MRI scans predict muscle loss in hamstring injuries treated without surgery
A new study shows that the initial position of a torn hamstring tendon on MRI scans can forecast whether a patient will experience significant muscle deterioration months later, even with conservative treatment. The finding could help clinicians decide which patients need surgery versus rest, potentially saving costs and improving recovery outcomes.
Originaltitel: Initial Tendon Retraction is Associated with Muscle Degeneration After Nonoperatively Treated Proximal Hamstring Avulsions
<p>Background and PurposeMagnetic resonance imaging (MRI) is essential in assessing proximal hamstring avulsions (PHA), where tendon retraction is a key pathological consequence. Beyond its diagnostic role, MRI may also provide prognostic information on subsequent muscle degeneration. This study aimed to determine whether pre-treatment MRI findings, particularly tendon retraction, predict later muscle degeneration and clinical outcomes in nonoperatively treated PHA patients.MethodsThis study is a post hoc analysis of nonoperatively treated patients (n = 95) with complete proximal hamstring avulsions from the Proximal Hamstring Avulsion Clinical Trial (PHACT). Diagnostic MRIs were reassessed for tendon retraction, Wood classification, number of tendons avulsed, and hematoma size. The primary outcome was muscle degeneration, defined by the loss of lean muscle volume (LMV) and an increase in muscle fat fraction (MFF) quantified by DIXON MRI at 24 months. The secondary outcome was maximum hamstring muscle isometric force at 24 months. Outcome data was expressed as the limb symmetry index (LSI), which was the measurement of the injured hamstring expressed as a percentage of measurement of the uninjured hamstring. Linear regression was used to analyze the association between diagnostic MRI measurements, patient factors, and LSIs for LMV, MFF, and maximum isometric force.ResultsThe median (IQR) LSIs of the LMV, MFF and maximum strength were 78% (67.2, 87.1), 139% (124.5, 166.8), and 84% (75.4, 94.0), respectively, at 24-month follow-up. A multivariate linear regression model including tendon retraction, age, sex, hematoma size and whether the dominant limb was injured explained 48%, 48% and 23% of the variance in the LSIs of LMV, MFF and maximum force, respectively. Tendon retraction was the strongest explanatory factor for the variance of muscle degeneration observed in patients with nonoperatively treated PHA.InterpretationGreater initial tendon retraction is associated with increased muscle atrophy and fat infiltration in the hamstring muscles in patients with nonoperatively treated PHA.Trial registration: NCT03311997.InterpretationGreater initial tendon retraction is associated with increased muscle atrophy and fat infiltration in the hamstring muscles in patients with nonoperatively treated PHA.Trial registration: NCT03311997.</p>