The effects of disease progression and common tendinopathy treatments
on the tissue characteristics of human rotator cuff tendons have
not previously been evaluated in detail owing to a lack of suitable
sampling techniques. This study evaluated the structural characteristics
of torn human supraspinatus tendons across the full disease spectrum,
and the short-term effects of subacromial corticosteroid injections
(SCIs) and subacromial decompression (SAD) surgery on these structural
characteristics. Samples were collected inter-operatively from supraspinatus tendons
containing small, medium, large and massive full thickness tears
(n = 33). Using a novel minimally invasive biopsy technique, paired
samples were also collected from supraspinatus tendons containing
partial thickness tears either before and seven weeks after subacromial
SCI (n = 11), or before and seven weeks after SAD surgery (n = 14).
Macroscopically normal subscapularis tendons of older patients (n
= 5, mean age = 74.6 years) and supraspinatus tendons of younger
patients (n = 16, mean age = 23.3) served as controls. Ultra- and
micro-structural characteristics were assessed using atomic force
microscopy and polarised light microscopy respectively. Objectives
Methods
We assessed the predictive value of the macroscopic and detailed microscopic appearance of the coracoacromial ligament, subacromial bursa and rotator-cuff tendon in 20 patients undergoing subacromial decompression for impingement in the absence of full-thickness tears of the rotator cuff. Histologically, all specimens had features of degenerative change and oedema in the extracellular matrix. Inflammatory cells were seen, but there was no evidence of chronic inflammation. However, the outcome was not related to cell counts. At three months the mean Oxford shoulder score had improved from 29.2 (20 to 40) to 39.4 (28 to 48) (p <
0.0001) and at six months to 45.5 (36 to 48) (p <
0.0001). At six months, although all patients had improved, the seven patients with a hooked acromion had done so to a less extent than those with a flat or curved acromion judged by their mean Oxford shoulder scores of 43.5 and 46.5 respectively (p = 0.046). All five patients with partial-thickness tears were within this group and demonstrated less improvement than the patients with no tear (mean Oxford shoulder scores 43.2 and 46.4, respectively, p = 0.04). These findings imply that in the presence of a partial-thickness tear subacromial decompression may require additional specific treatment to the rotator cuff if the outcome is to be improved further.
