Sixty-three knees with chronic ligamentous instability treated with flexible carbon fibre are reviewed. Assessment was by pre-operative and postoperative grading of function in work and sport, together with a subjective evaluation of the result based on stability. Fifteen knees had collateral repairs, seven had cruciate repairs and 41 had combined collateral and cruciate repairs. Overall, 71% of knees showed improvement in function and 67% had good or excellent results subjectively. Clinical examination did not correlate well with the patient's evaluation of the result. Nineteen unselected cases with intra-articular (cruciate) carbon fibre had arthroscopies. Infiltration of collagen tissues into the cruciate replacement was a slower process than at the extra-articular (collateral) site. There was no clinical or macroscopic evidence of synovitis but microscopically there was evidence of synovial irritation

To study the anatomy of subarticular bone and cartilage, fresh specimens of cartilage on bone from the human shoulder, hip and knee were treated with bleach or papain, or were fixed and decalcified. All were compared using scanning electron microscopy. Papain digestion selectively removed cartilage to the tidemark. The tidemark contour was highly variable; irregularities were indirectly related to degenerative lesions and were most prominent in peripheral non-weight-bearing areas of joints with central fibrillation. Decalcification exposed the interface between the bone and calcified cartilage. Collagen fibrils in articular cartilage did not interdigitate with those of bone. The subchondral bone was appositional, avascular, smooth and very thin in most areas of human joints. Perforations through subchondral bone or calcified cartilage were rare. Bleach maceration destroyed important details

We have performed an arthroscopic and histological study of the remodelling process of allogeneic tendons transplanted into the human knee as anterior cruciate ligament substitutes. Arthroscopic observations from six weeks to 55 months after operation showed that the grafts were viable, and that early surface hypervascularity subsided with time; moreover, these appearances remained unchanged from 11 months postoperatively onwards. Histological studies from three to 55 months after operation showed that all the grafts were infiltrated with fibroblasts, and that cellularity in their substance reduced with time, remaining unchanged from 18 months onwards; the collagen bundles were aligned as in a normal ligament from six months onwards. These findings suggest that the grafts reach maturity within the first 18 months and remain unchanged as viable ligaments thereafter

Six patients are described with idiopathic osteoporosis which began between the ages of 4 and 16 years. In four children the disorder was mild with pain in the back, vertebral collapse, qualitatively normal iliac bone biopsies, variable calcium balance and spontaneous recovery. The two remaining patients had progressive bone disease with deformity. One with a previously normal skeleton developed changes similar to those of osteogenesis imperfecta; in the other patient, who rapidly developed structural collapse associated with severe metaphysial osteoporosis, treatment was ineffective and the histological appearances of the bone suggested osteoblastic failure. Quantitative bone histology in four patients showed no evidence of excessive active resorption; and the ratio of Type III to Type I collagen in the skin was normal, in contrast to the findings in osteogenesis imperfecta. The significance of this study in relation to previous accounts is reviewed

Two distinct lesions affect the articular cartilage of the patella. Surface degeneration occurs particularly on the odd facet; it is age dependent, often present in youth and it becomes more frequent with increasing age. It probably does not occasion patello-femoral pain in youth, but may predispose to degenerative arthritis in that joint in later years and is regarded as a consequence of habitual disuse. The term "basal degeneration" is used to describe a lesion in which there is a fasciculation of collagen in the middle and deep zones of cartilage without, at first, affecting the surface. It was found astride the ridge separating the medial from the odd facet in twenty-three adolescents who had complained of prolonged patello-femoral pain. They were treated by excision of the disc of affected cartilage, with relief of pain in most cases. The pathogenesis of basal degeneration is related to the functional anatomy of the patella

1. The lines of fracture confirm the suggestions of earlier authors on the lines of strength in cartilage, with the additional feature of a transverse plane of weakness at the apex of the calcified zone. 2. The normal nutrition of cartilage is synovial, and access of a free blood supply is followed by destruction of hyaline articular cartilage. 3. Minor traumatic events in the articular lamella are common, particularly in osteoarthritic joints; the results of these on the cartilage are like the changes of osteoarthritis. 4. The removal of uncalcified cartilage can be described in two stages of a physico-chemical kind; the removal of calcified cartilage is a single cellular process. 5. There is evidence that the carbohydrate moiety of cartilage is present in two separable phases, one fixed to collagen, the other free. 6. The repair mechanisms after fracture are those available to restore the damage of osteoarthritis, and reasons can be shown why in fact they are ineffective

The clinical features, investigation, treatment and outcome of two adults with fibrogenesis imperfecta ossium are described. In this rare acquired disorder of bone, normal lamellar collagen is replaced by structurally unsound collagen-deficient tissue, which leads to extreme bone fragility and ununited fractures. Transmission microscopy and SEM showed striking ultrastructural changes in bone structure and mineralisation. Both patients had monoclonal IgG paraproteins in the plasma and one excreted monoclonal lambda light chains in the urine. No abnormal plasma cells were found in the bone marrow and there was no evidence of amyloid deposition in the tissues. In both patients initial treatment with 1 alpha-hydroxycholecalciferol appeared to be ineffective, but in one, repeated courses of melphalan and corticosteroids over three years together with 1 alpha-hydroxycholecalciferol produced striking clinical and histological improvement. The findings in these and other patients strongly suggest that paraproteinaemia is an integral feature of fibrogenesis imperfecta ossium, and this needs further investigation

Unlike hyaline cartilage, mandibular condylar cartilage can respond to injury by complete healing. We have used the reparative potential of mandibular cartilage to promote repair of defects in a hyaline cartilage joint surface. In 12 adult marmosets, articular fibrocartilage from the mandibular condyles was transplanted into full-thickness defects created in the femoral condyles. Additional defects acted as an ungrafted control group. The grafted defects showed good incorporation of the transplant with restoration of the articular surface within six months. Repair was by proliferation of the fibrocartilaginous graft and chondrogenesis of hyaline cartilage. The repopulating cells were distributed in a matrix of maturing collagen and sulphated glycosaminoglycans. Ungrafted control defects were only partly repaired with fibrous tissue, leaving articular deficiencies. We conclude that transplanted mandibular fibrocartilage can promote reconstitution of wounded hyaline cartilage joint surfaces in primates

In order to determine whether an allogeneic tendon could be used to replace an extra-articular ligament, the right medial collateral ligament from 11 adult dogs was replaced with a fresh-frozen allogeneic patellar tendon. At each of 3, 6, 15, 30 and 52 weeks postoperatively, one dog was killed for micro-angiographical and histological studies; at 52 weeks the remaining six dogs were killed for tensile testing. Micro-angiograms showed that the allogeneic tendon was revascularised with infiltration of the mesenchymal cells from the surrounding tissues and both ends of the graft. Histologically, the alignment of the fibroblasts and collagen bundles became more regular over time, without any immunological rejection. A biomechanical study performed at 52 weeks found no significant difference in stiffness or ultimate load between normal and reconstructed ligaments. Fresh-frozen allogeneic tendons are therefore considered useful for extra-articular ligament reconstruction

The fine structure of palmar fascia from patients with Dupuytren's contracture (DC) was compared with that from patients with carpal tunnel syndrome (CTS). In contrast to previous assumptions, the ultrastructure of fibroblasts both in vivo and in vitro from DC and CTS appeared identical, indicating that myofibroblasts are not specific to DC. The major differences between DC and CTS were: 1) a sixfold and fortyfold increase in fibroblast density in cord and nodular areas of DC compared with CTS; 2) a more disorganised pattern of collagen fibrils in DC; and 3) markedly narrowed microvessels surrounded by thickened, laminated basal laminae and proliferating fibroblasts in DC compared with CTS. To account for these morphological changes a hypothesis is presented which proposes that oxygen-free radicals cause pericytic necrosis and fibroblastic proliferation. This hypothesis provides a potential avenue for therapy of DC and other fibrotic conditions

Aims

The aim of this study was to investigate the influence of age on the cost-effectiveness of arthroscopic rotator cuff repair.

We describe a new method of biological repair of osteochondral defects. In rabbit knees an osteochondral defect was reconstructed with a callo-osseous graft made of a superficial sheet of medullary fracture callus attached to a base of cancellous bone. This was taken from the iliac bone of the same animal which had been osteotomised ten days earlier. The reparative tissues were evaluated for 24 weeks by quantitative histology, biochemical analysis of the uronic acid content, and immunohistochemical staining of collagen constituents. The callo-osseous graft provided significantly faster and better repair of the articular surface than an untreated defect or a callo-osseous graft in which the cells had been devitalised by irradiation before transplantation. Our findings indicate that the callo-osseous graft contributes to the repair process by providing both favourable extracellular matrices and pluripotential mesenchymal cells. Our study tested the hypothesis that early medullary callus generates hyaline cartilage instead of bone after transfer to an articular surface

Aims

To assess the effect of physical exercise (PE) on the histological and transcriptional characteristics of proteoglycan-induced arthritis (PGIA) in BALB/c mice.

Biochemical changes in the articular cartilage of the knees of mature dogs, one with natural and four with surgically induced osteoarthritis, have been investigated. The four dogs were killed three, six, nine and forty-eight weeks after division of the right anterior cruciate ligament, the left knees serving as controls. The cartilage of the joints operated on was thicker and more hydrated than the control cartilage; the proteoglycans were more easily extracted and had higher galactosamine/glucosamine molar ratios. The proportion of proteoglycans firmly associated with collagen, and hence not extractable, diminished before fibrillation was demonstrable by indian ink staining of the surface. These biochemical changes were present throughout the entire cartilage of the joints operated on of the dogs killed more than three weeks later, and of the dog with natural osteoarthritis. The results suggest that in response to altered mechanical stresses the chondrocytes synthesise proteoglycans that contain more chondroitin sulphate relative to keratin sulphate than normally, as in immature articular cartilage

Despite widespread use of radiofrequency (RF) shrinkage, there have been no animal studies on the effects of post-operative immobilisation on the histological properties of the shrunken tissue. We have therefore examined the role of post-operative immobilisation after RF shrinkage with special emphasis on the histological properties of collagenous tissue. One patellar tendon of 66 New Zealand White rabbits was shrunk. Six rabbits were killed immediately after the operation. Twenty rabbits were not immobilised, 20 were immobilised for three weeks and 20 for six weeks. Fibroblasts, collagen and vascular quality and density were evaluated on sections, stained by haematoxylin and eosin. Nine weeks after operation the histological properties were inferior to those of the contralateral control tendons. Shrunk tendons did not return to normal at any time after operation irrespective of whether the animals had been immobilised or not. All the parameters improved significantly between zero and three weeks after operation. Immobilised tendons tended to have a better and faster recovery. Careful rehabilitation is imperative after RF shrinkage. Immobilisation aids recovery of the histological properties. Our findings in this animal model support a period of immobilisation of more than three weeks

Objectives

The aim of this study was to investigate the biomechanical effect of the anterolateral ligament (ALL), anterior cruciate ligament (ACL), or both ALL and ACL on kinematics under dynamic loading conditions using dynamic simulation subject-specific knee models.

We compared the effects of continuous passive motion with those of intermittent active motion on the results of the resurfacing with autogenous periosteal grafts of full-thickness defects on the articular surface of rabbit patellae. Of 45 rabbits with defects, 30 received grafts. Fifteen of these had continuous passive motion for two weeks and intermittent active motion for four weeks; the other 15 had intermittent active motion for six weeks. In 15 the defects were not grafted (control group) and they had intermittent active motion for six weeks. Ten more rabbits had a sham operation. Six weeks after surgery, the results were assessed by the gross appearance, histology, histochemistry, immunohistochemistry and electron microscopy. By all assessments the quality of neochondrogenesis produced by periosteal grafts was superior to that in ungrafted defects (p less than 0.05) and the results in continuous passive motion treated animals were superior to those in intermittent active motion treated animals (p less than 0.05). The periosteal grafts produced hyaline cartilage containing type II collagen but the organisation of its fibres was irregular

In a clinical, radiological and biochemical study of forty-two patients from Oxford with osteogenesis imperfecta, it was found that patients could be divided simply into mild, moderate and severe groups according to deformity of long bones. In the severe group (seventeen patients) a family history of affected members was uncommon and fractures began earlier and were more frequent than in the mild group (twenty-two patients); sixteen patients in the severe group had scoliosis and eleven had white sclerae; no patients in the mild group had white sclerae or scoliosis. Radiological examination of the femur showed only minor modelling defects in patients in the mild group, whereas in the severe group five distinct appearances of bone (thin, thick, cystic and buttressed bones, and those with hyperplastic callus) were seen. The polymeric (structural) collagen from skin was unstable to depolymerisation in patients in the severe group, but normal in amount, whereas the reverse was found in the mild group. This division according to long bone deformity may provide a basis for future research more useful than previous classifications

Objectives

Osteoporosis is a metabolic disease resulting in progressive loss of bone mass as measured by bone mineral density (BMD). Physical exercise has a positive effect on increasing or maintaining BMD in postmenopausal women. The contribution of exercise to the regulation of osteogenesis in osteoblasts remains unclear. We therefore investigated the effect of exercise on osteoblasts in ovariectomized mice.