Manubrial stress fractures diagnosed on MRI: report of two cases and review of the literature

Abstract

In contrast to widely-reported sternal insufficiency fractures, stress fractures of the sternum from overuse are extremely rare. Of the 5 cases of sternal stress fracture published in the English-language medical literature, 3 were in the sternal body and only 2 were in the manubrium. We describe two cases of manubrial stress fracture related to golf and weightlifting, and present the first report of the MR findings of this injury. In each of these cases, the onset of pain was atraumatic, insidious, and associated with increased frequency of athletic activity. Imaging was obtained because of clinical diagnostic uncertainty. On MRI, each patient had a sagittally oriented stress fracture of the lateral manubrium adjacent to the first rib synchondrosis. Both patients had resolution of pain after a period of rest, with subsequent successful return to their respective activities. One patient had a follow-up MRI, which showed resolution of the manubrial marrow edema and fracture line. Based on the sternal anatomy and MR findings, we hypothesize that this rare injury might be caused by repetitive torque of the muscle forces on the first costal cartilage and manubrium, and propose that MRI might be an effective means of diagnosing manubrial stress fracture.

Bone Marrow Lesions in Athletic Stress Injuries: An Overview

“…But sternal stress-related injuries, such as those due to overuse in otherwise healthy patients, have rarely been reported, with only eight reported cases in the English-language medical literature: four in the sternal body and four in the manubrium. 32,33 Because upper body stresses are transmitted to the manubrium and sternum via the chest wall muscles, the ribs and costal cartilages, and the clavicles, sternal stress fractures may develop with repetitive activities involving these structures. Sternal stress fractures have been reported in a wrestler, a golfer, a sprinter performing strength workouts without technical supervision, and in (female) military recruits performing repetitive triceps dips during training.…”

“…But sternal stress-related injuries, such as those due to overuse in otherwise healthy patients, have rarely been reported, with only eight reported cases in the English-language medical literature: four in the sternal body and four in the manubrium. 32 33…”

“…On MRI, we may see a sagittal stress fracture of the lateral sternum adjacent to the rib synchondrosis or a transverse fracture. 33 Based on the sternal anatomy and MR findings, Baker and Demertzis 32 hypothesized that this rare stress injury might be caused by repetitive torque of the muscle forces on the costal cartilage and sternum, more often in the manubrium, and they propose that MRI might be an effective way to diagnose sternal stress fractures.…”

Sternal Stress Fractures

“…3,4 In doubtful cases, additional imaging tests, such as computed tomography and/or magnetic resonance imaging, can be useful in diagnosing this fracture, with several reports reporting a higher diagnostic sensitivity with these methods. 1,5,15 Although conventional radiographic study is generally considered to have a low sensitivity as a diagnostic method in stress fractures, lateral projection of the sternum can be very useful for the identification of the fracture, particularly when located in the sternal body as in our patients. Of interest is the potential applicability of ultrasound in the identification of this fracture.…”

Case Report: Surgical Management of Painful Manubriosternal Pseudoarthrosis

“…Motor vehicle crashes and chest seat belt restraints are the most common causes of sternal fracture. Reports of sternal injury among sportsmen and athletes are less common, however, with fracture resulting from non-contact trauma described in only sporadic cases in the literature (1)(2)(3)(4)(5).…”