A 19-Year-Old Woman with Increasing Shoulder Pain

The combination of clinical findings and MRI results was interpreted as a stress fracture. The patient began rehabilitation, with restriction from rowing activities for 6 weeks.

Reference: Knesek M, Walsh CP, Sabb B, Bedi A. Magnetic resonance imaging diagnosis of rib fracture in a competitive collegiate rower: a case report. JBJS Case Connect. 2012 Oct-Dec;2(4):e56.

Rib stress fractures account for a substantial amount of time lost from training and competition for rowers. Various studies have shown the rate of rib stress fractures in competitive rowers to range from 6.1% to 22.6%. There are numerous theories with regard to the mechanism and pathophysiology of rib stress fractures in these rowers. Multiple muscles acting on the ribs have been implicated because of considerable repetitive forces and possible muscle imbalances that may predispose to stress fractures. Analysis in cadavers has shown that the serratus anterior muscle can generate force that is sufficient enough to break ribs in the posterolateral region. Scapular retractors have been implicated as well, potentially because of force generated during the drive phase with leg extension. The abdominal oblique muscles have also clearly demonstrated deforming actions on ribs that could contribute to stress fractures.

A high clinical suspicion for rib stress fractures in elite rowers is very important because these injuries are relatively infrequently encountered in the general clinical setting. The history and physical examination remain important in the diagnosis, and several different imaging modalities can be used to confirm the clinical diagnosis. Conventional radiographs are often normal in the early setting of a stress reaction because abnormalities are only detected later, when periosteal or endosteal new bone formation is evident. Computed tomographic (CT) imaging is also poorly sensitive in the early stages of stress injuries; however, fracture lines may be identified. Radionuclide bone scanning is extremely sensitive for detecting osseous stress injuries, even in the early stages, by screening the entire skeleton. Positron emission tomography has also been used to diagnose the osseous stress reaction as it is another modality that screens for global metabolism. MRI is at least as sensitive as radionuclide scanning to detect osseous stress injuries by demonstrating marrow edema and periosteal fluid. MRI does offer certain advantages over other modalities such as radionuclide scanning, including shorter scan time, no ionizing radiation, improved specificity from the spatial resolution of the MRI, and simultaneous imaging of both bone and soft tissue. However, MRI is limited because it is not used for screening the entire skeleton. Thus, multiple imaging modalities allow the clinician to confirm or disprove stress fractures in competitive rowers. To the best of our knowledge, our case is one of the first reported uses of MRI to diagnose a stress fracture involving the rib of a competitive rower, and we believe that this modality holds promise for future early diagnoses of rib stress fractures.

Rib stress fractures in elite rowers can be a common cause of chest pain, back pain, or periscapular pain. However, there are multiple other causes of these symptoms, and diagnostic workup is necessary for a definitive diagnosis. Prompt recognition and diagnosis are important for correct therapy and rehabilitation. Various studies, including conventional radiographs, CT scans, radionuclide scans, and MRI, all have the ability to confirm stress fractures, although some are more sensitive than others. Although radionuclide scans remain the most commonly ordered study to confirm the diagnosis of rib stress fracture, MRI is a very good alternative that has multiple advantages over other imaging modalities. Our case highlights the ability of MRI to very clearly identify a stress fracture involving the eighth rib of a competitive rower.

Reference: Knesek M, Walsh CP, Sabb B, Bedi A. Magnetic resonance imaging diagnosis of rib fracture in a competitive collegiate rower: a case report. JBJS Case Connect. 2012 Oct-Dec;2(4):e56.