A longitudinal incision resembling a bucket-handle tear was made in the menisci of 8 rabbits, 6 dogs, 11 pigs and 12 sheep. In some of the animals of each species the cut was repaired by suturing, and in others it was not. Gross inspection, as well as examination by light and electron microscopy, showed that no healing had occurred after six months in the sutured or the unsutured wounds and that the meniscus was incapable of significant intrinsic repair. In a second experiment longitudinal, transverse and T-shaped cuts were made in the menisci of 12 sheep, and a flap of synovium was sutured into the wound. Three months later there was clear evidence of healing by the formation of cartilaginous tissue. Examination by light and electron microscopy showed that the newly formed repair tissue, possibly derived by metaplasia from the synovium, had a morphology intermediate between hyaline cartilage and fibrocartilage. Synovial implantation may therefore be considered as an alternative to meniscectomy in the management of the torn meniscus

Ferrography is a technique for analysing wear by means of the magnetic separation of wear particles. To evaluate its application in human joints, the results of the ferrographic analysis of saline washings of symptomatic human knees were compared with the results of the arthroscopic examination of the same knees. Ferrography was found to be an extremely sensitive monitor of articular erosion, with a resolution far greater than that of arthroscopy. This was particularly apparent with knees suffering from a torn anterior cruciate ligament: arthroscopy detected no damage to the cartilaginous surfaces whereas ferrography detected a substantial level of "microdamage". The spectrum of wear particles showed qualitative and quantitative alterations depending upon the condition of the knee. Ferrography thus holds much promise as a potential differential diagnostic technique of great sensitivity, with particular relevance to the very early changes which precede clinical symptoms. Study of wear particles is also justified by evidence indicating an active role in the pathophysiological progression of arthritis

This review of 27 cases serves to emphasis that periosteal chondrosarcoma and periosteal osteosarcoma are two distinct entities. Clinically, periosteal chondrosarcoma is less painful than periosteal osteosarcoma and runs a slower course. Radiographically, periosteal chondrosarcoma tends to affect the metaphysis and contains granular or "popcorn" opacities; while periosteal osteosarcoma more often affects the mid-diaphysis and shows lytic lesions with some spicules of reactive bone perpendicular to the underlying cortex. Histologically, periosteal chondrosarcoma shows lobular well-differentiated cartilage with Grade I or II (rarely Grade III) malignancy; periosteal osteosarcoma has a chondroid matrix with some osteoid component and Grade II or III malignancy. The prognosis in periosteal chondrosarcoma is good; conservative surgery is usually effective and metastases are very uncommon. In periosteal osteosarcoma the prognosis is less satisfactory but is better than that of other osteosarcomata; wide surgical excision is, however, needed and the incidence of metastases is about 15 per cent

Allografts of immature joint cartilage from the knees of lambs were transferred heterotopically into an intramuscular site in animals which had been presensitised by two sets of skin grafts from the same donors. All of these grafts were found to be largely destroyed by the immune response as early as four weeks after transfer. Similar grafts transferred orthotopically into the knees of the recipients, on the other hand, were found to be thriving even after twelve weeks and evoked a minimal response. Heterotopic autografts also provoked a mild though non-specific inflammatory reaction which the orthotopic grafts did not. It is concluded that cartilage matrix is capable of protecting grafts to a remarkable degree even from a severe immunological assault but only when the nutrition is adequate. It is suggested that the conflicting results of similar previous experiments may be explained by variations in the nutritional state of the graft which may be affected by the technique of transplantation used

The alkaline phosphatase activity of pre-osseous tibial cartilage of rachitic bone stored in the deep freeze for two weeks at -25 degrees centigrade was only slightly less than that of fresh controls from the same animals. The deep frozen pre-osseous tissue did not calcify in in vitro calcifying media containing either inorganic phosphorus or organic phosphate ester. The fresh controls calcified equally well in both media. In addition, after deep-freeze storage the tissue hydrolysed the organic phosphate to the same degree as did the fresh tissue. Bones heated at 65 degrees centigrade will calcify in vitro after calcium chloride treatment despite the destruction of phosphatase activity. It appears unlikely that a relationship exists between alkaline phosphatase and the minimal system required for calcification of pre-osseous cartilage in vitro. These findings do not exclude the possibility that alkaline phosphatase plays some critical role in vivo

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

Surgical dislocation of the hip is rarely undertaken. The potential danger to the vascularity of the femoral head has been emphasised, but there is little information as to how this danger can be avoided. We describe a technique for operative dislocation of the hip, based on detailed anatomical studies of the blood supply. It combines aspects of approaches which have been reported previously and consists of an anterior dislocation through a posterior approach with a ‘trochanteric flip’ osteotomy. The external rotator muscles are not divided and the medial femoral circumflex artery is protected by the intact obturator externus. We report our experience using this approach in 213 hips over a period of seven years and include 19 patients who underwent simultaneous intertrochanteric osteotomy. The perfusion of the femoral head was verified intraoperatively and, to date, none has subsequently developed avascular necrosis. There is little morbidity associated with the technique and it allows the treatment of a variety of conditions, which may not respond well to other methods including arthroscopy. Surgical dislocation gives new insight into the pathogenesis of some hip disorders and the possibility of preserving the hip with techniques such as transplantation of cartilage

Objectives

It has been hypothesized that patellofemoral pain, a common knee condition in adolescents and young adults, may be a precursor of degenerative joint changes and may ultimately lead to patellofemoral osteoarthritis. Since both conditions share several mechanical disease characteristics, such as altered contact area between the femur and patella and increased joint stress, we investigated whether these conditions share similar and different shape characteristics of the patella compared with normal controls.

Radiographs of 155 Indian children were examined to identify the acetabular changes which occur in Perthes' disease. These changes included osteoporosis of the acetabular roof, irregularity of contour, premature fusion of the triradiate cartilage, hypertrophy of articular cartilage and changes in dimensions. These changes tended to be more marked in older children and when more than half of the femoral epiphysis was involved. Comparison with 25 cases of Perthes' disease from Liverpool showed the same picture. Several of the acetabular changes noted during the active stages were also seen in a series of 24 adult hips after Perthes' disease. Radio-isotope scans of the hips of 27 children with Perthes' disease showed a consistently increased uptake in the acetabulum on the affected side, indicative of a local increase in vascularity and metabolic activity. It was possible to postulate a working model for the pathogenesis of all the acetabular changes. A number of statistical correlations suggest that most of the changes have a bearing on the final outcome

Six cases of osteochondritis dissecans patellae have been studied in five patients in an attempt to clarify the aetiology and prognosis. Assessment of the results of treatment was performed using a standard protocol. The thirty-four previous case reports in the literature are reviewed. In four of the five patients symptoms began after flexing the knee under load and three showed patellar subluxation on tangential radiographs. Thus, repetitive shearing stress on the patellar surface is thought to be an important aetiological factor. The indication for operation is a loose osteochondral fragment either wholly or partly detached from the articular surface of the patella. Vertical excision of the affected area of articular cartilage with drilling of the underlying bone gave two "good" and two "excellent" results. Healing of the drilled area and maintenance of the cartilage space was seen in radiographs of all four cases so treated. This simple method of treatment, which probably causes filling of the defect in the surface by fibrocartilage, is recommended

This paper describes a study in the human femur of the relationship between cell division in growth cartilage and overall bone growth. Growth rates for the distal femur from birth to eighteen years were determined from serial radiographs available from the Harpenden Growth Study; An average of 1-4 cm/year was found for the ages of five to eight years. The development of the growth plate is illustrated in a series of photomicrographs of femur sections. These sections were also used for quantitative histology; The length of the proliferation zone was estimated from cell counts to be twenty-four cells per column. On the basis of this value and the measured growth rate, an approximate mean cycle time of twenty days was found for the proliferating cells of the human growth plate. Since the corresponding cycle time is two days for rodent growth plates, which also have a different structure, it is unwise to extrapolate the findings in this tissue from mouse to man

1. Experimental work with piglets supports the theory that diminished blood supply to the femoral head not only causes necrosis of the epiphysis but also a decrease in cartilage cell production in the germinal layer of the epiphysial plate, thus causing decreased longitudinal bone growth. Appositional growth continues in the metaphysis because its blood supply remains intact or, at least, is less impaired. The resulting disturbance of the normal remodelling must lead to a short wide neck such as occurs in Legg-Perthes' disease. 2. Measurements were made of the length and width of the femoral neck on radiographs of forty patients with Legg-Perthes' disease. The results showed that the degree of shortening and widening is related to the extent of structural change in the head. 3. Repeated measurements in the early stages of the active disease may permit an early prognosis which may be of great assistance in selecting the treatment suitable to each patient. The financial assistance of the Ontario Society for Crippled Children is gratefully acknowledged

1. Serial slices of articular cartilage obtained at necropsy from apparently normal femoral condyles of individuals between the ages of twenty-six and sixty were examined chemically, by electron microscopy and for permeability. 2. The most superficial layer was shown by chemical analysis and electron microscopy to have the highest collagen content, which fell sharply with distance from the articular surface. On the other hand the glycosaminoglycan content was very low in the superficial layers but increased with depth. This variation was found in all specimens tested but the absolute levels of collagen and of glycosaminoglycans were widely different. There was no correlation of chemical composition with age. 3. Collagen fibrils in the superficial layer were of much smaller diameter than in the deeper zones. 4. Hydraulic permeability was shown to depend more on glycosaminoglycan than on collagen content, although it varied inversely with both these factors. 5. The results obtained demonstrate clearly the close relation between the physical properties of cartilage and its chemical composition

1. The three age types of acute haematogenous osteomyelitis are conditioned in their respective clinical features by the differing nature of their vascular bone pattern. 2. In the infant the condition causes severe and often permanent epiphysial damage and joint infection, a large involucrum but only transient damage to the shaft and metaphysis. 3. In the child the condition is responsible for extensive cortical damage with involucrum formation, but, except for some stimulation of growth, permanent damage to the growth cartilage and to joints is exceptional. Chronicity of the disease is rare if treatment has been effective. 4. In the adult acute osteomyelitis of the long bones is rare. It causes very frequent joint infection; the cortex is absorbed instead of sequestrating. The whole of the bone is invaded and frequently leaves chronic infection in the bone marrow. 5. The vascular characteristics of the bones in each age group and their relation to the onset of infection are described. 6. Some general directives for management based on these facts are suggested

Amputation or post-mortem specimens from eight cases of joint tuberculosis, with immobilisation changes in bone, have been studied by fine-detail slab radiographs and subsequent histological examination. The findings in three of these cases are presented in detail. The immobilisation changes take the form of a true osteoporosis, which is strikingly focal in nature. In the adult the sites of most marked involvement include the subcortical bone adjacent to articular surfaces and the bone in the neighbourhood of the obliterated epiphysial plates. Areas of permanent change in bone structure may result, although commencing "repair" is seen in the form of newly developed bone trabeculae in the osteoporotic areas. In one case, where immobilisation occurred at an early age, changes in the growing epiphysial plates were produced in addition to osteoporosis. This is correlated with the known susceptibility of growing epiphysial cartilage to a wide variety of damaging agents. Radiologically, it is important to discriminate between these immobilisation changes and the bone destruction which might be produced by extension of the tuberculous lesion itself

Three elderly sibling dwarfs are reported from a large and otherwise normal family. Their condition is an unusual and irregular form of cartilaginous defect, combined with club-feet, and bearing some resemblance to the Morquio type. A brief consideration of the literature of the generahised developmental bony syndromes shows confusion of thought and nomenclature. A plea is therefore made for simplification and a rational and simple grouping of these conditions is attempted. It seems particularly desirable that many confusing names for particular syndromes should be scrapped (for example, dyschondroplasia, chondro-osteodystrophy), although quite evidently the terms achondroplasia and osteogenesis imperfecta must remain because of their long-standing and general usage. Incidentally I have suggested elsewhere (Jackson 1951) that the name cleido-cranial dysostosis should be dropped, because it tends to lead the investigator away from the clinically more important lesions in the teeth and the cartilage bones of the pelvis and legs. It seems reasonable to confine the nomenclature of these various syndromes to the names used in the above classification, or something on those lines

Objectives

Bone fracture healing is regulated by a series of complex physicochemical and biochemical processes. One of these processes is bone mineralization, which is vital for normal bone development. Phosphatase, orphan 1 (PHOSPHO1), a skeletal tissue-specific phosphatase, has been shown to be involved in the mineralization of the extracellular matrix and to maintain the structural integrity of bone. In this study, we examined how PHOSPHO1 deficiency might affect the healing and quality of fracture callus in mice.

Aims

The aim of this study was to assess the influence of obesity on the clinical outcomes and survivorship ten years postoperatively in patients who underwent a fixed-bearing unicompartmental knee arthroplasty (UKA).

After a severe ankle sprain the incidence of residual complaints, particularly on the medial side of the joint, is high. We studied a consecutive series of 30 patients who had operative repair of acute ruptures of lateral ligaments. During operation, arthroscopy revealed a fresh injury to the articular cartilage in 20 ankles, in 19 at the tip and/or anterior distal part of the medial malleolus as well as on the opposite medial facet of the talus. In six patients, a loose piece of articular cartilage was found. We conclude that in patients with a rupture of one or more of the lateral ankle ligaments after an inversion injury, an impingement occurs between the medial malleolus and the medial facet of the talus. Patients with a lesion of the lateral ankle ligament caused by a high-velocity injury (a faulty landing during jumping or running) had a higher incidence of macroscopic cartilage damage (p < 0.01), medially-located pressure pain (p = 0.06) and medially-located complaints at one-year follow-up (p = 0.02) than those with a low-velocity injury (a stumble)

We compared the changes in the ratio of type-I and type-II collagen in monolayer cultures of human articular chondrocytes (HAC). HAC were isolated from samples of cartilage from normal joints and cultivated in monolayer for up to 46 days. Expression of collagen type-I and type-II was determined by immunocytochemistry, Western blotting, and the nested reverse transcription polymerase chain reaction (RT-PCR), and quantified by real-time PCR. The transition from a spherical morphology to the flattened morphology of an anchorage-dependent culture was accompanied by a rapid change in the collagen phenotype with the replacement of collagen type II by collagen type I. This was confirmed by immunocytochemistry and Western blotting between days 21 and 28. Using techniques for the analysis of gene transcription (nested RT-PCR and real-time PCR), a complete switch of collagen gene expression was not observed. Expression of collagen type I increased 100-fold during the culture time. That of collagen type II was found during the entire period and decreased more than 100-fold. The main finding was that expression of the genes encoding collagen type I and II was highly time-dependent and the ratio of collagen type II to I (CII/CI), defined as an index of cell differentiation, was significantly higher (215- to 480-fold) at the beginning of the culture. At the end of the experimental culture time, ratios between 0.1 and 1 were reached