Aims. Both the femoral and tibial component are usually cemented at revision total knee arthroplasty (rTKA), while stems can be added with either cemented or press-fit (hybrid) fixation. The aim of this study was to compare the long-term stability of rTKA with cemented and press-fitted stems, using radiostereometric analysis (RSA). Methods. This is a follow-up of a randomized controlled trial, initially involving 32 patients, of whom 19 (nine cemented, ten hybrid) were available for follow-up ten years postoperatively, when further RSA measurements were made. Micromotion of the femoral and tibial components was assessed using model-based RSA software (RSAcore). The clinical outcome was evaluated using the Knee Society Score (KSS), the Knee injury and Osteoarthritis Outcome Score (KOOS), and visual analogue scale (pain and satisfaction). Results. The median total femoral translation and rotation at ten years were 0.39 mm (interquartile range (IQR) 0.20 to 0.54) and 0.59° (IQR 0.46° to 0.73°) for the cemented group and 0.70 mm (IQR 0.15 to 0.77) and 0.78° (IQR 0.47° to 1.43°) for the hybrid group. For the tibial components this was 0.38 mm (IQR 0.33 to 0.85) and 0.98° (IQR 0.38° to 1.34°) for the cemented group and 0.42 mm (IQR 0.30 to 0.52) and 0.72° (IQR 0.62° to 0.82°) for the hybrid group. None of these values were significantly different between the two groups and there were no significant differences between the clinical scores in the two groups at this time. There was only one re-revision, in the hybrid group, for infection and not for aseptic loosening. Conclusion. These results show good long-term fixation with no difference in micromotion and clinical outcome between fully cemented and hybrid fixation in rTKA, which builds on earlier short- to mid-term results. The patients all had type I or II osseous defects, which may in part explain the good results. Cite this article: Bone Joint J 2022;104-B(7):875–883

For chondral damage in younger patients, surgical best practice is microfracture, which involves drilling into the bone to liberate the bone marrow. This leads to a mechanically inferior fibrocartilage formed over the defect as opposed to the desired hyaline cartilage that properly withstands joint loading. While some devices have been developed to aid microfracture and enable its use in larger defects, fibrocartilage is still produced and there is no clear clinical improvement over microfracture alone in the long term. Our goal is to develop 3D printed devices, which surgeons can implant with a minimally invasive technique. The scaffolds should match the functional properties of cartilage and expose endogenous marrow cells to suitable mechanobiological stimuli in-situ, in order to promote healing of articular cartilage lesions before they progress to osteoarthritis, and rapidly restore joint health and mobility. Importantly, scaffolds should direct a physiological host reaction, instead of a foreign body reaction, associated with chronic inflammation and fibrous capsule formation, negatively influencing the regenerative outcome. Our novel silica/polytetrahydrofuran/polycaprolactone hybrids were prepared by sol-gel synthesis and scaffolds were 3D printed by direct ink writing. 3D printed hybrid scaffolds with pore channels of ~250 µm mimic the compressive behaviour of cartilage. Our results show that these scaffolds support human bone marrow stem/stromal cell (hMSC) differentiation towards chondrogenesis in vitro under hypoxic conditions to produce markers integral to articular cartilage-like matrix evaluated by immunostaining and gene expression analysis. Macroscopic and microscopic evaluation of subcutaneously implanted scaffolds in mice showed that scaffolds caused a minimal resolving inflammatory response. Our findings show that 3D printed hybrid scaffolds have the potential to support cartilage regeneration. Acknowledgements: Authors acknowledge funding provided by EPSRC grant EP/N025059/1

The demand for revision total knee arthroplasty (TKA) has grown significantly in recent years. The two major fixation methods for stems in revision TKA include cemented and ‘hybrid’ fixation. We explore the optimal fixation method using data from recent, well-designed comparative studies. We performed a systematic review of comparative studies published within the last 10 years with a minimum follow-up of 24 months. To allow for missing data, a random-effects meta-analysis of all available cases was performed. The odds ratio (OR) for the relevant outcome was calculated with 95% confidence intervals. The effects of small studies were analyzed using a funnel plot, and asymmetry was assessed using Egger's test. The primary outcome measure was all-cause failure. Secondary outcome measures included all-cause revision, aseptic revision and radiographic failure. There was a significantly lower failure rate for hybrid stems when compared to cemented stems (p = 0.006) (OR 0.61, 95% CI 0.42-0.87). Heterogeneity was 4.3% and insignificant (p = 0.39). There was a trend toward superior hybrid performance for all other outcome measures including all-cause re-revision, aseptic re-revision and radiographic failure. Recent evidence suggests a significantly lower failure rate for hybrid stems in revision TKA. There is also a trend favoring the use of hybrid stems for all outcome variables assessed in this study. This is the first time a significant difference in outcome has been demonstrated through systematic review of these two modes of stem fixation. We therefore recommend the use, where possible, of hybrid stems in revision TKA

Introduction and Objective. Alveolar bone resorption following tooth extraction or periodontal disease compromises the bone volume required to ensure the stability of an implant. Guided bone regeneration (GBR) is one of the most attractive technique for restoring oral bone defects, where an occlusive membrane is positioned over the bone graft material, providing space maintenance required to seclude soft tissue infiltration and to promote bone regeneration. However, bone regeneration is in many cases impeded by a lack of an adequate tissue vascularization and/or by bacterial contamination. Using simultaneous spray coating of interacting species (SSCIS) process, a bone inspired coating made of calcium phosphate-chitosan-hyaluronic acid was built on one side of a nanofibrous GBR collagen membrane in order to improve its biological properties. Materials and Methods. First, the physicochemical characterizations of the resulting hybrid coating were performed by scanning electron microscopy, X-ray photoelectron, infrared spectroscopies and high-resolution transmission electron microscopy. Then human mesenchymal stem cells (MSCs) and human monocytes were cultured on those membranes. Biocompatibility and bioactivity of the hybrid coated membrane were respectively evaluated through MSCs proliferation (WST-1 and DNA quantification) and visualization; and cytokine release by MSCs and monocytes (ELISA and endothelial cells recruitment). Antibacterial properties of the hybrid coating were then tested against S. aureus and P. aeruginosa, and through MSCs/bacteria interactions. Finally, a preclinical in vivo study was conducted on rat calvaria bone defect. The newly formed bone was characterized 8 weeks post implantation through μCT reconstructions, histological characterizations (Masson's Trichrome and Von Kossa stain), immunohistochemistry analysis and second harmonic generation. Biomechanical features of newly formed bone were determined. Results. The resulting hybrid coating of about 1 μm in thickness is composed of amorphous calcium phosphate and carbonated poorly crystalline hydroxyapatite, wrapped within chitosan/hyaluronic acid polysaccharide complex. Hybrid coated membrane possesses excellent bioactivity and capability of inducing an overwhelmingly positive response of MSCs and monocytes in favor of bone regeneration. Furthermore, the antibacterial experiments showed that the hybrid coating provides contact-killing properties by disturbing the cell wall integrity of Gram-positive and Gram-negative bacteria. Its combination with MSCs, able to release antibacterial agents and mediators of the innate immune response, constitutes an excellent strategy for fighting bacteria. A preclinical in vivo study was therefore conducted in rat calvaria bone defect. μCT reconstructions showed that hybrid coated membrane favored bone regeneration, as we observed a two-fold increase in bone volume / total volume ratios vs. uncoated membrane. The histological characterizations revealed the presence of mineralized collagen (Masson's Trichrome and Von Kossa stain), and immunohistochemistry analysis highlighted a bone vascularization at 8 weeks post-implantation. However, second harmonic generation analysis showed that the newly formed collagen was not fully organized. Despite a significant increase in the elastic modulus of the newly formed bone with hybrid coated membrane (vs. uncoated membrane), the obtained values were lower than those for native bone (approximately 3 times less). Conclusions. These significant data shed light on the regenerative potential of such bioinspired hybrid coating, providing a suitable environment for bone regeneration and vascularization, as well as an ideal strategy to prevent bone implant-associated infections

Multiple joint registries have reported better implant survival for patients aged >75 years undergoing total hip arthroplasty (THA) with cemented implant combinations when compared to hybrid or uncemented implant combinations. However, there is considerable variation within these broad implant categories, and it has therefore been suggested that specific implant combinations should be compared. We analysed the most common contemporary uncemented (Corail/Pinnacle), hybrid (Exeter V40/Trident) and cemented (Exeter V40/Exeter X3) implant combinations in the New Zealand Joint Registry (NZJR) for patients aged >75 years. All THAs performed using the selected implants in the NZJR for patients aged >75 years between 1999 and 2018 were included. Demographic data, implant type, and outcome data including implant survival, reason for revision, and post-operative Oxford Hip Scores were obtained from the NZJR, and detailed survival analyses were performed. Primary outcome was revision for any reason. Reason for revision, including femoral or acetabular failure, and time to revision were recorded. 5427 THAs were included. There were 1105 implantations in the uncemented implant combination group, 3040 in the hybrid implant combination group and 1282 in the cemented implant combination group. Patient reported outcomes were comparable across all groups. Revision rates were comparable between the cemented implant combination (0.31 revisions/100 component years) and the hybrid implant combination (0.40 revisions/100 component years) but were statistically significantly higher in the uncemented implant combination (0.80/100 component years). Femoral-sided revisions were significantly greater in the uncemented implant combination group. The cemented implant and hybrid implant combinations provide equivalent survival and functional outcomes in patients aged over 75 years. Caution is advised if considering use of the uncemented implant combination in this age group, predominantly due to a higher risk of femoral sided revisions. The authors recommend comparison of individual implants rather than broad categories of implants

Studies have shown that 10–30% patients do not achieve optimal function outcomes after total hip replacement (THR). High quality randomised controlled trials (RCTs) evaluating the clinical and cost-effectiveness of techniques to improve functional outcomes after THR are lacking. We performed this study to evaluate the feasibility of a RCT comparing patient-reported functional outcomes after hybrid or fully cemented THR (ISRCTN11097021). Patients were recruited from two centres and randomised to receive either a fully cemented or hybrid THR. Data collection included Patient Reported Outcome Measures (PROMs), non-serious adverse events of special interest (AESI), serious adverse device effects (SADE) and NHS resource use. Qualitative interviews were undertaken to understand a) patient experiences of study processes and their reasons for taking part or not, and b) to understand surgeons’ perceptions of the study, factors affecting willingness to participate, and barriers to implementation of the future RCT findings. The target of 40 patients were successfully recruited for the feasibility RCT; the ratio of successful recruitment to eligible patients was 0.61 across both sites. Treatment crossovers occurred in four patients, all related to bone quality. Four patients were withdrawn due to not undergoing surgery within the study window because of the pandemic. Follow-up was 100% and PROMs were completed by all patients at all time points. The feasibility of conducting a within-trial cost-utility analysis was demonstrated. Interviews were conducted with 27 patients and 16 surgeons. Patients and surgeons generally found the study procedures acceptable and workable. Some declined participation because they did not want treatment allocated at random, or because blinding was off-putting. Surgeons’ perceptions of equipoise varied, and implementation of findings from the future RCT would need to recognise the ‘craft’ nature of surgery and the issue of training. We conclude that a full RCT with economic analysis will be both feasible and practicable, although mechanisms to safely implement potential changes to practice because of RCT findings may need consideration by the wider arthroplasty community

Hyaluronic acid (HA) is responsible for the viscoelastic properties of synovial fluid and cartilage. Compared to healthy joints, synovial fluid in osteoarthritic joints contains HA of lower concentration and molecular weight. Hyaluronic acid hybrid complexes are composed by long and short HA chains linked by H bonds. These rheological characteristics and viscoelastic properties were produced by thermal patented process without chemical modification. Chondroitin sulfate (CS) is one of the essential components of the articular cartilage matrix and plays a key role in cartilage's mechanical and elastic properties. Biotechnological chondroitin (CB) is produced through fermentative/biotechnological processes and, unlike CS, is not sulfated. It has been shown that CB to play a more significant role in the phenotypic maintenance of chondrocytes than chondroitin sulfate and increases their viability and proliferation. A recent A Single-Arm, Open-Label, Pilot Study was conducted to evaluate the safety and efficacy of a single-dose intra-articular injection of Hybrid Hyaluronic acid and Sodium Chondroitin in the Treatment of Symptomatic Hip Osteoarthritis. A single injection of HS-SC was well tolerated and safe in the treatment of symptomatic hip OA. The treatment demonstrated a rapid significant improvement in pain (VAS) and function (Lequesne's Index) up to 6 months of follow-up

Introduction. Traditionally correction of idiopathic paediatric scoliosis is done by hybrid fixation. This involves a judicious combination of mono-axial and poly-axial screw constructs. This has inherent perceived advantages with better deformity correction and maintaining alignment without loss of correction over time. Study design. Single centre retrospective review of prospective collected data on the radiological analysis of idiopathic paediatric scoliosis corrections. The study compared hybrid screw constructs (poly-axial & mono-axial) to all poly-axial screw constructs over 28 months. Objective. Compare loss of correction between hybrid screw construct group (HSG) and all poly-axial screw construct group (PSG). Method. Retrospective review of preoperative, post-operative and latest follow-up radiographs on the cohort of 42 consecutive patients over a period of 28 months from a single surgeon series. Results. There were 19 patients (16 females, 3 male) in HSG and 23 (18 females, 5 male) in PSG. Average age at surgery was 14 years for HSG and 15.8 years for PSG. The average baseline Cobbs angle for HSG was 64.57°and 60.79° for PSG. In the HSG, on average 11.6 levels were fused and, in the PSG, it was 11.3 level. Mean screw density for HSG was 1.54 and PSG was 1.6. Mean correction from pre-op to immediate post-op was 46.06° (70.10%) in the HS group and 41.24 degrees (67.78%) in the PS group. At the last follow-up, mean correction was 45.12° (68.0%) for the HSG and 42.43° (70.39%) for PSG. Loss of correction from post-operative radiographs to latest follow up averaged 10.05% in HSG and 3.86% for PSG. Discussion. All poly-axial screw constructs has the advantage of minimal tray inventory, simple logistics, decreased surgical time and overall better efficiency. Rod application and derotation over poly-axial screw constructs is well controlled and we found no difference in the performance of these screws during and after the procedure. Conclusion. There was no statistically significant difference in the degree or loss of correction in HSG or PSG. No difference in radiological outcomes. In poly-axial pedicle screw construct, threading the rod and correction manoeuvres are easier and thereby reducing surgical times. There was no compromise on the derotation manoeuvre and correction of the apical rotation deformity. Our findings show that all poly-axial screw constructs in the management of idiopathic scoliosis corrections is emerging as a tangible alternative for the future

Rotator cuff tears are common, with failure rates of up to 94% for large and massive tears. 1. For such tears, reattachment of the musculotendinous unit back to bone is problematic, and any possible tendon-bone repair heals through scar tissue rather than the specially adapted native enthesis. We aim to develop and characterise a novel soft-hard tissue connector device, specific to repairing/bridging the tendon-bone injury in significant rotator cuff tears, employing decellularised animal bone partially demineralised at one end for soft tissue continuation. Optimisation samples of 15×10×5mm. 3. , trialled as separate cancellous and cortical bone samples, were cut from porcine femoral condyles and shafts, respectively. Samples underwent 1-week progressive stepwise decellularisation and a partial demineralisation process of half wax embedding and acid bathing. Characterisations were performed histologically for the presence/absence of cellular staining in both peripheral and central tissue areas (n=3 for each cortical/cancellous, test/PBS control and peripheral/central group), and with BioDent reference point indentation (RPI) for pre- and post-processing mechanical properties. Histology revealed absent cellular staining in peripheral and central cancellous samples, whilst reduced in cortical samples compared to controls. Cancellous samples decreased in wet mass after decellularisation by 45.3% (p<0.001). RPI measurements associated with toughness (total indentation depth, indentation depth increase) and elasticity (1st cycle unloading slope) showed no consistent changes after decellularisation. X-rays confirmed half wax embedding provided predictable control of the mineralised-demineralised interface position. Initial optimisation trials show proof-of-concept of a soft-hard hybrid scaffold as an immune compatible xenograft for irreparable rotator cuff tears. Decellularisation did not appreciably affect mechanical properties, and further biological, structural and chemical characterisations are underway to assess validity before in vivo animal trials and potential clinical translation

We compared the long-term clinical and radiological results of hybrid total hip replacement (THR) with metal-on-metal Birmingham hip resurfacing (BHR) in two groups of 54 young patients matched for age, gender, body mass index and pre-operative levels of activity. The clinical outcome was assessed by the University of California, Los Angeles (UCLA) activity score, the Oxford Hip Score (OHS) and the EuroQol scores. Radiologically, all hips were assessed for migration and osteolysis, the hybrid THRs for polyethylene wear and the BHRs for a pedestal sign. The mean follow-up of the patients with a hybrid THR was 16 years and for those with a BHR, 15 years. 12 patients with a hybrid THR and 6 with a BHR had died. 2 patients with a BHR refused follow up but remain unrevised and 5 were lost to follow-up, as was 1 with a hybrid THR. The revision rate of the hybrid THRs was 28% (15 of 54) and of the BHRs 11% (6 of 54) (p = 0.029). Radiographs of a further 13 hybrid THRs demonstrated wear and osteolysis but are functioning well and are under observation. Of the unrevised BHRs 96% had radiological changes, of which approximately 17% had progressed over the previous 6 years. All hybrid THRs demonstrated linear polyethylene wear with a mean of 1.84mm (0.06 to 2.6). The BHRs recorded superior OHS (p = 0.03), UCLA (p = 0.0096), and EuroQol visual analogue scores (p = 0.03). After 15 years, patients with BHRs remained more active and had a lower rate of revision and death than those with hybrid THRs. Both groups demonstrated progressive radiological changes at long-term follow-up

Uncemented total hip arthroplasty (THA) implants have become the standard for younger patients on account of increased implant survivorship and multiple other advantages. Nevertheless, uncemented THA remains controversial in elderly patients. The evidence base for this is limited, as previous studies have compared octogenarians to a younger control group. The aim of this prospective cohort study is to evaluate the outcome of octogenarian patients undergoing uncemented THA with a control group of similarly aged patients undergoing hybrid THA with a minimum 5 years follow up. Clinical outcomes including intra and postoperative complications, blood transfusion, revision rate and mortality were recorded. Radiological analysis of pre and postoperative radiograph assessed bone quality, implant fixation and any subsequent loosening. 143 patients, (mean age 86.2 yrs.) were enrolled in the study. 76 patients underwent uncemented THA and 67 underwent hybrid THA. The uncemented cohort had fewer intraoperative and postoperative complications. The uncemented cohort also had a lower transfusion rate (p=0.002). Mean hospital stay (p=0.27) was comparable between the 2 groups. Two patients underwent revision surgery in either cohort. Our study demonstrates uncemented THA is safe for the octogenarian patient and we recommend that age should be not be a barrier of choice of implant. However intraoperative assessment of bone quality should guide surgeon to the optimum decision regarding uncemented and hybrid implant

BACKGROUND. Hybrid total hip arthroplasty (THA) commonly recognized as cementless hemi-spherical acetabular component combined with cemented femoral stem. We have done so called “reverse” hybrid THA with cemented socket and cementless stem and compared with all-cemented THAs. PATIENTS AND METHODS. We have been collecting data on total hip arthroplasty since November, 1993. Reverse hybrid hip replacements were used mainly from February, 2001. We evaluated data on 272 reverse hybrid THAs (223 patients) from this year onward until May, 2010, and compared the results with those from 283 all-cemented THAs (237 patients) between 1993 and May, 2010. Eighty percent or more of patients had diagnosed as secondary osteoarthritis of the hip joint due to dysplasia in our hospitals. Highly cross linked ultrahigh molecular polyethylene (CLP) socket was introduced in October, 1999. We used conventional (not cross linked polyethylene) socket for 82 hips (cemented group-1) operated before October, 1999 and CLP socket for 201 hips (cemented group-2) in all-cemented cases. We used the Kaplan-Meier method for estimation of prosthesis survival and relative risk of revision. The endpoint was radiological loosening or revision. Socket linear wear rates were also assessed in radiographically. Clinical assessment was performed using the Japanese Orthopedic Association (JOA) scores and Merle d'Aubigne & Postel scores. RESULTS. We have 12 hips (11 sockets and 1 stem) with radiological loosening in all cemented series and no hips in reverse hybrid series. A case with stem loosening in all cemented THAs had fractured stem without bony support due to massive osteolysis caused by heavy polyethylene wear. All of the loosening cases had conventional polyethylene socket and six of them were revised. Socket linear wear rates were calculated as 0.171 +/− 0.069, 0.030+/− 0.027, and 0.035+/− 0.026 mm per year for cemented group-1, group-2 and reverse hybrid cases, respectively. Clinical scores were significantly improved those at the time of final follow up compared with those of preoperative assessment. There were significant differences between conventional and cross linked polyethylene cases. We found no significant difference survival to that from cemented THR at 12 years (all cemented: 96.1% (95% CI: 92.7–99.1); reverse hybrid: 100%) (Figure 1). DISCUSSION AND CONCLUSION. With a follow-up of up to 12 years, reverse hybrid THAs performed well, and similarly to all-cemented THRs from the same time period. The reason for loosening was mainly bone loss and osteolysis due to polyethylene socket wear. It is no problem if the stem was installed by cemented or cementless fixation, because the rates of stem loosening were very low in the current study. The reverse hybrid method might therefore be an alternative to all-cemented THR. Longer follow-up time is needed to evaluate whether reverse hybrid hip arthroplasty has any advantages over all-cemented THA

Background. Polyethylene wear in both cemented and uncemented total hip arthroplasty (THA) lead to generation of particles with their access to the interface which has been responsible for periprosthetic osteolysis and subsequent loosening of cup and stem. Many studies have been published studying the pattern of polyethylene wear and its relation to the type of implant (cemented/ uncemented cup or ceramic/metal head) used. No study in our knowledge has strictly focused on the effect of cemented versus uncemented stem on the polyethylene wear rates. We tried to compare the polyethylene wear rates reckoned with software (Poly Ware REV 7) of ultra high molecular weight polyethylene (UHMWPE) in hybrid and uncemented THA and its effect on complications of total hip replacements. Method. We retrospectively reviewed pre-matched 56 patients in uncemented group with 112 patients in hybrid group on the basis of polyethylene wear rate, revision rates and clinical issues, with mean follow up of 9.42 and 7.25 years (yrs.) respectively. Results. Mean polyethylene wear rate in uncemented group was 0.048 milli metres per year (mm/yr.) and it was 0.082 mm/yr. in hybrid. Wear rate in hybrid group ceramic head (0.072mm/yr.) was significant when compared to wear rate ceramic head in uncemented group (0.053mm/yr.), also we found significant difference of poly wear in the metallic group as well. There was no difference in stem loosening and cup osteolysis in low wear (<.05 mm/yr.) and high wear group (>.05mm/yr.) in both uncemented and hybrid THA. Conclusion. The revision was significantly higher in uncemented group but when adjusted with the age, it is equivocal. We found significant difference in polyethylene wear rates, but no significant difference in clinical performance and revisions among the two groups of uncemented THA and hybrid THA when compared on a mid-term 8 to 10 yrs. Follow up. Keywords. Total Hip Arthroplasty; Polywear; Uncemented THA; Hybrid THA

INTRODUCTION. In gap balancing technique, we decided the femoral component rotation according to the ligament balance in flexion. Component and limb alignment are important considerations during TKA. Three-dimensional positioning of TKA implants and exact mechanical axis has an effect on implant loosening, polyethylene stresses, and gait. According to the recent report, the navigation system made it possible to achieve aligned implants more than conventional TKA. Hybrid Navigation technique which is our procedure is combination of navigation system and modified gap technique. In other words, exact mechanical axis is gained by navigation system, stable stability of knee joint is gained by modified gap technique. PURPOSE. The purpose of this study is to carry out clinical evaluation and image evaluation of the patients who underwent hybrid navigation technique TKA. METHODS. We performed TKA using the hybrid navigation technique in 100 knees from April 2012 to April 2015. We evaluated hybrid navigation TKA which we were able to follow up more than five years. 33 knees were available for follow up. We investigated the mid-term results of TKA after a mean follow up period of 5 years and 8 months. We evaluated range of motion(ROM), Japan Orthopaedic Association (JOA)score, complications, revision rate as clinical evaluations. And we evaluated radiolucent line(RLL), loosening in X-ray, implantation accuracy in computed tomography(CT) as image evaluations. Surgical technique was that the knees were exposed using a medial parapatellar approach without patella turnover, and the anterior and posterior cruciate ligaments were resected. And next osteotomy distal femur and proximal tibia using CT-free Navigation, step-wise medial soft tissue release was performed to make the rectangular extension joint gap using gap tensor space (off set balancer) at 40 pounds of distraction force. Flextion gap was made at the same distraction force, thereby we determined external rotation angle of femur osteotomy in a patella reduction position. CT of the whole leg was taken preoperation and postoperation the first postoperative week in all cases. RESULTS. In CT evaluation, coronal and sagittal alignments of femoral componet were mean 90.92° and mean flex 3.02°. These alignment of tibial componet were 90.54° and mean posterior slope 3.0°. Outliers(>3°)of coronal aligment were 6% (2 knees)in femoral componet, and 6%(2 knees) in tibial componet. In clinical evaluation, mean preoperative ROM(flex) was 105 degrees which improved 122 degrees at final follow up. Mean preoperative JOA score was 46.3 which improved 85.8 at final follow up. In image evaluation, there were no incidence of component loosening(RLL>2mm). We experienced two complications(1 deep infection and 1 intraoperative fracture), but there were no postoperative fracture and DVT/PE. The revision arte was 3%(1 knee) due to deep infection. DISCUSSION AND CONCLUSION. Mid-term postoperative results has shown a good prognosis. We will not understand that we do not observe long-term results in future, neverthless we believe that this technique should be considered as an alternative means of conducting TKA

Background. There are few studies of total knee replacements with cemented tibia and uncemented femur (hybrid). Previous studies have not shown any difference in revision rate between different fixation methods, but these studies had few hybrid prostheses. This study evaluates the results of hybrid knee replacements based on data from the Norwegian Arthroplasty Register (NAR). Patients and Methods. Primary total knee replacements without patella resurfacing, reported to the NAR during the years 1999–2009, were evaluated. Hinged-, posterior stabilized- and tumor prostheses were excluded. LCS- and Profix prostheses with conforming plus bearing were included. With the risk for revision at any cause as the primary end-point, 2945 hybrid knee replacements (HKR) were evaluated against 20838 cemented knee replacements (CKR). Kaplan-Meier survival analysis and Cox regression analysis with adjustment for age, sex and preoperative diagnosis were used. Results. Kaplan-Meier estimated survival at 8 years was 94.0% (95% CI: 93.6–94.4) in the CKR group and 97.0% (95% CI: 96.0–98.0) in the HKR group. The HKR group was made op of three brands of prosthesis, LCS, LCS-complete and Profix. Profix was the only brand with a statistically significant difference between cemented and hybrid fixation. Kaplan-Meier estimated survival at 8 years was 97.7% (95% CI: 96.7–98.7) in hybrid Profix group (HPG) and 95.5% (95% CI: 94.7–96.3) in the cemented Profix group (CPG). The adjusted Cox regression analysis showed a statistically significantly lower risk for revision in the HPG group (relative risk=0.44, 95% CI: 0.39–0.59, p<0.001). Mean operating time was 15 minutes longer in the CKR group. Conclusion. Survivorship at 8 years of the hybrid primary total knee replacements was the same or superior compared to cemented total knee replacements depending on prosthesis brand Hybrid fixation seems to be a safe alternative to cemented fixation in total knee replacement surgery

In current practice in the UK there are three main approaches to investigating suspected scaphoid fractures not seen on initial plain film x-rays. Early MRI of all cases. Review all cases in clinic at two weeks with repeat x-rays. Hybrid model. Virtual Fracture Clinic (VFC) triage to reduce those who are seen in clinic at two weeks by:. ∘. Organising early MRI for those with high-risk presentation. ∘. Discharging those with an alternative more likely diagnosis. Our unit uses the VFC model. We aimed to evaluate its efficiency, safety, clinical outcomes and economic viability. All patients attending the emergency department with either a confirmed or suspected scaphoid fracture between March and December 2020 were included (n=305). Of these 297 were referred to the VFC: 33 had a confirmed fracture on x-ray and 264 had a suspected fracture. Of the suspected fractures reviewed in VFC 14% had an MRI organised directly owing to a high-risk presentation, 79% were brought for fracture clinic review and 17% discharged with an alternative diagnosis such as osteoarthritis. Of those subsequently reviewed in fracture clinic at two weeks: 9% were treated as scaphoid fractures (based on clinical suspicion and repeat x-rays), 17% had MRI or CT imaging organised, 5% did not attend and 69% were discharged. Overall, 17% of cases initially triaged, had further imaging – 41 MRIs and 5 CTs. MRI detected: 5% scaphoid fracture, 17% other fracture, 24% bone contusion, complete ligament tear 10%, partial ligament tear 39% and normal study 10%. The results of MRI minimally affected management. 3 patients were taken out of plaster early, 1 patient was immobilized who was not previously and no patients underwent operative management. In the following 12-month period one patient re-presented with a hand or wrist issue. This approach avoided 218 MRIs, equating to £24000 and 109 hours of scanner time. VFC triage and selective use of MRI scanning is a safe, efficient and cost-effective method for the management suspected scaphoid fractures. This can be implemented in units without the resource to MRI all suspected scaphoid fractures from the emergency department

Biodegradable porous scaffolds play an important role in tissue engineering as the temporary templates for transplanted cells to guide the formation of the new organs. The most commonly used porous scaffolds are constructed from two classes of biomaterials. One class consists of synthetic biodegradable polymers such as poly (α-hydroxy acids), poly(glycolic acid), poly(lactic acid), and their copolymer of poly(DL-lactic-co-glycolic acid) (PLGA). The other class consists of naturally derived polymers such as collagen. These biomaterials have their respective advantages and drawbacks. Therefore, hybridization of these biomaterials has been expected to combine their advantages to provide excellent three-dimensional porous biomaterials for tissue engineering. Our group developed one such kind of hybrid biodegradable porous scaffolds by hybridizing synthetic poly (α-hydroxy acids) with collagen. Collagen microsponges were nested in the pores of poly (α-hydroxy acids) sponge to construct the poly (α-hydroxy acids)-collagen hybrid sponge. Observation by scanning electron microscopy (SEM) showed that microsponges of collagen with interconnected pore structures were formed in the pores of poly (α-hydroxy acids) sponge. The mechanical strength of the hybrid sponge was higher than those of either poly (α-hydroxy acids) or collagen sponges both in dry and wet states. The wettability with water was improved by hybridization with collagen, which facilitated cell seeding in the hybrid sponge. Use of the poly (α-hydroxy acids) sponge as a skeleton facilitated formation of the hybrid sponge into the desired shapes with high mechanical strength, while collagen microsponges contributed good cell interaction and hydrophilicity. One of such kind of hybrids. Additionally, our group developed a hydrostatic pressure bioreactor for chondrocyte culture. And our study showed that hydrostatic pressure (0–3 MPa) had promotional effects on the production of proteoglycan and type II collagen by cultured chondrocytes. Therefore, it would be a promising pathway for reconstructing cartilage-like tissue to culture chondrocytes in this three-dimensional hybrid sponge under physiological hydrostatic pressure

Background. Magnetic resonance imaging (MRI) algorithm identifies end stage severely degenerated disc as ‘black’, and a moderately degenerate to non-degenerated disc as ‘white’. MRI is based on signal intensity changes that identifies loss of proteoglycans, water, and general radial bulging but lacks association with microscopic features such as fissure, endplate damage, persistent inflammatory catabolism that facilitates proteoglycan loss leading to ultimate collapse of annulus with neo-innervation and vascularization, as an indicator of pain. Thus, we propose a novel machine learning based imaging tool that combines quantifiable microscopic histopathological features with macroscopic signal intensities changes for hybrid assessment of disc degeneration. Methods. 100-disc tissue were collected from patients undergoing surgeries and cadaveric controls, age range of 35–75 years. MRI Pfirrmann grades were collected in each case, and each disc specimen were processed to identify the 1) region of interest 2) analytical imaging vector 3) data assimilation, grading and scoring pattern 4) identification of machine learning algorithm 5) predictive learning parameters to form an interface between hardware and software operating system. Results. Kernel algorithm defines non-linear data in xy histogram. X,Y values are scored histological spatial variables that signifies loss of proteoglycans, blood vessels ingrowth, and occurrence of tears or fissures in the inner and outer annulus regions mapped with the dampening and graded series of signal intensity changes. Conclusion. To our knowledge this study is the first to propose a machine learning method between microscopic spatial tissue changes and macroscopic signal intensity grades in the intervertebral disc. No conflict of interest declared.  . Sources of Funding. ICMR/5/4-5/3/42/Neuro/2022-NCD-1, Dr TMA PAI SMU/ 131/ REG/ TMA PURK/ 164/2020. A part of the above study was presented as an oral paper at the International Society for the Study of Lumbar Spine (ISSLS) meeting held on 1–5. th. May 2023, Melbourne, Australia

Over the past fifteen years, computer-assisted surgery systems have been more commonly used, especially in joint arthroplasty. They allow a greater accuracy and precision in surgical procedures and thus should improve outcomes and long term results. New instruments such as guided handheld tools have been recently developed to ultimately eliminate the need for drilling/cutting or milling guides. To make sure that the handheld tool cuts and/or drills in the desired plane, it has to be servo-controlled. For this purpose, the tool joints are actuated by computer-controlled motors. A tracking system gives the tool position and orientation and a computer calculates the corrections for the motors to keep the tool in the desired plane. For this servo-control, a very fast tracking system would be necessary. It should be fast enough to follow human motion. Current optical tracking systems used for computer-assisted surgery have a bandwidth of about 10–60 Hz [3]. For servo-control, a bandwidth of about 200–300 Hz would be required to be faster than human reaction; the latency of the system should also be small, about 2–3 ms. Optical tracking systems with a higher bandwidth exist but are too expensive for applications in surgery; besides the latency – due to the complex computer vision treatment involved – is too big. We have developed a hybrid tracking system consisting of two cameras pointed at the operating field and a sensor unit which can be attached to a handheld tool. The sensor unit is made up of an inertial measuring unit (IMU) and numerous optical markers. The data from the IMU (three gyroscopes and three accelerometers placed such that their measurement axes are perpendicular to each other) and the marker images from the cameras looking at the optical markers are fed to a data fusion algorithm. This algorithm calculates the position and the orientation of any handheld tool. It can do so at the higher of the two sensor sample rates which is the IMU sample rate in our case. Our experimental setup consists of an ADIS 16355 IMU which runs at a sample rate of 250 Hz and a pair of stereo cameras which are sampled at 16.7 Hz. The data collected from these sensors are processed offline by the data fusion algorithm. To compare the results of our hybrid system to those of a purely optical tracking system, we use only the marker image data to recalculate the sensor unit's position by triangulation. The experiment we conducted was a fast motion in a horizontal direction starting from a rest position. The sensor unit position was calculated by the hybrid system and by the optical tracking system using the experimental data. The fast motion started right after the optical sample at t1 and the hybrid system detects it at once. The optical tracking system, on the other hand, only sees the motion at the next optical sample time t2. These results show that our hybrid system is able to follow a fast motion of the sensor unit whereas a purely optical tracking system is not. The proposed hybrid tracking system calculates position and orientation of any handheld tool at a high frequency of 250 Hz and thus makes it possible to servo-control the tool to keep it in the desired plane. Several similar systems fusing optical and inertial data have been described in the literature. They all use processed optical data, i.e. 3D marker positions. Our algorithm uses raw image data to considerably reduce computation time. This hybrid tracking system can be used with any handheld tool developed to substitute existing drilling, cutting or milling instruments used in orthopaedic surgery and particularly in arthroplasty. The sensor unit can be easily implemented into an existing optical tracking system. For the surgeon, the only change is an additional small inertial sensor besides the optical markers already attached to the tool. The authors would like to thank the AXA Research Fund for funding G.C. Claasen's work with a doctoral grant and Guillaume Picard for his contributions to the experimental setup

Introduction: To determine the stiffness characteristics of a new proposed hybrid fixator in comparison with more commonly used hybrid external fixators. Methods: A prospective laboratory investigation was used to evaluate the null hypothesis that there are no differences in the mechanical stiffness between the new proposed hybrid fixator and the Ace-Fischer, DePuy-ACE, Warsaw, IN; Hoffmann II, Stryker Howmedica Osteonics, Rutherford, NJ; Synthes Hybrid, Synthes USA, Paoli, PA; EBI DynaFix®, EBI, Parsippany, NJ. Identical composite tibiae, after modeling OTA 41 – A 2.3 fracture, were fixed with the above fixators. Load-deformation behavior was compared between the different configurations under identical conditions of central-compression, medial compression-bending, posterior compression-bending, posterior-medial compression-bending and torsional loading. Stiffness values were calculated from the load deformation and the torque angle curves. Results: The new proposed hybrid external fixator was stiffer than all the other fixators tested in all modes of testing, except for torsion. The Hoffman II, DePuyACE, EBI, and Synthes fixators were essentially equivalent in stiffness in all five modes of testing. Conclusions: Decreasing the distance of the side bar to the center of the bone effectively shortens the length of the half-pins, which decreases their deflection during bending, and thus increases stiffness. We think that a better stiffness of new fixator than of others is due to a shorter distance between the bone surface and points of fixation of wires and half-pins. The proposed hybrid fixator corresponds to the contemporary requirements for external fixation: possibility to control the stiffness, easy to apply, comfortable for the patient (being light and simple)