Validation of the Parisian Hamstring Avulsion Score (PHAS) in the Evaluation and Follow-up of Patients Operated for Proximal Hamstring Avulsion

Abstract

Background: No validated score is available for the prediction of return to sport (RTS) after proximal hamstring avulsion (PHA) surgery. Purpose: To validate a new assessment tool for patients after PHA surgery: the Parisian Hamstring Avulsion Score (PHAS). Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: All patients at our clinic who had surgery for PHA between January 2015 and March 2018 were included in this study. A suspected clinical diagnosis of PHA was confirmed by magnetic resonance imaging. PHA was repaired by surgical reinsertion with suture anchors. Minimum postoperative follow-up was 2 years, and the PHAS, University of California, Los Angeles (UCLA), score, and Tegner score were used. The PHAS is a patient-reported outcome measure, evaluating the effect of PHA injury with 9 items. It was validated by calculating its psychometric properties, and then correlation analysis was performed to determine the relationship between the PHAS, UCLA score, and Tegner score. Cutoff values for the prediction of RTS were determined. Results: A prospective case series study was performed. A total of 156 patients were included. Median age (first quartile; third quartile) was 54.2 years (44.7 years; 61.3 years), and the mean ± SD time of the final follow-up was 69 ± 11.6 months. Two years after surgery, 66.7% (n = 104) of patients were able to RTS. A strong correlation was noted between all 3 scores at 1 year postoperatively. Overall internal consistency was high, with a Cronbach alpha coefficient of 0.86. The intraclass correlation coefficient was 0.96, showing excellent reliability. The minimal detectable change was 12.9. No patients reached the maximum score at 2 years. Analysis of the receiver operating characteristic curves of the 3 scores at postoperative 9 months in relation to the RTS at 1 and 2 years showed area under the curve values of >0.7, indicating significant discriminant capacity for the RTS. A PHAS cutoff value of 86 at 9 months for the prediction of RTS at postoperative 1 year had a sensitivity of 65.6% (95% CI, 53.7%-77.5%) and a specificity of 81.4% (95% CI, 69.8%-93%). Conclusion: PHAS is a valid and reliable tool for follow-up after PHA surgery. It also offers a simple way to predict RTS.