Determining the rate of full-thickness progression in partial-thickness rotator cuff tears: a systematic review

Partial-thickness rotator cuff tears are likely at least as common as full-thickness rotator cuff tears, and it is critical for surgeons to have knowledge of the tear progression rate of partial-thickness rotator cuff tears when determining surgical or nonsurgical treatment. However, a systematic review investigating the rate of tear progression of partial-thickness rotator cuff tears has not been performed. Therefore, the purpose of this study was to systematically review the literature and determine the rate of full-thickness progression in nonoperatively treated partial-thickness rotator cuff tears.

A systematic review of the literature was performed following the PRISMA guidelines and checklist using the PubMed, MEDLINE, and Cochrane Library databases. English-language studies of Level I through IV evidence examining partial-thickness rotator cuff tears with description of the change in tear size were included. Studies using imaging modalities other than magnetic resonance imaging (MRI) or ultrasonography (US) for serial imaging and studies without description of the number of tears that progressed to full-thickness tears were excluded. The primary outcome was to determine the per-month progression rate from a partial-thickness tear to a full-thickness tear confirmed on either MRI or US. The progression rates, which were divided into 3 groups-symptomatic, asymptomatic and combined (asymptomatic + symptomatic)-were calculated using a random effects model with binomial within-study variance.

Four studies were included, and 257 tears were analyzed statistically for tear progression. The average follow-up was 34 months (standard deviation, 19 months). The overall rate of progression to a full-thickness tear was 0.26% per month (95% confidence interval [CI], 0.15%-0.36% per month). In the symptomatic and asymptomatic groups, the rates were 0.22% per month (95% CI, 0.09%-0.34% per month) and 0.32% per month (95% CI, 0.15%-0.49% per month), respectively, which showed no significant difference (P =.341).

This study demonstrated that partial-thickness tears progress to full-thickness tears over time but at a relatively low rate at short- to intermediate-term follow-up. There was no significant difference in the per-month rates of full-thickness progression between symptomatic and asymptomatic tears.