Today's News

Thursday, March 16, 2000

AC joint pathology high in asymptomatic shoulders

A study of acromioclavicular (AC) joint pathology in asymptomatic shoulders using MRI, presented in scientific exhibit 317, found the incidence is high, especially in the over-30 age group, said Beth Shubin Stein, MD, fourth year resident, New York Orthopaedic Hospital of the Columbia Presbyterian Medical Center.

"Anterosuperior shoulder pain may result from AC joint arthrosis or impingement of the supraspinatus by a prominent AC joint capsule," Dr. Stein said. "MRI allows detection of subtle pathologic changes within the AC joint. Clinical symptoms, however, may not correlate with MRI findings thereby limiting its usefulness. The purpose of this study was to determine the prevalence of AC joint pathology in an asymptomatic population."

Fifty shoulders in 48 patients (22 male, 28 female) were evaluated with standard MRI techniques. The average age was 35 years old; range, 19-72 years. Patients were excluded if there was any history of shoulder trauma, infection, or arthritides. AC arthritis was graded on the amount of subacromial fat effacement, joint space narrowing and irregularity, capsular distension, and osteophyte formation on a scale of 1-4 (none, mild, moderate, and severe). Patients were divided into two groups: those under 30 years and over 30 years.

The researchers found 41 of 50 asymptomatic patients (82 percent) had evidence of arthritis. Seventy-one percent of those with arthritis were graded as mild; 21 percent, moderate; and 8 percent severe. In the under 30 age group, all AC changes were mild, whereas in the over 30 age group 71 percent of the AC findings were mild; 21 percent, moderate; and 8 percent severe. Significantly more advanced degenerative changes were found in the over 30 age group.

The researchers concluded that "clinical decisions, especially surgical intervention, should correlate the clinical exam with the MRI findings, as the false positive rate of AC joint abnormalities on MRI is significant."

Co-authors of the study, all of New York Orthopaedic Hospital at Columbia Presbyterian Medical Center, are J. Michael Wiater, MD, shoulder fellow; Charles Pfaff, MD, attending musculoskeletal radiologist; Louis U. Bigliani, MD, chairman of orthopaedic department; and William N. Levine, MD, chief, sports service, department of orthopaedics.

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2000 Academy News March 16 Index B

Last modified 06/March/2000 by IS