Merriam Webster - ide•al adjective \ī-′dē(−ə)l, ′ī\: exactly right for a particular purpose, situation, or person. Dictionary.com. - 1: conceived as constituting a standard of perfection or excellence; 2: regarded as perfect of its kind; 3: existing only in the imagination; not real or actual. Concepts: Tissue Preserving - anterior and posterior capsule maintained: YES; No dislocation; Minimal leg manipulation; Rapid Rehabilitation: YES; Half the average LOS at NE Baptist; Safe: YES; Fewer complications than standard approach; Transferable and Reproducible ???; Limited adoption; Optimally executed with navigation; Leg length assessment less accessible; Neck cut measured from GT; “Funny looking” impactors/reamers - different “feel”. IDEAL: For some… but not for most

Introduction. Accurate alignment of components in total knee arthroplasty (TKA) is a known factor that contributes to improvement of post-operative kinematics and survivorship of the prosthetic joint. Recently, CAOS has been introduced into TKA in effort to reduce positioning variability that may deviate from the mechanical axis. However, literature suggests that clinical outcomes following TKA with CAOS may not present a significant improvement from traditional methods of implantation. This would infer that achieving correct alignment, alone, might be insufficient for ensuring an optimal reconstruction of the joint. Therefore, this study seeks to evaluate the importance of soft-tissue balancing, through the quantification of joint kinetics collected with intraoperative sensors, with or without the combined use of CAOS. Methods. Seven centers have contributed 215 patients who have undergone primary TKA with the use of intraoperative sensors. Of the 7 surgeons contributing patients to this study, 3 utilize CAOS; 4 utilize manual techniques. Along with standard demographic and surgical data being collected as per the multicenter study protocol, soft-tissue release techniques and medial-lateral intercompartmental loads—as indicated by the intraoperative sensors—were also captured pre- and post-release. “Optimal” balance was defined as a medial-lateral load difference of ≤ 15 lbs. A chi-squared analysis was performed to determine if the percentage of soft-tissue release was significantly different between the two groups: patients with CAOS, and patients without CAOS. Results. Of the 215 patients (35% with CAOS, 65% without CAOS) who have received TKA, using intraoperative sensors to assess mediolateral balance, 92.6% underwent soft-tissue release. Stratifying this data by surgical technique: 89% of the patients with CAOS, and 94% of patients without CAOS, were released. A chi-squared analysis—with 3 degrees of freedom; and 99% confidence—was executed to determine if the 5% difference between the two groups was significant. The analysis showed that there was no significant difference between the two groups, thus we can conclude that soft-tissue release is as equally necessary in the CAOS TKA group, as it is in the traditional TKA group. Discussion. It is widely accepted that correct alignment of TKA components contributes to improved kinematic function of the affected joint. Recently, technology has been developed to digitally guide surgeons through bony cuts, thereby decreasing the incidence of deviation from the mechanical axis. However, alignment may not be the foremost contributing factor in ensuring an optimal joint state. In this evaluation, 92.6% of the cohort required some degree of releasing of ligamentous structures surrounding the knee joint, regardless of intraoperative technique used. A chi-squared analysis of the data supports the claim that soft-tissue release is used in nearly all cases, irrespective of the use of CAOS (p < 0.001). This suggests that soft-tissue release is necessary in nearly all cases, even after appropriate alignment has been digitally verified. The data strongly supports the idea that obtaining an optimally functioning joint is multifactorial, and that alignment may play a more minor role in achieving ideal joint reconstruction than previously assumed, being superseded by the necessity to achieve soft-tissue balance

Economic data, clinical outcome studies, and anatomical studies continue to support the Superior Hip Approach as a preferred approach for improved safety, maximal tissue preservation, rapid recovery, and minimised cost.

Clinical studies show exceedingly low rates of all major complications including femur fracture, dislocation, and nerve injury.

Economic data from Q1 2013 to Q2 2016 demonstrate that CMS-insured patients treated by the Superior Hip Approach have the lowest cost of all patients treated in Massachusetts by an average of more than $7,000 over 90 days. The data show that the patients treated by the Superior Hip Approach have lower cost than any other surgical technique.

Matched-pair bioskills dissections demonstrate far better preservation of the hip joint capsule and short external rotators than the anterior approach.

Design principles include: Preservation of the abductors; Preservation of the posterior capsule and short external rotators; Preparation of the femur in situ prior to femoral neck osteotomy; Excision of the femoral head, thereby avoiding surgical dislocation of the hip; In-line access to the femoral shaft axis; Ability to perform a trial reduction; Independence from intra-operative imaging; Independence from a traction table; Applicable to at least 99% of THA procedures.

Several design principles were considered paramount when the surgical technique of performing total hip arthroplasty through an incision in the superior capsule without dislocation of the hip joint was developed. These design principles include: Preservation of the abductors; Preservation of the posterior capsule and short external rotators; Preparation of the femur in situ without dislocation of the hip; In-line access to the femoral shaft axis; Ability to perform a trial reduction; Independence from intraoperative imaging; Independence from a traction table; Applicable to at least 99% of THA procedures

Personal experience with more than 1950 THA using the superior capsulotomy technique over a 12-year period has demonstrated several observations: Dislocation rate of 0.15% (3 in 1950); Acute deep infection rate of 0% (0 in 1950); Universal applicability: used in 99.7% of primary THA; Lateral femoral cutaneous nerve palsy incidence: 0/1950; Femoral nerve palsy incidence: 0/1950; Transient peroneal palsy incidence: 2/1950; Length of stay (since 2010): 1.55 days; Discharge to home: 98%; 90-day cost (2/13 to 2/14) compared to other exposures in CMS patients in the same institution: $24,200 vs $30,100; Readmission costs (CMS 2/13 to 2/14) at 90 days: $0.

Conclusion: Performing total hip arthroplasty without dislocation and with preservation of the abductors, posterior capsule and short external rotations has proven to have a low dislocation rate, a low infection rate, and wide applicability. CMS 12-month expenditure data documenting ZERO dollars spent on readmission for any reason within 90 days of surgery demonstrates the potential for simultaneously improving incomes and reducing cost, with particular benefit within the CMS BPCI and private bundled payment programs.

Soft tissue sarcomas (STS) have not demonstrated favourable clinical responses to emerging immunotherapies such as checkpoint inhibitors. Studies in carcinomas and melanoma have demonstrated that tumours lacking T-cell infiltrates are associated with poor responses to immunotherapies. It is postulated that STS lack tumour asscoiated lymphocytes which renders these tumours insensitive to checkpoint inhibitors. Our objective was to develop a novel syngeneic mouse model of STS and characterize the immune phenotype of these tumours. Additionally, we sought to evaluate the therapeutic responses of these sarcomas to checkpoint inhibitors and a Type I interferon agonist.

K-ras mutagenesis and p53 deletion was induced using a Lenti-Cre-recombinase injection into the hindlimb of 3 week old C57BL/6 mice. Tumours were harvested and characterized using standard histopathology techniques and whole trascriptome sequencing (RNAseq). Full body necrospy and histopathology was performed to identify metastases. Flow cytometry and immunohistochemistry was used to evaluate tumour immune phenotypes. Tumours were implanted into syngeneic C57BL/6 mice and the therapeutic responses to anti-CTLA4, anti-PD1 and DMXAA (Type I interferon agonist) were performed. Tumour responses were evaluated using bioluminescent imaging and caliper measurements.

Soft tissue sarcomas developed in mice within 2–3 months of Lenti-Cre injection with 90% penetrance. Histologic analyses of tumours was consistent with a high-grade myogenic sarcoma characterized by smooth muscle actin, Desmin and Myogenin D positive immunostaining. Using crossplatform normalization protocols, geneexpression signatures of the mouse tumours most closely correlated with human undifferentiated pleomorphic sarcoma (UPS). Collectively, gene expression signatures of this murine sarcoma correlated with all muscle-derived human sarcomas (ERMS, ARMS, Synovial sarcoma, UPS). No lung or other visceral metastases were observed in all mice who developed spontaneous tumours. Immune phenotyping demonstrated a paucity of tumour-infiltrating lymphocytes (TILs, (TAMs). 50% of identified TILs in these murine sarcomas expressed PD-1, yet tumours were not responsive to anti-PD1 therapy or anti-CTLA4 therapy. A single intra tumoural (i.t.) injection of the Type I interferon agonist, DMXAA resulted in 80–90% tumour necrosis 72 hrs post-injection, decreased tumour viability up to 2 weeks post-injection and a marked infiltration of CD8+ T-cells and anitgen presenting dendritic cells and macrophages. Additional longitudinal experiments demonstrate a sustained and progressive anti-tumour effect in 83% (5/6) mice up to 6weeks following a single i.t. injection of DMXAA. All control treated mice (6/6) reached humane endpoint within 14 days. At 3 months post-DMXAA treatment, 4/6 mice were free of disease. We re-injected UPS tumours into these mice and tumours did not grow, suggesting abscopal effects after DMXAA treatment of primary tumours.

We have characterized a new orthotopic and syngeneic mouse model of a myogenic soft tissue sarcoma. Like most human STS sub-types, these tumours have an immune inert tumour microenvironment and are not sensitive to checkpoint inhibitors. This model, syngeneic to C56BL/6 mice will enable future opportunities to investigate how various branches of the immune system can be targetted or manipulated to unearth new immunotherapeutic strategies for sarcoma. Using this model we have demonstrated that a single, intra-tumoural injection of a Type I interferon agonist can result in anti-tumour effects, recruit cytotoxic lymphocytes and antigen presenting cells with into the the tumour microenvironment. Abscopal tumour rejection after DMXAA treatement suggest adaptive T-cell responses against UPS are active in this model. Future work is needed to determine if upregulation of Type I inferferon pathways can be used as a therapeutic strategy for sarcoma or as a sensitization strategy for checkpoint inhibitors.

Introduction

The posterior condylar axis of the distal femur is the common reference used to describe femoral anteversion. In the context of Total Hip Arthroplasty (THA), this reference can be used to define the native femoral anteversion, as well as the anteversion of the stem. However, these measurements are fixed to a femoral reference. The authors propose that the functional position of the proximal femur must be considered, as well as the functional relationship between stem and cup (combined anteversion) when considering the clinical implications of stem anteversion. This study investigates the post-operative differences between anatomically-referenced and functionally-referenced stem and combined anteversion in the supine and standing positions.

Introduction

The goal of tibial tray placement in total knee arthroplasty (TKA) is to maximize tibial surface coverage while maintaining proper rotation. Maximizing tibial surface coverage without component overhang reduces the risk of tibial subsidence. Proper tibial rotation avoids excess risk of patellar maltracking, knee instability, inappropriate tibial loading, and ligament imbalance. Different tibial tray designs offer varying potential in optimizing the relationship between tibial surface coverage and rotation. Patient specific instrumentation (PSI) generates customized guides from an MRI- or CT-based preoperative plan for use in TKA. The purpose of the present study was to utilize MRI information, obtained as part of the PSI planning process, to determine, for anatomic, symmetric, and asymmetric tibial tray designs, (1) which tibial tray design achieves maximum coverage, (2) the impact of maximizing coverage on rotation, and (3) the impact of establishing neutral rotation on coverage.

The goal of tibial tray placement in total knee arthroplasty (TKA) is to maximise tibial surface coverage while maintaining proper rotation. Maximising tibial surface coverage without component overhang reduces the risk of tibial subsidence. Proper tibial rotation avoids excess risk of patellar maltracking, knee instability, inappropriate tibial loading, and ligament imbalance. Different tibial tray designs offer varying potential in optimising the relationship between tibial surface coverage and rotation. Patient specific instrumentation (PSI) generates customised guides from an MRI- or CT-based preoperative plan for use in TKA. The purpose of the present study was to utilise MRI information, obtained as part of the PSI planning process, to determine, for anatomic, symmetric, and asymmetric tibial tray designs, (1) which tibial tray design achieves maximum coverage, (2) the impact of maximising coverage on rotation, and (3) the impact of establishing neutral rotation on coverage.

MR images for 100 consecutive patients were uploaded into Materialise™ PSI software that was used to evaluate characteristics of tibial component placement. Tibial component rotation and surface coverage was analysed using the preoperative planning software. Anatomic (Persona™), symmetric (NexGen™), and asymmetric (Natural-Knee II™) designs from a single manufacturer (Zimmer™) were evaluated to assess the relationship of tibial coverage and tibial rotation. Tibial surface coverage, defined as the proportion of tibial surface area covered by a given implant, was measured using Adobe Photoshop™ software. Rotation was calculated with respect to the tibial AP axis, which was defined as the line connecting the medial third of the tibial tuberosity and the PCL insertion.

When tibial surface coverage was maximised, the anatomic tray compared to the symmetric/asymmetric trays showed significantly higher surface coverage (82.1% vs 80.4/80.1%; p<0.01), significantly less deviation from the AP axis (0.3° vs 3.0/2.4°; p<0.01), and a significantly higher proportion of cases within 5° of the AP axis (97% vs 73/77%). When constraining rotation to the AP axis, the anatomic tray showed significantly higher surface coverage compared to the symmetric/asymmetric trays (80.8% vs 76.3/75.8%; p<0.01). No significant differences were found between symmetric and asymmetric trays.

We found that the anatomic tibial tray resulted in significantly higher tibial coverage with significantly less deviation from the AP axis compared to the symmetric and asymmetric trays. When rotation was constrained to the AP axis, the anatomic tray resulted in significantly higher tibial coverage than the symmetric and asymmetric trays. Tibial rotation is recognised as an important factor in the success of a total knee replacement. Maximising coverage with the least compromise in rotation is the goal for tibial tray design. In this study, the anatomic tibia seemed to optimise the relationship between tibial surface coverage and rotation. This study additionally illustrates the way by which advanced preoperative planning tools (ie. MRI/computer reconstructions) allow us to obtain valuable information with regard to implant design.

Despite the vast quantities of published artificial intelligence (AI) algorithms that target trauma and orthopaedic applications, very few progress to inform clinical practice. One key reason for this is the lack of a clear pathway from development to deployment. In order to assist with this process, we have developed the Clinical Practice Integration of Artificial Intelligence (CPI-AI) framework – a five-stage approach to the clinical practice adoption of AI in the setting of trauma and orthopaedics, based on the IDEAL principles (. https://www.ideal-collaboration.net/. ). Adherence to the framework would provide a robust evidence-based mechanism for developing trust in AI applications, where the underlying algorithms are unlikely to be fully understood by clinical teams. Cite this article: Bone Joint Res 2024;13(9):507–512

Staphylococcus aureus osteo-articular infections (OAI) are frequently accompanied by blood stream infections (BSI) diagnosed by positive blood culture (BC). Microbiological protocols in adults advise prolonged intravenous antibiotics and repeat BC 48-hourly in the presence of a BSI, however evidence to support the systematic employment of these guidelines in paediatric patients is lacking. We aimed to determine whether there was an increased incidence of orthopaedic and systemic complications in patients with s aureus BSI, and whether a shorter duration of intravenous antibiotics was associated with the development of complications. Following ethical approval, the departmental surgical database was searched for patients that underwent surgery for acute OAI over a 5-year period. Patients with no sample taken for BC were excluded, as were those with other or no organisms identified from any site. Demographic and clinical data were captured, including duration of IV antibiotics and development of complications. Statistical significance was set at p<0.05. Following exclusions, 44 patients with a median age of 85 months remained to be analysed. Thirty patients (68%) had a positive BC. A positive BC was associated with a higher rate of systemic complications (p=0.026) but not orthopaedic complications (p=0.159). Patients who had developed any complication had a significantly longer duration of IV antibiotic treatment compared to those without complications (p<0.001). The presenting CRP levels were significantly higher in patients that developed complications (p=0.004). Patients with staphylococcal BSI in association with an OAI are at increased risk of developing systemic complications. In our cohort, a shorter duration of antibiotic use was not associated with the development of complications, which does not support the systematic use of long courses of IV antibiotics in s aureus BSI. Further research will be required to determine the ideal protocol for these patients

Surgical site infections (SSIs) after spinal fusion surgery increase healthcare costs, morbidity and mortality. Routine measures of obesity fail to consider site specific fat distribution. We aimed to assess the association between the spine adipose index and deep surgical site infection and determine a threshold value for spine adipose index that can assist in preoperative risk stratification in patients undergoing posterior instrumented lumbar fusion (PILF). A multicentre retrospective case-control study was completed. We reviewed patients who underwent PILF from January 1, 2010 to December 31, 2018. All patients developing a deep primary incisional or organ-space SSI within 90 days of surgery as per US Centre for Disease Control and Prevention criteria were identified. We gathered potential pre-operative and intra-operative deep infection risk factors for each patient. Spine adipose index was measured on pre-operative mid-sagittal cuts of T2 weighted MRI scans. Each measurement was repeated twice by three authors in a blinded fashion, with each series of measurement separated by a period of at least six weeks. Forty-two patients were included in final analysis, with twenty-one cases and twenty-one matched controls. The spine adipose index was significantly greater in patients developing deep SSI (p =0.029), and this relationship was maintained after adjusting for confounders (p=0.046). Risk of developing deep SSI following PILF surgery was increased 2.0-fold when the spine adipose index was ≥0.51. The spine adipose index had excellent (ICC >0.9; p <0.001) inter- and intra-observer reliabilities. The spine adipose index is a novel radiographic measure and an independent risk factor for developing deep SSI, with 0.51 being the ideal threshold value for pre-operative risk stratification in patients undergoing PILF surgery

Abstract. Background. Multiple devices can stabilise the MTP joint for arthrodesis. The ideal implant should be easy to use, provide reproducible and high quality results, and ideally enable early rehabilitation to enable faster return to function, whilst lessening soft tissue irritation. We prospectively evaluated the combination of the IO-Fix (Extremity Medical, NJ, USA) device which consists of an intra-osseous post and lag screw that offers these features with full bearing of weight after surgery. Methods. 67 feet in 65 patients were treated over 31 months. After excluding patients lost to follow-up, undergoing revision arthrodesis, or concomitant first ray procedures, there were 54 feet in 52 patients available with a minimum 12 month follow-up with clinical and radiographic outcomes. All patients were treated using a similar operative technique with immediate bearing of weight in a rigid soled shoe. Results. The mean MOXFQ score improved from 46.4 (range 18 – 64) before surgery to 30.2 (range 0 – 54) at 6 months after surgery (p=0.02), and 18.4 (range 0 – 36) (p< 0.001) at latest follow-up. Arthrodesis across the MTP joint was achieved in 52 feet (96%), at a mean of 61 days (range 39–201). Non-union was observed in two feet; superficial wound infections in two feet; and metalwork impingement in three feet. Conclusions. In the largest reported series to date, the IO-Fix device achieved a union rate of 96% across the MTP joint when coupled with immediate bearing of weight. Significant improvements were seen in patient reported outcomes with low complication rates

Aim. Diagnosing low-grade periprosthetic joint infections (PJI) can be very challenging due to low-virulent microorganisms capable of forming biofilm. Clinical signs can be subtle and may be similar to those of aseptic failure. To minimize morbidity and mortality and to preserve quality of life, accurate diagnosis is essential. The aim of this study was to assess the performance of various diagnostic tests in diagnosing low-grade PJI. Methods. Patients undergoing revision surgery after total hip and knee arthroplasty were included in this retrospective cohort study. A standardized diagnostic workup was performed using the components of the 2021 European Bone and Joint Infection Society (EBJIS) definition of PJI. For statistical analyses, the respective test was excluded from the infection definition to eliminate incorporation bias. Receiver-operating-characteristic curves were used to calculate the diagnostic performance of each test, and their area-under-the-curves (AUC) were compared using the z-test. Results. 422 patients undergoing revision surgery after total hip and knee arthroplasty were included in this study. 208 cases (49.3%) were diagnosed as septic. Of those, 60 infections (28.8%) were defined as low-grade PJI (symptoms >4 weeks and caused by low-virulent microorganisms (e. g. coagulase-negative staphylococci, Cutibacterium spp., enterococci and Actinomyces)). Performances of the different test methods are listed in Table 1. Synovial fluid (SF) - WBC (white blood cell count) >3000G/L (0.902), SF - %PMN (percentage of polymorphonuclear neutrophils) > 65% (0.959), histology (0.948), and frozen section (0.925) showed the best AUCs. Conclusion. The confirmatory criteria according to the EBJIS definition showed almost ideal performances in ruling-in PJI (>99% specificity). Histology and synovial fluid cell count (SF-WBC and SF-%PMN) showed excellent accuracies for diagnosing low-grade PJI. However, a reduced immune reaction in these cases may necessitate lower cut-off values. Intraoperative frozen section may be valuable in cases with inconclusive preoperative diagnosis. For any tables or figures, please contact the authors directly

Introduction. In my paediatric Orthopaedic practice I use Kirchner wires for the fixation of the TSF on bone. I noted a significant percentage of wire loosening during the post-operative period. The aim of this project was to establish the effectiveness of the wire clamping mechanism and find ways to reduce the incidence of wire loosening when using the TSF. Materials and Methods. In the first instance wire slippage was measured intra-operatively after the tensioner was removed using an intra-operative professional camera. Following this study mechanical tests were performed in the lab measuring the pull out properties of Kirchner wires using different bolts and different torque levels in order to tighten the wire on the fixator. Results. Our clinical study confirmed wire slippage intra-operatively immediately after the tensioner was removed. Wire slippage after the tensioner was removed was found to vary from 0.01 mm to 0.51 mm (mean 0.19 mm). Our mechanical tests showed that the ideal torque for tightening the wire on the frame using a bolt was around 15 N.m. A comparison between cannulated and slotted bolts suggested that cannulated bolts are more effective as a clamping mechanism. A comparison between aluminium made Taylor Spatial frame rings and stainless steel made Ilizarov rings suggested that the Taylor Spatial frame rings are more effective as part of a clamping mechanism. Conclusions. It is important that clinicians routinely measure the torque they use to clamp wires on circular external fixators. Clinicians and manufacturers are informed that the type of bolt used is important in maintaining wire tension. Manufacturers should design the ideal bolt which effectively grips the wire without the risk of fracture. The Ilizarov frame clamping mechanism can be effectively used with the Taylor Spatial frame

Component alignment and soft tissue constraints are key factors affecting function and implant survival after total knee replacement (TKR). Knee kinematics contribute to knee function whilst soft tissue constraints and component alignment impact polyethylene wear. This study experimentally investigated the effect of soft tissue constraints and component alignment on the kinematics and wear of a TKR. A six station electromechanical ProSim knee simulator was used with the ISO 14243-1:2009 standard force control inputs; axial force, flexion-extension (FE), tibial rotation (TR) torque and anterior-posterior (AP) force. This allowed the kinematics to vary with the test conditions. The soft tissue constraints were simulated using virtual springs. DePuy Sigma XLK fixed bearing TKRs were tested in 25% bovine serum (in 0.04% sodium azide) lubricant. The average output kinematics across 6 stations were found for each test and the peak values compared. The wear rates were calculated over 2 million cycles (MC), the serum was changed every 350,000 cycles and the tibial inserts weighed after every MC. A one way ANOVA and post hoc Tukey's test was used to compare the kinematics and wear with significance taken at p<0.05. The kinematics and wear rates for three soft tissue conditions were established under ideal alignment (Table 1). The ISO standard springs for a cruciate substituting (CS) and a cruciate retaining (CR) prosthesis were used to represent a knee with a resected ACL and PCL and a knee with a resected ACL respectively. The third spring condition was based on clinical data to represent a “stiff” knee. Three other alignment conditions were then assessed using “stiff” knee springs; 4° varus, 14° rotational mismatch and 10° posterior tibial slope. These alignments were chosen to represent the range found in clinical data. Under ideal alignment the “stiff” knee springs had significantly lower peak AP and TR displacements (0.9mm, 2mm, 2mm and 3.6°, 7.1°, 7.8° for the “stiff”, CR and CS springs respectively) than the other springs (p<0.01). The “stiff” knee spring had a significantly lower wear rate than the CR spring; 1.58 ±1.20mm³/MC compared to 4.71±1.29 mm³/MC (p<0.01). The varus and rotated components had significantly larger peak AP displacements of 2.56mm and 2.42mm respectively, than the ideal and tibial slope fixtures (1.97mm and 0.92mm respectively) (p<0.01). The rotated components had significantly higher internal rotation of 12.2° compared to 4.4°, 3.7° and 3.5° for the tibial slope, varus and ideal components respectively (p<0.01). The ideal and varus components had significantly lower wear than the tibial slope and rotated components (1.58±1.20mm³/MC and 0.15±0.83mm³/MC compared to 8.24±7.72mm³/MC and 5.19±1.12mm³/MC respectively) (p<0.01). This may be due to increased AP and TR displacements with the rotated components and the increased anterior AP displacement with the tibial slope components, resulting in wear on the posterior edge of the tibial insert. Soft tissue constraints and component alignment had a significant effect on the kinematics and wear. Experimental simulation should test a variety of soft tissue and alignment conditions to reflect the range observed clinically and determine causes for early failure. For any figures or tables, please contact the authors directly

Aim. Identifying the optimal agent for irrigation for periprosthetic joint infection remains challenging as there is limited data. The ideal solution should have minimal cytotoxicity while maintaining bactericidal activity. We developed a novel activated-zinc solution containing zinc-chloride (ZnCl. 2. ) and sodium-chlorite (NaClO. 2. ). The purpose of this study was 1.) to investigate the antimicrobial efficacy of 2 concentrations (“CZ1”, “CZ2”) against Staphylococcus aureus and Pseudomonas aeruginosa and 2.) to evaluate untoward effects of the solution on local wound tissue 24 hours after solution exposure in pig wound models. Method. The study was conducted and reported in accordance to ARRIVE guidelines. We created twenty-four 1.5cm wounds on the back of a Yorkshire-cross pig. Wounds were inoculated with standardized Pseudomonas and S. aureus. 8 wounds were designated as controls (inoculum without treatment), 8 treated with CZ1, and 8 with CZ2. Punch biopsies were taken 1 hour after treatment and bacteria quantified. Wound necrosis/neutrophil infiltrate was measured 24-hours post-exposure. Results. After 1-hour, the control, CZ1 and CZ2 wounds had total bacteria of 5.7, 2.8 and 3.5 logCFU/g, respectively (p=0.017). The control, CZ1 and CZ2 wounds had S. aureus of 5.3, 2.3 and 1.6 logCFU/g, respectively (p=0.009). The control, CZ1 and CZ2 wounds had Pseudomonas of 5.5, 0.3 and 0.0 logCFU/g, respectively (p=0.000). After 24 hours of exposure to CZ1 and CZ2, there was no statistically significant increased necrosis (p=0.12, p=0.31, respectively). CZ1 had increased, moderate neutrophil infiltrate (p=0.04) when compared to controls, however CZ2 was not significant (p=0.12). Conclusions. Our novel solution demonstrated 99.5–99.9% reduction in total bacteria, 99.9–99.98 % reduction in S. aureus, and 100% eradication of Pseudomonas 1-hour after exposure, without significantly increased necrosis and no-to-minimally-increased neutrophil infiltrate. This novel solution may provide another significant tool in the arsenal to treat and/or prevent PJI and other wound infections

Aims. Accurate positioning of the acetabular component is essential for achieving the best outcome in total hip arthroplasty (THA). However, the acetabular shape and anatomy in severe hip dysplasia (Crowe type IV hips) is different from that of arthritic hips. Positioning the acetabular component in the acetabulum of Crowe IV hips may be surgically challenging, and the usual surgical landmarks may be absent or difficult to identify. We analyzed the acetabular morphology of Crowe type IV hips using CT data to identify a landmark for the ideal placement of the centre of the acetabular component as assessed by morphometric geometrical analysis and its reliability. Patients and Methods. A total of 52 Crowe IV and 50 normal hips undergoing total hip arthroplasty were retrospectively identified. In this CT-based simulation study, the acetabular component was positioned at the true acetabulum with a radiographic inclination of 40° and anteversion of 20° (Figure 1). Acetabular shape and the position of the centre of the acetabular component were analyzed by morphometric geometrical analysis using the generalized Procrustes analysis (Figure 2). To describe major trends in shape variations within the sample, we performed a principal component analysis of partial warp variables (Figure 3). Results. The plot of the landmarks showed that the centre of the acetabular component of normal hips was positioned around the centre of the acetabulum and superior and slightly posterior on the acetabular fossa (Figure 3). The acetabular shapes of Crowe IV hips were distinctively triangular; the ideal position of the centre of the acetabular component was superior on the posterior bony wall (Figure 3). The first and second relative warps explained 34.2% and 18.4% of the variance, respectively, compared with that of 28.6% and 18.0% in normal hips. We defined the landmark as one-third the distance from top on the posterior bony wall in Crowe IV hips. The average distance from the centre of the acetabular component was 5.6 mm. There were 24 hips (50%) for which the distance from 1/3 pbw was within 5 mm, and 43 hips (89.6%) for which the distance was within 10 mm. Conclusions. Morphometric geometrical analysis showed that the acetabulum shape of Crowe type IV hips was distinctively triangular; the centre of the acetabular component was not positioned at the centre of the acetabulum, but rather superior on the posterior bony wall. The point one-third from the top on the posterior bony wall was a useful landmark for surgeons to set the acetabular component in the precise position in Crowe IV hips. This avoids the risk of using a smaller acetabular component and destruction of the anterior wall. For any figures or tables, please contact the authors directly

Introduction. Acetabular dysplasia, also known as developmental dysplasia of the hip, has been shown to contribute to the onset of osteoarthritis. Surgical correction involves repositioning the acetabulum in order to improve coverage of the femoral head. However, ideal placement of the acetabular fragment can often be difficult due to inadequate visualization. Therefore, there has been an increased need for pre-operative planning and navigation modalities for this procedure. Methods. PubMed and EBSCO Host databases were queried using keywords (preoperative, pre-op, preop, before surgery, planning, plan, operation, surgery, surgical, acetabular dysplasia, developmental dysplasia of the hip, and Hip Dislocation, Congenital [Mesh]) from 1974 to March 2019. The search generated 411 results. We included all case-series, English, full-text manuscripts pertaining to pre-operative planning for congenital acetabular dysplasia. Exclusion criteria included: total hip arthroplasty (THA) planning, patient population mean age over 35, and double and single case studies. Results. A total of 12 manuscripts met our criteria for a total of 186 hips. Preoperative planning modalities described were: Amira (Thermo Fischer Scientific; Waltham, MA, USA) − 12.9%, OrthoMap (Stryker Orthopaedics; Mahwah, NJ, USA) − 36.5%, Amira + Biomechanical Guidance System (Johns Hopkins University) − 5.9%, Mills et al. method − 16.1%, Klaue et al. method − 16.1%, Armand et al. method − 6.5%, Tsumura et al. method − 3.8%, and Morrita et al. method − 2.2%. Virtual implementation of the Amira software yielded increases in femoral head coverage (p<0.05) and a significant decrease in lateral center edge angle (LCEA) (p<0.05). A significant decrease in post-surgical complications (0.0% navigated group vs. 8.7% non-navigated group, p<0.01) was found with usage of OrthoMap related planning. Conclusion. There was a notable lack of prospective studies demonstrating the efficacy of these modalities, with decreased post-surgical complications being the only added benefit of their use. Additionally, small sample sizes and lack of commercial availability for many of these programs further diminishes their applicability. Future studies are needed to compare computer assisted planning with traditional radiographic assessment of ideal osteotomy orientation. Furthermore, these programs must be readily accessible rather than be solely available to the researchers who wrote the program. For any figures or tables, please contact authors directly

Introduction. There is widespread variation in the management of rare orthopaedic disease, in a large part owing to uncertainty. No individual surgeon or hospital is typically equipped to amass sufficient numbers of cases to draw robust conclusions from the information available to them. The programme of research will establish the British Orthopaedic Surgery Surveillance (BOSS) Study; a nationwide reporting structure for rare disease in orthopaedic surgery. Methods. The BOSS Study is a series of nationwide observational cohort studies of pre-specified orthopaedic disease. All relevant hospitals treating the disease are invited to contribute anonymised case details. Data will be collected digitally through REDCap, with an additional bespoke software solution used to regularly confirm case ascertainment, prompt follow-up reminders and identify potential missing cases from external sources of information (i.e. national administrative data). With their consent, patients will be invited to enrich the data collected by supplementing anonymised case data with patient reported outcomes. The study will primarily seek to calculate the incidence of the rare diseases under investigation, with 95% confidence intervals. Descriptive statistics will be used to describe the case mix, treatment variations and outcomes. Inferential statistical analysis may be used to analyze associations between presentation factors and outcomes. Types of analyses will be contingent on the disease under investigation. Discussion. This study builds upon other national rare disease supporting structures, particularly those in obstetrics and paediatric surgery. It is particularly focused on addressing the evidence base for quality and safety of surgery, and the design is influenced by the specifications of the IDEAL collaboration for the development of surgical research

Background. Achieving good ligament balance in total knee arthroplasty (TKA) is essential to prevent early failure and revision surgery. Poor balance and instability are well-defined, however, an ideal ligament balance target across all patients is not well-understood. In this study we investigate the achieved ligament balance using an imageless, intra-operative dynamic balancing tool and its relation to patient reported outcomes. Methods. A prospective, multi-surgeon, multi-center study investigated the use of a dynamic ligament-balancing tool in combination with a robotic-assisted navigation platform using the APEX knee (OMNI-Corin, Raynham MA). After all resections, the femoral trial and a computer-controlled tensioning device in place of the tibial tray was inserted into the knee joint. The difference in medial and lateral (ML) gaps when balancing the knee under constant load at extension (10°), mid-flexion (30°) and flexion (90°) was captured. Patients completed the KOOS questionnaire at 3 months ± 2 weeks post-surgery and considered the past 7 days as a timeframe for responses. Pearson's correlation was used to determine linear correlations between factors and ANOVA tests were used to determine differences in categorical data. Results. Thirty patients have currently completed 3 months KOOS questionnaires for analysis (age: 68±9.3yrs, Male: 43%). Strong correlations were found between the difference in ML gap for KOOS symptoms and pain in extension (r=−0.54, p=0.002, r=−0.50, p=0.005, respectively) and mid flexion (r=−0.52, p=0.003, r=−0.48, p=0.007, respectively), but not in full flexion (r=−0.13, p=0.5, r=−0.23, p=0.22, respectively). A threshold of 1.5 mm difference in joint gap under constant load was used to distinguish between balanced and more lax knees medially or laterally. Worse KOOS symptoms were found in patients with tighter lateral laxity in extension and mid flexion (△=15 points, p=0.03, △=21 points, p=0.0002, respectively) compared to the rest of the cohort, see Figure 1. Similarly, worse KOOS pain was found for tight lateral laxity in mid-flexion (△=14 points, p=0.02). No significant differences were found in full flexion or for patients with a tight medial side at any flexion angle. Stronger differences in extension and mid flexion may reflect the type of activities and range of motion most commonly encountered as a TKA patient. A younger population engaging higher demand activities may be more sensitive to coronal soft tissue balance in full flexion. Conclusion. Improved patient outcomes were found to correlate with a neutrally-balanced or tighter medial soft tissue profile compared to tighter lateral structures. These results reflect the behaviour of the native knee. The cohort investigated here is small and data collection is ongoing. Further data will be needed to determine if these results can be generalized and to investigate the potential of patient specificity in ideal ligament balancing. For any figures or tables, please contact authors directly