Background: Despite the essential role of vitamin D in muscle function, the prevalence of vitamin D deficiency has been reported
to be very high. Recently, low vitamin D level was found to correlate with fatty degeneration of the rotator cuff tendon in humans
and to negatively affect early healing at the rotator cuff repair site in an animal study. However, the effects of vitamin D level on
severity of rotator cuff tear and healing after surgical repair have not been documented.
Purpose: To evaluate (1) the prevalence of vitamin D deficiency among patients who underwent arthroscopic repair for a fullthickness
rotator cuff tear, (2) the relationship of vitamin D level with severity of the rotator cuff tear, and (3) surgical outcomes
after repair.
Study Design: Cohort study; Level of evidence, 2.
Methods: A consecutive series of 91 patients (age, 50-65 years) who underwent arthroscopic rotator cuff repair for full-thickness,
small-sized to massive tears were evaluated. Preoperative serum vitamin D levels (25-hydroxyvitamin) were analyzed to detect
correlations with the features of a preoperative rotator cuff tear as well as postoperative structural and functional outcomes.
All patients were followed clinically for a minimum of 1 year.
Results: Preoperative vitamin D levels were deficient (\20 ng/mL) in 80 subjects (88%), insufficient (20-30 ng/mL) in 8 subjects
(9%), and normal (.30 ng/mL) in 3 subjects (3%). No correlation was found between preoperative tear size (P = .23), extent of
retraction (P = .60), degree of fatty infiltration of each cuff muscle (P . .50 each), or the global fatty infiltration index (P = .32).
Similarly, no correlations were detected between vitamin D level and postoperative Sugaya type (P = .66) or any of the functional
outcome scores (P . .50 each).
Conclusion: Low serum vitamin D level was not related to tear size, extent of retraction, or the degree of fatty infiltration in cuff
muscles. It also had no significant relationships with postoperative structural integrity and functional outcomes after arthroscopic
repair. The results suggest that low serum vitamin D level is not a significant risk factor for the severity of rotator cuff tear or poor
healing after repair.