1. Three cases of metaphysial fractures in infants are described. Obstetrical trauma was probably responsible in two cases, and in the third case direct injury was admitted by the parents. 2. These fractures are associated with bone destruction and periosteal new bone formation in the metaphyses. They are important because they can be confused with syphilis, tuberculosis, scurvy, osteomyelitis and neoplasm. 3. The fractures respond to conservative treatment and usually heal rapidly in a matter of weeks

1. Osteotomy for osteoarthritis of the hip induces a fibrin layer over the exposed bone which forms the basis of a fibrocellular protective mantle that can differentiate towards cartilage. 2. The process is accompanied by bone remodelling, which reduces sclerosis, resolves osteolytic foci and, in company with bone formation in the fibrous mantle, restores the subchondral plate. 3. Many important aspects of the pathogenesis of osteoarthritis and of its partial repair by osteotomy remain to be elucidated

The nuclide bone-scan will reliably diagnose Perthes' disease with a sensitivity of 0.98 and a specificity of 0.95. The comparable figures for radiographic sensitivity and specificity are respectively 0.92 and 0.78. In addition, it is possible on the scan to recognise the onset of revascularisation of the femoral capital epiphysis some months before there are radiographic signs of new bone formation. Scintigraphy also suggests that in some cases of transient synovitis there may bae a period of reversible ischaemia of the capital epiphysis, which may have relevance to the pathogenesis of Perthes' disease

Chronic recurrent multifocal osteomyelitis (CRMO) is characterised by an insidious onset of fever, local swelling and pain in affected bones, and radiological abnormalities suggestive of osteomyelitis. The histopathological features in 14 patients are described. Morphologically CRMO begins as an acute inflammatory process with a predominance of polymorphonuclear leucocytes, which occasionally form an abscess and osteoclastic bone resorption. At a later stage the predominant features are lymphocytes in the inflammatory infiltrates and occasional granulomatous foci and sigans of bone formation. The clinical course may be prolonged for many years

1. The results of the present investigation indicate that in the foetal rat the juxta-epiphysial vascular bed consists of a dense irregular network of sinusoids in direct contact with the growth cartilage, supplied by end-arteries, and drained by a profusion of metaphysial sinusoids. 2. The circulation is a closed one–that is, the endothelium is unbroken in its continuity and microhaemorrhages do not occur against the cartilage. 3. It is possible that juxta-epiphysial endothelial cells or their derivatives are chondrolytic, and that they participate directly, together with other mesenchymal derivatives, in the removal of cartilage as a preparatory stage in enchondral bone formation

Bone is a dynamic tissue with a quarter of the trabecular and a fifth of the cortical bone being replaced continuously each year in a complex process that continues throughout an individual’s lifetime. Bone has an important role in homeostasis of minerals with non-stoichiometric hydroxyapatite bone mineral forming the inorganic phase of bone. Due to its crystal structure and chemistry, hydroxyapatite (HA) and related apatites have a remarkable ability to bind molecules. This review article describes the accretion of trace elements in bone mineral giving a historical perspective. Implanted HA particles of synthetic origin have proved to be an efficient recruiting moiety for systemically circulating drugs which can locally biomodulate the material and lead to a therapeutic effect. Bone mineral and apatite however also act as a waste dump for trace elements and drugs, which significantly affects the environment and human health.

Cite this article: Bone Joint Res 2020;9(10):709–718.

Aims

Bone demonstrates good healing capacity, with a variety of strategies being utilized to enhance this healing. One potential strategy that has been suggested is the use of stem cells to accelerate healing.

We studied the precise role of the fracture haematoma in healing by the experimental transplantation of the haematoma at two days and four days after fracture of the rat femur to subperiosteal and intramuscular sites. We used bone marrow and peripheral blood haematomas for control experiments. The transplanted two-day fracture haematoma produced new bone by endochondral ossification at the subperiosteal site, but not at the intramuscular site. Four-day fracture haematoma produced new bone formation at both subperiosteal and intramuscular sites. These results suggest that fracture haematoma has an inherent osteogenetic potential

We examined the cellular responses to various particles injected into the knees and the intramedullary femoral cavities of rats in the presence of polymethyl-methacrylate (PMMA) plugs. The intra-articular particles were mainly ingested by synovial fibroblasts. Increased numbers of macrophages were not detected and there was only a slight increase in synovial thickness. Cellular responses in the intramedullary space were similarly mild and bone resorption around the PMMA plug did not occur. Bone formation was inhibited only by polyethylene particles. In contrast to current views, our study shows that wear particles per se do not initiate bone resorption

Three madreporic prostheses in two patients were examined to evaluate resorption and formation of the surrounding bone tissue. All three prostheses were firmly fixed and had no clinical or radiographic signs of loosening. Transverse sections were examined by scanning electron microscopy at 40 days, 11 months and 2.5 years after implantation. The findings suggest that adaptive bone remodelling varies along the length of the stem; that bone resorption and formation are related to the time after implant; and that new bone formation (woven bone) can be found very close to the madreporic surface

A cortical bone graft on a muscle pedicle was taken from the ulna and transferred to bridge a complete defect of the radius in 16 dogs. In 14 control dogs a free graft was used, that is, one without a muscle pedicle. Union in the group with pedicle grafts was far superior to that in the group with free grafts, mainly because in those with pedicle grafts there was good subperiosteal new bone formation from active viable periosteum. In six of the pedicle grafts the viability of some osteocytes was retained over a 12-week period and in five the graft was almost completely replaced by new bone

1. Tetracycline labelling methods have been used to measure the rate of growth in length and the rate of growth in width of the tibia of the normal rat. 2. The main limitations of the tetracycline methods are that in very young animals the bands of labelled bone are indistinct and remodelling occurs quickly; in animals nearing maturity, the growth in width is very slow and periods of at least fourteen days are required to give reliable results. 3. The tetracycline labelling methods can be used also to determine changes in the basic processes of bone formation and bone resorption

A retrospective review of 148 consecutive porous-coated hip arthroplasties (PCA) showed an incidence of thigh pain of 13% one year after surgery, and 22% at two years. Positive correlations were made with femoral stem subsidence (greater than 2 mm) and with distal periosteal and endosteal bone formation. No positive correlations were made with parameters of bone quality or component fit. Resolution of pain occurred in one-third and an anti-inflammatory agent produced partial relief in two-thirds of the patients. We conclude that thigh pain is secondary to stem instability with distal stress transfer in the absence of stable proximal fixation

We studied the effects of high-dose irradiation on the mechanical properties and morphology of cortical bone in rabbits for 52 weeks after a single dose of 50 Gy of electron-beam to the tibia. After four weeks, the bending strength of the irradiated bone was unchanged, but at 12 weeks, the strength had decreased significantly. At 24 weeks after irradiation mean strength was less than half of controls but by 52 weeks there was a tendency toward recovery. Similar, synchronous changes of damage and recovery were seen in cortical porosity, haematopoietic cells in the bone marrow and endosteal new bone formation

Operation on the hips of patients with myelomeningocele is often followed by stiffness or ankylosis. Excision of the upper end of the femur for this condition frequently fails because of extensive new bone formation. Twelve excisions in eight patients are reported. Six of these patients had recently had spinal fusion operations; the consequent loss of ability to compensate for hip stiffness by spinal flexion had made sitting difficult or impossible. Excision or even re-excision of the upper femur failed in most cases. Careful assessment of hip mobility before spinal operations in these patients is essential and osteotomy rather than excision of the upper femur is advised

1. The bone changes in four autopsied cases of Cushing's syndrome are described. The changes take the form of osteoporosis, which is most marked in the spine and the ribs. 2. The osteoporosis results from impaired osteoblastic bone formation in the presence of a normal degree of osteoclastic bone resorption. 3. Histological abnormalities of fracture callus in Cushing's syndrome indicate interference with the proliferation of osteoblasts and cartilage cells and with the formation of new tissue by these cells. 4. The bone changes in Cushing's syndrome are comparable with those produced in experimental animals by the administration of A.C.T.H. or cortisone

The method of producing osteogenic sarcoma in rabbits by the injection of beryllium in the form of "zinc beryllium silicate" is presented. In five of ten animals which had such injections, osteogenic sarcomas developed several months later. There was new bone formation in the medullary cavities of the long bones before malignant changes were apparent. It is of particular interest to note that there was atrophy of the spleen in those animals in which bone tumours developed, whereas the spleen seemed to be quite normal in the rabbits which did not develop bone tumours. The tumours usually developed in the metaphysial regions. More than one tumour often developed in the same animal

Arthroplasty of the hip using an interposed multi-layered cap of amniotic membrane is reported in 28 patients with tuberculous arthritis. The disease had been present from one to seven years, and five patients had multiple discharging sinuses. Follow-up was from 30 to 46 months. Amniotic tissue caused no inflammatory reaction, or obvious rejection, and 25 patients were free of symptoms, with a good range of movement and a stable joint. The three failures were caused by dislocation, fracture of the femoral neck and extra-articular bone formation respectively. Amniotic arthroplasty seems to be capable of providing a painless, mobile and stable joint in patients with tuberculosis of the hip

1. A pathological study has been made of eight femurs containing acrylic Judet type prostheses, in patients who had died two to thirteen weeks after arthroplasty. 2. Haemorrhage occurs into the tunnel and into a limited zone of the spongy bone around the tunnel. Organisation of the blood clot is evident at two weeks and new bone formation appears shortly afterwards. At eight weeks the tunnel is lined by a fibrous membrane. Further fibrosis and new bone growth tend to establish a new surface, healing the wound in the bone and sequestrating the foreign body. 3. There is no evidence that the intact methyl-methacrylate appliance had exerted any toxic action on the tissues