Effect of Graft Choice on Revision and Contralateral Anterior Cruciate Ligament Reconstruction: Results From the New Zealand ACL Registry

Background: The patellar tendon is often considered the “gold standard” graft for reducing the risk of graft rupture after anterior cruciate ligament (ACL) reconstruction. However, its use may also be associated with an increased risk of injury to the contralateral ACL. Purpose: To clarify the association between graft choice and the risk of revision and contralateral ACL reconstruction. Study Design: Cohort study; Level of evidence, 2. Methods: Prospective data captured by the New Zealand ACL Registry between April 2014 and December 2018 were reviewed. All primary ACL reconstructions performed using either a hamstring tendon or patellar tendon autograft were included. Cox regression survival analysis adjusting for patient factors was performed to compare the risk of revision and contralateral ACL reconstruction between the hamstring tendon graft and the patellar tendon graft. Results: A total of 7155 primary ACL reconstructions were reviewed, of which 5563 (77.7%) were performed using a hamstring tendon graft and 1592 (22.3%) were performed using a patellar tendon graft. Patients with a hamstring tendon graft had a revision rate of 2.7% compared with 1.3% in patients with a patellar tendon graft (adjusted hazard ratio HR, 2.51; 95% CI, 1.55-4.06; P < .001). The patellar tendon graft was associated with an increased risk of contralateral ACL reconstruction compared with the hamstring tendon graft (adjusted HR, 1.91; 95% CI, 1.15-3.16; P = .012). The number needed to treat (NNT) with a patellar tendon graft to prevent 1 revision was 73.6. However, the NNT with a hamstring tendon graft to prevent 1 contralateral reconstruction was 116.3. Conclusion: Use of a patellar tendon graft reduced the risk of graft rupture but was associated with an increased risk of injury to the contralateral ACL. Adequate rehabilitation and informed decision making on return to activity and injury prevention measures may be important in preventing subsequent injury to the healthy knee.