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Arthroscopy may not accurately estimate glenoid bone loss in patients with shoulder instability
Investigators of this study found glenoid bone loss in patients with recurrent anterior shoulder instability is severely overestimated with the use of arthroscopy compared with 3-D CT scans.
Researchers retrospectively reviewed information for 22 patients (with a mean age of 25.4 years) who had recurrent anterior shoulder instability and glenoid bone loss, and underwent preoperative bilateral shoulder CT scans. Using the bare-spot method, researchers arthroscopically estimated glenoid bone loss. They also created 3-D CT reconstructions using patients’ CT scans. In addition, investigators measured glenoid bone loss using the surface area, Pico, ratio and anteroposterior (AP) distance-from-bare area methods. The reliability of arthroscopy to measure glenoid bone loss was determined using the mean percent loss from each method compared with the percent bone loss estimated at the time of arthroscopy.
Findings showed the glenoid bony defect was 5% to 40% when measured arthroscopically. The mean percent bone loss was 18.13%, 12.15%, 12.77%, 9.50% and 12.44% when measured with the arthroscopic estimation, surface area, Pico, ratio and AP distance-from-bare area methods, respectively. Investigators found the estimation of bone loss made with arthroscopy was 55% greater than that using the average of the 3D-CT methods.
“Our findings suggest that arthroscopy significantly overestimates glenoid bone loss compared with CT and call into question its validity as a method of measurement,” the researchers wrote. “A more internally consistent and accurate method for the measurement of glenoid bone loss is necessary to appropriately diagnose and treat shoulder instability.” ‒ by Monica Jaramillo
Disclosures: The researchers reported funding from the Michigan Institute for Clinical Health and Research, University of Michigan, Intramural Grant. Please see the full study for a list of all other authors’ financial disclosures.