Risk factors of tear progression in symptomatic small to medium-sized full-thickness rotator cuff tear: relationship between occupation ratio of supraspinatus and work level.

Abstract

Previous studies reported that full-thickness rotator cuff tear (FTRCT) is a risk factor for tear progression. However, there is no clear consensus on the risk factors of tear progression in FTRCT. To identify the demographic and radiologic risk factors of tear progression in small to medium FTRCTs. We retrospectively reviewed 81 shoulders of patients diagnosed with small or medium FTRCTs using magnetic resonance imaging (MRI) who underwent conservative treatment from January 2017 to November 2021. Various demographic factors, including patient work level and radiological factors such as atrophy of rotator cuff muscles were analyzed to evaluate their association with tear progression. Work level was divided into high (heavy manual labor), medium (manual labor with less activity), and low (sedentary work activity). The atrophy of rotator cuff muscles was calculated by occupation ratio. Tear progression was observed in 48% (39/81) of patients (criterion for tear progression was medial-lateral or anterior-posterior tear length > 5 mm). In patients with tear progression, the lengths of medial-lateral and anterior-posterior tears progressed by 6 mm and 3 mm, respectively. Among the rotator cuff muscles, fatty degeneration and occupation ratio of the supraspinatus were only worsened (P=.014, P=0.013, respectively). The mean MRI follow-up duration was 14.8 ±9.0 months. The significant risk factors of tear progression were high work level (odds ratio [OR], 7.728; 95% CI, 1.204-49.610; P=.031), and occupation ratio of the supraspinatus muscle (OR, 0.308; 95% CI, 0.158-0.604; P=.001). The optimal cutoff value for the occupation ratio of the supraspinatus was 0.55 (sensitivity 74%, specificity 62%). Tear progression was observed in approximately 50% of patients with symptomatic small to medium FTRCTs. High physical work level and atrophy of the supraspinatus muscle were independent risk factors of tear progression. The risk of tear progression increases with occupation ratio of the supraspinatus muscle < 0.55 and heavy manual labor.