The Use of an Intra-Articular Depth Guide in the Measurement of Partial Thickness Rotator Cuff Tears

Purpose. The purpose of this study was to compare the accuracy of the conventional method for determining the percentage of partial thickness rotator cuff tears to a method using an intra-articular depth guide. The clinical utility of the intra-articular depth guide was also examined. Methods. Partial rotator cuff tears were created in cadaveric shoulders. Exposed footprint, total tendon thickness, and percentage of tendon thickness torn were determined using both techniques. The results from the conventional and intra-articular depth guide methods were correlated with the true anatomic measurements. Thirty-two patients were evaluated in the clinical study. Results. Estimates of total tendon thickness (r = 0.41, P = 0.31) or percentage of thickness tears (r = 0.67, P = 0.07) using the conventional method did not correlate well with true tendon thickness. Using the intra-articular depth guide, estimates of exposed footprint (r = 0.92, P = 0.001), total tendon thickness (r = 0.96, P = 0.0001), and percentage of tendon thickness torn (r = 0.88, P = 0.004) correlated with true anatomic measurements. Seven of 32 patients had their treatment plan altered based on the measurements made by the intra-articular depth guide. Conclusions. The intra-articular depth guide appeared to better correlate with true anatomic measurements. It may be useful during the evaluation and development of treatment plans for partial thickness articular surface rotator cuff tears.