An in vivo microfabricated scaffold for tendon repair.

A new type of in vivo tissue engineering system for tendon repair in situ after cut or crush of a flexor tendon is described. The system is based on the topographical reaction, alignment, migration and perhaps proliferation of tendon cells on micrometrically grooved substrates made in a biodegradable polymer. Macrophage trapping in the structure may also help to prevent inflammation. Tendon damage including crush and section injury is a fairly frequent occurrence. The conventional treatment is surgical repair, however frequently this leads, especially in hand wounds, to attachment of the tendon surface to the surrounding synovium, which is very undesirable. We present an approach based on using a biodegradable device to ensure that the healing of severed or crushed flexor tendons is aided, synovial adhesion prevented and the final result anatomically correct. The biodegradable sheath carries microgrooves fabricated into the polymer by embossing that orient and guide the cells towards each other from either side of the region of damage. After six weeks an apparently normal functional tendon is reformed.

Chondrosarcoma of small bones of the hand.

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.

The effect of steroids on Dupuytren's disease: role of programmed cell death.

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.

Dupuytren's disease. A model for the mechanism of fibrosis and its modulation by steroids.

Dupuytren's disease is a chronic inflammatory process which produces contractures of the fingers. The nodules present in Dupuytren's tissue contain inflammatory cells, mainly lymphocytes and macrophages. These express a common integrin known as VLA4. The corresponding binding ligands to VLA4 are vascular cell adhesion molecule-1 (VCAM-1) present on the endothelial cells and the CS1 sequence of the fibronectin present in the extracellular matrix. Transforming growth factor-beta (TGF-beta) is a peptide hormone which has a crucial role in the process of fibrosis. We studied tissue from 20 patients with Dupuytren's disease, four samples of normal palmar fascia from patients undergoing carpal tunnel decompression and tissue from ten patients who had received perinodular injections of depomedrone into the palm five days before operation. The distribution of VLA4, VCAM-1, CS1 fibronectin and TGF-beta was shown by immunohistochemistry using an alkaline phosphorylase method for light microscopy. In untreated Dupuytren's tissue CS1 fibronectin stained positively around the endothelial cells of blood vessels and also around the surrounding myofibroblasts, principally at the periphery of many of the active areas of the Dupuytren's nodule. VCAM-1 stained very positively for the endothelial cells of blood vessels surrounding and penetrating the areas of high nodular activity. VCAM-1 was more rarely expressed outside the blood vessels. VLA4 was expressed by inflammatory cells principally in and around the blood vessels expressing VCAM-1 and CS1 but also on some cells spreading into the nodule. TGF-beta stained positively around the inflammatory cells principally at the perivascular periphery of nodules. These cells often showed VLA4 expression and co-localised with areas of strong production of CS1 fibronectin. Normal palmar fascia contained only scanty amounts of CS1 fibronectin, almost no VCAM-1 and only an occasional cell staining positively for VLA4 or TGF-beta. In the steroid-treated group, VCAM-1 expression was downregulated in the endothelium of perinodular blood vessels and only occasional inflammatory cell expression remained. Expression of CS1 fibronectin was also much reduced but still occurred in the blood vessels and around the myofibroblast stroma. VLA4-expressing cells were also reduced in numbers. A similar but reduced distribution of production of TGF-beta was also noted. Our findings show that adherence of inflammatory cells to the endothelial wall and the extravasation into the periphery of the nodule may be affected by steroids, which reduce expression of VCAM-1 in vivo. This indicates that therapeutic intervention to prevent the recommencement of the chronic inflammatory process and subsequent fibrosis necessitating further surgery may be possible.

The effects of T cells and their products on in vitro healing of epitenon cell microwounds.

The purpose of the present investigation was to study the activity and behaviour of rat epitenon cells cultured in the presence of activated helper/inducer T lymphocytes and T-cell-derived cytokines interleukin-1 (IL-1), IL-2, transforming growth factor-beta (TGF-beta) and interferon-gamma (IFN-gamma). We measured the speed of healing of microwounded monolayers of epitenon cells as well as intercellular adhesion, cell proliferation and fibronectin production. The speed of monolayer healing was increased in the presence of activated CD4+ T lymphocytes and cytokines: TGF-beta > IL-2 > IL-1 > IFN-gamma. TGF-beta and IL-2 were also found to promote cell-cell adhesion; other cytokines had a minor effect. IL-2, IL-1 and IFN-gamma promoted [3H]thymidine incorporation in epitenon cells whereas TGF-beta had an inhibitory effect. Fibronectin production was studied with immunofluorescence staining methods. Activated CD4+ T lymphocytes and TGF-beta stimulated the deposition of fibronectin whereas other cytokines did not have a significant effect. Our results suggest that activated T lymphocytes and T-cell-derived cytokines, especially IL-2 and TGF-beta play a crucial role in the regulation of epitenon cell proliferation, adhesion and extracellular matrix production during in vitro microwound healing. As epitenon cells are the main cell type participating in tendon repair, factors regulating their activity may find application in clinical practice.

The accumulation of inflammatory cells in synovial sheath and epitenon during adhesion formation in healing rat flexor tendons.

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.

T-cell-mediated response in Dupuytren's disease.

The cause of Dupuytren's disease is unknown, but inflammatory cells might have a role. Enzymatic digestion of diseased tissue permits identification and immunofluorescent labelling of a cell subset displaying inflammatory cell morphology. Cytofluorimetry of this cell population demonstrated the presence of CD3-positive lymphocytes and expression of major histocompatibility complex (MHC) class II proteins. These results raise the possibility that Dupuytren's disease is a T-cell-mediated autoimmune disorder. The development of medical treatment on this basis may reduce the need for surgery, with its associated morbidity and high recurrence rates.

Abnormal growth factor and cytokine expression in Dupuytren's contracture.

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.

The relative strengths of the rotator cuff muscles. A cadaver study.

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.

Research for genetic and environmental factors in orthopedic diseases.

This is a review article of the past 40 years of research in Britain on the etiology of developmental disorders of the skeleton, covering both rare unifactorial diseases (chondroosteodystrophies) and common localized disorders (e.g., clubfoot and congenital dislocation of the hip) of multifactorial inheritance.

Bilateral failure of the capital femoral epiphysis: bilateral Perthes disease, multiple epiphyseal dysplasia, pseudoachondroplasia, and spondyloepiphyseal dysplasia congenita and tarda.

A radiographic survey of 25 patients with bilateral Perthes disease is compared with four inherited skeletal dysplasias also affecting the hip joints (45 patients with multiple epiphyseal dysplasia, 22 with spondyloepiphyseal dysplasia tarda, 18 with pseudoachondroplasia, and 17 with spondyloepiphyseal dysplasia congenita). The distinguishing features in relation to the pelvis and hip joint in the growing child are ascertained, in view of the importance of differentiating as early as possible the transient disorder of Perthes disease from the more serious progressive disorders.