient (ACLD) knee; (2) to compare rates and severity of arthritis in patients who have ACLD knee with similar patients who underwent ACLR; and (3) to identify clinically relevant risk factors for arthritis. Study Design: Systematic review; Level of evidence, 3. Methods: Three databases (Medline, Embase, PubMed) were searched for primary studies examining radiographic outcomes in patients with chronic ACL deficiency (>12 months of ACL deficiency). Studies with a matched ACLR control group were included. Quality assessment was performed with the MINORS (Methodological Index for Nonrandomized Studies) tool. Arthritis prevalence over time was plotted and modeled to best-fit using the Akaike information criterion. Data were extracted for meta-analysis for the primary outcome of osteoarthritis. The cumulative odds ratio of prognostic factors was calculated where appropriate. Results: Nineteen full-text studies met inclusion criteria (11 matched cohort studies comparing ACLD and ACLR) including 1432 patients with a mean 11.1 years of follow-up after injury. The methodological quality of included studies was moderate. The pooled rate of radiographic arthritis in ACLD patients was 37.8%; the rate of moderate to severe arthritis was 18.1% (compared with 35.2% and 12.8% in patients with ACLR, respectively, and 5.0% in the nonoperated knee). An increase in the rate of arthritis was observed, accelerating sharply at 10 years after injury. ACLR and ACLD knees had similar prevalence of mild arthritis ( P = .60), irrespective of activity level. Joint degeneration was significantly accelerated by meniscectomy in ACLD patients in most studies. Conclusion: Patients with a chronically ACLD knee may be at an increased predisposition for developing moderate to severe arthritis but not mild arthritis compared with matched patients who undergo ACLR. Meniscectomy is a key predictor of worsened severity of osteoarthritis.
Shah et al. (Fri,) studied this question.