Bone regeneration and repair are crucial to ambulation and quality of life. Factors such as poor general health, serious medical comorbidities, chronic inflammation, and ageing can lead to delayed healing and nonunion of fractures, and persistent bone defects. Bioengineering strategies to heal bone often involve grafting of autologous bone marrow aspirate concentrate (BMAC) or mesenchymal stem cells (MSCs) with biocompatible scaffolds. While BMAC shows promise, variability in its efficacy exists due to discrepancies in MSC concentration and robustness, and immune cell composition. Understanding the mechanisms by which macrophages and lymphocytes – the main cellular components in BMAC – interact with MSCs could suggest novel strategies to enhance bone healing. Macrophages are polarized into pro-inflammatory (M1) or anti-inflammatory (M2) phenotypes, and influence cell metabolism and tissue regeneration via the secretion of cytokines and other factors. T cells, especially helper T1 (Th1) and Th17, promote inflammation and osteoclastogenesis, whereas Th2 and regulatory T (Treg) cells have anti-inflammatory pro-reconstructive effects, thereby supporting osteogenesis. Crosstalk among macrophages, T cells, and MSCs affects the bone microenvironment and regulates the local immune response. Manipulating the proportion and interactions of these cells presents an opportunity to alter the local regenerative capacity of bone, which potentially could enhance clinical outcomes.

Cite this article: Bone Joint Res 2024;13(9):462–473.

Aims

Trained immunity confers non-specific protection against various types of infectious diseases, including bone and joint infection. Platelets are active participants in the immune response to pathogens and foreign substances, but their role in trained immunity remains elusive.

As our understanding of hip function and disease improves, it is evident that the acetabular fossa has received little attention, despite it comprising over half of the acetabulum’s surface area and showing the first signs of degeneration. The fossa’s function is expected to be more than augmenting static stability with the ligamentum teres and being a templating landmark in arthroplasty. Indeed, the fossa, which is almost mature at 16 weeks of intrauterine development, plays a key role in hip development, enabling its nutrition through vascularization and synovial fluid, as well as the influx of chondrogenic stem/progenitor cells that build articular cartilage. The pulvinar, a fibrofatty tissue in the fossa, has the same developmental origin as the synovium and articular cartilage and is a biologically active area. Its unique anatomy allows for homogeneous distribution of the axial loads into the joint. It is composed of intra-articular adipose tissue (IAAT), which has adipocytes, fibroblasts, leucocytes, and abundant mast cells, which participate in the inflammatory cascade after an insult to the joint. Hence, the fossa and pulvinar should be considered in decision-making and surgical outcomes in hip preservation surgery, not only for their size, shape, and extent, but also for their biological capacity as a source of cytokines, immune cells, and chondrogenic stem cells.

Cite this article: Bone Joint Res 2020;9(12):857–869.

Aims

The efficacy and safety of intrawound vancomycin for preventing surgical site infection in primary hip and knee arthroplasty is uncertain.

Osteoarthritis (OA) is no longer considered a cartilage-centric disease with remodelling of other joint tissues now recognized. While understudied, entheseal pathology is considered a secondary OA feature. A pivotal role for proteinase-activated receptor 2 (PAR2) in OA has been demonstrated previously in cartilage and subchondral bone at early time points, however the entheseal role of PAR2 has not been reported. OA was induced by destabilization of the medial meniscus (DMM) in wild type (WT) and PAR2 deficient (KO) animals. At 4 weeks and one year post surgery, knee joints were harvested for histological analysis. Medial collateral ligament (MCL) width was measured by 2D planimetry analysis. Immunohistochemistry was used to characterize the MCL and anterior cruciate ligament (ACL). Data were expressed as mean±SEM (n=4–6/group) and analysed using Student's t-test, with p<0.05 as the criterion of significance. MCL width increased between 4 weeks and 1 year in WT DMM (0.24 ±0.07 vs 0.40 ±0.008mm respectively, p<0.001). Interestingly, a significant reduction in MCL was observed in KO compared with WT at 1 year (0.23 ±0.005 vs 0.40 ±0.008mm respectively, p <0.001) post-DMM. Further characterization of DMM WT MCL and ACL at 4 weeks showed the presence of F4/80. +. cells in addition to IL-33 and histamine. At one year post-surgery, a cellular infiltrate was observed in MCL DMM WT but absent in KO mice. Histological evaluation revealed an absence of F4/80. +. cells but the presence of a PAR2. +. population, subsequently identified as hypertrophic-like chondrocytes (RUNX2) and chondrocytes-like cells (SOX9). Deletion of PAR2 affords long-term protection against ligament remodelling and demonstrates a critical role for this receptor in both OA joint pathology and ligament injuries. While PAR2 appears to be a credible therapeutic target in OA entheseal pathology, further understanding of the molecular mechanism regulated by this receptor will be required

Aims

Animal models have been developed that allow simulation of post-traumatic joint contracture. One such model involves contracture-forming surgery followed by surgical capsular release. This model allows testing of antifibrotic agents, such as rosiglitazone.

The purpose of this study was to evaluate the expression of acid-sensing ion channels (ASICs) in the capsule and synovial fluid of patients with frozen shoulder. Capsular tissue and synovial fluid were obtained from 18 patients with idiopathic frozen shoulder (FS group) and 18 patients with instability of the shoulder (control group). The expressions of ASIC1, ASIC2, and ASIC3 in the capsule were determined using the reverse transcriptase-polymerase chain reaction, immunoblot analysis, and immunohistochemistry (IHC). The concentrations in synovial fluid were evaluated using an enzyme-linked immunosorbent assay.

The mRNA expression of ASIC1, ASIC2 and ASIC3 in the capsule were significantly increased in the FS group compared with the control group. The protein levels of these three ASICs were also increased. The increased expressions were confirmed by IHC. Of the ASICs, ASIC3 showed the greatest increase in both mRNA and levels of expression compared with the control group. The levels of ASIC1 and ASIC3 in synovial fluid were significantly increased in the FS group.

This study suggests that ASICs may play a role as mediators of inflammatory pain and be involved in the pathogenesis of frozen shoulder.

Cite this article: Bone Joint J 2015;97-B:824–9.

Purpose. Congenital insensitivity to pain is a rare autosomal recessive condition that leads to varying degrees of sensory and autonomic neuropathy. The aim of the study was to explore the common orthopaedic presentations of congenital insensitivity to pain and provide guidance on their treatment and complications. Methods. This study presents the results of fifteen patients with congenital insensitivity to pain, which were referred and treated at our supra-regional referral centre. Intradermal histamine tests and quantitative sweat tests were performed on all fifteen patients. Results. The average age of presentation was 13.2 years (range, two to 28 years). Eight patients presented with Charcot arthropathies and joint dislocations, which involved the foot/ankle (n=4), knee (n=2) or spine (n=2). Four patients presented with fractures or avascular necrosis affecting the tarsal bones and three patients presented with recurrent infections of the lower limbs. Patient education regarding appropriate shoe ware, pedal hygiene, periods of non-weight bearing, spinal bracing and close follow-up within the multi-disciplinary team was the mainstay of treatment. Patients with infection underwent cultures, aspiration, magnetic resonance imaging and treatment with antibiotics. Only one patient required joint washout for septic arthritis of the ankle. Conclusions. Congenital insensitivity to pain presents with both acute and chronic pathology affecting the weight-bearing joints. Treatment should be aimed at off-loading the pressure on these joints and preventing the development of further complications. Surgical intervention should be reserved for patients not responding to conservative treatment or those requiring debridement/washout for extensive infection

Our understanding of the origin of hip pain in degenerative disorders of the hip, including primary osteoarthritis, avascular necrosis and femoroacetabular impingement (FAI), is limited. We undertook a histological investigation of the nociceptive innervation of the acetabular labrum, ligamentum teres and capsule of the hip, in order to prove pain- and proprioceptive-associated marker expression. These structures were isolated from 57 patients who had undergone elective hip surgery (44 labral samples, 33 ligamentum teres specimens, 34 capsular samples; in 19 patients all three structures were harvested). A total of 15 000 histological sections were prepared that were investigated immunohistochemically for the presence of protein S-100, 68 kDa neurofilament, neuropeptide Y, nociceptin and substance P. The tissues were evaluated in six representative areas.

Within the labrum, pain-associated free nerve ending expression was located predominantly at its base, decreasing in the periphery. In contrast, the distribution within the ligamentum teres showed a high local concentration in the centre. The hip capsule had an almost homogeneous marker expression in all investigated areas.

This study showed characteristic distribution profiles of nociceptive and pain-related nerve fibres, which may help in understanding the origin of hip pain.

Cite this article: Bone Joint J 2013;95-B:770–6.

Introduction

The pathogenesis of rotator cuff disease (RCD) is complex and not fully understood. This systematic review set out to summarise the histological and molecular changes that occur throughout the spectrum of RCD.

Background: Polymethylmethacrylate (PMMA) is a potent stimulant of inflammatory response. This study investigated the role of Prostaglandin E2 (PGE2), Platelet activating factor (PAF) and histamine and their specific antagonists in bone changes. Materials: 120 white-male-wistar rats were divided into ten groups. Using sterile technique, a 2mm drill hole was made in the tibia 1cm distal to the knee joint bilaterally. The left tibia was filled with Simplex particulate cement polymer (PMMA) and the right tibia was used as control. The first nine groups respectively received terfenadine 1mg/kg, 10mg/kg and 25mg/kg, alprazolam 0.08mg/kg, 0.32mg/kg and 0.64mg/kg, and naproxen 1mg/kg, 5mg/kg and 25mg/kg; however, the tenth group received no drug and served as control. The animals were killed after 16 weeks and implant areas were harvested aseptically and studied by one pathologist. Results: Our study revealed that the cellular reaction in the left side was statistically more than the right one in all cases (p< 0.05). Also, a significant decrease in histiocytes and giant cells was seen just in those groups that had received 10mg/kg and 25mg/kg of terfenadine, 0.32mg/kg and 0.64mg/kg of alprazolam and 5mg/kg and 25mg/kg of naproxen (P< 0.05) while administration of 1mg/kg naproxen resulted in significant decrease only in giant cells (P< 0.05) but not in histiocytes. Discussion: Previous studies have suggested that particulate debris, PGE2 production and inflammatory response are associated with arthroplasty loosening. This experiment has demonstrated that the increased cellular reaction by the membrane surrounding particulate cement polymer can be suppressed by administration of PGE2, PAF and histamine specific inhibitors. The use of these agents may be indicated in retarding the bone loss associated with early prosthetic loosening

Introduction: Bradykinin (BK) exerts its effects directly via B2 receptors but also indirectly through release of factors such as prostaglandins, cytokines, or histamine. During in vitro and preclinical in vivo studies, the B2 receptor inhibitor icatibant (ITB) has been shown to be a potent inhibitor of BK effects. Recently it has been found that a single injection of 90 μg of ITB significantly reduced pain in patients with knee OA, and this effect lasted for about 1 week. The aim of the present study was to determine whether ITB, by multiple dosing, may exert long-lasting clinically relevant effects on OA pain. Objectives:. To compare the onset, extent and duration of pain relief (pain during activity, at rest and at night) in the affected knee between 2 dose groups of ITB and placebo by using a visual analogue scale (VAS). To compare ITB and placebo for safety and the efficacy variables: Western Ontario McMaster Universities OA index (WOMAC), and time until need of rescue medication. Study design: Randomised, double-blind, placebo-controlled, 3-arm, parallel-group, 12-week multi-centre study to compare the effect of intra-articular injections of 2 doses of ITB (500 μg and 2000 μg) and placebo in patients with symptomatic unilateral knee OA. Subjects were treated 3 times in weekly intervals and then followed-up for 10 weeks. Assessments of pain and intake of rescue medication was followed with an electronic patient diary on a daily basis. Functional assessment of the affected knee joint was performed by answering the WOMAC questionnaire at several visits following the last injection. Statistical analysis included the Chi-square test, differences in means, Wilcoxon-test, the trapezoid rule and Kaplan-Meier curves, using analysis of variance without and with covariates (ANOVA, ANCOVA). Results: 340 subjects were screened, and 266 were randomised and treated: 90 with placebo, 86 with 500 μg and 90 with 2000 μg ITB. Treatment-emergent adverse events were experienced by 13 subjects treated with placebo, 8 with 500 μg and 17 treated with 2000 μg ITB. After 3 injections, long-lasting reduction in pain up to 12 weeks after start of treatment could be observed in all treatment groups. Onset of pain relief by _ 10 units was fast and had been reported already 4 hours after start of injection. Both ITB groups consistently demonstrated greater effects on pain when compared to the placebo group; however, there was no difference between the 500 μg and 2000 μg dose groups. Conclusion: The outcome of the present study demonstrates ITB as an analgesic with fast onset and long-lasting pain relief, which could be differentiated against placebo. Its extent of pain relief, together with its excellent safety profile, qualifies ITB as a promising alternative for intervention in acute and chronic pain

Several aspects of the management of an orthopaedic surgical patient are not directly related to the surgical technique but are nevertheless essential for a successful outcome. Blood management is one of these. This paper considers the various strategies available for the management of blood loss in patients undergoing orthopaedic and trauma surgery.

Avascular necrosis of the femoral head creates considerable morbidity in successful renal transplant recipients who are generally young and expect active lifestyles. Total hip replacement is considered the treatment of choice in these patients, but surgeons may be wary because of a supposed increase in the risk of infection and other complications.

A review of the literature reveals that cemented hip arthroplasty provides good to excellent functional outcomes for renal transplant patients. Most authors have found that the risk of infection is not increased despite chronic immunosuppression, but the rates of general complications are and should be anticipated and treated. There is a high rate of early failure in these patients because of their young age and diffuse osteopenia as a result of secondary hyperparathyroidism related to the underlying renal disease and chronic steroid use. Recent studies have found that despite decreased bone stock in these patients, porous-coated prostheses are not contraindicated.

Systemic mastocytosis is a rare condition that often involves the bone marrow. We report the case of a patient with systemic mastocytosis who underwent total hip replacement. Technical difficulties encountered during the procedure included a narrow medullary canal and abnormally hard bone, later confirmed by laboratory measurements. Follow-up at five years showed a good clinical and radiological outcome.

Introduction: Histamine is an integral mediator following traumatic injury. Histamine-2 receptors have previously been identified on lymphocytes and monocytes. Materials and methods: Two rodent models (1) Bilateral femoral fracture and intramedullary nailing, with resulting indirect lung injury (n=30). (2) In vivo model of orthopaedic implant contaminated by Staphylococcus epidermidis (n=36). Animals were randomised to receive ranitidine or placebo (saline). Results: Markers of lung injury (MPO activity, BAL proteins and wet:dry ratios) increased 24 hours following bilateral femoral fracture, but were reduced if ranitidine was administered systemically after the injury. Production of Th-1 cytokines was blocked by ranitidine, whilst Th-2 cytokine production remained unaffected by ranitidine. These suggest an anti-inflammatory effect of ranitidine, blocking the early (Th-1) pro-inflammatory response following major injury. Ranitidine’s effect on implant infection rates showed higher rates (44% versus 17%, relative risk 1.8 (95% CI 1.0 to 3.3)) when systemic ranitidine was delivered peri-operatively, suggesting an immunosuppressive effect. Conclusions: The findings highlight the complex balance in vivo, a double-edged sword: the risk of increasing implant infection versus reducing indirect lung injury following major injury. The administration of ranitidine in major trauma patients with severe pro-inflammatory responses may block and reduce early multi-organ dysfunction and improve survival. However, owing to infection, the peri-operative administration of ranitidine should be avoided in elective cases

Background and aim: Clear cell sarcoma is a rare tumor with melanocytic features and is associated with tendons and aponeuroses. 18 cases were registered between 1986 and 1996 in the Scandinavian Sarcoma Group central registry. The aim was to investigate if histamine enhances the antitumor effect of dacarbazine (DTIC) and docetaxel. Methods: Human clear cell sarcoma tumor tissue was maintained by serial s.c. transplantations in nude mice. DTIC (200mg/kg, i.p.) 3 times with an interval of 2 days, docetaxel (20 mg/kg, i.p.) single dose and histamine (4 mg/kg, s.c.) daily, 5 days per week was administered in tumorbearing nude mice. DTIC and docetaxel was given separately or in combination with histamine. The tumor volumes were compared with a control group (given saline i.p.). The antitumor effect is considered signiþcant when Treatment/Control-ratio ≤ 0.4 Results: In the DTIC group the lowest TC-ratio was noted at day 21 (0.54) and in the histamine-DTIC group (0.37). Corrresponding results were 0.39 in the docetaxel-group and 0.33 in the combination docetaxel-histamine at day 13. The TC-ratio was reduced at all measuring occasions when histamine was given in adjunction with DTIC and docetaxel. Conclusions: Histamine seems to enhance the antitumor effect of dacarbazine and docetaxel in this clear cell sarcoma tumor model