Dr. Kevin Yip

Dr Kevin Yip
Orthopaedic Surgeon
MBBS(UK), FRCS(EDIN), FAM(SING), FHKCOS(ORTHO)

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Pathoanatomy

Before describing the mechanics of rotator cuff pathology, post-mortem studies provide an interesting backdrop to the issue of etiology. There is little doubt that rotator cuff tearing is a function of age among other factors. Post-mortem studies have indicated an incidence of full or partial thickness tears ranging from 5% to nearly 40% . Fukuda et al. It reported a 13% incidence of partial rotator cuff tears in a cadaveric study of 249 anatomic specimens.

The prevalence of these partial thickness tears appears to increase with age. DePalma  studied 96 shoulders of patients aged 18 to 74 years without a history of shoulder dysfunction and found an incidence of partial ruptures of the supraspinatus tendon in 37%. Petersson  reported on 27 asymptomatic patients ranging from 55 to 85 years of age with a nearly 50% incidence of full or partial thickness tears based on arthrographic studies.

Suffice to say that tearing of the rotator cuff as a function of age is clearly a common occurrence. Furthermore, many of these tears, both full thickness and partial, may be clinically silent. As clinicians, we must be cautious in attributing causation to findings detected during diagnostic testing as these results may simply reflect the senescence process without significant clinical sequelae.

After a tear is noted, its natural history deserves attention. Several authors have reported on the progression of partial to full thickness tears. There is also evidence that full thickness tears are unable to heal spontaneously although an ineffective healing response may occur . Codman believed that spontaneous healing of partial tears might occur, yet histological studies of partial thickness rotator cuff tears has yielded no evidence of active repair.

Yamanaka  studied 40 patients with symptomatic articular-sided partial rotator cuff tears treated nonoperatively with serial arthrography. Repeat arthrography revealed that 10% of the tears had presumably healed, 10% had decreased in size while enlargement of tear size occurred in 51%, and 28% progressed to a full thickness tear.

A study comparing operative and nonoperative treatment for full-thickness rotator cuff tears concluded that larger rotator cuff tears in older individuals most likely progress in size although they can remain clinically quiescent. The study also concluded that the results of rotator cuff repair are clearly superior to that achieved with nonoperative measures only.

In a compelling longitudinal study of the natural course of rotator cuff tears, Yamaguchi et al.It reported on the risk of progression of asymptomatic rotator cuff tears detected by ultrasound in 58 patients with unilateral symptoms and bilateral rotator cuff tears. Fifty-one percent of asymptomatic tears became symptomatic over a three-year follow-up period. Nine of 23 patients restudied with ultrasound clearly demonstrated an increase in tear size, and no patient showed evidence of healing.

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