Aims

This study investigates head-neck taper corrosion with varying head size in a novel hip simulator instrumented to measure corrosion related electrical activity under torsional loads.

We aimed to examine outcomes between displaced femoral neck fracture (FNF) patients managed with total hip arthroplasty (THA) or hemi-arthroplasty (HA) via the anterolateral vs. posterior approach. We used data from the HEALTH trial (1,441 patients aged ≥50 with displaced FNFs randomized to THA vs. HA). We calculated each patient's propensity to undergo arthroplasty via the posterior approach, and matched them to 1 control (anterolateral approach) based on age (±5 years), and propensity score. We used Chi-Square/Fisher-Exact tests to compare dichotomous outcomes, and repeated measures ANOVA to examine differences in patient-reported outcomes (via the WOMAC subscores) from baseline to one-year postoperative. We used logistic regression to identify independent predictors of reoperation for instability in the posterior group. We identified 1,306 patients for this sub-analysis, 876 (67.1%) who received arthroplasty via an anterolateral approach, and 430 (32.9%) a posterior approach. The unadjusted rate of reoperation was significantly higher in the posterior group (10.7% vs. 7.1%). Following propensity score matching, we retained 790 patients (395 per group), with no between-group differences in patient, fracture, or implant characteristics. The matched cohort had a higher rate of comorbidities, and were less likely to be employed vs. the unmatched cohort. The rate of treatment for dislocation remained higher in the posterior group (6.1% vs. 2.0%) following matching. Repeated measures ANOVA revealed significantly better WOMAC pain, stiffness, function, and total scores in the posterior group. Between-group differences at 12-months were: pain - 0.59 (0.03–1.15); stiffness - 0.62 (0.35–0.87); function - 2.99 (0.12–5.86); total - 3.90 (0.24–7.56). We identified THA (vs. HA, odds ratio 2.05 [1.05–4.01]) as the only independent predictor of treatment for dislocation in the posterior group. Our analyses revealed that compromised patients with displaced FNFs who undergo arthroplasty via the posterior approach may report better symptoms at one-year vs. the anterolateral approach, despite a higher odds of reoperation for instability

Hypermobility Spectrum Disorder (HSD or hEDS) is attributed to a collagen abnormality associated with excessive joint flexibility. Approximately 90% of females with hip dysplasia have hypermobility. Manifestations of hypermobility in various body systems are unique to every patient, affecting different tissues of the body with varying degrees of severity. Our purposes were to identify the manifestations of hypermobility across multiple body systems and to study the recognition of hypermobility in the medical literature of multiple specialties over multiple decades. A literature search of the major medical disciplines for key words associated with HSD was performed. These specialties included gastroenterology, gynecology, neurology, psychiatry, oral-maxillofacial surgery, cardiology, and orthopaedic surgery. A specialty-specific impact factor (IF) score was calculated as the percentage of research articles that referenced hypermobility as a comorbidity over all articles within that specialty. Statistical differences were identified using single factor ANOVA with significance determined at p<0.05. We reviewed many published, specialty-specific manifestations of hypermobility, and describe them. All six non-orthopaedic specialties demonstrated a continually increasing relative IF ratio throughout the study period with a peak impact average of 0.22 (p<0.05 compared with other time ranges). There was a 93.3% overall increase in IF scores from the 1992–1998 period to the most recent period examined (p<0.05). Hypermobility is increasingly recognized as a significant health issue in multiple disciplines. Since dysplasia is associated with approximately 40% of all primary total hip arthroplasty cases, understanding the multi-system manifestations, and broad impact of hypermobility on patients, is relevant for every hip surgeon. We are expanding our research into other medical disciplines, including urology, ophthalmology, dermatology, clinical psychology, and others

Polymethylmethacrylate (PMMA) bone cement is strong in compression, however it tends to fail under torsion. Sufficient pressurisation and subsequent interdigitation between cement and bone are critical for the mechanical interlock of cemented orthopaedic implants, and an irregular surface on the acetabular cup is necessary for reasonable fixation at the cup-cement interface. There is limited literature investigating discrepancies in the failure mechanisms of cemented all-polyethylene acetabular cups with and without cement spacers, under torsional loading. In vitro experimental comparison of three groups of polyethylene acetabular prosthesis (PAP) cemented into prepared sawbone hemipelvises:. * PAP without PMMA spacers maintaining an equal cement mantle circumferentially. (Group 1 n=3). * PAP without PMMA spacers cemented deliberately ‘bottoming-out’ the implant within the acetabulum. (Group 2 n=3). * PAP with PMMA spacers. (Group 3 n=3). The constructs were tested to torstional failure on a custom designed setup, and statistical analysis done by a one-way ANOVA and Tukey-Welsh test. Group 3 demonstrated superior torsional resistance with a statistically significant torque of 145Nm (SD±12Nm) at failure, compared to group 2 (109Nm, SD±7Nm) and group 1 (99Nm, SD±8Nm). Group 3 experienced failure predominantly at the bone-cement interface, in contrast, Groups 1 and 2 exhibited failure predominantly at the cup-cement interface. There was no significant difference between Group 1 and 2. Qualitative analysis of the failure mode indicates the efficient redistribution of stress throughout the cement mantle, consistent with the greater uniformity of cement. PMMA spacers increase the resistance to torsional failure at the implant-cement interface. Acetabular components without spacers (Groups 1 and 2) failed at the implant-cement interface before the cement-bone interface, at a statistically significantly lower level of torque to failure. Although the PMMA spacers may reduce cement interdigitation at the cement-bone interface the torsional forces required to fail are likely supraphysiological

Chondral hip injuries are common secondary to femoroacetabular impingement (FAI). Treatment with arthroscopic procedures including chondroplasty and microfracture is becoming increasingly common but literature is limited to case series at specialist centres. The aim of this study is to compare outcomes of arthroscopic acetabular chondral procedures using the NAHR dataset (UK) which represents the largest series to date. All adult Arthroscopies recorded in the NAHR from Jan 2012 were available for inclusion. Exclusions included significant arthritis and femoral, complex or revision chondral procedures. Patients completed iHOT-12 & EQ-5D Index pre-operatively, 6 and 12 months. Data was analysed using T-test/ANOVA for between group/within group for continuous variables, chi square test for categorical variables and linear regression model for multivariable analysis. 5,752 patients, 60% female. 27% Chondroplasty, 5% Microfracture, 68% no Chondral Procedure. Maximum acetabular Outerbridge classification 14% Grade 1, 15% Grade 2, 17% Grade 3, 8% Grade 4, 9% no damage, not recorded in 37%. Higher proportion of Cam impingement in association with chondral treatments and a larger proportion of patients with no impingement recorded in group with no chondral procedures. There was a significant improvement versus baseline for all groups in iHOT-12 and EQ-5D Index (p<0.0001) including Grade four Outerbridge. There was significantly greater improvement in pre-operative scores in the chondroplasty group compared to the microfracture group at 6 and 12 months (p<0.05). Following hip arthroscopy, patients with chondral procedures experienced improved outcome scores despite Outerbridge 4 chondral damage. Presence of cam lesions are more commonly associated with chondral treatments. Good outcomes were maintained up to 12 months for chondral procedures, regardless of age or impingement pathology however pincers improved less and patients over 40 years took longer to see improvement

Hip fractures in elderly patients are managed at both major trauma centers (MTC) and trauma units (TU). Previous evidence has demonstrated the importance of early surgery to reduce the morbidity and mortality related to the injury. The aim of this study is to compare the ‘time to theatre' and ‘30 day mortality' in TUs versus MTC in UK. A retrospective review of prospectively collected data on NHFD was performed. The average ‘time to theatre' in hours and ‘30 day mortality' of all hospitals were analysed between January and December 2018. Further subgroup analysis was done to check for any regional variations; in each instance a Shapiro-Wilk test was used to check for normal distribution, followed by a one-way ANOVA with a Tukey's post hoc test. Data from 158 hospitals in England (ENG), Wales (WAL) and Northern Ireland (NI) were used; 18 of which were MTC. There were 57,936 operative cases in TUs and 8606 in MTC's. The mean time (hours) to surgery from presentation was 32.51 and 32.64 for TUs and MTC respectively (p=0.513). There was no significant difference in ‘30 day mortality' (p=0.635) between TUs (6%) and 5.7% MTC's (5.7%), MTC's and TUs in ENG, WAL and NI (p=0.555), and MTC and WAL, NI and the different regions of ENG (p=0.209). A significant difference was observed, between the regional practice for TUs versus MTC's in ENG, WAL and NI (p=0.001) and between MTC's and TUs in WAL, NI and the different regions of ENG (p=0.001), with patients waiting significantly longer in NI for their procedure (mean=60.25 hours, p=0.001). There was no significant difference in time to surgery or 30 day mortality between TUs and MTC's, demonstrating comparable hip fracture care, despite MTCs need to prioritise more serious injuries

Purpose. To determine the differences of biomechanical properties in three conditions including 1) native cam deformity 2) cam deformity with incomplete resection and 3) cam deformity with complete resection. Methods. A cadaveric study was performed using 8 frozen, hemi-pelvises with cam-type deformity (alpha angle >55°) measured on CT scan and an intact labrum. Intraarticular pressure maps were produced for each specimen under the following conditions: 1) native cam deformity, 2) cam deformity with incomplete resection and 3) cam deformity with complete resection. A 5.5-mm burr was used to resect the lateral portion of the cam deformity to a depth of 3–4 mm. The specimen was placed in a custom designed jig in the MTS electromechanical test system to create pressure and area map measurements. In each condition, three biomechanical parameters were obtained including contact pressure, contact area and peak force within a region-of-interest (ROI). Repeated measurements were performed for three times in each condition and the average value of each parameter was used for statistical analysis. ANOVA was used to compare biomechanical parameters between three conditions. Results. Repeated measures ANOVA analysis demonstrated that the pressures averages of hips with complete resection of cam lesions were significantly lower when compared to averages of hips with incomplete femoral cam lesion and intact cam deformity (2.48. +. 0.56 kg/cm. 3. vs 2.32. +. 0.50 kg/cm. 3. vs 2.02. +. 0.54 kg/cm. 3. , respectively; p-value=0.01). Percentage reduction of contact pressure in the complete resection and incomplete resection groups compared to the native CAM deformity groups were 18.49% and 1.58% respectively. There was no statistically significant difference in contact pressures between the incomplete resection and unoperated groups. Contact area and peak force showed no statistically significant differences across three conditions. Conclusion. There are lower intraarticular hip contract pressures in complete resection of the cam lesions when compared to an incomplete resection and intact hip without resection. These observations underscore the importance of ensuring complete resection of femoral cam lesions in patients undergoing hip arthroscopy for femoroacetabular impingement syndrome. For any tables or figures, please contact the authors directly

Polymethylmethacetate (PMMA) is a bone cement used in over 725,000 primary hip arthroplasties in 2018. Cement integrity is affected by external factors, including temperature, mixing technique and moisture uptake, which can influence cement microstructure. Changes in the cement microstructure may ultimately threaten the survivorship of the implant. The introduction of enhanced recovery and various local anaesthetic infiltration techniques have been adopted in an attempt to facilitate early mobilisation and reduce length of stay. Our study aims to investigate if the mechanical properties of PMMA are altered with exposure to Ropivacaine LA. Cements were cured in three separate states (air, serum and serum with LA) and the mechanical properties tested at 24 hours and 28 days. Using Refobacin bone cement provided by ZimmerBIOMET, cylindrical molds (12×6mm) were constructed with a split-mold. The LA used was 2mg/ml Ropivacaine hydrochloride solution. Using pilot data, this study was powered to 80% and a sample size of 10 per group (n=60) was calculated. Cement samples were subjected to compressive loading using a universal testing apparatus (Zwick/Roell). Yield-strength and modulus values were extracted from the respective stress versus strain curves. Significant differences were determined by one-way anova for each time point, and Bonferroni post-hoc testing to determine significance between actual groups. At 24-hours there were no significant differences in strength or modulus between groups. At 28-day strength and modulus increased in all groups. Compared to the air group, both serum and LA groups show a significant decrease in compressive strength. The modulus for the LA group is significantly less stiff compared to the air group. The results suggest that the initial exposure to LA has a significant impact on the physical properties of the PMMA. We propose increased awareness of the potential effects this may have on the longevity and survivorship of cemented implants

Aims

The aim of the study was to investigate whether the primary stability of press-fit acetabular components can be improved by altering the impaction procedure.

Introduction. We studied free (= local powder) tobramycin and doxycycline, and controlled release (= local lipid bilayer) doxycycline formulations in a rat model representing a generic joint infection. We . hypothesized. that evidence of infection (quantitative colony forming units (CFU), qualitative SEM, histopathology) (1a) would be reduced with local vs. systemic antibiotic, (1b) any antibiotic would be superior to control (2) there would be a difference among antibiotics, and (3) antibiotic would not be detectable in serum at 4-week euthanasia. Methods. Study groups. included infected and non-infected (1) control, (2) systemic ceftriaxone (daily), (3) local tobramycin, (4) local doxycycline and (5) controlled release doxycycline. With IACUC approval, (10 rats/group; power =0.8), 50-μl, 10×4 CFU Staphylococcus aureus, slowly injecting into distal femoral medullary canal, reliably created joint infection. Antibiotic formulation was introduced locally into cavity and joint, pin was inserted, and tissues closed. After 4-weeks, serum, pin, bone and synovium were obtained. CFU/ml of bone and synovium were quantified using macrotiter method. SEM imaged biofilm on surface of pin, histopathology identified tissue response, liquid chromatography/mass spectrometry measured plasma antibiotic. Kruskal-Wallis one-way ANOVA compared groups. Results. Groups receiving antibiotic reported lower CFU/ml in synovium compared with control (no treatment) group (1b), but there was no difference between systemic, free or controlled antibiotics (1a). Different results with different antibiotics were shown, with free tobramycin reducing CFU/ml to a greater extent than free doxycycline in the synovium (2) (p<0.05). Antibiotic in plasma was nondetectable all groups (3). SEM revealed some biofilm on pin in all groups. . Limitations. include inoculation method, single observation period, administration of only one bacterial and antibiotic dose, and not including pairing local and systemic antibiotic. Conclusion. There was no difference in infection reduction nor detectable antibiotic in serum for any antibiotic formulation, but CFU's in synovium differed based on antibiotic formulation. For any tables or figures, please contact the authors directly

Aims

The risk factors for abnormal spinopelvic mobility (SPM), defined as an anterior rotation of the spinopelvic tilt (∆SPT) ≥ 20° in a flexed-seated position, have been described. The implication of pelvic incidence (PI) is unclear, and the concept of lumbar lordosis (LL) based on anatomical limits may be erroneous. The distribution of LL, including a unusual shape in patients with a high lordosis, a low pelvic incidence, and an anteverted pelvis seems more relevant.

Aims

Refobacin Bone Cement R and Palacos R + G bone cement were introduced to replace the original cement Refobacin Palacos R in 2005. Both cements were assumed to behave in a biomechanically similar fashion to the original cement. The primary aim of this study was to compare the migration of a polished triple-tapered femoral stem fixed with either Refobacin Bone Cement R or Palacos R + G bone cement. Repeated radiostereometric analysis was used to measure migration of the femoral head centre. The secondary aims were evaluation of cement mantle, stem positioning, and patient-reported outcome measures.

Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

Aims

The frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes.

Aims

The aim of this study was to explore the relationship between reason for revision total hip arthroplasty (rTHA) and outcomes in terms of patient-reported outcome measures (PROMs).

Aims

The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance.

Aims

Pelvic incidence (PI) is considered an important anatomical parameter for determining the sagittal balance of the spine. The contribution of an abnormal PI to hip osteoarthritis (OA) remains controversial. In this study, we aimed to investigate the relationship between PI and hip OA, and the difference in PI between hip OA without anatomical abnormalities (primary OA) and hip OA with developmental dysplasia of the hip (DDH-OA).

Aims

The effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?

Introduction. Training the next generation of surgeon's forms part of routine Consultant practice. Stress causes activation of the Autonomic Nervous System and this can be directly measured using heart rate (HR). Training time is limited with pressures from EWTD and management and efficiency targets. The aim of this study was to assess whether being an orthopaedic trainer is more stressful than performing the surgery. Methodology. This was a prospective multicentre study. Consultant orthopaedic surgeon HR was monitored intra-operatively using a ‘Wahoo Fitness’ chest strap and the data recorded by the proprietary Android app. Data was collected prior to surgery to obtain a resting heart rate, and at set points during total hip arthroplasty (THA) and total knee arthroplasty (TKA). The peak and mean HR for each stage of the operation were recorded and compared to cases where the consultant surgeon was performing the case or assisting a trainee. Data was compared with a 2-way ANOVA with repeated measures. Results. 23 cases (13 THA, trainer operating in 3 and 10 TKR, trainer operating in 2). The average baseline HR during the procedure was significantly higher when the consultant surgeon was performing the procedure when compared to training a trainee. There were spikes in consultant HR at insertion of both acetabulum and femur during THA, during component trailing and insertion during TKA. These spikes were lower when training than when performing. Discussion. The average HR is lower and the increase in HR at key stages of THA and TKA is less when training than when performing. Although difficult to disentangle the contribution of physical exertion from stress, the lower HR may indicate lower stress, and given stress can significantly shorten your life expectancy – having and training a trainee could seriously help prolong your life and career

Aims

Hip arthroplasty does not always restore normal anatomy. This is due to inaccurate surgery or lack of stem sizes. We evaluated the aptitude of four total hip arthroplasty systems to restore an anatomical and medialized hip rotation centre.