1. This paper describes the macroscopic and microscopic changes that are seen in posterior intervertebral joints after anterior vertebral fusion. 2. We now have a reasonably clear view of the types of change seen under these circumstances. The type varies from case to case and in different parts of the same specimen. So far we have no clear idea of the sequence or the pattern that leads from the normal to complete fibrosis or osseous ankylosis. 3. Further experimental work is needed in order to build up a clear concept of the sequence of events and of their relative importance. To do this it will be necessary to immobilise joints for longer than before.
1. Direct injury to skeletal muscle results in fragmentation and necrosis of muscle fibres, though this is patchy in distribution. 2. The sarcolemmal basement membranes form the interface along which fibre regeneration takes place. 3. Phagocytosis of disorganised sarcoplasm is an essential prelude to the reconstitution of severely damaged fibres. 4. Regeneration of injured muscle begins with proliferation of basophilic cells probably originating from muscle satellite cells. After a few days typical myoblast nuclear chains are present. By a week following injury the chains of myoblasts have formed myotubes, which possess myofibrils and sarcomeres. 5. By twelve days in the monkey and by eighteen days in man the muscle fibre regenerative process shows many new fibres which have not reached a mature diameter. 6. Much collagen may be formed in the tissue space at the site of injury. It appears that as the muscle fibres increase in diameter the collagen decreases in extent. 7. In the monkey by three weeks the muscle at the fracture site appears normal. This is also true in the specimens examined at four, six and twelve weeks. 8. In the monkeys the injured limb was immediately used to run and jump. A parallel intense and early activity of muscle and joints was a cardinal point in the management of this series of fracture patients. The clinical results were satisfactory. 9. It is concluded that in both the monkey and in man, given active limb movements, permanent and functionally useful muscle regeneration occurs following soft-tissue injury associated with a bone fracture.
1. A primary subacute type of staphylococcal osteomyelitis has been described. It is the commonest form of osteomyelitis seen in East Africa, and the incidence appears to be increasing in Great Britain. 2. A review of the literature indicates that this is not a new disease but that in the past there has been some confusion in terminology. 3. The causative organism is a coagulase positive staphylococcus, but in a few instances a coagulase negative one has been isolated. The staphylococcus is thought to be of reduced virulence and in East Africa it is likely that the population has acquired an increased resistance to the staphylococcus. 4. Two radiologically distinct groups are recognised, depending on whether a bone abscess is present or not. In the first group there are two types of localised abscesses: the familiar Brodie's lesion and the less well recognised large bone abscess that occurs in the metaphysis of a long bone. While the pathology of the two types is similar, the radiological features are quite distinct. The lesions in the second group are characterised by extensive diaphysial changes, with or without metaphysial involvement, and an obvious abscess cannot usually be demonstrated. 5. The main clinical features are the long history, often weeks or months, before diagnosis; insignificant or absent general reaction to the infection and minimum physical signs. 6. Vertebral body osteomyelitis in adults is included because it generally presents as a subacute infection; the difficulties in distinguishing it from a tuberculous infection are outlined. 7. The most useful diagnostic aids are the staphylococcal antibody titres (especially in vertebral infections) and the erythrocyte sedimentation rate. A limited surgical exposure is usually required if the causative organism is to be isolated and empirical antibiotic therapy is to be avoided. The total and differential white blood count are so often normal in these patients that they are considered to be of no diagnostic value. 8. Curettage and local antibiotics together will cure the localised bone abscess. Other lesions may be effectively treated by systemic antibiotics alone, but in the later stages removal of sequestra and infected granulation tissue may be necessary. In this instance it is essential to make a planned incision and to cut a window in the bone large enough to expose the whole of the lesion; primary suture of the wound is advocated.
1. Cancellous bone grafting of the head of the femur in Perthes' disease accelerates reossification and thus shortens the period of treatment. 2. There is no evidence from this series of cases that the final shape of the head is affected for better or for worse by the operation of cancellous chip grafting, by the rate of regeneration of the head after operation or by the stage in the disease process at which the operation is done. 3. No relationship has been found between the shape of the head at the time of operation and its final shape. 4. A larger series of cases is needed to determine the value of bone grafting in Perthes' disease of the hip.
The experiments were performed to answer three main questions. These and our answers may be summarised as follows.
1. A massive proliferation of fibroblasts occurred from the cut periosteum, from the cut joint capsule, and to a lesser extent from the medullary canal. 2. Fibroblasts grew centripetally in the first few weeks after operation, attempting to form a "fibroblast cap" to the cut bone end. 3. Fibroblasts of this cap near the cut bone spicules metamorphosed to become prechondroblasts, chondroblasts laying down cartilage matrix, and hypertrophied (alkaline phosphatase-secreting) chondrocytes lying in a calcified matrix. 4. This calcified cartilage matrix was invaded by dilated capillaries probably bearing osteoblasts which laid down perivascular (endochondral) bone. 5. Some of the cells of projecting bone spicules died and their matrix was eroded in the presence of many osteoclasts. 6. In the control experiments of simple excision of the radial head new bone was produced at the periphery only by processes (3) and (4). This sealed off the underlying peripheral cortical bone from the superficially placed peripheral articular surface of fibrocartilage. At about a year from operation the central portion of the articular surface was still formed of bare bone, or of bone spicules covered by a thin layer of irregularly arranged collagen fibres. The opposite capitular articular cartilage was badly eroded.
The cartilage of fixed autotransplants and homotransplants underwent similar gradual replacement, and took about the same time in each case. The dead bone, implanted in association with the cartilage in both cases, acted as a nidus for hyaline cartilage production by chondrocytes derived from fibroblasts. This cartilage underwent endochondral ossification. This observation suggests that induction by non-cellular osseous material is a factor in chondrification and ossification. All the implants functioned as temporary articular menisci or in some cases as temporary radial articular surfaces. They were always replaced by a permanent fibrocartilaginous meniscus, or a fibrocartilaginous articular surface. An implant did, in fact, always act as a temporary protecting cap and mould for the subjacent growth offibroblasts which was necessary for the production of a satisfactory new joint surface.
1. The anatomical and physiological principles underlying the operation of ischio-femoral arthrodesis by an anterior approach are discussed. 2. The technique of the operation is described.
