Removal of bullets retained within joints is indicated to prevent mechanical blockade, 3rd body wear and resultant arthritis, plus lead arthropathy and systemic lead poisoning. The literature is sparse on this subject, with mostly sporadic case reports utilizing hip arthroscopy. We report on the largest series of removal of bullets from the hip joints using open surgical. We reviewed prospectively collected data of patients who presented to a single institution with civilian gunshot injuries that breached the hip joint between 01 January 2009 and 31 December 2022. We included all cases where the bullet was retained within the hip joint area. Exclusion criteria: cases where the hip joint was not breached, bullets were not retained around the hip area or cases with isolated acetabulum involvement. One hundred and eighteen (118) patients were identified. One patient was excluded as the bullet embedded in the femur neck was sustained 10 years earlier. Of the remaining 117 patients, 70 had retained bullets around the hip joint. In 44 patients we undertook bullet removal using the followingsurgical hip dislocation (n = 18), hip arthrotomy (n = 18), removal at site of fracture fixation/replacement (n = 2), posterior wall osteotomy (n = 1), direct removal without capsulotomy (tractotomy) (n = 5). In 26 patients we did not remove bullets for the following reasons: final location was extra-capsular embedded in the soft tissues (n=17), clinical decision to not remove (n=4), patients’ clinical condition did not allow for further surgery (n= 4) and patient refusal (n=1). No patients underwent hip arthroscopy. With adequate pre-operative imaging and surgical planning, safe surgical removal of retained bullets in the hip joint can be achieved without the use of hip arthroscopy; using the traditional open surgical approaches of arthrotomy, tractotomy and surgical hip dislocation

Introduction. The education of residents in the proper placement of pedicle screws is key to the safety of the surgery. The more experienced the surgeon, the more accurately the pedicle screws tend to be placed. A physical bone model, with properties and tactile feel similar to human bone, was developed with the intention of using the bone model to train residents in pedicle screw placement. The purpose of this study was to test whether the model improves the performance of orthopaedic residents when cannulating spinal pedicles, as judged by the number of breaches, and to gain feedback from the residents on their experiences. Materials and Methods. Six orthopaedic residents were recruited, with ethics approval. Prior to testing, the residents were given an instructional video describing the correct cannulation of a lumbar vertebra. The residents were each provided with 12 bones mounted in holders: 3 for initial skills assessment, 6 for free practice, and 3 for final skills assessment. In the pre- and post-practice sets, the 3 bone models had different properties: weak, normal and strong. The residents were asked to complete both pre and post-testing questionnaires. The number of breaches was counted in initial and final bone testing. The forces for each bone model were compared using an ANOVA; these were followed by post-hoc t-tests if significant (p<0.05). Results. All but one of the residents improved the number of breaches with practice, and the one that did not improve did not make the same breaches twice. The total number of breaches in the final testing (14) was lower than in the initial testing (31). The entry points chosen by the residents were all deemed appropriate as per the video instruction. The resident with the most experience had the least number of breaches; the resident with the least amount of experience had the most breaches. Discussion. The reduction of the number of breaches between the initial and final testing indicates that the residents did learn. Overall the response from the residents was positive; they all indicated they would like to have the simulator as part of their training; most even indicated an interest to use them outside of training hours. Almost all indicated that the bones felt more realistic than those currently available (if they were aware of them). Positively, the more surgical experience the resident had, the more their survey responses indicated a positive impression of the bones

Inserting screws into the vertebral pedicles is a challenging step in spinal fusion and scoliosis surgeries. Errors in placement can lead to neurological complications. The more experienced the surgeon, the better the accuracy of the screw placement. A physical training system would provide residents with the feel of performing pedicle cannulation before operating on a patient. The proposed system consists of realistic bone models mimicking the geometry and material properties of typical patients, coupled with a force feedback probe. The purpose of the present study was to determine the forces encountered during pedicle probing to aid in the development of this training system. We performed two separate investigations: [1] 15 participants (9 expert surgeons, 3 fellows and 3 residents) were asked to press a standard pedicle awl three times onto a mechanical scale, blinded to the force, demonstrating what force they would apply during safe pedicle cannulation and during unsafe cortical breach; [2] three experienced surgeons used a standard pedicle awl fitted with a one-degree of freedom load cell to probe selected thoracolumbar vertebrae of eight cadaveric specimens to measure the forces required during pedicle cannulation and deliberate breaching. A total of 42 pedicles were tested. Both studies had wide variations in the results, but were in general agreement. Cannulation (safe) forces averaged approximately 90 N (20 lb) whereas breach (unsafe) forces averaged approximately 135–155 N (30–35 lb). The lowest average forces in the cadaveric study were for pedicle cannulation, averaging 86 N (range, 23–125 N), significantly lower (p<0.001) than for anterior breach (135 N; range, 80–195 N); medial breach (149 N; range, 98–186 N) and lateral breach (157 N; range, 114–228 N). There were no significant differences between the breach forces (p>0.1). Cannulation forces were on average 59% of the breach forces (range, 19–84%) or conversely, breach forces were 70% higher than cannulation forces. To our knowledge, these axial force data are the first available for pedicle cannulation and breaching. A large range of forces was measured, as is experienced clinically. Additional testing is planned with a six-degree-of-freedom load cell to determine all of the forces and moments involved in cannulation and breaching, throughout the thoracolumbar spine. These results will inform the development of a realistic bone model as well as a breach prediction algorithm for a physical training system for spine surgery

The anterior approach for total hip arthroplasty (THA) has been associated with a faster earlier functional recovery and has gained increasing utilization for primary THA exposure. However, some studies have suggested a higher risk of femoral complications, as well as difficulty with femoral exposure. Techniques of soft tissue releases have been described to offer better femoral exposure, and to help mitigate complications like femoral fracture or breach of the canal with broaching. However, appropriate titrated soft release remains important to decrease potential risk of dislocation. Here we present a suggested technique and hierarchy of soft tissue releases to adequately expose the femur. In addition, we discuss adjunctive table and patient position maneuvers for femoral exposure, as well as more extensile and revision techniques if necessary. For any figures or tables, please contact authors directly

Primary internal fixation of uncomplicated scaphoid fractures is growing in popularity due to its advantages over conventional cast fixation. Performing the procedure percutaneously reduces the risk of infection and soft tissue damage, but can be tricky because of the small size and complex three-dimensional (3D) shape of this bone. Computer-assisted navigation has been an invaluable tool in other pin insertion procedures. This in-vitro study aimed to evaluate two different rendering techniques for our navigation interface: (i) 3D volume rendering of the CBCT image to show digitally-reconstructed radiographs of the anatomy, and (ii) volume-slicing, analogous to CT-images. As the shape of the scaphoid is highly variable, a plastic model of the wrist was constructed in order to provide consistency that would not be possible in a cadaver-based study. The plastic model featured a removable scaphoid such that a new one was replaced between trials. Three surgeons each performed eight trials using each of the two navigated techniques (yielding a total of 48 trials for analysis). Central placement of scaphoid fixation has been linked with mechanical stability and improved clinical outcomes, thus the surgical goal was to place a K-wire to maximise both depth from the surface and length of the drill path. The wire was drilled through the scaphoid, from distal to proximal, allowing for post-trial analysis of the drill path. A ceiling-mounted OptoTrak Certus camera (Northern Digital Inc., Canada) and a floor-mounted isocentric 3D CBCT C-arm (Innova 4100, GE Healthcare, France) permitted a registration transformation between the tracking and imaging systems to be computed preoperatively, before each trial, using a custom calibration device. Optical local coordinate reference bodies were attached to the wrist model and a custom drill guide for tracking with the Certus camera. During each trial, a 3D spin image of the wrist model was acquired, and rendered according to the technique under study. For 3D volume rendering, the spin image was rendered as a digitally-reconstructed radiograph (DRR) that could be rotated in three dimensions. In the planning phase, the surgeon positioned a desired drill path on the images. Anterior-posterior and lateral views of the 3D volume rendering were used for navigation during the drilling phase. The real-time orientation of the drill guide was shown relative to these images and the plan on an overhead. For volume-sliced (VS) navigation, the spin image was volume-rendered and sliced along the principal planes (axial, coronal, sagittal) for planning. A slider interface allowed the surgeon to scroll through the slices in each of the planes, as if they were looking at individual CT slices. Once the desired drill path was positioned, the volume-sliced views were reconfigured to show slices along the oblique planes of the planned path for navigation. Following all trials, model scaphoids with wire intact were imaged using CT with a slice thickness of 0.625 mm. The CT series were segmented and used to construct 3D digital models of the wire and drilled scaphoid. Algorithms were developed to determine the minimum distance from the centerline of the wire and the scaphoid surface, and to compute the length of the drill path. Screw breach should be avoided as it disrupts the articular surface and may lead to a sequela of cartilage deterioration and osteoarthritic changes. The shortest distance measure was extrapolated to assess whether a standard fixation screw (Accutrak Mini, 1.78 mm radius) would have breached the scaphoid surface. There were three screw breaches noted in the 3D DRR trials, while only one occurred using volume-slicing. The minimum distance from the centerline of the wire to the scaphoid surface can also be thought of as a “safe zone” for screw breach. Although no difference in the mean distance (μ) was noted between groups (μ. DRR. = 2.3 mm, μ. VS. = 2.2 mm), the standard deviation (σ) was significantly higher for the DRR trials (σ. DRR. = 0.50 mm, σ. VS. = 0.37 mm, p < 0.1), suggesting a higher reliability of central placement using VS for navigation. In contrast, the length of the drill paths were significantly longer for the DRR trials (μ = 28.7 mm, σ = 0.66 mm) than for VS-navigation (μ = 28.3 mm, σ = 0.62 mm) at p < 0.1. The surgical goal was to pick a path that maximised both the length of the path, as well as the minimum distance from the scaphoid surface. Algorithms were developed to find the paths that would maximise: (i) the length and (ii) the distance from the surface of the model scaphoid used in this study. The maximum possible length was 29.8mm (with a minimum distance of 2.2mm from the scaphoid surface), and the maximum distance was 3.3mm (with a length of 27.5mm). Therefore, the set of optimal drill paths had length > 27.5 mm, and distance > 2.8 mm. Of the DRR-navigated trials, 11 were below the minimum optimal depth, and only one trial was below the optimal length; 13 of the 24 trials (54%) were of both optimal length and depth. Of the VS-navigated trials, nine were below the minimal optimal distance, and four were below the minimum optimal length; 11 out of 24 trials (46%) were within both the optimal length and depth. From this comparative study, we conclude that VS-navigation was superior in locating a central location for the fixation wire, while DRRs were superior in maximising the depth of the drill path. Thus, we propose a hybrid interface, incorporating both volume-slicing and DRRs, in order to maximise the effectiveness of navigation for percutaneous scaphoid pinning

Introduction. Successful designs of total hip replacement need to be robust to surgery-related variability. Until recently, only simple parametric studies have explored the influence of surgical variability [1]. This study presents a systematic method for quantifying the effect of variability in positioning on the primary stability of femoral stems using finite element (FE) models. Methods. Patient specific finite element models were generated of two femurs, one male and one female. An automated algorithm positioned and sized a Corail stem (DePuy Synthes, Warsaw) into each of the femurs to achieve maximum fill of the medullary canal without breaching into the cortical bone boundaries.. Peak joint contact and muscle forces associated with level gait were applied[2] and scaled to the body mass of each subject, whilst the distal femur was rigidly constrained. The space prone to surgical variation was defined by the “gap” between the stem and the inner boundary of the cortical bone. The anterior/posterior and the varus/valgus alignment of the stem within this “gap” was controlled by varying the location of the points defining the shaft axis. The points were taken at 20% and 80% of the stem length (Figure 1). The anteversion angle as well as the vertical and the medial position of the stem were controlled by changing the location of the head centre within the femoral head radius. The location of these points was varied using Latin Hypercube sampling to generate 200 models per femur, each with a unique stem position. The risk of failure was evaluated based on stem micromotion, equivalent strains, and percentage of the bone-prosthesis contact area experiencing more than 7000 µstrains [3]. Results. The range of positions covered in this study adhered to the anatomy of the subjects (Table 1) and none of the stem positions breached into the cortical bone of the femur. The 90th percentile peri-prosthetic strains were between 1770 – 4792 µstrains for the male subject, and 2710 – 11260µstrains for the female subject. The 90th percentile micromotion was between (15.6 – 47) µm for the male subject, and (42.4 – 102.4) µm for the female subject. The percentage of the contact area experiencing more than 7000 µstrains was between (0% – 0.33%) for the male subject, and (0% – 12%) for the female subject. Discussion. A systematic method for studying the effect of surgical-related variation on primary stability was presented its applicability demonstrated on two femurs. The study found that variation in stem position may result in large variation (up to 1.5 times the baseline position) in strains and micromotions. The magnitude Up to three times the magnitudes for the ideal stem position. This method can be applied to larger samples to understand the influence of different alignment parameters on the primary stability of femoral stems

Introduction. Orthopaedic departments are increasingly put under pressure to improve services, cut waiting lists, increase efficiency and save money. It is in the interests of patients and NHS organisations to ensure that operating theatre resources are used to best effect to ensure they are cost effective, support the achievement of waiting time targets and contribute to a more positive patient experience. Patients in the UK are expected to have undergone surgery once decided within 18 weeks. A good system of planning and scheduling in theatre enables more work, however is largely delegated to non-clinical managerial and administrative staff. After numerous cancellations of elective cases due to incomplete pre-operative work-up, unavailable equipment and patient DNAs, we decided to introduce a surgeon-led scheduling system. Intervention. The surgeon-led scheduling diary involved surgeons offering patients a date for surgery in clinic. This allowed for appropriate organisation of theatre lists and surgical equipment, and pre-operative assessment. Results. Prior to surgeon-led scheduling, there were a high number of patient DNAs (11%) and cancellations (15%), and 18-week target breaches (16%). Theatre utilisation was found to be 76%, with a booking efficiency of 80%. With surgeon-led scheduling, the number of cancellations reduced significantly (7%) although theatre utilisation remained similar (75%). Booking efficiency was reported to be 97%. There was a shorter waiting time by approximately 3 weeks and only 3% of patients breached their 18-week target. Patients, theatre staff and surgeons were also surveyed. 100% of patients were satisfied with a date being offered in clinic, with 80% feeling less inclined to change or cancel the date of surgery. 100% of theatre staff were satisfied with the system, with improved communication and time to allocate surgical resources. 90% of surgical trainees reported improved satisfaction due to the mixed case-load and increased time for training. Conclusion. In hospitals, optimising utilisation of operating theatres is essential both for patient care, efficiency and economy. We believe a surgeon led scheduling diary improves the patient experience in addition to surgical team satisfaction and morale

Introduction. Pedicle screw fixation commonly uses a manual probe technique for preparation and insertion of the screw. However, the accuracy of obtaining a centrally located path using the probe is often dependent on the experience of the surgeon and may lead to increased complications. Fluoroscopy and navigation assistance improves accuracy but may expose the patient and surgeon to excessive radiation. DSG measures electrical conductivity at the tip and provides the surgeon with real-time audio and visual feedback based on differences in tissue density between cortical and cancellous bone and soft tissue. The authors investigated the effectiveness of DSG for training residents on safe placement of pedicle screws. Methods. 15 male cadaveric thoracolumbar spine specimens were fresh-frozen at the time of expiration. Residents were assigned 3 specimens each and randomised by pedicle side and order of technique for pedicle screw placement (free-hand versus DSG). Fluoroscopy and other navigation assistance were not used for pedicle preparation. All specimens were imaged using CT following insertion of all pedicle screws. The accuracy was assessed by a senior radiologist and graded as within (≤ 2mm breach) or outside (> 2mm breach) the pedicle. Results. 15 specimens were dissected in standard fashion to expose the thoracolumbar spine (T7-L5). 5 residents were randomised and assigned 3 specimens each to prepare bilateral pedicles from T8 to L5 (60 pedicles per resident) using either PediGuard or free-hand technique. A total of 249 pedicle screws were placed. Post-procedure CT scans demonstrated 214 (85.9%) screws within the pedicle. Breach rate for the DSG group was 8.2% and 19.7% for the non-DSG group, with an overall reduction of 58% (p=0.025). Conclusion. The use of Dynamic Surgical Guidance decreased the pedicle screw placement learning curve in residents, while improving breach rate by 58%. This study demonstrates that DSG has the potential for resident education and refinement in operative technique

We prospectively studied the use of intercostal EMG monitoring as an indicator of the accuracy of the placement of pedicle screws in the thoracic spine. We investigated 95 thoracic pedicles in 17 patients. Before insertion of the screw, the surgeon recorded his assessment of the integrity of the pedicle track. We then stimulated the track using a K-wire pedicle probe connected to a constant current stimulator. A compound muscle action potential (CMAP) was recorded from the appropriate intercostal or abdominal muscles. Postoperative CT was performed to establish the position of the screw. The stimulus intensity required to evoke a muscle response was correlated with the position of the screw on the CT scan. There were eight unrecognised breaches of the pedicle. Using 7.0 mA as a threshold, the sensitivity of EMG was 0.50 in detecting a breached pedicle and the specificity was 0.83. Thoracic pedicle screws were accurately placed in more than 90% of patients. EMG monitoring did not significantly improve the reliability of placement of the screw

The use of cervical pedicle screws as anchors in posterior reconstruction surgery has not been widely accepted due to the neurological or vascular injury. We thus sought to investigate the accuracy of free-handed pedicle screw placement in the cervical and upper thoracic spine at the early stage of clinical application. Eight patients (five males and three females) were included in this study. Mean age was 63 years (31 to 78 years). There were three patients with rheumatoid arthritis, three with cervical fracture-dislocation, and two with spinal metastasis. Twenty-four pedicle screws (3.5 mm diameter: Vertex, Medtronic Sofamordanek) were placed into the pedicle from C2 to T2 level by free-handed technique2). Grade of breaching of pedicle cortex was divided into four groups (Grade 0–3). In addition, screw axis angle (SAA) were calculated from the horizontal and sagittal CT images and compared with pedicle transverse angle (PTA). Furthermore, perioperative complications were also examined. Our free-handed pedicle screw placement with carving technique is as follows: A longitudinal gutter was created at the lamina-lateral mass junction and then transverse gutter perpendicular to the longitudinal gutter was made at the lateral notch of lateral mass. The entry point of the pedicle screw was on the midline of lateral mass. Medial pedicle cortex through the ventral lamina was identified using the probes to create the hole within the pedicle. The hole was tapped and the screw was gently introduced into the pedicle to ensure the sagittal trajectory using fluoroscopy. In the transverse direction, 22 out of 24 screws (92%) were entirely contained within the pedicle (Grade 0). In contrast, only teo screws (8%) produced breaches less than half the screw diameter (Grade 1). In the sagittal direction, all screws were within the pedicle (Grade 0). Screw trajectories were not consistent with anatomical pedicle axis angle; the mean SAA were smaller than the mean PTA at all levels. The pedicle diameter ranged from 3.9 to 9.2 mm. The mean value gradually increased toward the caudal level. There were no neurological and vascular complications related to screw placement

There were 70000 people admitted to hospital with fractured hips in 2007 and the incidence is rising by 2% each year. Hip fractures represent significant morbidity and mortality to patients and cost the NHS £1.8 billion annually. In 2008 the British Orthopaedic Association Standards for Trauma (BOAST) issued a 14-point guideline to be followed for the management of hip fractures. The aim was to improve secondary prevention of osteoporosis, reduce the falls risk and further fractures. This aimed to provide better care to improve the outcomes for patients and reduce the burden of hip fractures on society. The aim of the audit was to see if the BOAST guidelines are met before and after the transition to a level 1 MTC (Major Trauma Centre) and to measure any impact the change had. Methods: Prospective data was collected for three months in 2010, 2011 and 2012. 94 case notes were reviewed and compared to the outcomes laid out in the BOAST guidelines to see if standards were met. Overall adherence to the guideline's recommendations was high throughout the 3 sample months. For each of the 3 sample months 100% adherence was seen in all of the following criteria: further imaging if x-rays unclear, appropriate analgesia, pre-op assessment, seniority of surgeon, orthogeriatrician involvement, seniority of surgeons and submission to the National Hip Fracture Database. The main common area where adherence was less than 100% was with A and E breaches (i.e. greater than 4 hours referral to the ward). Despite relocation and transition to a level 1 MTC, the management of fractured neck of femur patients compared to the BOAST guidelines remained of a high standard. Further improvements have also been made since moving to the new hospital site where shortcomings in management have been identified. Improvements from year one to three include prophylactic antibiotics and warfarin reversal; there is now a new trust protocol in place for warfarin reversal in the case of hip fractures. Elsewhere adherence to the guidelines remains high across the sample months. Confirming that despite moving to a level 1 status the trauma team continues to be performing well and managing this group appropriately. In January 2012 BOAST published a second version of the hip fracture guidelines: A and E breaches were removed from the guidelines. There have also been several new additions to the guidelines, which prompt a further re-audit in the future

Simulation is an effective adjunct to the traditional surgical curriculum, though access to these technologies is often limited and costly. The objectives of this work were to develop a freely accessible virtual pedicle screw simulator and to improve the clinical authenticity of the simulator through integration of low-cost motion tracking. The open-source medical imaging and visualisation software, 3D Slicer, was used as the development platform for the virtual simulation. 3D Slicer contains many features for quickly rendering and transforming 3D models of the bony spine anatomy from patient-specific CT scans. A step-wise pedicle screw insertion workflow module was developed which emulated typical pre-operative planning steps. This included taking anatomic measurements, identifying insertion landmarks, and choosing appropriate screw sizes. Monitoring of the surgeon's simulated tool was assessed with a low-cost motion tracking sensor in real-time. This allowed for the surgeon's physical motions to be tracked as they defined the virtual screw's insertion point and trajectory on the rendered anatomy. Screw insertion was evaluated based on bone density contact and cortical breaches. Initial surgeon feedback of the virtual simulator with integrated motion tracking was positive, with no noticeable lag and high accuracy between the real-world and virtual environments. The software yields high fidelity 3D visualisation of the complex geometry and the tracking enabled coordination of motion to small changes in both translational and angular positioning. Future work will evaluate the benefit of this simulation platform with use over the course of resident spine rotations to improve planning and surgical competency

Introduction. Pre-clinical testing of orthopaedic devices could be improved by comparing performance with established implants with known clinical histories. Corail and Summit (DePuy Synthes, Warsaw) are femoral stems with proven survivorship of 95.1% and 98.1% at 10 years [1], which makes them good candidates as benchmarks when evaluating new stem designs. Hence, the aim of this study was to establish benchmark data relating to the primary stability of Corail and Summit stems. Methods. Finite Element (FE) simulations were run for 34 femurs (from the Melbourne femur collection) for a diverse patient cohort of joint replacement age (50 – 80 yrs). To account for the diversity in shape, the cohort included femurs with the maxima, minima and medians for 26 geometric parameters. Subject-specific FE models were generated from CT scans. An in-house developed algorithm positioned idealized versions of Corail and Summit (Figure 1) into each of the femur models so that the stem and femur shaft axes were aligned, and the vertical offset between the trunnion centre and the femoral head centre was minimised. For such a position, the algorithm selected the size that achieved maximum fill of the medullary canal without breaching the cortical bone boundaries. Joint contact and muscle forces were calculated for level gait and stair climbing[2] and scaled to the body mass of each subject. Femurs were rigidly constrained at the condyles. Risk of failure was assessed based on (i) stem micromotion, (ii) equivalent strains (iii) percentage of the bone-prosthesis contact area experiencing micromotions < 50 μm, micromotions > 150 μm and strains > 7000 μstrains [3]. Results. Stair climb loads resulted in higher micromotion and interface strains, compared to level gait loads. For level gait, on average, Corail had 89% and Summit had 91% of the contact area experiencing less than 50 μm and less than 1% of the contact area with micromotion greater than 150 μm. For stair climbing, the average area experiencing <50 μm was about 75% for both stems. On average, Corail and Summit had less than 1% of the contact area with micromotion greater than 150 μm during stair climbing. The average percentage of the contact are with strains greater than 7000 μstrains was about 2% for both stems during level gait, and 8% (Corail), 10% (Summit) during stair climbing (Figure 2). Discussion and Conclusion. It is desirable for the micromotion at the entire contact area to be below 50 μm. Despite the reported good survivorship of Corail and Summit [1], results of the FE simulations do not show such a distribution. Instead, results suggest that primary stability may be achieved with up to 25% of the contact area with micromotion greater than 50 μm. Hence, the 75th percentile may be a suitable metric for benchmarking femoral stems

Developmental dysplasia of the hip (DDH) is relatively a common condition that can lead to early arthritis of the hip. Although total hip arthroplasty is the surgical treatment of choice for these patients with end stage arthritis, some patients afflicted with DDH may present early. Acetabular osteotomy, in particular Bernese or periacetabular osteotomy (PAO as described by Professor Ganz and Jeff Mast back in 1980s) may be an option with patients with symptomatic DDH who have joint space available. PAO has many advantages. First, it is performed through a single incision (modified Smith Peterson approach) without breaching the abductor mechanism. The periacetabular fragment has, hence, excellent blood supply and avascular necrosis of the acetabular portion is not an issue. In addition, the osteotomy is so versatile allowing for great mobility of the fragment to obtain coverage even in the worst of circumstances. The osteotomy does not affect the posterior column and hence allows for earlier weight bearing. Most joint preservation surgeons in North America and Europe prefer PAO to other types of osteotomy. The indications for PAO are a patient with symptomatic DDH who has good joint space and a congruent joint. The congruency of the joint is usually determined by the abduction views (obtained at 30 degrees abduction and neutral rotation). Although the joint space may be measured on plain radiographs, in recent years some centers have been utilising cross sectional imaging, such as dGEMERIC for evaluation of the articular cartilage, which has been shown to be a good predictor of outcome for PAO

Avascular necrosis of the femoral head (AVN) is associated with collapse of the femoral head and arthritic degeneration of the joint. The combination of an implant inserted into the femoral head that provides mechanical support and bone grafting to promote bone formation may offer a possible joint-preserving solution1. Seventeen such procedures were performed between November 2012 and March 2014 during an IRB approved clinical trial. Thirteen out of 18 patients remained unrevised at a minimum of 12 months; the results of radiographic and histological analysis of four revisions are presented. The investigational device (Figure 1) was developed as a joint preserving treatment for AVN with a clinical grade of IIC or less according to the ARCO grading system2. The device consisted of a braided spherical Nitinol cage with a Titanium / Nitinol orientation feature. It was implanted using fluoroscopic navigation into a spherical cavity cut into the femoral head via an 11mm diameter access tunnel. Once deployed, the implant was filled with a lightly impacted mixture of autologous bone graft and bone marrow soaked Conduit TCP (DePuy CMW, Blackpool, UK). The implant's purpose was to provide mechanical support to the weakened subchondral surface while the bone graft mixture re-integrated with the host bone. The retrieved femoral heads were trimmed to leave approximately 3mm of bone around the implant, dehydrated, embedded in methacrylate resin, sectioned and thinned into 50–70µm coronal slices for histological analysis. The following observations were made (Figure 2):. Case 1 (Female, age 70, ARCO IIB, revised after 2 days): The patient was revised for spontaneous sub-trochanteric fracture secondary to osteoporosis. Contact between the native bone and bone graft was observed. Marrow elements and repair tissue were visible within the pores in the graft (Figure 2a). Case 2 (Male, age 67, ARCO IIIC, revised after 82 days): Two wires were broken but retained within the braided structure. A radiolucent gap caused by the presence of fibrous tissue between the graft mixture and native bone was evident suggesting that the implant was unable to prevent progression in this case. Case 3 (Female, age 70, ARCO IIC, revised after 482 days): The cavity penetrated the subchondral surface; at revision the implant was found to have breached the articular cartilage. There was partial separation of the proximal osteonecrotic fragment and no evidence of graft revascularisation or remodelling within the implant. Case 4 (Male, age 42, ARCO IIC, revised after 469 days): There was no indication of bone graft re-integration. Collapse of the necrotic bone and deformation of the implant was diagnosed from 1 year follow-up x-rays. Conclusion. This treatment has preserved the joints of fourteen patients. Of the four revised, two patients had clinical grades or bone quality contra-indicated for the device and three had lesions occupying more than 30% of the femoral head: Improved criteria for patient selection may be required. The device is only partially load-bearing and incapable of stabilising fractures: The radiolucent band associated with fibrous tissue formation may be an early indication of failure

Background. Anatomical reduction and stable internal fixation has been recommended as the standard treatment for fracture dislocations of the tarsometatarsal (Lisfranc) joint. Many methods of fixation have been utilised including K-wires and screw fixation, the latter being the preferred method as it provides a stronger more stable construct. However, the screws require removal after the injury has healed. We present a different method and technique of stabilisation utilising memory staples. The technique is extra-articular and avoids breaching the TMTJ joint surface, is simple and avoids the necessity of removal of hardware. Methods. 11 patients with isolated ligamentous Lisfranc injuries were treated with memory staple fixation over the past 4 years at our centre. Patients' outcome was assessed with use of the Foot & Ankle Disability Index (FADI) Score, the American Foot & Ankle Score, radiographic and clinical follow-up at an average time of 2 years post surgery. Results. The average FADI score was 86.4 (on a scale of 100 points, with 100 points indicating an excellent outcome). The average American Foot & Ankle score was 90 out of a 100. All patients demonstrated stable long term reduction of the TMT joints and none have required subsequent fusion. In all but 1 patient, there had been fatigue failure of the memory staples making hardware removal unnecessary. Conclusion. Internal fixation of Lisfranc joint fracture-dislocation with memory staples is an effective fixation method with results comparable to conventional screw fixation with the added benefit of alleviating the need for further surgery to remove the metal work

Introduction. Surgical spacesuits are in widespread use. Only one previous study (JBJS 1998) has assessed the quality of the environment within the space suit. They demonstrated that surgical spacesuits could allow re-breathing of carbon dioxide (CO. 2. ). However, they had no control group and performed a vigorous exercise protocol which may have been an unfair test. The design of helmet systems has also evolved in the last decade. We have conducted the first investigation into CO. 2. levels inside the modern space suit. There is a Workplace Exposure Limit for inspired CO. 2. as determined by the Health and Safety Executive (UK), which is 0.506kPa. We wondered whether re-breathing of CO. 2. in space suits would lead to inspired CO. 2. which breaches this level. Methods. We used an anaesthetic room gas analyzer via nasal cannulae to measure inspired (ICO. 2. ) levels in 12 healthy volunteers. Readings were taken while wearing a surgical space suit with the fan on high and low settings. These were compared with a normal surgical facemask. Readings were repeated on mild exertion to simulate the effort of performing arthroplasty surgery. Results. [Frequency of ICO2 >0.5kPa (12 subjects)]. Discussion. Despite the design modifications, modern space suits allow re-breathing of CO. 2. This is more marked with exertion and with low fan settings where ICO. 2. can exceed workplace limits. This may account for symptoms of headache and drowsiness reported after a prolonged period in the suit during arthroplasty surgery. We recommend the use of high fan settings at all times

Purpose of the study. Percutanous acetabular surgery is a new and developing technique in fixation of acetabulum fractures. The most common screw used is the anterior column screw that traverses anterograde or retrograde through the anterior column of the acetabulum. Standard height and width calculations derived from CT scans do not take the trajectory of the screw into consideration. They have been shown to exaggerate the available safe bone corridor for screw passage. Posterior column screws can be placed in a retrograde fashion via the ischial tuberosity to fixate posterior column. Limited international data is available and no studies to date have been conducted on the South African population. This study assesses the anterior and posterior acetabular columns of South African individuals and ascertains the safe bone corridor sizes. Methods. Pelvic CT-scans of 100 randomly selected patients were reviewed. Specific computer software was used to virtually place anterior screws through the anterior acetabular column, in its clinical trajectory. Specific entry points inferior to the pubic tubercles significantly changed the relation of the screw trajectory to the mid- column isthmus and were incorporated in the measurement of the anterior column. All the available lengths and diameters were measured and averages were calculated for males and females. Results. On average, males have longer and larger diameter anterior columns. The entry point on the pubic tubercle has a significant impact on the relative diameter at the mid- column. Not all commercially available cannulated screw diameters are safe to place into the anterior column. Conclusion. Although the international literature shows that percutaneous anterior column fixation is of value for early mobilisation after fractures, intimate knowledge of the local data regarding the available safe corridors for screw passage is limited. This study shows the safe bone corridors that can be used to avoid breaching the cortex during screw insertion. It also recommends safe screw diameters. NO DISCLOSURES

Introduction. A recent retrospective study of distal femoral physeal fractures (DFPFs) suggested closed manipulation alone has a high incidence of re-displacement, malunion or physeal bar formation. The paper concluded that all displaced DFPFs require internal fixation, and breaching the physis with k-wires is safe. We agree that hyper-extension/flexion injuries need stabilisation using k-wires but, in our experience, purely valgus/varus deformities can be successfully managed by manipulation under anaesthesia (MUA) and a moulded cylinder cast. Method. We prospectively observed DFPFs presenting over 12 months. Departmental policy is to treat varus/valgus deformities by MUA, with cylinder casting providing 3 point fixation. Hyper-extension/flexion injuries are reduced on a traction table. 2mm cross k-wiring is performed, leaving the wires under the skin, and a cylinder plaster applied. A post-operative CT scanogram accurately assesses limb alignment. Patients are mobilised immediately using crutches and weight-bearing as pain allows. Plaster and k-wires are removed after 4–5 weeks. Scanogram is then repeated, and again at 6 months and 1 year. Results. 17 cases presented over 1 year. 16 were male, with a median age of 15. 13 were injured playing soccer, 1 in a motor vehicle accident and 3 by other mechanisms. Internal fixation supplemented reduction in 13 cases. 1 patient required repeat MUA and k-wiring when post-operative scanogram identified significant varus mal-alignment. In all cases, cylinder casting was unproblematic and range of movement quickly recovered after plaster/wire removal. To date none have developed significant malunion or growth arrest requiring intervention. Conclusion. DFPFs are uncommon, almost always occurring in teenage males. Accurate reduction and stabilisation is vital to restore and maintain a correct mechanical axis. MUA and cylinder casting is adequate in appropriate cases. Early imaging with CT scanogram can detect mal-alignment. Growth arrest is unusual and unlikely to be significant in most patients, who are approaching skeletal maturity. NO DISCLOSURES

Purpose. Surgical complications are common and frequently preventable. The introduction of the WHO Surgical Safety Checklist has improved surgical outcomes. WHO guidelines reduce, but do not prevent errors. Successful arthroplasty surgery requires strict infection control measures. We observed a single surgical team to see if errors caused by operating room personnel were covered by the WHO Checklist. Method. Two independent observers studied compliance of WHO Checklists and operating room etiquette, for one surgical team. All operating room personnel were observed during thirteen arthroplasties (hips and knees) from induction to recovery. All Personnel were blinded to the purpose of this study. Data was categorised into errors with WHO checklists and operating room etiquette. Results. 120 errors were observed in thirteen cases, none of these errors affected patient outcome and they were all corrected promptly. 113 (94%) were operating room etiquette errors and 7 (6%) were WHO checklist errors. Types of operating room etiquette errors which occurred were 32% laminar flow errors, 27% sterility errors and 20% operating room attire errors. Eleven arthroplasties were signed off as WHO Checklist compliant and two arthroplasties were observed prior to the introduction of WHO checklists. Despite going through the checklist, in seven of the eleven cases subsequent errors were found which should have been identified during the initial surgical pause: two imaging errors, two implant error and three other patient safety errors. Conclusion. The majority of errors are breaches of operating room etiquette, all being infection control issues in arthroplasty procedures. Many of these errors are not covered by the WHO Checklists. Standardised teaching of operating room etiquette may reduce these. The development of a specific arthroplasty checklist may optimise patient safety