MRI appearance of myocutaneous flaps commonly used in orthopedic reconstructive surgery

Our aim was to describe the MRI appearance of myocutaneous flaps and to determine whether postoperative radiation therapy affects imaging.

We retrospectively reviewed 30 myocutaneous flaps in 27 patients (n = 165 examinations; mean, 6.1 examinations per patient). Examinations were analyzed for flap type, location, degree of atrophy, signal intensity, and enhancement.

Sixty-three percent (19/30) of the flaps developed high T1-weighted signal (mean, 15 months); 83% (25/30) developed high T2-weighted signal (mean, 10 months). This occurred sooner in those patients with postoperative radiation therapy (9 vs 12 months). T2-weighted signal returned to baseline in 32% (8/25) of the flaps (mean, 21 months); this occurred sooner in flaps not exposed to postoperative radiation (10 months vs 38 months). Seventy-one percent (20/28) of the flaps enhanced greater than the background musculature. Enhancement was seen more frequently in patients treated with postoperative radiation therapy than those not treated with radiation (83% vs 63%). All flaps atrophied; however, the two functional latissimus dorsi flaps atrophied less. Although increased T2-weighted signal and enhancement were seen in flaps after postoperative radiation therapy as compared with those without, this was not significant (p = 0.35 and p = 0.40, respectively).

Myocutaneous flaps used in orthopedic reconstructive surgery typically show increased signal intensity on T2-weighted images and contrast enhancement initially, followed by some degree of atrophy and increased signal intensity on T1-weighted images. Postoperative radiation therapy may increase the likelihood that the flap will exhibit increased T2-weighted signal and enhancement.