Exeter Hip Unit

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Research outputs from the Exeter Hip Unit team. You can also follow Exeter Hip Unit on Twitter and Facebook.


Recent Submissions

Now showing 1 - 5 of 60
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    Survival of the Exeter V40 short revision (44/00/125) stem when used in primary total hip arthroplasty
    (British Editorial Society of Bone and Joint Journal, 2023-05-01) Evans, J. T.; Salar, O.; Whitehouse, S. L.; Sayers, A.; Whitehouse, M. R.; Wilton, T.; Hubble, M. J. W.
    The Exeter V40 femoral stem is the most implanted stem in the National Joint Registry (NJR) for primary total hip arthroplasty (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 patient anatomy requires a smaller stem with a 44 mm offset. We aimed to investigate survival of this implant in comparison to others in the range when used in primary THAs recorded in the NJR. We analyzed 328,737 primary THAs using the Exeter V40 stem, comprising 34.3% of the 958,869 from the start of the NJR to December 2018. Our exposure was the stem, and the outcome was all-cause construct revision. We stratified analyses into four groups: constructs using the 44/00/125 stem, those using the 44/0/150 stem, those including a 35.5/125 stem, and constructs using any other Exeter V40 stem. In all 328,737 THAs using an Exeter V40 stem, the revision estimate was 2.8% (95% confidence interval (CI) 2.7 to 2.8). The 44/00/125 stem was implanted in 2,158 primary THAs, and the ten-year revision estimate was 4.9% (95% CI 3.6 to 6.8). Controlling for age, sex, year of operation, indication, and American Society of Anesthesiologists grade demonstrated an increased overall hazard of revision for constructs using the 44/00/125 stem compared to constructs using other Exeter V40 femoral stems (hazard ratio 1.8 (95% CI 1.4 to 2.3)). Although the revision estimate is within the National Institute for Health and Care Excellence ten-year benchmark, survivorship of constructs using the 44/00/125 stem appears to be lower than the rest of the range. Adjusted analyses will not take into account 'confounding by indication', e.g. patients with complex anatomy who may have a higher risk of revision. Surgeons and patients should be reassured but be aware of the observed increased revision estimate, and only use this stem when other implants are not suitable.
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    Clinical and cost effectiveness of single stage compared with two stage revision for hip prosthetic joint infection (INFORM): pragmatic, parallel group, open label, randomised controlled trial
    (BMJ, 2022-10-31) Blom, A. W.; Lenguerrand, E.; Strange, S.; Noble, S. M.; Beswick, A. D.; Burston, A.; Garfield, K.; Gooberman-Hill, R.; Harris, S. R. S.; Kunutsor, S. K.; Lane, J. A.; MacGowan, A.; Mehendale, S.; Moore, A. J.; Rolfson, O.; Webb, J. C. J.; Wilson, M.; Whitehouse, M. R.
    OBJECTIVES: To determine whether patient reported outcomes improve after single stage versus two stage revision surgery for prosthetic joint infection of the hip, and to determine the cost effectiveness of these procedures. DESIGN: Pragmatic, parallel group, open label, randomised controlled trial. SETTING: High volume tertiary referral centres or orthopaedic units in the UK (n=12) and in Sweden (n=3), recruiting from 1 March 2015 to 19 December 2018. PARTICIPANTS: 140 adults (aged ≥18 years) with a prosthetic joint infection of the hip who required revision (65 randomly assigned to single stage and 75 to two stage revision). INTERVENTIONS: A computer generated 1:1 randomisation list stratified by hospital was used to allocate participants with prosthetic joint infection of the hip to a single stage or a two stage revision procedure. MAIN OUTCOME MEASURES: The primary intention-to-treat outcome was pain, stiffness, and functional limitations 18 months after randomisation, measured by the Western Ontario and McMasters Universities Osteoarthritis Index (WOMAC) score. Secondary outcomes included surgical complications and joint infection. The economic evaluation (only assessed in UK participants) compared quality adjusted life years and costs between the randomised groups. RESULTS: The mean age of participants was 71 years (standard deviation 9) and 51 (36%) were women. WOMAC scores did not differ between groups at 18 months (mean difference 0.13 (95% confidence interval -8.20 to 8.46), P=0.98); however, the single stage procedure was better at three months (11.53 (3.89 to 19.17), P=0.003), but not from six months onwards. Intraoperative events occurred in five (8%) participants in the single stage group and 20 (27%) in the two stage group (P=0.01). At 18 months, nine (14%) participants in the single stage group and eight (11%) in the two stage group had at least one marker of possible ongoing infection (P=0.62). From the perspective of healthcare providers and personal social services, single stage revision was cost effective with an incremental net monetary benefit of £11 167 (95% confidence interval £638 to £21 696) at a £20 000 per quality adjusted life years threshold (£1.0; $1.1; €1.4). CONCLUSIONS: At 18 months, single stage revision compared with two stage revision for prosthetic joint infection of the hip showed no superiority by patient reported outcome. Single stage revision had a better outcome at three months, fewer intraoperative complications, and was cost effective. Patients prefer early restoration of function, therefore, when deciding treatment, surgeons should consider patient preferences and the cost effectiveness of single stage surgery. TRIAL REGISTRATION: ISRCTN registry ISRCTN10956306.
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    Obesity alone should not rule out knee replacement surgery
    (BMJ, 2022-10-25) Saul, H.; Gursul, D.; Evans, J.
    The studyEvans JT, Mouchti S, Blom AW, et al. Obesity and revision surgery, mortality, and patient-reported outcomes after primary knee replacement surgery in the National Joint Registry: a UK cohort study. PLoS Med 2021;18:7.
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    The use of a modified posterior approach (SPAIRE) may be associated with an increase in return to pre-injury level of mobility compared to a standard lateral approach in hemiarthroplasty for displaced intracapsular hip fractures: a single-centre study of the first 285 cases over a period of 3.5 years
    (Springer, 2022-07-25) Charity, J.; Ball, S.; Timperley, A. J.
    BACKGROUND AND PURPOSE: A tendon-sparing modification of the posterior approach to the hip joint was introduced in the specialist hip unit at our institution in 2016. The SPAIRE technique-acronym for Saving Piriformis And Internus, Repair of Externus" preserves the insertions of gemellus inferior, obturator internus, gemellus superior and piriformis intact. We compare the results of the first 285 hip hemiarthroplasty patients, unselected but preferentially treated by our hip unit surgeons using the SPAIRE technique, with 567 patients treated by all orthopaedic surgeons (including the hip unit) in the department over the same 3.5 year period using the standard lateral approach. We report length of stay, return to pre-injury level of mobility, place of residence and mortality at 120 days. PATIENTS AND METHODS: The review included all hemiarthroplasty patients. Pre-fracture mobility and place of residence, surgical approach, grade of senior surgeon in theatre, stem modularity, acute and overall length of stay, mobility, place of residence, re-operations and mortality at 120 days were recorded. Data were obtained from the National Hip Fracture Database that included a telephone follow-up at 120 days and from electronic patient records. RESULTS: The odds of returning to pre-injury level of mobility were higher in the SPAIRE technique group than in the standard lateral group; adjusted odds ratio (95% confidence interval (CI)) 1.7 (1.1 to 2.7, p = 0.01). INTERPRETATION: When used in hip hemiarthroplasty, the SPAIRE technique appears safe and may confer benefit in maintaining the pre-injury level of mobility over the standard lateral approach."
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    Use of computerised adaptive testing to reduce the number of items in patient-reported hip and knee outcome scores: an analysis of the NHS England National Patient-Reported Outcome Measures programme
    (BMJ, 2022-07-20) Evans, J. P.; Gibbons, C.; Toms, A. D.; Valderas, J. M.
    OBJECTIVE: Over 160 000 participants per year complete the 12-item Oxford Hip and Knee Scores (OHS/OKS) as part of the NHS England Patient-Reported Outcome Measures (PROMs) programme. We used a modern computational approach, known as computerised adaptive testing (CAT), to simulate individually tailored OHS and OKS assessment, with the goal of reducing the number of questions a patient must complete without compromising measurement accuracy. METHODS: We fit the 2018/2019 PROMs data to an item response theory (IRT) model. We assessed IRT model assumptions alongside reliability. We used parameters from the IRT model with data from 2017/2018 to simulate CAT assessments. Two simulations were run until a prespecified SE of measurement was met (SE=0.32 and SE=0.45). We compared the number of questions required to meet each cut-off and assessed the correlation between the full-length and CAT administration. RESULTS: We conducted IRT analysis using 40 432 OHS and 44 714 OKS observations. The OHS and OKS were both unidimensional (root mean square error of approximation 0.08 and 0.07, respectively) and marginal reliability 0.91 and 0.90. The CAT, with a precision limit of SE=0.32 and SE=0.45, required a median of four items (IQR 1) and two items (IQR 1), respectively, for the OHS, and median of four items (IQR 2) and two items (IQR 0) for the OKS. This represents a potential 82% reduction in PROM length. In the context of 160 000 yearly assessments, these methodologies could result in the omission of some 1 280 000 redundant questions per year, which equates to 40 000 hours of patient time. CONCLUSION: The application of IRT to the OHS and OKS produces an efficient and substantially reduced CAT. We have demonstrated a path to reduce the burden and potentially increase the compliance for these ubiquitous outcome measures without compromising measurement accuracy.