Competitive collegiate rowing has a long history, dating back to the nineteenth century. The oldest American intercollegiate athletic event on record is the Yale-Harvard boat race in 18521. While the mechanics of the sport remain largely unchanged, the extent of training and level of competition for collegiate rowers continue to increase. Competitive rowing is no longer a seasonal sport; these athletes are involved in year-round training, on ergometers (rowing machines) and in the water. This level of training, combined with the specific repetitive movements involved in rowing, makes elite rowers especially susceptible to injury.
The mechanics of the rowing motion can be analyzed in four phases: catch, drive, finish, and recovery. The catch phase is when the rower’s legs and back are fully flexed and the arms are extended as the oars enter the water. The drive phase is when the legs extend and the back slightly extends, followed by flexing of the arms to accelerate the oar through the water. The finish or release phase consists of the elbows drawing the blade through the water as well as movement of the handle down to remove the oar from the water. The recovery phase is when the oar is brought back to the starting position.
The timing and magnitude of these motions can lead to strain and overuse injuries2. It is therefore not surprising that back injuries are very common among rowers. The differential diagnosis for back pain in a rower includes muscle strain, ligament and/or tendon injury, tear of the anulus fibrosus, or stress fractures. Although stress fractures of the ribs are rare in the general population, they have a relatively high frequency (6.1% to 22.6%) in competitive rowers3,4.
While stress fractures have been long identified as a consequence of vigorous athletic training, the majority of sports-related stress fractures are seen in the lower extremities, including the tibia, metatarsals, and femur. The predominant activities that most commonly contribute to stress fractures include long-distance running, athletics and ball games of various kinds, and ballet dancing. Stress fractures of the ribs have been diagnosed in baseball pitchers, golfers, canoers, and rowers5-10. The most common location described in various case reports involves the anterolateral to posterolateral aspect of ribs five to nine11. Almost all case reports of rib fractures document diagnoses based on imaging modalities, most commonly technetium-99 bone scans, although computed tomography (CT) scans and radiographs have also been reported to be useful. Magnetic resonance imaging (MRI) presents a new modality for the diagnosis of stress fractures. In this report, we present a case involving a rib fracture in a rower, which, to the best of our knowledge, is among the first described in the literature to have been diagnosed with MRI. The patient was informed that data concerning the case would be submitted for publication, and she provided consent.
A nineteen-year-old, right-hand-dominant female rower presented to the clinic with left periscapular pain. She had previously experienced right-sided pain of a similar nature when she had been a port-side rower. When she had switched to become a starboard-side rower, the right-sided pain gradually subsided, but over the next year she had developed left-sided pain. She described the pain as starting at the beginning of the finish phase, as well as with full extension and scapular protraction. She noticed this pain most often when she was training on the ergometer. The pain had progressed to the point where she had pain at rest and during sleep, as well as pain in the periscapular region while taking a deep breath. She reported the sensation of having a “knot” in the muscles surrounding the inferior aspect of the left scapula. There was no reported mechanism for an acute injury. There was no history of scoliosis or other back problems. Examination demonstrated neck and shoulder motion within normal limits. There was tenderness over the inferior aspect of the left scapula as well as the lateral chest wall, over the serratus anterior muscle. There was mild restriction in left-sided shoulder internal and external rotation (T5 versus T3) compared with the right shoulder. There was mild winging of the left scapula noted on observation of a wall push-up.
Given the clinical history and physical examination, there was very high concern for a stress fracture. At the initial visit, radiographs of the left shoulder demonstrated no abnormalities. As a result, an MRI of the left shoulder and rib cage was ordered to rule out any stress fractures of the ribs. In the meantime, the patient began physical therapy, avoiding any ergometer training or rowing activity. On completion of the MRI and additional review of the chest radiographs, a stress fracture was confirmed. The chest radiograph demonstrated cortical discontinuity along the posterolateral aspect of the eighth rib, and the MRI demonstrated increased marrow signal along the posterior level of the eighth rib. The difference between normal and abnormal marrow was clearly seen in axial short tau inversion recovery (STIR) images (Figs. 1-A and 1-B). Sagittal images demonstrated increased signal intensity in the eighth rib compared with the other ribs (Fig. 2). After the diagnosis of rib stress fracture was confirmed, the patient began rehabilitation, with restriction from rowing activities for six weeks.
Rib stress fractures account for a substantial amount of time lost from training and competition for rowers. Various studies report the rate of rib stress fractures in competitive rowers to range from 6.1% to 22.6%3,4. There are numerous theories regarding 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 region12. Scapular retractors have been implicated as well, potentially because of force generated during the drive phase with leg extension4. The abdominal oblique muscles have also clearly demonstrated deforming actions on ribs that could contribute to stress fractures10.
A high clinical suspicion for rib stress fractures in elite rowers is very important since 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 since abnormalities are only detected later, when periosteal or endosteal new bone formation is evident13. 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 skeleton14. Positron emission tomography has also been used to diagnose osseous stress reaction since it is another modality that screens for global metabolism15. MRI is at least as sensitive as radionuclide scanning to detect osseous stress injuries by demonstrating marrow edema and periosteal fluid16. 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 skeleton13. 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. There are, however, multiple other causes of these symptoms, and diagnostic workup is necessary for a definitive diagnosis. Prompt recognition and diagnosis is 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.
Boland
AL;
Hosea
TM. Rowing and sculling and the older athlete. Clin Sports Med.
1991;10(
2):245-56.[PubMed]
Vinther
A;
Alkjaer
R;
Kanstrup
I-L;
Zerahn
B;
Ekdahl
C;
Jensen
K;
Holsgaard-Larsen
A;
Aagaard
P. Neuromuscular activity and force production during slide-based and stationary ergometer rowing. Br J Sports Med.
2011;45(
4):381-2.[CrossRef]
Hickey
GJ;
Fricker
PA;
McDonald
WA. Injuries to elite rowers over a 10-yr period. Med Sci Sports Exerc.
1997;29(
12):1567-72.[PubMed][CrossRef]
Warden
SJ;
Gutschlag
FR;
Wajswelner
H;
Crossley
KM. Aetiology of rib stress fractures in rowers. Sports Med.
2002;32(
13):819-36.[PubMed][CrossRef]
Gurtler
R;
Pavlov
H;
Torg
JS. Stress fracture of the ipsilateral first rib in a pitcher. Am J Sports Med.
1985;13(
4):277-9.[PubMed][CrossRef]
Holden
DL;
Jackson
DW. Stress fracture of the ribs in female rowers. Am J Sports Med.
1985;13(
5):342-8.[PubMed][CrossRef]
Lord
MJ;
Ha
KI;
Song
KS. Stress fractures of the ribs in golfers. Am J Sports Med.
1996;24(
1):118-22.[PubMed][CrossRef]
Maffulli
N;
Pintore
E. Stress fracture of the sixth rib in a canoeist. Br J Sports Med.
1990;24(
4):247.[PubMed][CrossRef]
McKenzie
DC. Stress fracture of the rib in an elite oarsman. Int J Sports Med.
1989;10(
3):220-2.[PubMed][CrossRef]
Mier
A;
Brophy
C;
Estenne
M;
Moxham
J;
Green
M;
De Troyer
A. Action of abdominal muscles on rib cage in humans. J Appl Physiol.
1985;58(
5):1438-43.[PubMed]
Karlson
KA. Rib stress fractures in elite rowers. A case series and proposed mechanism. Am J Sports Med.
1998;26(
4):516-9.[PubMed]
Satou
S;
Konisi
N. [The mechanism of fatigue fracture of the ribs]. Nihon Seikeigeka Gakkai Zasshi.
1991;65(
9):708-19. .[PubMed]
Anderson
MW. Imaging of upper extremity stress fractures in the athlete. Clin Sports Med.
2006;25(
3):489-504, .[PubMed][CrossRef]
Ammann
W;
Matheson
GO. Radionuclide bone imaging in the detection of stress fractures. Clin J Sports Med.
1991;1(
2):115-22.[CrossRef]
Slipman
CW;
Patel
RK;
Vresilovic
EJ;
Brautigam
P;
Mathies
A;
Adam
LE;
Lenrow
D;
Bhat
AL;
Isaac
Z;
Alavi
A. Osseous stress reaction in a rower diagnosed with positron emission tomography (PET): a case report. Pain Physician.
2001;4(
4):336-42.[PubMed]
Anderson
MW;
Greenspan
A. Stress fractures. Radiology.
1996;199(
1):1-12.[PubMed]
Disclosure: None of the authors received payments or services, either directly or indirectly (i.e., via his or her institution), from a third party in support of any aspect of this work. One or more of the authors, or his or her institution, has had a financial relationship, in the thirty-six months prior to submission of this work, with an entity in the biomedical arena that could be perceived to influence or have the potential to influence what is written in this work. No author has had any other relationships, or has engaged in any other activities, that could be perceived to influence or have the potential to influence what is written in this work. The complete Disclosures of Potential Conflicts of Interest submitted by authors are always provided with the online version of the article.