Summary

Patients operated by high-volume surgeons report better subjective knee function two years after primary ACL reconstruction, and other factors, rather than surgeon/clinic volume, influenced subsequent revision rates, indicating that patients might benefit if operated by high-volume providers.

Abstract

Background

Anterior cruciate ligament reconstruction (ACLR) performed by high-volume surgeons and/or clinics has been associated with increased graft individualization and decreased operating times, complication rates and total costs. However, the influence of surgeon/clinic volume on subjective knee function and revision rate following primary ACLR remains unclear.

Purpose

To investigate the influence of surgeon/clinic volume on subjective knee function and subsequent ACL revision two years after primary ACLR.

Methods

Data from the Swedish National Knee Ligament Registry (SNKLR) were used to retrospectively study patients who underwent primary ACLR with autograft in 2008-2019. Surgeons and clinics were categorized into four groups respectively, based on a combination of total caseload volume (cut-off: 50 ACLRs/surgeon, 500 ACLRs/clinic) and annual volume (cut-off: 29 ACLRs/year/surgeon, 56 ACLRs/year/clinic). The Knee Injury and Osteoarthritis Outcome Score (KOOS) was analyzed, and thresholds of Minimal Important Change (MIC), Patient Acceptable Symptom State (PASS) and Treatment Failure (TF) were applied to determine if the results were of clinical meaningful importance. An adjusted multivariable logistic regression was performed to assess variables influencing MIC, PASS and TF of the KOOS4 (average score of subscales Pain, Symptoms, Sports/Recreation and Quality of Life), presented as the odds ratio (OR) with a 95% confidence interval (CI). Revision rates within two years were examined for the surgeon/clinic groups, and an adjusted Cox regression analysis was conducted to determine the hazard ratio (HR) with 95% CI of ACL revision. Other outcomes of interest were time from injury to surgery, outpatient surgery, operating time, perioperative complications and use of antibiotics and thromboprophylaxis.

Results

16,317 out of 35,371 patients completed the two-year KOOS. Patients undergoing primary ACLR by high-volume surgeons had higher MIC and PASS rates, and lower TF rates, compared to low-volume surgeons: MIC KOOS4 70.6% vs 66.3%, PASS KOOS4 46.0% vs 38.3%, TF KOOS4 8.7% vs 11.8% (all p<0.02). Significantly decreased odds of achieving MIC KOOS4 (OR 0.74, 95%CI 0.62-0.88) and PASS KOOS4 (OR 0.71, 95%CI 0.60-0.84), but not TF KOOS4, were found for ACLRs performed by low-volume compared to high-volume surgeons. Clinic volume did not influence the odds of reaching MIC/PASS/TF. 804 patients (2.2%) underwent subsequent ACL revision <2 years, with slightly higher revision rates among patients operated at high-volume compared to low-volume clinics (2.4% vs 1.7%, p<0.001). However, in the adjusted Cox regression, surgeon/clinic volume had no influence on subsequent ACL revision rates. High-volume surgeons/clinics had decreased time to surgery, operating time, perioperative complication rates, use of thromboprophylaxis and non-routine antibiotics (p<0.001)

Conclusion

Patients having primary ACLR by high-volume surgeons experienced an increased improvement and satisfaction regarding subjective knee function, compared to patients operated by low-volume surgeons. Other factors, rather than surgeon and clinic volume, were found to influence subsequent revision rates. In all, patients might benefit if operated by high-volume providers.