Changes in tendon length with increasing rotator cuff tear size.

PURPOSE: To investigate the change in tendon length with increasing size of rotator cuff tears in patients receiving arthroscopic rotator cuff repair.
METHODS: This is a prospective evaluation of 100 consecutive patients who met the inclusion criterion of a U-shaped or crescent-shaped full-thickness tear and who were treated by arthroscopic rotator cuff (supraspinatus and/or infraspinatus) repair from 2009 to 2010. The anterior-to-posterior dimension of the cuff tear was estimated under arthroscopic guidance, and the medial-to-lateral dimension was estimated on pre-operative MRI. The tendon length, from its distal end to the musculotendinous junction, was estimated under arthroscopic observation after arthroscopic rotator cuff repair. The relationships between tendon length and the anterior-to-posterior and medial-to-lateral dimensions of the cuff tear were analyzed.
RESULTS: The average tendon length in patients with full-thickness tears was 17.0 mm. The tendon length decreased significantly with an increase in cuff tear size, for both the anterior-to-posterior (r = -0.328, P = 0.001) and medial-to-lateral dimensions (r = -0.681, P < 0.001). When the full-thickness tears were grouped according to the lengths of the anterior-to-posterior and medial-to-lateral dimensions, tendon length differed significantly among the groups (P = 0.008 and P < 0.001, respectively).
CONCLUSIONS: In full-thickness tears, the rotator cuff tendon length decreased with increases in the anterior-to-posterior and medial-to-lateral dimensions of the tear size, with a higher correlation between tendon length and the medial-to-lateral dimension. During arthroscopic rotator cuff repair, passing a suture too medially for complete footprint coverage using a strong fixation technique can lead to excess tension and medial cuff tears. LEVEL OF EVIDENCE: II.