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Introduction
Acetabular and spino-pelvic (SP) morphological parameters are important determinants of hip joint dynamics. This study aims to determine whether acetabular and SP morphological differences exist between hips with and without cam morphology and between symptomatic and asymptomatic hips with cam morphology.
Patients/Materials & Methods
A prospective cohort of 67 patients/hips was studied. Hips were either asymptomatic with no cam (Controls, n=18), symptomatic with cam (n=26) or asymptomatic with cam (n=23). CT-based quantitative assessments of femoral, acetabular, pelvic and spino-pelvic parameters were performed. Measurements were compared between controls and those with a cam deformity, as well as between the 3 groups. Morphological parameters that were independent predictors of a symptomatic Cam were determined using a regression analysis.
Introduction
Femoroacetabular impingement (FAI) is a morphological hip joint deformity associated with pain and early degenerative changes. Cam-type FAI is prevalent in young male athletes. While biomechanical deficiencies (decreased hip muscle strength and range of motion (ROM)) have been associated with symptomatic cam-type FAI (sFAI), results have been conflicting and little is known about biomechanical characteristics during dynamic tasks.
Objectives
(1) Compare coronal-plane hip muscle strength, activation and joint rotation during movement tasks in sFAI hips against healthy controls. (2) Investigate the effect of hip internal rotation ROM (IR-ROM) on these outcomes.
Introduction
Open hip debridement surgery has been used for treatment of femoral acetabular impingement pain for over ten years in our unit. While literature has reported promising short-term outcomes, longer term outcomes are more sparsely reported.
Patients/Materials & Methods
Patients who had undergone this surgery were identified on our database. Electronic, radiographic and paper records were reviewed. Demographic data, radiological and operative findings were recorded. Patients underwent ten-year review with standardised AP hip radiographs, questionnaire, non-arthritic hip (NAHS), Oxford hip (OHS) and SF-12 scores
Purpose
Femoroacetabular impingement syndrome (FAI) is a common cause of hip and groin pain in young adults. Physiotherapy and surgery have both been used to treat FAI syndrome, but there is no robust evidence of comparative effectiveness. UK FASHIoN compared the clinical and cost-effectiveness of arthroscopic hip surgery (HA) versus best conservative care in patients with FAI syndrome.
Methods
UK FASHIoN was a pragmatic, multicentre, 2 parallel arm, superiority, randomised controlled trial in patients with FAI syndrome. Eligible patients were over 16 without radiographic signs of osteoarthritis, deemed suitable for arthroscopic FAI surgery. Participants were randomly allocated to HA or Personalised Hip Therapy (PHT - a physiotherapist-led programme comprising 6 to 10 sessions). The primary outcome measure was hip-related quality of life using the patient-reported International Hip Outcome Tool (iHOT-33) at 12 months. Secondary outcomes included EQ5D5L, SF12, adverse events, and cost-effectiveness. Primary analysis compared differences in iHOT-33 scores at 12 months by intention to treat.
We have investigated whether the pattern of subchondral acetabular cyst formation reflects hip pathology and may provide a prognostic indicator for treatment.
A single surgeon series of sequential hip arthroscopies was reviewed to identify the most recent 200 cases undertaken on a previously un-operated joint with pre-operative plain radiographs and computed tomography or magnetic resonance scan available for review. Also, serial “non-arthritic hip scores” (NAHS) recorded pre-operatively, at 6 weeks and 3 months post-surgery. The acetabular Lateral Centre Edge Angle, the Acetabular Index, the FEAR index and the Kallgren and Lawrence grade were determined. All images were reviewed by two independent assessors and divided into four groups according to acetabular subchondral cyst distribution.
No association was identified between gender and patient reported outcomes.
SDC patients were significantly younger than the other three groups (p <0.001). At three months after surgery, the average increase of the NAHS in the four groups was 25.3, 23.5, 4.2 and 4.9 respectively. Acetabular dysplasia was identified in 72% of the SDC group compared to 18%, 16% and 33% in NC, SPC and MC groups. Degenerative change was identified in 86% of the MC group compared to 18%, 40% and 41% of the NC, SPC and SDC groups.
The early patient reported outcome following hip arthroscopy was significantly affected by the location and number of acetabular subchondral cysts. A Solitary Dome Cyst is indicative of underling hip dysplasia. Multiple Cysts are indicative of degenerative disease. The majority of patients in these groups have poor three-month outcomes after hip arthroscopy.
Introduction
Decreases in trainees' working hours, coupled with evidence of worse outcomes when hip arthroscopies are performed by inexperienced surgeons, mandate the development of additional means of arthroscopic training. Though virtual reality simulation training has been adopted by other surgical specialities, its slow uptake in arthroscopic training is due to a lack of evidence as to its benefits. These benefits can be demonstrated through learning curves associated with simulator training – with practice reflecting measurable increases in validated performance metrics.
Materials & Methods
Twenty-five medical students completed seven simulated arthroscopies of a healthy virtual hip joint in the supine position on a simulator previously shown to have construct validity. Twelve targets had to be visualised within the central compartment; six via the anterior portal, three via the anterolateral portal and three via the posterolateral portal. Eight students proceeded to complete seven probe examinations of a healthy virtual hip joint. Eight targets were probed via the anterolateral portal. Task duration, number of collisions with soft tissue and bone, and distance travelled by arthroscope were measured by the simulator for every session.
Introduction
Acetabular dysplasia is associated with an increased risk of hip pain and early development of osteoarthritis (OA). The Bernese peri-acetabular osteotomy (PAO) is the most well-established technique in the Western world for the treatment of symptomatic acetabular dysplasia. This case-control study aims to assess whether the severity of acetabular dysplasia has an effect on outcome following Peri-Acetabular Osteotomy (PAO) and/or the ability to achieve desired acetabular correction.
Patients/Materials & Methods
A prospective, multicentre, longitudinal cohort of consecutive PAOs was reviewed. Of the available 381 cases, 61 hips had pre-PAO radiographic features of lesser-dysplasia [Acetabular-Index (AI)<15° and Lateral-Centre-Edge-Angle (LCEA)>15°) and comprised the ‘study-group’. ‘Study-Group’ was matched for all factors known to influence outcome post-PAO [age, gender, BMI, Tönnis-grade and joint congruency (p=0.6–0.9)] with a ‘Comparison-Group’ of pronounced dysplasia (n=183). Clinical outcomes, complications and the ability to achieve optimum correction (LCEA: 25°–40°/AI: 0°–+10°) were compared.
Introduction
Patients with pre-existing dementia are more susceptible to hip fracture due to various risk factors such as age, decreased activity leading to sarcopenia and osteoporosis, Vitamin D deficiency and presence of Apolipoprotein gene. The mortality associated with dementia and fracture neck of femurs was thought to be 2.3 times more than that of patients with intact cognitive function. The aim of this study is to assess the mortality of patients at 28 days, 4 months and one year after undergoing surgery for fracture neck of femurs.
Methods
A retrospective study of 184 patients admitted with fracture neck of femur and had dementia for a period from April 2014 to August 2016 were carried out. The patient demographics, AMT score, pre-operative co-morbidities, perioperative mortality and one year mortality were analysed.
Aim
Left sided hip fractures are more common but no obvious cause has been identified. Left handedness has previously been associated with an increased risk of fracture for a number of sites but to the best of our knowledge no association between handedness and hip fracture has previously been reported.
Methods
2 separate 6-month prospective reviews of hip fracture patients aged over 65 years-of-age were conducted at 2 different hospitals. Handedness was dete2rmined at the time of admission. The second review focused on the use of walking aids. Patients with a previous cerebrovascular accident, neurological condition or contralateral hip prosthesis were excluded due to increased balance problems and falls risk.
Background
This clinical study aims to establish the rate of operative inadvertent hypothermia (IH) in elderly hip fracture patients (>65 years old). We postulate that differences exist in risk factors and hypothesised poorer outcomes in patients with IH.
Methods
A single centre, retrospective study of 929 hip fracture patients managed operatively between June 2015 and July 2017 was conducted. Patients’ demographic, anaesthetic and surgical variables were analysed together with outcomes for length of stay (LOS), 30-day re-admissions, and 30-day mortality.
Background
Isolated fracture of the greater trochanter is an uncommon presentation of hip fracture. Traditional teaching has been to manage these injuries nonoperatively, but modern imaging techniques have made it possible to detect occult intertrochanteric extension of the fracture in up to 90% of cases.
This study aims to review the investigation and management of greater trochanter fractures in a single major trauma centre.
Methods
A retrospective review was completed of patients admitted with greater trochanter fractures. These were matched to cases with 2-part extracapsular fractures. Initial management and clinical outcome was established using electronic notes and radiographs. Mortality and length of stay was calculated for both groups.
Fractured neck of femur is a significant health concern within the UK. NICE guidance on the management of displaced intracapsular fractures states that total hip arthroplasty should be offered when patients can; walk independently out of doors with no more than a stick, not cognitively impaired, medically fit for anaesthesia and the procedure. We previously managed this subgroup using THA with standard sockets. Following an audit of this practice a dislocation rate of 9% was identified and practice was changed to using dual mobility (THA-DM) with the theoretical advantage of reducing dislocation.
We reviewed all patients who underwent THA for fracture using Bluespier from 2013–2017. Operative notes and radiographs were reviewed to ensure the patients had undergone THA for displaced intracapsular fracture. Basic patient demographics were collected. Our primary outcome was dislocation rates at one year. Our secondary outcomes were length of time to surgery, length of stay, operative time, mortality, return to theatre rates and one year Oxford hip scores
We found a control group of 45 THA procedures and a dual mobility group of 143 procedures. The one year dislocation rate from the THA-SS group was 9% and the THA-DM group was 1.4%(CI±1.9%)(p=<0.05%). There were also non-significant reductions in time to surgery, length of stay, operative time, mortality, return to theatre rates. The one year Oxford hip score was comparable at 42.2 to 41.8.
This study demonstrates a significant reduction in one year dislocation rates with comparable oxford hip scores. Use of THA-DM should be considered in those patients who meet NICE criteria. Further research is needed into long term dislocation rates.
Total Hip Replacement (THR) is widely assumed to resolve sleep disturbance commonly experienced by individuals with hip osteoarthritis (OA). We report a study of 329 THRs with mean age of 71.9 years comparing pre-operative and one and two year post-operative patient reported outcomes for sleep disturbance to determine the veracity of this expectation. Data was collected from the validated Oxford Hip Patient Reported Questionnaire. Specifically, Question 12: “During the past four weeks, have you been troubled by pain from your hip in bed at night?” Answers to the question were multiple choice: No nights (4 points), Only 1 or 2 nights (3 points), Some nights (2 points), Most nights (1 point) and Every Night (0 points)
Pre-operatively, the mean score for patients with hip OA was 1.2/4. This increased to 3.5 at one year and was also maintained at two years. The pre- to post-operative improvement was significant at both one and two years for THR with p <0.00001. Pre-operatively, only 6% of patients with arthritic hips reported that they were never woken from sleep because of their painful hip. One year after THR 72% always enjoyed pain free sleeping and at two years this had risen to 75%. When patients who only experienced disturbance one or two nights per month were included, the three figures increased from 13% to 83% and 83% respectively.
The study confirms that sleep disturbance affects over 90% of patients with arthritic hip joints. Over 80% of THR patients will enjoy sleep that is seldom or never disturbed by their artificial hip. The improvement achieved by THR occurs within a year of surgery and is preserved at two years. In this regard, hip replacement is a highly effective intervention.
Introduction
The Best Practice Tariff (BpT) for primary THR / TKR was established in 2014 and rewards good clinical practice with a £550 uplift on the £5000 basic reimbursement. For an ‘average unit’ performing 220 primary THR and 260 eligible knee surgeries (NJR data) this equates to £265,000 per year or over £1million since its inception. The aim of this study was to investigate why Chelsea & Westminster Hospital NHS Trust was not receiving this reimbursement.
Materials & Methods
BpT is dependent on four factors (NHS England, PROMS): (i) the provider not having an average health gain significantly below the national average, (ii) a minimum National Joint Registry compliance rate of 85%, (iii) an NJR unknown consent rate below 15%, and (iv) a PROMs participation rate of 50%.
Aims
Thromboprophylaxis following Total Hip Replacement (THR) surgery remains controversial, balancing VTE prevention against wound leakage and subsequent deep infection.
We analysed the 90 day cause of death post THR in our institution after the implementation of new thromboprophylactic policy of low dose aspirin for low risk patients, as part of a multimodal regime. Those at high risk were anticoagulated.
Patients and methods
The PAS database was used to identify patients undergoing primary THR between January 2012 and June 2017 at The Royal Derby Hospital, and all deaths within 90 days. Trauma cases were excluded. Case note review and Coroner's verdict were utilised to ascertain cause of death. Results were compared to a previous study at the same institution prior to the introduction of the new policy, where thromboprophylaxis was decided upon by surgeon preference for either LMWH, aspirin or warfarin.
Introduction
Patient related outcome measures (PROMS) are now routinely undertaken in patients undergoing hip arthroplasty. These are in the form of the Oxford Hip Score (OHS) and EQ5D questionnaires pre-operation and at 6 months' post operation. MYMOPS is a patient specific outcome measure that allows patients to list their individualised symptoms and activities that are limited and is used is other medical specialities but not currently within orthopaedic surgery. The aim of this study was to validate the MYMOPS questionnaire for use in hip arthroplasty by comparing it to the OHS.
Patients/Materials & Methods
At a single centre, 50 patients were recruited to our prospective trial after ethical approval. A MYMOPS questionnaire and an OHS was filled in pre-operation and then at 6 months post-operatively. 6 patients filled in either form incorrectly and were excluded. The remaining 44 included 30 females and 14 males with an average age of 68.5 (range 35–90).
Introduction
Proximal short stems have gained in popularity for perceived bone preservation but more recently, physiological loading. We report the medium term success of a calcar loading, short stem in a large cohort from a single unit with multiple surgeons.
Patients/Materials & Methods
Prospectively collected sequential data, with no loss to follow-up, was retrospectively analysed from our own local database. Demographic data was assimilated to collect age, sex, BMI smoking history. Revision cases were analysed for cause and a PTIR and Kaplan Meier Curve constructed to quantify survival. Radiographs reviewed in 100 of the oldest (2009 to 2011) cases to look specifically for calcar resorption and stem sink. Imatri software was used for calculations: sink was categorised into greater or less than 0.5cm; calcar resorption was estimated using maximal osteotomy surface change of slope. Patient pre-operative and post-operative outcome scores (using Harris Hip, Charnley and Oxford scales) were extracted from the database.
Introduction/Aims
The Exeter Stem can be used with metal femoral head that are made of either cobalt chrome, or stainless steel. The aim of this study was to compare the rates of revision of these two metal femoral head types when used with this femoral component.
Method
Australian Orthopaedic Association National Joint Replacement Registry (AOANJRR) Data from September 1999 until December 2015 for all primary THRs using an Exeter or an Exeter v40 stem with the diagnosis of osteoarthritis were analysed. Only bearing couples that used a metal head with polyethylene were included. The cumulative percent revision (CPR) calculated using Kaplan-Meier estimates were compared for the two metal head types. CPR were further analysed by age, polyethylene type and head size. Reasons for revision and types of revision were assessed.
Introduction
Radiological inclination (RI) is determined in part by operative inclination (OI), which is defined as the angle between the cup axis or handle and the sagittal plane. In lateral decubitus the theatre floor becomes a surrogate for the pelvic sagittal plane.
Critically at the time of cup insertion if the pelvic sagittal plane is not parallel to the floor either because the upper hemi pelvis is internally rotated or adducted, RI can be much greater than expected. We have developed a simple Pelvic Orientation Device (POD) to help achieve a horizontal pelvic sagittal plane.
The POD is a 3-sided square with flat footplates that are placed against the patient's posterior superior iliac spines following initial positioning (figure 1). A digital inclinometer is then placed parallel and perpendicular to the patient to give readings of internal rotation and adduction, which can then be corrected.
Methods
A model representing the posterior aspect of the pelvis was created. This permitted known movement in two planes to simulate internal rotation and adduction of the upper hemi pelvis, with 15 known pre-set positions. 20 participants tested the POD in 5 random, blinded position combinations, providing 200 readings.
The accuracy was measured by subtracting each reading from the known value.
Introduction
The resultant cup orientation depends upon the orientation of the pelvis at impaction. No studies to date have assessed whether patient-position during total hip arthroplasty (THA) has an effect on cup orientation. This study aims to 1) Determine the difference in pelvic position that occurs between surgery and radiographic, supine, post-operative assessment; 2) Examine how the difference in pelvic position influences subsequent cup orientation and 3) Establish whether pelvic orientation, and thereafter cup orientation, differences exist between THAs performed in the supine versus the lateral decubitus positions.
Patients/Materials & Methods
This is a retrospective, multi-surgeon, single-centre, consecutive series. 321 THAs who had intra-operative, post-cup impaction, AP pelvic radiograph, in the operative position were included; 167 were performed with the patient supine (anterior approach), whilst 154 were performed in the lateral decubitus (posterior approach). Cup inclination/anteversion was measured from intra- and post-operative radiographs and the difference (Δ) was determined. Change in pelvic position (tilt, rotation, obliquity) between surgery and post-operatively was calculated from Δinclination/anteversion using the Levenberg-Marquardt algorithm.
Introduction
The mechanisms of how spinal arthrodesis (SA) affects patient function after total hip replacement (THA) remain unclear. The objectives of this study were to a) Determine how outcome post-THA compares between patients with- and without-SA, b) Characterize sagittal pelvic changes that occur when moving between different functional positions, and test for differences between patients with- and without-SA, and c) Assess whether differences in sagittal pelvic dynamics are associated with outcome post-THA.
Patients/Materials & Methods
Forty-two patients with THA-SA (60 hips) were case-control matched for age, gender, BMI with 42 THA-only patients (60 hips). All presented for review where outcome, PROMs [including Oxford-Hip-Score(OHS)] and 4 radiographs of the pelvis and spino-pelvic complex in 3 positions (supine, standing, deep-seated) were obtained. Cup orientation and various spino-pelvic parameters [including pelvic tilt (PT) and Pelvic-Femoral-Angle (PFA)] were measured. The difference in PT between standing and seated allowed for patient classification based on spino-pelvic mobility into normal (±10–30°), stiff (<±10°) or hypermobile (>±30°).
Introduction
Registry data from around the world demonstrates instability following primary THA is a leading indication for revision. However, the burden of THA dislocation is poorly documented and is not routinely recorded or reported at a national level. Our aim was to determine the rate of dislocation following primary THA in contemporary practice and in doing so determining the burden of THA dislocation to the NHS in Wales.
Method
We considered all Welsh residents who underwent primary THA from 2011–2016. Via clinical coding linkage using Patient Episode Database for Wales (PEDW), the equivalent of HES data in England, we were able determine re-admission for dislocation, revision THA following dislocation and all cause revision at 1 to 5 years follow-up.
Since the introduction of national guidelines in 2009 encouraging the use of total hip arthroplasty (THA) to treat intracapsular neck of femur fractures there has been no population-based studies into the surgical outcomes for this indication. This study aims to calculate the complication rates for THA when performed for a fractured neck of femur and compare them to THA performed for primary osteoarthritis in the same population.
The Scottish Arthroplasty Project was used to identify all THAs performed in Scotland for neck of femur fracture and osteoarthritis between 1st of January 2009 and 31st December 2014. Dislocation, infection and revision rates at 1 year were calculated.
The rate of dislocation, infection and revision at 1 year were all significantly increased among the fracture neck of femur cohort. In total 44046 THAs were performed, 38316 for OA and 2715 for a neck of femur fracture. 2.1% of patients (n=57) who underwent a THA for a neck of femur fracture suffered a dislocation in the 1st year postoperatively, compared to 0.9% (n=337) when the THA was performed for osteoarthritis. Relative Risk of dislocation: 2.3870 (95% C.I. 1.8077–3.1252, p value <0.0001). Relative Risk of infection: 1.4561 (95% C.I. 1.0496–2.0200, p value 0.0245) Relative Risk of revision: 1.4807 (95% C.I. 1.0308–2.1268, p value 0.0336).
This is the first time a dislocation rate for THA performed for a neck of femur fracture has been calculated for an entire population. As the number of THAs for neck of femur fracture increases this dislocation rate will have clinical implications.
Introduction
Heterotopic Ossification(HO) is a recognized complication following Total Hip Arthroplasty(THA) that can compromise patient outcomes. Our objectives were to report its incidence and risk factors in a modern arthroplasty unit(MAU).
Methods
2305 consecutive primary THAs in 2150 patients(887♂;1263♀) undertaken at a single centre and followed-up for at least one year constituted the study cohort. A retrospective review of patient demographics (age, side, body mass index[BMI], type of anaesthesia, surgical approach, method of fixation, estimated blood loss[EBL] and operative time), serial radiographs and outcome measure (The Oxford hip score[OHS]) were undertaken. All HO were further followed for additional four years to determine the incidence of Revision THA at five years. Descriptive statistics and logistic regression was undertaken to identify the risk factors for HO using Statistical Package(SPSS) version16.
Introduction
This study aims to determine how the acetabular version changes during the key developmental stage of adolescence, and what contributes to this change. In addition, we examined whether patient factors (BMI, activity levels) or the femoral-sided anatomy contribute to any observed changes.
Patients/Materials & Methods
This prospective longitudinal cohort study included 19 volunteers (38 healthy hips). The participants underwent clinical examination (BMI, range of movement assessment), MRIs of both hips at recruitment and at follow-up (6 ± 2 years) and HSS Paediatric Functional Activity Brief Scale (Pedi-FABS) questionnaire. MRI scans were assessed at both time points to determine change of the tri-radiate cartilage complex (TCC), the acetabular anteversion, the degree of anterior, posterior, and superior femoral head coverage by the acetabulum, and anterior and antero-superior alpha angles. We investigated if the change in anteversion and sector angles was influenced by the BMI, range of movement measurements, the Pedi-FABS or the alpha angle measurements.
Background
Heterotopic ossification (HO) is lamellar bone formation in the soft tissues following trauma or joint replacement for osteoarthritis (OA). A genome wide association study of HO patients after total hip arthroplasty for OA has identified Kinesin Family Member 26B (KIF26B) as a gene associated with HO severity. KIF26B has previously been associated with HO in mice.
Hypothesis and aims: We hypothesised that Kif26b regulates the osteogenic trans-differentiation of myoblasts; a possible mechanism of HO. Using an
Methods
We developed CRISPR/Cas9 mediated Kif26b knockout (KO) C2C12 myoblasts. Wild type (WT) and KO cells were transdifferentiated towards an osteogenic lineage using BMP-2 for 24 days. The effect of Kif26b KO on mineralisation was quantified by calcium staining. The mean difference (±SEM) in gene expression between WT and KO lines was compared with ANOVA.
Introduction
The changes in sagittal spino-pelvic balance from standing to sitting in patients with end-stage osteoarthritis (OA) of the hip remain poorly characterized. Our aim was to 1) investigate the contribution of sagittal spino-pelvic movement and hip flexion when moving from a standing to sitting posture in patients with hip OA; 2) determine the proportion of OA-patients with stiff, normal or hypermobile spino-pelvic mobility and 3) identify radiographic parameters correlating with spino-pelvic mobility.
Methods
This prospective diagnostic cohort study followed 116 consecutive patients with end-stage osteoarthritis awaiting THR. All patients underwent preoperative standardized radiographs (lateral view) of the lumbar spine, pelvis and proximal femur using EOS© in standing position and with femurs parallel to the floor in order to achieve a 90°-seated position. Radiographic measurements performed included lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), pelvic incidence (PI) and pelvic-femoral-angle (PFA). The difference in PT between standing and seated allowed for patient classification based on spino-pelvic mobility into stiff (<±10°), normal (±10–30°), or hypermobile (>±30°).
Introduction
Periprosthetic osteolysis resulting in aseptic loosening is a leading cause for total hip arthroplasty (THA) failure. Individuals vary in their susceptibility to osteolysis, and it is thought that heritable factors contribute to this variation. We conducted two genome-wide association studies to identify genetic risk loci associated with osteolysis and genetic risk loci associated with time to prosthesis failure due to osteolysis.
Patients/Materials & Methods
The Norway cohort comprised 2,624 subjects after THA recruited from the Norwegian Arthroplasty Registry, 779 with revision surgery for osteolysis. The UK cohort comprised 890 subjects recruited from hospitals in the north of England, 317 with radiographic evidence or revision surgery for osteolysis. All subjects had received a fully cemented or hybrid THA using small-diameter metal or ceramic-on-conventional polyethylene bearing. Osteolysis susceptibility case-control analyses and quantitative trait analyses for time to prosthesis failure were undertaken after genome-wide genotyping. Finally, a meta-analysis of the discovery datasets was undertaken.
Introduction
Numerous studies have reported on clinically significant volumes of material loss and corrosion at the head-stem junction of metal-on-metal (MOM) hips; less is understood about metal-on-polyethylene (MOP) hips. We compared the effect of bearing type (MOM vs MOP) on taper material loss for a hip system of a single design (DePuy Pinnacle).
Methods
We recruited retrieved MOM (n=30) and MOP (n=22) bearing hips that were consecutively received at our centre.
We prospectively collected associated clinical and imaging data. We measured the severity of corrosion and volumes of material loss at each head taper surface and used multivariate statistical analysis to investigate differences between the two bearing types.
Background
There has been a trend in the evolution of total hip arthroplasty towards increased modularity, with this increase in modularity come some potentially harmful consequences. Modularity at the neck shaft junction has been linked to corrosion, adverse reaction to metal debris and pseudotumor formation.
The aim of this retrieval study is to assess whether the surface integrity of the polyethylene (PE) liner is affected by metal wear debris in a single implant design series of THA revised for trunnionosis.
Method
A retrieval analysis of thirty dual-taper modular neck hip prostheses was performed, the mean time from implantation to revision was 2.7 years (1.02–6.2). The PE liners were analysed using a scanning electron microscope with an energy dispersive spectrometer to assess for metal particles embedded on the liner surface. Serum metal ion levels and inflammatory markers were also analysed.
Introduction
The development of an algorithm that provides accurate individualised estimates of revision risk could help patients make informed surgical treatment choices. This requires building a survival model based on fixed and modifiable risk factors that predict outcome at the individual level. Here we compare different survival models for predicting prosthesis survivorship after hip replacement for osteoarthritis using data from the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man (NJR).
Methods
In this comparative study we implemented parametric and flexible parametric (FP) methods and random survival forests (RSF). The overall performance of the parametric models was compared using Akaike information criterion (AIC). The preferred parametric model and the RSF algorithm were further compared in terms of the Brier score, concordance index and calibration via repeated five-fold cross-validation.
Introduction
Fluorodeoxuglucose(FDG) Positron Emission Tomography(PET) scan is used in the diagnosis of prosthetic joint infection, when the inflammatory markers and aspiration of the joint do not establish a definitive diagnosis. The aim of our study was to analyse the utility of FDG PET scan in decision making in these patients.
Methods
We performed a prospective study of patients who underwent a FDG PET scan for suspected prosthetic hip infection, between September 2013 and July 2017. We analysed the results of aspiration, culture and sensitivity, histology of intra-operative samples and inflammatory markers. Our gold standard for diagnosis of infection was 3 or more positive cultures of the same organism. Diagnostic utility statistics for FDG PET were performed.
Introduction
Periprosthetic joint infection (PJI) can be difficult to diagnose. A variety of techniques have been described. The efficacy of the alpha-defensin laboratory test was examined and compared with other established modalities in the diagnostic workup of ‘real world’ arthroplasty patients.
Methods
This was a retrospective review of 210 episodes (86 hips, 124 Knees) in 172 patients at one centre, and included samples from acute admissions, elective aspirations, and planned revisions. MSIS (musculoskeletal infection society) major and minor criteria were used for diagnosing PJI.
Each patient was investigated using a standardised protocol with inflammatory markers, synovial fluid analysis for white cell count (SWCC) and polymorphonuclear leukoctyes percentage (PMN %), and synovial fluid/tissue culture. Synovial fluid was also tested for alpha-defensin.
Cement-in-cement femoral revision is a proven technique in revision total hip arthroplasty, with excellent results when using standard sized Exeter stems. The Exeter 44/00 125 mm short revision stem was introduced in 2004 to facilitate cement-in-cement revision. The stem is 25mm shorter and has a slimmer body to allow greater flexibility to adjust depth of insertion and version of the stem. However, it is not known if this change in stem length and size effects its longer term performance. We therefore reviewed the clinical outcome and survival of the Exeter 44/00 short stem used for cement-in-cement revision in our unit, with a minimum of 5 years follow up.
166 cases were performed between 2004 and 2010. 103 hips were available for 5 year clinical and radiological follow up, with 91 hips surviving to final review in 2017. At 5 years, 43 hips had died, 13 were revised and 7 were too frail to attend clinical review. The fate of all 166 hips were known and included in the survival analysis.
Median clinical scores improved significantly. Sixteen hips required re-revision (infection 6, loose cup 3, periprosthetic fracture 3, instability 2, stem fracture with chronic infection 1 and pain 1). Kaplan-meier survival analysis revealed 100% survival for aseptic loosening, 96.8% survival for stem failure and 88.9% survival for all causes.
This is the largest series with the longest follow up of the Exeter 44/00 short revision stem. The stem performs equally well as standard Exeter stems with regards to aseptic loosening. The single stem fracture occurred secondary to bone loss in chronic infection, highlighting the importance of providing adequate proximal support for the stem. Periprosthetic fracture occurred in 2.4% of this series of revision cases.
Larger registry-based studies may provide additional information on the performance of this stem.
Introduction
Operating theatre airflow can be measured using pulsed lasers (particle image velocimetry) but the process is difficult to do in 3D. Cup, vane or hot wire anemometers provide only 2D information. 3D measurements enable better understanding of airflow.
Patients/Materials & Methods
We used a Windmaster ultrasound 3D anemometer (Skyview systems), which uses three ultrasound transmitters to measure velocity in XYZ planes, with a sampling rate of 32 Hz. Post processing was done using MATLAB.
An operating theatre with an Howorth Exflow canopy was studied. Equipment, including lights, was moved. A 50 cm grid was marked, and measurements were made at intervals up to the ceiling.
Door opening was observed within the clean zone and the peripheral zone, next to the door and on the opposite side of the room.
Anaesthetic screens were studied during operating. Airflow was visualised initially using video of smoke puffs and subsequently measured using the aeronometer.
Introduction
Reverse hybrid total hip replacement (THR) offers significant theoretical benefits but is uncommonly used. Our primary objective was to evaluate implant survival with all cause revision and revision for aseptic loosening of either component as endpoints.
Patients/Materials & Methods
Data was collected prospectively on 1, 088 (988 patients) consecutive reverse hybrid THRs. Mean patient age was 69.3 years (range, 21–94) and mean follow-up was 8.2 years (range, 5–11.3). No patients were lost to follow-up. Overall, 194 (17.8%) procedures were performed in patients under 60 years, 666 (61.1%) were performed in female patients and 349 (32.1%) were performed by a trainee. Acetabular components were ultra-high molecular weight polyethylene in 415 (38.1%) hips, highly cross-linked polyethylene in 669 (61.5%) hips and vitamin E stabilised polyethylene in 4 (0.4%) hips. Femoral stems were collared in 757 (69.7%) hips and collarless in 331 (30.3%) hips. Femoral head sizes were 28 mm in 957 (87.9%) hips and 32 mm in 131 (12.1%) hips. Survival analysis was performed using Kaplan Meier methodology. Log rank tests were used to asses differences in survival by age, gender, head size and surgeon grade.
Background
Short bone-conserving femoral stem implants were developed to achieve more physiological, proximal bone loading than conventional femoral stems. Concerns have arisen, however, that improved loading may be offset by lower primary stability because of the reduced potential area for bony contact.
Aims
The aim of this study was to determine the primary stability of a novel short femoral stem compared with a conventional femoral stem following cementless total hip arthroplasty (THA), in a prospective, blinded, randomised, controlled trial using radiostereometric analysis.
Introduction
Undersizing of an uncemented femoral stem is a post-operative description of a radiograph with unclear clinical importance. It may not always translate into a suboptimal clinical outcome.
Aim
To describe a novel classification system of undersizing in a fully hydroxyapatite coated femoral implant, assess if it could be reliably reported between observers, and describe a simple way to assess the degree of undersizing on an AP radiograph.
Introduction
Modular-neck hips have twice the rate of revision compared to fixed stems. Metal related pathology is the second most common reason for revision of implants featuring titanium stems with cobalt chrome necks. We aimed to understand the in-vivo performance of current designs and explore the rationale for their continued use.
Methods
This study involved the examination of 200 retrieved modular-neck hips grouped according to the material used for their neck and stem. Groups A, B and C had neck/stems featuring CoCr/beta Ti-alloy (TMZF), CoCr/Ti6Al4V-alloy, and Ti6Al4V/Ti6Al4V respectively. Reasons for revision included pain, elevated metal ion levels and fluid collection. The stem-neck interface was assessed for severity of fretting/corrosion using metrology methods to compute linear wear penetration rate.
Introduction
The use of larger femoral heads in Total Hip Arthroplasty has increased in order to reduce the risk of dislocation and to improve the range of motion of the joint. In 2003, within the UK, the “standard” head size of 28mm was used in 73% of all hip procedures, whereas by 2012, this figure dropped to 36%. Concerns regarding the impact of this increment in head size on the cement and bone stresses have arisen; however, this has yet to be clearly determined.
Methods
To understand the relationship between femoral head size and cement mantle and bone stress in cemented hip arthroplasty, 3D-Finite-Element models of a hemipelvis with cemented cup[tb6] (50mm outer-diameter) were developed. Loading conditions of single-leg-stance (average and overweight) were simulated for three head sizes (28, 32 and 36mm). The models were validated with an in-vitro experiment using the average loading condition.
Osteoarthritis of the hip is common and the mainstay of surgical treatment for end-stage disease is total hip replacement. There are few RCTs comparing long-term outcomes between prostheses; therefore, surgeons and patients are reliant on single-centre case-series and recently, analysis of joint registries, when making evidence-based implant choices.
We conducted a systematic review, conforming to PRISMA, of Medline and Embase in September 2017. Single-centre case-series and papers analysing registries were included. Series looking at disease-specific cohorts (other than OA), under 15 years follow-up or lacking survival analyses were excluded. Resurfacings, revisions and complex-primaries were also excluded. 2750 abstracts were screened, resulting in 299 full-text articles. Following full review 124 articles were excluded and 21 series added from references, resulting in 150 analyses of individual prostheses/constructs and 12 papers from registries. We also analysed annual reports of registries.
Registry data indicated cemented prostheses tended to better outcomes at late follow-ups, whereas case-series showed cementless prostheses tended to have better survival past 15 years with revision for any reason (of stem, cup or either component) as the end-point.
The discrepancy between results from registry data and single-centre case series is stark, and whilst the reasons for these differences may be multifactorial, single-centre case-series included in this review often lacked sufficient power to provide precise estimates of survival. This is contrasted to data from registries, which tended to have far greater numbers from multiple centres, allowing results to be generalised to the population.
The difference between these two modes of analysis suggests bias exists in selection and outcomes from single-centre series. The varied quality of reporting in case-series make it difficult for a reader to adequately assess bias, and accurately inform contemporary decision making.
Surgeons and patients should be cautious when interpreting single-centre case series and systems relying on data generated from them.
Introduction
Severely comminuted, displaced acetabular fractures with articular impaction in the elderly population present significant treatment challenges. To allow early post-operative rehabilitation and limit the sequelae of immobility, treatment with acute total hip replacement (THA) has been advocated in selected patients. Achieving primary stability of the acetabular cup without early migration is challenging and there is no current consensus on the optimum method of acetabular reconstruction. We present clinical results and radiostereometric analysis of trabecular metal (TM) cup cage construct reconstruction in immediate THA without acetabular fracture fixation.
Methods
Between 2011 and 2016, twenty-one acetabular fractures underwent acute THA with a TM cup cage construct. Patient, fracture and surgical demographics were collected. They were followed up for a mean of 24months (range 12–42months). Clinical and patient reported outcome measures were collected at regular post-operative intervals. Radiosterometric analysis (RSA) was used to measure superior migration and sagittal rotation of the acetabular component.
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.
