Inter and Intraobserver Variability in DePalma's Classification of Shoulder Calcific Tendinitis

MARKUS MAIER, TAMARA MAIER-BOSSE, CHRISTOPH U. SCHULZ, MARC STEINBORN, CLEMENS A. SCHMITT, MARTIN KLEEN, and AXEL STÄBLER

ABSTRACT.

Objective. 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.

Methods. 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.

Results. 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.

Conclusion. 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. (J Rheumatol 2003;30:1029-31)

Key Indexing Terms:

CALCIFIC TENDINITIS
SHOULDER
KAPPA STATISTICS
MORPHOLOGY
CLASSIFICATION
DEPALMA AND KRUPER

---

From the Department of Orthopedic Surgery, the Institute of Surgical Research, the Institute of Clinical Radiology, and the Institute of Anesthesia, Ludwig-Maximilians-University Munich, Klinikum Grosshadern, Munich; and the Max-Delbrueck-Center for Molecular Medicine, Charité/Campus Virchow-Klinikum, Berlin, Germany.

M. Maier, MD, Consultant Orthopedic Surgery, Institute of Surgical Research and Institute of Clinical Radiology; T. Maier-Bosse, MD, Registrar Orthopedic Surgery; C.U. Schulz, MD, Senior Consultant Orthopedic Surgery, Department of Orthopedic Surgery; M. Steinborn, MD, Registrar Radiology, Institute of Clinical Radiology; M. Kleen, MD, Assistant Professor Anesthesiology, Institute of Surgical Research and the Institute of Anesthesia; A. Stäbler, MD, Assistant Professor Radiology, Institute of Clinical Radiology, Ludwig-Maximilians-University Munich; C.A. Schmitt, Academic Clinician and Principal Investigator, Max-Delbrueck-Center for Molecular Medicine, Charité/Campus Virchow-Klinikum.

Address reprint requests to Dr. M. Maier, Department of Orthopedic Surgery, Ludwig-Maximilians University Munich, Klinikum Grosshadern, Marchioninistr. 15, D-81377 Munich, Germany. E-mail: markus.maier@ort.med.uni-muenchen.de

Submitted April 9, 2002; revision accepted October 14, 2002.

---