Purpose: Reports on the histological lesions observed in patients with degenerative disease of the shoulder have generally involved only a few cases. We conducted a prospective study in 662 shoulders operated on for impingement or rotator cuff tear.
Material: The cases analysed included 402 subacromial impingements and 260 rotator cuff tears.
Methods: Pathology specimens were obtained from the subacromiodeltoid bursa, the acromion, the acromio-coracoid ligament, the acromioclavicular joint, the borders of the rotator cuff tear, and the biceps tendon. There were 2573 pathology specimens.
Results: The pathology examination revealed degenerative lesions (fibrosis, oedema, calcifications, fissuration, atrophy, delamination, fatty infiltration, necrosis, chondroid metaplasia, fragmentation), or inflammation. The subacromiodeltoid bursa presented fibrosis lesions in 3 out of 4 cases (74%). Signs of inflammation were found in 21% of the cases, oedema in 9%, and no lesion in 15%. The acromiocoracoid ligament showed oedema in 35%, fissuration in 35%, delamination in 25%, fragmentation in 11%, atrophy in 8%, fatty infiltration in 6%, necrosis in 4%, hypervascularisation in 2%, chondroid metaplasia in 1%, and no lesion in 27%. For the acromion, degenerative lesions were present in 88%, impingement in 83%, cuff tears in 92%. Lesions of the cuff in patients with tears showed degeneration in 86% (fissuration 46%, necrosis 35%, fragmentation 30%, vascular penetration with chondroid metaplasia 17%, delamination 10%, haemorrhagic remodelling 4%, adipose degeneration 3%, atrophy 2%, oedema 42%, calcifications 30%, fibrosis 26%, inflammation 7%, and no lesion 1 case). The biceps tendon showed degenerative lesions (90%), inflammation 2 cases, no lesion 3 cases. The acromioclavian joint (67 cases) showed degenerative lesions in all cases. Rotator cuff tears showed inflammatory lesions 30%, and subacromial impingement 16%.
Discussion: The statistical analysis revealed a significant correlation between the presence of a normal subacromiodeltoid bursa and the type of pathology. There was a significant statistical relationship between the presence of inflammatory lesions and the type of pathology. There was no significant correlation with the pain score. There was a significant relationship between the presence of fibrosis of the acromiocoracoid ligament and the functional score at last follow-up. The presence of ligament fibrosis would be a sign of poor prognosis. This relationship was present irrespective of the pain, force and stability scores.
Conclusion: The acromiocoracoid ligament was not found to be particularly involved suggesting that the idea of impingement should be revisited. For cases with a tear, the presence of a acromiocoracoid ligament with no histological lesion confirms that tears are not always associated with an impingement. Among cuff tear or impingement cases, there was a number of acromions with no bone lesion. Inflammatory lesions were not frequent. Unravelling the pathology of the degenerative shoulder is a complex process making interpretation and correlation with clinical signs and proposed therapeutic protocols difficult.
