Comparison of Postoperative Strength Progression and Outcomes Following Primary Versus Secondary ACL Reconstruction in the Young Athlete.

Background: Return to sport testing after ACL reconstruction (ACLR) is becoming increasingly popular. Anecdotally, some believe that patients who undergo a second ACL surgery on either the ipsilateral or contralateral leg progress through their rehabilitation goals faster the second time through. The purpose of this study was to evaluate the rate of strength progression in return to sport testing after primary and secondary ACLR surgeries in a young, active population.

Methods: A retrospective review of patients who underwent ACLR between September 2013 and December 2022 was performed. Patients were included if they underwent an ACLR and completed at least 2 postoperative strength tests. Strength testing was commonly performed at 3, 6, and 9 months. Exclusion criteria included age older than 30 and those who had a contralateral graft harvest. Structural equation modeling was performed for each strength assessment by the timepoint it was performed. A linear combination of parameters was performed to compare the path coefficients between the primary and secondary ACL groups for each strength test to assess statistical differences in the rate of change of each strength test over time.

Results: Three hundred ninety-six patients in the primary ACLR group and 50 patients in the secondary ACLR group met the inclusion criteria. Patients who received secondary ACL surgery were older, had a higher percentage of BTB grafts, lateral augments, and internal brace augments. Months from surgery had a significant positive correlation with nearly all strength tests in both groups. There was no difference between primary and secondary surgery in the progression of any postoperative strength test. There was no difference in progression of IKDC or RSI scores between groups.

Conclusion: This study suggests that patients who undergo a second ACL surgery do not progress their strength faster or slower than after primary ACLR. This implies that these patients do not require different return-to-play protocols from a strength perspective.

Level of evidence: Retrospective study, level III evidence.