We aim to determine the differences in lower limb joint kinematics during the golf swing of patients who had undergone Total Knee Arthroplasty (TKA) and a control group of native knee golfers. A case-control study was undertaken with ten golfers who had undergone TKA (cruciate retaining single radius implant) and five age and matched golfers with native knees. Each golfer performed five swings with a driver whilst being recorded at 200Hz by a ten-camera motion capture system. Knee and hip three-dimensional joint angles (JA) and joint angular velocities (JAV) were calculated and statistically compared between the groups at six swing events. The only significant differences in knee joint kinematics between TKA and control groups was a lower external rotation JA in the left knee during the backswing (p=0.010). There was no significant difference in knee JAV between the groups. Both hips demonstrated significantly (p=0.023 for left and p=0.037 for right) lower flexion in the TKA group during the takeaway swing event, and there was lower internal rotation in the backswing and greater external rotation in the downswing of the right hip. There was also slower left hip extension JAV in the downswing. Normal knee kinematics were observed during the golf swing following TKA, with the exception of reduced external rotation in the left knee during the back swing and the right during the down swing. The differences demonstrated in the hip motion indicate that they may make compensatory movements to adjust to the reduced external rotation demonstrated in the knee

Background. Sterile Surgical Helmet System (SSHS) are used routinely in hip and knee arthroplasty in order to decrease the risk of infection. It protects surgeon from splash and also prevents contamination of surgical field from reverse splash by virtue of its perceived sterility. A prospective study was conducted to confirm if SSHS remain sterile throughout the procedure in Hip (THA) and Knee (TKA) Arthroplasty. We also evaluated if type of theatre had any effect on degree of contamination. Material and Methods. Visor area of 40 SSHS was swabbed at half hourly interval until the end of the procedure. Two groups of 20 each were made on the basis of theatre used for performing surgery. Group 1 (Gp1) had surgery performed in laminar flow and Group 2 (Gp2) in non-laminar flow theatre. Swabs collected were processed to compare the time dependent contamination of the SSHS and identify the organisms responsible for contamination. Results. Overall 80% (70% laminar, 90% non-laminar) of masks were contaminated by end of the procedure. There was a statistically significant difference in degree of contamination after direct inoculation while there was no statistical difference after 24 hrs of incubation. Coagulase negative Staphylococcus was the most common bacteria grown in both the groups. Conclusion. SSHS lose their sterility peroperatively due to airborne contamination, mandating prompt change of gloves in case of active contact with them to avoid the bacterial transmission into surgical wound and catastrophic joint infection

Introduction. Total leg muscle function in hip OA patients is not well studied. We used a test-retest protocol to evaluate the reproducibility of single- and multi-joint peak muscle torque and rapid torque development in a group of 40–65 yr old hip patients. Both peak torque and torque development are outcome measures associated with functional performance during activities of daily living. Material and Methods. Patients: Twenty patients (age 55.5±3.3, BMI 27.6±4.8) who underwent total hip arthroplasty participated in this study. Reliability: We used the intra-class correlation (ICC) and within subject coefficients of variation (CVws) to evaluate reliability. Agreement: Relative Bland-Altman 95% limits of agreements (LOA) and smallest detectable difference (SDD) were calculated and used for evaluation of measurement accuracy. Parameters: Maximal muscle strength (peak torque, Nm) and rate of torque development (Nm•sec-1) for affected (AF) and non-affected (NA) side were measured during unilateral knee extension-flexion (seated), hip extension-flexion, and hip adduction-abduction (standing), respectively. Contractile RTD100, 200, peak was derived as the average slope of the torque-time curve (torque/time) at 0–100, 0–200 and 0 peak relative to onset of contraction. Protocol: After 5 min level walking at self-selected and maximum speeds each muscle group was tested using 1–2 sub-maximal contraction efforts followed by 3 maximal contractions 4s duration. Statistics: The variance components were estimated using STATA12, with muscle function and occasion as independent variable and patients as random factor, using the restricted maximum likelihood method (=0.05). Results. For all exercises and sides, the ICC's for peak torque were good (0.81–0.96) with CVws ranging from 5.0–10.8%. Similar good ICC's were observed for RTD200 on the non-affected side (0.83–0.93), whereas most exercises (4/6) on the affected side showed moderate to good ICC (0.72–0.82). We found moderate CVws for RTD200 with 12.8–18.7% and 10.3–18.9%, affected and non-affected, respectively. With few exceptions the ICC's and CVws for RTD100 were moderate to poor on the affected side but good to moderate on the non-affected side. The SDD's for peak torque ranged from 14.9 Nm to 39.0 Nm, equal to relative LOA of 13.9–23.8%. For RTD200, the SDD's were 77–257 Nm•sec-1 and 29.2–86.2%, absolute and relative, respectively. With few exceptions interventions measuring RTD100 and RTDpeak would have to find changes exceeding 60% for them to be statistical significant. Conclusions. Our novel set-up for lower limb isometric muscle testing showed overall good reproducibility for peak torque, moderate for RTD200, while poor for RTD100 and RTDpeak. The results for peak torque and RTD200 are promising for defining relevant changes in muscle function in future longitudinal clinical trials in this patient group

Aims. The aim of this study was to describe services available to patients with periprosthetic femoral fracture (PPFF) in England and Wales, with focus on variation between centres and areas for care improvement. Methods. This work used data freely available from the National Hip Fracture Database (NHFD) facilities survey in 2021, which asked 21 questions about the care of patients with PPFFs, and nine relating to clinical decision-making around a hypothetical case. Results. Of 174 centres contributing data to the NHFD, 161 provided full responses and 139 submitted data on PPFF. Lack of resources was cited as the main reason for not submitting data. Surgeon (44.6%) and theatre (29.7%) availability were reported as the primary reasons for surgical delay beyond 36 hours. Less than half had a formal process for a specialist surgeon to operate on PPFF at least every other day. The median number of specialist surgeons at each centre was four (interquartile range (IQR) 3 to 6) for PPFF around both hips and knees. Around one-third of centres reported having one dedicated theatre list per week. The routine discussion of patients with PPFF at local and regional multidisciplinary team meetings was lower than that for all-cause revision arthroplasties. Six centres reported transferring all patients with PPFF around a hip joint to another centre for surgery, and this was an occasional practice for a further 34. The management of the hypothetical clinical scenario was varied, with 75 centres proposing ORIF, 35 suggested revision surgery and 48 proposed a combination of both revision and fixation. Conclusion. There is considerable variation in both the organization of PPFF services England and Wales, and in the approach taken to an individual case. The rising incidence of PPFF and complexity of these patients highlight the need for pathway development. The adoption of networks may reduce variability and improve outcomes for patients with PPFF. Cite this article: Bone Jt Open 2023;4(5):378–384

This study aims to determine satisfaction rates after hip and knee arthroplasty in patients who did not initially respond to PROMs, characteristics of non-responders, and contact preferences to maximise response rates. We performed a prospective cohort study of 709 patients undergoing THA and 737 patients undergoing TKA in a single centre in 2018. EQ-5D health related quality of life score and Oxford Hip/knee scores (OHS/OKS) were completed preoperatively and at 1year postoperatively via post when satisfaction was also assessed. Univariate, multivariate and receiver operator curve analysis were performed. 151/709 (21.2%) hip patients were non-responders, 83 (55.0%) of whom were contactable. 108/737 (14.6%) knee patients were non-responders, 91 (84.3%) of whom were contactable. There was no difference in satisfaction after arthroplasty between initial non-responders and responders for hips (74/81 vs 476/516, p=0.847) or knees (81/93 vs 470/561, p=0.480). Initial and persistent non-response was associated with younger age, higher BMIs and significantly worse preoperative PROMS for both hip and knee patients (p=0.05). Multivariate analysis demonstrated that younger age, higher BMI and poorer pre-operative OHS were independently associated with persistent non-response to hip PROMs (p<0.05). For the entire cohort (n=1352) patients <67 years were less likely to respond to postal PROMs with OR 0.63 (0.558 to 0.711). Using a threshold of >66.4 years predicted a preference for contact by post with 65.4% sensitivity and 68.1% specificity (AUC 0.723 (0.647-0.799 95%CI, p<0.001)). Most initial non-responders were ultimately contactable with effort. Satisfaction rates were not inferior in patients who did not initially respond to PROMs

One potential approach to addressing the current hip and knee arthroplasty backlog is via adoption of surgical prioritisation methods, such as use of pre-operative health related quality of life (HRQOL) assessment. We set out to determine whether dichotomization using a previously identified bimodal EuroQol Five-Dimension (EQ-5D) distribution could be used to triage waiting lists. 516 patients had data collected regarding demographics, perioperative variables and patient reported outcome measures (pre-operative & 1-year post-operative EQ-5D-3L and Oxford Hip and Knee Scores (OHS/OKS). Patients were split into two equal groups based on pre-operative EQ-5D Time Trade-Off (TTO) scores and compared (Group1 [worse HRQOL] = −0.239 to 0.487; Group2 [better HRQOL] = 0.516 to 1 (best)). The EQ5D TTO is a widely used and validated HRQOL measure that generates single values for different combinations of health-states based upon how individuals compare x years of healthy living to x years of illness. We identified that those in Group1 had significantly greater improvement in post-operative EQ-5D TTO scores compared to Group2 (Median 0.67vs.0.19; p<0.0001 respectively), as well as greater improvement in OHS/OKS (Mean 22.4vs16.4; p<0.0001 respectively). Those in Group2 were significantly less likely to achieve EQ-5D MCID attainment (OR 0.13, 95%CI 0.07–0.23; p<0.0001) with a trend towards lower OHS/OKS MCID attainment (OR 0.66, 95%CI 0.37–1.19; p=0.168). There was no statistically significant difference in adverse events. These finding suggest that a pre-operative EQ-5D cut-off of ≤0.487 for hip and knee arthroplasty prioritisation may help to maximise clinical utility and cost-effectiveness in a limited resource setting post COVID-19

The primary aim was to assess whether patients waiting 6-months or more for a total hip (THA) or knee (KA) arthroplasty had a deterioration in their health-related quality of life (HRQoL). Secondary aims were to assess change in level of frailty and the number living in a state worse than death (WTD). Eight-six patients waiting for a primary TKA or KA for more than 6-months were selected at random from waiting lists in three centres. Patient demographics, waiting time, EuroQol 5-dimension (EQ-5D) and visual analogue scores (EQ-VAS), Rockwood clinical frailty score (CFS) and SF-36 subjective change in HRQoL were recorded at the time of and for a timepoint 6-months prior to assessment. The study was powered to the EQ-5D (primary measure of HRQoL). There were 40 male and 46 female patients with a mean age of 68 (33 to 91) years; 65 patients were awaiting a THA and 21 a TKA. The mean waiting time was 372 (226 to 749) days. The EQ-5D index deteriorated by 0.222 (95%CI 0.164 to 0.280, p<0.001). The EQ-VAS also deteriorated by 10.8 (95%CI 7.5 to 14.0, p<0.001). CFS progressed from a median of 3 to 4 (p<0.001). The number of patients WTD increased from seven to 22 (p<0.001). Thirty-one(36%) patients felt their HRQoL was much worse and 28 (33%) felt it was somewhat worse. Patients waiting more than 6-months had a clinically significant deterioration in their HRQoL and demonstrated increasing level of frailty with more than a quarter living in a health state WTD

Aims

Musculoskeletal infection is a devastating complication in both trauma and elective orthopaedic surgeries that can result in significant morbidity. Aim of this study was to assess the effectiveness and complications of local antibiotic impregnated dissolvable synthetic calcium sulphate beads (Stimulan Rapid Cure) in the hands of different surgeons from multiple centres in surgically managed bone and joint infections.

Aims

The aim of this study was to describe the demographic details of patients who sustain a femoral periprosthetic fracture (PPF), the epidemiology of PPFs, PPF characteristics, and the predictors of PPF types in the UK population.

Aims

The aim of this study was to assess the safety and clinical outcome of patients with a femoral shaft fracture and a previous complex post-traumatic femoral malunion who were treated with a clamshell osteotomy and fixation with an intramedullary nail (IMN).

Aims

The aim of this study was to describe the management and associated outcomes of patients sustaining a femoral hip periprosthetic fracture (PPF) in the UK population.

The objective of this study was to compare differences in alignment following robotic arm-assisted bi-unicompartmental knee arthroplasty (Bi-UKA) and conventional total knee arthroplasty (TKA). This was a prospective, randomised controlled trial of 70 patients. 39 TKAs were implanted manually, as per standard protocol at our institution, and 31 Bi-UKA patients simultaneously received fixed-bearing medial and lateral UKAs, implanted using robotic arm-assistance. Preoperative and 3-month postoperative CT scans were analysed to determine hip knee ankle angle (HKAA), medial distal femoral angle (MDFA), and medial proximal tibial angle (MPTA). Analysis was repeated for 10 patients by a second rater to validate measurement reliability by calculating the intra-class correlation coefficient (ICC). Mean change in HKAA towards neutral was 2.7° in TKA patients and 2.3° in Bi-UKA patients (P=0.6). Mean change in MDFA was 2.5° for TKA and 1.0° for Bi-UKA (P<0.01). Mean change in MPTA was 3.7° for TKA and 0.8° for Bi-UKA (P<0.01). Mean postoperative MDFA and MPTA for TKAs were 89.8° and 89.6° respectively, indicating orientation of femoral and tibial components perpendicular to the mechanical axis. Mean postoperative MDFA and MPTA for Bi-UKAs were 91.0° and 86.9° respectively, indicating a more oblique joint line orientation. Inter-rater agreement was excellent (ICC>0.99). Early functional activities, according to the new Knee Society Scoring System, favoured Bi-UKAs (P<0.05). Robotic arm-assisted, cruciate-sparing Bi-UKA better maintains the natural anatomy of the knee in the coronal plane and may therefore preserve normal joint kinematics, compared to a mechanically aligned TKA. This has been achieved without significantly altering overall HKAA

To validate the Modified Forgotten Joint Score (MFJS) as a new patient-reported outcome measure (PROM) in hip and knee arthroplasty (THR/TKR) against the UK's gold standard Oxford Hip and Knee Scores (OHS/OKS). The MFJS is a new assessment tool devised to provide a greater discriminatory power, particularly in well performing patients. It measures an appealing concept; the ability of a patient to forget about their artificial joint in everyday life. Postal questionnaires were sent out to 400 THR and TKR patients who were 1–2 years post-op. The data collected from the 212 returned questionnaires was analysed in relation to construct and content validity. 77 patients took part in a test-retest repeatability assessment. The MFJS proved to have an increased discriminatory power in high-performing patients in comparison to the OHS and OKS, highlighted by its more normal frequency of distribution and reduced ceiling effects. 30.8% of patients (n=131) achieved excellent OHS/OKS scores of 42–48 this compared to just 7.69% of patients who achieved a proportionately equivalent MFJS score of 87.5–100. The MFJS proved to have an increased test-retest repeatability based upon its intra-class correlation coefficient of 0.97 compared to the Oxford's 0.85. The MFJS provides a more sensitive tool in the assessment of well performing hip and knee arthroplasties in comparison to the OHS/OKS. The MFJS tests the concept of awareness of a prosthetic joint, rather than pain and function and therefore should be used as adjunct to the OKS/OHS

Background. Severe infantile Blount's disease can result in a multiplanar deformity of the proximal tibia with both intra-articular and metaphyseal components. Correction can represent a significant surgical challenge. We describe our results using the Taylor spatial frame for acute tibial hemiplateau elevation combined with gradual metaphyseal correction in patients with severe infantile blounts with an associated physeal bony bar. Methods. Eight patients (10 knees) underwent tibial hemiplateau elevation and metaphyseal correction with use of the Taylor Spatial Frame between 2012–2016. We undertook a retrospective case note and radiographic review of all patients to assess clinical and radiographic outcomes. Mean age at the time of surgery of was 11.7 years and mean length of follow up was 16.8 months. Results. At time of latest follow up all patients reported no hip, knee or ankle pain. All knees were clinically stable without lateral thrust during gait. Improvement in radiographic parameters was seen in all patients. The mean tibiofemoral angle improved from −28.3 to 5.9 degrees post operatively. The angle between femoral condyles and the tibial shaft improved from a mean of 56.3 degrees to 90.3 degrees. The joint depression angle was also seen to improve from mean 47.4 degrees to 9.8 degrees. No significant complications were seen. Conclusion. This technique has been shown to be an effective method of correction of the complex deformity encountered in severe infantile Blount's disease. Use of the Taylor spatial frame may provide certain advantages in comparison to previously described approaches. Level of Evidence: Level IV (Case Series)

Objectives. Establishing the diagnosis of implant-associated infections is often difficult, because of variable clinical presentations and lack of uniform diagnostic criteria. Sonication of removed orthopedic devices was shown to have superior sensitivity and specificity for infection. We evaluated the value of microcalorimetry as a quick and reliable tool in the diagnosis of infection in sonication fluid from removed implants. Methods. Between 10/2009 and 02/2010 we prospectively included all removed orthopaedic devices at our institution, which were subjected to sonication. Periprosthetic tissue cultures were performed as standard procedure. The removed device was sonicated in Ringer solution (40 kHz, 1 minute) and the resulting fluid was cultured and centrifuged (3000 × g, 10 minutes). The resulting pellet was resuspended in 3 ml tryptic soy broth for isothermal microcalorimetry (sensitivity of 0.25 μW). The detection time until increase of 20 μW was calculated. A 48-channel batch calorimeter (TA Instruments, New Castle, DE, USA) was used to measure the heat flow at 37°C controlled at 0.0001 °C. Results. 39 cases were included (24 males, mean age ± SD was 63 ± 16 years). 29 cases were orthopedic prostheses (14 hip, 11 knee, 1 shoulder and 1 joint spacers) and 10 cases osteosynthetic materials (6 screws, 3 plates, 1 cement-nail). 13 cases (33%) were infected, of which 10 (77%) were positive in sonication culture and 12 (92%) in microcalorimetry. The mean detection time by microcalorimetry was 11.4 h (range, 0.2 h–20.9 h). Examples for microcalorimetric signals can be seen in Fig.1. Conclusions. Microcalorimety of sonication fluid showed superior sensitivity for the diagnosis of infection with detection time of <24 h. This method is a promising diagnostic assay for a rapid and accurate diagnosis of infections associated with orthopedic devices

Background. The aim of the study was to assess the outcome of internal fixation using two ordinary plates with autogenous bone grafting in the management of non-union of femoral shaft fractures over a period of eleven years. Method. A retrospective study of double plating and autogenous bone grafting for un-united femoral shaft fractures performed by the two Senior Authors between 1996 and 2007. During this period, twenty-one cases were carried out. Details of preoperative, intra-operative, and postoperative findings were assessed. Postoperative follow up was recorded over a period of minimum two years. The procedure was performed using two ordinary plates; a broad lateral and narrow anterior plates. Autogenous cancellous grafts from iliac crest were used in all of the cases, and in some, half fibulas were inserted through the medullary canal of the femur. Results. A total of twenty-one patients were included in the study. All of them received previous treatment. The primary treatment was by intramedullary nailing in thirteen patients, uni-plating in four, external fixator in three, and traction in one. The average age was 32 (range from 16 to 52). The average interval between the initial fracture and the treatment of the non-unions was 13 months (range from 6 to 28 months). All wounds, both at fracture site and the graft donor site, healed primarily except one. That was at an iliac crest graft donor site, where superficial infection occurred, and was treated with antibiotics and healed 6 weeks later. All patients achieved union on an average of 16 weeks (range from 12 to 28 weeks). There has been no failure in implants. The average lower limb shortening was 0.75 cm (range from 0.5 to 1.0 cm). No one requested shoe raise. All the patients regained the preoperative range of motion at the hip and knee joints except four, who had limited flexion to 100 degrees. Conclusion. We conclude that double plating with autogenous bone grafting is not only a convenient method to treat non-union of femoral shaft fractures as it requires minimal instrumentation and equipment, but it should also be considered as a safe and accepted treatment method as postoperatively patients can be discharged early on crutches, with a high success rate. It is less expensive, an important consideration in developing countries

Introduction. Currently, a validate scale of ankle osteoarthritis (OA) is not available and different classifications have been used, making comparisons between studies difficult. In other joints as the hip and knee, the Kellgren-Lawrence (K&L) scale, chosen as reference by the World Health Organizations is widely used to characterize OA. It consists of a physician based assessment of 3 radiological features: osteophyte formation, joint space narrowing and bone end sclerosis described as follows: grade 0: normal joint; grade 1: minute osteophytes of doubtfull significance; grade 2: definite osteophytes; grade 3: moderate diminution of joint space; grade 4: joint space greatly impaired, subchondral sclerosis. Until now, the K&L scale has never been validated in the ankle. Our objective was to assess the usefulness of the K&L scale for the ankle joint, by determining its reliability and by comparing it to functional scores and to computerized minimal joint space width (minJSW) and sclerosis measurements. Additionally we propose an atlas of standardized radiographs for each of the K&L grades in the ankle. Methods. 73 patients 10 to 20 years post ankle ORIF were examined. Bilateral ankle radiographs were taken. Four physicians independently assessed the K&L grades and evaluated tibial and talar sclerosis on anteroposterior radiographs. Functional outcome was assessed with the AOFAS Hindfoot score. Bone density and minJSW were measured using a previously validated Ankle Image Digital Analysis software (AIDA). Results. The interobserver reliability, for the K&L stages was 0.60 (intraclass correlation coefficient) indicating moderate to good agreement. The mean AOFAS hindfoot score decreased substantially (p = 009) and linearly from 99.3 in K&L grade 0 to 79.5 points in K&L grade 4. The minJSW assessed by AIDA was similar among grades 0 to 2 (between 2 and 2.5mm), but significantly lower in grade 3 (1.8mm) and in grade 4 (1.1mm). A decreased minJSW less than 2mm, commonly used as a threshold for the assessment of hip and knee OA, was found in 77% of K&L grades 3–4 compared to 33% of grades 0–2, sensitivity 77.4% and specificity 66.7%. Physician based assessment revealed that subchondral sclerosis was present in 16% of K&L grade 1 patients, 52% of grade 2, 70% of grade 3 and 100% of grade 4 patients. No correlation could be found between physician based assessment and digital image analysis of subchondral sclerosis. Conclusions. Interobserver reliability in assessment of ankle OA using the K&L scale was similar to other previously described joints. OA progression correlated with functional diminution. Joint space narrowing assessed AIDA as well as the cut-off of 2mm correlated well with the K&L scale. Overall, we recommend the use of the K&L scale for the radiographic assessment of ankle OA

Introduction. Osteoarthritis (OA) of the hip and knee causes pain and functional limitations which lead to decreased physical activity level (1,2). Half of all male, and two thirds of all female, patients with early knee OA do not fulfill the recommendations for physical activity level (30 min/day of at least 5 days/week) (1). We tested the hypothesis that Scandinavian patients prior to total joint replacement had reduced actual physical activity and intensity levels compared with matched controls and that most patients did not fulfill the recommendations for physical activity. Methods. Physical activity and intensity were measured during 5 consecutive days with SenseWearTM Armband (SWA; BodyMedia, Inc., Pittsburgh, PA) in 53 patients with severe knee (n = 26) or hip (n = 27) OA prior to total joint replacement (51% women, age: 68 ± 5 years, BMI: 29.8 ± 10.2) and compared with data from 15 age-matched population-based controls (53% women, age: 68 ± 5 years, BMI: 26.9 ± 3.3). Sedentary, moderate, vigorous and very vigorous intensities were equivalent to Sense Wear Armband recordings of 3 MET, >36 MET, >69 MET, >9MET, respectively. In addition, total energy expenditure, average MET, numbers of steps/day, and the combined activity of moderate, vigorous, and very vigorous activity were calculated (min/day). Unpaired students t-test was used for between group comparisons (p < 0.05). Results. Participants wore the device for a mean ± SD of 98.5 ± 1.5% of the time. Patients spent significant less time being vigorously physically active (0.093 ± 0.082 vs. 0.156 ± 0.099 hours/day) and very vigorously active (0.015 ± 02 vs.0.028 ± 0.035 hours/day) than controls. However, no differences were observed for total energy expenditure, average MET, time spend being sedentary, and time spend being moderately physically active. The average activity of combined moderate, vigorous, and very vigorous activity for patients were 185 ± 1 min/day and 11.3% did not reach the recommended activity level. Finally, a tendency (p = 0.059) towards less steps/day was observed for patients (6778 ± 3196 vs. 8576 ± 2872 steps/day). Conclusions. Since Scandinavian OA patients prior to joint replacement show no or little decrease in physical activity, and that the majority fulfills recommendations for physical activity an increase in actual physical activity cannot be expected from surgery. This unexpected finding needs to be confirmed

Introduction. Osteoarthritis (OA) of the hip is an important cause of pain and morbidity. The mechanisms and pathogenesis of OA'sdevelopment remain unknown. Minor acetabular dysplasia and subtle variations in proximal femoral morphology are increasingly being recognized as factors that potentially compromise the joint biomechanically and lead to OA. Previous studies have shown that risk of hip OA increased as the femoral head to femoral neck ratio (HNR) decreased. Previous work has described the evolutionary change in inferior femoral neck trabecular density and geometry associated with upright stance, but no study has highlighted the evolutionary change in HNR. The aim of this study was to examine evolutionary evidence that the hominin bipedal stance has lead to alterations in HNR that would predispose humans to hip OA. Methods. A collaboration with The Natural History Museums of London, Oxford and the Department of Zoology, University of Oxford provided specimens from the Devonian, Jurassic, Cretaceous, Miocene, Palaeolithic and Pleistocene periods to modern day. Specimens included amphibious reptiles, dinosaurs, shrews, tupaiae, lemurs, African ground apes, Lucy (A. Afarensis), H. Erectus, H. Neaderthalis and humans. Species were grouped according to gait pattern; HAKF (hip and knee flexed), Arboreal (ability to stand with hip and knee joints extended) and hominin/bi-pedal. Imaging of specimens was performed using a 64 slice CT scanner. Three-dimensional skeletal geometries were segmented using MIMICS software. Anatomical measurements from bony landmarks were performed to describe changes in HNR, in the coronal plane of the different specimens over time using custom software. Measurements of HNR from the specimens were compared with HNR measurements made from AP pelvic radiographs of 119 normal subjects and 210 patients with known hip OA listed for hip arthroplasty. Results. Species from the HAKF group that ambulate via sprawling had the smallest HNR (1.10, SD: 0.09) (p<0.001). Species of the arboreal group (tree dwelling) had the biggest HNR (1.63, SD: 0.15) (p=0.006). The earliest bipedal species (1.41, SD: 0.04) had significantly bigger HNR (p=0.04) in comparison to the normal human subjects (1.33, SD: 0.08). Lower HNR was observed in the OA group (1.3, SD: 0.09). Discussion. The adoption of an upright stance during evolution has created an associated change in the femoral neck bone stock to adapt to the altered loading environment. These data would suggest that the HNR peaked in the Miocene period (10–15 million years ago). The trade-off between mobility and the bony density required to support gait has lead to a decreasing HNR throughout hominid evolution. Evolutionary theory would suggest that modern environmental pressures might pre-dispose future hominid evolution to an increased risk of hip OA

Methicillin Resistant Staphylococcus Aureus (MRSA) screening has reduced rates of MRSA infection in primary total hip (THR) and total knee (TKR) replacements. There are reports of increasing methicillin resistance (MR) in Coagulase Negative Staphylococci (CNS) causing arthroplasty infections. We examined microbiological results of all 2-stage THR/TKR revisions in Tayside from 2001–2010. 72 revisions in 67 patients were included; 30 THRs and 42 TKRs. Mean ages at revision were 89 and 72 years respectively. Male: female ratio 1.4:1.2-year survivorship for all endpoints: 96% in THRs and 88% in TKRs. 5-year survival: 83% and 84% respectively. The most common organisms were SA (30%) and CNS (29%). Antibiotic resistance was more common amongst CNS. 72% of CNS were resistant to Methicillin versus 20% of SA. 80% of CNS were resistant to Gentamicin OR Methicillin versus 20% of SA. 32% (8/72 cases or 11% overall) of CNS were resistant to BOTH Gentamicin AND Methicillin, the primary arthroplasty antibiotic prophylaxis in our region, versus 4% of SA. Harris Hip Scores and Knee Society Scores were lower post primary, prior to symptoms of infection in patients who had MR organisms cultured compared with those who had methicillin sensitive organisms. One-year post revision both groups recovered to similar scores. Our data suggest MR-CNS cause significantly more arthroplasty infections than MRSA. Patients developing MR infections tend to have poorer post-primary knee and hip scores before symptoms of infection fully develop. 32% of CNS causing arthroplasty infections in our region are resistant to current routine primary antibiotic prophylaxis