Aims. The management of periprosthetic joint infection (PJI) remains a major challenge in orthopaedic surgery. In this study, we aimed to characterize the local bone microstructure and metabolism in a clinical cohort of patients with chronic PJI. Methods. Periprosthetic femoral trabecular bone specimens were obtained from patients suffering from chronic PJI of the hip and knee (n = 20). Microbiological analysis was performed on preoperative joint aspirates and tissue specimens obtained during revision surgery. Microstructural and cellular bone parameters were analyzed in bone specimens by histomorphometry on undecalcified sections complemented by tartrate-resistant acid phosphatase immunohistochemistry. Data were compared with control specimens obtained during primary arthroplasty (n = 20) and aseptic revision (n = 20). Results. PJI specimens exhibited a higher bone volume, thickened trabeculae, and increased osteoid parameters compared to both control groups, suggesting an accelerated bone turnover with sclerotic microstructure. On the cellular level, osteoblast and osteoclast parameters were markedly increased in the PJI cohort. Furthermore, a positive association between serum (CRP) but not synovial (white blood cell (WBC) count) inflammatory markers and osteoclast indices could be detected. Comparison between different pathogens revealed increased osteoclastic bone resorption parameters without a concomitant increase in osteoblasts in bone specimens from patients with Staphylococcus aureus infection, compared to those with detection of Staphylococcus epidermidis and Cutibacterium spp. Conclusion. This study provides insights into the local bone metabolism in chronic PJI, demonstrating osteosclerosis with high bone turnover. The fact that Staphylococcus aureus was associated with distinctly increased osteoclast indices strongly suggests early surgical treatment to prevent periprosthetic bone alterations. Cite this article: Bone Joint Res 2023;12(10):644–653

Aims. Venous tumour thrombus (VTT) is a rare finding in osteosarcoma. Despite the high rate of VTT in osteosarcoma of the pelvis, there are very few descriptions of VTT associated with extrapelvic primary osteosarcoma. We therefore sought to describe the prevalence and presenting features of VTT in osteosarcoma of both the pelvis and the limbs. Methods. Records from a single institution were retrospectively reviewed for 308 patients with osteosarcoma of the pelvis or limb treated between January 2000 and December 2022. Primary lesions were located in an upper limb (n = 40), lower limb (n = 198), or pelvis (n = 70). Preoperative imaging and operative reports were reviewed to identify patients with thrombi in proximity to their primary lesion. Imaging and histopathology were used to determine presence of tumour within the thrombus. Results. Tumours abutted the blood vessels in 131 patients (43%) and encased the vessels in 30 (10%). Any form of venous thrombus was identified in 31 patients (10%). Overall, 21 of these thrombi were determined to be involved with the tumour based on imaging (n = 9) or histopathology (n = 12). The rate of VTT was 25% for pelvic osteosarcoma and 1.7% for limb osteosarcoma. The most common imaging features associated with histopathologically proven VTT were enhancement with contrast (n = 12; 100%), venous enlargement (n = 10; 83%), vessel encasement (n = 8; 66%), and visible intraluminal osteoid matrix (n = 6; 50%). Disease-specific survival (DSS) for patients with VTT was 95% at 12 months (95% CI 0.87 to 1.00), 50% at three years (95% CI 0.31 to 0.80), and 31% at five years (95% CI 0.14 to 0.71). VTT was associated with worse DSS (hazard ratio 2.3 (95% CI 1.11 to 4.84). Conclusion. VTT is rare with osteosarcoma and occurs more commonly in the pelvis than the limbs. Imaging features suggestive of VTT include enhancement with contrast, venous dilation, and vessel encasement. VTT portends a worse prognosis for patients with osteosarcoma, with a similar survivability to metastatic disease. Cite this article: Bone Joint J 2024;106-B(8):865–870

We describe 100 consecutive patients with osteoid osteoma. Of the 97 who had operations, 89 were treated by intralesional excision and eight by wide resection. The three remaining patients were not operated on because the osteoid osteoma was almost painless, or was found in the pedicle of the 12th thoracic vertebra at the site of entrance of the artery of Adamkjewicz. The diagnosis was confirmed histologically in all specimens. No local recurrences were observed at a minimum follow-up of one year. All except one patient were mobilised two to four days after surgery. A precise preoperative diagnosis of the lesion is mandatory, based on clinical findings, standard radiographs, thin-section CT and a bone scan. We compared our operative technique with 247 cases in which the percutaneous technique of removal or coagulation of the nidus had been performed. The latter procedure has a less constant rate of primary cure (83% v 100%). Its principal indication appears to be for osteoid osteomas in the proximal femur and the pelvis

1. A case of osteoid osteoma of the skull is reported, with characteristic clinical, radiological and pathological features. 2. Osteoid osteoma of the skull has not previously been reported

Subperiosteal osteoid osteoma in a juxta-articular site presents a diagnostic challenge. The clinical features of joint stiffness, synovitis, muscle atrophy and local warmth may suggest arthritis rather than osteoid osteoma, while radiographs, bone scans and angiograms may not be diagnostic. We describe four cases of this rare condition

A case of intracortical haemangioma in the tibial diaphysis is reported. The radiological and macroscopic features were identical with osteoid osteoma. In view of this similarity, haemangiomata, despite their rarity at this site, must be considered in the differential diagnosis of osteoid osteoma

We treated 58 patients with osteoid osteoma by CT-guided radiofrequency ablation (RF). In 16 it followed one or two unsuccessful open procedures. It was performed under general anaesthesia in 48, and spinal anaesthesia in ten. The nidus was first located by thin-cut CT (2 to 3 mm) sections. In hard bony areas a 2 mm coaxial drill system was applied. In softer areas an 11-gauge Jamshidi needle was inserted to allow the passage of a 1 mm RF probe into the centre of the nidus. RF ablation was administered at 90°C for a period of four to five minutes. Three patients had recurrence of pain three, five and seven months after treatment, respectively, and a second percutaneous procedure was successful. Thus, the primary rate of success for all patients was 95% and the secondary rate was 100%. One minor complication was encountered. CT-guided RF ablation is a safe, simple and effective method of treatment for osteoid osteoma

1. Specimens are described in which osteoid was seen in undecalcified bone sections prepared from a number of osteoarthritic femoral heads. 2. It was localised mostly in the pressure segments. 3. The reason for the presence of this osteoid is not well understood and the possibilities of local histochemical changes and/or cellular metaplasia are discussed

1. Three cases of a benign osteoblastic lesion of bone are described. An outstanding feature of each was the hyperostosis of adjacent bones or synovitis in an adjacent joint. 2. The clinical, radiological and histological features resembled osteoid osteomata more than benign osteoblastoma in each case. 3. The significance of this observation is questioned in relation to the pathogenesis of osteoid osteoma

1. A case of an osteoid osteoma in the terminal phalanx of a finger is recorded. 2. Unusual features were enlargement of the finger with nail hypertrophy, sweating, and premature fusion of the epiphysis

1. Two cases of osteoid osteoma of the vertebrae are presented. 2. The unusual clinical histories and findings are reported in detail

1. A case of osteoid osteoma which recurred twice after block excision is reported. 2. It is postulated that recurrence is almost certainly caused by incomplete removal of the nidus, either by curettage or by incomplete block excision. 3. Why curettage is successful in most cases but not in others is obscure, but it may be that the arterial supply to the tumour is interrupted. 4. Block excision with adequate radiographic control to ensure its completeness is the treatment of choice

We treated 106 patients with a peripheral osteoid osteoma by conventional surgical methods; 81 had curettage and 25 en-bloc resection. The rate of local recurrence after curettage was 12% and after en-bloc resection 4.5%. Postoperative fractures were observed in 3% after curettage and in 4.5% after en-bloc resection. We compared our findings with those reported in the literature after minimally invasive treatment and concluded that curettage can be regarded as the treatment of choice in patients in whom minimally invasive methods do not offer any advantage, for example, for subperiosteal tumours which are readily accessible, or when the diagnosis is unclear and further histological analysis is required

1. The clinical features in twenty cases of osteoid osteoma have been analysed and compared with other cases reported in the literature. 2. The lesion is regarded as a benign neoplasm and its unusual clinical behaviour is attributed to its vascular nature. 3. The frequency with which an erroneous diagnosis of "neurosis" is made is stressed

Seven patients with osteoid osteoma of the proximal femur were treated by percutaneous excision of the nidus. The combination of preoperative localisation by tomography and intraoperative localisation by image intensifier resulted in a curative procedure with minimal bone resection in all cases, although a second operation was required in one patient

We report the results of a prospective study of 23 patients in which interstitial laser photocoagulation (ILP) was used to treat an osteoid osteoma. ILP is a technique in which tumour tissue is destroyed by direct heating using low-power laser light energy delivered by thin (400 μm) optical fibres which are introduced percutaneously into the tumour under image guidance. Pain was evaluated before operation and at the latest follow-up using a visual analogue scale with 0 denoting no pain and 10 the worst pain imaginable. The mean follow-up was for 15 months. The results showed that the mean pain score decreased from 7.5 before operation to 0.95 at the latest follow-up. Fourteen patients had no pain and eight had minor discomfort, not requiring analgesia. One patient required a second procedure because placement of the fibre had not been accurate enough and one developed recurrent symptoms eight months after treatment. All patients were satisfied with the operation because of the rapid resolution of pain, the minimally invasive nature of the procedure, and the fact that there was no postoperative restriction of activity

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

The behaviour pattern of the scoliosis associated with osteoid osteoma or osteoblastoma of the spine is described. In patients presenting with symptoms at or around skeletal maturity, the scoliosis is postural. Excision of the lesion ensures complete resolution of the curve. In the growing child, however, an initial postural scoliosis may develop vertebral rotation with structural characteristics. The magnitude of the curve and the associated vertebral rotation is dependent on the time interval between the onset of symptoms and the surgical treatment. Although removal of the lesion usually results in regression of the curve, a prolonged delay in treatment may result in a progressive structural scoliosis. A possible mechanism for the behaviour of the scoliosis is discussed

The clinical presentation and treatment of 18 cases of osteoid osteoma or osteoblastoma of the spine are described, with an average follow-up of 4.2 years (range three months to 11.5 years). The average delay between the onset of symptoms and definitive diagnosis was 19 months. All patients presented with marked spinal stiffness and a painful scoliosis. The lesion was situated in the pedicle in the 15 patients with involvement of the thoracolumbar spine. A surgical approach allowing direct access to the pedicle without entering the spinal canal or jeopardising spinal stability is described. Surgical treatment afforded immediate relief of pain and an early return of full spinal mobility

Osteoid osteoma is treated primarily by radiofrequency (RF) ablation. However, there is little information about the distribution of heat in bone during the procedure and its safety. We constructed a model of osteoid osteoma to assess the distribution of heat in bone and to define the margins of safety for ablation. Cavities were drilled in cadaver bovine bones and filled with a liver homogenate to simulate the tumour matrix. Temperature-sensing probes were placed in the bone in a radial fashion away from the cavities. RF ablation was performed 107 times in tumours < 10 mm in diameter (72 of which were in cortical bone, 35 in cancellous bone), and 41 times in cortical bone with models > 10 mm in diameter. Significantly higher temperatures were found in cancellous bone than in cortical bone (p <  0.05). For lesions up to 10 mm in diameter, in both bone types, the temperature varied directly with the size of the tumour (p < 0.05), and inversely with the distance from it. Tumours of > 10 mm in diameter showed a trend similar to those of smaller lesions. No temperature rise was seen beyond 12 mm from the edge of a cortical tumour of any size. Formulae were developed to predict the expected temperature in the bone during ablation. Cite this article: Bone Joint J 2014; 96-B:677–83

Objectives. Experimental studies indicate that non-steroidal anti-inflammatory drugs (NSAIDs) may have negative effects on fracture healing. This study aimed to assess the effect of immediate and delayed short-term administration of clinically relevant parecoxib doses and timing on fracture healing using an established animal fracture model. Methods. A standardized closed tibia shaft fracture was induced and stabilized by reamed intramedullary nailing in 66 Wistar rats. A ‘parecoxib immediate’ (Pi) group received parecoxib (3.2 mg/kg bodyweight twice per day) on days 0, 1, and 2. A ‘parecoxib delayed’ (Pd) group received the same dose of parecoxib on days 3, 4, and 5. A control group received saline only. Fracture healing was evaluated by biomechanical tests, histomorphometry, and dual-energy x-ray absorptiometry (DXA) at four weeks. Results. For ultimate bending moment, the median ratio between fractured and non-fractured tibia was 0.61 (interquartile range (IQR) 0.45 to 0.82) in the Pi group, 0.44 (IQR 0.42 to 0.52) in the Pd group, and 0.50 (IQR 0.41 to 0.75) in the control group (n = 44; p = 0.068). There were no differences between the groups for stiffness, energy, deflection, callus diameter, DXA measurements (n = 64), histomorphometrically osteoid/bone ratio, or callus area (n = 20). Conclusion. This study demonstrates no negative effect of immediate or delayed short-term administration of parecoxib on diaphyseal fracture healing in rats. Cite this article: G. A. Hjorthaug, E. Søreide, L. Nordsletten, J. E. Madsen, F. P. Reinholt, S. Niratisairak, S. Dimmen. Short-term perioperative parecoxib is not detrimental to shaft fracture healing in a rat model. Bone Joint Res 2019;8:472–480. DOI: 10.1302/2046-3758.810.BJR-2018-0341.R1

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. Methods. Tibial fractures were created and then stabilized in control wild-type (WT) and Phospho1. -/-. mice (n = 16 for each group; mixed gender, each group carrying equal number of male and female mice) at eight weeks of age. Fractures were allowed to heal for four weeks and then the mice were euthanized and their tibias analyzed using radiographs, micro-CT (μCT), histology, histomorphometry and three-point bending tests. Results. The μCT and radiographic analyses revealed a mild reduction of bone volume in Phospho1. -/-. callus, although it was not statistically significant. An increase in trabecular number and a decrease in trabecular thickness and separation were observed in Phospho1. -/-. callus in comparison with the WT callus. Histomorphometric analyses showed that there was a marked increase of osteoid volume over bone volume in the Phospho1. -/-. callus. The three-point bending test showed that Phospho1. -/-. fractured bone had more of an elastic characteristic than the WT bone. Conclusion. Our work suggests that PHOSPHO1 plays an integral role during bone fracture repair and may be a therapeutic target to improve the fracture healing process. Cite this article: M. W. Morcos, H. Al-Jallad, J. Li, C. Farquharson, J. L. Millán, R. C. Hamdy, M. Murshed. PHOSPHO1 is essential for normal bone fracture healing: An Animal Study. Bone Joint Res 2018;7:397–405. DOI: 10.1302/2046-3758.76.BJR-2017-0140.R2

The role of three genetically distinct collagen types in the formation of endochondral bone and in calcification and resorption of cartilage has been assessed. Using antibodies specific to types I, II and III collagen we have demonstrated in the embryonic chick tibia that endochondral bone formation began with deposition of type III collagen in lacunae of hypertropic chondrocytes by invading bone-marrow-derived cells. This was followed by the deposition of type I collagen, which is the collagenous constituent of endochondral osteoid. At later stages of development endochondral osteoid was found in the epiphysial growth plate in apparently intact lacunae of hypertrophic chondrocytes; this indicated that the latter might contribute to the synthesis of osteoid type I collagen. Immuno-histological staining for collagen types, and von Kossa staining for calcium phosphate on parallel sections, demonstrated that type I and type II collagen matrices were substrates for calcification. Endochondral bone (with type I collagen) was found on scaffolding of both uncalcified and calcified cartilage (with type II collagen), indicating that calcification of endochondral osteoid and of the underlying cartilage occurred independentyl. Spicules of endochondral cancellous bone of a four-week-old chick contained a core of calcified type II collagen

When large daily doses of vitamin D were administered to rats endochondral growth was inhibited and bone resorption occurred; later in the process uncalcified matrix (osteoid) like that seen in rickets formed on trabecular margins. When vitamin D was given only for a short period and then discontinued, little resorption of bone was seen during the withdrawal period and wide seams of osteoid material appeared which eventually calcified in an irregular manner. When normal endochondral growth was resumed a wide transverse band of dense bone with enclosed cartilaginous cores was left in the marrow cavity. If, after a few days, a second large dose of the vitamin was given resorption again occurred and calcification of osteoid material was accelerated, the first microscopic sign being a dense, wide, granular, deeply staining line at the junction of the bone and new osteoid. After a second withdrawal period a second layer of osteoid formed; eventually another transverse band appeared in the metaphysis. If this hypervitaminosis D cycle (+4 -12) was continued rats continued to form new bone with relatively little remodelling, so that after three such cycles bones became dense and hard. Histological study showed that little marrow cavity remained in either skull, vertebrae or epiphyses and a dense mass of bone enclosing cartilage cores filled the metaphysial part of the long bones. In addition, ankylosis ofteeth, calcification of spinal ligaments and widespread metastatic calcification were present. When hypervitaminosis D cycles (+1 -12, +1 -21) were adjusted to produce minimal resorptive changes a wide range of bone change was observed. This varied from uniform dense metaphysial bone containing abnormal cartilage matrix arranged in longitudinal striations, dense transverse bands parallel to the epiphysial cartilage, to remnants of dense trabeculae extending into the marrow cavity. Bone changes in osteopetrosis structurally closely resembled the induced bone changes in the rat. It is concluded that an important mechanism in the production of osteopetrosis is an accentuated rhythm of bone change like that shown experimentally to be produced in these animals. It is emphasised that these changes are but part of a range of bone disorders associated with abnormalities of cycles of resorption and deposition of bone, the type of change differing with the nature of the cycles

The February 2013 Oncology Roundup. 360 . looks at: proximal fibular tumours; radiotherapy-induced chondrosarcoma; mega-prosthesis; CRP predictions of sarcoma survival; predicting survival in metastatic disease; MRI for recurrence in osteoid osteoma; and a sarcoma refresher

Continuous strontium administration first induces typical "rickets" in young rats receiving adequate calcium phosphorus and vitamin D but later the widened cartilage spontaneously calcifies intermittently leaving transverse bands consisting largely of osteoid tissue in the metaphysis; in addition to intermittent calcification bone changes indicate that skeletal growth is not uniformly progressive. Subsequently areas of the epiphysial cartilage fail to calcify and localised defects develop; among these are wedge-shaped metaphysial osteoid tissue masses, "invagination" of the epiphysial plate to form multiple nodules of cartilage with proliferating cells in the middle and hypertrophic ones at the periphery, perforation and fragmentation of the epiphysial plate with formation of large cartilage nodules. Multiple cartilage nodules of different sizes appear in the epiphysis, metaphysis and bone shaft. Most bone margins are lined by osteoid seams which only slowly calcify and concomitantly resorption is decreased so that the rate of remodelling of the skeleton is diminished. This type of process may help to explain the results of treatment of osteoporosis by strontium administration

Vancomycin-supplemented allografts provide biological restoration of bone stock and sound fixation with a low incidence of re-infection. Experimental incorporation of these grafts is similar to allografts without vancomycin. However, the underlying biology remains unknown. We report the first histological observations of vancomycin-supplemented impacted bone allografts in two reconstructions performed 14 and 20 months after revision surgery because of a periprosthetic fracture. Areas of active bone remodelling (creeping substitution), as well as calcified bone trabeculae and graft particles embedded in dense fibrous tissue, were observed with osteoid and fibroconnective tissue surrounding polymethylmethacrylate particles. These pathological findings are similar to those reported in allografts without vancomycin and support the hypothesis that high levels of vancomycin do not affect the incorporation of bone graft

Osteoarthritis (OA) is mainly caused by ageing, strain, trauma, and congenital joint abnormalities, resulting in articular cartilage degeneration. During the pathogenesis of OA, the changes in subchondral bone (SB) are not only secondary manifestations of OA, but also an active part of the disease, and are closely associated with the severity of OA. In different stages of OA, there were microstructural changes in SB. Osteocytes, osteoblasts, and osteoclasts in SB are important in the pathogenesis of OA. The signal transduction mechanism in SB is necessary to maintain the balance of a stable phenotype, extracellular matrix (ECM) synthesis, and bone remodelling between articular cartilage and SB. An imbalance in signal transduction can lead to reduced cartilage quality and SB thickening, which leads to the progression of OA. By understanding changes in SB in OA, researchers are exploring drugs that can regulate these changes, which will help to provide new ideas for the treatment of OA.

Cite this article: Bone Joint Res 2023;12(9):536–545.

1. Regional osteoporosis is a common finding in osteoid osteoma. It may in fact be a constant feature because it was present in all the patients reported in this paper and was suspected in others who have not been included in this report because of insufficient information. 2. Five of our six cases showed osteoporosis about the hip. Osteoporosis is more likely to be noticed in this region than in other parts of the extremities because both hips are usually radiographed on one film. We have seen several instances in which we suspected generalised osteoporosis of an extremity but Case 5 was the only one in which comparable radiographs had been taken of both feet. 3. When there is osteoporosis in the region of a joint with symptoms referred to that joint an osteoid osteoma may be the cause. The nidus may lie at some distance from the joint surfaces and may not be seen in standard radiographs of the joint (Case 4). Additional radiographs including a wider area than usual may be necessary to show the lesion, and tomography is sometimes required

Metal meshes are used in revision surgery of the hip to contain impacted bone grafts in cases with cortical or calcar defects in order to provide rotational stability to the stem. However, the viability of bone allografts under these metal meshes has been uncertain. We describe the histological appearances of biopsies obtained from impacted bone allografts to the calcar contained by a metal mesh in two femoral reconstructions which needed further surgery at 24 and 33 months after the revision procedure. A line of osteoid and viable new bone was observed on the surface of necrotic trabeculae. Active bone marrow between these trabeculae showed necrotic areas in some medullary spaces with reparative fibrous tissue and isolated reactive lymphocytes. This is interpreted as reparative changes after revascularisation of the cancellous allografts. These pathological findings are similar to those reported in allografts contained by cortical host bone and support the hypothesis that incorporation of morcellised bone under metal meshes is not affected by these devices

1. Four cases of osteomalacia secondary to vitamin D deficiency have been investigated histologically and with the electron microscope. 2. Three main types of cells were found along the osteoid tissue. Cells of Group 1 are like normal osteoblasts, except that their cytoplasm has an ordered granular endoplasmic reticulum, without enlarged cysternae. Moreover, it contains isolated rosettes of glycogen. Cells of Group 2 are like young progenitor cells. There are almost no rough cysternae in the cytoplasm. This contains clusters of glycogen, isolated ribosomes and many mitochondria. Cells of Group 3 are structurally like "resting" flat osteoblasts in normal bone. 3. The paper discusses how the presence of the three groups may be related to vitamin D deficiency or secondary hyperparathyroidism. 4. Malacic osteoid tissue consists of apparently normal collagen fibrils. Both optical and electron microscopy show that this tissue can calcify. But calcification stops at an early stage, or proceeds much more slowly than normal. So large areas ofosteoid tissue are left uncalcified. 5. Calcium salts are laid down either as needle-shaped crystals exactly like those in normal bone, or else abnormally. Where abnormal they either appear in a finely granular, almost amorphous form, or else acquire a characteristic star-like crystalline structure. 6. Where calcification takes place bundles of laterally aggregated collagen fibrils are found

1. A description is given of the pathology of a generalised skeletal disease characterised by a defect in the formation of the collagen fibres of the bone matrix—"fibrogenesis imperfecta ossium.". 2. Material from two cases, a woman of fifty-six and a man of sixty-four, was examined. All the samples of bone from both patients showed the same defect, which was severe in most of the specimens, and there was radiographic evidence of similar widespread bone changes in both cases. 3. The defect is clear-cut and striking histologically, provided that sections are examined with a polarising microscope, and/or by reticulin methods. 4. As a result of the defect in the bone matrix this fails to calcify, or calcifies imperfectly, showing wide osteoid borders as in severe osteomalacia. But the fibre defect separates it quite clearly from osteomalacia, in which the fibre structure of the osteoid tissue is normal. Moreover neither the biochemical findings (Case 2) nor the radiographic appearances correspond with those of osteomalacia. 5. The collagen fibre defect is confined to the bone matrix; no defect was found in the soft tissue collagen, and even the periosteum shows a normal fibre structure. 6. Both the clinical and the histological evidence indicate that the disease is not congenital, but was, in these two patients, apparently acquired during middle age. There was no family history of bone disease. 7. The cause of the condition is quite obscure. It is not inflammatory or neoplastic, nor is there histological or clinical evidence of a toxic origin. If it is a deficiency disease it is unlike any known vitamin or other chemical deficiency

Aims

The aim of this study is to determine the predictors of overall survival (OS) and predictive factors of poor prognosis of conventional high-grade osteosarcoma of the limbs in a single-centre in South Africa.

Aims

Low-grade central osteosarcoma (LGCOS), a rare type of osteosarcoma, often has misleading radiological and pathological features that overlap with those of other bone tumours, thereby complicating diagnosis and treatment. We aimed to analyze the clinical, radiological, and pathological features of patients with LGCOS, with a focus on diagnosis, treatment, and outcomes.

Aims

Distraction osteogenesis (DO) is a useful orthopaedic procedure employed to lengthen and reshape bones by stimulating bone formation through controlled slow stretching force. Despite its promising applications, difficulties are still encountered. Our previous study demonstrated that pulsed electromagnetic field (PEMF) treatment significantly enhances bone mineralization and neovascularization, suggesting its potential application. The current study compared a new, high slew rate (HSR) PEMF signal, with different treatment durations, with the standard Food and Drug Administration (FDA)-approved signal, to determine if HSR PEMF is a better alternative for bone formation augmentation.

Aims

The aims of this study were to determine the diagnostic yield of image-guided biopsy in providing a final diagnosis in patients with suspected infectious spondylodiscitis, to report the diagnostic accuracy of various microbiological tests and histological examinations in these patients, and to report the epidemiology of infectious spondylodiscitis from a country where tuberculosis (TB) is endemic, including the incidence of drug-resistant TB.

Two cases of benign osteoblastic tumours of the spine, occurring in young patients, and presenting as expanding osteolytic lesions with some central calcification and ossification, are described. It is suggested that they represent a condition allied to, but usefully separated from, osteoid osteoma of bone. The name osteogenic fibroma of bone, proposed by Lichtenstein for this type of case, is accepted

1. Fluorotic bones and exostoses obtained from the skeletons of two subjects with advanced fluorosis have been examined microscopically. 2. The cortical bone showed normal, regular Haversian systems with normal canaliculi and lacunae. The exostoses also exhibited normal, regular Haversian systems but at places the reabsorption tunnels were large. 3. Special stains failed to show osteoid tissue either in the fluorotic bones or in their exostoses

Radiopharmaceuticals have been successfully used to detect occult neoplasms and infective lesions. Bone scans using 99mTc-labelled methylene diphosphonate located osteoid osteomas accurately in a series of 30 symptomatic patients. A portable radiation detector system has been designed to help intra-operative localisation and facilitate complete excision of the lesions with minimal damage to normal tissue. A sodium iodide detector with a fibre-optic link was used at first, but a cadmium telluride system has provided a more durable, reliable and sensitive sterilisable probe

We treated 13 children with histologically confirmed cystic tuberculosis of bone. Ten had solitary cystic lesions and three had the multicystic form. Signs and symptoms were related mainly to the joint adjacent to the cyst. Most lesions were in the metaphyses of long bones. They were radiolucent, round or oval, and resembled pyogenic infections, aneurysmal and simple bone cysts, cartilaginous tumours or osteoid osteoma. Only two of the children had pulmonary tuberculosis. The Mantoux skin test was negative in four children and the ESR was normal in five. Curettage followed by anti-tuberculosis therapy for one year resulted in good healing, but two children had residual joint contractures. Biopsy should be taken from the cystic area rather than from the synovium when a joint is involved

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

The features are described of seven cases of "juxtacortical" chondrosarcoma, the term introduced by Jaffe for a rare but distinct entity and now accepted in the World Health Organisation classification as preferable to the term "periosteal" chondrosarcoma. In all cases the lesion involved the shaft of a long bone, most often the femur, and in two cases two different long bones were affected. Six of the seven patients were male and all were in the second decade. The characteristic appearance was that of a small tumour adjacent to the cortex with areas of spotty calcification often accompanied by radiating bone spicules perpendicular to the bone shaft and a typical Codman's triangle. Histologically all the tumours showed a cartilaginous lobular pattern, well limited on the surface and seldom infiltrating the cortex; areas of spotty calcification and enchondral ossification were often present but tumour osteoid and bone were conspicuously absent. Despite the ominous histological aspect, the prognosis proved to be relatively favourable compared with the usual central chondrosarcoma of a similar grade of malignancy

Migration of 65 Charnley stems implanted with modern cementing techniques was studied by roentgen stereophotogrammetry. There were 25 patients with rheumatoid arthritis (RA) and 40 with osteoarthritis (OA) followed up for two years. In 43 cases a bone sample for histomorphometric analysis was obtained from the femur during the operation. In 22 cases the mean subsidence of the prosthetic head was 0.40 mm and in 20 the mean posterior migration was 1.25 mm. There was no difference in migration between the two diagnostic groups (p = 0.8) after adjusting for variations in gender, age and weight. Male gender was associated with increased subsidence (p = 0.006). Histological examination showed that the RA series had more osteoid surface (p = 0.04), but neither this, nor any of the other histomorphometric variables, influenced migration. These results suggest that, unlike the acetabular socket, the cemented Charnley femoral component is equally secure in osteoarthritis and in rheumatoid arthritis, and that its initial fixation is not influenced by the quality of the local cancellous bone. Our results provide data with which the early performance of new prosthetic designs and fixation methods can be compared

1. The technique of compression-arthrodesis of the knee joint is described. 2. Fifteen consecutive cases are reported in which clinical union was detected at the first inspection from twelve days to six weeks after operation. By this method the total period of disability is reduced to three months. 3. Three mechanical factors which might be responsible for this very early clinical union are examined: compression is believed to be the main factor, although fixation is also important. 4. A fallacy is exposed in the use of bone grafts for arthrodesis of the knee; the graft is less osteogenic than the substance of the bones which form the joint, and it provides inefficient internal fixation. 5. A theory is suggested that compression, even in the presence of slight movement, acts by producing a fixed "hinge" without shearing movement; at this point a bridgehead of flexible osteoid tissue is established in which ossification inevitably takes place despite slight bending movement. 6. A second theory is suggested that high compression forces stimulate early union by liberating bone salts at points of maximum pressure through the action of osteoclasts, and that the local excess of bone salts is redeposited under cellular activity within a range of a few millimetres where there is no pressure

Skeletal scintigraphy, which has now been established as a useful and accurate method of detecting early skeletal metastases and assessing their response to treatment, has been investigated for its pathological basis. Histological examination of several hundred necropsy specimens, from sixty-eight patients who died from malignant disease, showed a significant increase of osteoid and immature woven bone in the presence of metastatic cancer. Tumour-cell suspensions of the VX2 carcinoma were injected into the medullary cavity or on to the periosteal surface of the ilia or tibiae of New Zealand white rabbits. A combination of bone destruction and new bone formation, similar to the autopsy material, was seen. There were at least two mechanisms for the new bone production. Initially, intramembranous ossification was seen in the fibrous stroma surrounding the tumour. Once the cortex was involved and cortical bone destruction had occurred, large amounts of woven bone resembling fracture callus were laid down. The new bone had a markedly increased avidity for boneseeking isotopes, indicating why skeletal scintigraphy was useful. A further twenty rabbits, in whose ilia the VX2 carcinoma was growing, were treated by local irradiation. When treatment was successful the tumour was destroyed, the production of new bone ceased, and the lesion lost its increased avidity for bone-seeking isotopes, indicating that skeletal scintigraphy could be used to assess the response of skeletal metastases to therapy

1. Stable strontium in large amount in the diet of rats initially inhibits calcification and induces rickets. 2. Changes later become atypical and a complex series of epiphysial plate defects develops: formation of localised osteoid wedges in the metaphysis; invagination of the epiphysial plate and sequestration of multiple cartilage nodules into the marrow cavity; and, in severely affected animals, localised loss of part or parts of the epiphysial plate with formation of large cartilage nodules in the metaphysis and epiphysis. 3. The appearance of cartilage nodules in the metaphysis in man has been shown to be associated with changes in the epiphysial plate, but much of the information is radiological and therefore incomplete, and detailed cellular changes are seldom available. 4. Some of the conditions mentioned, which have presented difficulty in interpretation, partly because of their rarity but also because of lack of knowledge of the fundamental processes concerned, are multiple exostoses and endochondromatoses, metaphysial dysostosis and osteochondritis. 5. Comparison of basic mechanisms revealed in this study with those supposed to occur in human cartilage dystrophies demonstrates that strontium rickets mimics some changes occurring in chronic renal rickets; that invagination of the epiphysial plate and cartilage nodule sequestration could account for the development of multiple exostoses and some endochondromatoses; and that localised endochondral defects in calcification can induce epiphysial changes resembling osteochondritis juvenilis, demonstrating that avascular necrosis is not necessarily the mechanism initiating epiphysial deformity