In metal-on-metal (MoM) hip replacements or resurfacings, mechanical induced corrosion can lead to a local inflammatory response, pseudo tumours and elevated serum metal ions, requiring revision surgery.

The size and diametral clearance of Anatomic (ADM) and Modular (MDM) Dual Mobility bearings matches that of certain MOM components. Presenting the opportunity for revision with exchange of the metal head for ADM/MDM bearings without removal of the acetabular component if it is well-fixed and appropriately positioned.

Between 2012 and 2020, across two centres, 94 patients underwent revision of a MoM hip replacement or resurfacing. The mean age was 65.5 (33–87) years. In 53 patients (56.4%), the acetabular component was retained, and dual mobility bearings were used (DM); in 41 (43.6%) the acetabulum was revised (AR). DM was only considered where the acetabular component was satisfactorily positioned and well-integrated into bone, with no surface damage. Patients underwent clinical and radiographic follow-up to at least one-year (mean 42.4 (12–96) months).

One (1.1%) patient died before one-year, for reasons unrelated to the surgery. In the DM group, two (3.8%) patients underwent further surgery; one (1.9%) for dislocation and one (1.9%) for infection. In the AR group, four (12.2%) underwent further procedures; two (4.9%) for loosening of the acetabular component and two (4.9%) following dislocations. There were no other dislocations in either group. In the DM group, operative time (68.4 v 101.5 mins, p<0.001), postoperative drop in haemoglobin (16.6 v 27.8 g/L, p<0.001), and length of stay (1.8 v 2.4 days, p<0.001) were significantly lower. There was a significant reduction in serum metal ions postoperatively in both groups (p<0.001 both Cobalt and Chromium) although there was no difference between groups for this reduction (p=0.674 Cobalt; p=0.186 Chromium).

In selected patients with MoM hip arthroplasty, where the acetabular component is well-fixed, in a satisfactory position and there is no surface damage, the metal head can be exchanged for ADM/MDM bearings with retention of the acetabular prosthesis. Presenting significant benefits through a less invasive procedure, and a low risk of complications, including dislocation.

Venous thromboembolism (VTE) is a preventable cause of morbidity and mortality in patients undergoing elective hip arthroplasty surgery. The balance of post-operative VTE prophylaxis and risk of post-operative haemorrhage remains at the forefront of surgeon's mind. The National Institute for Clinical Excellence (NICE) has altered their prophylaxis guidance in the setting of total hip arthroplasty (THA). The aim of this study was to present the VTE incidence in 8,890 patients who underwent total hip arthroplasty between January 1997 and March 2018 with Aspirin as the primary agent for pharmacological thromboprophylaxis.

Analysis of prospective data collection from consecutive patients undergoing THA was performed with the incidence of deep vein thrombosis (DVT) and pulmonary embolism (PE) occurring within 6 months of the index operation as the primary outcome measure. 90-day all-cause mortality of this cohort of patients was also analysed.

8890 patients were reviewed. This included 7235 primary, 224 complex primary and 1431 revision cases. The incidence of DVT was 0.64% after elective THA and the incidence of PE was 0.54%. There was no difference in the incidence between primary and revision cases. The 90-day all-cause mortality was 0.88%. Cardiovascular and respiratory disease were the main causes of death following surgery. Only 0.03% of deaths (n= 3) within 90 days of index surgery were due to VTE.

Our results support the use of aspirin as an effective form of prophylaxis against VTE following THA. It is not associated with an increased incidence in symptomatic DVT, PE or death compared to other published studies. The fact that it is inexpensive, readily available, requires no monitoring and does not pose an increased risk of bleeding are other attractive advantages of using aspirin for VTE prophylaxis.

The aim of this study was to systemically review the evidence for the use of intra-operative cell salvage (ICS) among patients undergoing revision hip arthroplasty, and synthesis the available data to quantify any associated reduction in allogeneic blood transfusion.

An electronic database search of MEDLINE (PubMed), EMBASE, Scopus and the Cochrane Library was completed from the date of inception to 9^th February 2021, using a search strategy and protocol created in conjunction with the PRISMA statement. Inclusion criteria were (i) adult patients >18 years, (ii) ICS utilised in one study group, (iii) revision hip arthroplasty performed. Exclusion criteria were (i) pre-donation of red blood cells, (ii) mixed reporting without dedicated subgroup analysis for revision hip arthroplasty. Screening for eligibility, and quality assessment of included studies, was performed independently by two authors (TW and DH), and any disputes settled by third author (AK).

Of the 187 records identified, 11 studies were included in the qualitative analysis, and 5 studies suitable for quantitative meta-analysis. Across the included studies there were 1856 participants, with a mean age of 63.86 years and a male: female ratio of 0.90. Quality assessment demonstrated low or medium risk of bias only. For revision hip arthroplasty patients receiving ICS, 37.07% required ABT with a mean transfusion of 1.92 units or 385ml per patient. For patients treated without ICS, 64.58% required ABT with a mean transfusion of 4.02 units or 803ml per patient. This difference achieved statistical significance (p < 0.05).

This study has demonstrated a significant reduction in the need for allogenic blood transfusion associated with intra-operative cell salvage use among patients undergoing revision hip arthroplasty. This study therefore supports the routine use of ICS in this patient group. However, a major limitation is the lack of clinical outcomes reported by the available studies. Further research is required to determine whether this effect is associated with sub-groups of revision arthroplasty procedure, and whether ICS impacts clinical outcomes such as length of stay, rehabilitation progress and mortality.

The MAKO Robotic arm is a haptic robotic system that can be used to optimise performance during total hip arthroplasty (THA). We present the outcome of the first 40 robotic cases performed in an NHS foundation trust along with the technique of performing robotic THA in our unit.

Forty consecutive patients undergoing robotic THA (rTHA) were compared to a case matched group of patients undergoing manual THA (m-THA). 2:1 blinded case matching was performed for age, sex, implants used (Trident uncemented socket and cemented Exeter stem, Stryker Mahwah, NJ, US) and surgeon grade. Comparisons were made for radiological positioning of implants, including leg length assessment, and patient reported functional outcome (PROMS). Pre- and post-operative radiographs were independently analysed by 2 authors.

All patients underwent THA for a primary diagnosis of osteoarthritis. No significant difference between groups was identified for post-operative leg length discrepancy (LLD) although pre-operatively a significantly higher LLD was highlighted on the MAKO group, likely due to patient selection. Significantly lower post-operative socket version was identified in the MAKO cohort although no difference in post-operative cup inclination was noted. However, there was significantly larger variance in post-op LLD (p=0.024), cup version (p=0.004) and inclination (p=0.05) between groups indicating r-THA was significantly less variable (Levene's test for homogeneity of variance). There was no significant difference in the number of cases outside of Lewinnek's ‘safe’ zone for inclination (p=0.469), however, there were significantly more cases outside Lewinnek's ‘safe’ zone for version (12.5% vs 40.3%, p=0.002) in the m-THA group.

We report the commencement of performance of MAKO robotic THA in an NHS institution. No problems with surgery were reported during our learning curve. Robotic THA cases had less variability in terms of implant positioning suggesting that the MAKO robot allows more accurate, less variable implant positioning with fewer outliers. Longer term follow-up of more cases is needed to identify whether this improved implant positioning has an effect on outcomes, but the initial results seem promising.

The Exeter V40 femoral stem is the most implanted stem in the NJR for primary THA. In 2004, the 44/00/125 stem was released for use in “cement-in-cement” revision cases. It has however been used ‘off-label’ as a primary stem when, for example, patient anatomy requires a smaller stem with a 44mm offset. We aimed to investigate survival of this stem in comparison to others in the range when used in primary THAs recorded in the NJR.

Analyses were performed using a dataset based on that used for the 2020 NJR annual report. Our exposure was the stem; the outcome was all-cause construct revision. Crude analyses were performed using Kaplan-Meier and adjusted using Cox models. The 44/00/125 stem was directly compared to other stems in the Exeter range.

We analysed 330,732 primary THAs using the Exeter V40 stem comprising 34.5% of the 958,869 THAs with complete information from the start of the NJR to 31 December 2018. The 44/00/125 stem was implanted in 2,158 primary THAs with 67.5% in female patients and a mean age of 67.8. The 10-year revision estimate for the 44/00/125 stem was 4.9% (95%CI 3.6, 6.8) and in constructs using an Exeter V40 stem was 2.8% (95%CI 2.7, 2.8). Controlling for age, sex and ASA demonstrated an increased overall hazard of revision for constructs using the 44/00/125 stem compared to constructs using other Exeter V40 femoral stems (HR 1.8 (95%CI 1.4, 2.3)).

Although the revision estimate is within the NICE 10-year benchmark, survivorship of constructs using the 44/00/125 stem appears to be lower than the rest of the Exeter V40 range. Attempts to control for age, sex and ASA will not take into account confounding by indication i.e. patients with more complex anatomy who may have a higher risk of revision. Surgeons and patients should be reassured by this but should be aware of the observed increased revision estimate and use the stem according to its indications.

Femoral cement-in-cement revision is a well described technique to reduce morbidity and complications in hip revision surgery. Traditional techniques for septic revision necessitate removal of all bone cement from the femur. In our two institutions, we have been using a cement-in-cement technique, leaving the distal femoral cement in selected cases for septic hip revision surgery.

Between February 2010 and September 2019, 89 patients with prosthetic hip infection underwent first or single stage procedures leaving the distal femoral cement in situ and performing a cement-in-cement revision. The mean patient age was 72.0 years (24–92). The median time from the last arthroplasty procedure was 29.0 months (1–294).

81 patients underwent revision using a cemented Exeter stem, 7 patients received an articulating spacer, and one patient underwent excision arthroplasty with the distal cement left in situ. Patients received clinical and radiographic follow-up with a mean of 42.8 months (range 11.0–120.1 months). Oxford hip scores were collected from each institution's existing databases.

9 patients (10.1%) died within one year of surgery. No deaths were directly related to joint infection or the surgery. One patient was lost to follow up before one year.

Of the remainder, 7 patients (8.9%) required further procedures for infection and were therefore considered to be treatment failures. 6 patients (7.6%) underwent planned second stage procedures with no recurrence of infection. 7 patients (8.9%) had further surgery for non-infective reasons. The Kaplan-Meier estimate of infection free survival at one year was 93.7% (95% CI 88.4 to 99.0%).

No patients underwent revision for stem loosening. Oxford hip scores were available at over one year postoperatively for 51 patients with a mean score of 30.6, and a mean gain of 11.9.

In our combined cohort of patients, cement-in-cement revision had an infection eradication rate of 91.1%. Patient selection is crucial, and the procedure can only be performed when there is a well-fixed cement mantle. However, when strict criteria are followed, this technique offers potential significant benefits to surgeons performing this challenging surgery, and more importantly the patients undergoing them.

Total hip replacements (THRs) provide pain relief and improved function to thousands of patients suffering from end-stage osteoarthritis, every year. Over 800 different THR constructs were implanted in the UK in 2017. To ensure reliable implants are used, a NICE revision benchmark of 5% after 10 years exists. Given the 10-year cumulative mortality of patients under 55 years of age receiving THRs is only 5% and that a recent study suggests 25-year THR survival of 58%, we aim to produce revision estimates out to 30 years that may guide future long-term benchmarks.

The local database of the Princess Elizabeth Orthopaedic Centre (PEOC), Exeter, holds data on over 20,000 patients with nearly 30-years follow-up with contemporary prostheses. A previous study suggests that the results of this centre are generalisable if comparisons restricted to the same prostheses. Via flexible parametric survival analysis, we created an algorithm using this database, for revision of any part of the construct for any reason, controlling for age and gender. This algorithm was applied to 664,761 patients in the NJR who have undergone THR, producing a revision prediction for patients with the same prostheses as those used at this centre.

Using our algorithm, the 10-year predicted revision rate of THRs in the NJR was 2.2% (95% CI 1.8, 2.7) based on a 68-year-old female patient; well below the current NICE benchmark. Our predictions were validated by comparison to the maximum observed survival in the NJR (14.2 years) using restricted mean survival time (P=0.32). Our predicted cumulative revision estimate after 30 years is 6.5% (95% CI 4.5, 9.4). The low observed and predicted revision rate with the prosthesis combinations studied, suggest current benchmarks may be lowered and new ones introduced at 15 and 20 years to encourage the use of prostheses with high survival.

Introduction

Varus alignment of the femoral component in total hip arthroplasty (THA) is thought to be a risk factor for implant loosening and early revision surgery. The purpose of this study was to evaluate whether the Exeter stem tolerates varus alignment and assess if this theoretical malalignment has an influence on clinical outcomes.

Introduction

Rationing of orthopaedic services is increasingly being used by Care Commissioning Groups (CCG) within the United Kingdom to restrict the numbers of patients being referred for Total Hip Arthroplasty (THA). In Devon, only patients with an Oxford Hip Score (OHS) less than 20 are referred on for specialist Orthopaedic Review. The aim of this study was to look at long term outcomes after THA to see if this rationing has any rational base to justify its use

Cement-in-cement femoral revision is a proven technique in revision total hip arthroplasty, with excellent results when using standard sized Exeter stems. The Exeter 44/00 125 mm short revision stem was introduced in 2004 to facilitate cement-in-cement revision. The stem is 25mm shorter and has a slimmer body to allow greater flexibility to adjust depth of insertion and version of the stem. However, it is not known if this change in stem length and size effects its longer term performance. We therefore reviewed the clinical outcome and survival of the Exeter 44/00 short stem used for cement-in-cement revision in our unit, with a minimum of 5 years follow up.

166 cases were performed between 2004 and 2010. 103 hips were available for 5 year clinical and radiological follow up, with 91 hips surviving to final review in 2017. At 5 years, 43 hips had died, 13 were revised and 7 were too frail to attend clinical review. The fate of all 166 hips were known and included in the survival analysis.

Median clinical scores improved significantly. Sixteen hips required re-revision (infection 6, loose cup 3, periprosthetic fracture 3, instability 2, stem fracture with chronic infection 1 and pain 1). Kaplan-meier survival analysis revealed 100% survival for aseptic loosening, 96.8% survival for stem failure and 88.9% survival for all causes.

This is the largest series with the longest follow up of the Exeter 44/00 short revision stem. The stem performs equally well as standard Exeter stems with regards to aseptic loosening. The single stem fracture occurred secondary to bone loss in chronic infection, highlighting the importance of providing adequate proximal support for the stem. Periprosthetic fracture occurred in 2.4% of this series of revision cases.

Larger registry-based studies may provide additional information on the performance of this stem.

Background

There is a paucity of long term data concerning the pre and postoperative patient reported function of total knee replacement. The aim of this study was to determine the mortality, implant survivorship, patient reported function and satisfaction in a cohort of 114 patients, from a single centre, who received a Kinemax total knee replacement more than 15 years ago.

Introduction

Improvements in function after THA can be evaluated using validated health outcome surveys but studies have shown that PROMs are unreliable in following the progress of individuals. Formal gait lab analysis is expensive, time consuming and fixed in terms of location. Inertial Measurement Units (IMUs) containing accelerometers and gyroscopes can determine aspects of gait kinematics in a portable package and can be used in the outpatient setting (Figure 1). In this study multiple metrics describing gait were evaluated pre- and post THA and comparisons made with the normal population

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 V40^TM 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.

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.

Purpose:

To evaluate if adding clonidine to a standard nerve root block containing local anaesthetic and steroid improved the outcome of patients with severe lumbar nerve root pain secondary to MRI proven lumbar disc prolapse.

Mortality following hip arthroplasty is affected by a large number of confounding variables each of which must be considered to enable valid interpretation.

The aim of this study was to establish whether it is possible to determine a true cause-and-effect relationship between the risk of mortality and data that are routinely collected by the NJR and to establish the degree to which variation in the mortality rate could be explained by each variable.

Relevant variables available from the 2011 NJR data setwere included in a Cox model.

We carried out two analyses:

Firstly, we conducted an analysis of data collected from the NJR data set used in preparation of the NJR's 8th Annual Report (2011) looking for an association between the variables collected and the risk of mortality.

Secondly, as social deprivation is also known to influence mortalityrates but is not routinely collected as part of the NJR data set, a further analysis was performed which included social deprivation data derived from partial postcodes.

Mortality rates in hip arthroplasty patients were lower than in the age matched population across all hip types. Age at surgery, ASA grade, diagnosis, gender, provider type, hip type and lead surgeon grade all had a significant effect on mortality. Schemper's statistic showed that only 18.98% of the variation in mortality was explained by the variables available in the NJR data set.

It is inappropriate to use Registry data to study an outcome affected by a multitude of confounding variables when these cannot be adequately accounted for in the available data set.

Introduction

We report on the outcome of a cemented flanged acetabular component at a minimum of 10 years post-operatively.

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.

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.

Introduction:

The risk for late periprosthetic fractures is higher in patients treated for a neck of femur fracture compared to those treated for osteoarthritis. It has been hypothesised that osteopenia and consequent decreased stiffness of the proximal femur are responsible for this. We investigated if a femoral component with a bigger body would increase the torque to failure in a biaxially loaded composite sawbone model.