Development and application of a proximal hamstring MRI-based scoring tool in patients undergoing proximal hamstring tendon surgical repair

Purpose: An MRI-based scoring tool assessing surgical repair after proximal hamstring avulsions may provide benefit in the context of research, while serial post-operative MRI will provide insight of what to expect in the clinical context of early re-injury requiring imaging. This study developed and assessed the reliability of a Proximal Hamstring Objective Magnetic Resonance Imaging Score (PHOMRIS), further assessing MRI-based repair status and its correlation with patient-reported outcome.Methods: 15 patients that underwent proximal hamstring surgical repair underwent MRI and clinical review preoperatively and at 3-, 6- and 12-months. Clinical scores included the Lower Extremity Functional Scale (LEFS), the Perth Hamstring Assessment Tool (PHAT) and Tegner Activity Scale (TAS). The MRI-based tool assessed the conjoint (semitendinosus & biceps femoris) and semimembranosus insertion components based on bone-tendon healing, signal and retraction. Inter- and intra-observer reliability of the tool was assessed. Results: Inter-observer reliability indicated a strong correlation for the semimembranosus (rho = 0.827, p < 0.0001) and conjoint (rho = 0.851, p < 0.0001) components. Intra-observer reliability indicated a strong correlation for the semimembranosus (rho = 0.852, p < 0.0001) and conjoint (rho = 0.996, p < 0.0001) components. All clinical scores and the semimembranosus hamstrings component MRI score significantly improved (p < 0.05) over time, though the conjoint component did not (p = 0.219). At 12 months, a higher LEFS was significantly associated with a better semimembranosus MRI score (r = -0.57, p = 0.042), though no other significant correlations (p > 0.05) were observed between clinical and MRI measures.Conclusions: Excellent reliability was observed for the MRI-based scoring tool, which may prove useful in both a research and clinical setting.