Subtotal synovectomy was performed in the knee joints of New Zealand white rabbits. The changes noted in the articular cartilage as manifest by decreased metachromatic staining of the matrix were considered to indicate matrix degradation caused by the altered joint environment. The documentation of the enzyme changes suggests that the histological alteration in the articular cartilage noted after synovectomy may be mediated through the activation of endogenous chondrocyte lysozomal enzymes, particularly cathepsin and acid hydrolases

1. The clinical, radiological, operative and histological features of twelve aneurysmal bone cysts are recorded. 2. Attention is drawn to atypical features, and the problem of diagnosis is discussed. 3. It is recommended that treatment should be complete excision, except where this would interfere with function. 4. Various theories on pathogenesis are considered and favour given to the view that these cysts result from a local change in haemodynamics occurring possibly in a pre-existing lesion

The effect of cortisone on the repair of simple muscle injury was studied in rabbits. The histological findings in the crushed muscle are described for a period up to twenty-one days after injury. Cortisone defers the onset of muscle regeneration, and retards its progress, but it does not change the course of the repair process or alter its eventual outcome under the conditions of the experiment. This apparent refractoriness of repair of muscle, as compared with that of other connective tissues, is discussed

A four-year-old boy presented with a solitary bone cyst in the odontoid process and body of the axis. Plain radiographs showed a radiolucent lesion with extreme thinning of the cortex and MRI demonstrated a high signal intensity in the interlesional matrix. The cystic component extended into the body of the axis through a defect in the epiphyseal plate. At operation, the cavity of the cyst was found to contain serosanguineous fluid, and histological examination showed that it was lined by a thin layer of connective tissue. The cyst may have originated from a defect in the epiphyseal plate

In this study 201 elderly patients with femoral neck fractures were compared with 30 osteomalacic patients with the same injury. Hypocalcaemia and a raised alkaline phosphatase level are common biochemical abnormalities in elderly patients with femoral neck fractures. In only a minority of patients, however, were they associated with histologically proven osteomalacia. By using the combination of hypocalcaemia and a raised alkaline phosphatase it is possible to identify a subgroup (approximately 10% of all admissions) in whom osteomalacia is relatively likely

A 69-year-old man presented with a 20-year history of a slowly enlarging mass of the left index finger dating from a hammer injury. The mass was excised, and seen to have the characteristic histological appearance of an elastofibroma, a benign tumour-like growth usually found in the soft tissue of the back. Such a lesion has not previously been documented in the hand, which we consider surprising in view of the generally accepted traumatic aetiology of this entity and the susceptibility of the hand to injury

We reviewed histologically the incidence and pathogenesis of the deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the pseudocapsule, femoral and acetabular membranes and periprosthetic tissue at revision of 789 cases of failed total hip replacement. In 13, periprosthetic tissues were found to have deposits of CPPD crystals in areas of cartilaginous metaplasia; four also showed evidence of localised deposition of amyloid. None of the patients had a history of chondrocalcinosis in the hip or other joints. Cartilaginous metaplasia and other changes in periprosthetic tissues may predispose to the deposition of CPPD and associated localised amyloid

1. Two cases of haemangioma of the patella are reported. 2. In one case pain alone brought the patient for treatment; in the other, a pathological fracture was the first symptom. 3. In neither case was a firm diagnosis made before excision and histological examination of the patella. 4. In each case a good result followed removal of the patella: this is probably the best method of treatment. 5. The literature relating to haemangioma of bone and to tumours of the patella is briefly reviewed

We attempted to repair full-thickness defects in the articular cartilage of the trochlear groove of the femur in 30 rabbit knee joints using allogenic cultured chondrocytes embedded in a collagen gel. The repaired tissues were examined at 2, 4, 8, 12 and 24 weeks after operation using histological and histochemical methods. The articular defect filling index measurement was derived from safranin-O stained sections. Apoptotic cellular fractions were derived from analysis of apoptosis in situ using TUNEL staining, and was confirmed using caspase-3 staining along with quantification of the total cellularity. The mean articular defect filling index decreased with time. After 24 weeks it was 0.7 (. sd. 0.10), which was significantly lower than the measurements obtained earlier (p < 0.01). The highest mean percentage of apoptotic cells were observed at 12 weeks, although the total cellularity decreased with time. Because apoptotic cell death may play a role in delamination after chondrocyte transplantation, anti-apoptotic gene therapy may protect transplanted chondrocytes from apoptosis

We reviewed the records and radiographs of seven children who presented with knee pain, local tenderness over the medial femoral condyle, and radiological irregularity of the distal medial metaphysis of the femur suggestive of malignancy. In the five patients who had biopsies, histological changes were consistent with musculotendinous avulsion, and the dissection of ten cadavers confirmed the site to be the insertion of part of the adductor magnus. The recognition of this lesion and knowledge of its benign nature may avoid unnecessary anxiety and needless biopsy

We report 12 patients with infiltrating muscular lipomas of the lower limbs all treated by wide resection. During follow-up averaging seven years, the tumour recurred in five patients. Our results and those reported by others suggest that, in order to avoid recurrence, this tumour, although benign, should be treated by total excision of the muscle or by compartmental resection. Hormonal imbalance was suspected in 9 of the patients but an oestrogen receptor analysis of the histological samples proved negative

We review the case of a 58-year-old man with a benign osteoblastic lesion. This originated in the base of the right second metacarpal and eventually involved several adjacent bones, persisting for at least 27 years despite 11 operations. It was originally reported in the literature as a recurrent osteoid osteoma, but we believe it is more properly diagnosed as an aggressive osteoblastoma, since the histological pattern did not change over the years. The lesion has remained locally aggressive with no evidence of malignant characteristics

Using a simple method of quantifying fracture healing, 53 patients who had limb fractures and also severe head injuries were studied; they were compared with 30 patients who had limb fractures but no head injury. Those with head injuries had a greater healing response and united more rapidly. Radiological and histological analysis revealed that the terms "myositis ossificans" and "heterotopic bone" may be more appropriate than "fracture callus" to describe the healing response in these patients

The clinical, radiological and histological information on the fate of Kiel bone implants for anterior spinal fusion in four patients was evaluated. These implants were found to be unsatisfactory and further operations were required. Biopsies of the grafts showed that the Kiel bone was invaded by fibrous tissue but that it did not ossify or become incorporated into the underlying bone. However, it might provide temporary support to the grafted area. These findings indicate that the use of Kiel grafts does not seem to be justified in current orthopaedic practice

1. Four joints of three young haemophiliacs who died in traffic accidents have been examined. 2. All patients had received prompt specific treatment for intra-articular and other haemorrhages. 3. Major macroscopic and histological changes were seen in the joints, but these changes were not quite so severe as those described before the days of specific treatment. 4. The possibilities of preventing articular changes and of minimising the effect of blood in the joints are discussed

1. Of forty-seven patients with histologically proven myeloma of the spine, thirty-three had multiple lesions at the time of the first examination and fourteen were solitary. 2. Five of the solitary cases, in which the patients are alive and well without signs of dissemination four to fourteen years after diagnosis, are considered in detail and the differences in clinical presentation and prognosis are discussed. 3. A sixth case, described in detail, showed scattered osteolytic lesions after ten years

1. The use of acrylic cement in bonding femoral head prostheses to bone is described. 2. No sign of deterioration of the bond between the cement and bone has been seen in histological preparations up to three and a quarter years after operation, and no harmful effects have been recognised, or suspected, in 455 patients in whom it has been used. 3. The technique is considered justifiable in elderly patients where the medullary canal is large and the cortex of the femur is thin and brittle

We report the histological findings in post-mortem specimens obtained ten days, 17 days and seven weeks after implantation of hydroxyapatite-coated femoral components of hip arthroplasties. There was early deposition of woven bone on the hydroxyapatite ceramic, identical to that deposited on surviving cancellous trabeculae. The space between these deposits became bridged from both sides by new trabeculae, and there was no evidence of an inflammatory reaction or of fibrous tissue formation. The use of an hydroxyapatite coating seems to allow early, sound, secondary fixation of implants

We report the two- to four-year results following the insertion of the Leeds-Keio prosthetic ligament for chronic anterior cruciate deficiency. Virtually all the 20 patients were less disabled by instability, but objective results were good or excellent in only two-thirds and under anaesthesia the pivot shift sign was still positive in half. Arthroscopic and histological assessment in 16 patients failed to show the development of a functional neoligament, and the common appearance of a synovitic reaction to polyester particles gave concern

We have reviewed 20 cases of parosteal osteosarcoma treated by wide local resection and prosthetic replacement and followed up for six to 17 years. Limb function was excellent in 85%. One patient with grade III histological disease developed pulmonary metastases. Four patients had local recurrences, which were related to repeated preliminary biopsies, inappropriate siting of biopsy and vascular encroachment by the tumour. After this mode of treatment, the outcome was not related to medullary invasion by the tumour