Inter and intraobserver variability in DePalma's classification of shoulder calcific tendinitis

To determine the intraobserver reproducibility and interobserver reliability of DePalma and Kruper's classification of calcific tendinitis of the rotator cuff. The result of this classification influences the choice of therapeutic procedures in patients with symptomatic calcific tendinitis.

Plain anteroposterior radiographs of shoulders from 100 patients with symptomatic calcified deposits of the rotator cuff were classified according to the criteria of DePalma and Kruper by 6 independent observers at 2 different time points within 4 months. The kappa values of intraobserver reproducibility and interobserver reliability were calculated.

Kappa values of intraobserver reproducibility had a mean of 0.487 (SD 0.094); kappa values of interobserver reliability were 0.234 for the first test and 0.273 for the second test.

Determination of intraobserver reproducibility gave satisfactory to sufficient results and interobserver reliability was satisfactory for both tests indicating that studies based on the classification of DePalma and Kruper should be interpreted cautiously.