J. F. Crossan

We studied five cadaver shoulders to determine the strength relationship of the four rotator cuff muscles. The mean fibre length and volume of each muscle were measured, from which the physiological cross-sectional area was calculated. This value was used to estimate the force which each muscle was capable of generating. The lever arm of each muscle about the humeral head was then measured and the moment exerted was calculated. The strength ratios between the muscles were more or less constant in the five specimens. Subscapularis was the most powerful muscle and contributed 53% of the cuff moment; supraspinatus contributed 14%, infraspinatus 22% and teres minor 10%. The force-generating capacity of the subscapularis was equal to that of the other three muscles combined.

AIM: To analyse patterns of gene expression for peptide regulatory factors in patients with Dupuytren's contracture. METHODS: Tissue samples (palmer fascia) from 12 patients with Dupuytren's contracture and 12 controls were studied using the reverse transcription/polymerase chain reaction (RT/PCR) technique. RESULTS: Tissue from patients with Dupuytren's contracture expressed a higher percentage of peptide regulatory factors than that of controls: interleukin-1 alpha (83% v 16%; p < 0.01); interleukin-1 beta (66% v 8%; p < 0.01); transforming growth factor beta (75% v 25%; p < 0.02); and basic fibroblast growth factor (66% v 25%; p < 0.05). Platelet derived growth factors alpha and beta were also expressed more commonly (66% v 33% and 25% v 16%, respectively), but these differences were not significant. CONCLUSIONS: The increased prevalence of expression for the above mRNAs in Dupuytren's tissue is relevant as interleukin-1, basic fibroblast growth factor, and transforming growth factor beta stimulate the growth of fibroblasts and transforming growth factor beta also enhances production of collagen and other extracellular matrix proteins. Excessive local release of these peptide regulatory factors may have an important role in the pathogenesis of Dupuytren's contracture.

A clinicopathological review of 23 patients (mean age, 67 years; range, 42-85 years) with chondrosarcoma of the bones of the hand was done. The mean follow up was 8.5 years. Eleven patients presented with a progressive painless swelling, 26% having had symptoms for over 10 years. The proximal phalanx was the commonest site. Initial clinical misdiagnosis as ganglion, bursa, gout, rheumatoid arthritis and a cyst occurred in five patients. Radiologically most lesions showed bone expansion, cortical destruction and soft-tissue extension. The majority was of high histologic grade (Evan's grade 2 & 3) with extensive myxoid areas. Five out of eight patients who were originally treated by curettage or excision had local recurrences compared to none treated by ray resection or amputation of phalanx (P=0.002). None had metastases. The low risk of metastases despite the high histologic grade indicates that chondrosarcomas of the hand behave differently from chondrosarcomas elsewhere.

This study compared the rates of proliferation and apoptosis of cells within nodules of Dupuytren's disease and nodules from patients that had been injected preoperatively with steroid (Depo-Medrone). It also compared the effects of steroids in apoptosis in cultured Dupuytren's cells and control fibroblasts from palmar fascia and fascia lata. Steroids reduced the rate of fibroblast proliferation and increased the rate of apoptosis of both fibroblasts and inflammatory cells in Dupuytren's tissue. Steroids also produced apoptosis of cultured Dupuytren's cells but not of palmar fascia and fascia lata cells.

The accumulation of inflammatory cells in synovial tissue was studied using indirect immunofluorescence assays on cell cultures and frozen tissue sections of healing rat digital flexor tendons. Flexor tendons were collected from rats 3, 7 and 14 days after crush injury. Tendon sheath and epithenon cells were isolated by sequential enzymic digestion and cultured for 2 days. Subpopulations of synovial and inflammatory cells were identified with MoAbs against cell surface glycoproteins present on B lymphocytes (CD45), T lymphocytes (CD2, CD4, CD8), macrophages (CD14) and endothelial cells. A phagocytosis assay was also used to identify macrophages. We report a substantial increase in the number of T lymphocytes (mainly helper/inducer) and phagocytotic cells with monocyte/macrophage surface markers in tendon sheath and epitenon 3 days after crush injury. The infiltration of inflammatory cells into synovial sheath and epitenon preceded an increase in fibronectin production by tendon cells which was seen 7 days after injury. To study the interaction between T lymphocytes and synovial cells in vitro, we established synovial fibroblast-like type B cell cultures and used stimulated and non-stimulated T lymphocytes in cell binding assays. We observed increased adhesiveness between unstimulated synovial cells and synovial cells previously cultured with activated and non-activated T lymphocytes. ELISA inhibition studies have shown an increase in fibronectin production by synovial fibroblasts co-cultured with stimulated CD4+ T lymphocytes. We suggest that the presence of inflammatory cells in synovial sheath and epitenon during tendon healing induces synovial fibroblasts and epitenon cells to increase their production of fibronectin, which provides a scaffold for subsequent adhesion formation.