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Introduction
Post-operative gait abnormalities are recognized following total hip arthroplasty (THA). Despite global improvement in functional outcome, gait abnormality persists for a decade or more. In this study 3-dimensional gait analysis (3DGA) was performed using a portable system with Inertial Measurement Units (IMUs) to quantify this abnormality.
Methods
The gait of 55 patients with monarthrodial hip arthrosis was measured pre-operatively and at one year post-surgery. Patients with medical co-morbidity or other conditions affecting their gait were excluded. Six IMUs were aligned at the level of the anterior superior iliac spines, mid-thigh and mid-leg. Data was analysed using proprietary software. Each patient underwent a conventional THA using a posterolateral approach. 92 healthy individuals were assessed for comparison.
Introduction
The majority of primary total hip arthroplasty (THA) procedures performed throughout the world use modular junctions, such as the trunnion-head interface; however, the failure of these press-fit junctions is currently a key issue that may be exacerbated by the use of large diameter heads. Several factors are known to influence the strength of the initial connection, however, the influence of different head sizes has not previously been investigated. The aim of the study was to establish whether the choice of head size influences the initial strength of the trunnion-head connection.
Methods
Ti-6Al-4V trunnions (n = 60) and two different sizes of Co-Cr heads (28 mm and 36 mm) were used in the study. Three different levels of assembly force were considered; 4, 5 and 6 kN (n = 10 each). The strength of the press-fit connection was subsequently evaluated by measuring the pull-off force required to break the connection. Finite element and analytical models were also developed to better understand the mechanics of the problem.
Introduction
Dual-mobility bearings increase the stable range of motion of total hip arthroplasty (THA) but are limited by the mechanical effects of a large diameter metal on polyethylene bearing which may cause high rates of wear from the surfaces of the polyethylene bearing and the head-stem taper. Improved polyethylene (PE) has reduced concern over bearing wear but the effects on the taper junction are unknown.
We aimed to better understand the effect of dual mobility bearings on fretting-corrosion damage to the taper junction by comparison to standard bearings.
Materials and Methods
We collected and analysed retrieved hips of one design with either dual mobility (n= 39) or standard bearings (n=30). The bearing size in the dual mobility group was 42mm whereas in the standard bearing group it had a median of 36mm. Stem trunnions had V40 tapers. Time of implantation and body mass index were comparable between the two groups.
Fretting and corrosion at the stem trunnions was quantified by: 1) visual scoring and 2) surface profilometry.
Introduction
Historical studies have reported incidences of taper corrosion in retrieved MoP hips of 20–50%. These studies relied on visual assessments, rather than using modern analytical techniques.
Patients/Materials and Methods
The Northern Retrieval Registry was initiated to routinely analyse all retrieved hips. The volumetric wear rates of retrieved Exeter head tapers were measured using a coordinate measuring machine using validated methods and compared to the available results obtained from an ongoing study of failed MoM prostheses. Power analysis suggested that we would need at least fifty Exeter head tapers to provide significant results. Non-parametric tests were used to assess differences. We have previously identified head diameter/offset/taper angle and taper surface roughness as variables associated with taper wear. The effect of bearing material combination remains unquantified. These design variables were entered into a multiple regression model following log normalisation of taper wear.
Introduction
Although DDH is one of the most common skeletal dysplasias (incidence 1.5 cases per 1000 births), it remains slow and costly to recruit large-scale patient cohorts for powerful genetic association studies. In this work we have successfully used the NJR as a platform to generate a DDH biobank of 907 individuals, upon which we have conducted the first ever genome-wide association study (GWAS) for DDH.
Methods
5411 patients recorded as having a hip replacement for ‘hip dysplasia’ between March 2003 and December 2013 were approached to participate in the study. Following filtering by questionnaire for non-DDH cases and non-European Caucasians, 907 patients returned a completed saliva sample. A randomly selected sample of individuals participating on the UK Household Longitudinal Study that had been previously genotyped using the same platform were used as controls at a case:control ratio of 1:4. A further data set consisting of 332 cases, 1375 controls and 26 variants was used to replicate the top signals.
Introduction
The biological pathways responsible for adverse reactions to metal debris (ARMD) are unknown. Necrotic and inflammatory changes in response to Co-Cr nanoparticles in periprosthetic tissues may involve both a cytotoxic response and a type IV delayed hypersensitivity response.
Our aim was to establish whether differences in biological cascade activation exists in tissues of patients with end-stage OA compared to those with aseptic loosening of a metal on polyethylene (MoP) THR and those with ARMD from metal-on-metal (MoM) THR.
Patients & Methods
A microarray experiment (Illumina HT12-v4) was performed to identify the range of differential gene expression between 24 patients across 3 phenotypes: Primary OA (n=8), revision for aseptic loosening of MoP THR (n=8) and ARMD associated with MoM THR (n=8).
Results were validated using Taqman Low Density Array (TLDA) selecting the top 36 genes in terms of fold-change (FC)>2 and a significant difference (p<0.05) on ANOVA.
Pathways of cellular interaction were explored using Ingenuity IPA software.
Background
Some reports have suggested that debris generated from the head neck taper junction is more destructive than equivalent doses from metal bearing surfaces.
Methods
Part 1. We examined the relationship between the source (taper/bearing) and volume of metal debris on Cr and Co concentrations in corresponding blood and hip synovial fluid samples and the observed agglomerated particle sizes in excised tissues using regression analysis of prospectively collected data at a single revision unit. Part 2. We investigated variables most strongly associated with macroscopic soft tissue injury as documented at revision surgery using ordinal logistic regression. Independent variables included source and volume of CoCr exposure, Cr and Co joint fluid concentrations, joint fluid grade, ALVAL (Aseptic Lymphocytic Vasculitis Associated Lesion) grade, presence of vascular hyalinisation, agglomerated particle size, implant type, patient sex and age.
Using a femoral head from one manufacturer on the stem of another manufacturer poses the risk that the taper interface between the components do not contact correctly and the performance of the joint will be impaired. The cohorts in this study are a combination of modular Birmingham Hip Resurfacing (BHR) and Adept femoral heads on CPT stems. The study reviews the geometry of the taper interfaces to establish if the taper clearance angles was outside of the normal range for other taper interfaces. In addition the rates of material loss from the bearings and taper and a ranking of the stem damage were reviewed to determine if the levels of loss were above that seen for other similar joints.
The material loss analysis demonstrated that the rates or levels of loss from the bearings, taper and stem are no different to levels published for manufacturer matched joints and in many cases are lower. The results demonstrate that the taper clearance angles for the mixed manufacturer joints (BHR-CPT: 0.067 to −0.116, Adept-CPT: 0.101 to −0.056) were within the range of other studies and manufacturer matched clearances (0.134 to −0.149).
Using components from different manufacturers has not in this instance increased the level of material loss from the joints, when compared to other similar manufacturer matched joints.
As a result of laser imaging studies in an ultraclean theatre we concluded that obstructions to horizontal airflow at the periphery might produce areas of high particulate residence times. High residence times may allow a higher proportion of infected particles to land. We decided to investigate this effect by placing settle plates in defined positions on instrument trays during surgery.
In an initial study contamination was 0.25 colonies/plate/hour. When the surgeon, assistant and scrub person all used a body exhaust system the contamination rate was 0.04 colonies/plate/hour. We then organised the instrument tables with two large tables orientated so that the scrub person did not have to stand between the airflow and the table. We placed plates on both trays with the locations recorded.
With the instrument trolleys in optimised positions the contamination rate remained consistently at 0.04 colonies/plate/hour. An animation was produced showing how the bacterial colonies appeared over 18 hours of surgery. The majority of the contamination occurred on the surgeons’ side trolley at the opposite end of the trolley to the surgeon.
Ultraclean enclosures in the UK are specified by HTM03-01, which sets a standard of <10 cfu/cubic meter measured by active air sampling. The measurement does not however take place during surgery, as it is very difficult to perform air sampling during surgery. There is a reasonable correlation between air contamination and settle plates so they are a viable method for during surgery monitoring.
In a modern operating enclosure, using body exhausts, our contamination rate compares favourably to the fourth phase of Charnley's classic study in which he used 300 air changes/hour in the prototype closure. The rate compares favourably to the multi-centre Italian GISIO-ISChIA study. The contamination rate achieved could form a basis for comparative audits based on realistic during surgery monitoring.
Introduction
Tantalum trabecular metal components are increasingly used to reconstruct major bone defects in revision arthroplasty surgery. It is known that some metals such as silver have antibacterial properties. Recent reports have raised the question as to whether Tantalum components are protective against infection in revision surgery. This is based on a retrospective, single institution review, of revision cases comparing tantalum with titanium acetabular implants, which reported a lower incidence of subsequent infection in the tantalum group.
This laboratory study aimed to establish if tantalum had any intrinsic antibacterial properties against planktonic bacteria or ability to inhibit biofilm formation.
Materials and methods
Equal sized pieces of tantalum (Trabecular metal, Zimmer UK) and titanium (Trilogy, Zimmer UK) were sterilised and then incubated with a low dose inoculum of either Staphylococcus aureus or Staphylococcus epidermidis for 24 hours. After serial dilution, colony forming units were quantified on MH agar plates.
To establish the ability to inhibit biofilm formation these tantalum and titanium pieces were then washed twice, sonicated and washed again to remove loosely adhered planktonic bacteria. They were then re-incubated for 24 hours prior to quantifying colony forming units.
All experiments were performed in triplicate
Introduction
Radiological Inclination (RI) is defined as the angle formed between the acetabular axis and the longitudinal axis when projected onto the coronal plane. Higher RI angles are associated with adverse outcomes.
Methods
Primary aim: to investigate the effect of adjusting patient pelvic position in the transverse plane by using a ‘head-down’ (HD) operating table position. This was to determine, when aiming for 35° Apparent Operative Inclination (AOI), which operating table position most accurately achieved a target post-operative RI of 42°.
N=270. Patients were randomised to one of three possible operating table positions:
0°HD (Horizontal),
7°HD, or
Y°HD (Patient Specific Table Position)
Operating table position was controlled using a digital inclinometer. RI was measured using EBRA software.
Introduction
In total hip arthroplasty (THA), a high radiographic inclination angle (RI) of the acetabular component has been linked to an increased dislocation rate, liner fracture, and increased wear. In contrast to version, we have more proven boundaries when it comes to a safe zone for angles of RI. Although intuitively it seems easier to achieve a target RI, most studies demonstrate a lack of accuracy and the trend towards a high RI with all surgical approaches when using a freehand technique or a mechanical guide. This is due to pelvic motion during surgery, which can be highly variable.
The current study had two primary aims, each with a different primary outcome. The first aim was to determine how accurate a surgeon could obtain the target operative inclination (OI) during THA when using a cementless cup using a digital protractor. The second aim was to determine how accurate a surgeon can estimate the target OI to obtain a RI of 40° based on the patient's hip circumference as demonstrated in a previous study.
Methods
In this prospective study, we included 200 consecutive patients undergoing uncemented primary THA in the lateral decubitus position using a posterior approach. Preoperatively, the surgeon determined the target OI based on the patient's hip circumference (22.5°, 25°, 27.5° or 30°). Intraoperatively, the effective OI was measured with the aid of a digital inclinometer after seating of the acetabular component. Six weeks postoperatively anteroposterior pelvic radiographs were made and two evaluators, blinded to the effective OI, measured the RI of the acetabular component. The safe zone for inclination was defined as 30°-45° of inclination.
Introduction
Outcomes following large joint arthroplasty are influenced by the accuracy of implant placement. Patient specific (PS) technology has been used in knee arthroplasty surgery however, its application in total hip arthroplasty remains relatively unexplored.
Aims
We investigated whether conventional or PS guides, resulted in a more accurate reconstruction of the pre-operative head centre position.
INTRODUCTION
Dislocation is a major complication post total hip replacement (THR) and a common cause for revision. Jameson et al (2012) studied 35,000 cemented Exeter (Stryker) THRs demonstrating the risk of revision was significantly influenced by the acetabular component design. This led 3 surgeons in a single hospital group to make a mass move from using the hooded Exeter Low Profile (LP) cup to the better performing Contemporary Flanged (CF) component. The purpose of this study was to show whether this change was associated with a fall in dislocation rates.
PATIENTS/MATERIALS & METHODS
Locally held National Joint Registry data between 2010 and 2015 was used to ascertain implants used in all primary THRs by 3 experienced high volume surgeons. This was linked to local Hospital Episode Statistics to identify patients who had undergone closed or open reduction of a dislocated hip replacement in theatre.
Introduction
Previous systematic reviews have shown that patients experience low physical activity levels following total hip replacement (THR). However no previous systematic reviews have examined the changes between pre- and post-operative physical activity levels.
Methods
AMED, MEDLINE, EMBASE, CENTRAL, CINHAL, openSIGLE,
Introduction
This analysis determined whether the type and level of physical activity changes during the initial 24 months post-total hip (THR) or total knee replacement (TKR) compared to pre-operative levels, and how this change compares to people without arthroplasty or osteoarthritis.
Patients/Materials & Methods
Data from a prospective cohort dataset (Osteoarthritis Initiative dataset) of community-dwelling individuals who had undergone a primary THR or TKR were identified. These were compared to people who had not undergone an arthroplasty and who did not have a diagnosis of hip or knee osteoarthritis during the follow-up period (control). Data were analysed comparing between-group and within-group differences for physical activity (gardening, domestic activities, sports, employment, walking) within the first 24 months post-arthroplasty.
Introduction
The mortality and serious side effects risk of both medical and surgical management of hip and knee osteoarthritis (OA) has been widely published. To date however, there are no studies comparing safety between the two treatment modalities. We aimed to systematically review the published evidence on the mortality and serious complications risk of the various treatments for hip and knee OA.
Methods
We searched for studies investigating the safety of arthroplasty, arthroscopy, opioids, non-steroidal anti-inflammatory drugs (NSAIDS), and paracetamol using PubMed, Score, Cochrane, PEDRO, and Google Scholar. The phrase “osteoarthritis treatment” was searched and then combined using Boolean connectors (“OR and “AND) with “serious complications” or “serious adverse events” or “mortality”. The quality of included studies was assessed based on the approach used by the AAOS in judging the quality of treatment studies.
Image-guided intra-articular hip injection of local-anaesthetic and steroid is commonly used in the management of hip pain. It can be used as a diagnostic and/or therapeutic tool and is of low cost (£75). The aim of this study was to assess how often a hip injection has a therapeutic effect.
This is a retrospective, consecutive, case series of intra-articular hip injections performed in a tertiary referral hospital over a 2-year period (2013–4). Patients were identified from the radiology department's prospectively entered database. Clinical information, reason for injection and subsequent management was obtained from hospital records. All patients prospectively reported their pain levels in a numeric pain scale diary (out of 10) at various time points; pre-, immediately post-, 1st day-, 2nd day- and 2 weeks- post-injection. Only patients with complete pain scores at all time points were included (n=200, of the 250 injections performed over study period, 80%).
The majority of injections were performed for osteoarthritis (OA) treatment (82%). The pain was significantly reduced from a pre-injection score of 7.5 (SD:2) to 5.0 (SD:3) immediately post-injection(p<0.001); only 24 (11%) reported any worsening of pain immediately post-injection. Pain significantly reduced further to 3.8(SD:3) at 2-weeks post-injection (p<0.001). 50% of patients had at least a 3 point drop in reported pain. No improvement was seen in 18 patients and 10 (5%) reported worse pain at 2-weeks compared to pre-injection. Of the OA cohort, 10% have required repeat injections, 45% required no further intervention and 45% underwent or are due for hip replacement. No immediate complications occurred.
Intra-articular hip injection reduced pain in 86% of cases and has delayed any further surgical treatment for at least 2 years in over 50% of OA cases. It is hence a cost-effective treatment modality. Further work is necessary to describe factors predicting response.
Introduction
THR is one of the most frequently performed operations nationally. A large number of prostheses are available, and the procedure is therefore associated with variation in practice and outcomes. NICE guidelines aim to standardise best practice, and are informed by separate, independent bodies, such as the NJR and ODEP, which monitor data about the implants used and their performance. This study aims to determine whether clinical practice and component use has changed since the publication of NJR data.
Methods
NJR reports from 2006–2014 were analysed, with record made of the different prostheses used in THR, noting ODEP ratings of components used. Analysis was also performed by component type (i.e. cemented and cementless stems and cups), and combinations of components, according to their frequency of use in a given year. The Kruksal-Wallis test was used for statistical analysis.
Introduction
Orthopaedic theatres can be noisy.
Noise exposure is known to be related to reduced cognition, reduced manual dexterity and increased rates of post-operative wound infection. Up to 50% of orthopaedic theatre staff have features of Noise-Induced Hearing Loss (NIHL) with higher levels in consultants compared to registrars. Exposure to noise levels of 90dB(A) at work for a career of 40 years, equates to a 51% risk of hearing loss.
Materials & methods
A Casella CEL-242 meter was positioned in the corner of the theatre tent. Recordings were taken for 17 Total Knee Replacements (TKRs) and 11 Total Hip Replacements (THRs). This meter recorded the decibel level once per second (whereas EU Regulation requires equivalent continuous level measurement).
Introduction
We investigated whether blood metal ions could effectively identify bilateral metal-on-metal hip patients at risk of adverse reactions to metal debris (ARMD).
Patients and methods
This single-centre, prospective study involved 235 patients (185 bilateral Birmingham Hip Resurfacings (BHRs) and 50 bilateral Corail-Pinnacles) undergoing whole blood metal ion sampling (mean time=6.8 years from latest implant to sampling). Patients were divided into ARMD (revised or ARMD on imaging; n=40) and non-ARMD groups (n=195). Metal ion parameters (cobalt; chromium; maximum cobalt or chromium; cobalt-chromium ratio) were compared between groups. Optimal metal ion thresholds for identifying ARMD patients were determined using receiver operating characteristic (ROC) analysis, which compares the performance of different tests using the area under the curve (AUC) (higher AUC=more discriminatory).
Introduction
The Birmingham Hip Resurfacing (Smith & Nephew London, UK) is the most popular hip resurfacing (HR) in the UK. However, it is now subject to two Medical Device Alerts (MDA) from the Medicines and Healthcare products Regulatory Agency (MHRA).
Patients/Materials & Methods
A cross-sectional survey of primary metal-on-metal hip procedures recorded on the National Joint Registry for England, Wales and Northern Ireland (NJR) until 5th November 2013 was performed.
Cost-analysis was based on an algorithm for surveillance of HR at a tertiary referral centre and followed previous MHRA guidance. NIHR NHS Treatment costs were used.
The local protocol encompassed: patient outcome scoring (Oxford hip score), blood metal ion measurement (cobalt, chromium), cross-sectional imaging (MRI) and discussion at an internet-enabled multidisciplinary team meeting (iMDT) in addition to routine hip surveillance.
Introduction
In the early 2000s hip resurfacing became an established bone conserving hip arthroplasty option particularly for the fit and active patient cohort. The performance of second-generation metal-on-metal bearings had led to the reintroduction of hip resurfacing. The Birmingham Hip resurfacing (BHR) was introduced in 1997. This was followed by a number of different designs of the hip resurfacing. The Durom hip resurfacing was introduced in 2001. These two designs had different metallurgical properties, design parameters particularly clearance and different implantation techniques. Data from joint registries show that both prosthesis perform well.
Objectives
Our objective was to perform a retrospective survival analysis comparing the Birmingham to the Durom hip resurfacing and analyse the mode of failures of the cases revised.
Introduction
The impact of pseudotumours associated with metal-on-metal hip resurfacings (MoMHRs) within the second decade is unknown. We investigated: (1) the incidence and risk factors for all-cause and pseudotumour revision following MoMHR at 15-years follow-up, and (2) whether risk factors were gender specific.
Patients and methods
This single-centre prospective cohort study included 1429 MoMHRs (1216 patients; 40% female) implanted between 1999–2009. All patients were contacted in 2010 and 2012 as per national recommendations. Patients with hip problems and/or suboptimal Oxford Hip Scores (<41/48) underwent cross-sectional imaging and blood metal ion sampling. Revisions were performed as indicated with diagnoses confirmed from operative and histopathological findings. Multi-variate Cox proportional hazard models assessed the association of predictor variables on time to all-cause and pseudotumour revision.
Introduction
Surgical simulation and ‘virtual’ surgical tools are becoming recognised as essential aids for speciality training in Trauma & Orthopaedics, as evidenced by the BOA T&O Simulation Curriculum 20131,2. The current generation of hip arthroplasty simulators, including cadaveric workshops, offers the trainee limited exposure to reproducible real life bony pathology. We developed and implemented a novel training course using pathological dry bone models generated from real patient cases to support senior orthopaedic trainees and new consultants in developing knowledge and hands on skills in complex total hip arthroplasty.
Patient/Materials & Methods
A two-day programme for 20 delegates was held at a specialist centre for hip arthroplasty. Three complex femoral and three complex acetabular cases were identified from patients seen at our centre. 3D models were printed from CT scans and dry bone models produced (using a mold-casting process), enabling each delegate to have a copy of each case at a cost of around £30 per case per delegate (Figure 1). The faculty was led by 4 senior Consultant revision hip surgeons. A computerised digitising arm was used to measure cup positioning and femoral stem version giving candidates immediate objective feedback (Figure 2). Candidate experience and satisfaction with the course and models was evaluated with a standardised post-course questionnaire.
Press-fit fixation of uncemented acetabular components is increasingly being used for total hip replacement (THR) surgery. This study was aimed to analyse the survival of an established, un-cemented flexible metal backed cup with non-highly cross-linked polyethylene in primary and simple revision THR.
We assessed the outcome of 1703 consecutive cementless elastic acetabular cups (Atlas, FH France) with non-highly cross-linked polyethylene (GUR1030) in total hip replacement surgery. There were 1582 patients (513 males and 1079 females) with mean age of 74 years (36–97 years). Seventeen senior operating surgeons accounted for 88.5% of cases from a single arthroplasty unit. Survival analysis was calculated using the Kaplan Meier Estimator. At 184 months post surgery the survivorship was 92.4% (95% CI 88.3–94.7) with cup revision for any cause as an endpoint. Three patients died within first month of surgery and 268 patients (17.13%) died due to unrelated causes.
Overall, 59 patients had revisions (3.5%), Thirty eight patients (2.3%) were due to acetabular causes such as: aseptic loosening in 6 patients (0.35%); hip instability in 13 patients (0.76%); and deep infection in 11 patients (0.64%).
We believe the cementless elastic acetabular cup on in total hip replacement is tolerant of technique and patient variation and continues to give excellent long-term results and its continued widespread use can be recommended.
Introduction
A recent paper suggested implanting an uncemented acetabular shell which is 6mm or greater than the native femoral head in total hip arthroplasty (THA) significantly increased the risk of postoperative pain. We retrospectively analyzed 265 Delta ceramic-on-ceramic (DCoC) THA comparing the native femoral head size to the implanted shell and reviewing if the patient suffered with post-operative pain (POP).
Methods
265 consecutive THAs were performed using the Corail and Pinnacle prostheses with DCoC bearing. Native femoral head size was calculated retrospectively on pre-operative radiographs using TraumaCad software. All patients were sent questionnaires requesting information on satisfaction, sounds, postoperative pain and complications. Statistical analysis was then undertaken on the data.
Functional scores are used to clinically assess total hip arthroplasty (THA) and for comparative purposes in orthopaedic literature. Previous pilot work has highlighted patient comorbidity as a potential source of bias in addition to the often-examined factors of age, gender and underlying diagnosis.
We analysed prospectively collected data relating to 217 primary THAs (Tayside Arthroplasty Audit Group database). Sample size was calculated from previous pilot data (significance level 5%, power 80%, effect size 0.25). Proportional stratified sampling was performed including all patient age groups (≤40, 41–55, 56–65, >65) and four fixation classes (cemented, hybrid, uncemented and Birmingham resurfacing). Five year Harris Hip Function Score (HHFS) was the dependent variable; age, sex, underlying diagnosis, BMI, pre-operative HHFS and comorbidity (Functional Comorbidity Index; range 0–8) were co-variates/co-factors.
In univariate analysis, FCI accounted for 11% of the variation in HHFS at 5 years. Regarding patients with FCI 0–1 as a reference group, patients with greater comorbidity had lower HHFS at 5 years (FCI 2–3: −3.95; FCI 4–5: −7.21, FCI ≥6: −6.92). In a multivariable model of HHFS at 5 years, FCI group, diagnosis, pre-operative HHFS, patient age and BMI were significant. HHFS at 5 years was significantly higher in FCI group 0–1 than any other category (2–3 P=0.006, 4–5 P<0.001, ≥6 P=0.002). In total, the model accounted for 29% of variability in HHFS at 5 years.
This is the first statistically robust study to examine the effect of comorbidity on THA function. These results strongly suggest that increasing patient comorbidity is associated with poorer THA function when measured using HHS.
Two significant conclusions can be drawn:
Patient comorbidity should be taken into account pre-operatively when considering potential future THA function. When comparing across implants, failure to give specific consideration to comorbidity of patient groups will limit relevance and weight of findings.
Introduction
Primary hip replacement in young active patients is on the increase. Due to the demands set by the patient, implants used in this patient group should have a proven long-term clinical and radiological outcome. We report our results in patients under the age of 50 using the C-Stem femoral component – a cemented triple tapered polished stem.
Methods
Since the C-stem femoral component was introduced into clinical practice in 1993, 6906 C-stems have been used in primary hip replacements at our hospital. In this group, 896 patients were under the age of 50 at the time of surgery. We report the first 300 consecutive C-stems from this group. The surgical technique of using a bone block to allow subsidence and clearing of the calcar to increase loading of the proximal femur medially was routinely used together with a femoral cement gun and pressurizer.
Introduction
Data on the outcome of THA in patients under the age of 30 years is sparse. There is a perceived reluctance to offer surgery to young patients on the basis of potential early failure of the implant. We aim to review our experience with THA in this group of patients to establish outcomes in a high volume specialist arthroplasty unit.
Material & methods
A retrospective review of prospectively collected data from the Lower Limb Arthroplasty Unit of patients who underwent THA <30 years of age between 1989–2009 was undertaken. Ninety five patients (117 THAs) were identified but 25 patients (27 hips) were excluded for lack of clinical records and 6 patients (9 hips) for follow up of <5 years. Clinical records were reviewed for patients’ age at operation, underlying pathology, details of operation and any failures (revision). Radiographs were reviewed for any evidence of loosening and wear of the components. Functional assessment was also carried out using the modified Hip disability & osteoarthritis outcome score (HOOS), Oxford hip score and EQ5D–5L.
Introduction
The Exeter Hip femoral component remains largely unchanged from the original design, introduced in 1970. It is a highly polished, modular, double tapered stem and has undergone various minor modifications to surface, modularity and most recently the taper; changed to the current V40TM design in 2000.
The effect of any design modification cannot easily be foreseen and greater emphasis is now placed on ensuring appropriate monitoring for such implants.
Methods
We present the results of the first 540 V40TM Exeter THAs performed in our Centre between December 2000 and May 2002. All patients were reviewed prospectively at 1, 5 and 10 years following surgery.
Introduction
The Corail stem is a fully HA coated tapered implant that has demonstrated long-term success. On the NJR it has become one of the most commonly used implants in the UK. The aim of our study was to document our experience of the revision of this implant together highlighting some important technical considerations.
Patients/Materials & Methods
A retrospective review of a consecutive case series of revision procedures where the Corail stem was extracted. We considered time since implantation, collared or uncollared design, indication for revision, Paprosky classification of femoral deficiency, endo-femoral reconstruction or extended approach/osteotomy, subsequent reconstruction either further primary type implant (cemented or cementless) or revision femoral implant.
Introduction
Limb Length discrepancy after total hip replacement has been reported to happen in 1–27% of cases with differences up to 70mm. Occasionally revision THR has been used to achieve limb length equalisation, especially when patients are symptomatic with hip/back pain, neurologic symptoms or instability. However, in presence of a well-functioning, pain free hip without hip symptoms, revision THR for shortening can lead to problems with decrease in offset or stability. An option in these cases would be a distal shortening osteotomy of femur.
Materials and Methods
From 2005 to 2014 five shortening osteotomies were done for LLD with limb lengthening of ipsilateral side following THR. All patients had well-functioning THRs with and no complications as dislocations or nerve symptoms.
A distal metaphyseal shortening osteotomy, fixed using a 95 degree blade plate, was chosen for better healing at this level and ease of surgery.
Introduction
The results of cementless total hip arthroplasty (THA) vary with data from the UK national Joint Registry being less favourable than that from the Australian registry. The senior author started using a fully cementless THA in 2005 and we aimed to gauge the performance of the implants based on their revision data.
Patients and methods
Between August 2005 and March 2015, 4,802 primary THA (4,309 patients) were performed with a cementless Corail® stem and a cementless Pinnacle® cup. There were 2,086 (43.4%) males and 2,716 (56.6%) females with a median age of 70 years (IQR 13, Range 16–95). There were a number of changes to the surgical technique with respect to the Corail® stem during the ten-year period, which we have categorised as phase 1 and phase 2. We compared the data in the two phases. Data were extracted from a prospectively maintained patient information database.
Background
An extended trochanteric osteotomy (ETO) is a widely used approach for revision hip arthroplasty. Following an ETO it is common practice to use a long stemmed femoral prosthesis at the second stage to bypass the osteotomy. We propose that at the second stage, if the osteotomy has united, it is appropriate to use a standard length prosthesis, which preserves bone stock for any future revisions.
Methods
We performed a retrospective review of our institution's prospective arthroplasty database, identifying all patients who had undergone an ETO at the first stage revision. A radiograph review was then performed and any subsequent complications recorded. A selection of patients radiographs were individually reviewed by three reviewers and intra-class correlation (ICC) was performed to assess intra-observer reliability.
Introduction
Between 2005 and 2010, the number of revision hip arthroplasties rose by 49.1%, and revision knee arthroplasties by 92.1%. This number is predicted to rise by 31% and 332% respectively by 2030.
In March 2014, NHS England invited bids to run a pilot revision network. Nottingham Elective Orthopaedic Service (NEOS) was successful and the East Midlands Specialist Orthopaedic Network (EMSON) runs on a ‘hub-and-spoke’ model.
Patients/Materials & Methods
All patients within the EMSON area requiring revision arthroplasty are discussed at a weekly meeting. The meeting is chaired by a revision hip and knee surgeon and attended by arthroplasty surgeons and an orthopaedic microbiologist. Other specialties are available as required.
EMSON discussions and a proposed management plan are recorded, signed by the Chair and returned as a permanent record in the patient's notes.
Introduction
The removal of a well fixed cement mantle for revision of a total hip replacement (THR) can be technically challenging and carries significant risks. Therefore, a cement-in-cement revision of the femoral component is an attractive option.
The Exeter Short Revision Stem (SRS) is a 125 mm polished taper stem with 44 mm offset specifically designed for cement-in-cement revisions. Only small series using this implant have been reported.
Patients/Materials & Methods
Records for all patients who had undergone a cement-in-cement revision with the SRS were assessed for 1) radiological femoral component loosening 2) clinical femoral component loosening 3) further revision of the femoral component 4) complications.
We assessed serial radiographs for changes within the cement mantle and for implant subsidence.
Introduction
Stem revision with retention of the old cement mantle (cement-in-cement revision) in cases with an intact cement/bone interface is an appealing option. There has been an increasing use of this technique. In 2014 this cement-in- cement technique was used in 10% of all stem revisions reported to the Swedish Hip Arthroplasty Register (SHAR). We analysed the outcome of cement-in-cement stem revisions reported to the SHAR during years 2001–2014
Patients/Materials & Methods
Since 2001 1292 cement-in-cement revisions (study group), performed with a short (≤150 mm) Exeter stem (n=973) or a Lubinus stem (n=319) were reported to the SHAR. Stem revisions, using short Exeter and Lubinus stems without the use of the cement-in-cement technique (n=2893) acted as the control group in this analysis. Both groups were comparable regarding primary diagnosis. In the study group there were more females and the mean age (73 years) was 2 year older (p<0.001). The primary outcome was re-revision due to all causes (n=413). Re-revision of the stem due to all causes, infections excluded (n=212) was used as secondary outcome. Survival analysis using Kaplan-Meier was performed.
Introduction
Revision of well cemented femoral components in revision THA can be technically challenging and time consuming. The cement in cement (CiC) technique addresses these issues. Results of femoral components which have undergone multiple CiC revisions have not previously been reported.
Objective
We present the clinical and radiological results of femoral components which have undergone multiple CiC revisions with a minimum follow up of 5 years.
Introduction
Large acetabular bone defects caused by aseptic loosening are common. Reconstruction of large segmental defects can be challenging. Various implants and operative techniques have been developed to allow further acetabular revision in cases where bone stock is poor. Reconstitution of bone stock is desirable especially in younger patients. The aim of the study was to review the clinical and radiological results of hip revision with structural acetabular bone grafts using fresh frozen allograft and cemented components.
Method
Between 1990 and 2014, 151 first time revisions for aseptic acetabular loosening with acetabular reconstruction with a fresh frozen structural allograft and cemented components were performed at our hospital.
Graft dimensions, number of screws used and socket coverage by the graft were measured on the post-operative AP radiograph.
Follow-up radiographs were analysed for socket loosening, quality of graft union, graft and graft resorption.
Introduction
Dislocation as a primary cause of revision has been on the increase in Sweden (14% in 2014). The increasing use of Dual Mobility cups (DMC) could well be explained by the increased revision burden due to dislocation, patients undergoing revision having increased comorbidities and reports that dual articular cup designs reduce the risk of dislocation. The aim of this study was to analyze the change in utilization pattern of the dual articular designs used in acetabular revision surgery in Sweden. The short-term survival of DMC was compared to traditional designs.
Patients/Materials & Methods
During years 2004–2014, 1111 (925 cemented) revisions performed with a DMC design were reported to SHAR. About half (n=426) of these cases were first time revisions performed due to dislocation. During the same time period 520 dislocations were revised for dislocation using a standard cemented cup. There was no differences regarding the age, gender and primary diagnosis (p≥0.12) between the two groups. A second cup revision for all reasons and specifically for dislocation was used as end-point. Kaplan-Meier analysis was performed.
Introduction
Acetabular revision surgery is becoming more prevalent with an estimated increase of 137% by 2030. It is challenging surgery especially in the presence of deficient bone loss. Several techniques of acetabular reconstruction are used world-wide. The greater the bone loss (Paprosky Type IIIA and IIIB, and AAOS Classification of Acetabular Bone Loss Type 3 and 4) the more complex are the reconstruction methods. There is however, insufficient literature comparing the contemporary techniques of revision acetabular reconstruction and their outcomes.
Objectives
The purpose of this study was to systematically review the literature and to report clinical outcomes and survival of contemporary acetabular revision arthroplasty techniques (tantalum metal (TM) systems, uncemented revision jumbo cups, reinforced devices such as cages and rings, oblong cups and custom-made triflange cups). We specifically looked at outcomes when reconstruction was undertaken in the presence of bone loss.
Background
Sub-trochanteric fractures are challenging to treat due to various anatomical and biomechanical factors. High tensile forces contribute to the challenge of fracture reduction. Intramedullary nailing has become the treatment of choice. If anatomical reduction is not achieved, any mal-alignment will predispose to implant failure. Open reduction with cerclage wires can add to construct stability and improve the quality of reduction. There is no consensus or classification to guide surgeons on when to perform open reduction, which is often performed intra-operatively when closed reduction fails often with no planning. This can lead to intraoperative delays as theatre staff would not have prepared the correct equipment necessary for open reduction
Objectives
The purpose of this study was to assess outcomes of closed and open reduction of traumatic sub-trochanteric fractures treated with intramedullary nailing and to propose a new classification system to dictate management.
Introduction
Reoperation within thirty days after hip fracture surgery is associated with increased mortality, length of stay and cost of care. The United Kingdom National Hip Fracture Database (NHFD) reported a significant increase in the 30-day reoperation rate for patients undergoing surgery for hip fractures in our unit from 2012 to 2014. We audited our data in order to validate this and identify any reversible trends.
Methods
Between January 2012 and December 2014, 1757 consecutive procedures for hip fracture were performed in our unit. Patients who had a reoperation within 30 days and those recorded as ‘unknown’ under the reoperation category were identified. Patients with hip dislocations were included. Patient demographics, diagnosis, treatment and outcomes were recorded. This was compared with reoperation for all causes after 30 days over a 12-month period.
National Institute of Clinical Excellence (NICE) recommended total hip replacement (THR) surgery for fit patients with fracture neck of femur (NOF) in 2011. Our hospital implemented hip fracture program to follow these recommendations the same year. However, the increased incidence of further procedures compared with those undergoing the THR for osteoarthritis alone has led to concern regarding dislocation and other complications when using THR treatment for fracture NOF particularly with the posterior approach.
We introduced dual mobility implant for THR for hip fracture program patients to minimize risk of hip instability but allowing the use of the posterior approach which is recognised as giving a faster recovery than the Hardinge type approaches in this patient group. The Arthroplasty database for hip fracture program was reviewed from September 2011 to September 2015 for appropriateness of this treatment. During this period, 120 Dual Mobility THRs were carried out in 119 patients (36 males, 84 females) with mean age at 78 years (42–94) and average follow-up of 24 months (2–56 months). All patients were either operated by a fellowship trained arthoplasty surgeons or the senior surgeons using posterior approach. All patients undergoing THR for NOF were found to meet the NICE guidelines criteria for THR. No post-operative dislocation, infection, hetotropic ossification or lysis was recorded. Mean Harris Hip Score (HHS) at 19 months was 82 (54–98). In this cohort 112 patients (94.3%) were able to ambulate in non-trendlenburg gait pattern. One patient developed deep vein thrombosis in early post-operative period.
This study emphasises beneficial use the dual mobility implant combined with the posterior approach in THR for fracture NOF patients and highlights the areas of improvements in hip fracture management.
Introduction
Periprosthetic fractures of the femur are potentially catastrophic injuries associated with significant morbidity and mortality. Surgical treatment comprises revision arthroplasty or internal fixation. It is well established that a delay in treating patients with hip fracture leads to higher mortality rates, however there is limited evidence regarding mortality rates and the time to surgery in patients with lower limb periprosthetic fractures.
Aim
This study was done to assess if delay to surgery affected the mortality rates in patients with periprosthetic fractures of hip and knee.
The management of proximal femoral bone loss is a significant challenge in revision hip arthroplasty. A possible solution is the use of a modular proximal femur endoprosthesis (EPR). Although the survivorship and functional outcome of megaprostheses used in tumour surgery has been well described, outcome of EPRs used in revision hip surgery has received less attention. The aim of this study was to determine the 5-year outcome following proximal femur EPR and determine factors that influence it.
This was a retrospective consecutive case series of all EPRs (n=80) performed for non-neoplastic indications, by 6 surgeons, in our tertiary referral centre, between 2005–2014. Patient demographics and relevant clinical details were determined from notes. The most common indications for the use of EPRs included infection (n=40), peri-prosthetic fracture (n=12) and failed osteosynthesis of proximal femoral fractures/complex trauma (n=11). Outcome measures included complication and re-operation rates, implant survival and assessment of functional outcome using the Oxford-Hip-Score (OHS).
The mean age at surgery was 69 years and mean follow-up was 4 (0 – 11) years. The mean number of previous hip operations was 2.4 (range: 0 – 17). Twenty-five patients sustained a complication (31%), the most common being infection (n=9) and dislocation (n=4). By follow-up, further surgery was required in 18 (22%) hips, 9 of which were EPR revisions. 5-yr implant survivorship was 87% (95%CI: 76 – 98%). Mean OHS was 28 (range: 4 – 48). Inferior survival and outcome were seen in EPRs performed for the treatment of infection. Infection eradication was achieved in 34/41 with the index EPR procedure and in 40/41 hips by follow-up.
Limb salvage was achieved in all cases and acceptable complication- and re-operation rates were seen. EPRs for periprosthetic fractures and failed osteosynthesis had best outcome. We recommend the continued use of proximal femur EPR in complex revision surgery.
Introduction
Patients with asymptomatic bacteriuria (ASB) have a significantly increased risk of both superficial wound infection and deep infection following arthroplasty. Debate continues as to whether treatment of pre-operative ASB reduces the risk of subsequent prosthetic joint infection.
Patients/Materials & Methods
All arthroplasty units in Scotland were contacted by telephone and asked a standard series of questions regarding pre-operative urine testing in arthroplasty patients. A review of the literature was also performed.
Introduction
Native hip joint infection can result in hip arthrosis as a complication requiring the need for subsequent arthroplasty. There is little evidence to support single or staged THA. We present the results of patients who have undergone total hip arthroplasty (THA) following hip joint sepsis in our institution.
Methods
Patients receiving a THA following previous hip joint sepsis between 2003 and 2015 were identified from the operative records database. Further clinical information was collected from the medical records, including timing of infection and surgery, as well as culture results. Functional outcome (Oxford Hip Score, OHS) and patient satisfaction scores (PSS) were recorded.
Introduction
Prosthetic joint infections (PJIs) generate significant clinical and socio-economic pressures on the health service. Recent advances in the diagnosis of PJIs, with biomarkers and sonification have aided delineation of PJIs from aseptic processes. However these investigations are not widely available and expensive. Interface membrane histology has been shown to be superior to pseudocapsule histology; we therefore sought to ascertain the diagnostic benefit of deep canal sample microbiology in conjunction with standard pseudocapsule sampling.
Patients/Materials & Methods
We performed a prospective study over a 20-month period as part of new multi-disciplinary approach to the management of suspected PJIs. 22 patients underwent 26 procedures at our institution where intra-operative deep canal samples were obtained concurrent to conventional pseudocapsule samples. These samples were cultured and analysed following our standardised microbiological methodology.
Introduction
Vancomycin is commonly added to acrylic bone cement during revision arthroplasty surgery. Proprietary cement preparations containing vancomycin are available but significantly more expensive. We investigated whether the antibiotic elution and mechanical strength of ‘home-made’ vancomycin containing bone cement was comparable to commercial vancomycin-impregnated cement.
Methods
A total of 18 cement discs of constant size, containing either proprietary CopalG+V®; or ‘home-made’ CopalR+G® with vancomycin added by hand, were made. Each disc contained the same antibiotic quantities (0.5g gentamycin, 2g vancomycin) and was immersed in ammonium acetate buffer in a sealed container. Fluid from each container was sampled at eight time points over a two week period. The concentration of gentamicin and vancomycin in the fluid was analysed using high performance liquid chromatography mass spectrometry. The impact strength of each PMMA cement preparation was measured using a Charpy-type impact tester.
Introduction
The value of Debridement-Antibiotics-and-Implant-Retention (DAIR) in prosthetic-joint-infection (PJI) is still a matter of debate as most studies to-date are underpowered with variable end-points. In our, tertiary referral, bone infection unit we consider DAIR to be a suitable option in all PJIs with soundly fixed prostheses, despite chronicity. The aims of this study were to define the long-term outcome following DAIR in hip PJI and identify factors that influence it.
Methods
This is a retrospective consecutive case series of DAIRs performed between 1997 and 2013. Only infected cases confirmed by established criteria were included. Data recorded included patient demographics, medical history (ASA grade, Charlson and KLICC scores), type of surgery performed (DAIR or DAIR + exchange of modular components) and organism grown. Outcome measures included complications, implant survivorship and functional outcome (Oxford Hip Score, OHS).
