Excellent reliability for MRI grading and prognostic parameters in acute hamstring injuries.
The hamstring complex is the most frequently injured muscle during sporting activities. MRI is considered useful in verifying the diagnosis, severity – and therefore, the prognosis of hamstring injuries – all of which constitute valid predictors of time frames in returning to sport. Despite widespread application, no studies have investigated the reliability and smallest detectable differences (SDDs) in the MRI interpretation of hamstring injuries. The aim of this study was to determine the inter-rater and intra-rater reliability of MRI in the grading of acute hamstring injuries.
Two experienced radiologists evaluated 25 hamstring injuries via MRI. Prognostic parameters included: distance from the ischial tuberosity, extent, maximum cross-sectional area, and volume of oedema. Both the inter-rater and intra-rater reliability, along with the SDDs, were measured for each variable.
The MRI findings revealed 3 grade 0, 11 grade 1, 9 grade 2, and 2 grade 3 hamstring muscle injuries. Cronbach’s α values for grading were 1.00 (inter) and 0.96 (intra) respectively. The intraclass correlation coefficients for the prognostic MRI parameters were between 0.77 and 1.0.
The results of this study demonstrate excellent inter-rater and intra-rater reliability in assessing MRI grading, location, and extent of acute hamstring injuries. Furthermore, the SDDs allow clinically relevant inferences to be made when comparing within-subjects and between-subjects with muscle injuries to hamstring complex. > From: Hamilton et al., Br J Sports Med (2013) (Epub ahead of print). All rights reserved to BMJ Publishing Group Ltd.
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