A retrospective analysis was performed of eight patients with an open triradiate cartilage, who underwent resection for osteosarcoma and reconstruction of the proximal femur with a hemiarthroplasty, in order to identify changes of acetabular development. An analysis of the centre-edge angle, teardrop-to-medial prosthesis distance, superior joint space, teardrop-to-superior prosthesis distance, degree of lateral translation, and arthritic changes, was performed on serial radiographs. The median age at the time of the initial surgery was 11 years (5 to 14). All patients developed progressive superior and lateral migration of the prosthetic femoral head. Following hemiarthroplasty in the immature acetabulum, the normal deepening and enlargement of the acetabulum is arrested. The degree of superior and lateral migration of the prosthetic head depends on the age at diagnosis and the length of follow-up

Trochlear dysplasia is an important anatomical abnormality in symptomatic patellar instability. Our study assessed the mismatch between the bony and cartilaginous morphology in patients with a dysplastic trochlea compared with a control group. MRI scans of 25 knees in 23 patients with trochlear dysplasia and in 11 patients in a randomly selected control group were reviewed retrospectively in order to assess the morphology of the cartilaginous and bony trochlea. Inter- and intra-observer error was assessed. In the dysplastic group there were 15 women and eight men with a mean age of 20.4 years (14 to 30). The mean bony sulcus angle was 167.9° (141° to 203°), whereas the mean cartilaginous sulcus angle was 186.5° (152° to 214°; p < 0.001). In 74 of 75 axial images (98.7%) the cartilaginous contour was different from the osseous contour on subjective assessment, the cartilage exacerbated the abnormality. Our study shows that the morphology of the cartilaginous trochlea differs markedly from that of the underlying bony trochlea in patients with trochlear dysplasia. MRI is necessary in order to demonstrate the pathology and to facilitate surgical planning

We have compared the results at a mean follow-up of 13 years (11 to 14) of two groups of supination-external rotation type-4 fractures of the ankle, in one of which there was a fracture of the medial malleolus and in the other the medial deltoid ligament had been partially or completely ruptured. Of 66 patients treated operatively between 1993 and 1997, 36 were available for follow-up. Arthroscopy had been performed in all patients pre-operatively to assess the extent of the intra-articular lesions. The American Orthopaedic Foot and Ankle Society hind-foot score was used for clinical evaluation and showed a significant difference in both the total and the functional scores (p < 0.05), but not in those for pain or alignment, in favour of the group with a damaged deltoid ligament (p < 0.05). The only significant difference between the groups on the short-form 36 quality-of-life score was for bodily pain, again in favour of the group with a damaged deltoid ligament. There was no significant difference between the groups in the subjective visual analogue scores or in the modified Kannus radiological score. Arthroscopically, there was a significant difference with an increased risk of loose bodies in the group with an intact deltoid ligament (p < 0.005), although there was no significant increased risk of deep cartilage lesions in the two groups. At a mean follow-up of 13 years after operative treatment of a supination-external rotation type-4 ankle fracture patients with partial or complete rupture of the medial deltoid ligament tended to have a better result than those with a medial malleolar fracture

Plasmin, a proteolytic enzyme derived from the blood, may be activated in synovial fluid both by trauma to synovial tissue and cartilage, and by kinases produced by streptococci and staphylococci. Plasmin normally removes fibrin, but, when in excess, attacks the protein of cartilage matrix. Conversely, excess inhibitor favours the persistence of fibrin and subsequent fibrosis. The relationship of excess protease to the chondrolysis of suppurative arthritis and of excess inhibitor to pannus formation and fibrous ankylosis in tuberculous and rheumatoid arthritis are discussed

A diastasis between the femoral head and the acetabulum can be achieved for a short while by the application of manual traction on the lower extremity. The intra-articular low-pressure area can be visualised radiographically and is known as a "vacuum phenomenon". The resulting arthrogram clearly outlines the shape, thickness and extent of the cartilage. In the presence of an effusion the diastasis occurs without a vacuum phenomenon. This simple, non-invasive and inoffensive method of traction radiography will not only show abnormalities of the cartilage but also demonstrate the presence or absence of an effusion of the hip

A method for direct measurement of the local pressures in the acetabular cartilage is described. Pressure transducers were introduced into the subchondral bone and positioned there in contrast with the cartilage: the transducers were calibrated in situ. Twelve cadaveric hips were prepared in this way and the pressures were measured with the joint loaded in flexion, extension, abduction, adduction, and in lateral and medial rotation. The highest pressures were recorded in the anterior and posterior segments of the acetabulum; the lowest pressures were constantly found at the zenith of the joint. The relationship of these findings to the pathogenesis of osteoarthritis is considered

The articular cartilage of the patella was studied in 100 knees at necropsy. In twenty-one of these knees the cartilage changes were related to the trabecular architecture of the underlying bone. It would appear that the initiation and location of cartilage damage and its rate and degree of progression are related to the relative stiffness of the underlying cancellous bone. On the basis of our observations we suggest that the diagnosis "chondromalacia of the patella" should be reserved for patients with asymptomatic or transiently symptomatic fibrillation of the articular cartilage of the central medial patellar facet. Those patients with persistent patellofemoral pain should be considered to have some other syndrome

1. One hundred and twenty-six metacarpo-phalangeal joints affected by rheumatoid arthritis were studied macroscopically at either synovectomy or arthroplasty. 2. The sites and extent of the initial erosion corresponded with the sites and size of the synovial pouches. 3. The areas of cartilage degeneration were related to the degree of flexion, ulnar deviation and subluxation of the proximal phalanx on the metacarpal head. 4. The routine radiographic findings were not a true reflection of all the pathological changes within the joint. 5. It is suggested that by encouraging joint movement and preventing deformity the degree of cartilage degeneration may be diminished

1. The age changes in the articular cartilage of the elbow joint are presented from a study of twenty-eight necropsy subjects aged eighteen to eighty-eight years. During early adult life those areas of cartilage which do not usually articulate with opposed cartilage always show some degree of chondromalacia. 2. Evidence is presented that the almost inevitable degeneration of the radio-humeral joint in old age is related to the combination of rotation and hinge movements that occur at that joint. This is in marked contrast with the relative immunity of the humero-ulnar articulation which has hinge movement only

1. A study of normal and osteoarthritic hyaline cartilage has been made with the electron microscope and x-ray diffraction. 2. Normal cartilage consists of a three-dimensional network of collagen fibrils with no preferred orientation, surrounded by a matrix containing polysaccharide. 3. In the osteoarthritic joint the collagen fibrils show definite orientation and a decreased proportion of ground substance. X-ray diffraction confirms this and shows the orientation to be at right angles to the surface of the femoral head. 4. Tensional forces across the joint may explain why osteoarthritic changes first appear in the non-weight-bearing area of the joint

The ability to edit DNA at the nucleotide level using clustered regularly interspaced short palindromic repeats (CRISPR) systems is a relatively new investigative tool that is revolutionizing the analysis of many aspects of human health and disease, including orthopaedic disease. CRISPR, adapted for mammalian cell genome editing from a bacterial defence system, has been shown to be a flexible, programmable, scalable, and easy-to-use gene editing tool. Recent improvements increase the functionality of CRISPR through the engineering of specific elements of CRISPR systems, the discovery of new, naturally occurring CRISPR molecules, and modifications that take CRISPR beyond gene editing to the regulation of gene transcription and the manipulation of RNA. Here, the basics of CRISPR genome editing will be reviewed, including a description of how it has transformed some aspects of molecular musculoskeletal research, and will conclude by speculating what the future holds for the use of CRISPR-related treatments and therapies in clinical orthopaedic practice.

Cite this article: Bone Joint Res 2020;9(7):351–359.

Aims

The diagnosis of developmental dysplasia of the hip (DDH) is challenging owing to extensive variation in paediatric pelvic anatomy. Artificial intelligence (AI) may represent an effective diagnostic tool for DDH. Here, we aimed to develop an anteroposterior pelvic radiograph deep learning system for diagnosing DDH in children and analyze the feasibility of its application.

We have investigated in vitro the release kinetics and bioactivity of fibroblast growth factor-2 (FGF-2) released from a carrier of fibrin sealant. In order to evaluate the effects of the FGF-2 delivery mechanism on the repair of articular cartilage, full-thickness cylindrical defects, 5 mm in diameter and 4 mm in depth, which were too large to undergo spontaneous repair, were created in the femoral trochlea of rabbit knees. These defects were then filled with the sealant. Approximately 50% of the FGF-2 was released from the sealant within 24 hours while its original bioactivity was maintained. The implantation of the fibrin sealant incorporating FGF-2 successfully induced healing of the surface with hyaline cartilage and concomitant repair of the subchondral bone at eight weeks after the creation of the defect. Our findings suggest that this delivery method for FGF-2 may be useful for promoting regenerative repair of full-thickness defects of articular cartilage in humans

We describe 119 meniscal allograft transplantations performed concurrently with articular cartilage repair in 115 patients with severe articular cartilage damage. In all, 53 (46.1%) of the patients were over the age of 50 at the time of surgery. The mean follow-up was for 5.8 years (2 months to 12.3 years), with 25 procedures (20.1%) failing at a mean of 4.6 years (2 months to 10.4 years). Of these, 18 progressed to knee replacement at a mean of 5.1 years (1.3 to 10.4). The Kaplan-Meier estimated mean survival time for the whole series was 9.9 years (. sd. 0.4). Cox’s proportional hazards model was used to assess the effect of covariates on survival, with age at the time of surgery (p = 0.026) and number of previous operations (p = 0.006) found to be significant. The survival of the transplant was not affected by gender, the severity of cartilage damage, axial alignment, the degree of narrowing of the joint space or medial versus lateral allograft transplantation. Patients experienced significant improvements at all periods of follow-up in subjective outcome measures of pain, activity and function (all p-values < 0.05), with the exception of the seven-year Tegner index score (p = 0.076)

The morphological changes in bone and articular cartilage destruction have been described in sixteen consecutive cases of rheumatoid arthritis in which biopsy material was obtained during synovectomy of the knee. The following observations were made. 1. Bone and cartilage is replaced by fibrous granulation tissue which proliferates from periosteal and perichondrial fibroblasts. 2. These proliferative changes are distinct from the chronic synovitis of rheumatoid disease, but a chronic synovitis is necessary for them to appear. 3. Synovectomy does not remove the cells replacing bone and cartilage but its performance in some ways leads to their regression

The intermittent administration of cortisone in both the young and the mature rabbit is associated with appositional bone growth on the periosteal surfaces of the cranium, premaxilla and middle of the shaft of the femur; each new layer of bone is separated from the next by a darkly haematoxylin-staining "reversal" line. The internal architecture of the bone also changes in consequence of the repeated waves of resorption and deposition of bone round vascular spaces. Cartilaginous growth at the epiphysis in the young rabbit is also affected. The long columns of metaphysial cartilage are replaced by a layer of new bone which partly seals the epiphysial cartilage from the marrow spaces

Aims

This study aimed to identify the tibial component and femoral component coronal angles (TCCAs and FCCAs), which concomitantly are associated with the best outcomes and survivorship in a cohort of fixed-bearing, cemented, medial unicompartmental knee arthroplasties (UKAs). We also investigated the potential two-way interactions between the TCCA and FCCA.

The use of a composite osteochondral device for simulating partial hemiarthroplasty was examined. The device was composed of a polyvinyl alcohol hydrogel and a titanium fibre mesh, acting as artificial cartilage and as porous artificial bone, respectively. The titanium fibre mesh was designed to act as an interface material, allowing firm attachment to both the polyvinyl alcohol gel (through injection moulding) and the femoral joint surface (through bony ingrowth). We implanted 22 of these devices into canine femoral heads. Histological findings from the acetabular cartilage and synovial membrane, as well as the attachment of the prosthesis to bone, were examined up until one year after operation. No marked pathological changes were found and firm attachment of the device to the underlying bone was confirmed. The main potential application for this device is for partial surface replacement of the femoral head after osteonecrosis. Other applications could include articular resurfacing and the replacement of intervertebral discs