Aim. Periprosthetic joint infection (PJI) is a devasting complication after total hip arthroplasty. Joint aspiration and preoperative biopsy can be helpful diagnostics for PJI. The aim of this study is to evaluate the diagnostic value of preoperative biopsies after inconclusive or dry tap aspiration of the hip in patients undergoing revision hip arthroplasty. Secondarily we will evaluate the diagnostic value of synovial fluid aspiration cultures and peroperative tissue cultures for diagnosing or ruling out PJI. Methods. Patients who underwent diagnostic aspiration and subsequent preoperative biopsy and/or revision surgery between January 2015 and January 2024 were included in the study. Synovial fluid aspirations and tissue samples obtained from biopsy and revision surgery were interpreted using the European Bone and Joint Infection Society criteria for PJI and in close consultation with the microbiologist. Results. 207 Patients were included with 231 synovial fluid aspirations. Sensitivity and specificity of synovial fluid aspiration cultures were 76% and 98%. In 62 patients tissue biopsies were performed, of which 40 after a dry tap. The tissue biopsies after a dry tap aspiration had a sensitivity of 50.0% and a specificity of 95.8%. In 21% tissue biopsies led to the confirmation of PJI in patient with a high suspicion of PJI after dry tap aspiration. In patients with an inconclusive synovial fluid aspiration result the addition of tissue biopsies led to a change in treatment in 14%. In 212 cases revision surgery was performed, intraoperative tissue cultures had a sensitivity and specificity of 83.3% and 99.3%. Conclusions. Diagnosing PJI can be troublesome, especially if synovial fluid aspiration provides a dry tap. Tissue biopsy cultures in patients with a high suspicion of PJI after dry tap aspiration is a feasible way to confirm PJI, in 21% of patients PJI could be confirmed after dry tap aspiration. Ruling out PJI by means of a biopsy after a dry tap aspiration is less successful due to its low sensitivity. Tissue biopsies after an inconclusive aspiration leads to clinically important treatment changes

Introduction. External fixators are attached to bones with percutaneous pins and wires inserted through soft tissues and bone increasing the risk of infections. Such infections compromise patient outcomes e.g., through pin loosening or loss, failure of fixator to stabilise the fracture, additional surgery, increased pain, and delayed mobilisation. These infections also impact the healthcare system for example, increased OPD visits, hospitalisations, treatments, surgeries and costs. Nurses have a responsibility in the care and management of patients with external fixators and ultimately in the prevention of pin-site infection. Yet, evidence on best practices in the prevention of pin-site infection is limited and variation in pin-site management practices is evident. Various strategies are used for the prevention of pin-site infection including the use of different types of non-medicated and medicated wound dressings. The aim of this retrospective study was to investigate the use of dry gauze or iodine tulle dressings for the prevention of pin-site infections in patients with lower limb external fixators. Methodology. A retrospective study of patients with lower limb external fixators who attended the research site between 2015–2022. Setting & Sample: The setting was the outpatient's (OPD) orthopaedic clinic in a University Teaching Hospital in Dublin, Ireland. Eligibility Criteria:. Over the age of 16, treated with an Ilizarov, Taylor Spatial frame (TSF) or Limb Reconstruction System (LRS) external fixators on lower limbs,. Pin-sites dressed with dry gauze or iodine tulle,. Those with pre-existing infected wounds close to the pin site and/or were on long term antibiotics were excluded. Follow Up Period: From time of external fixator application to first pin-site infection or removal of external fixator. Outcome Assessment: The primary outcome was pin-site infection, secondary outcomes included but were not limited to frequency of pin-site infection according to types of bone fixation, frequency of pin/wire removal and hospitalisation due to infection. Data analysis: IBM SPSS Version 25 was used for statistical analysis. Descriptive and inferential statistics were conducted as appropriate. Categorical data were analysed by counting the frequencies (number and percentages) of participants with an event as opposed to counting the number of episodes for each event. Differences between groups were analysed using Chi-square test or Fisher's exact test, where appropriate. Continuous variables were reported using mean and standard deviations and difference analysed using a two-sample independent t-test or non-parametric test (Mann-Whitney), where appropriate. Using Kaplan-Meier, survival analysis explored time to development of infection. Ethical approval: granted by local institute Research Ethics Committee on 12th March 2018. Results. During the study period, 97 lower limb external fixators were applied with 43 patients meeting the study eligibility criteria. The mean age was 38 (SD 14.1; median 37) and the majority male (n=32, 74%). At least 50% (n=25) of participants had an IIizarov fixator, with 56% (n=24) of all fixators applied to the tibia and fibula. Pin/wire sites were dressed using iodine (n=26, 61%) or dry gauze dressings (n=15, 35%). The mean age of participants in the iodine group was significantly higher than the dry gauze group (p=.012). The only significant difference between the iodine and dry gauze dressing groups at baseline was age. A total of 30 (70%) participants developed a pin-site infection with 26% (n=11) classified as grade 2 infection. Clinical presentation included redness (n=18, 42%), discharge (n=16, 37%) and pain (n=15, 35%). Over half of participants were prescribed oral antibiotics (n=28, 65%); one required intravenous antibiotics and hospitalization due to pin-site infection. Ten (23%) participants required removal of pin/wires; two due to pin-site infection. There was no association between baseline data and pin-site infection. The median time to developing an infection was 7 weeks (95%, CI 2.7 to 11.29). Overall, there were 21 (81%, n=26) pin-site infections in the iodine group and nine (60%, n=15) in the dry gauze group, difference in proportion and relative risk between the dressing groups were not statistically significant (RR 1.35, 95% CI 0.86–2.12; p= .272). There was no association between baseline data, pin-site infection, and type of dressing. Conclusions. At the research site, patients are referred to the OPD orthopaedic clinic from internal and external clinical sites e.g., from Hospital Consultants, General Practitioners and occasionally from multidisciplinary teams, throughout Ireland. Our retrospective observation study found that 97 lower limb external fixators were applied over a seven-year period which is lower than that reported in the literature. However, the study period included the COVID pandemic years (2020 and 2021) which saw a lower number of external fixators applied due to lack of theatre availability, cancelled admissions and social/travel restrictions that resulted in fewer accidents and lower limb trauma cases requiring external fixator application. The study highlighted a high infection rate with 70% of participants developing pin-site infection which is in keeping with findings reporting in other studies. Our study showed that neither an iodine nor dry gauze dressing was successful in preventing pin-site infection. In the iodine group 81% of participants developed infection compared to 60% in the dry gauze group. Given the lack of difference between the two groups consideration needs to be given to the continued use of iodine dressings in the prevention of pin-site infection. Pin-site infections result in a high portion of participants being prescribed antibiotics and, in an era, that stresses the importance of antimicrobial stewardship there is a need to implement effective infection prevention and control strategies that minimise infection. Further research is therefore needed to investigate more innovative medicated dressings such as those that contain anti-microbial or anti-bacterial agents

The purpose of this study was to validate a dry model for the assessment of performance of arthroscopic rotator cuff repair (RCR) and labral repair (LR). We hypothesised that the combination of a checklist and a previously validated global rating scale (GRS) would be a valid and reliable means of assessing RCR and LR when performed by residents in a dry model. An arthroscopic RCR and LR was performed on a dry model by residents, fellows, and sports medicine staff. Any prior RCR and LR exposure was noted. Participants were given a detailed surgical manuscript and technique video before the study began. Evaluation of residents was performed by staff surgeons with task-specific checklists created using a modified Delphi procedure, and the Arthroscopic Surgical Skill Evaluation Tool (ASSET). The hand movements and arthroscopic view of the procedures were recorded. Both videos were scored by a fellow blinded to the year of training of each participant. A total of 35 residents, six fellows and five staff surgeons performed both arthroscopic RCR and LR on a dry model model (48 total). The internal reliability (Cronbach's Alpha) of the test using the total ASSET score was high (>0.8)). One-way analysis of variance for the total ASSET score and the total checklist score demonstrated a difference between participants based upon year of training (p<0.05). Post hoc analysis also demonstrated a significant difference in global ratings and checklist scores between junior residents (PGY1–3) and senior residents (PGY4&5), senior residents and fellows, and fellows and staff. A good correlation was seen between the total ASSET score and prior exposure to RCR and LR. The inter-rater reliability (ICC) between the examiner ratings and the blinded assessor ratings for the total ASSET score was good (0.8). The results of this study provide evidence that the performance of a RCR and LR in a dry model is a valid and reliable method of assessing a resident's ability to perform these procedures, prior to performance in the operating room

Introduction. Demineralised Bone Matrix (DBM) is widely used in Orthopaedics and dentistry as a bone graft substitute and may be used to augment bone formation in load bearing applications. In this study we examine the effect of gamma irradiation and freeze drying on the tensile strength of Demineralised Cortical Bone (DCB). Methods. Tibias were harvested from mature ewes and cut into bony strips. Demineralisation was done using 0.6M HCL and confirmed by X-ray. Specimens were washed until a pH of 7.0 +/_ 0.2 was achieved in the washing solutions. Specimens were allocated into 4 groups; group (A) non freeze dried non gamma irradiated, group (B) freeze dried non gamma irradiated, group (C) non freeze dried gamma irradiated mention the level of gamma irradiation and group (D) freeze dried and gamma irradiated. The maximum tensile force and stress were measured. Statistical analysis using the Mann-Whitney U test was carried out. Results. The Median of maximum tensile force for group (A) was 218N, group (B) was 306N, group (C) was 263N and for group (D) was 676N. Group (D) results were statistically higher (p=< 0.05) compared to group (A) and (C), while there was no statistical significance compared to group (B). Conclusion. Previously published studies suggested the possibility of using DCB as ACL graft substitute. We examined the effect of gamma radiation as the most common sterilisation technique in medical field and the freeze drying as a possible technique for long term storage on the tensile strength of the DCB. Freeze drying significantly increases the tensile strength of the DCB while gamma irradiation has no significant effect. Our results indicate that freeze dried gamma irradiated DCB can be used as a ligament substitute

Introduction. Chronic Achilles tendinopathy is a common overuse injury. There are several modalities of treatment, reflecting difficulties in its management. In particular, due to the well-recognised morbidity associated with surgical decompression, treatment has steered towards a less invasive route. Dry needling has been efficacious in managing other tendinopathies. This study therefore assessed dry needling and percutaneous hydrostatic decompression of the Achilles tendon as a novel treatment for this condition. Methods. Twenty-two patients with 27 sonographically-confirmed chronic Achilles tendinopathy were prospectively enrolled. All were symptomatic for >6 months and have failed alternative conservative treatments. Ultrasound-guided dry needling of neovascular areas and paratenon hydrostatic decompression was performed by a dedicated musculoskeletal radiologist on a 6-weekly basis until symptomatic resolution or no improvement was evident. Sonographic assessment of the tendon's thickness and neovascularity was undertaken. Following treatment, a standardized physiotherapy regime was adopted. At baseline and 6 weeks post-final procedure, visual analogue scores (VAS) at rest and during activity were obtained. Telephonic interviews were carried out 12 and 24 months post-treatment. Results. 24 tendons (in 19 patients) were successfully treated - 1 patient had spontaneous symptomatic resolution and 2 progressed to surgical intervention. The mean number of treatment sessions was 2. There was no significant change in neovascularity or tendon thickness after treatment. Therapeutic intervention led to a significant improvement in VAS at rest (42 v 18.4, p=0.0005) and during activity (74 v 33.7, p< 0.0001). At 12 months, 77% of patients were >80% satisfied with their outcome of the procedure, with 85% of patients able to return to their sporting interests. At 24 months, 90% of patients were >80% satisfied with their outcome, with nearly half having complete symptomatic resolution. Conclusion. Dry needling and percutaneous paratenon decompression under ultrasound guidance shows promise as an alternative treatment for this chronic condition

Introduction. Pre-operative aspiration and culture is the gold standard for the diagnosis of peri-prosthetic infection. This study aimed to ascertain the diagnostic accuracy of culture of joint aspiration with or without saline re-aspiration in the event of a dry-tap. Patients/Materials & Methods. Retrospective analysis of 343 hip aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre-operative aspiration is routine. Results. Fluid was aspirated in 141(41%) cases and dry taps in which saline injection-re-aspiration was performed occurred in 202 (59%) cases. Overall sensitivity and specificity of diagnostic aspirate were 82% (74–88%) and 79% (74–84%) respectively. Sensitivity and specificity of saline injection-re-aspiration after dry tap were 79% (64–87%) and 86% (78–92%) compared to 84% (74–91%) and 74% (66–81%) for direct aspiration. Discussion. Pre-operative joint aspiration and culture is a sensitive and specific test for the confirmation of diagnosis in patients at a moderate to high risk of prosthetic joint infection. Culture of saline injection-re-aspiration also provides accurate diagnostic information in the event of a dry tap. Both methods allow susceptibility testing of relevant organisms and are therefore able to guide peri-operative and cement instilled antibiotic therapy. Conclusions. Culture of pre-operative joint aspirates provides sensitive and specific diagnostic information, including antimicrobial susceptibility results. Saline injection-re-aspiration is a useful additional technique in those patients in whom fluid cannot be aspirated

No single test is 100% sensitive and specific for the diagnosis of prosthetic joint infection. Joint aspiration is currently the only preoperative investigation that can establish the identity of the infecting organism and its antibiotic susceptibilities. Frequently when attempting to aspirate a joint a ‘dry tap occurs as fluid cannot be aspirated. In this situation, normal saline may be injected into the joint and then reaspirated to provide fluid for culture. The aim of this study was to ascertain the diagnostic accuracy of culture of joint aspiratie with or without saline reaspiration in the event of a dry tap. A retrospective analysis of 580 hip and knee aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre operative aspiration is routine. Fluid was aspirated in 313 (54%) cases and dry taps in which saline injection reaspiration was performed occurred in 267 (46%) cases. Overall sensitivity and specificity of diagnostic aspiration were 84% (78–89%) and 85% (81–88%) respectively. Sensitivity and specificity of saline injection-reaspiration after dry tap were 87% (79–82%) and 79% (72–84%) compared to 81% (71–88%) and 90% (85–93%) for direct aspiration. Pre operative joint aspiration and culture is a sensitive and specific test for the confirmation of diagnosis in patients at a moderate to high risk of prosthetic joint infection. Culture of saline injection-reaspiration also provides accurate diagnostic information in the event of a dry tap. Both methods allow susceptibility testing of relevant organisms and are therefore able to guide peri-operative and cement instilled antibiotic therapy. Culture of pre operative joint aspirates provides sensitive and specific diagnostic information including antimicrobial susceptibility results. Saline injection-reaspiration is a useful additional technique in those patients in whom fluid cannot be aspirated

Objectives. During open orthopaedic surgery, joints may be exposed to air, potentially leading to cartilage drying and chondrocyte death, however, the long-term effects of joint drying in vivo are poorly understood. We used an animal model to investigate the subsequent effects of joint drying on cartilage and chondrocytes. Methods. The patellar groove of anaesthetised rats was exposed (sham-operated), or exposed and then subjected to laminar airflow (0.25m/s; 60 minutes) before wounds were sutured and animals recovered. Animals were monitored for up to eight weeks and then sacrificed. Cartilage and chondrocyte properties were studied by histology and confocal microscopy, respectively. Results. Joint drying caused extensive chondrocyte death within the superficial regions of cartilage. Histology of dried cartilage demonstrated a loss of surface integrity at four weeks, fibrillations at eight weeks, and an increased modified Mankin score (p < 0.001). Cartilage thickness increased (p < 0.001), whereas chondrocyte density decreased at four weeks (p < 0.001), but then increased towards sham-operated levels (p < 0.01) at eight weeks. By week eight, chondrocyte pairing/clustering and cell volume increased (p < 0.05; p < 0.001, respectively). Conclusions. These in vivo results demonstrated for the first time that as a result of laminar airflow, cartilage degeneration occurred which has characteristics similar to those seen in early osteoarthritis. Maintenance of adequate cartilage hydration during open orthopaedic surgery is therefore of paramount importance. Cite this article: Dr A. Hall. Drying of open animal joints in vivo subsequently causes cartilage degeneration. Bone Joint Res 2016;5:137–144. DOI: 10.1302/2046-3758.54.2000594

Background. Plantar fasciitis is a frequently chronic and disabling cause of foot pain in adults. This prospective study aims to evaluate the analgesic effect of ultrasound guided dry needling in patients with chronic plantar fasciitis, refractory to conservative treatment. Method and Materials. Patients undergoing dry needling for plantar fasciitis, followed by perifascial injection between Jan ′09 and Feb ′10 were identified. Pain scores were recorded on a visual analogue scale from 0 (no pain) to 10 (worst pain possible) before the procedure, 2 weeks and 6 weeks post procedure. Patients were also contacted in April to assess their current pain level. Responses were graded as excellent (> 75% pain score improvement), good (50-74%), fair (25-49%) and poor (<25% relief). Any complications or need for any further intervention were recorded. Results. 55 feet (46 patients) were identified. All patients had had no relief with previous treatment. 24 feet who had calf tightness had undergone a gastrocnemius muscle lengthening. All patients had radiological confirmation of diagnosis prior to undergoing the procedure. At 2 weeks: 1 foot lost to follow-up. 43/54 feet had excellent or good pain relief. At 6 weeks: 5 feet (4 patients) were lost to follow up. 37 feet (28 patients) reported excellent or good pain relief. 11/13 feet patients with fair to poor response underwent a repeat procedure. Redo-Procedure. Using the same outcome measures, 8/11 and 9/11 feet had excellent or good response at 2 and 6 weeks respectively. Long-term follow-up:. 42 feet (34 patients) were contacted. 13 feet (12 patients) lost to follow-up. Follow-up duration from 2 to 13 months. Mean F/U = 7 months. 23 feet (5 redos) had excellent or good outcome 19 feet (6 redos) had fair or poor outcome. If symptoms reoccurred, average duration of total analgesic effect was 3 months. Conclusion. 80% and 74% of patients had excellent or good outcome at 2 and 6 weeks respectively. After an average of 7 months follow-up, 55% patients had excellent or good results. In those patients in whom symptoms recurred, the average duration of total analgesic effect was 3 months. We believe that ultrasound guided dry needling is an effective treatment method for plantar fasciitis

Aims. Tissue adhesives (TAs) are a commonly used adjunct to traditional surgical wound closures. However, TAs must be allowed to dry before application of a surgical dressing, increasing operating time and reducing intraoperative efficiency. The goal of this study is to identify a practical method for decreasing the curing time for TAs. Methods. Six techniques were tested to determine which one resulted in the quickest drying time for 2-octyle cyanoacrylate (Dermabond) skin adhesive. These were nothing (control), fanning with a hand (Fanning), covering with a hand (Covering), bringing operating room lights close (OR Lights), ultraviolet lights (UV Light), or prewarming the TA applicator in a hot water bath (Hot Water Bath). Equal amounts of TA were applied to a reproducible plexiglass surface and allowed to dry while undergoing one of the six techniques. The time to complete dryness was recorded for ten specimens for each of the six techniques. Results. Use of the Covering, OR Lights, and Hot Water Bath techniques were associated with a 25- (p = 0.042), 27- (p = 0.023), and 30-second (p = 0.009) reduction in drying time, respectively, when compared to controls. The UV Light (p = 0.404) and Fanning (p = 1.000) methods had no effect on drying time. Conclusion. Use of the Covering, OR Lights, and Hot Water Bath techniques present a means for reducing overall operating time for surgeons using TA for closure augmentation, which can increase intraoperative efficiency. Further studies are needed to validate this in vivo. Cite this article: Bone Jt Open 2022;3(8):607–610

Retained polymethylmethacrylate (PMMA) debris in surgical instrument trays is a rare, but disquieting situation for the arthroplasty surgeon. Although retained debris could be considered to be sterile after autoclaving, there is no peer-reviewed literature to support this assumption. This uncertainty and subsequent fear of contamination from this bioburden often leads to operating room personnel turning over entire surgical tables and opening new surgical instruments, which consumes time and burdens a hospital's sterilization infrastructure. Consequently, the purpose of the current study was to determine if retained, heavily contaminated PMMA in surgical trays could be effectively sterilized through clinically utilized autoclave protocols. MSSA (Xen36, Perkin Elmer) biofilm was grown on identically sized PMMA (Palacos R) coupons for 72-hour duration. Following incubation, coupons were exposed to three commonly used sterilization protocols. Cobalt-Chrome (CC) coupons were included in the same tray, replicating instruments in proximity to retained PMMA. Autoclave protocols included: 1.) Single Instrument Flash protocol: Pre-vac, 270° F, 10 min exposure, 1 min drying, 2.) One Tray OR protocol: Pre-vac, 270° F, 4 min exposure, 1 min drying, and 3.) Standard Post-Operative protocol: Pre-vac, 270° F, 10 min exposure, 60 min drying. Control coupons did not undergo autoclaving. Coupons were then sonicated for 30 minutes in tryptic soy broth and plated to count CFUs. Experiments were performed in quadruplicate. Control coupons showed significant contamination with CFU counts in the range of 10. 6. CFU/mL. CFU counts of zero across all autoclaved PMMA and CC coupons revealed that each protocol was effective in completely eradicating culturable S. aureus, confirming clinical efficacy on orthopaedic cement sterilized in surgical trays. Our findings demonstrate that heavily contaminated PMMA and exposed metal in surgical trays can be effectively sterilized through several autoclaving protocols. Clinicians should feel confident in the efficacy of autoclave protocols in removing bacteria and its associated biofilm from othopaedic materials

Design of bone tissue engineering scaffolds imposes a number of requirements for their physical properties, in particular porosity and mechanical behaviour. Alginates are known as a potential material for such purposes, usually deploying calcium as a cross-linker. Calcium over-expression was reported having proinflammatory effect, which is not always desirable. Contrary to this, barium has better immunomodulatory outcome but data for barium as a cross-linker are scarce. In this work the objective was to produce Ba-linked alginates and compare their viscoelastic properties with Ca-linked controls in vitro. Sodium alginate aqueous solution (1 wt%) with 0.03 wt.% CaCl. 2. is gelled in dialysis tubing immersed in 27 mM CaCl. 2. (controls) or BaCl. 2. , for 48 h, followed by freeze-drying and rehydration (with 0.3 wt.% CaCl. 2. and 0.8 wt.% NaCl). Hydrogel discs (diameter 8-10 mm, thickness 4-6 mm) were assessed in dry and wet (DMEM immersed) states by dynamic mechanical analysis (DMA) under compressive creep conditions with increased loads, frequency scans and strain-controlled sweeps in physiological range (0.1-20 Hz) at 25°C and 37°C. Resulting data were analysed by conventional methods and by a model-free BEST (Biomaterials Enhanced Simulation Testing) to extract invariant values and material functions. Significant differences were observed in properties of Ba-linked hydrogel scaffolds vs. Ca-linked controls. Specifically, for the similar porosity Ba-samples exhibited lower creep compliance, higher dynamical stiffness and lower loss factor in the whole studied range. Invariant modulus exhibited a non-linear decay vs. applied stress. These differences were observed in both dry and wet states and temperatures. Use of barium as a cross-linker for alginates allows further modification of biomechanical properties of the scaffolds for better compliancy to the tissues in the application. Barium release might have an immunomodulating effect but also promote ion exchange for osteogenesis due to additional Ca/Ba concentration gradient

Introduction. Histology is still considered the gold standard method for the evaluation of soft tissues in the musculoskeletal field, thanks to the possibility of studying structures using different staining and high magnification microscopy. To overcome the intrinsic limits of this method, contrast enhanced microtomographic (CE- microCT) protocols are constantly evolving to allow 3D study of soft tissues. However, no standardized approaches are available, and many concerns exist about the alterations induced to the samples. Method. microCT/histology protocols were explored on human tendons and menisci. To enhance contrast tissues for microCT scanning 1) examethyldisilazane drying 2) 2% phosphotungstic acid (PTA) in alcoholic solution exposition and 3) 2% PTA in aqueous solution exposition were performed; to observe PTA contrast progression, three exposition and scanning times were selected. microCT images were compared to histological slices obtained from the same samples, after rehydration protocols, or from adjacent tissues portion, stained with Picrosirius red to highlight the peculiar collagenic structures. Result. Exposition times influence PTA diffusion and tissue contrast; its specificity for collagenic structure allow a clearer contrast of the tissues. Histological processing on the same samples is possible: PTA removal requires careful washing in basic solution to reduce the hardening of the sample, while drying can be reverted applying inverse protocol. Comparison with microCT images is really accurate if histology is performed on the same sample, although all protocols induce tissue shrinkage with relative packing of collagen fibers. Conclusion. The contrast approaches tested proved effective in highlighting the structures of both tendons and menisci, but the structural effects induced by tissue shrinkage do not allow a completely real microCT visualization of native tissue. Histology can be the reference method to monitor the efficacy of the contrast methods and the alterations induced to define the possibility of improvement of the technique. Acknowledgement. PR23-PAS-P4 “ADJOINT 2”- INAIL

Abstract. Objective. In this systematic review we aim to compare wound complication rates from Negative Pressure Wound Therapy (NPWT) to dry sterile surgical dressings in primary and revision total knee arthroplasty (TKA). Methods. A search was performed using PubMed, Embase, Science Direct, and Cochrane Library. Eligible studies included those investigating the use of NPWT in primary and revision TKA. Exclusion criteria included studies investigating NPWT not related to primary or revision TKA; studies in which data relating to NPWT was not accessible; missing data; without an available full text, or not well reported. We also excluded studies with poor scientific methodology. All publications were limited to the English language. Abstracts, case reports, conference presentations, and reviews were excluded. Welch independent sample t-test was used for the statistical analysis. Results. Our review identified 11 studies evaluating 1,414 patients. Of the 1,181 primary TKA patients analysed (NPWT = 416, surgical dressing = 765), the overall wound complication rates in patients receiving NPWT ranged from 0% – 63% (Median 7.30%, SD ± 21.44) This is in comparison to complication rates of 2.8% – 19% (Median 6.50%, SD ± 6.59) in the dry dressing group. The difference in complication rates between the two groups was not statistically significant (p =0.337). In the revision TKA cohort of 279 patients (NPWT group = 128, dry dressing group = 151), the overall wound complication rates in the NPWT group ranged between 6.7% – 12% (Median 9.80%, SD ± 2.32) vs 23.8% – 30% (Median 26.95%, SD ± 2.53) in the dry dressing group. This difference was statistically significant (p<0.001). Conclusion. NPWT dressing demonstrated statistically significant reduction in wound complication rates when used in revision TKA but not primary TKA when compared to dry sterile dressings. This is probably due to higher wound related risks encountered with revision TKA surgery compared to primary TKA surgery. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Aim. Local antibiotics released through a carrier is a commonly used technique to prevent infection in orthopaedic procedures. An interesting carrier in aseptic bone reconstructive surgery are bone chips impregnated with AB solution. Systemically administered Cefazolin (CFZ) is used for surgical site infection prophylaxis however in vitro study showed that fresh frozen and processed bone chips impregnated with CFZ solution completely release the CFZ within a few hours. On the other hand irradiated freeze-dried bone chips, treated with supercritical CO2 (scCO2) have been shown to be an efficient carrier for the antibiotics vancomycine or tobramycine. With this pilot study we wanted to investigate if CFZ solution impregnation of bone chips treated with scCO2 shows a more favorable release pattern of CFZ. Method. The bone chips were prepared using the standard scCO2 protocol and were impregnated with 100 mg/ml cefazolin at different timepoints during the process: before freeze drying (BC type A), after freeze drying (BC type B) and after gamma-irradiation. 0.5g of the impregnated bone grafts were incubated with 5ml of fetal calf serum (FCS) at 37°C. At 2, 4, 6, 8 and 24h of incubation 200µl of eluate was taken for analysis. After 24h the remaining FCS was removed, bone grafts were washed and new FCS (5ml) was added. Consecutive eluate samples were taken at 48, 72 and 96h of incubation. The concentration of CFZ in the eluates was measured with the validated UPLC-DAD method. Analysis was performed in triplicate. Results. The mean concentration of CFZ in the eluate obtained from BC type A incubated for 2h was higher compared to BC type B, respectively 581 mg/l and 297 mg/l. However, the elution profile is the same for both types: the CFZ concentration in the eluates drops within the first 24h from 581 mg/l to 365 mg/l (37%) for BC type A and from 297 mg/l to 132 mg/l (56%) for BC type B. After 24h no further significant CFZ release is seen. Impregnation of the bone chips before or after gamma irradiation did not affect this elution profile. Conclusions. Bone chips treated with scCO2 show a comparable elution pattern compared to non-scCO2 treated bone chips. AB release depends on the properties of the AB, making it impossible to copy the same impregnation protocol for different antibiotics. The stability of CFZ in solution at 37°C and its release are a major concern when establishing an impregnation protocol with CFZ

The aim of this study is to print 3D polycaprolactone (PCL) scaffolds at high and low temperature (HT/LT) combined with salt leaching to induced porosity/larger pore size and improve material degradation without compromising cellular activity of printed scaffolds. PCL solutions with sodium chloride (NaCl) particles either directly printed in LT or were casted, dried, and printed in HT followed by washing in deionized water (DI) to leach out the salt. Micro-Computed tomography (Micro-CT) and scanning electron microscope (SEM) were performed for morphological analysis. The effect of the porosity on the mechanical properties and degradation was evaluated by a tensile test and etching with NaOH, respectively. To evaluate cellular responses, human bone marrow-derived mesenchymal stem/stromal cells (hBMSCs) were cultured on the scaffolds and their viability, attachment, morphology, proliferation, and osteogenic differentiation were assessed. Micro-CT and SEM analysis showed that porosity induced by the salt leaching increased with increasing the salt content in HT, however no change was observed in LT. Structure thickness reduced with elevating NaCl content. Mass loss of scaffolds dramatically increased with elevated porosity in HT. Dog bone-shaped specimens with induced porosity exhibited higher ductility and toughness but less strength and stiffness under the tension in HT whereas they showed decrease in all mechanical properties in LT. All scaffolds showed excellent cytocompatibility. Cells were able to attach on the surface of the scaffolds and grow up to 14 days. Microscopy images of the seeded scaffolds showed substantial increase in the formation of extracellular matrix (ECM) network and elongation of the cells. The study demonstrated the ability of combining 3D printing and particulate leaching together to fabricate porous PCL scaffolds. The scaffolds were successfully printed with various salt content without negatively affecting cell responses. Printing porous thermoplastic polymer could be of great importance for temporary biocompatible implants in bone tissue engineering applications

The purpose of this study is to enhance massive bone allografts osseointegration used to reconstruct large bone defects. These allografts show >50% complication rate requiring surgical revision in 20% cases. A new protocol for total bone decellularisation exploiting the vasculature can offer a reduction of postoperative complication by annihilating immune response and improving cellular colonization/ osseointegration. The nutrient artery of 18 porcine bones - humerus/femur/radius/ulna - was cannulated. The decellularization process involved immersion and sequential perfusion with specific solvents over a course of one week. Perfusion was realized by a peristaltic pump (mean flow rate: 6ml/min). The benefit of arterial perfusion was compared to a control group kept in immersion baths without perfusion. Bone samples were processed for histology (HE, Masson's trichrome and DAPI for cell detection), immunohistochemistry (IHC : Collagen IV/elastin for intraosseous vascular system evaluation, Swine Leukocyte Antigen – SLA for immunogenicity in addition to cellular clearance) and DNA quantification. Sterility and solvent residues in the graft were also evaluated with thioglycolate test and pH test respectively. Compared to native bones, no cells could be detected and residual DNA was <50ng/mg dry weight. Intramedullary spaces were completely cleaned. IHC showed the preservation of intracortical vasculature with channels bounded by Collagen IV and elastin within Haversian systems. IHC also showed a significant decrease in SLA signaling. All grafts were sterile at the last decellularization step and showed no solvent residue. The control group kept in immersion baths, paired with 6 perfused radii/ulnae, showed that the perfusion is mandatory to ensure complete decellularisation. Our results prove the effectiveness of a new concept of total bone decellularisation by perfusion. These promising results could lead to a new technique of Vascularized Composite Allograft transposable to pre-clinical and clinical models

This study aimed to describe the morphology of the coracoid process and determine the frequency of commonly observed patterns. The second purpose was to determine the location of inferior tunnel exit with superior based tunnel drilling and the superior tunnel exit with inferior based tunnel drilling. A sample of 100 dry scapulae for the morphology aspect and 52 cadaveric embalmed shoulders for tunnel drilling were used. The coracoid process was described qualitatively and categorized into 6 different shapes. A transcoracoid tunnel was drilled at the centre of the base. Twenty-six shoulders were used for the superior-inferior tunnel drilling approach and 26 for the inferior-superior tunnel drilling approach. The distances to the margins of the coracoid process, from both the entry and exit points of the tunnel, were measured. Eight coracoid processes were of convex shape, 31 of hooked shape, 18 of irregular shape, 18 of narrow shape, 25 of straight shape, and 13 of wide shape. The mean difference for the distances between superior entry and inferior exit from the apex was Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation 3.65+3.51mm (p=0.002); 1.57+2.27mm for the lateral border (p=0.40) and 5.53+3.45mm for the medial border (p=0.001). The mean difference for the distances between inferior entry and superior exit from the apex was 16.95+3.11mm (p=0.0001); 6.51+3.2mm for the lateral border (p=0.40) and 1.03+2.32 mm for the medial border (p=0.045). The most common coracoid process shape observed was a hooked pattern. Both superior to inferior and inferior to superior tunnel drilling directed the tunnel from a more anterior and medial entry to a posterior-lateral exit. Superior to inferior drilling resulted in a more posteriorly angled tunnel. With inferior to superior tunnel drilling cortical breaks were observed at the inferior and medial margin of the tunnel

Introduction. In tissue engineering, the establishment of sufficient vascularization is essential for tissue viability and functionality. Inadequate vascularization disrupts nutrients and oxygen supply. Nonetheless, regenerating intricate vascular networks represents a significant challenge. Consequently, research efforts devoted to preserving and regenerating functional vascular networks in engineered tissues are of paramount importance. The present work aims to validate a decellularisation process with preservation of the vascular network and extracellular matrix (ECM) components in fasciocutaneous flaps. Method. Five vascularized fasciocutaneous flaps from cadaveric donors were carefully harvested from the anterolateral thigh (ALT), preserving the main perforator of the fascia lata. The entire ALT flap underwent decellularization by perfusion using a clinically validated chemical protocol. Fluoroscopy and computed tomography (CT) were used to analyze the persistence of the vascular network within the flap, pre- and post-decellularization. Histological analysis, including hematoxylin and eosin staining, and quantitative DNA assessment evaluated decellularization efficacy. Further qualitative (immunohistochemistry, IHC) and quantitative analyses were conducted to assess the preservation of ECM components, such as collagen, glycosaminoglycans, and elastin. Result. On average, the ALT flap maintains 82% of the perfusion area (p = 0.094) post-treatment. Histological analysis confirmed decellularization efficacy and revealed structural rearrangement. Paired analysis revealed a significant decrease in DNA levels (<14.8 ng/mg of dry weight, p****< 0.0001) and well-maintained ECM. IHC indicated the persistence of elastine, collagen IV and laminin. Quantitative analysis confirmed elastin (p = 0.44) and collagen persistence (+74%, p*** = 0.001, albeit with a decrease in matrix glycosaminoglycans (-41%, p*** = 0.01). Conclusion. Decellularization effectively removed cells, while preserving the ECM overall and maintaining some vascular network integrity. Yet, further study is needed to validate these findings, involving microCT examination of the vascular network and its ability to support cell colonization and viability

Osteosarcoma and other types of bone cancers often require bone resection, and backfill with cement. A novel silorane-based cement without PMMA's drawbacks, previously developed for dental applications, has been reformulated for orthopedic use. The aim of this study is to assess each cement's ability to elute doxorubicin, maintain its potency, and maintain suitable weight-bearing strength. The silorane-based epoxy cement was synthesized using a platinum-based Lamoreaux's catalyst. Four groups of cement were prepared. Two PMMA groups, one without any additives, one with 200 mg of doxorubicin. Two silorane groups: one without any additive, one with doxorubicin, added so that the w% of drug into both cements were equal. Pellets 6 × 12 mm were used for testing (ASTM F451). n=10. Ten pellets from each group were kept dry. All others were placed into tubes containing 2.5 mL of PBS and stored at 37 °C. Elution from doxorubicin-containing groups were collected every day for 7 days, with daily PBS changeout. Antibiotic concentrations were determined via HPLC. Compressive strength and compressive modulus of all groups were determined for unsoaked specimens, and those soaked for 7 and 14 days. MTT assays were done using an MG63 osteosarcoma cell line. Both cements were able to elute doxorubicin over 7 days in clinically-favorable quantities. For PMMA samples, the incorporation of doxorubicin was shown to significantly affect the compressive strength and modulus of the samples (p<0.01). Incorporation of doxorubicin into silorane had no significant effect on either (p>.05). MTT assays indicated that doxorubicin incorporated into the silorane cement maintained its effectiveness whereas that into PMMA did not. At the dosing used, both cements remained above the 70 MPa. Both PMMA and silorane-based cements can deliver doxorubicin. Doxorubicin, however, interacts chemically with PMMA, inhibiting polymerization and lowering the chemotherapeutic's effectiveness