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Objective
The objective of this study was to assess the biomechanical stability of three types of chondral flap repair and a hydrogel scaffold implantation on the acetabular articular surface using a physiological human cadaveric model.
Methods
Chondral flaps were created in the antero-superior zone of the acetabulum in a series of human cadaveric hip joints. The chondral flap was repaired by fibrin glue, cyanoacrylate, suture technique and an agarose hydrogel scaffold sealed with fibrin glue using 6 hips in each case. After each repair, the specimens were mounted in a validated jig and tested for 1500 gait cycles. In order to determine the stability of the repair, specimens were evaluated arthroscopically at specific intervals.
Introduction
Retrieved metal-on-metal acetabular components are invaluable resources from which to investigate the wear behaviour of failed hip implants. New forensic and investigative techniques continue to be developed to help the surgeon further understand factors which contribute to early failure. We have developed a novel technique to locate the in vivo location of the primary wear scar of an explanted cup.
Patients/Materials & Methods
Thirteen (13) patients with failed metal hip resurfacings were recruited and their acetabular components retrieved. A 3D wear map was generated and the precise location of the primary wear scar in each cup was identified using a coordinate measuring machine (CMM). This wear scar position and location was noted in relation to standard landmarks on the acetabular cup. All patients underwent a computerised tomography (CT) scan prior to revision surgery. The 3D positional map from the CMM was then co-registered with the implant on the patient's pelvic 3D CT scan.
Introduction
One unpredictable clinical risk with THA may be impingement of a metal cup rim against a metal femoral-neck, with concomitant release of metal particles. Our objective was to determine if metal debris could be one trigger for catastrophic MOM wear.
Patients/Materials & Methods
To simulate release of metal debris, we added metal particles (CoCr #230, Ti6Al4V #340) to six 38mm MOM bearings at beginning of each simulator test interval. The weekly 500,000 cycle intervals were replicated 10 times to acquire 5-million duty cycles. Flakes of polymerized bone cement (PMMA) were scraped from a retrieved TKR and used as control debris (N = 1,300 particles; 3 MOM).
Introduction
Recent studies on large diameter femoral head hip replacements have implicated the modular taper junction as one of the significant sources of wear and corrosion products and this has been attributed to increased torque and bending on the taper interface. The aim of this study was to assess the effect of frictional torque and bending moment on fretting corrosion at the taper junction and to investigate whether different material combinations also had an effect.
Patients/Materials & Methods
We examined 1) Cobalt Chromium (CoCr) heads on CoCr stems 2) CoCr heads on Titanium alloy (Ti) stems and 3) Ceramic heads on CoCr stems. In test 1 increasing torque was imposed by offsetting the femoral stem in the anterior posterior plane in increments of 0 mm, 4 mm, 6 mm and 8 mm where the force generated was equivalent to 0Nm, 9Nm, 14Nm and 18Nm. In Test 2 we investigated the effect of increasing bending moment by offsetting the application of axial load from the midline in the medial-lateral (ML). Offset increments equivalent to +0, +7 and +14 heads were used. For each test we used n=3 for each different material combination.
Introduction
In this study, we aimed to investigate the effect of the topography of the female taper surface on taper wear.
Patients/Materials & Methods
We measured volumetric material loss at the female taper surface of the first consecutive 36mm MoM hips received at our centre. The MoM hips were from a single manufacturer and possessed matching: head size (36mm); taper geometry (5.65 degree 12 14 tapers); and metallurgy (cobalt chrome female taper mated with a titanium stem). Volume loss was measured with a coordinate measuring machine using validated methods. Surface roughness was measured using a Surftest SJ400. There were 111 head tapers available for analysis. The majority had been revised secondary to ARMD, and a minority for loosening. The mean duration of implantation was 56 months. Volumetric wear values were log normalised in order to construct a multiple regression model to investigate the interaction of head offset, the head taper angle and the Rp value of the female taper surface. Rp is a roughness parameter, which is a measure of the peaks above the plateau of a surface.
Periprosthetic femoral fractures are a challenging problem to manage. In the literature various constructs have been designed and tested, most requiring cables for proximal fixation. The Synthes Locking Attachment Plate (LAP) has been designed to achieve proximal fixation without the use of cables.
The aim of this study was to biomechanically evaluate the LAP construct in comparison to a Cable plate construct, for the fixation of periprosthetic femoral fractures after cemented total hip arthroplasty (THA).
Twelve synthetic femora were tested in axial compression, lateral bending and torsion to determine initial stiffness, and stiffness following fixation of a simulated midshaft fracture with and without a bone gap. Two different fracture fixation constructs (six per group) were assessed. Each construct incorporated a broad curved LCP with bi-cortical locking screws for distal fixation. In the Cable construct, 2 cables and 2 uni-cortical locking screws were used for proximal fixation. In the LAP construct, the cables were replaced by a LAP with 4 bicortical locking screws. Axial, lateral bending and torsional stiffness were assessed using intact specimen values as a baseline. Axial load to failure was also measured. The LAP construct was significantly stiffer than the cable construct under axial load with a bone gap (simulating a comminuted fracture) (p=0.01). There were no significant differences between the two constructs in any of the other modalities tested. Loading to failure resulted in no significant differences between constructs, in either initial stiffness or peak load.
In conclusion the LAP construct enables bi-cortical screw fixation around a prosthesis. Compared to cables, this was stiffer when there was a bone gap and thus should offer improved proximal fixation of Vancouver B1 proximal femoral fractures in cemented THA.
Introduction
Alpha angles have been used to identify the precise area on the femoral head/neck junction that causes cam-type FAI. Now, computer programs are available to calculate the precise motion pattern of a hip joint and identify areas of FAI, dysplasia and other morphological abnormalities. We hypothesise that one cannot rely on the alpha angle alone to predict the precise area of resection required to remove cam impingement.
Methods
We used Clinical Graphics software to analyse a cohort of 142 hips. We recorded the alpha angle at 12, 1, 2 and 3 o'clock and whether resection was recommended by the software at these points. We then removed the patients with acetabular influences on potential FAI (pure cam group).
Introduction
Successful joint preservation surgery requires the ability to accurately assess the health of the articular cartilage pre-operatively. Traditional radiological methods allow morphological assessment of the cartilage and therefore only identify those with established degeneration. Biophysical properties of cartilage are now being used to identify these changes occurring earlier in the disease processes. Prior literature states that healthy cartilage has a transverse relaxation time of between 15–60 ms (16). Our study aims to establish the correlation and accuracy of MRI with T2 cartilage mapping with observed intra-operative chondral defects.
Methods
We routinely request MRI with T2 mapping on all patients with suspected or confirmed femoroacetabular impingement (FAI). A review was performed on all patients who underwent both pre-operative imaging and subsequent hip arthroscopy for FAI over a 24-month period. Using linear regression we correlated intra-operatively observed chondral defects of the femoral head and acetabulum (Outerbridge classification scores) with the pre-operative transverse relaxation times. Statistical analysis of 66 chondral points was undertaken.
Introduction
Femoroacetabular impingement (FAI) is a common cause of hip symptoms in younger patients. Failure to completely address the deformity yields a poor surgical result. Therefore accurate assessment is imperative to good outcome.
Dynamic motion analysis offers improved assessment of the morphological pathology causing FAI. This study aims to compare the differences in measurement reports produced by 3-Dimensional analysis of CT scans for FAI between two systems, Clinical Graphics (Delft, Holland) and Dyonics Hip Plan by Smith & Nephew (London, UK).
Patients/Materials & Methods
The senior author uses computerized tomography (CT) with three-dimensional reconstructions and dynamic motion analysis. A series of scans were analysed with both systems, and equivalent data was recorded from each.
This included femoral neck version, femoral neck inclination, acetabular anterior coverage (%), acetabular posterior coverage (%), alpha angle at 9, 10, 11, 12, 1, 2 and 3 o'clock positions, centre-edge angle at 12 o'clock, acetabular version and suggested resection.
Introduction
Hip Osteoarthritis (HOA) is a highly heterogeneous disease with potentially different genetic aetiologies. Thus far, few genetic variants have been robustly associated with broad definitions of HOA. We aimed to identify novel HOA susceptibility variants by examining a set of more homogeneous, radiographically-derived endophenotypes relating to anatomic pattern of joint involvement and bone remodelling response in HOA.
Materials, Methods and Results
Individuals with HOA and AP-hip radiographs (n=2,109) were selected from the arcOGEN study, genotyped on 2 platforms. The most arthritic hip per patient was categorised using Bombelli's classification (atrophic/normotrophic/hypertrophic), and for pattern of joint space narrowing (superior/medial-axial/concentric). Following 1000-Genomes-Project-based imputation and stringent quality control over 7 million variants were tested for association with each phenotype under the additive model. Fixed-effects meta-analysis was used to combine the results from the two GWA studies.
In the discovery GWAS of atrophic HOA vs cases with non-atrophic HOA a strong signal (rs16869403, OR[95% CI]=2.47[1.81–3.38], p=1.53×10−8) was detected in the G protein-coupled receptor,
Introduction
Aseptic loosening, the clinical endpoint of osteolysis, remains the leading cause of total hip arthroplasty (THA) failure, and is caused by a host response to wear debris that varies between individuals. Although several candidate gene studies have identified loci associated with osteolysis susceptibility, there have been no systematic studies at genome-wide level. We aimed to identify risk loci associated with osteolysis by conducting a genome-wide association study.
Methods
3,706 Caucasian European patients following THA were studied. The discovery cohort comprising 894 patients (317 with osteolysis) were genotyped using the Illumina-610 beadchip followed by 1000 Genome-based imputation covering 10 million single nucleotide polymorphisms (SNPs). Phenotypes were transformed to normality where required, regressed on important covariates and z-standardised. Following quality control, osteolysis case-control analysis and a quantitative trait association analysis for time to prosthesis failure were undertaken. Index SNPs p<9×10−4 were taken forward for replication in a second cohort comprising 2,812 subjects (834 osteolysis cases) recruited from the Norwegian arthroplasty registry. Genotyping was undertaken using Sequenom MassARRAY iPLEX Gold assay and association analyses undertaken using logistic and linear regression. Summary statistics were combined in a fixed-effects meta-analysis framework.
Introduction
In rheumatoid (RA) patients undergoing total joint arthroplasty, evidence suggests methotrexate should be continued without increase in post-operative infection. Prednisolone increases post-operative infection risk, but cannot be stopped without risk of Addisonian events. Insufficient evidence exists to clarify perioperative biologic agent management. We currently stop biologics 2 weeks prior to operation and reintroduced following wound healing.
Patients/Materials & Methods
This service evaluation reviewed infection rates and length of stay in RA patients following lower-limb arthroplasty, on various anti-rheumatoid therapies across a 28-month period.
Introduction
The National Institute for Health and Care Excellence (NICE) currently recommends the use of total hip replacement (THR) for displaced intracapsular hip fractures in cognitively competent patients and who were independently mobile with the maximum use of one stick prior to the injury.
Method
We conducted a prospective cross sectional study of the management of hip fractures within a defined geographic region in the North East of England to assess current practice and variation in provision of THR for displaced intracapsular hip fracture.
Introduction
In recent years the relationship between hyponatraemia and bone metabolism, falls and fractures has become more established. In this study hyponatraemia was an independent risk factor for increased post-operative mortality on multivariate analysis.
Patients/Materials & Methods
This study retrospectively evaluates the prevalence of hyponatraemia (plasma sodium <135 mmol/l) in 3897 patients undergoing operative treatment for hip fracture and the relationship between hyponatraemia and mortality in these patients.
Introduction
A fractured hip is the commonest cause of injury related death in the UK. Prompt surgery has been found to improve pain scores and reduce the length of hospital stay, risk of decubitus ulcer formation and mortality rates. The hip fracture Best Practice Tariff (BPT) aims to improve these outcomes by financially compensating services, which deliver hip fracture surgery within 36 hours of admission. Ensuring that delays are reserved for patients with conditions which compromise survival, but are responsive to medical optimisation, would facilitate enhanced outcomes and help to achieve the 36-hour target.
We aimed to identify medical conditions associated with patients failing to achieve the 36-hour cut off, and evaluated whether these were justified by calculating their associated mortality risk.
Methods
Prospectively collected data from the National Hip Fracture Database (NHFD) and inpatient hospital records and blood results from a single major trauma centre were obtained. Complete data sets from 1361 patients were available for analysis. Medical conditions contributing to surgical delay beyond the BPPT (Best Practice Tariff Target) 36-hour cut off, were identified and analysed using univariate and multivariate regression analyses, whilst adjusting for covariates. The mortality risk associated with each factor contributing to surgical delay was then calculated using univariate and hierarchical regression techniques.
Introduction
Occult hip fractures occur in 3% of cases. Delay in treatment results in significantly increased morbidity and mortality. NICE guidelines recommend cross-sectional imaging within 24 hours and surgery on the day of, or day after, admission. MRI was the standard imaging modality for suspected occult hip fractures in our institution, but since January 2013, we have switched to multi-detector CT (MDCT) scan.
Our aims were to investigate whether MDCT has improved the times to diagnosis and surgery; and whether it resulted in missed hip fractures.
Patients/Materials & Methods
Retrospective review of a consecutive series of patients between 01/01/2013 and 31/08/2014 who had MDCT scan for suspected occult hip fracture. Missed fracture was defined as a patient re-presenting with hip fracture within six weeks of a negative scan. A comparative group of consecutive MRI scans from 01/01/2011 to 31/12/2012 was used.
Introduction
Magnetic resonance arthrogram (MRA) is the investigation of choice in young adults with symptoms of femero acetabular impingement. The aim of the study is to assess the accuracy of MRA when correlated with surgical findings on hip arthroscopy.
Materials and Method
Between June 2007 and January 2014, 136 patients had MRA followed by subsequent arthroscopy at our institution. The radiology information system was used to gather MRA data. All scans were reported by a consultant radiologist with a specialist interest in musculoskeletal radiology. Patient records were reviewed to gather surgical data. Assessment was made of labral injury, Camshaft (CAM) or Pincer lesion and degeneration of the cartilage.
Introduction
Periacetabular osteotomy has been described as an effective way of treating symptomatic hip dysplasia. We describe a new minimally invasive technique using a modification of the Smith Peterson approach.
Patients/Materials & Methods
189 consecutive patients operated on between March 2010 and March 2013 were included in the study. Patients who had undergone previous pelvic surgery for DDH were excluded. There were 174 females and 15 males. The mean age was 31 years (15–56) and the mean duration of follow-up was 29 months (14 – 53 months). 90% of cases were Tonnis grade 0 or 1. Twenty-three patients were operated on for primary acetabular retroversion. Functional outcomes were assessed using the NAHS, UCLA and Tegner activity scores.
The surgical procedure is performed through an 8–10 cm skin crease incision; a soft tissue sleeve is elevated from the anterior superior iliac spine. The interval medial to the rectus femoris is developed. The hip joint is not opened and fixation of the osteotomy was with three 4.5mm cortical screws. A cell saver was routinely used.
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. We aim to assess survivorship and functional outcome at ten years, in patients who have undergone open hip debridement.
Patients/Materials & Methods
All patients who had undergone open debridement surgery were identified on our database. The electronic, radiographic and paper records were reviewed. Demographic data, radiological and operative findings were recorded. All patients underwent ten year review with a standardised AP hips radiograph, questionnaire, non-arthritic hip score (NAHS), oxford hip score (OHS) and SF12 score.
Introduction
Hip and groin injuries are common in athletes participating in high level sports. Adductor muscle tendon injuries represent a small but important number of these injuries. Avulsion injuries involving tendons attaching to the symphysis pubis have previously been described and can be managed both operatively and non-operatively.
The aim is to describe a rare variant of this injury; complete avulsion of the adductor sleeve complex including adductor longus, pectineus and rectus abdominus. A surgical technique is then outlined which promotes a full return to pre-injury level of sporting activity.
Patients/Materials & Methods
Fifteen high level athletes with an MRI confirmed acute adductor complex avulsion injury (6–34 days) were identified from the institution's sports injury database over a 10 year period. All underwent surgical repair. The operative procedure comprised anatomical attachment of the avulsed tissues in all cases (plus mesh reinforcement of the inguinal wall in 7 patients). All underwent a standard format of rehabilitation which was then individualised to be sport specific.
Introduction
The prevalence of adverse reactions to metal debris (ARMD) associated with metal on metal (MoM) hip arthroplasty has been reported to be as high as 69%. Such findings promoted the development of metal-artefact reducing sequence (MARS)-magnetic resonance imaging (MRI) classifications, with the aim of stratifying soft lesions by severity of disease. The Modified Oxford Classification is a straightforward system that has been shown to correlate with disease progression.
Methods
The aim of this study was to test the reliability of this classification between observers. Seven observers were recruited, all with a musculoskeletal background. Using the PACS image analysis system, 20 MARS-MRI scans were provided for interpretation. Observers reviewed these scans in random order at two separate intervals over the course of five weeks. They classified them according to the Modified Oxford Classification as: ‘normal’, ‘trochanteric fluid, ‘effusion’, ‘ARMD type 1’, ‘ARMD type 2’ and ‘ARMD type 3’.
Introduction
The prevalence of adverse reactions to metal debris around metal-on-metal (MOM) hip replacements has been reported to range from 7 to 69%. Little has been published on MRI scans with conventional total hip bearing surfaces. This study aimed to establish the prevalence of soft tissue lesions associated with metal-on-polyethylene (MOP) and ceramic-on-ceramic (COC) bearings, compared to MOM prostheses.
Patients/Materials & Methods
All Metal Artefact Reduction Sequence (MARS) MRI scans for MOM THRs performed at our unit from January 2009 to present were reviewed, identifying those with contralateral primary MOP or COC THRs included on the scan. These were compared to a previously analysed cohort of 281 MOM THRs. Scans were classified using the Modified Oxford Classification as ‘Normal’, ‘Trochanteric Fluid’, ‘Effusions’ or Adverse Reactions to Debris.
Introduction
Incidence of adverse soft tissue reaction following metal on metal hip has a reported incidence of up to 48%. The current imaging modality of choice is metal artefact reduction sequence (MARS) MRI. Consensus is that large, symptomatic pseudotumours should be treated surgically, changing the bearing surfaces to other materials. There is debate as to how asymptomatic pseudotumours should be monitored and managed.
Patients/Materials & Methods
From our unit's database, 22 patients (7 female, 15 male) were identified with metal on metal hip replacements that had a ‘pseudotumour’ detected on MARS MRI but remained assymptomatic (mean 68 months post op). All underwent serial imaging and clinical follow up (mean interval 14.5 months).
Introduction
This study aimed to: (1) compare published follow-up guidelines for metal-on-metal (MoM) hip patients and analyse protocols in relation to current evidence, and (2) assess the financial implications of these guidelines.
Methods
Follow-up guidance for MoM hips from five national authorities (MHRA in the UK; EFORT; United States FDA; Therapeutic Goods Administration of Australia; Health Canada) were contrasted and critically appraised. Using National Joint Registry (NJR) data (67,363 MoM hips implanted) the cost of annual surveillance for all MoM hips recorded in the NJR was calculated for each protocol.
Introduction
Little is known about variations in blood metal ions following bearing exchange for poorly functioning metal-on-metal hip replacements (MoMHRs). This study aimed to determine the changes that occur in blood and urine metal ion concentrations following MoMHR revision.
Methods
Between 2005–2012, a single-centre prospective cohort study was undertaken of patients with large-diameter MoMHRs and high blood metal ions requiring revision. Whole blood and urine were collected both pre-revision and post-revision for metal ion analysis.
Introduction
The National Joint Registry (NJR) for England, Wales and Northern Ireland contributes important information on the performance of implants and surgeons. However, the quality of this data is not known. This study aimed to perform an independent validation of primary metal-on-metal hip procedures recorded on the NJR through linkage to the London Implant Retrieval Centre (LIRC).
Patients/Materials & Methods
Primary, metal-on-metal hip arthroplasties performed between 1st April 2003 and 5th November 2013 were recruited from the NJR (n=67045). Retrieved, metal-on-metal components were recruited from the LIRC (n=782). Data linkage and validation checks were performed.
Introduction
Uncertainties in the management of patients with MOM hip implants continue to be a problem for all surgeons. Guidelines vary and do not fully define or quantify thresholds. We aimed to assess the differences in decision-making amongst an international community of six specialist orthopaedic institutions.
Methods
Five international tertiary referral orthopaedic units (one UK, two USA, and two European) were invited to participate. Each unit organised an MDT panel consisting of 2 or more hip surgeons and a musculoskeletal radiologist. All units discussed the same 10 patients. A full clinical dataset was provided including blood test and all imaging. Differences in the interpretation of findings, management decision and rationale for decisions were compared between institutions.
Introduction
Slipped upper femoral epiphysis (SUFE) predominantly affects males in early adolescence. Severe slips occur with an estimated incidence of 1 per 100,000 children. Controversy exists over optimal treatment of severe slips with debate between in-situ fixation versus corrective surgery. We report on our management of a large series of such patients using a sub-capital cuneiform osteotomy.
Patients/Methods
Between 2001–2011, 57 patients (35M: 22F) with an average age of 13.1 years were referred to our tertiary referral institution with a severe slip. This was defined as an epiphyseal-metaphyseal displacement greater than half the width of the femoral neck on a Billing lateral radiograph. The affected limb was rested in slings and springs prior to corrective surgery which was performed via an anterior Smith-Petersen approach. More recently our series has included pre-operative MRI to look for avascular necrosis of the epiphysis. Data was analysed to compare complication rate with time to surgery and surgeon's experience.
Introduction
Joint preserving procedures have gained popularity in an attempt to delay arthroplasty in young, dysplastic hips. Excellent results can be achieved with peri-acetabular osteotomy (PAO) in congruent non-arthritic hips. The role of salvage procedures such as the Shelf acetabuloplasty remains undefined. This study aims to determine the long-term survival and functional outcome following Shelf acetabuloplasty and to identify factors that influence outcome.
Patients/Materials & Methods
This is a retrospective, consecutive, multi-surgeon, case series from a UK referral centre. 125 Shelf procedures were performed between 1987–2013 on 117 patients for symptomatic hip dysplasia. Mean age was 33 years (15–53). Mean follow-up was 10 years (1–27). Radiographic parameters measured included pre-operative arthritis, acetabular-index, centre-edge-angle, joint congruency, subluxation and femoral sphericity. Oxford Hip and UCLA scores were collected at follow-up. Failure was defined as conversion to arthroplasty or OHS<20.
Introduction
Total Hip Replacement (THR) is an effective treatment for end stage degenerative disease of the hip and offers patients the prospect of long term pain relief, improved joint function and quality of life. Enhanced Recovery Programmes (ERP) aim to standardise routine perioperative care, reduce hospital length of stay (LOS) and promote rapid recovery after elective surgery. The aim of this study was to determine whether the implementation of an ERP could successfully reduce the length of hospital stay associated with primary THR and whether this could be achieved without compromising the expected functional outcome or risking an increased dislocation rate.
Patients/Materials & Methods
Prospectively collected data on 1161 patients (611 managed with traditional rehabilitation and 550 with ERP) undergoing primary unilateral THR between 2005 and 2013 was retrospectively reviewed. Univariable statistical analysis was undertaken to identify factors that appeared to predict length of stay and a multiple linear regression model was then constructed to determine the significance and strength of effect of the individual predictors.
Introduction
The Direct Anterior Approach (DAA) offers potential advantages of quicker rehabilitation compared to posterior approach THR. The aim of this study was to compare hospital based and early clinical outcomes between these two groups with utilisation of Enhanced Recovery After Surgery (ERAS) protocol.
Patients/Materials & Methods
Prospectively collected data for both cohorts were matched for age, gender, ASA grade, BMI, operation side, Pre-operative Oxford Hip score (OHS) and attendance at multi-disciplinary joint school. The pain scores at 0,1,2,3 post-op days, the day of mobilization, inpatient duration, complications, 28 days readmission rates and OHS at 6 and 24 months were compared.
Introduction
Operative inclination (OI) is defined as the angle between the acetabular axis and the sagittal plane. With the patient in the true lateral decubitus position, this corresponds to the angle formed between the handle of the acetabular component inserter and the theatre floor intra-operatively.
Patients/Materials & Methods
The primary study aim was to determine which method of acetabular component insertion most accurately allows the surgeon to obtain a target OI of 35o.
270 consecutive patients undergoing cementless THA were randomised to one of three possible methods for acetabular component implantation:
1. Freehand,
2. 35o mechanical alignment guide (MAG), or
3. Digital inclinometer assisted
Two surgeons participated. Target OI was 35o in all cases. OI was measured using a digital inclinometer. For the freehand and MAG cases, the surgeon was blinded to inclinometer readings intra-operatively.
Introduction
A high inclination angle has been linked to an increased dislocation rate, liner fracture, and increased wear. The aim of this study was to compare the operative (OI) with the radiological inclination (RI) angle and determine the influence of patient morphology on pelvic tilt and cup inclination angle.
Methods
In the first cohort of 100 patients undergoing uncemented primary total hip arthroplasty, the cup was inserted freehand. In the second cohort of 100 patients, the OI was measured with the aid of a digital inclinometer. RI and pelvic tilt in lateral decubitus were measured.
Introduction
Obesity is known to influence surgical risk in total hip replacement (THR), with increased Body Mass Index (BMI) leading to elevated risk of complications and poorer outcome scores. Using a multinational trial data of a single implant, we assess the impact of BMI and regional variations on Harris Hip scores (HHS).
Method
We assessed BMI in 11 regional centres and associations with HHS at one year. Data were collected from 744 patients prospectively from 11 centres in the UK, Germany, Switzerland, Austria, New Zealand and Netherlands as part of a multicentre outcome trial. All Arthroplasties used RM Pressfit vitamys components (Mathys, Switzerland). Demographic, operative data and HHS were analysed with General Linear Model Anova, Minitab 16 (Minitab Inc, Pennsylvania).
Introduction
Functional scores are used to clinically assess total hip arthroplasty (THA) and for comparative purposes in the orthopaedic literature. Previous research has highlighted patient age, gender and underlying diagnosis as potential sources of bias but comorbidity has not been considered. The Functional Comorbidity Index (FCI) is a published epidemiological tool which correlates disease with associated physical function deficit. It scores 18 conditions: one point for each, total score 0–18.
Method & Results
We analysed 41 fully cemented primary THAs in patients ≤55 years at time of surgery with a minimum 10 years follow up. Past medical history was collected via thorough case note review. Patients were assessed using the SF-12 questionnaire, Harris Hip and WOMAC indexes.
The study population consisted of 29 patients: 12 women, 17 men. Mean age: 45 years (range 22–53). All patients received cemented polished Corin TaperFit stem with polyethylene Ogee cup. Mean follow up 13.4 years (range 10.2–17.7).
FCI scores ranged 0–3 (12 hips=0; 19 hips=1, 5 hips=2, 5 hips=4). A Pearson's product-moment correlation coefficient was calculated to assess the relationship between co-morbidity and hip function score using all three indexes.
Mean by FCI subgroup: 0=91, 1=96, 2=76.8, 3=68.6 (r=−0.407)
Mean by FCI subgroup: 0=94.7; 1=88.2, 2=63.5, 3=54.6 (r= −0.813)
Mean by FCI subgroup: 0=94.4, 1=91.72, 2=48.8, 3=37.4 (r=−0.812)
Introduction
There is a paucity of research investigating the effect of the experience of the operating surgeon on the long term function and survivorship of total hip replacements (THR). With the advent of individualised surgeon data being available to patients via the National Joint Registry, the desire to avoid complications and poor performance grows. This potentially reduces the availability of operative opportunities for trainees as consultants seek to ensure good results.
Method & Results
A multicentre retrospective study of 879 THR was undertaken to investigate any differences in outcome between trainee surgeons and consultants. The effect of trainee supervision on the surgical outcome was also assessed. The primary outcome measures were survivorship and the Harris Hip Score (HHS). Rates of deep infection and dislocation were also recorded. Patients were evaluated pre-operatively and at 1, 3, 5, 7 and 10 years post-operatively. Surgical outcome was compared between junior trainees, senior trainees and consultants. The effect of supervision on final outcome was determined by comparing supervised and unsupervised trainees.
66.4% of patients were operated by consultants, 15.7% by junior trainees (ST3–5 equivalent) and 16.8% by senior trainees (ST6–8 equivalent). 10 year implant survival rates were; consultants 96.4 %, senior trainees 98.0 % and junior trainees 97.1%. There was no significant difference in post-operative HHS among consultants, senior and junior trainees at 1 year (p=0.122), 3 year (p=0.282), 5 year (p=0.063), 7 year (p=0.875), or at 10 years (p=0.924). There was no significant difference in HHS between supervised and unsupervised trainees at 1 year (p=0.220), 3 year (p=0.0.542), 5 year (p=0.880), 7 year (p=0.953) and 10-years (p=0.787). Comparison of surgical outcome between the supervised and unsupervised trainees also shows no significant difference in implant survival years (p=0.257).
Introduction
Cemented stems have given good results with no difference in outcome when comparing taper slip and composite beam designs in short-term randomised trials. We aimed to ascertain differences in outcome between the different cemented design philosophies using a large-scale registry analysis.
Materials and Methods
A retrospective cohort study of National Joint Registry of England and Wales (NJREW) was conducted. The study population included all primary total hip operations performed in the UK from 1 April 2003 to 31 September 2012. All cemented stems were identified and categorised as taper slip (polished) or composite beam (non-polished).
Introduction
Despite an ageing population and a rise in the number of joint replacements being performed, the mean age of patients undergoing surgery remains static. One explanation for this is continued concern over the risks of performing surgery on the very elderly. The Elective Orthopaedic Centre, Epsom has an established patient reported outcome measures (PROMs) programme into which all patients are routinely enrolled. Post-operative complications, Oxford scores and Euro-Quol (EQ5-D) are collected to the second post-operative year.
Methods and Results
We retrospectively reviewed our data set for a cohort of nonagenarians undergoing primary total hip replacement (THR) between April 2008 and October 2011. Post-operative complications, mortality rates and functional outcomes were compared to those of a time matched 70–79 year old cohort. Only patients with a primary diagnosis of osteoarthritis were included whereas an exclusion criterion consisted of patients undergoing revision surgery, simultaneous bilateral replacements or conversion from a dynamic hip screw.
We identified 38 nonagenarian patients (12 men and 26 women), with a mean age of 92.18 (90–99) and the control group consisted of 55 patients (21 men and 34 women), with a mean age of 74.69 (70–79).
We found that nonagenarians requiring a THR presented with lower pre-operative Oxford Hip Score (OHS) (p=0.02) but made a greater improvement in the first post-operative year than the younger cohort (p=0.040). The nonagenarians had a greater risk of requiring a blood transfusion following THR (p= 0.0265; CI 1.11 to 5.75), and also required a longer stay than their younger counterparts (p=0.001). Mortality rates were higher in the nonagenarian cohort, but these were in keeping with the life expectancy projections identified by the Office for National Statistics (ONS).
Introduction
The longevity of total hip replacements in young active patients is a cause for concern as increased cyclical loading can result in early loosening of implants resulting in multiple revisions during the patient's lifetime. The study presented demonstrates excellent survival of the HAC-coated femoral stems in young active individuals.
Patients/Materials & Methods
33 Patients under 50 years of age underwent 38 total hip arthroplasties using the JRI Furlong HAC-coated femoral stem. The retrospective evaluation of the prospectively collected data of the cohort at 17 to 25 years is presented.
Introduction
There is sparse evidence regarding the survivorship beyond 20 years of both uncemented and cemented hip replacements in patients 50 years and under. We report a unique series reviewing 20–26 year follow-up of patients ≤50 years with cemented Exeter THR.
Materials and Methods
We reviewed the survivorship with clinical and radiological outcomes of 138 consecutive cemented THR's in 113 patients ≤50 years. The pre-op diagnoses included Osteoarthritis (30%), DDH (25%), RA (9%) and Post traumatic OA (5%), and 31% of patients had previous surgery to the hip. All patients were followed up at 5 year intervals and there was no patient lost to follow up.
Introduction
Gaucher Disease (GD) is the commonest of the lysosomal storage disorders. Orthopaedic manifestations occur in 90% and include osteonecrosis of the femoral head, often producing severe disability at a young age. Historically, arthroplasty has been avoided in GD due to high reported rates of haemorrhage and decreased implant survival. The advent of enzyme replacement therapy (ERT) has revolutionised GD treatment with correction of haematological parameters within five months. However there is little data regarding the effect of ERT on the outcomes of hip arthroplasty.
Materials and Method
All patients on the Cambridge Gaucher register with a coding for hip replacement were included in the study. Demographic and operative data were recorded from the patient notes and radiographical analysis was conducted. Hip scores were obtained via telephone interview.
Introduction
The Metasul articulation was introduced in the early 1990's. It comprises a 28mm forged, cobalt-chrome head and a forged metal inlay, set into the polyethylene element of the acetabular component. During the 1990's and early 2000's anatomic sized MoM articulations were re-introduced for hip resurfacing and stemmed implant designs. Adverse tissue reactions to metal debris and corrosion products subsequently led to a decline in MoM usage.
Materials & Methods
Between January 1995 and December 1998, 133 hips underwent primary THR using the Metasul 28mm bearing. Patients were routinely sent an annual postal Oxford Hip Score (OHS) and radiographs were obtained from the second post-operative year. We have retrospectively reviewed the clinical and radiographic dataset following the 15 year follow-up time point.
Introduction
Cross linked polyethylene (XLPE) has gained popularity as a bearing surface of choice for younger patients despite only medium term results being available for wear rates. Concern remains regarding the long-term stability and durability of these materials. In order to address these issues we present the longest radiological and clinical follow-up of XLPE.
Patients/Materials & Methods
Since 1986, we have prospectively studied a group of 17 patients (19 hips) that underwent a cemented Charnley low friction arthroplasty using a combination of 22.225mm alumina ceramic femoral head, a modified Charnley flanged stem and a chemically cross-linked polyethylene cup. We now report the 28 year clinical and radiological results.
Introduction
We report on the outcome of a cemented flanged acetabular component at a minimum of 10 years post-operatively.
Patients/Materials & Methods
Two hundred and three hips were reviewed in 194 consecutive patients who underwent primary total hip arthroplasty using this implant. Cases with acetabular defects requiring bone grafting were excluded. Functional and radiological data were prospectively recorded.
Introduction
The Exeter RimFit™ flanged cemented cup features ultra-highly cross-linked polyethylene and was introduced onto the market in the UK in 2010. We aimed to examine the rates of radiolucent lines observed when the Rimfit™ cup was implanted using a ‘rimcutter’ technique with the cup sitting on a prepared acetabular rim, and a ‘trimmed flange’ technique were the flange is cut so that it sits inside the prepared acetabular rim.
Patients/Materials & Methods
The radiographs of 150 (75 ‘rimcutter’, 75 ‘trimmed flange’) Rimfit™ hip replacements were critically evaluated to assess for radiolucency at the cement bone interface. This group was then compared to a historic pre-Rimfit™ cohort of 76 patients.
Introduction
Local commissioning groups are no longer funding outpatient follow up of joint replacements in an effort to save money. We present the costs of changing from traditional follow up methods to a virtual clinic at Warwick Hospital. Before September 2014 all joint replacements were seen in outpatients at six weeks, one year, five years, ten years and then every two years thereafter. They were usually reviewed, in a non-consultant led clinic, by a Band 7 specialist physiotherapist. This cost approximately £50 per patient including x-ray. Occasionally, the patients were seen in a consultant led clinic costing approximately £100.
Methods and Results
Currently patients are reviewed in outpatients at six weeks and one-year post operation by a specialist physiotherapist. Patients over the age of 75 years (at time of surgery) are then discharged to the care of their GP. Patients under the age of 75 enter the virtual clinic. They receive an Oxford Hip/Knee Score and x-ray at seven years post op then every three years after. In order to set up and maintain the virtual clinic a midpoint band 3 administrator was employed. Based on 3000 follow up episodes per year the cost of administrating the database is £7 per patient; however this will vary dependent on actual activity. The cost of a virtual appointment with a specialist physiotherapist who will review the Oxford Hip/Knee Score and an x-ray is approximately £40 including x-ray. The total cost of a virtual clinic follow up is therefore approximately £47.
Introduction
Mix and Match (M&M) describes the use of components from more than one manufacturer in a total hip replacement (THR) The NJR has records of over 90,000 instances where this practice, which is contrary to the advice of most manufacturers and regulators, has been followed.
Patients, Materials and Method
The NJR database 2003–13 was interrogated and the types of M&M were grouped using head size, bearing characteristics and use of cement.
Introduction
Deep prosthetic joint infection is a major cause of morbidity. Previous work has shown that infected skin scales shed by members of staff in the operating theatre are the key source of infection. Much attention has been given to the design of ultra clean operating theatres but remarkably little attention has been given to factors controlling skin scale shedding.
The aim of this study was to develop a novel method of direct visualisation and quantification of skin scales and to assess the effect of a simple skin care regimen on skin scales.
Patients/Materials & Methods
Direct visualisation of the skin surface at high power is difficult due to the depth of surface contours in relation to microscope depth of field. A Zeiss stereo compound Axio-Zoom microscope was used containing a stage on which subjects’ upper or lower limbs could be comfortably placed. A reflected light source allowed direct visualisation of a magnified image of the skin surface. Real-time digital manipulation of multiple z-stacked images on a linked computer created a composite three dimensional image of the skin surface. Density of skin scales was then calculated from this image.
We tested the effect of a standardised skincare regime consisting of washing, exfoliation and moisturisation on skin scale density at multiple sites and contralateral controls.
Introduction
Hip and knee replacements are predictable orthopaedic procedure with excellent clinical outcomes. Discharging or leaking wounds affect length of hospital stay, affect bed planning and predispose to superficial and potentially deep wound infection. Predictable wound healing therefore remains the first hurdle. This trial aims to study the effectiveness of portable disposable incisional negative pressure wound therapy (NPWT) dressings in hip and knee replacements.
This trial aims to study the effectiveness of portable disposable incisional negative pressure wound dressings in hip and knee replacements and the impact on wound healing, length of stay and wound complications.
Patients/Materials & Methods
Following ethical approval 110 patients each were randomised to ‘Control group’ and ‘Study group’. Patients in control group received traditional dressings and those in study group received an incisional NPWT (PICO) manufactured by Smith & Nephew. Post operatively, state of the wound, level of wound exudate, length of hospital stay and complications were documented.
Introduction
Surgical site infection (SSI) remains a concern following total hip arthroplasty (THA). We aimed to identify risk factors for post-operative SSI in THA.
Patients/Materials & Methods
All primary THAs performed in our institution during 2009–2010 were included, giving 1832 cases in 1716 patients. Cohort demographics were mean age 67.9 years (SD10.2), mean BMI 29.6 (SD5.3), 60% female and 90.2% primary indication of osteoarthritis. Post-operative SSI within one year was identified either through hospital infection control records or from Information Services Division (NHS Scotland). Demographic and peri-operative data for known or suspected risk factors for SSI were collected from clinical records. Groups were compared using independent t-tests and chi-squared tests as appropriate.
Introduction
Severe osteolysis of the femur secondary to aseptic loosening in hip arthroplasty, remains a difficult revision scenario. Multiple techniques have been developed to aid the surgeon, including restoration of bone stock with impaction bone grafting or strut allografts, various distal fixation prostheses and mega-prostheses. Cemented femoral components, with integration of the cement into the cavitations, has largely fallen out of favour. We examined the long-term outcomes with this technique.
Patients/Materials & Methods
Between 1977 and 1990, 109 patients had a cemented stem revision (without bone grafting) for severe femoral osteolysis in the absence of infection. Severe osteolysis was defined as cavitation in a minimum of 4 Gruen zones. Follow-up included functional scoring, radiological assessment and any complications. Further revision and survivorship analysis for stem failure or aseptic loosening of the femoral component were recorded.
Introduction
Cement in cement revision with preservation of the original cement mantle has become an attractive and commonly practised technique in revision hip surgery. Since introducing this technique to our unit we have used two types of polished tapered stem. We report the clinical and radiological outcomes for cement in cement femoral revisions performed using these prostheses.
Materials and Methods
All patients who underwent femoral cement in cement revision with a smooth tapered stem between 2005 –2013 were assessed. Data collected included indication for revision surgery and components used. All patients were followed up annually. Outcomes recorded were radiographic analysis, clinical outcome scores (Oxford Hip Score, WOMAC and SF-12) and complications, including requirement for further revision surgery. Median follow-up was 5 years (range 1 – 8 years).
116 revision procedures utilising cement in cement femoral revision were performed in the 8 year study period (68 females, 48 males, and mean age of 69 years). The femoral component was a C-stem AMT (Depuy) in 59 cases and Exeter stem (Stryker) in 57 cases.
Introduction
The number of total hip replacements taking place across the UK continues to grow. In an ageing population, with people living longer and placing greater strain on their prostheses, the number of peri-prosthetic femoral fractures is increasing. We studied the economic impact this has on a large university teaching hospital.
Method
All patients with a peri-prosthetic femoral fracture between 24/11/2006 and 31/5/2014 were identified using theatre databases. Radiographic and case note analysis was performed for each case. Costings from finance department for implants and in-patient stay were obtained.
