Friday, October 30, 2009

Weightlifting and the Distal Clavicle

Photo by greg westfall

Weightlifting is an ancient sport, dating back to ancient China, Egypt, and Greece. I'm sure that even before these recorded competitions, there were plenty of contests of brute strength, including lifting heavy rocks:

The original Olympics did not include weightlifting as an event, but it was still a popular pastime in ancient Greece. Weightlifting continues to this day, and one popular exercise is the bench press:

Photo by Justin Berndt

This exercise places a great deal of strain on the glenohumeral (shoulder) joint and the adjacent acromioclavicular (AC) joint. One consequence of repeated increase strain on the AC joint can be osteolysis of the distal clavicle.

In this case a 36 year-old female felt the gradual increase of shoulder pain while increasing the number of pushups she was doing daily. She then experienced an abrupt increase in her pain after moving luggage from overhead compartment in a plane. Her orthopedic surgeon sent her for an MRI:

Sagittal T2 fatsat image reveals striking bone marrow edema (yellow arrow) within the distal clavicle.

On an axial T2 fatsat image, there is a linear, hypointense fracture line (yellow arrows) within the subchondral bone:

A coronal intermediate-weighted image confirms the presence of the subchondral fracture:

Repetitive stress can lead to bone marrow edema and a subchondral fracture line within the distal clavicle. Demineralization and bone resorption may follow. (Textbook of Arthroscopy; Miller, M. and Cole, B.; 178-179, 2004 and Kassarjian et al.; Skel. Rad. 36:17-22, 2007)

On physical examination, patients have point tenderness over the affected AC joint. The range of motion of the glenohumeral joint is typically not affected.

Thus, a subchondral stress fracture may be the earliest MRI manifestation of distal clavicular osteolysis.

Vic David MD

Saturday, October 3, 2009

Horse Racing and Foreign Bodies

Photo by raymond

Horse racing is an ancient sport. Its origins date back to about 4500 B.C, among the nomadic tribesmen of Central Asia (who first domesticated the horse). The sport has a history of nobility, but interest in the sport can be found at all rungs of the societal ladder. In the modern world, organized horse racing is done at a racetrack. Many horse racing tracks are quite old, and are constructed mostly of wood.

In this case, a 71 year old woman went to a race track four weeks ago, and felt a sharp pain as she ran her hand along a wooden railing. Her clinician suspected a wooden splinter, but was unable to detect one on clinical examination. She was sent for an MRI:

Sagittal T2 fat sat image reveals a linear structure (red arrow) surrounded by fluid.

Axial and coronal T2 fatsat images confirm the presence of a wooden splinter:

What is the best test for a foreign body? While MRI can reveal foreign bodies, it is not very sensitive for the presence of non-metallic foreign bodies. Thus, despite what we see in this case, if the clinical question is "rule out foreign body", one should generally start with an x-ray. If this is negative, one can go on to CT or ultrasound, with the choice depending many times on local clinical practice.

Remember— while MRI can detect foreign bodies, it is not the ideal test, particularly if the foreign body is non-metallic in nature.

Vic David MD