We developed a new porous scaffold made from a synthetic polymer, poly(DL-lactide-co-glycolide) (PLG), and evaluated its use in the repair of cartilage. Osteochondral defects made on the femoral trochlear of rabbits were treated by transplantation of the PLG scaffold, examined histologically and compared with an untreated control group. Fibrous tissue was initially organised in an arcade array with poor cellularity at the articular surface of the scaffold. The tissue regenerated to cartilage at the articular surface. In the subchondral area, new bone formed and the scaffold was absorbed. The histological scores were significantly higher in the defects treated by the scaffold than in the control group (p < 0.05). Our findings suggest that in an animal model the new porous PLG scaffold is effective for repairing full-thickness osteochondral defects without cultured cells and growth factors

The aim of this study was to determine whether subchondral bone influences in situ chondrocyte survival. Bovine explants were cultured in serum-free media over seven days with subchondral bone excised from articular cartilage (group A), subchondral bone left attached to articular cartilage (group B), and subchondral bone excised but co-cultured with articular cartilage (group C). Using confocal laser scanning microscopy, fluorescent probes and biochemical assays, in situ chondrocyte viability and relevant biophysical parameters (cartilage thickness, cell density, culture medium composition) were quantified over time (2.5 hours vs seven days). There was a significant increase in chondrocyte death over seven days, primarily within the superficial zone, for group A, but not for groups B or C (p < 0.05). There was no significant difference in cartilage thickness or cell density between groups A, B and C (p > 0.05). Increases in the protein content of the culture media for groups B and C, but not for group A, suggested that the release of soluble factors from subchondral bone may have influenced chondrocyte survival. In conclusion, subchondral bone significantly influenced chondrocyte survival in articular cartilage during explant culture. The extrapolation of bone-cartilage interactions in vitro to the clinical situation must be made with caution, but the findings from these experiments suggest that future investigation into in vivo mechanisms of articular cartilage survival and degradation must consider the interactions of cartilage with subchondral bone

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The aim of this study was to inform the epidemiology and treatment of slipped capital femoral epiphysis (SCFE).

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Anterior cruciate ligament (ACL) rupture commonly leads to post-traumatic osteoarthritis, regardless of surgical reconstruction. This study uses standing MRI to investigate changes in contact area, contact centroid location, and tibiofemoral alignment between ACL-injured knees and healthy controls, to examine the effect of ACL reconstruction on these parameters.

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There is conflicting evidence on the safety of intra-articular injections of hyaluronic acid (HA) or corticosteroids (CSs) before total knee arthroplasty (TKA). We performed a meta-analysis of the relationship between intra-articular injections and subsequent infection rates after TKA.

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The aim of this study was to compare any differences in the primary outcome (biphasic flexion knee moment during gait) of robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) at one year post-surgery.

Acetabular dysplasia was produced in 24 immature white rabbits. A rotational acetabular osteotomy was then carried out and radiological and histological studies of the articular cartilage were made. In the hips which did not undergo osteotomy, radiographs at 26 weeks showed that residual subluxation remained and arthritic changes such as narrowing of the joint space or dislocation were still seen. However, in the operated group there was a remarkable increase in cover, but arthritic changes were not observed. After 24 weeks, the Mankin grading score in the operated group was significantly lower than that in the non-operated group. The latter hips showed an irregular surface of the cartilage, exfoliation and proliferation of synovial tissue. In those undergoing osteotomy, primary cloning of chondrocytes or hypercellularity was seen and at 24 weeks after operation and metaplasia of the cartilage in the fibrous tissue was observed in the boundary between the medial area of the acetabulum and the acetabular fossa

We studied the mechanical properties of cartilage from the apparently unaffected compartment of knees with unicompartmental osteoarthritis (OA). Plugs of cartilage and subchondral bone, 8 mm in diameter, were obtained from the tibial plateau of seven patients treated by total knee replacement. Control specimens were obtained from eight cadaver knees of similar age. Specimens were loaded by a plane-ended indentor in a hydraulic materials testing machine; we measured thickness, 'softness', rate of creep, and compressive strength of the articular cartilage. We found that the 'unaffected' cartilage from OA knees was significantly thinner and softer than control cartilage, and it was slightly, although not significantly, weaker. We conclude that the apparently unaffected cartilage in knees with unicompartmental OA is mechanically inferior to normal cartilage, even although clinically, radiologically and morphologically it appears to be sound

1. The lines of fracture confirm the suggestions of earlier authors on the lines of strength in cartilage, with the additional feature of a transverse plane of weakness at the apex of the calcified zone. 2. The normal nutrition of cartilage is synovial, and access of a free blood supply is followed by destruction of hyaline articular cartilage. 3. Minor traumatic events in the articular lamella are common, particularly in osteoarthritic joints; the results of these on the cartilage are like the changes of osteoarthritis. 4. The removal of uncalcified cartilage can be described in two stages of a physico-chemical kind; the removal of calcified cartilage is a single cellular process. 5. There is evidence that the carbohydrate moiety of cartilage is present in two separable phases, one fixed to collagen, the other free. 6. The repair mechanisms after fracture are those available to restore the damage of osteoarthritis, and reasons can be shown why in fact they are ineffective

1. Experiments are described in which total infarction of the epiphysis was produced in the metatarsal bones of growing rabbits. 2. After operation both proliferation and normal maturation of the cells of the growth plate were slowed or stopped. Cartilage destruction on the metaphysial side of the growth cartilage continued with consequent thinning of the cartilage. Localised areas of cell death appeared in the growth cartilage as early as the second day after operation. These increased in size and led to revascularisation of the epiphysis by metaphysial vessels which grew through the growth cartilage, reaching the epiphysis seven days after operation. The main, central part of the growth cartilage survived intact and its normal structure was restored after epiphysial revascularisation took place. Vessels growing into the bone from outside also contributed to revascularisation of the epiphysis. After revascularisation occurred, new bone formation led to increased radiographic density of the epiphysis

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The aim of this study was to explore the genetic correlation and causal relationship between blood plasma proteins and rheumatoid arthritis (RA).

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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.

Aims

Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA).

The August 2015 Children’s orthopaedics Roundup. 360 . looks at: Learning the Pavlik; MRI and patellar instability; Cerebral palsy and hip dysplasia; ‘Pick your poison’: elastic nailing under the spotlight; Club feet and surgery; Donor site morbidity in vascularised fibular grafting; Cartilage biochemistry with hip dysplasia; SUFE and hip decompression: a good option?

Aims. Several studies have reported the safety and efficacy of subcapital re-alignment for patients with slipped capital femoral epiphysis (SCFE) using surgical dislocation of the hip and an extended retinacular flap. Instability of the hip and dislocation as a consequence of this surgery has only recently gained attention. We discuss this problem with some illustrative cases. Materials and Methods. We explored the literature on the possible pathophysiological causes and surgical steps associated with the risk of post-operative instability and articular damage. In addition, we describe supplementary steps that could be used to avoid these problems. Results. The causes of instability may be divided into three main groups: the first includes causes directly related to SCFE (acetabular labral damage, severe abrasion of the acetabular cartilage, flattening of the acetabular roof and a bell-shaped deformity of the epiphysis); the second, causes not related to the SCFE (acetabular orientation and poor quality of the soft tissues); the third, causes directly related to the surgery (capsulotomy, division of the ligamentum teres, shortening of the femoral neck, pelvi-trochanteric impingement, previous proximal femoral osteotomy and post-operative positioning of the leg). Conclusion. We present examples drawn from our clinical practice, as well as possible ways of reducing the risks of these complications, and of correcting them if they happen. Cite this article: Bone Joint J 2017;99-B:16–21

1. Techniques are described for homografting intact or partly digested hyaline cartilage or isolated chondrocytes on to cancellous bone in rabbits. 2. Material which had been cooled to and thawed from -79 degrees Centigrade either in the presence or absence of the protective substance dimethyl sulphoxide was grafted in the same way. In control experiments samples were boiled before grafting. 3. Necropsies were performed at intervals varying from two to twenty-six weeks later and the graft sites were removed, fixed and decalcified. Paraffin sections were stained histologically. 4. Freshly isolated chondrocytes or chondrocytes which had been frozen in the presence of dimethyl suiphoxide formed new matrix within two weeks and did not succumb to a homograft reaction. By the sixth week they had become aligned in columns surrounded by well stained matrix. There were signs oferosion by invading capillaries and osteoblasts, but no lymphocytes were seen. By the twelfth week invasion by trabeculae of newly formed bone was well advanced and by the twenty-sixth week the grafts were difficult to find although there had been no sign at any stage of an immunological reaction. 5. New matrix was also formed in homografts of hyaline cartilage which had been treated with papain or with papain and collagenase. After freezing in the presence of dimethyl sulphoxide, small areas ofthe grafts seemed to contain living cells which had formed new matrix. Other areas were disintegrating. 6. The homografts of intact cartilage showed a variety of appearances suggesting that the old matrix was gradually leached out and that chondrocytes liberated in vivo formed a new matrix. 7. Intact or partly digested cartilage which had either been frozen without dimethyl suiphoxide or boiled disintegrated and was rapidly replaced by bone after grafting. 8. When specimens of partly digested cartilage or isolated chondrocytes were homografted On to sites denuded of cartilage on the articular surface of the rabbit humeral head, nodules of fresh cartilage were formed. They were embedded in fibrous tissue derived, presumably, from marrow cavities opened up at the time of operation