SEMIMEMBRANOSUS-TIBAL COLLATERAL LIGAMENT BURSITIS - MR-IMAGING FINDINGS

PURPOSE. The purpose of this paper is to describe the MR imaging chara cteristics of semimembranosus-tibial collateral ligament (SMTCL) bursi tis. MATERIALS AND METHODS. Fifteen patients (37-68 years old) with me dial joint pain and presumed internal derangements of the knee underwe nt MR imaging. Fluid collections around the SMTCL were found prospecti vely in five patients. Our retrospective evaluation of recent MR imagi ng cases that had been previously diagnosed as pes anserinus bursitis revealed 10 additional cases with similar findings. RESULTS. We believ e that SMTCL bursitis clinically explained the patients' medial pain i n all cases diagnosed prospectively. We gave the additional cases the same diagnosis presumptively. CONCLUSIONS. SMTCL bursitis has a charac teristic MR imaging appearance of fluid draped over the semimembranosu s tendon in the shape of an inverted U. This entity can clinically mim ic internal derangement of the knee, typically causing pain more super ior and posterior to that of pea anserinus bursitis. MR imaging is use ful in diagnosing SMTCL bursitis and avoiding unnecessary knee arthros copy.