Aims. To explore the clinical relevance of joint space width (JSW) narrowing on standardized-flexion (SF) radiographs in the assessment of cartilage degeneration in specific subregions seen on MRI sequences in knee osteoarthritis (OA) with neutral, valgus, and varus alignments, and potential planning of partial knee arthroplasty. Methods. We retrospectively reviewed 639 subjects, aged 45 to 79 years, in the Osteoarthritis Initiative (OAI) study, who had symptomatic knees with Kellgren and Lawrence grade 2 to 4. Knees were categorized as neutral, valgus, and varus knees by measuring hip-knee-angles on hip-knee-ankle radiographs. Femorotibial JSW was measured on posteroanterior SF radiographs using a special software. The femorotibial compartment was divided into 16 subregions, and MR-tomographic measurements of cartilage volume, thickness, and subchondral bone area were documented. Linear regression with adjustment for age, sex, body mass index, and Kellgren and Lawrence grade was used. Results. We studied 345 neutral, 87 valgus, and 207 varus knees. Radiological JSW narrowing was significantly (p < 0.01) associated with cartilage volume and thickness in medial femorotibial compartment in neutral (r = 0.78, odds ratio (OR) 2.33) and varus knees (r = 0.86, OR 1.92), and in lateral tibial subregions in valgus knees (r = 0.87, OR 3.71). A significant negative correlation was found between JSW narrowing and area of subchondral bone in external lateral tibial subregion in valgus knees (r = −0.65, p < 0.01) and in external medial tibial subregion in varus knees (r = −0.77, p < 0.01). No statistically significant correlation was found in anterior and posterior subregions. Conclusion. SF radiographs can be potentially used for initial detection of cartilage degeneration as assessed by MRI in medial and lateral but not in anterior or posterior subregions. Cite this article: Bone Joint Res 2021;10(3):173–187

Aims. Post-traumatic osteoarthritis (PTOA) is a subset of osteoarthritis (OA). The gut microbiome is shown to be involved in OA. However, the effect of exercise on gut microbiome in PTOA remains elusive. Methods. A total of 18 eight-week Sprague-Dawley rats were assigned into three groups: Sham/sedentary (Sham/Sed), PTOA/sedentary (PTOA/Sed), and PTOA/treadmill-walking (PTOA/TW). PTOA model was induced by transection of the anterior cruciate ligament (ACLT) and the destabilization of the medial meniscus (DMM). Treadmill-walking (15 m/min, 30 min/d, five days/week for eight weeks) was employed in the PTOA/TW group. The response of cartilage, subchondral bone, serology, and gut microbiome and their correlations were assessed. Results. Eight-week treadmill-walking was effective at maintaining the integrity of cartilage-subchondral bone unit and reducing the elevated systematic inflammation factors and microbiome-derived metabolites. Furthermore, 16S ribosomal ribonucleic acid (rRNA) sequencing showed disease-relevant microbial shifts in PTOA animals, characterized by the decreased abundance of phylum TM7 and the increase of phylum Fusobacteria. At the genus level, the abundance of Lactobacillus, Turicibacter, Adlercreutzia, and Cetobacterium were increased in the PTOA animals, while the increase of Adlercreutzia and Cetobacterium was weakened as a response to exercise. The correlation analysis showed that genus Lactobacillus and Adlercreutzia were correlated to the structural OA phenotypes, while phylum Fusobacteria and genus Cetobacterium may contribute to the effects of exercise on the diminishment of serological inflammatory factors. Conclusion. Exercise is effective at maintaining the integrity of cartilage-subchondral bone unit, and the exercise-induced modification of disease-relevant microbial shifts is potentially involved in the mechanisms of exercise-induced amelioration of PTOA. Cite this article: Bone Joint Res 2022;11(4):214–225

Aims. The purpose of this study was to explore a simple and effective method of preparing human acellular amniotic membrane (HAAM) scaffolds, and explore the effect of HAAM scaffolds with juvenile cartilage fragments (JCFs) on osteochondral defects. Methods. HAAM scaffolds were constructed via trypsinization from fresh human amniotic membrane (HAM). The characteristics of the HAAM scaffolds were evaluated by haematoxylin and eosin (H&E) staining, picrosirius red staining, type II collagen immunostaining, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Human amniotic mesenchymal stem cells (hAMSCs) were isolated, and stemness was verified by multilineage differentiation. Then, third-generation (P3) hAMSCs were seeded on the HAAM scaffolds, and phalloidin staining and SEM were used to detect the growth of hAMSCs on the HAAM scaffolds. Osteochondral defects (diameter: 3.5 mm; depth: 3 mm) were created in the right patellar grooves of 20 New Zealand White rabbits. The rabbits were randomly divided into four groups: the control group (n = 5), the HAAM scaffolds group (n = 5), the JCFs group (n = 5), and the HAAM + JCFs group (n = 5). Macroscopic and histological assessments of the regenerated tissue were evaluated to validate the treatment results at 12 weeks. Results. In vitro, the HAAM scaffolds had a network structure and possessed abundant collagen. The HAAM scaffolds had good cytocompatibility, and hAMSCs grew well on the HAAM scaffolds. In vivo, the macroscopic scores of the HAAM + JCFs group were significantly higher than those of the other groups. In addition, histological assessments demonstrated that large amounts of hyaline-like cartilage formed in the osteochondral defects in the HAAM + JCFs group. Integration with surrounding normal cartilage and regeneration of subchondral bone in the HAAM + JCFs group were better than those in the other groups. Conclusion. HAAM scaffolds combined with JCFs promote the regenerative repair of osteochondral defects. Cite this article: Bone Joint Res 2022;11(6):349–361

Aims. Osteoarthritis (OA) is prevalent among the elderly and incurable. Intra-articular parathyroid hormone (PTH) ameliorated OA in papain-induced and anterior cruciate ligament transection-induced OA models; therefore, we hypothesized that PTH improved OA in a preclinical age-related OA model. Methods. Guinea pigs aged between six and seven months of age were randomized into control or treatment groups. Three- or four-month-old guinea pigs served as the young control group. The knees were administered 40 μl intra-articular injections of 10 nM PTH or vehicle once a week for three months. Their endurance as determined from time on the treadmill was evaluated before kill. Their tibial plateaus were analyzed using microcalculated tomography (μCT) and histological studies. Results. PTH increased the endurance on the treadmill test, preserved glycosaminoglycans, and reduced Osteoarthritis Research Society International score and chondrocyte apoptosis rate. No difference was observed in the subchondral plate bone density or metaphyseal trabecular bone volume and bone morphogenetic 2 protein staining. Conclusion. Subchondral bone is crucial in the initiation and progression of OA. Although previous studies have shown that subcutaneous PTH alleviates knee OA by improving subchondral and metaphyseal bone mass, we demonstrated that intra-articular PTH injections improved spontaneous OA by directly affecting the cartilage rather than the subchondral or metaphyseal bone in a preclinical age-related OA model. Cite this article: Bone Joint Res 2021;10(8):514–525

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

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

Aims. Local recurrence remains a challenging and common problem following curettage and joint-sparing surgery for giant cell tumour of bone (GCTB). We previously reported a 15% local recurrence rate at a median follow-up of 30 months in 20 patients with high-risk GCTB treated with neoadjuvant Denosumab. The aim of this study was to determine if this initial favourable outcome following the use of Denosumab was maintained with longer follow-up. Methods. Patients with GCTB of the limb considered high-risk for unsuccessful joint salvage, due to minimal periarticular and subchondral bone, large soft tissue mass, or pathological fracture, were treated with Denosumab followed by extended intralesional curettage with the goal of preserving the joint surface. Patients were followed for local recurrence, metastasis, and secondary sarcoma. Results. A total of 25 patients with a mean age of 33.8 years (18 to 67) with high-risk GCTB received median six cycles of Denosumab before surgery. Tumours occurred most commonly around the knee (17/25, 68%). The median follow-up was 57 months (interquartile range (IQR) 13 to 88). The joint was salvaged in 23 patients (92%). Two required knee arthroplasty due to intra-articular fracture and arthritis. Local recurrence developed in 11 patients (44%) at a mean of 32.5 months (3 to 75) following surgery, of whom four underwent repeat curettage and joint salvage. One patient developed secondary osteosarcoma and another benign GCT lung metastases. Conclusion. The use of Denosumab for joint salvage was associated with a higher than expected rate of local recurrence at 44%. Neoadjuvant Denosumab for joint-sparing procedures should be considered with caution in light of these results. Cite this article: Bone Joint J 2021;103-B(1):184–191

In order to clarify how intra-articular lesions influence the survival of a periacetabular osteotomy in patients with dysplasia of the hip, we performed an observational study of 121 patients (121 hips) who underwent a transposition osteotomy of the acetabulum combined with an arthroscopy. Their mean age was 40.2 years (13 to 64) and the mean follow-up was 9.9 years (2 to 18). Labral and cartilage degeneration tended to originate from the anterosuperior part of the acetabulum, followed by the femoral side. In all, eight hips (6.6%) had post-operative progression to Kellgren–Lawrence grade 4 changes, and these hips were associated with the following factors: moderate osteoarthritis, decreased width of the joint space, joint incongruity, and advanced intra-articular lesions (subchondral bone exposure in the cartilage and a full-thickness labral tear). Multivariate analysis indicated subchondral bone exposure on the femoral head as an independent risk factor for progression of osteoarthritis (p = 0.003). In hips with early stage osteoarthritis, femoral subchondral bone exposure was a risk factor for progression of the grade of osteoarthritis. . Although the outcome of transposition osteotomy of the acetabulum was satisfactory, post-operative progression of osteoarthritis occurred at a high rate in hips with advanced intra-articular lesions, particularly in those where the degenerative process had reached the point of femoral subchondral bone exposure

Aims. Altered alignment and biomechanics are thought to contribute to the progression of osteoarthritis (OA) in the native compartments after medial unicompartmental knee arthroplasty (UKA). The aim of this study was to evaluate the bone activity and remodelling in the lateral tibiofemoral and patellofemoral compartment after medial mobile-bearing UKA. Patients and Methods. In total, 24 patients (nine female, 15 male) with 25 medial Oxford UKAs (13 left, 12 right) were prospectively followed with sequential 99mTc-hydroxymethane diphosphonate single photon emission CT (SPECT)/CT preoperatively and at one and two years postoperatively, along with standard radiographs and clinical outcome scores. The mean patient age was 62 years (40 to 78) and the mean body mass index (BMI) was 29.7 kg/m2 (23.6 to 42.2). Mean osteoblastic activity was evaluated using a tracer localization scheme with volumes of interest (VOIs). Normalized mean tracer values were calculated as the ratio between the mean tracer activity in a VOI and background activity in the femoral diaphysis. Results. Significant reduction of normalized tracer activity was observed one year postoperatively in tibial and femoral VOIs adjacent to the joint line in the lateral compartment. Patellar VOIs and remaining femoral VOIs demonstrated a significant, diminished normalized tracer activity at final follow-up. Conclusion. The osteoblastic bone activity in the native compartments decreased significantly after treatment of medial end-stage OA with a UKA, implying reduced stress to the subchondral bone in the retained compartments after a UKA. Cite this article: Bone Joint J 2019;101-B:915–921

Aims. We analyzed the long-term outcomes of patients observed over ten years after resection en bloc and reconstruction with extracorporeal irradiated autografts. Patients and Methods. This retrospective study included 27 patients who underwent resection en bloc and reimplantation of an extracorporeal irradiated autograft. The mean patient age and follow-up period were 31.7 years (9 to 59) and 16.6 years (10.3 to 24.3), respectively. The most common diagnosis was osteosarcoma (n = 10), followed by chondrosarcoma (n = 6). The femur (n = 13) was the most frequently involved site, followed by the tibia (n = 7). There were inlay grafts in five patients, intercalary grafts in 15 patients, and osteoarticular grafts in seven patients. Functional outcome was evaluated with the Musculoskeletal Tumor Society (MSTS) scoring system. Results. There were no recurrences in the irradiated autograft and the autograft survived in 24 patients (88.9%). Major complications included nonunion (n = 9), subchondral bone collapse (n = 4), and deep infection (n = 4). Although 34 revision procedures were performed, 25 (73.5%) and four (11.8%) of these were performed less than five years and ten years after the initial surgery, respectively. The mean MSTS score at the last follow-up was 84.3% (33% to 100%). Conclusion. Considering long-term outcomes, extracorporeal irradiated autograft is an effective method of reconstruction for malignant musculoskeletal tumours. Cite this article: Bone Joint J 2019;101-B:1151–1159

Aims. The aim of this study was to evaluate antegrade autologous bone grafting with the preservation of articular cartilage in the treatment of symptomatic osteochondral lesions of the talus with subchondral cysts. Patients and Methods. The study involved seven men and five women; their mean age was 35.9 years (14 to 70). All lesions included full-thickness articular cartilage extending through subchondral bone and were associated with subchondral cysts. Medial lesions were exposed through an oblique medial malleolar osteotomy, and one lateral lesion was exposed by expanding an anterolateral arthroscopic portal. After refreshing the subchondral cyst, it was grafted with autologous cancellous bone from the distal tibial metaphysis. The fragments of cartilage were fixed with 5-0 nylon sutures to the surrounding cartilage. Function was assessed at a mean follow-up of 25.3 months (15 to 50), using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot outcome score. The radiological outcome was assessed using MRI and CT scans. Results. The mean AOFAS score improved from 65.7 (47 to 81) preoperatively to 92 (90 to 100) at final follow-up, with 100% patient satisfaction. The radiolucent area of the cysts almost disappeared on plain radiographs in all patients immediately after surgery, and there were no recurrences at the most recent follow-up. The medial malleolar screws were removed in seven patients, although none had symptoms. At this time, further arthroscopy was undertaken, when it was found that the mean International Cartilage Repair Society (ICRS) arthroscopic score represented near-normal cartilage. Conclusion. Autologous bone grafting with fixation of chondral fragments preserves the original cartilage in the short term, and could be considered in the treatment for adult patients with symptomatic osteochondral defect and subchondral cysts. Cite this article: Bone Joint J 2018;100-B:590–5

This systematic review examines the current literature regarding surgical techniques for restoring articular cartilage in the hip, from the older microfracture techniques involving perforation to the subchondral bone, to adaptations of this technique using nanofractures and scaffolds. This review discusses the autologous and allograft transfer systems and the autologous matrix-induced chondrogenesis (AMIC) technique, as well as a summary of the previously discussed techniques, which could become common practice for restoring articular cartilage, thus reducing the need for total hip arthroplasty. Using the British Medical Journal Grading of Recommendations, Assessment, Development and Evaluation (BMJ GRADE) system and Grade system. Comparison of the studies discussed shows that microfracture has the greatest quantity and quality of research, whereas the newer AMIC technique requires more research, but shows promise. Cite this article: W. E. Hotham, A. Malviya. A systematic review of surgical methods to restore articular cartilage in the hip. Bone Joint Res 2018;7:336–342. DOI: 10.1302/2046-3758.75.BJR-2017-0331

Objectives. Little is known about tissue changes underlying bone marrow lesions (BMLs) in non-weight-bearing joints with osteoarthritis (OA). Our aim was to characterize BMLs in OA of the hand using dynamic histomorphometry. We therefore quantified bone turnover and angiogenesis in subchondral bone at the base of the thumb, and compared the findings with control bone from hip OA. Methods. Patients with OA at the base of the thumb, or the hip, underwent preoperative MRI to assess BMLs, and tetracycline labelling to determine bone turnover. Three groups were compared: trapezium bones removed by trapeziectomy from patients with thumb base OA (n = 20); femoral heads with (n = 24); and those without (n = 9) BMLs obtained from patients with hip OA who underwent total hip arthroplasty. Results. All trapezium bones demonstrated MRI-defined BMLs. Compared with femoral heads without BMLs, the trapezia demonstrated significantly higher bone turnover (mean . sd. 0.2 (0.1) versus 0.01 (0.01) µm. 3. /µm. 2. /day), mineralizing surface (18.5% (13.1) versus 1.4% (1.3)) and vascularity (5.2% (1.1) versus 1.2% (0.6)). Femoral heads with BMLs exhibited higher bone turnover (0.3 (0.2) versus 0.2 (0.1) µm. 3. /µm. 2. /day), a higher mineralization rate (26.6% (10.6) versus 18.6% (11.9)) and greater trabecular thickness (301.3 µm (108) versus 163.6 µm (24.8)) than the trapezia. Conclusion. Bone turnover and angiogenesis were enhanced in BMLs of both the thumb base and hip OA, of which the latter exhibited the highest bone turnover. Thus, the increase in bone turnover in weight-bearing joints like the hip may be more pronounced than less mechanically loaded osteoarthritic joints demonstrating BMLs. The histological changes observed may explain the water signal from BMLs on MRI. Cite this article: M. Shabestari, N. J. Kise, M. A. Landin, S. Sesseng, J. C. Hellund, J. E. Reseland, E. F. Eriksen, I. K. Haugen. Enhanced angiogenesis and increased bone turnover characterize bone marrow lesions in osteoarthritis at the base of the thumb. Bone Joint Res 2018;7:406–413. DOI: 10.1302/2046-3758.76.BJR-2017-0083.R3

Osteochondritis Dissecans (OCD) is a condition for which the aetiology remains unknown. It affects subchondral bone and secondarily its overlying cartilage and is mostly found in the knee. It can occur in adults, but is generally identified when growth remains, when it is referred to as juvenile OCD. As the condition progresses, the affected subchondral bone separates from adjacent healthy bone, and can lead to demarcation and separation of its associated articular cartilage. Any symptoms which arise relate to the stage of the disease. Early disease without separation of the lesion results in pain. Separation of the lesion leads to mechanical symptoms and swelling and, in advanced cases, the formation of loose bodies. Early identification of OCD is essential as untreated OCD can lead to the premature degeneration of the joint, whereas appropriate treatment can halt the disease process and lead to healing. Establishing the stability of the lesion is a key part of providing the correct treatment. Stable lesions, particularly in juvenile patients, have greater propensity to heal with non-surgical treatment, whereas unstable or displaced lesions usually require surgical management. This article discusses the aetiology, clinical presentation and prognosis of OCD in the knee. It presents an algorithm for treatment, which aims to promote healing of native hyaline cartilage and to ensure joint congruity. Take home message: Although there is no clear consensus as to the best treatment of OCD, every attempt should be made to retain the osteochondral fragment when possible as, with a careful surgical technique, there is potential for healing even in chronic lesions. Cite this article: Bone Joint J 2016;98-B:723–9

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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.

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The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI).

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The preventive effects of bisphosphonates on articular cartilage in non-arthritic joints are unclear. This study aimed to investigate the effects of oral bisphosphonates on the rate of joint space narrowing in the non-arthritic hip.

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Arthroscopic microfracture is a conventional form of treatment for patients with osteochondritis of the talus, involving an area of < 1.5 cm². However, some patients have persistent pain and limitation of movement in the early postoperative period. No studies have investigated the combined treatment of microfracture and shortwave treatment in these patients. The aim of this prospective single-centre, randomized, double-blind, placebo-controlled trial was to compare the outcome in patients treated with arthroscopic microfracture combined with radial extracorporeal shockwave therapy (rESWT) and arthroscopic microfracture alone, in patients with ostechondritis of the talus.

Cite this article: Bone Joint Res 2023;12(10):654–656.

Aims

Giant cell tumour of bone (GCTB) is a locally aggressive lesion that is difficult to treat as salvaging the joint can be associated with a high rate of local recurrence (LR). We evaluated the risk factors for tumour relapse after treatment of a GCTB of the limbs.