Functional Outcome After Repair of Proximal Hamstring Avulsions

Background: Rupture of the proximal origin of the hamstrings leads to pain, weakness, and a debilitating decrease in physical activity. Repair of these injuries should be based on the expectation that these deficits can be addressed. The goal of this study was to objectively evaluate the efficacy of repair of proximal hamstring avulsions. Methods: Thirty-four patients were identified retrospectively to have a complete rupture of the proximal origin of the hamstrings based on the presence of a bowstring sign and the results of magnetic resonance imaging (MRI). Patients were contacted for follow-up evaluation to fill out a subjective questionnaire, to undergo functional testing, and to undergo isokinetic testing on a Cybex dynamometer. Twenty-three patients were evaluated. Results: There were nine acute and fourteen chronic repairs, and the average period of follow-up was 43.3 months. Twenty-one of twenty-three patients reported returning to activity at an average of 95% of their pre-injury activity level at an average of 9.8 months: Eighteen patients reported excellent results; four, good results; and one, fair results. Hamstring strength was an average of 93% and 90% of that in the uninvolved limb at 240 degrees per second and 180 degrees per second, respectively. The hamstrings-to-quadriceps ratio was 56% for 240 per second and 48% at 180 degrees per second. Hamstring endurance was an average of 81% and 91% of the nonoperative limb at 240 degrees per second and 180 degrees per second, respectively. Postoperative quadriceps strength and endurance were positively correlated with return to pre-injury level of activity (r = 0.6, p < 0.05; and r = 0.6, p < 0.05) and negatively correlated with time to return to sport (r = -0.5, p < 0.05; and r = -0.5, p < 0.05). There was no significant effect associated with age or time from injury. Conclusions: Repair of a symptomatic and displaced ruptured proximal hamstring tendon yields good subjective and objective functional results with minimal complications. Overall, patients are satisfied with surgical repair and experience return of functional activity with minimal postoperative weakness.