Rotator cuff degeneration of the healthy shoulder in patients with unilateral arm amputation is not worsened by overuse.

Purpose In order to evaluate whether overuse has a sig- nificant role in rotator cuff tear (RCT) aetiology, we evalu- ated both shoulders of patients with old unilateral arm amputation expecting a higher rate of RC degeneration in the healthy side.Methods Nineteen males and six females (mean age: 57.3 ± 10.1) with an old (>20 years) unilateral arm ampu- tation were submitted to an MRI of both shoulders. Ten- don status and muscle tropism were evaluated according to Sugaya and Fuchs classifications, respectively; the acro- mion humeral distance was measured. Statistical analy- sis was performed to verify the prevalence of Sugaya and Fuchs categories in each sides.Results A significant prevalence of Sugaya type II in the amputated side (p = 0.02) and of type I in the healthy side (p < 0.001) was found. Rotator cuff was healthy in 28 and 52% of amputated and non-amputated side, respectively. The mean acromio-humeral distances of the amputated and healthy side were 0.8 cm (SD: 0.1) and 0.9 cm (SD: 0.1), respectively, (p = 0.02). A significant prevalence of Fuchs type II category in the healthy side (p < 0.001) was found.