The natural course of and risk factors for tear progression in conservatively treated full-thickness rotator cuff tears.

BACKGROUND

The natural course of and risk factors for tear progression in full-thickness rotator cuff tears (FTRCTs) have not been clarified yet. The study's purpose was to retrospectively evaluate tear progression in FTRCTs by using magnetic resonance imaging (MRI) and to identify risk factors that are relevant to such tear progression.

METHODS

Between June 2010 and September 2019, a total of 345 patients with FTRCTs who had been diagnosed via MRI were treated conservatively. Of these, 48 patients who underwent post-treatment follow-up MRI were retrospectively enrolled. Tear progression was defined as significant when the tear size increased by >5 mm.

RESULTS

The mean MRI follow-up duration was 22 ± 14 months (range, 12-65 months). Among the 48 patients (mean age, 69 years; range, 53-81), 26 (54%) and 20 (41%) showed medial-lateral (M-L) and anterior-posterior (A-P) tear progression on MRI follow-up. Multivariate analysis revealed that MRI follow-up duration (P = .011), diabetes mellitus (P = .017), and infraspinatus muscle atrophy (P = .011) were independent risk factors for tear progression in the A-P plane. A high critical shoulder angle (P = .011) and supraspinatus (P = .024) and infraspinatus (P = .020) muscle atrophy were risk factors associated with M-L tear progression.

CONCLUSION

Among the assessed patients, a considerable number of FTRCTs increased in size during the follow-up period. Severe infraspinatus muscle atrophy was the independent risk factor for exacerbation of A-P and M-L tear progression.