Summary

Following primary ACL reconstruction, graft type influenced H:Q strength ratios, while male sex, younger age, lower H:Q ratio, and HT autograft (vs BPTB) were associated with increased odds of ipsilateral ACL re-injury.

Abstract

Purpose

To compare H:Q ratio between primary ACLR performed with quadriceps tendon (QT), hamstring tendon (HT), or bone-patellar tendon-bone (BPTB) autograft and assess for associations with re-rupture.

Methods

We retrospectively reviewed ACLRs performed between 2014–2024, with confirmed re-injury 2 years post-operatively. Participants completed strength assessments and patient-reported outcome measures 6-12 post-operatively. Patients undergoing multiligament reconstruction or reoperation for postoperative complications were excluded. Demographics, IKDC scores, isokinetic strength, limb symmetry, H:Q ratio, and secondary ACL injury incidences were collected. Between autograft choice, comparisons for strength and PROMs were made using ANCOVA models accounting for patient age, sex, and time since surgery. Binary logistic regression models identified predictors associated with re-injury. A sensitivity subgroup analysis excluding patients with concomitant meniscus repair or missing meniscus treatment data was also performed.

Results

A total of 584 patients were analyzed: BPTB (n=304), HT (n=164), and QT (n=116). QT patients were significantly younger (17.9±3.3 years) than BPTB and HT patients (20.2±4.3 and 20.5±6.3 years, respectively; p<0.001). QT autografts had the highest H:Q ratio (mean=86.7) compared to HT (mean=66.5) and BPTB (mean=61.4) (p<0.001) and also had the lowest quadriceps strength symmetry (75.5%). Male sex (p=0.002, OR=2.58) and younger age (p=0.044, OR=1.08) were significantly associated with ipsilateral re-injury. In the sensitivity subgroup analysis, male sex (p=0.015, OR=2.74) and lower ACL H:Q ratio (p=0.044, OR=1.02) were associated with ipsilateral reinjury, while BPTB autograft demonstrated lower ipsilateral reinjury risk relative to HT autograft (p=0.035, OR=0.38).

Conclusion

In patients with primary ACLR, graft type was associated with subsequent H:Q strength ratios. Ipsilateral ACL re-injury risk was associated with male sex and younger age. Subgroup analysis excluding patients with concurrent meniscus repair suggests male sex and lower ACL H:Q ratio are associated with greater odds of ipsilateral re-injury, while BPTB autograft had lesser odds of ipsilateral re-injury relative to HT autograft.