Factors associated with a more rapid recovery after anterior cruciate ligament reconstruction using multivariate analysis

• Limited evidence exists for prognostic factors for outcome after ACL reconstruction.
• To add to this, the present article investigated a cohort of ACL-injured athletes.
• Multivariate analysis was used to investigate prognostic parameters.
• Younger age and normal preoperative knee flexion are associated with rapid recovery after ACL reconstruction.
• Flexion and extension strength and no previous knee surgery are associated with rapid recovery after ACL-reconstruction.

BackgroundIn the past, several studies investigated factors that are prognostic or associated with outcome after anterior cruciate ligament (ACL) reconstruction. A recent review showed that only limited evidence is available for most studied factors, and that insufficient analysis methods were used commonly. Therefore, the aim of this study was to add more weight to the existing evidence, about factors that are associated with a more rapid outcome after ACL reconstruction. The second aim was to use multivariate analysis to study the possible factors independently.MethodsA cohort study was conducted with a follow-up of six months. Before surgery, patient variables were scored. Surgical variables were scored during arthroscopic ACL reconstructions with a single-bundle technique and hamstring autograft. The Lysholm score and subscales of the Knee Injury Osteoarthritis Outcome Score (KOOS) were assessed six months post surgery. A multiple analysis of variance (ANOVA) model was used to identify prognostic factors for outcome.ResultsIn total, 118 patients were included. Patients, aged ≤ 30 years, with a subjective knee score ≥ six, with normal flexion range of motion (ROM) of the knee, with flexion and extension strength deficit of ≤ 20%, and those with no previous knee surgery in the same knee at baseline scored significantly higher on outcome after multivariate analysis. No significant effect of surgical factors could be found.ConclusionYounger age, higher subjective knee score, normal knee flexion, normal knee flexion and extension strength, and no previous knee surgery in the patients' history at baseline are associated with a more rapid recovery after ACL reconstruction.Level of evidenceLevel III, prognostic study.