| Objective:Return to sport(RTS)safely is one of the main goals for patients after anterior cruciate ligament reconstruction(ACLR),and objective,quantitative assessment is essential to guide patients to return to sport safely.However,there is a lack of objective test battery for RTS,and it is unclear which functional indicators(e.g.,knee kinematics)can predict return to sport after surgery and whether there is a correlation between the functional indicators.Therefore,the objectives of this study were:(i)to develop a test battery which contains knee kinematics tests and analyze the predictors of successful return to sport in patients after ACLR based on the results of a comprehensive assessment.(ii)to investigate whether there is a correlation between the results of each functional test,and to provide a reference basis for clinical treatment of knee functional deficits from multiple perspectives.Methods:Forty-five patients admitted to the Department of Orthopaedic Surgery of the First Affiliated Hospital of Naval Medical University after ACLR from June 2020 to October 2021 were selected,and all information was collected,and all subjective and objective tests of knee function were performed from 6 to 9 months after surgery.Subjective assessments include International Knee Documentation Committee(IKDC)and Anterior Cruciate Ligament Return to Sport after Injury(ACL-RSI)questionnaires.Objective assessments include isokinetic test,assessing the maximum knee flexion and extension moments of the affected and healthy knee and calculation of the limb symmetry index(LSI,healthy side/ affected side * 100%);single and triple hop tests for distance and calculating the LSI;Knee kinematics test,which tests the six degrees of freedom(6DOF)of the knee joint during treadmill gait and analyses the range of motion(ROM)and peak in one gait cycle and the stance phase,calculating the side-to side difference(SSD);ligament laxity test,which measures SSD between the healthy and affected side of tibial displacement relative to the femur under the same load at rest.1.One year post-operatively,an interview and Tegner score were used to assign patients to RTS and non-RTS(n RTS)groups.Multivariate logistic regression and receiver operating characteristic analyses were performed to identify the independent predictors and cut-off of RTS.2.Analyzing the relationships of multiplanar knee kinematics during the gait cycle and psychological readiness to quadriceps strength after ACLR.Pearson or Spearman correlation was used to assess associations between the variables.Results:1.At the one-year postoperative follow-up,4 patients were lost to follow-up and a total of 41 patients were included in the analysis.Thirty(73%)patients were allocated to RTS group and 11(27%)were allocated to n RTS group.Multivariate logistic regression model showed that the greater the single-leg hop test LSI,the greater the probability of return to sport,with statistical significance(dominance ratio OR = 1.714,95% CI 1.186-2.477,p = 0.004);the higher the ACL-RSI score,the greater the probability of return to motion,statistically significant(OR = 1.147,95%CI 1.040-1.266,p = 0.006);the greater the angular range of tibial rotation relative to the femur SSD,the lower the probability of return to motion,statistically significant was statistically significant(OR = 0.539,95% CI 0.359-0.808,p = 0.006);the greater the SSD of anterior-posterior translation of the tibia relative to the femur,the smaller the probability of return to motion was statistically significant(OR = 0.233,95% CI0.066-0.819,p = 0.023).ROC analysis revealed the optimal cut-off of single-leg hop test is 84.4%(sensitivity 0.867,specificity 0.818),ACL-RSI score is 44.6(sensitivity 0.815,specificity 0.818),tibial relative femoral rotation SSD is 3°(sensitivity 0.909,specificity 0.567),and tibia relative to femur anterior-posterior translation SSD is 5mm(sensitivity 0.818,specificity 0.767).2.Correlation analysis showed that the ACL-RSI score correlated negatively with interlimb differences in the knee flexion angle at IC(r = –0.35,p = 0.02)and ROM in the transverse plane(r = –0.41,p = 0.003).The LSI for quadriceps strength correlated negatively with the peak knee flexion angle(r = –0.37,p = 0.02)and positively with the ACL-RSI score(r = 0.3,p = 0.05).Conclusion:1.The knee kinematics characteristics are closely related to return to sport after ACLR,and the clinical decision-making of return to sport can be made more effectively by incorporating the kinematics test into the return to sport test battery.2.A single-hop test LSI > 84.4%,ACL-RSI > 44.6 points,knee rotational mobility SSD < 3° and anterior-posterior knee displacement SSD < 5 mm were associated with successful return to sport at 1 year postoperatively.3.Greater psychological readiness and quadriceps strength are associated with more symmetrical multiplanar knee kinematics.Psychological readiness to return to sport and strengthening of the quadriceps muscles after ACLR needs to be emphasized,which can help improve abnormal knee kinematics. |
