Is There a Gender Difference in Fat Distribution around the Hamstring Tendon Insertion? A Prospective MRI Evaluation of 40 Cases

Abstract

Introduction. Knee ligament reconstructions are commonly performed using hamstring tendon grafts. We observed anecdotally that there was a difference in the fat distribution superficial to the pes anserinus between men and women and proposed that this effect was independent of BMI, being significantly greater in women. Methods. We performed a prospective study to evaluate 40 MRI scans performed in 20 women and 20 men. The scans allowed visualisation of the insertion of the hamstring tendons at the pes anserinus. Results. The mean BMI of the male patients was 25.6 (19.8–37.2) and of the female patients was 24.7 (17.9–34.5). The mean fat distribution superficial to the pes anserinus in men was 16.2 mm (4.1–29.4) and in women was 29.7 mm (19.6–47.5). There was a significant increase in fat superficial to the hamstring tendons in women compared with men (P<0.001), despite no significant difference in BMI (P=0.5). Conclusions. Our evaluation of a prospective series of MRI scans has shown that there is significantly more fat superficial to the insertion of the hamstring tendons in women than in men. This effect is independent of BMI and may influence exposure during hamstring tendon graft harvesting.