Aims

This study aimed to investigate the effect of solute carrier family 20 member 2 (SLC20A2) gene mutation (identified from a hereditary multiple exostoses family) on chondrocyte proliferation and differentiation.

Tibial nonunion represents a spectrum of conditions which are challenging to treat, and optimal management remains unclear despite its high rate of incidence. We present 44 consecutive patients with 46 stiff tibial nonunions, treated with hexapod external fixators and distraction to achieve union and gradual deformity correction. There were 31 men and 13 women with a mean age of 35 years (18 to 68) and a mean follow-up of 12 months (6 to 40). No tibial osteotomies or bone graft procedures were performed. Bony union was achieved after the initial surgery in 41 (89.1%) tibias. Four persistent nonunions united after repeat treatment with closed hexapod distraction, resulting in bony union in 45 (97.8%) patients. The mean time to union was 23 weeks (11 to 49). Leg-length was restored to within 1 cm of the contralateral side in all tibias. Mechanical alignment was restored to within 5° of normal in 42 (91.3%) tibias. Closed distraction of stiff tibial nonunions can predictably lead to union without further surgery or bone graft. In addition to generating the required distraction to achieve union, hexapod circular external fixators can accurately correct concurrent deformities and limb-length discrepancies.

Cite this article: Bone Joint J 2015;97-B:1417–22.

This review is aimed at clinicians appraising preclinical trauma studies and researchers investigating compromised bone healing or novel treatments for fractures. It categorises the clinical scenarios of poor healing of fractures and attempts to match them with the appropriate animal models in the literature.

We performed an extensive literature search of animal models of long bone fracture repair/nonunion and grouped the resulting studies according to the clinical scenario they were attempting to reflect; we then scrutinised them for their reliability and accuracy in reproducing that clinical scenario.

Models for normal fracture repair (primary and secondary), delayed union, nonunion (atrophic and hypertrophic), segmental defects and fractures at risk of impaired healing were identified. Their accuracy in reflecting the clinical scenario ranged greatly and the reliability of reproducing the scenario ranged from 100% to 40%.

It is vital to know the limitations and success of each model when considering its application.

Aims. The aim of our study is to investigate the effect induced by alternated mechanical loading on Notch-1 in mandibular condylar cartilage (MCC) of growing rabbits. Methods. A total of 64 ten-day-old rabbits were randomly divided into two groups according to dietary hardness: normal diet group (pellet) and soft diet group (powder). In each group, the rabbits were further divided into four subgroups by feeding time: two weeks, four weeks, six weeks, and eight weeks. Animals would be injected 5-bromo-2′-deoxyuridine (BrdU) every day for one week before sacrificing. Histomorphometric analysis of MCC thickness was performed through haematoxylin and eosin (HE) staining. Immunochemical analysis was done to test BrdU and Notch-1. The quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used to measure expression of Notch-1, Jagged-1, and Delta-like 1 (Dll-1). Results. The thickness of MCC in the soft diet group was thinner than the one in normal diet group. Notch-1 was restricted in fibrous layer, proliferative layer, and hypertrophic layer. The expression of Notch-1 increased from two weeks to six weeks and then fell down. Notch-1 in normal diet group was higher than that in soft diet group in anterior part of MCC. The statistical differences of Notch-1 were shown at two, four, and six weeks (p < 0.05). The result of western blot and quantitative real-time PCR (qRT-PCR) showed the expression of Dll-1 and Jagged-1 rose from two to four weeks and started to decrease at four weeks. BrdU distributed in all layers of cartilage and subchondral bone. The number of BrdU-positive cells, which were less in soft diet group, was decreasing along with the experiment period. The significant difference was found at four, six, and eight weeks in anterior and posterior parts (p < 0.05). Conclusion. The structure and proliferation of MCC in rabbits were sensitive to dietary loading changes. The proper mechanical loading was essential for transduction of Notch signalling pathway and development of mandibular condylar cartilage. Cite this article: Bone Joint Res 2021;10(7):437–444

Growth plates taken from five- to 20-week-old Japanese white rabbits were immunostained for c-Myc protein. This was localised both in the proliferating zone and upper hypertrophic zone at five weeks, whereas after ten weeks it was found mostly in the lower hypertrophic zone. The proliferating chondrocytes tended to show nuclear staining and the hypertrophic cells cytoplasmic staining, although the terminal hypertrophic chondrocytes sometimes expressed the protein in their nuclei. In the younger rabbits, c-Myc co-localised with proliferating cell nuclear antigen, whereas in the hypertrophic zone of older rabbits, it was present in some chondrocytes the nuclei of which also contained DNA breaks. Our study suggests that, in the rabbit growth plate, c-Myc is associated with different cellular processes, depending on the age and the developmental stage of the chondrocytes

The December 2015 Trauma Roundup. 360 . looks at: Delay to surgery in hip fracture; Hexapod fixators in the management of hypertrophic tibial nonunions; Thromboembolism after nailing pathological fractures; Tibial plateau fracture patterns under the spotlight; The health economic effects of long bone nonunion; Adverse outcomes in trauma; The sacral screw in children; Treating the contralateral SUFE

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by progressive cartilage degradation, synovial membrane inflammation, osteophyte formation, and subchondral bone sclerosis. Pathological changes in cartilage and subchondral bone are the main processes in OA. In recent decades, many studies have demonstrated that activin-like kinase 3 (ALK3), a bone morphogenetic protein receptor, is essential for cartilage formation, osteogenesis, and postnatal skeletal development. Although the role of bone morphogenetic protein (BMP) signalling in articular cartilage and bone has been extensively studied, many new discoveries have been made in recent years around ALK3 targets in articular cartilage, subchondral bone, and the interaction between the two, broadening the original knowledge of the relationship between ALK3 and OA. In this review, we focus on the roles of ALK3 in OA, including cartilage and subchondral bone and related cells. It may be helpful to seek more efficient drugs or treatments for OA based on ALK3 signalling in future.

A 30-year-old man presented with pain and limitation of movement of the right hip. The symptoms had failed to respond to conservative treatment. Radiographs and CT scans revealed evidence of impingement between the femoral head-neck junction and an abnormally large anterior inferior iliac spine. Resection of the hypertrophic anterior inferior iliac spine was performed which produced full painless restoration of function of the hip. Hypertrophy of the anterior inferior iliac spine as a cause of femoro-acetabular impingement has not previously been described

Aims

Alcoholism is a well-known detrimental factor in fracture healing. However, the underlying mechanism of alcohol-inhibited fracture healing remains poorly understood.

Aims

Autologous chondrocyte implantation (ACI) is a promising treatment for articular cartilage degeneration and injury; however, it requires a large number of human hyaline chondrocytes, which often undergo dedifferentiation during in vitro expansion. This study aimed to investigate the effect of suramin on chondrocyte differentiation and its underlying mechanism.

Aims

Therapeutic agents that prevent chondrocyte loss, extracellular matrix (ECM) degradation, and osteoarthritis (OA) progression are required. The expression level of epidermal growth factor (EGF)-like repeats and discoidin I-like domains-containing protein 3 (EDIL3) in damaged human cartilage is significantly higher than in undamaged cartilage. However, the effect of EDIL3 on cartilage is still unknown.

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.

The relationship between heterotopic bone formation and the morphological type of osteoarthritis was examined after 43 hip replacements. Of the 43 hips studied, nine were atrophic, 19 were normotrophic, and 15 were hypertrophic. The incidence of heterotopic bone formation in the atrophic type was 11%, in the normotrophic type 32%, and in the hypertrophic type 87%. The difference between each type was statistically significant (p less than 0.001)

The growth plates of the femoral head of Japanese white rabbits aged 5, 10, 15 and 20 weeks were stained for apoptotic and proliferating chondrocytes using the TUNEL and PCNA antibody staining techniques. Both TUNEL- and PCNA-positive chondrocytes were detected in all of the specimens. The positive ratios of both stainings were calculated for the whole plate and for the resting, proliferating and hypertrophic zones. The highest ratios in both stainings occurred in the hypertrophic zone in all age groups. With growth, the TUNEL-positive ratio increased whereas the proliferating ratio decreased. We suggest that the increase in chondrocytic death by apoptosis and the decrease in cell proliferation potential led to closure of the growth plate

We present a series of ten hypertrophic nonunions in which bony alignment and length were restored and union induced by external fixation and callus distraction. The mean length gained was 3.5 cm (1 to 6) and the mean angular correction was 13.5° (0 to 40). The mean treatment time was 10.2 months (3 to 15) and mean follow-up was 40 months (6 to 71). There have been no refractures or loss of correction or length. The technique of callus distraction at a site of hypertrophic nonunion can correct shortening and angulation as well as induce bony union. No extra equipment is needed beyond readily-available external fixation systems

Experimentally produced fractures in long bones studied by light and electron microscopic histochemistry were found to heal by a process of enchondral calcification. There was intense proliferation in the cells of the cambium layer of the periosteum, with differentiation to chondroblasts and osteoblasts, suggesting that this layer was the primary tissue responsible for development of the callus. Cytoplasmic processes of the hypertrophic chondrocytes appeared to bud and produce matrix vesicles. Alkaline phosphatase activity was detected along the plasma membrane of the hypertrophic chondrocytes and around the matrix vesicles, before any signs of mineral deposition. Calcification took place by deposition of hydroxyapatite crystals in and around these matrix vesicles which frequently showed alkaline phosphatase activity. It is suggested that there is a close functional association between alkaline phosphatase activity and calcification in the process of fracture healing, which is another type of enchondral calcification mediated by matrix vesicles

Aims

This study reports mid-term outcomes after periacetabular osteotomy (PAO) exclusively in a borderline hip dysplasia (BHD) population to provide a contrast to published outcomes for arthroscopic surgery of the hip in BHD.

We compared growth in vascularised allograft transplants, autografts and in non-operated physes in rabbits immunosuppressed with cyclosporin A and in non-immunosuppressed animals. Molecular haplotyping was undertaken before operation to ensure allogenicity. Postoperative bone scans and fluorochrome labelling were used to confirm physeal vascularity. The animals were killed at three or five weeks. Proximal tibial physeal autografts, with or without cyclosporin A, or allografts with cyclosporin A, grew at similar rates to the physes of non-operated rabbits. All the operated physes grew at rates significantly greater than their contralateral controls. 99mTc-MDP bone scans accurately predicted the viability of the epiphyseal plate. Quantitative histomorphological analysis of the heights of the physeal proliferative and hypertrophic zones showed that successful physeal transplants have a normal appearance, but when unsuccessful have thickened hypertrophic zones compatible with physeal ischaemia. We discuss the significance of these results in relation to the transplantation of physes in children

Aims

Eccentric reductions may become concentric through femoral head ‘docking’ (FHD) following closed reduction (CR) for developmental dysplasia of the hip (DDH). However, changes regarding position and morphology through FHD are not well understood. We aimed to assess these changes using serial MRI.

Chondrocytes of the growth plate are generally assumed to undergo apoptosis, but the mechanisms which induce this cell death are not known. The Fas receptor is a mediator of the apoptotic signal in some systems. We studied its expression in situ in growth plates of rabbits aged from five to 20 weeks. In addition, we investigated the immunolocalisation in the growth plates of the bone proteins, osteonectin and osteocalcin, and the changes in their expression with age. The Fas-positive chondrocytes were found mostly in the hypertrophic zone, as were the osteonectin-positive and osteocalcin-positive cells. The percentage of Fas-positive cells increased with age whereas little change was found in the number of osteonectin-positive and osteocalcin-positive chondrocytes. Many of the Fas-positive chondrocytes were also TUNEL-positive. This strongly suggests that apoptosis in the growth plate is mediated through the Fas system. Double immunostaining for osteocalcin and Fas showed that not all hypertrophic chondrocytes were of the same cell type. Some chondrocytes stained for osteocalcin only, others for Fas only, while some were positive for both

Aims

To explore the novel molecular mechanisms of histone deacetylase 4 (HDAC4) in chondrocytes via RNA sequencing (RNA-seq) analysis.

Aims

Pigment epithelium-derived factor (PEDF) is known to induce several types of tissue regeneration by activating tissue-specific stem cells. Here, we investigated the therapeutic potential of PEDF 29-mer peptide in the damaged articular cartilage (AC) in rat osteoarthritis (OA).

We studied the cellular response to physeal distraction in the growth plates of skeletally immature rabbits. We used a new method of labelling and detection of proliferating cells with bromodeoxyuridine (BUdR) and an anti-BUdR antibody. The application of an external fixator but no distraction force produced no changes in the growth plates. After five days of distraction at a maximum force of 20 N, the growth plate became thicker, mainly because of an increase in the number of hypertrophic chondrocytes, but there was no evidence of increased cell proliferation. Recent fractures were seen at the junction of growth plate and metaphysis but the increase in bone length was insignificant. After ten days of distraction at the same maximum force, the chondrocyte columns had become disorganised and cell proliferation was significantly decreased. There was an increase in bone length due to distraction of the fracture gap. In this model, physeal distraction did not stimulate cell proliferation, but actually inhibited it. The apparent increase in growth-plate thickness produced by distraction is not due to increased cell production, but results from inhibition of endochondral ossification and the consequent accumulation of hypertrophic chondrocytes. Any growth after distraction depends on the ability of growth-plate chondrocytes to divide. The decrease in proliferative activity which we found after ten days of distraction suggests the need for caution in the use of such procedures in young children

Aims

It is not known whether preservation of the capsule of the hip positively affects patient-reported outcome measures (PROMs) in total hip arthroplasty using the direct anterior approach (DAA-THA). A recent randomized controlled trial found no clinically significant difference at one year postoperatively. This study aimed to determine whether preservation of the anterolateral capsule and anatomical closure improve the outcome and revision rate, when compared with resection of the anterolateral capsule, at two years postoperatively.

1. It has been shown that in experimental rickets the well known changes in the epiphysial cartilage which so seriously affect growth are accompanied by severe interference with the progress of the metaphysial vessels into the growth cartilage. 2. Further evidence has been found that, by the repeated increase in their number, the cartilage cells occupying the more distal part of the proliferative segment become more and more affected by their remoteness from the epiphysial vessels, which supply the transudates to these cells. At a given distance these cells are affected and change, becoming hypertrophic, with increasingly large vacuolae, and are rich in glycogen and alkaline phosphatase. 3. The hypertrophic cells alter the nature of the intercellular substance they deposit and this becomes calcifiable. Provided that the metaphysial vessels are situated at an appropriate distance–about three cell capsules away–and that the blood has its necessary components, calcification occurs. 4. Calcification produces the advancing, rigid multitubular structure within which the progressing metaphysial vessels are protected. 5. The interruption of calcification by the withdrawal of fat-soluble vitamins breaks down the whole mechanism of growth and stops the vessels growing into their proper position. The administration of the required vitamins re-establishes the normal sequence of events and allows the vessels to play their decisive role in osteogenesis. 6. Any mechanism which causes the interruption of the vascular progression, whether from metaphysial ischaemia (Trueta and Amato 1960), from severe pressure (Trueta and Trias 1961) or from lack of calcification by withdrawing the fat-soluble vitamins, equally interrupts growth

Aims

Osteoarthritis (OA) is the most prevalent systemic musculoskeletal disorder, characterized by articular cartilage degeneration and subchondral bone (SCB) sclerosis. Here, we sought to examine the contribution of accelerated growth to OA development using a murine model of excessive longitudinal growth. Suppressor of cytokine signalling 2 (SOCS2) is a negative regulator of growth hormone (GH) signalling, thus mice deficient in SOCS2 (Socs2^-/-) display accelerated bone growth.

Bone morphogenetic protein (BMP) has a crucial role in osteochondrogenesis of bone formation as well as in the repair of fractures. The interaction between hedgehog protein and BMPs is inferred from recent molecular studies. Hedgehog genes encode secreted proteins which mediate patterning and growth during skeletal development. We have shown that Indian hedgehog gene (Ihh) is expressed in cartilage anlage and later in mature and hypertrophic chondrocytes. This finding suggests that Ihh may regulate the development of chondrocytes. Our results in this study have shown that Ihh transcripts were expressed in hypertrophic chondrocytes in mice at three days but not at three weeks, although a similar expression pattern of α1 (X) collagen could be observed in both types of cartilage. To investigate the possibility that there are direct and age-dependent functions of Ihh in chondrocytes, cultured chondrocytes were treated with the amino-terminal fragment of Sonic hedgehog protein (Shh-N) which can functionally substitute for Ihh protein. Shh-N did not affect the proliferation and differentiation of chondrocytes from three-week-old mice but had a significant effect on three-day-old mice. It enhanced proliferation up to 128% of the control culture in a dose-dependent manner. Although there was no effect in Shh-N-treated cultures, Shh-N enhanced the stimulatory effect of parathyroid hormone (PTH) on the synthesis of proteoglycans. Because the effects of Shh-N on chondrocyte differentiation in this culture system differed from those of bone morphogenetic protein-2 (BMP2) and PTH, in terms of proteoglycan synthesis and ALPase activity, it is unlikely that BMP2 or PTH/PTH-related protein mediates the direct effects of Ihh in chondrocytes. Our study shows that Ihh can function in chondrocytes in a direct and age-dependent fashion

Displaced fractures of the distal radius in children are usually reduced under sedation or general anaesthesia to restore anatomical alignment before the limb is immobilized. However, there is growing evidence of the ability of the distal radius to remodel rapidly, raising doubts over the benefit to these children of restoring alignment. There is now clinical equipoise concerning whether or not young children with displaced distal radial fractures benefit from reduction, as they have the greatest ability to remodel. The Children’s Radius Acute Fracture Fixation Trial (CRAFFT), funded by the National Institute for Health and Care Research, aims to definitively answer this question and determine how best to manage severely displaced distal radial fractures in children aged up to ten years.

Cite this article: Bone Joint J 2024;106-B(1):16–18.

Aims

The aim of this study was to assess the safety and clinical outcome of patients with a femoral shaft fracture and a previous complex post-traumatic femoral malunion who were treated with a clamshell osteotomy and fixation with an intramedullary nail (IMN).

Aims

Implantation of ultra-purified alginate (UPAL) gel is safe and effective in animal osteochondral defect models. This study aimed to examine the applicability of UPAL gel implantation to acellular therapy in humans with cartilage injury.

The June 2024 Foot & Ankle Roundup³⁶⁰ looks at: First MTPJ fusion in young versus old patients; Minimally invasive calcaneum Zadek osteotomy and the effect of sequential burr passes; Comparison between Achilles tendon reinsertion and dorsal closing wedge calcaneal osteotomy for the treatment of insertional Achilles tendinopathy; Revision ankle arthroplasty – is it worthwhile?; Tibiotalocalcaneal arthrodesis or below-knee amputation – salvage or sacrifice?; Fusion or replacement for hallux rigidus?.

Aims

The aim of this study was to reassess the rate of neurological, psoas-related, and abdominal complications associated with L4-L5 lateral lumbar interbody fusion (LLIF) undertaken using a standardized preoperative assessment and surgical technique.

Aims

To explore the synovial expression of mucin 1 (MUC1) and its role in rheumatoid arthritis (RA), as well as the possible downstream mechanisms.

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This systematic review aimed to summarize the full range of complications reported following ankle arthroscopy and the frequency at which they occur.

Aims

We aimed to develop a gene signature that predicts the occurrence of postmenopausal osteoporosis (PMOP) by studying its genetic mechanism.

Transforming growth factor-beta2 (TGF-β2) is recognized as a versatile cytokine that plays a vital role in regulation of joint development, homeostasis, and diseases, but its role as a biological mechanism is understood far less than that of its counterpart, TGF-β1. Cartilage as a load-resisting structure in vertebrates however displays a fragile performance when any tissue disturbance occurs, due to its lack of blood vessels, nerves, and lymphatics. Recent reports have indicated that TGF-β2 is involved in the physiological processes of chondrocytes such as proliferation, differentiation, migration, and apoptosis, and the pathological progress of cartilage such as osteoarthritis (OA) and rheumatoid arthritis (RA). TGF-β2 also shows its potent capacity in the repair of cartilage defects by recruiting autologous mesenchymal stem cells and promoting secretion of other growth factor clusters. In addition, some pioneering studies have already considered it as a potential target in the treatment of OA and RA. This article aims to summarize the current progress of TGF-β2 in cartilage development and diseases, which might provide new cues for remodelling of cartilage defect and intervention of cartilage diseases.

Aims

Abnormal lipid metabolism is involved in the development of osteoarthritis (OA). Growth differentiation factor 11 (GDF11) is crucial in inhibiting the differentiation of bone marrow mesenchymal stem cells into adipocytes. However, whether GDF11 participates in the abnormal adipogenesis of chondrocytes in OA cartilage is still unclear.

Osteoarthritis (OA) is a highly prevalent degenerative joint disorder characterized by joint pain and physical disability. Aberrant subchondral bone induces pathological changes and is a major source of pain in OA. In the subchondral bone, which is highly innervated, nerves have dual roles in pain sensation and bone homeostasis regulation. The interaction between peripheral nerves and target cells in the subchondral bone, and the interplay between the sensory and sympathetic nervous systems, allow peripheral nerves to regulate subchondral bone homeostasis. Alterations in peripheral innervation and local transmitters are closely related to changes in nociception and subchondral bone homeostasis, and affect the progression of OA. Recent literature has substantially expanded our understanding of the physiological and pathological distribution and function of specific subtypes of neurones in bone. This review summarizes the types and distribution of nerves detected in the tibial subchondral bone, their cellular and molecular interactions with bone cells that regulate subchondral bone homeostasis, and their role in OA pain. A comprehensive understanding and further investigation of the functions of peripheral innervation in the subchondral bone will help to develop novel therapeutic approaches to effectively prevent OA, and alleviate OA pain.

Cite this article: Bone Joint Res 2022;11(7):439–452.

Aims

Vertebrates have adapted to life on Earth and its constant gravitational field, which exerts load on the body and influences the structure and function of tissues. While the effects of microgravity on muscle and bone homeostasis are well described, with sarcopenia and osteoporosis observed in astronauts returning from space, the effects of shorter exposures to increased gravitational fields are less well characterized. We aimed to test how hypergravity affects early cartilage and skeletal development in a zebrafish model.

Aims

Slipped upper femoral epiphysis (SUFE) has well documented biochemical and mechanical risk factors. Femoral and acetabular morphologies seem to be equally important. Acetabular retroversion has a low prevalence in asymptomatic adults. Hips with dysplasia, osteoarthritis, and Perthes’ disease, however, have higher rates, ranging from 18% to 48%. The aim of our study was to assess the prevalence of acetabular retroversion in patients presenting with SUFE using both validated radiological signs and tomographical measurements.

Outcomes following different types of surgical intervention for femoroacetabular impingement (FAI) are well reported individually but comparative data are deficient. The purpose of this study was to conduct a systematic review (SR) and meta-analysis to analyze the outcomes following surgical management of FAI by hip arthroscopy (HA), anterior mini open approach (AMO), and surgical hip dislocation (SHD). This SR was registered with PROSPERO. An electronic database search of PubMed, Medline, and EMBASE for English and German language articles over the last 20 years was carried out according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We specifically analyzed and compared changes in patient-reported outcome measures (PROMs), α-angle, rate of complications, rate of revision, and conversion to total hip arthroplasty (THA). A total of 48 articles were included for final analysis with a total of 4,384 hips in 4,094 patients. All subgroups showed a significant correction in mean α angle postoperatively with a mean change of 28.8° (95% confidence interval (CI) 21 to 36.5; p < 0.01) after AMO, 21.1° (95% CI 15.1 to 27; p < 0.01) after SHD, and 20.5° (95% CI 16.1 to 24.8; p < 0.01) after HA. The AMO group showed a significantly higher increase in PROMs (3.7; 95% CI 3.2 to 4.2; p < 0.01) versus arthroscopy (2.5; 95% CI 2.3 to 2.8; p < 0.01) and SHD (2.4; 95% CI 1.5 to 3.3; p < 0.01). However, the rate of complications following AMO was significantly higher than HA and SHD. All three surgical approaches offered significant improvements in PROMs and radiological correction of cam deformities. All three groups showed similar rates of revision procedures but SHD had the highest rate of conversion to a THA. Revision rates were similar for all three revision procedures.

Aims

Tert-butylhydroquinone (tBHQ) has been identified as an inhibitor of oxidative stress-induced injury and apoptosis in human neural stem cells. However, the role of tBHQ in osteoarthritis (OA) is unclear. This study was carried out to investigate the role of tBHQ in OA.

We attempted to characterise the biological quality and regenerative potential of chondrocytes in osteochondritis dissecans (OCD). Dissected fragments from ten patients with OCD of the knee (mean age 27.8 years (16 to 49)) were harvested at arthroscopy. A sample of cartilage from the intercondylar notch was taken from the same joint and from the notch of ten patients with a traumatic cartilage defect (mean age 31.6 years (19 to 52)). Chondrocytes were extracted and subsequently cultured. Collagen types 1, 2, and 10 mRNA were quantified by polymerase chain reaction. Compared with the notch chondrocytes, cells from the dissecate expressed similar levels of collagen types 1 and 2 mRNA. The level of collagen type 10 message was 50 times lower after cell culture, indicating a loss of hypertrophic cells or genes. The high viability, retained capacity to differentiate and metabolic activity of the extracted cells suggests preservation of the intrinsic repair capability of these dissecates. Molecular analysis indicated a phenotypic modulation of the expanded dissecate chondrocytes towards a normal phenotype. Our findings suggest that cartilage taken from the dissecate can be reasonably used as a cell source for chondrocyte implantation procedures.

We present three cases of intramuscular haemangioma adjacent to bone in the lower limb. All patients had local pain during the third decade. Plain radiographs showed an irregular or hypertrophic periosteal reaction on the shaft of the fibula and an intramuscular mass adjacent to the bone with inhomogenous high signal intensity on MRI. These lesions mimic periosteal or parosteal tumours

The usual causes of pain after total knee replacement are well known, but there are a small number of patients in whom its aetiology is obscure. We report three patients with a specific pain syndrome caused by hypertrophic fibrous tissue in the intercondylar notch. Excision of this tissue relieved the symptoms completely

Clavicular fractures are occasionally responsible for lesions of the brachial plexus. The symptoms are usually delayed and due to compression by hypertrophic callus, nonunion or a subclavian pseudoaneurysm. We describe a patient in whom a displaced bone fragment was pressing on the retroclavicular part of the brachial plexus, leading to early symptoms of a lesion of the posterior cord. Internal fixation of the clavicle and external neurolysis of the brachial plexus gave an almost full recovery

We have performed simple bone grafting in four elderly patients with pain due to unstable pseudarthroses in the osteoporotic spine after compression fracture. At operation, we observed abnormal movement of the affected vertebral body which was covered with a hypertrophic membrane; this seemed to inhibit the blood supply to the lesion. The thick membrane and avascular granulation in the false joint were excised and bone grafting carried out. Symptoms were dramatically improved immediately after operation and bony union was confirmed in the three surviving patients

We obtained specimens of growth-plate cartilage from four patients with osteogenesis imperfecta. Light microscopy showed structural changes in the tissue and morphological changes in chondrocytes and matrix, particularly in the hypertrophic zone. There were changes in the process of calcification in the primary mineralisation zone of the cartilage. We also found histochemical changes in the matrix glycosaminoglycans (GAGs) in the zones where physiological mineralisation was disturbed and where the trabeculae were interrupted and poorly mineralised. In addition to the known molecular defects in collagen, changes in GAGs and non-collagenous proteins are important factors in the pathogenesis of the disease