Assessing the accuracy of arthroscopic and open measurements of the size of rotator cuff tears: A simulation-based study.

Background: Arthroscopic procedures are commonly performed for rotator cuff pathology. Repair of rotator cuff tears is a commonly performed procedure. The intraoperative evaluation of the tear size and pattern contributes to the choice and completion of the technique and the prognosis of the repair.

Aim: To compare the arthroscopic and open measurements with the real dimensions of three different patterns of simulated rotator cuff tears of known size using a plastic shoulder model.

Methods: We created three sizes and patterns of simulated supraspinatus tears on a plastic shoulder model (small and large U-shaped, oval-shaped). Six orthopaedic surgeons with three levels of experience measured the dimensions of the tears arthroscopically, using a 5 mm probe, repeating the procedure three times, and then using a ruler (open technique). Arthroscopic, open and computerized measurements were compared.

Results: A constant underestimation of specific dimensions of the tears was found when measured with an arthroscope, compared to both the open and computerized measurements (mean differences up to -7.5 ± 5.8 mm, < 0.001). No differences were observed between the open and computerized measurements (mean difference -0.4 ± 1.6 mm). The accuracy of arthroscopic and open measurements was 90.5% and 98.5%, respectively. When comparing between levels of experience, senior residents reported smaller tear dimensions when compared both to staff surgeons and fellows.

Conclusion: This study suggests that arthroscopic measurements of full-thickness rotator cuff tears constantly underestimate the dimensions of the tears. Development of more precise arthroscopic techniques or tools for the evaluation of the size and type of rotator cuff tears are necessary.