Nitric oxide is a free radical which in vivo is solely produced during the conversion of the amino acid arginine into citrulline by nitric oxide synthase enzymes. Recently, the importance of nitric oxide on inflammation and bone metabolism has been investigated. However, the knowledge regarding possible in vitro effects of arginine supplementation on chondrogenic differentiation is limited. ATDC5, a cell line which is derived from mouse teratocarcinoma cells and which is characterized as chondrogenic cell line, were proliferated in Dulbecco's Modified Eagle Medium (DMEM)/F12 and subsequently differentiated in proliferation medium supplemented with insulin, transferrin and sodium-selenite and where arginine was added in four different concentrations (0, 7.5, 15 and 30 mM). Samples were harvested after 7 or 10 days and were stored at −80 °C for subsequent RNA isolation for qPCR analysis. To determine chondrogenic differentiation, Alcian Blue staining was performed to stain the proteoglycan aggrecan, which is secreted by differentiated ATDC5 cells. All measurements were performed in triplo. Alcian Blue staining showed a qualitative increase of proteoglycan aggrecan secretion in differentiated ATDC5 cells after treatment with 7 and 15 mM arginine, with additional increased expression of ColII, ColX, Bmp4 and Bmp6. Treatment with 30 mM arginine inhibited chondrogenic differentiation and expression of aforementioned genes, however, Cox-2 and Vegfa gene expression were increased in these samples. Bmp7 was not significantly expressed in any experimental condition. The obtained results are suggestive for a dose-dependent effect of arginine supplementation on chondrogenic differentiation and associated gene expression, with 7.5 and 15 mM as most optimal concentrations and implications for apoptosis after incubation with 30 mM arginine. A future recommendation would be to investigate the effects of citrulline in a similar experiment, as this shows even more promising results to enhance the nitric oxide metabolism in sepsis and bone healing

Fracture related infections (FRI) are debilitating complications of musculoskeletal trauma surgery that can result in permanent functional loss or amputation. This study aims to determine risk factors associated with FRI treatment failure, allowing clinicians to optimise them prior to treatment and identify patients at higher risk. A major trauma centre database was retrospectively reviewed over a six-year period. Of the 102 patients identified with a FRI (66 male, 36 female), 29.4% (n=30) had acute infections (onset <6 weeks post-injury), 34.3% (n=35) had an open fracture. Open fractures were classified using Gustilo-Anderson (GA) classification (type 2:n=6, type 3A:n=16, type 3B:n=10, type 3C:n=3). Patients with periprosthetic infections of the hip and knee joint, those without prior fracture fixation, soft tissue infections, diabetic foot ulcers, pressure sore infections, patients who died within one month of injury, <12 months follow-up were excluded. FRI treatment failure was defined as either infection recurrence, non-union, or amputation. Lifestyle, clinical, and intra-operative data were documented via retrospective review of medical records. Factors with a P-value of p<0.05 in univariate analysis were included in a stepwise multivariate logistic regression model. FRI treatment failure was encountered in 35.3% (n=36). The most common FRI site was the femoral shaft (16.7%; n=17), and 15.7% (n=16) presented with signs of systemic sepsis. 20.6% (n=21) had recurrent infection, 9.8% (n=10) had non-union, and 4.9% (n=5) required an amputation. The mean age at injury was 49.71 years old. Regarding cardiovascular risk factors, 37 patients were current smokers (36.3%), 31 patients were diabetics (30.4%), and 32 patients (31.4%) were obese (BMI≥30.0). Average follow-up time was 2.37 (range: 1.04-5.14) years. Risk factors for FRI treatment failure were BMI>30, GA type 3c, and implant retention. Given that FRI treatment in 35.3% (36/102) ended up in failure, clinicians need to take into account the predictive variables analysed in this study, and implement a multidisciplinary team approach to optimise these factors. This study could aid clinicians to redirect efforts to improve high risk patient management, and prompt future studies to trial adjuvant technologies for patients at higher risk of failure

The number of revision knee arthroplasties performed is projected to rise dramatically in the coming years. Primary knee arthroplasties are also being performed in younger patients increasing the likelihood of multiple revision procedures. Reconstruction can be challenging with bone stock deficiencies and ligament incompetence. The aim of this study was to present our results of revision total knee arthroplasty using metaphyseal sleeve components to aid reconstruction. Sixty seven patients underwent revision total knee arthroplasty between September 2005 and November 2010 using metaphyseal sleeves. There were thirty one male and thirty six female patients. The indication for revision was aseptic loosening in thirty nine, sepsis in fifteen, malalignment in eight and instability in five patients. Thirty four patients had tibial sleeves, thirty patients had both tibial and femoral sleeves and three patients had femoral sleeves during revision. The patients were followed up for a mean of 32 months (Range 12–60) with outcome data collected prospectively. The mean revised oxford knee scores for the patients improved from 15 (Range 2 to 29) preoperatively to 33 (Range 20 to 45) postoperatively. Mean arc of flexion following revision was 87 degrees (Range 55 to 120). Seventy six percent of patients were satisfied or very satisfied with the result of the revision surgery. There have been no radiographic complications specific to the sleeves and no re-operations. There has been one recurrence of infection in a patient revised for sepsis. This has been managed with suppressive antibiotics due to patient co-morbidities. Metaphyseal sleeves are an effective adjunct in revision knee arthroplasty. We have had good results with their use. To our knowledge no larger series has been presented or published

Background. Metal-on-metal (MoM) hip arthroplasty has been associated with adverse reactions including pseudotumours, and osteolysis. Tissues surrounding failed MoM hip implants are often infiltrated by inflammatory cells such as monocytes and neutrophils. The mechanisms by which these cells are recruited to the tissues remain unclear. Cobalt from MoM implants activates Toll-like receptor 4 (TLR4), an immune cell surface receptor usually responsible for recognition of bacteria and prevention of sepsis. Activation by bacteria leads to secretion of pro-inflammatory cytokines which guide other immune cells to the site of inflammation. The effect of cobalt on this response is unknown and therefore this study aims to determine the effect of cobalt-mediated TLR4 activation on the migration of inflammatory cells. Methods. A human macrophage cell line (MonoMac 6) was stimulated with a physiologically-relevant range of cobalt ions for 24h with or without pre-treatment with a TLR4 antagonist. Conditioned media was collected and used in a trans-well migration assay to determine its effect on migration of primary monocytes and neutrophils isolated from whole human blood. Migrated cells were stained with haematoxylin and counted at ×40 magnification. Results. Conditioned media from cobalt-treated macrophages caused elevated monocyte and neutrophil migration across all concentrations. Pre-treatment of MonoMac 6 cells with a TLR4 antagonist significantly decreased the response. This suggests that the cytokine profile produced in response to cobalt-mediated TLR4 activation is pro-migratory for immune cells. Conclusions. Cobalt activation of TLR4 leads to secretion of inflammatory cytokines that attract monocytes and neutrophils. This work highlights a potential mechanism by which cobalt ions from failed MoM joints could be involved in inflammatory cell recruitment to the surrounding tissues. The TLR4 signalling pathway represents an exciting area for further investigation as a therapeutic target in the prevention of adverse reactions to cobalt ions. Disclosure. This work is funded by DePuy Synthes Ltd and the Newcastle NIHR Biomedical Research Centre

Background. Post-traumatic immunosuppression (PTI) after surgery increases vulnerability to nosocomial infections, sepsis, and death. Knee arthroplasty offers a sterile clinical model to characterise PTI and explore its underlying mechanisms. Methods. This prospective non-randomised cohort study of primary total knee arthroplasty was approved by the Local Ethics Committee. Exclusion criteria included revision-arthroplasty, pre-existing infections, blood-transfusions, malignancy, and auto-immune disease. 48 recruited patients fell into two groups, the first received unwashed anti-coagulated autologous salvaged blood transfusions after surgery (ASBT cohort, n=25). The second received no salvaged blood transfusions (NSBT cohort, n=18). Venous blood was sampled pre-operatively and within 3–7 days post-operatively. Salvaged blood was sampled at one and six hours post-operatively. Biomarkers of immune status included: interleukins (IL) or cytokines (x15), chemokines (x3), Damage-Associated-Molecular-Patterns (DAMPS) (x5), anti-microbial proteins (x3), CD24, and Sialic-acid-binding-Immunoglobulin-type-Lectin-10 (Siglec-10). Results were expressed as fold-change over pre-operative values. Only significant changes are described. Results. Certain biomarkers associated with sterile trauma were common to all 43 patients, including supra-normal: IL-6, IL-1-Receptor-Antagonist, IL-8, Heat-Shock-Protein-70 (HSP70), Calprotectin, CD24 and Siglec-10. But, whereas in NSBT patients post-operative pro-inflammatory biomarkers were sub-normal consistent with PTI, they were supra-normal in ASBT patients implying its reversal. These PTI-biomarkers included: IL-1β, IL-2, IL-17A, Interferon-gamma (IFN-γ), Tumour-Necrosis-Factor-alpha (TNF-α), and Annexin-A2. Reversal of PTI by salvaged blood was further endorsed in ASBT by sub-normal levels of the anti-inflammatory biomarkers: IL-4, IL-5, IL-10, and IL-13. Salvaged blood analyses revealed sustained supra-normal levels of DAMPs, CD24 and Siglec-10; and increasingly elevated levels of cytokines and chemokines during the six hour collection period. Interestingly, plasma CD24, Siglec-10, HSP70 and Calprotectin levels were significantly correlated, implying physical association within the circulation. Conclusions. Several anti-inflammatory processes triggered by traumatised tissue induce systemic PTI, thereby increasing vulnerability to infections. Reversal of PTI by re-infusion of anti-coagulated salvaged blood suggests a novel source of immuno-stimulants

We describe a case series using calcium sulphate bio composite with antibiotics (Cerament/Stimulan) in treating infected metalwork in the lower limb. Eight patients aged 22–74 (7 males, 1 female) presented with clinical evidence of infected limb metal work from previous orthopaedic surgery. Metal work removal with application of either cerement in 5 cases (10–20ml including 175mg–350mg gentamycin) or stimulan in 3 cases (10–20ml including either 1g vancomycin or clindamycin 1.2g or 100mg tigecycline) into the site was performed. Supplemental systemic antibiotic therapy (oral/intravenous) was instituted based on intraoperative tissue culture and sensitivity. Four patients had infected ankle metalwork, 2 patients infected distal tibial metalwork and 2 had infected external fixators. Metal work was removed in all cases. The mean pre operative CRP was 15.8mg/l (range 1–56mg/l). The mean postoperative CRP at 1 month was 20.5mg/l (range 2–98mg/l). The mean pre op WCC was 7.9×10. 9. (range 4.7–10.5 ×10. 9. ). Mean post op WCC at 1 month was 7.1×10. 9. (range 5.0–9.2×10. 9. ). The organisms cultured included enterobacter, staphylococcus aureus, staphylococcus epidermidis, staphylococcus cohnii, stenotrophomonas, acinetobacter, group B streptococcus, enterococcus and escherichia coli. No additional procedures were required in any case. All surgical wounds went on to heal uneventfully. Infection control and union was achieved both clinically and radiologically in all cases. Our results support the use of a calcium sulphate bio composite with antibiotic as an adjuvant for effective local infection control in cases with implant related bone sepsis. The technique is well tolerated with no systemic or local side effects. We believe that implant removal, debridement and local antibiotic delivery can minimise the need for prolonged systemic antibiotic therapy in such cases

The implementation of knee arthrodesis has become synonymous with limb salvage in the presence of chronic sepsis and bone loss around the knee. This can be seen in failed trauma surgery or knee arthroplasty as an alternative to trans-femoral amputation. There is no prior literature assessing which factors affect knee arthrodesis using external fixation devices. Sixteen consecutive patients (four women and twelve men) made up of eleven infected knee implants, three internal fixations of the tibial following fractured tibial plateau as well as 2 infected native joints were identified. The mean age at initial surgery was 56 years (range 25 to 82 years). All procedures were performed under the direct supervision of the limb reconstruction teams using a standard protocol with either a Taylor spatial frame or Ilizarov frame. The patient records, microbiology results and radiographs of all patients who underwent knee arthrodesis at this institution between 1999 and 2010 were reviewed. Of the 16 patients in this study knee fusion occurred in eleven patients (69%). The five patients where arthrodesis failed all had significant bone loss on the pre-operative radiographs and confirmed at surgery. We found a relationship between a significant infection of the knee with MRSA and failure to fuse. Three of the five patients had MRSA isolated from inside the knee at some stage during their treatment. The five patients where fusion failed were on average older (mean age 63 years against 51 years) and had more extensive bone loss. Those who failed to fuse had more co-morbidities. We would conclude that where there is little or no bone loss, arthrodesis of the knee can be reliably achieved with the use of circular frame fixation. A greater number of negative factors also prolongs the amount of time spent in the external fixator. The presence of significant bone loss, infection, increased age and multiple co-morbidities requires careful evaluation and consideration of trans-femoral amputation as an alternative

We compared the postoperative wound discharge rates and 3 months clinical results of three types of wound closure and dressing – 2-octylcyanoacrylate with Opstie (G+O), 2-octylcyanoacrylate with Tegaderm (G+T), and Opsite without 2-octylcyanoacrylate (O) in patients having primary total hip arthroplasty. We randomised 141 patients scheduled for primary total hip arthroplasty into 3 arms of this study- G+O, G+T, or O. The extent of wound discharge was recorded on a diagrammatic representation of the dressing in situ on paper and graded each day. Dressings were left in-situ provided the extent of wound discharge allowed for this. The patient was clinically reviewed at 3 months to assess their scar length, cosmesis, scar discomfort, and evidence of superficial or deep wound sepsis. A greater number of patients dressings remained dry on day 1 postoperatively in the two groups with 2-octylcyanoacrylate compared to the no glue group p=0.001. G+T group had a significantly lower proportion of patients with increased leakage of wounds on 2. nd. postoperative day p=0.044. At 3 months review, there was no statistical difference in the Hollander score or scar discomfort. In patients who have had primary total hip arthroplasty, usage of 2-octylcyanoacrylate for wound closure along with Tegaderm dressing reduces wound discharge. The same effect is not noted in glue with Opsite group. Whilst dressing changes required in the non-glue group compared from the two glue groups did not reach statistical significance, this may have clinical relevance for patients and nursing staff. No effect on postoperative length of stay, or wound complications was noted

Deep infection represents one of the most devastating complications of total knee arthroplasty. Commonly implicated organisms are gram positive bacteria such as staphylococcus aureus, staphylococcus epidermidis and group B streptococcus. Occasionally, infection may be caused by rare organisms, particularly in the immunocompromised host. We present a case of infected total knee arthroplasty in a penicillin allergic patient, caused by Pasteurella multocida, 13 weeks after the initial surgery. This was treated by open debridement and change of insert as well as aggressive antibiotic therapy. The patient admitted contact with a cat and three dogs at home. Pasteurella multocida is a facultatively anaerobic gram negative coccobacillus. It is a commensal in the nasopharygeal tract of domestic pets such as cats and dogs. Human infection can often be attributed to a bite or scratch. Prosthetic joint infection caused by Pasteurella is uncommon. Only a few cases have been reported in the literature. Our case has several learning points: (1) It is very important to definitively identify Pasteurella because standard therapy for prosthetic joint infection (e.g. flucloxacillin or vancomycin) is not optimal for this species.(2) Pasteurella are susceptible to penicillin, but the optimal antibiotic therapy for infections in patients allergic to beta lactam antibiotics is uncertain. A combination of ciprofloxacin and linezolid is recommended. (3) There is no consensus regarding appropriate management. There are reports of washout and antibiotic therapy alone, single and two stage revision procedures. In our case, at five months follow up, open debridement and change of insert along with antibiotic treatment appears to have been effective, although more long term follow up is required. (4)Post arthroplasty, all patients with pets at home should be advised to seek medical attention following any bite or scratch so that timely prophylaxis can be administered before sepsis becomes deep-seated

Introduction. 20 cases of bone defect have been treated by the induced membrane technique avoiding allograft, microsurgery and amputation. Material and Methods. 9 cases of long bone defect (humerus and 2 bones arm) and 11 cases of bone defct at the hand have been included in this multicentric prospective study (3 centers). 11 cases were traumatic, 7 cases were septic non union and 2 cases were tumor. At hand level's bone reached at least one phalanx, and for long bone the mean defect was 5cm (3–11). All cases were treated by the induced membrane technique which consists in stable fixation, flap if necessary and in filling the void created by the bone defect by a cement spacer (PMMA). This technique needs a second stage procedure at the 2. nd. month where the cement is removed and the void is filled by cancellous bone. The key point of this induced membrane technique is to respect the foreign body membane which appeared around the cement spacer and which create a biologic chamber after the second time. Bone union was evaluated prospectively in each case by an surgeon not involved in the treatment by Xray and CT scan. Failure was defined as a non union at 1 year, or an uncontrolled sepsis at 1 month. Results. 3 cases failed to achieve bone union, 2 at hand level and 1 for long bone. No septic complications occured and all septic cases werre stopped. In 14 cases bone union was achieved with a delay of 5 months (1, 5–12). 2 biopsies allowed to proove us that osteoid tissue was created by the technic. At hand level all fingers have included. At shoulder and elbow level, function reached 75% of motion than controlateral side. Discussion. Masquelet first reported 35 cases of large bone defect of tibia non union treated by the induced membrane technic which allow to fill bone defect with cancellous bone alone. The cement spacer allows to induce a foreign body membrane which constitute a biological chamber. Works on animal model reported by Pellissier and Viatteau showed the properties of the membrane: secretion of growths factors (VEGF, TGFbéta1, BMP2) and osteoinductive activitie of the cells. The induced membrane seem to play the role of a neo periosteum. Using this technic is possible in emergency or in septic condition where bone defect can not been solved by shortening. This technic avoids to use microsurgical technic and the limit is the quantity of avalaible cancellous bone

Study of failed Oxford medial unicompartmental knee replacements at the Royal Cornwall Hospital. Objective. we set up a retrospective study to identify the various reasons for failure of oxford medial unicompartmental knee replacements and to assess their outcome following revision. Materials and Method. Over 5 years (2006- 2010) we identified 26 failed unicompartmental knee replacements, which were revised at the Royal Cornwall hospital. We retrospectively analysed the data to include pre-operative and post-operative Oxford score, range of movement, patient satisfaction and the type of implant used. Results. There were 9 males and 17 females in our series with an average age of 65 years (49 to 80). The average follow up was 2.6 years (1 - 4.6 years). The pre-revision Oxford score was 21.3 (12 to 35), which improved to 41.7 (18 to 47) following surgery. Almost all patients benefited with increase in the range of movement. The implants were revised at an average duration of 4 years and 8 months (1 to 17 yrs) following the index operation. The commonest cause of failure was progression of arthritis in the lateral compartment 50 % (13/26), revision for unexplained pain 23 % (6/26) and aseptic loosening 23 % (6/26). There was one case of sepsis 4 % (1/26). We did not come across dislocation of the bearing. The implants were revised using primary or complex primary knee systems. The infected knee was revised using a two-stage technique. Conclusion. Unicompartmental knee replacement is a successful procedure for treating isolated medial compartment arthritis. Commonest indication for revision in our study was progression of arthritis in the lateral compartment. Revision is relatively easy and results of revision are good with high patient satisfaction. Our results are comparable to published data from larger centres

We performed 83 consecutive cemented revision total hip arthroplasties in 77 patients between 1977 and 1983 using improved cementing techniques. One patient (two hips) was lost to follow-up. The remaining 76 patients (81 hips) had an average age at revision of 63.7 years (23 to 89). At the final follow-up 18 hips (22%) had had a reoperation, two (2.5%) for sepsis, three (4%) for dislocation and 13 (16%) for aseptic loosening. The incidence of rerevision for aseptic femoral loosening was 5.4% and for aseptic acetabular loosening 16%. These results confirm that cemented femoral revision is a durable option in revision hip surgery when improved cementing techniques are used, but that cemented acetabular revision is unsatisfactory

Objectives

The surface of pure titanium (Ti) shows decreased histocompatibility over time; this phenomenon is known as biological ageing. UV irradiation enables the reversal of biological ageing through photofunctionalisation, a physicochemical alteration of the titanium surface. Ti implants are sterilised by UV irradiation in dental surgery. However, orthopaedic biomaterials are usually composed of the alloy Ti6Al4V, for which the antibacterial effects of UV irradiation are unconfirmed. Here we evaluated the bactericidal and antimicrobial effects of treating Ti and Ti6Al4V with UV irradiation of a lower and briefer dose than previously reported, for applications in implant surgery.

Objectives

The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method.

Injection or aspiration of the ankle may be performed through either an anteromedial or an anterolateral approach for diagnostic or therapeutic reasons. We evaluated the success of an intra-articular puncture in relation to its site in 76 ankles from 38 cadavers. Two orthopaedic surgical trainees each injected methylene blue dye into 18 of 38 ankles through an anterolateral approach and into 20 of 38 through an anteromedial. An arthrotomy was then performed to confirm the placement of the dye within the joint.

Of the anteromedial injections 31 of 40 (77.5%, 95% confidence interval (CI) 64.6 to 90.4) were successful as were 31 of 36 (86.1%, 95% CI 74.8 to 97.4) anterolateral injections. In total 62 of 76 (81.6%, 95% CI 72.9 to 90.3) of the injections were intra-articular with a trend towards greater accuracy with the anterolateral approach, but this difference was not statistically significant (p = 0.25). In the case of trainee A, 16 of 20 anteromedial injections and 14 of 18 anterolateral punctures were intra-articular. Trainee B made successful intra-articular punctures in 15 of 20 anteromedial and 17 of 18 anterolateral approaches. There was no significant difference between them (p = 0.5 and p = 0.16 for the anteromedial and anterolateral approaches, respectively). These results were similar to those of other reported studies. Unintended peri-articular injection can cause complications and an unsuccessful aspiration can delay diagnosis. Placement of the needle may be aided by the use of ultrasonographic scanning or fluoroscopy which may be required in certain instances.

The aim of this study was to determine the effectiveness of antibiotic-impregnated implants in the prevention of bone infection. We used a model of contaminated fracture in goats to evaluate four treatment groups: no treatment, hand-made tobramycin-impregnated polymethylmethacrylate beads, commercially-available tobramycin-impregnated calcium sulphate pellets and commercially-available tobramycin-impregnated polymethylmethacrylate beads. Three weeks after intraosseous inoculation with streptomycin-resistant Staphylococcus aureus tissue cultures showed no evidence of infection in any of the antibiotic-treated groups. All of the cultures were positive in the untreated group. These results show that effective local antibiotic delivery can be obtained with both commercially-available products and with hand-made polymethylmethacrylate beads. The calcium sulphate pellets have the advantage of being bioabsorbable, thereby obviating the need for a second procedure to remove them.

We have undertaken a prospective study in patients with a fracture of the femoral shaft requiring intramedullary nailing to test the hypothesis that the femoral canal could be a potential source of the second hit phenomenon. We determined the local femoral intramedullary and peripheral release of interleukin-6 (IL-6) after fracture and subsequent intramedullary reaming.

In all patients, the fracture caused a significant increase in the local femoral concentrations of IL-6 compared to a femoral control group. The concentration of IL-6 in the local femoral environment was significantly higher than in the patients own matched blood samples from their peripheral circulation. The magnitude of the local femoral release of IL-6 after femoral fracture was independent of the injury severity score and whether the fracture was closed or open.

In patients who underwent intramedullary reaming of the femoral canal a further significant local release of IL-6 was demonstrated, providing evidence that intramedullary reaming can cause a significant local inflammatory reaction.

The stress response to trauma is the summation of the physiological response to the injury (the ‘first hit’) and by the response to any on-going physiological disturbance or subsequent trauma surgery (the ‘second hit’).

Our animal model was developed in order to allow the study of each of these components of the stress response to major trauma. High-energy, comminuted fracture of the long bones and severe soft-tissue injuries in this model resulted in a significant tropotropic (depressor) cardiovascular response, transcardiac embolism of medullary contents and activation of the coagulation system. Subsequent stabilisation of the fractures using intramedullary nails did not significantly exacerbate any of these responses.