Subacromial Shoulder Pain Research Articles

Interleukin-1-induced subacromial synovitis and shoulder pain in rotator cuff diseases.

To determine the relationship between the expression of interleukin-1beta (IL-1beta) and IL-1 receptor antagonists (IL-1ra) in the subacromial bursa and shoulder pain in rotator cuff diseases. Synovial specimens were analysed using various methods including reverse transcriptase-polymerase chain reaction (RT-PCR), immunohistochemistry and in situ RT-PCR. Thirty-nine patients with rotator cuff diseases were candidates. The degree of their shoulder pain was evaluated using a visual analogue scale. The mRNA expression levels of the cytokines were significantly correlated with the degree of pain [IL-1beta: r=0.782; secreted IL-1ra (sIL-1ra): r=0.756; intracellular IL-1ra (icIL-1ra): r=0.806, P<0.001, respectively]. The combined results of immunohistochemistry and in situ RT-PCR analysis indicated that both synovial lining and sublining cells produce IL-1beta, while synovial lining cells predominantly produce icIL-1ra and sublining cells secrete sIL-1ra. The differential regulation of the two forms of IL-1ra mRNAs may play an important role in shoulder pain in rotator cuff diseases, regulating IL-1-induced subacromial synovitis.

Increased substance P in subacromial bursa and shoulder pain in rotator cuff diseases.

The subacromial bursa is recognized as a site associated with the shoulder pain caused by rotator cuff disease in the middle-aged and elderly. Substance P is contained in primary afferent nerves, and its quantity increases during chronic pain. The amount of substance P in the subacromial bursa of patients with rotator cuff disease was examined. Radioimmunoassay and immunohistochemistry were employed to quantify and localize substance P. The preoperative pain level was measured with a visual analogue scale with 0 as no pain, 5 as moderate, and 10 as severe. Thirty-seven patients that had undergone operation were divided into two groups: one composed of 19 patients with subacromial bursitis and a partial-thickness tear of the rotator cuff (nonperforated cuff) and the other composed of 18 patients with a full-thickness tear (perforated cuff). Subacromial bursae obtained from seven fresh cadavers with no shoulder pain before death were used as controls. The visual analogue scale showed significantly greater pain in the group with the nonperforated rotator cuff than in the group with the perforated cuff. Consistent with these results, the amount of substance P in the subacromial bursa was significantly greater in the former group than in the latter. Nerve fibers immunoreactive to substance P were localized around the vessels, with a larger number of fibers in the group with the nonperforated rotator cuff. Therefore, an increased amount of substance P in the subacromial bursa appears to correlate with the pain caused by rotator cuff disease.

Neurohistology of the subacromial bursa in rotator cuff tear

This study was undertaken to identify and quantitate neural elements in the human subacromial bursa. Biopsy specimens of subacromial bursae were obtained from patients with rotator cuff tears and from cadavers of patients with no history of shoulder disorder (controls). We used a modified gold chloride method to characterize neural elements within the subacromial bursa. The population of intrabursal neural elements was calculated by computerized image analysis. The subacromial bursa demonstrated an extensive neural network: four morphological types of mechanoreceptors and many free nerve endings were identified. In general, there was an inverse relationship between the population density of neural elements and the extent of cuff tear. The population density of neural elements of the subacromial bursa associated with massive cuff tear was significantly lower than that observed in control shoulders. With regard to clinical symptoms, a significant correlation was established between the population density of neural elements in the subacromial bursa and shoulder pain at rest. Our investigation strongly suggests that the subacromial bursa is intimately involved in the perception of shoulder pain, providing an anatomical basis for afferent neural input in proprioceptive reflex arcs.

The commonest rheumatic complaints of over six weeks' duration in a twelve-month period in a defined Swedish population. Prevalences and relationships.

In 900 randomly selected individuals, 50-70 years old, we examined the prevalence over the preceding 12-month period of rheumatic complaints of more than 6 weeks' duration. We found them to represent a major health problem, with an overall prevalence of 37.8%, the predominant diagnoses being subacromial shoulder pain (6.7%), neck pain (6.5%), low back pain (6.3%), osteo-arthrosis (8.5%), and arthralgia (4.9%). With a prevalence of 1.0%, primary fibromyalgia was as common as rheumatoid arthritis (0.7%) and other chronic arthritides (1.1%). The prevalences of the different diagnoses were higher among participants whose data were obtained from personal investigation by a physician than among non-participants where data were obtained by interview, letter, and scrutiny of case records. The odds ratio from incurring more than one rheumatic disease was higher for subacromial shoulder pain and lowest for arthralgia and osteo-arthrosis.