1. The surface of mature adult human articular cartilage from the knee has been studied by electron microscopy in eleven patients ranging in age from thirty-seven to eighty-three years. The ultrastructural appearance varies from person to person and often from area to area in the same specimen. These variations range from an intact surface to one showing overt fibrillation visible with the light microscope. 2. In areas where the articular surface appears intact the underlying superficial matrix consists of closely packed collagen fibres with only a small amount of interfibrillary ground substance. The collagen fibres show a predominantly tangential orientation in this region of the cartilage. Osmophilic lipidic bodies are sometimes seen in the matrix very close to the joint surface. 3. The appearances under the electron microscope are altered in what is interpreted as an early ultrastructural change in the development of cartilage fibrillation. In the affected areas the collagen fibres show abnormally wide separation by an excessive amount of interfibrillary matrix. Collagen fibres become directly exposed to the joint cavity, and the surface can also show accumulations of finely granular material and sometimes tuft-like projections containing collagen fibres and fine fibrils. At a slightly later stage shallow clefts and steeply sloping curves are apparent at the surface. It is suggested that these various alterations precede the development of overt fibrillation visible under the light microscope. 4. Electron micrographs occasionally show small "blisters" at the articular surface. Electron microscopy has not given evidence of shedding of cells into the joint cavity from non-fibrillated areas of adult human articular cartilage. Cells can, however, sometimes become exposed at the surface in fibrillated areas

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Osteoarthritis (OA) is the most prevalent joint disease. However, the specific and definitive genetic mechanisms of OA are still unclear.

Conventional treatment of mild slipped capital femoral epiphysis consists of fixation in situ with wires or screws. Recent contributions to the literature suggest that even a mild slip may lead to early damage of the acetabular labrum and adjacent cartilage by abutment of a prominent femoral metaphysis. It has been suggested that the appropriate treatment in mild slipped capital femoral epiphysis should not only prevent further slipping of the epiphysis, but also address potential femoroacetabular impingement by restoring the anatomy of the proximal femur. Between October 1984 and December 1995 we treated 16 patients for unilateral mild slipped capital femoral epiphysis by fixation in situ with Kirschner wires. In this study we have reviewed these patients for clinical and radiological evidence of femoroacetabular impingement. There was little clinical indication of impingement but radiological evaluation assessing the femoral head-neck ratio and measuring the Nötzli α angle on the anteroposterior and cross-table radiographs showed significant alterations in the proximal femur. None of the affected hips had a normal head-neck ratio and the mean α angle was 86° (55° to 99°) and 55° (40° to 94°) on the anteroposterior and lateral cross-table radiographs, respectively. While our clinical data favours conventional treatment, our radiological findings are in support of restoring the anatomy of the proximal femur to avoid or delay the development of femoroacetabular impingement following mild slipped capital femoral epiphysis

A balanced inflammatory response is important for successful fracture healing. The response of osteoporotic fracture healing is deranged and an altered inflammatory response can be one underlying cause. The objectives of this review were to compare the inflammatory responses between normal and osteoporotic fractures and to examine the potential effects on different healing outcomes. A systematic literature search was conducted with relevant keywords in PubMed, Embase, and Web of Science independently. Original preclinical studies and clinical studies involving the investigation of inflammatory response in fracture healing in ovariectomized (OVX) animals or osteoporotic/elderly patients with available full text and written in English were included. In total, 14 articles were selected. Various inflammatory factors were reported; of those tumour necrosis factor-α (TNF-α) and interleukin (IL)-6 are two commonly studied markers. Preclinical studies showed that OVX animals generally demonstrated higher systemic inflammatory response and poorer healing outcomes compared to normal controls (SHAM). However, it is inconclusive if the local inflammatory response is higher or lower in OVX animals. As for clinical studies, they mainly examine the temporal changes of the inflammatory stage or perform comparison between osteoporotic/fragility fracture patients and normal subjects without fracture. Our review of these studies emphasizes the lack of understanding that inflammation plays in the altered fracture healing response of osteoporotic/elderly patients. Taken together, it is clear that additional studies, preclinical and clinical, are required to dissect the regulatory role of inflammatory response in osteoporotic fracture healing.

Cite this article: Bone Joint Res 2020;9(7):368–385.

We investigated the association between the radiological findings and the symptoms arising from the patellofemoral joint in advanced osteoarthritis (OA) of the knee. Four radiological features, joint space narrowing, osteophyte formation, translation of the patella and focal attrition were assessed in 151 consecutive osteoarthritic knees in 107 patients undergoing total knee replacement. The symptoms which were assessed included anterior knee pain which was scored, the ability to rise from a chair and climb stairs, and quadriceps weakness. Among the radiological features, only patellar translation and obliteration of the joint space had a statistically significant association with anterior knee pain (odds ratio (OR) 4.85; 95% confidence interval (CI) 1.83 to 12.88 and OR 11.23; 95% CI 2.44 to 51.62) respectively. Patellar translation had a statistically significant association with difficulty in rising from a chair (OR 9.06; 95% CI 1.75 to 45.11). Other radiological features, including osteophytes, joint space narrowing, and focal attrition had no significant association. Our study indicates that the radiological findings of patellar translation and significant loss of cartilage are predictive of patellofemoral symptoms and functional limitation in advanced OA of the knee

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The prevalence of combined abnormalities of femoral torsion (FT) and tibial torsion (TT) is unknown in patients with femoroacetabular impingement (FAI) and hip dysplasia. This study aimed to determine the prevalence of combined abnormalities of FT and TT, and which subgroups are associated with combined abnormalities of FT and TT.

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To evaluate the outcomes of terrible triad injuries (TTIs) in mid-term follow-up and determine whether surgical treatment of the radial head influences clinical and radiological outcomes.

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The aim of this study was to analyze the association between the shape of the distal radius sigmoid notch and triangular fibrocartilage complex (TFCC) foveal tear.

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Femoroacetabular impingement (FAI) is a potential cause of hip osteoarthritis (OA). The purpose of this study was to investigate the expression profile of matrix metalloproteinases (MMPs) in the labral tissue with FAI pathology.

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Cigarette smoking has a negative impact on the skeletal system, causes a decrease in bone mass in both young and old patients, and is considered a risk factor for the development of osteoporosis. In addition, it disturbs the bone healing process and prolongs the healing time after fractures. The mechanisms by which cigarette smoking impairs fracture healing are not fully understood. There are few studies reporting the effects of cigarette smoking on new blood vessel formation during the early stage of fracture healing. We tested the hypothesis that cigarette smoke inhalation may suppress angiogenesis and delay fracture healing.

Chondrocyte hypertrophy represents a crucial turning point during endochondral bone development. This process is tightly regulated by various factors, constituting a regulatory network that maintains normal bone development. Histone deacetylase 4 (HDAC4) is the most well-characterized member of the HDAC class IIa family and participates in different signalling networks during development in various tissues by promoting chromatin condensation and transcriptional repression. Studies have reported that HDAC4-null mice display premature ossification of developing bones due to ectopic and early-onset chondrocyte hypertrophy. Overexpression of HDAC4 in proliferating chondrocytes inhibits hypertrophy and ossification of developing bones, which suggests that HDAC4, as a negative regulator, is involved in the network regulating chondrocyte hypertrophy. Overall, HDAC4 plays a key role during bone development and disease. Thus, understanding the role of HDAC4 during chondrocyte hypertrophy and endochondral bone formation and its features regarding the structure, function, and regulation of this process will not only provide new insight into the mechanisms by which HDAC4 is involved in chondrocyte hypertrophy and endochondral bone development, but will also create a platform for developing a therapeutic strategy for related diseases.

Cite this article: Bone Joint Res. 2020;9(2):82–89.

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Inadvertent soft tissue damage caused by the oscillating saw during total knee arthroplasty (TKA) occurs when the sawblade passes beyond the bony boundaries into the soft tissue. The primary objective of this study is to assess the risk of inadvertent soft tissue damage during jig-based TKA by evaluating the excursion of the oscillating saw past the bony boundaries. The second objective is the investigation of the relation between this excursion and the surgeon’s experience level.

1. The fibrillar networks of adult human articular cartilage, taken from femoral and acetabular specimens, have been systematically examined by scanning electron microscopy. The internal structures revealed by rupturing the tissue were compared with published findings from transmission electron microscope studies. 2. Though this technique demonstrated the internal fibrillar appearance of cartilage to a remarkable degree, it had several attendant limitations. On final drying, specimens generally exhibited shrinkage which varied within wide limits; this could have altered the internal architecture to some extent. In addition, the rupturing technique, which at the time of this investigation was the only satisfactory method of revealing the fibrillar cartilage structure, may well have had a great influence on the fibril orientations. 3. The fibrils revealed no characteristic collagen periodicity and were considerably thicker than those observed by transmission electron microscopy. It is suggested that a coating of mucin on the collagen fibrils might account for this. 4. At low magnifications the torn layers in the fractured surfaces extended radially from the calcified zone and turned obliquely at or near the articular surface to merge with the distinctly layered superficial zone, thus forming arcade-like structures. That these were not artefacts produced by the fracturing technique was shown by their similarity to the classical arcade pattern of light microscopy. However, the factor which governed the direction of these planes of weakness, be it collagen, mucopolysaccharides or cells, could not be satisfactorily determined. 5. At higher magnifications only three regions of distinct fibrillar organisation could be identified: 1) a surface layer consisting of a random fibrillar network; 2) a superficial zone composed of layers of fibrillar network, intersecting and overlapping in planes parallel to the surface; and 3) elsewhere below the superficial zone a network of virtually random fibrils which extended to the calcified region with apparently little variation in thickness or density. There was little variation from this pattern even in aged fibrillated specimens. 6. At the lower magnification range the scanning electron microscope has revealed the arcade pattern described by light microscopy, while at the higher magnifications the fibrillar organisation as seen by scanning electron microscopy correlated well with the concepts developed by transmission electron microscopy, that is, a random network of fibrils overlaid at the articular surface by a membrane-like system of bundled fibrils. 7. A possible role in the transmission of joint forces is outlined for the above fibrillar organisation

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In the context of tendon degenerative disorders, the need for innovative conservative treatments that can improve the intrinsic healing potential of tendon tissue is progressively increasing. In this study, the role of pulsed electromagnetic fields (PEMFs) in improving the tendon healing process was evaluated in a rat model of collagenase-induced Achilles tendinopathy.

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Metabolic profiling is a top-down method of analysis looking at metabolites, which are the intermediate or end products of various cellular pathways. Our primary objective was to perform a systematic review of the published literature to identify metabolites in human synovial fluid (HSF), which have been categorized by metabolic profiling techniques. A secondary objective was to identify any metabolites that may represent potential biomarkers of orthopaedic disease processes.

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It remains controversial whether patellofemoral joint pathology is a contraindication to lateral unicompartmental knee arthroplasty (UKA). This study aimed to evaluate the effect of preoperative radiological degenerative changes and alignment on patient-reported outcome scores (PROMs) after lateral UKA. Secondarily, the influence of lateral UKA on the alignment of the patellofemoral joint was studied.