Influence of Graft Type on Lower Extremity Functional Test Performance and Failure Rate After Anterior Cruciate Ligament Reconstruction

Background: Both autografts and allografts are used to reconstruct the anterior cruciate ligament (ACL) after injury; however, it is unclear whether graft source affects lower extremity functional test performance or failure rate in an active military population.

Objective: To compare lower extremity functional test performance and graft failure rates between ACL grafts [allograft, hamstring, bone-patellar tendon-bone (BTB)].

Study design: Cross-sectional.

Level of evidence: Level 2.

Methods: Ninety-eight cadets entering a US Service Academy with a history of unilateral ACL reconstruction (ACLR) agreed to participate. Before basic training, participants completed 4 lower extremity functional tests. Active injury surveillance was conducted within the study cohort to identify all subsequent graft failures.

Results: Cadets with hamstring autografts outperformed the BTB and allograft groups on the Lower Quarter Y-Balance Test-Posteromedial direction and single-leg hop test, respectively. No differences were detected by graft type for the other functional tests. The incidence of subsequent ipsilateral graft failures in patients with autograft was 8.11%. No failures were observed in the allograft group during the follow-up period. After controlling for sex, joint hypermobility, and time since injury and surgery, the risk of graft failure was 9.8 times higher for patients with a hamstring autograft than with a BTB (P = 0.045).

Conclusion: After ACLR, graft type appears to influence some single-limb measures of lower extremity function and the risk of subsequent failure. Hamstring autografts demonstrated better functional performance but increased risk of graft failure.

Clinical relevance: Surgeons need to weigh the pros and cons of all graft options in relation to the patient's lifestyle. Regardless of graft type, individuals with an ACLR may require additional rehabilitation to regain neuromuscular control during dynamic single-limb tasks and mitigate graft failure.