INTRODUCTION. We have conducted interface bioactive bone cement method (IBBC) in total hip arthoplasty (THA) to prevent generation of connective tissue and osteolysis for the longevity of cemented THA since 1985, in which non-resorbable crystalline osteoconductive hydroxyapatite (HA) granules were interposed on the interface between bone and bone cement. To prevent the patients from infection, we use HA granules impregnated with antibiotics. However, there have been no reports on the loading and release of antibiotics from fine granules of HA. Here, we have investigated the loading of antibiotics on HA and their release in vitro. MATERIALS AND METHODS. HA was impregnated with antibiotics such as flomoxef sodium (F), vancomycin hydrochloride (V) cefotiam dihydrochloride (C) and cefozopran hydrochloride (CE) under normal or reduced pressure. After washing with PBS three times, HA loaded with the antibiotic was placed in PBS. An aliquot of solution was sampled at appropriate time intervals and the amount of the released antibiotic was estimated based on the anti-bacterial activity. RESULTS AND DISCUSSION. When drug loading was done by dropping antibiotic solution to HA granules, the amount of antibiotic released from 20 mg of HA was 16 μg for F, 0 μg for V, 13 μg for C and 65 μg for CE. The release of F continued for 48 hrs and that of V and CEcompleted within 24 hrs. On the other hand, when antibiotics loading were conducted under reduced pressure, the amount of released antibiotic was 14 μg for F, 0 μg for V, 0 μg for C and 1670 μg for CE. The burst release was observed for CE and F, and the release of them completed in 24 hrs. Then, the release of C and CE was observed in 0.025 M EDTA solution after the antibiotic was loaded under pressure. Observation was done for 19 days, at which one third of HA was dissolved. After 40 μg of burst release, the release of C continued for 19 days, at which the total amount of C released was 122 μg. Meanwhile, the release of CE continued over 19 days, during which 3350μg of CE was released after the burst release of 3280 μg. Thus, CE seemed the most suitable antibiotic for our purpose. The burst release of CE absorbed in HA following the issue of CE surrounding the HA granules on the interface of bone and bone cement is very effective for the protection of early infection after joint replacement

Purpose. CentPillar GB HA stem (stryker®) is developed as the stem fitting the Japanese femur, and now there is CentPillar TMZF HA stem (stryker®) as the improvement type of the stem by coating the PureFix HA with plasma spray. We observed the factors which influenced on the stem subsidence between the two-type stems. Materials and Methods. We intended for 26 hips 23 patients that we performed total hip arthroplasty (THA) during the period between January 2005 and June 2009 and were able to follow up more than three years. 10 males 11 hips and 13 females 15 hips, the mean age at the time of surgery was 56.5 (range, 29–74) years old, and primary diseases were osteoarthritis (OA) in 17 hips, Idiopathic Osteonecrosis of Femoral Head (ION) in six hips, and rheumatoid arthritis (RA) in three hips. 16 hips were treated with the CentPillar GB HA stem (G group), and 10 hips were performed with the CentPillar TMZF HA stem (T group). The examination items are the stem size, the canal fill ratio of the stem (the top of lesser trochanter, the bottom of lesser trochanter, the distal portion of the stem) and the stem alignment (on anteroposterior radiograph and Lauenstein view). Results. The mean stem subsidence was 1.75 mm (range, 0–8.9 mm) in the G group, and 0.87 mm (range, 0–2.9 mm) in the T group. Although there was no significant difference, it accepted the tendency that the stem subsidence in the G group was larger than its in T group. The case in which the stem subsidence more than 2 mm was found at were 7 hips in the G group, whereas it was only one hip in the T group. The stem size, the canal fill ratio of the stem and the stem alignment were no meaningful effect on the stem subsidence. In F-test, the stem subsidence of the G group had significantly large dispersion compared with the T group (P<0.01). Discussion and Conclusion. Although there were no significant differences in the stem subsidence between the two groups, the variation of the stem subsidence was significantly small in the T group. We examined the factor which affected the stem subsidence, but neither item recognized meaningful relation, and the influence such as differences of the surface processing was considered. In fact, the strength of the TMZF HA stem improved for the GB HA stem with TMZF titanium alloy, the contact area with the bone spread by coating the PureFix HA with plasma spray, the elasticity of TMZF became closer to the bone, and the strong proximal fixation were enabled. In THA with the GB HA stem, variation of the stem subsidence was significantly large, so considerable attention for the excessive stem subsidence was required

Introduction:. Distal femoral replacement is recognised as the optimum treatment for malignant distal femoral tumours. Aseptic loosening is known to be a major cause for failure in these implants. Studies have indicated that the HA coated collar promotes osteointegration and bony in growth. This study compares long term aseptic loosening in implants with HA coated collars to those without in the immature skeleton. Objectives:. To assess the effect of HA coated collars on aseptic loosening in extendable distal femoral replacement prosthesis in the immature skeleton. Methods:. All paediatric patients undergoing distal femoral replacement with extendable prosthesis were retrospectively reviewed between 1980–2003. A total of 32 patients were reviewed. 24 patients underwent distal femoral replacement with extendable prostheses without a HA coated collar. This cohort was compared to 18 patients who were treated with an extendable prosthesis with a HA coated collar between 2001–03. Average follow up in patients without a collar was 10.1 yrs (6–18) and 8.1 yrs in those with a collar (4–11). All patients with identified infection were excluded. Radiographs taken at last follow-up were analysed for loosening. Results:. Thirty-one patients were treated for primary osteosarcoma and one for a histiocytoma. Average age at operation was 13 yrs for both groups (non-collared 6–17, collared 4–11). Three of 24 patients in the non-collared cohort underwent revision compared to 1 of 18 in the collared group. The cause of revision in the collared group was infection. One patient in each cohort died within 5 years of surgery. Mean loosening score at last follow up for the non-collared group was 11.2 compared to 2.5 for the collared group with a p value of <0.05 (Mann Whitney-U). Conclusions:. Aseptic loosening is a major cause of failure for distal femoral replacement prosthesis. HA coated collars have been shown to promote osteointegration. Little comparable data exists between collared and non-collared extendable prosthesis in the immature skeleton. Our data demonstrates that HA coated collars significantly reduce long term loosening in the immature skeleton

Introduction. Intra-articular (IA) injections of corticosteroids and hyaluronic acid (HA) products are used to treat patients with knee osteoarthritis pain that has not responded to more conservative treatment. Corticosteroids are a standard of care despite only suggestive clinical evidence of 12 or more weeks of pain relief. However the duration of pain relief with this treatment appears to be short and not a long term solution. Methods. A double-blinded, randomised, active controlled, multicentre non-inferiority trial with 442 subjects provided a pragmatic comparison of HA to methylprednisolone. These patients were collected prospectively and with excellent long term follow-up. Results. The HA responder rates were good at 12 weeks and better at the later time points (6 to 9 months) while the methylprednisolone rate decreased significantly by 26 weeks. Conclusion. HA appears to be a reasonable mid to long term solution for patients with Kellgren grade 1 and 2 arthritis. It lasts longer than steroids and has what appears to be a cost-effective advantage

Introduction. IBBC (interfacial bioactive bone cement method, Oonishi) (1) is an excellent technique for augmenting cement-bone fixation in the long term. However, the technique is difficult and there are concerns over some points, such as bleeding control, disturbance of cement intrusion to anchoring holes by granules, difficulty of the uniform granular dispersion to the acetabular bone (Zone 1 in particular). To improve this technique, we have modified IBBC (M-IBBC), and investigated the short-term clinical results and radiographic changes. Materials and Methods. K-MAX HS-3 THA (Kyocera Medical, Japan), with cemented stem and all polyethylene cemented socket, was used for THA implants. Basically the third generation cementing technique was used for THA using bone cement. The socket fixation was performed with bone cement (Endurance, DePuy) and hydroxyapatite (HA) granules (Ca10(PO4)6(OH)2, Boneceram P; G-2, Olympus, Japan). In original IBBC technique, HA granules were dispersed on reamed acetabulum before cementing. In M-IBBC technique, HA granules were attached to bone cement on plastic plate, then inserted to reamed acetabulum and pressurized. HA granules (G-2) are 0.3–0.6mm in size, with 35–38% porosity and sintered at 1150â��. 51 hip joints (49 cases) were operated between June 2010 and December 2011, and followed. The average follow-up was 3.9 years, and average age at operation was 66.5 years. The clinical results were evaluated by Japan Orthopaedic Association Hip Score (JOA score), and X-p findings were evaluated using antero-posterior radiographs. The locations of radiolucent lines were identified according to the zones described by Delee and Charnley for acetabular components, and Zone 1 was divided into two parts, outer Zone 1a and inner Zone 1b. Results and Discussion. Revision was not performed. Japanese orthopaedic association (JOA) score improved from 48 to 87. Socket and stem loosening was not observed. X-p findings of sockets demonstrated radiolucent line in Zone 1a/1b/2/3 in 2/0/0/0% immediately after the operation, 9.8/2/0/2% at 1 year postoperatively. After 1 year there was no progressive change, however, improvement of radiolucent line in Zone 1a was observed in two cases after 3 years postoperatively. Accordingly, after 3 years radiolucent line in Zone 1a/1b was observed in 5.9/2%. Oonish has reported excellent clinical results of THA with IBBC (1). To easily perform IBBC, we have modified the technique, improving the problems of IBBC. In our previous report, we reported improvement of radiolucent line in IBBC (2). In this report, the similar radiographic behavior was observed in M-IBBC, which was not observed in conventional cementing technique. This finding suggests osteoconductive property of hydroxyapatite granules at the interface after the operations. Conclusions. The interesting finding in M-IBBC cases was the improvement of radiolucent line, which was observed in IBBC cases. The promising long-term clinical results of M-IBBC method, similar to IBBC cases, were expected

Introduction:. Novel biomaterials may offer alternatives to metal arthroplasty bearings. To employ these materials in thin, bone conserving implants would require direct fixation to bone, using Titanium/HA coatings. Standard tests are used to evaluate the adhesion strength of coatings to metal substrates [1], versus FDA pass criteria [2]. In tensile adhesion testing, a disc is coated and uniform, uniaxial tension is exerted upon the coating-substrate interface; the strength is calculated from the failure load and surface area. Rapid failure occurs when the peak interface stress exceeds the adhesion strength, as local failure will propagate into an increasing tensile stress field. Ceramics and reinforced polymers (e.g. carbon-fibre-reinforced PEEK), have considerably different stiffness (E) and Poisson's Ratio (ν) from the coating and implant metals. We hypothesised that this substrate-coating stiffness mismatch would produce stress concentrations at the interface edge, well in excess of the uniform stress experienced with coatings on similar stiffness metals. Methodology:. The interface tensile stress field was predicted for the ASTM F1147 tensile strength test with a finite element analysis model, with a 500 μm thick coating (50 μm dense Ti layer, 450 μm porous Ti/HA/adhesive layer), bonded to a stainless steel headpiece with FM1000 adhesive (Fig. 1). Solutions were obtained for:. Configuration A: ASTM-standard geometry with Ti-6Al-4V (E = 110GPa, ν = 0.31), CoCrMo (E = 196GPa, ν = 0.30), ceramic (E = 350GPa, ν = 0.22, e.g. BIOLOX delta) and CFR-PEEK (E = 15GPa, ν = 0.41, e.g. Invibio MOTIS) substrates. Modified models were used to analyse oversized substrate discs:. Configuration B: coated fully and bonded to the standard diameter headpiece, and. Configuration C: Coated only where bonded to the headpiece. Results and Discussion:. The stiffness mismatch between the coating and the ceramic and CFR-PEEK substrates was predicted to introduce, respectively, a 1.80x and 3.57x stress concentration compared to a Ti6Al4V substrate (Fig. 2), thereby reducing the failure load for a given interface strength. These predictions consider the test stress distribution only, and do not assess the coating-substrate interface strength. However, the failure load is a function of the interface strength and the peak test stress, so the standard test and stress calculation for stiffness-mismatched substrates may indicate artificially low adhesion strength. The test may be modified to suit a particular material combination. As an example, for ceramic substrates the results indicate that an oversized, fully coated specimen (B) would experience stress closest to the standard's intended uniform stress field, suggesting that this configuration would be more appropriate. The stress distribution may be sensitive to the coating thickness, so tests should be verified accordingly. Conclusion:. The ASTM coating tensile adhesion strength test standard was predicted to generate a non-uniform interfacial stress for ceramic and polymer composite substrate materials. The standard may not be directly applicable for non-metal substrates as the stiffness mismatch needs to be considered

INTRODICTION. Since 1985, not resorbable crystalline osteoconductive hydroxyapatite (HA) granules were interposed on the interface between bone and bone cement at the cementation (Interface Bioactive Bone Cement: IBBC) of total hip arthoplasty (THA) to prevent generation of connective tissue and osteolysis for the longevity of cemented THA. To prevent the patients from infection, we are planning to use b-tricalcium phosphate (Beta-TCP) impregnated with antibiotics along with HA granules. However, there have been no reports on the loading and release of antibiotics from fine granules of Beta-TCP. Here, we have investigated the loading of antibiotics on Beta-TCP and their release in vivo. MATERIALS AND METHODS. Beta-TCP was impregnated with antibiotics such as flomoxef sodium (F), vancomycin hydrochloride (V) cefotiam dihydrochloride (C) and cefozopran hydrochloride (CE) under normal or reduced pressure. After washing with PBS three times, Beta-TCP loaded with the antibiotic was placed in PBS. An aliquot of solution was sampled at appropriate time intervals and the amount of the released antibiotic was estimated based on the anti-bacterial activity. RESULTS AND DISCUSSION. When drug loading was done by dropping the antibiotic solution to Beta-TCP granules, the amount of antibiotic released from 20 mg of HA was 8 μg forF, 0 μg for V, 6 μg for C and 520 μg for CE. Their release completed within 24 hrs. When the antibiotic loading was done under reduced pressure, 20 mg of Beta-TCP was loaded with 40 μg ofF, 130 μg of V and 25 μg of C, but the released amount was 16 μg for F, 8 μg for V and 0 μg forC. Each drug was released within 10 hrs. Meanwhile, 8000 μg of CE was loaded on 20 mg of Beta-TCP and its release continued for 6 days. When Beta-TCP loaded with C or CE was placed in 0.25 MEDTA to dissolve Beta-TCP gradually, the release of C and CE sustained over 14 days along with the dissolution of Beta-TCP. The release of C from Beta-TCP continued over 19 days in EDTA. The released amount of C and CE were 116 μg and 7100 μg, respectively. Thus, CE seemed the most suitable for our purpose in terms of the loaded amount and releasing behavior. However, CE as well as C showed the eminent sustained release in EDTA solution. Since Beta-TCP shows bioabsoption, it is expected to be efficient antibiotics carrier. It is worthy to use adequate sizes of Beta-TCP granules impregnated with antibiotics in combination with osteoconductive HA in IBBC for the protection of the infection after joint replacement, especially in revision surgery after infection

Femoral stress shielding in cementless THA is a potential complication commonly observed in cementless distally loading press-fit stems. Long-term metaphyseal fixation and proximal load transfer is desired. Is routine autologous metaphyseal bone impaction and proximal primary stability an answer to this goal?. This prospective study describes long-term femoral bone remodeling and load transfer in cementless THA at a mean of 17 years (range: 15 to 20 years) in 208 consecutive fully HA-coated stems (Corail). All primary THA were performed by one group of surgeons between 1986 and 1991. The concept of surgical technique included impaction of autologous metaphyseal bone using bland femoral broaches until primary stability was achieved without distal press-fit. Radiographic evaluation revealed a total of five (2.4%) stems with periprosthetic osteolysis, which were associated with eccentric polyethylene wear. They were either revised or awaiting revision. The remaining 97.6% stems revealed desired proximal load transfer in the metaphysis (52%) or in both metaphysis and diaphysis (48%). Distal stress shielding was not observed and was considered to be related to: impaction of metaphyseal bone, bland broaches, HA coating, and prosthetic design. Biological autologous bone impaction of the metaphysis provides both primary stem stability and successful longterm osteointegration with the Corail stem after 20 years. The surgical technique of proximal autologous bone impaction rather than extraction of cancellous bone material and the use of a fully HA coated stem without distal press-fit show encouraging longterm results in THA

Aim. The aim of this investigation was to compare risk of infection in both cemented and cementless hemiarthroplasty (HA) as well as total hip arthroplasty (THA) following femoral neck fracture. Methods. Data collection was performed using the German Arthroplasty Registry (EPRD) In HA and THA following femoral neck fracture fixation method was divided into cemented and cementless protheses and paired according to age, sex, body mass index (BMI), and the Elixhauser score using Mahalanobis distance matching. Results. Overall in 13,612 cases of intracapsular femoral neck fracture, with 9,110 (66.9 %) HAs and 4502 (33.1 %) THAs were analyzed. Infection rate in HA was significantly reduced in cases with use of antibiotic-loaded cement compared to cementless fixated prosthesis (p=0.013). In patients with THA no statistical difference between cemented and cementless prothesis was registered, however after one year 2.4 % of infections were detected in cementless and 2.1 % in cemented THA. In the subpopulation of HA after one year 1.9 % of infections were registered in cemented and 2.8 % in cementless HA. BMI (p=0.001) and Elixhauser-Comorbidity-Score (p<0.003) were identified as risk factors of PJI, while in THA also cemented prosthesis demonstrated within the first 30 days an increased risk (HR=2.728; p=0.010). Conclusion. The rate of infection after intracapsular femoral neck fracture was significantly reduced in patients treated by antibiotic-loaded cemented hemiarthroplasty. In particular for patients with multiple risk factors for the development of a PJI the usage of antibiotic-loaded bone cement seems to be a reasonable procedure for prevention of infection

Introduction. Total Hip Arthroplasty (THA) devices are now increasingly subjected to a progressively greater range of kinematic and loading regimes from substantially younger and more active patients. In the interest of ensuring adequate THA solutions for all patient groups, THA polyethylene acetabular liner (PE Liner) wear representative of younger, heavier, and more active patients (referred to as HA in this study) warrants further understanding. Previous studies have investigated HA joint related morbidity [1]. Current or past rugby players are more likely to report osteoarthritis, osteoporosis, and joint replacement than a general population. This investigation aimed to provide a preliminary understanding of HA patient specific PE liner tribological performance during Standard Walking (SW) gait in comparison to IS0:14242-1:2014 standardized testing. Materials and Methods. Nine healthy male subjects volunteered for a gait lab-based study to collect kinematics and loading profiles. Owing to limitations in subject selection, five subjects wore a weighted jacket to increase Body Mass Index ≥30 (BMI). An induced increase in Bodyweight was capped (<30%BW) to avoid significantly effecting gait [3] (mean=11%BW). Six subjects identified as HA per BMI≥30, but with anthropometric ratios indicative of lower body fat as previously detailed by the author [2] (Waist-to-hip circumference ratio and waist circumference-to-height ratio). Three subjects identified as Normal (BMI<25). Instrumented force plate loading profiles were scaled (≈270%BW) in agreement with instrumented hip force data [4]. A previously verified THA (Pinnacle® Marathon® 36×56mm, DePuy Synthes) Finite Element Analysis wear model based on Archard's law and modified time hardening model [5] was used to predict geometrical changes due to wear and deformation, respectively (Figure 1). Subject dependent kinematic and loading conditions were sampled to generate, for both legs, 19 SW simulation runs using a central composite design of response surface method. Results. HA group demonstrated comparable SW gait characteristics and Range of Motion (RoM) to the Normal group (p>0.1) (Figure 2) but statistically greater SW peak loads, PE liner wear rates, deformation, and penetration after 3Mc (Million cycles) of SW (p<0.01). HA group demonstrated comparable RoM (p>0.4) and peak loading to ISO-14242-1:2014 (p>0.1) although, up to 8° increase in flexion-extension angle was observed. The HA group demonstrated statistically greater wear rates (mean 7.5% increase) to ISO-14242-1:2014 (p<0.05) (Figure 3). No difference in PE liner deformation or penetration was observed (p>0.4). Discussion. This study detailed only a 19. th. percentile within a broader HA population (BW=91kg, n=485) [6] however, were statistically worst-case compared to a Normal group and ISO-14242-1:2014. A 95. th. percentile HA population (BW=127kg) may produce lower PE liner tribological performance than reported in this investigation and therefore, warrants further investigation. Further studies would be beneficial to determine whether the increase in PE liner wear rate for HA patients is predictable based on kinematics and loading alone, or whether influences exist in design inputs and surgical factors. Conclusion. The HA population detailed in this study (representative of a 19. th. percentile) demonstrated statistically greater SW PE liner wear rates compared to ISO-14242-1:2014. This study may have implications for the test methods considered appropriate to verify novel designs. For any figures or tables, please contact the authors directly

Displaced femoral neck fractures can have devastating impacts on quality of life and patient function. Evidence for optimal surgical approach is far from definitive. The Hip Fracture Evaluation with Alternatives of Total Hip Arthroplasty versus Hemi-Arthroplasty (HEALTH) trial aimed to evaluate unplanned secondary procedures following total hip arthroplasty (THA) versus hemi-arthroplasty (HA) within two years of initial surgery for displaced femoral neck fractures. Secondary objectives evaluated differences in patient function, health-related quality of life, mortality, and hip-related complications HEALTH is a large randomized controlled trial that included 1,495 patients across 81 centers in 10 countries. Patients aged 50 years or older with displaced femoral neck fractures received either THA or HA. Participants were followed for 24 months post-fracture and a Central Adjudication Committee adjudicated fracture eligibility, technical placement of prosthesis, additional surgical procedures, hip-related complications, and mortality. The primary analyses were a Cox proportional hazards model with time to the primary study endpoint as the outcome and THA versus HA as the independent variable. Using multi-level linear models with three levels (centre, patient, and time), with patient and centre entered as random effects, the effect of THA versus HA on quality of life (Short Form-12 (SF-12) and EQ-5D), function (Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)), and mobility (Timed Up and Go Test (TUG)) were estimated separately. The majority of patients were female (70.1%), 70 years of age or older (80.2%), and able to ambulate without the aid of an assistive device before their fracture (74.4%), and the injury in the majority of the patients was a subcapital femoral neck fracture (61.9%). The primary end point occurred in 57 of 718 patients (7.9%) who were randomly assigned to THA and 60 of 723 patients (8.3%) who were randomly assigned to HA (hazard ratio, 0.95; 95% confidence interval [CI], 0.64 to 1.40; p=0.79). Hip instability or dislocation occurred in 34 patients (4.7%) assigned to total hip arthroplasty and 17 patients (2.4%) assigned to hemi- arthroplasty (hazard ratio, 2.00; 99% CI, 0.97 to 4.09). Function, as measured with the total WOMAC total score, pain score, stiffness score, and function score, modestly favored THA over HA. Mortality was similar in the two treatment groups (14.3% among the patients assigned to THA and 13.1% among those assigned to HA, p=0.48). Serious adverse events occurred in 300 patients (41.8%) assigned to THA and in 265 patients (36.7%) assigned to HA. Among independently ambulating patients with displaced femoral neck fractures, the incidence of secondary procedures did not differ significantly between patients who were randomly assigned to undergo THA and those who were assigned to undergo HA, and THA provided a clinically unimportant improvement over HA in function and quality of life over 24 months

Aim. Bone and implant-associated infections caused by microorganisms that grow in biofilm are difficult to treat because of persistence and recurrence. Systemic administration of antibiotics is often inefficient because the poor vascularization of the site of infection. This issue has led to the development of biomaterials capable to locally deliver high doses of therapeutic agents to the injured bone with minimal systemic effects. In this context, calcium sulphate/hydroxyapatite (CS/HA) bone graft substitutes are widely used being safe, osteoconductive and resorbable biomaterials that can be easily enriched with consistent amounts of antibiotics. In this in vitro study, the capability of the eluted antibiotics to select the tested bacterial strains for antibiotic resistance was evaluated to confirm the safe use of the product. Method. S. aureus, S. epidermidis and P. aeruginosa isolated in our Institute from bone and joint infection with different resistance phenotypes were used. 6 × 2.5 mm CS/HA discs were generated by pouring the antibiotic loaded formulations in a mold and were used as a modified disk diffusion test. The resistance selection was evaluated by subculturing cells growing on the edge of the zone of inhibition (ZOI) for seven days. Minimum inhibitory concentrations (MICs) of gentamicin and vancomycin were determined by broth microdilution method before and after the selection of resistance assay. In addition, MICs were assessed after seven day passage on antibiotic free agar plates to evaluate if eventual decrease of antibiotic susceptibility was stable or only transient. Results. Commonly, no adaptation in presence of both CS/HA formulations was observed by analysing ZOI on agar medium. The kinetic of decrease of the ZOI was similar between the strains, with the exception of gentamicin resistant staphylococci in presence of gentamicin loaded CS/HA, which was faster with respect to the susceptible strains. Conclusions. The present study shows that elution of gentamicin and vancomycin from CS/HA bone graft substitutes did not induce a decrease in susceptibility to these antibiotics in an in vitro setting, suggesting the safe use of the product

Osteochondral (OC) defects of the knee are associated with pain and significant limitation of activity. Studies have demonstrated the therapeutic efficacy of mesenchymal stem cell (MSC) therapies in treating osteochondral defects. There is increasing evidence that the efficacy of MSC therapies may be a result of the paracrine secretion, particularly exosomes. Here, we examine the effects of MSC exosomes in combination with Hyaluronic Acid (HA) as an injectable therapy on functional osteochondral regeneration in a rabbit osteochondral defect model. Exosomes were purified from human MSC conditioned medium by size fractionation. A circular osteochondral defect of 4.5 mm diameter and 2.5 mm depth was surgically created in the trochlear grooves of 16 rabbit knees. Thereafter, eight knees received three weekly injections of 200 µg of exosomes in one ml of 3% HA, and the remaining eight knees received three weekly injections of one ml of 3% HA only. The rabbits were sacrificed at six weeks. Analyses were performed by macroscopic and histological assessments, and functional competence was analysed via Young Modulus calculation at five different points (central, superior, inferior, medial and lateral) of the repaired osteochondral defect site. MSC exosomes displayed a modal size of 100 nm and expressed exosome markers (CD81, TSG101 and ALIX). When compared to HA alone, MSC exosomes in combination with HA showed significantly better repair histologically and biomechanically. The Young Modulus was higher in 4 out of the 5 points. In the central region, the Young Modulus of MSC exosome and HA combination therapy was significantly higher: 5.42 MPa [SD=1.19, 95% CI: 3.93–6.90] when compared to HA alone: 2.87 MPa [SD=2.10, 95% CI: 0.26–5.49], p < 0 .05. The overall mean peripheral region was also significantly higher in the MSC exosome and HA combination therapy group: 5.87 MPa [SD=1.19, 95% CI: 4.40–7.35] when compared to HA alone: 2.70 MPa [SD=1.62, 95% CI: 0.79–4.71], p < 0 .05. The inferior region showed a significantly higher Young Modulus in the combination therapy: 7.34 MPa [SD=2.14, 95% CI: 4.68–10] compared to HA alone: 2.92 MPa [SD=0.98, 95% CI: 0.21–5.63], p < 0.05. The superior region showed a significantly higher Young Modulus in the combination therapy: 7.31 MPa [SD=3.29, 95% CI: 3.22–11.39] compared to HA alone: 3.59 MPa [SD=2.55, 95% CI: 0.42–6.76], p < 0.05. The lateral region showed a significantly higher Young Modulus in the combination therapy: 8.05 MPa [SD=2.06, 95% CI: 5.49–10.61] compared to HA alone: 3.56 MPa [SD=2.01, 95% CI: 1.06–6.06], p < 0.05. The medial region showed a higher Young Modulus in the combination therapy: 6.68 MPa [SD=1.48, 95% CI: 4.85–8.51] compared to HA alone: 3.45 MPa [SD=3.01, 95% CI: −0.29–7.19], but was not statistically significant. No adverse tissue reaction was observed in all the immunocompetent animals treated with MSC exosomes. Three weekly injections of MSC exosomes in combination with HA therapy results in a more functional osteochondral regeneration as compared to HA alone

Abstract. Introduction. The extent to which hip arthroscopy (HA) treatments influence sexual function is not well described and limited to small cohorts. This study aims to describe trends in self-reported reported sexual function before and after HA. Methods. Adult (≥18 years) patients who underwent HA between 1/01/2012 and 31/10/2020 were extracted from the UK Non-Arthroplasty Hip Registry. International Hip Outcome Tool 12 (iHOT-12) questionnaires were collected pre-operatively and at 6 and 12 months. The iHOT-12 then asks asking patients to quantify ‘how much trouble they experience with sexual activity because of their hip?’ with responses converted to a continuous scale (0–100) to measure function. Results. Of 7639 procedures (59% female, mean age 36.5 years (SD 11)), 91% (5616 of 6151 respondents) indicated pre-operatively that questions about sexual activity were relevant to them (male 93%, female 90%, p < 0.001). Overall, mean pre-operative sexual function increased from 42.0 (95%CI 41.2 to 42.8, n=5267) to 61.8 (60.6 to 63.1, n=2393) at 6 months, and 62.1 (60.8 to 63.5, n=2246) at 12 months post-operatively. At 12 months, both sexes saw significant improvement in their pre-operative sexual function scores (p<0.0001). Males started from significantly higher baseline sexual function (53.3 vs 34.2) and achieved higher scores by 12 months (68.8 vs 58.0) compared to female patients. There was no significant difference in pre- or post-operative scores when comparing younger (<40 years) and older (>40 years). Conclusions. Most patients can expect to experience improvement in their sexual function following hip arthroscopy, regardless of sex or age group

The treatment of paediatric supracondylar humeral fractures is likely one of the first procedures involving X-ray guided wire insertion that trainee orthopaedic surgeons will encounter. Pinning is a skill that requires high levels of anatomical knowledge, spatial awareness, and hand-eye coordination. We developed a simulation model using silicone soft-tissue and 3D-printed bones to allow development and practice of this skill at no additional risk to patients. For this model, we have focused on reusability and lowering raw-material costs without compromising fidelity.

To achieve this, the initial bone model was extracted from open-source computed tomography scans and modified from adult to paediatric size. Muscle of appropriate robustness was then sculpted around the bones using 3D modelling software. A cutaneous layer was developed to mimic oedema using clay sculpturing on a plaster-casted paediatric forearm. These models were then used for 3D-printing and silicone casting respectively. The bone models were printed with settings to imitate cortical and cancellous densities and give high-fidelity tactile feedback upon drilling. Each humerus costs NZD $0.30 in material to print and can be used 1–3 times. Silicone casting of the soft-tissue layers imitates differing relative densities between muscle and oedematous cutaneous tissue, thereby increasing skill necessary to accurately palpate landmarks. Each soft-tissue sleeve cost NZD $70 in material costs to produce and can be used 20+ times.

The resulting model is modular, reusable, and replaceable, with each component standardised and easily reproduced. It can be used to practice land-mark palpation and Kirschner wire pinning and is especially valuable in smaller centres which may not be able to afford traditional Saw Bones models. This low-cost model thereby improves equity while maintaining quality of simulation training.

to determine the extent of Orthobullets use by orthopaedic residents in academic and clinical settings. We also wanted to determine whether its widespread use is the same in various training programs around the world and so we chose to survey two distinct programs without any academic or institutional ties.

An electronic 9 question survey created using SurveyMonkey was sent to residents in two distinct Orthopaedic residency programs, either via text message or by email. The two programs surveyed were the McGill University Orthopaedic Surgery residency program located in Montreal, Canada, and the Oman Medical Specialty Board (OMSB) Orthopaedic Surgery residency program located in Muscat, Oman.

A total of 36 residents, 20 from McGill and 16 from OMSB, responded to the survey request. In both programs, 89% of all the residents surveyed claimed they use Orthobullets at least 4 times per week, and greater than 95% of them use it during call shifts to obtain information rapidly. Regarding the use of Orthobullets in the context of operating theatre case preparation, over 50% of residents claim to use it often while only 25% claim to rarely use it for this purpose. The use of Orthobullets during clinics seemed to be the least popular among residents as 47% claimed they rarely use it. Cumulatively in both programs, more than 80% of residents indicated that they always use Orthobullets in preparation for an exam especially among senior residents. Approximately two thirds of residents have said they completely trust the information provided on Orthobullets, with the remainder indicating that they trust Orthobullets more than 75% of the time. The proportion of residents who indicated that they completely trust Orthobullets was greater in the OMSB group (75%) and among senior trainees. Over 85% of residents discovered Orthobullets through friends and colleagues, and the rest through the program and faculty members.

Our survey results demonstrate the widespread use of Orthobullets, a popular online orthopaedic resource, among orthopaedic residents of all levels. The settings in which Orthobullets was most used were exam preparation and during call shifts. In addition, with the high amount of confidence residence have Orthobullets, it is questionable as to how many are actually aware that its information is not validated. For the time being however, we do not discourage the use of Orthobullets for exam preparation, however, we recommend that programs warn their residents to abstain from using it in their clinical decision-making until it has demonstrated peer-reviewed approval.

Introduction. Hip arthroplasty is considered common to patients aged 65 and over however, both Jennings, et al., (2012) and Bergmann (2016) found THA patients are substantially younger with more patients expecting to return to preoperative activity levels. With heavier, younger, and often more active patients, devices must be able to support a more demanding loading-regime to meet patient expectations. McClung (2000) demonstrated that obese patients can display lower wear-rates with UHMWPE bearing resulting from post-operative, self-induced reduced ambulatory movement, thus questioning if obese kinematics and loading are indeed the worst-case. Current loading patterns used to test hip implants are governed by ISO 14242-1 (2014). This study aimed to characterize a heavy and active population (referred to as HA) and investigate how the gait profile may differ to the current ISO profile. Method. A comprehensive anthropometric data set of 4082 men (Gordon, CC., et.al., 2014) was used to characterize a HA population. Obese and HA participants were classed as BMI ≥30 however HA participants were identified by applying anthropometric ratios indicative of lower body fat, namely “waist to height” (i.e. WHtR <0.6) and “waist to hip” (i.e. WHpR <0.9). Findings. Of 491 obese participants 61 were identified as HA (i.e. BMI> 30, WHpR<0.9; WHtR<0.6) (Figure 1). These characteristics were validated against a population of elite rugby players that were found to be a true reflection of HA patients (Figure 2). Combining the Army and Rugby populations resulted in a weight of 123kg for the 95. th. percentile, which based on 3× body weight (as referenced in ISO14242-1) would equate to a peak simulator load of 3620N. Conclusion. Characterization of a HA population was successfully defined as clinically obese by BMI, but with WHtR and WHpR associated with lower body fat. The author was unable to identify gait characteristics of a HA population through existing literature. Future Work. A gait-lab based study will be used to compare literature-based kinematics of obese subjects to those of HA subjects. A worst-case gait cycle can then be established for standard walking and other activities and translated into hip simulator parameters for HA patients

Primary hip and knee joint replacements in Canada have been estimated to cost over $1.4 billion dollars annually, with revision surgery costing $177 million. The most common cause of revision arthroplasty surgery in Canada is infection. Periprosthetic joint infections (PJIs) are a devastating though preventable complication following arthroplasty. Though variably used, antibiotic laden bone cement (ALBC) has been demonstrated to decrease PJIs following primary total knee arthroplasty (TKA). Unfortunately, ALBC is costlier than regular bone cement (RBC). Therefore, the aim of this study was to determine if the routine use of ALBC in primary TKA surgery is a cost-effective practice from the perspective of the Canadian healthcare system.

A decision tree was constructed using a decision analysis software (TreeAge Software, Williamstown, Massachusetts) to a two-year time horizon comparing primary TKA with either ALBC or RBC from the perspective of a single-payer healthcare system. All costs were in 2020 Canadian dollars. Health utilities were in the form of quality adjusted life years (QALYs). Model inputs for cost were derived from regional and national databases. Health utilities and probability parameters were derived from the latest literature. One-way deterministic sensitivity analysis was performed on all model parameters. The primary outcome of this analysis was an incremental cost-effectiveness ratio (ICER) with a willingness-to-pay (WTP) threshold of $50,000 per QALY.

Primary TKA with ALBC (TKA-ALBC) was found to be more cost-effective compared to primary TKA with RBC (TKA-RBC). More specifically, TKA-ALBC dominated TKA-RBC as it was less costly on the long term ($11,160 vs. $11,118), while providing the same QALY (1.66). The ICER of this cost-utility analysis (CUA) was $-11,049.72 per QALY, much less than the WTP threshold of $50,000 per QALY. The model was sensitive to costs of ALBC-TKA as well as the probability of PJI following ALBC-TKA and RBC-TKA. ALBC ceased to be cost effective once the cost of ALBC was greater than $223.08 CAD per bag of cement.

The routine use of ALBC in primary TKA is a cost-effective practice in the context of the Canadian healthcare system as long as the cost of ALBC is maintained at a reasonable price and the published studies to-date keep supporting the efficacy of ALBC in decreasing PJI following primary TKA. Further, this analysis is very conservative, and ALBC is likely much more cost-effective than presented. This is due to this model's revision surgery cost parameter being based on the average cost of all revision TKA surgery in Canada, regardless of etiology. Considering many PJIs require two-stage revisions, the cost parameter used in this analysis for revision surgery is an underestimate of true cost. Ultimately, this is the first cost-effectiveness study evaluating this topic from the perspective of the Canadian healthcare system and can inform future national guidelines on the subject matter.

Dual mobility is a French concept that appeared in the 1970s and was initially intended to reduce dislocation rates. In recent years, this concept has evolved with new HA titanium spray coatings, new external macrostructures, and better-quality polyethylene. This has allowed to extend the indications to younger and therefore active populations. The objective of our work is to analyze at least 10 years a homogeneous and continuous series of 170 primary total hip replacements associating a latest generation Novae Sunfit. ®. dual mobility cup with a straight femoral stem. Only primary arthroplasties for osteoarthritis or necrosis were included. Total hip arthroplasty was always performed through a posterolateral approach. All patients had regular clinical and radiological follow-up. The average follow-up in our series was 11.5 years. The average age of the population is 71 years. At the last follow-up, there were 17 deaths, 6 losses to follow up and 9 adverse events, including 1 cup change for psoas impingement and 1 dislocation. The low rate of dislocation at 11 years confirms the high stability of the dual mobility, which should be recommended for primary procedure for patients at high risk of postoperative instability. The lack of intraprosthetic dislocation due to wear at 11 years of follow-up highlights the good quality of the latest generation of polyethylene, and the need to combine high-polished surfaces and a refined femoral neck with a dual mobility cup. Finally, the lack of aseptic loosening confirms the quality of the secondary fixation of these implants and justifies their wider use in all patients