Summary
The use of a hamstring tendon autograft, younger age, meniscal repair at time of primary ACL reconstruction and shorter time from injury-to-surgery were predictive factors for a reoperation.
Abstract
Introduction
Reoperation following primary anterior cruciate ligament (ACL) reconstruction may be required for a variety of different reasons. The aim of this study was to combine data from a national ligament registry with data from a national insurance claims database to identify the rate, reasons, and risk factors for reoperation following primary ACL reconstruction.
Methods
Prospective data recorded by the New Zealand ACL Registry was analyzed and cross referenced with data from the Accident Compensation Corporation (ACC), which is the New Zealand Government’s sole funder of ACL reconstructions and any subsequent surgery. Primary ACL reconstructions performed between April 2014 and September 2019 were analyzed. Patient and surgical data including age, sex, time from injury-to-surgery, a history of previous knee surgery, graft type, concomitant meniscal injury and femoral tunnel drilling technique were analyzed as recorded in the New Zealand ACL Registry. The ACC database was used to identify patients who underwent a subsequent reoperation. A manual review of operation notes was performed to identify the reason for reoperation and the procedures performed. Univariate Chi-square test and multivariate Cox regression survival analysis were performed to identify independent risk factors for all-cause reoperation. Adjusted hazard ratios (aHR) with 95% confidence intervals (CI) were computed.
Results
A total of 8046 primary ACL reconstructions were matched between the New Zealand ACL Registry and ACC databases. The rate of reoperation was 8.9% (n = 715) at a mean follow-up of 2.5 years. There were 131 reoperations that involved more than one procedure. The most common procedures performed during a reoperation were related to the meniscus in 3.7% (n = 299), revision ACL reconstruction in 2.7% (n = 219), arthrofibrosis in 2.3% (n = 185), cartilage in 0.7% (n = 56) and implant-releated issues in 0.4% (n = 32). Of the 219 revisions recorded in the ACC database, the New Zealand ACL Registry captured 208 (95%). The use of a hamstring tendon autograft was associated with a 1.4 times higher risk of reoperation when compared to the patellar tendon autograft (9.5% versus 6.9%, aHR = 1.4, p<0.001). The rate of reoperation was higher in patients aged <20 years (11.2%, aHR = 1.6, p<0.001) and in patients aged between 21-30 years (9.8%, aHR = 1.4, p<0.001) when compared with patients aged >30 years (6.2%). Patients who had a repair of the medial or lateral meniscus during their primary ACL reconstruction were more likely to require a reoperation when compared to patients who had a normal meniscus (medial repair aHR = 1.9, p<0.001; lateral repair aHR = 1.3, p = 0.02). Lastly, when compared with patients under underwent surgery within 6 weeks (reoperation rate = 12%), a lower risk of reoperation was observed in patients who underwent surgery between 6 weeks and 6 months (9.3%, aHR = 0.8, p = 0.05) or more than 6 months after their index injury (7.4%, aHR = 0.6, p<0.001). Patient sex, a history of previous knee surgery and femoral tunnel drilling technique were not associated with the risk of reoperation.
Conclusion
The New Zealand ACL Registry captured over 95% of revision ACL reconstructions. Meniscal-related procedures were the most common reason for reoperation following primary ACL reconstruction. The use of a hamstring tendon autograft, younger age, meniscal repair at time of primary ACL reconstruction and shorter time from injury-to-surgery were predictive factors for a reoperation.