Validation of a Composite Test for Assessment of Readiness for Return to Sports After Anterior Cruciate Ligament Reconstruction: The K-STARTS Test

BACKGROUND: There is limited information on the appropriate timing of return to sports after anterior cruciate ligament (ACL) reconstruction. A composite test was developed to assess the athlete’s ability to return to sports after ACL reconstruction: the Knee Santy Athletic Return To Sport (K-STARTS) test. HYPOTHESIS: The K-STARTS test meets validation criteria for an outcome score assessing readiness for return to sports after ACL reconstruction. STUDY DESIGN: Diagnostic study. LEVEL OF EVIDENCE: Level 3. METHODS: A prospective comparative study identified 410 participants: 371 participants who had undergone ACL reconstruction and a control group of 39 healthy participants. The K-STARTS score is calculated as the sum of 7 tests (8 components), for a maximal value of 21 points. Construct validity, internal consistency, discriminant validity, and sensitivity to change were used to validate this new test. RESULTS: The K-STARTS assessment showed a high completion rate (100%), high reproducibility (intraclass correlation coefficient, 0.87; coefficient of variation, 7.8%), and high sensitivity to change. There was moderate correlation with the ACL Return to Sports after Injury scale (ACL-RSI) and hop tests. There were no ceiling or floor effects. There was a significant difference between K-STARTS scores assessed at 6 and 8 months postoperatively (11.2 ± 2.7 vs 17.1 ± 3.2; P < 0.001). The K-STARTS score in the control group was significantly higher than that in the ACL reconstruction group (17.3 ± 2.1 and 13.7 ± 3.8, respectively; P < 0.001). CONCLUSION: The K-STARTS test is an objective outcome measure for functional improvement after ACL reconstruction. CLINICAL RELEVANCE: It is important for the clinician to determine when return to sports is optimal after ACL reconstruction to reduce the current high risk of reinjury.