Imaging of acute lower limb muscle injury and potential gender differences.

OBJECTIVES

To assess the most common lower limb acute muscle injuries on MRI imaging in a national specialist centre for orthopaedics and sports medicine and to explore potential gender differences.

METHODS

Over a 3-year time period, all MRI lower limb studies with acute muscle injury (AMI) were reviewed. A British Athletics muscle injury classification (BAMIC) was given and a statistical analysis was performed.

RESULTS

A total of 195 AMIs were diagnosed: 177 (91%) male and 18 (9%) female injuries (M to F = 9.8:1). The most common lower limb AMIs were BAMIC grade 1a injuries (n = 48, 25%). The most commonly injured muscle was biceps femoris (n = 87, 45%), specifically grade 1b and grade 2b injuries. There was no significant difference in age between men and women with acute lower limb muscle injuries (p = 0.19). Females were 1.5 times more likely to have a lower grade AMI than males, although this did not reach statistical significance (p = 0.7) owing to a striking lower number of female patients. There was no significant difference between genders in the likelihood of sustaining a hamstring or quadricep AMI (hamstrings OR = 2.47, p = 0.14 and quadriceps OR = 0.926, p 0.99).

CONCLUSIONS

Grade 1a is the most common lower limb AMI grade in our institution, accounting for 25%. Biceps femoris is the most commonly injured muscle (45%) with grade 1b and grade 2b being the most frequently encountered grades of biceps femoris injuries. Lower-grade injuries are more common in females compared to males, although not significantly so. Further studies are required to explore possible reasons for this gender gap.