Midterm Quadriceps Strength Outcomes of Revision ACL Reconstructions Comparing Ipsilateral Extensor Mechanism Autografts and Hamstring Tendon Autografts

Background: Primary anterior cruciate ligament reconstructions (ACLRs) with extensor mechanism autografts (bone–patellar tendon–bone [BTB] or quadriceps tendon [QT]) have been reported to have lower quadriceps strength symmetry outcomes 6 months postoperatively as compared with those using a hamstring tendon (HT) autograft. However, the influence of a recurrent ipsilateral extensor mechanism graft harvest for a revision ACLR on quadriceps strength symmetry recovery is not well known. Purpose: To investigate the effect of ipsilateral revision ACLR autograft selection on the recovery of quadriceps limb symmetry index (Q-LSI) 6 months after a revision ACLR. Study Design: Cohort study; Level of evidence, 3. Methods: After revision ACLR, 53 patients were divided into 3 groups based on the ipsilateral autograft utilized for the primary and revision ACLR: hamstring to extensor (HT/Ext; ie, BTB or QT), extensor to hamstring (Ext/HT), and extensor to extensor (Ext/Ext). Six months after revision ACLR, patients completed an isometric quadriceps strength testing protocol on an isokinetic dynamometer; Q-LSI and quadriceps peak torque relative to body weight were then calculated and used for analysis. Separate analyses of covariance were conducted for each outcome using a multivariable linear regression framework, with group as the primary independent variable and age, sex, body mass index, and time since surgery included as covariates. Results: The Ext/HT group exhibited significantly greater quadriceps strength symmetry (Q-LSI = 88%) than the Ext/Ext group (Q-LSI = 69%; P = .028) and the HT/Ext group (Q-LSI = 70%; P = .005) 6 months after a revision ACLR. At the 6-month testing timepoint after a revision ACLR, no significant differences in Q-LSI were observed between the Ext/Ext group (Q-LSI = 69%) and HT/Ext group (Q-LSI = 70%; P = .99). Conclusion: As compared with HT autografts, an ipsilateral BTB or QT autograft for a revision ACLR is associated with significantly lower Q-LSI values at the 6-month postoperative timepoint, regardless of the autograft type used for the primary ACLR.