Revision total knee replacement: A two-year review of complexity data and regional workload in South West England

BackgroundThe GIRFT report (2012) sought to address the need for sustainable orthopaedic treatment delivered through regional “networks”; the aim being improved care, decreased cost and reduced revision rate. The aims of this study were to record the number and complexity of revision total knee replacements within a regional network using a validated classification over a two-year period and audit this against National Joint Registry (NJR) records.MethodsA region-wide network model where revision TKR cases are assessed locally using the Revision Knee Complexity Classification (RKCC) and local multi-disciplinary team (MDT) was introduced. Data was collected from 8 revision centres over a two-year period using the RKCC. The case volume was audited against the NJR records.ResultsIn year 1 (01/01/2018–31/12/2018) 237 RKCC forms were collected from eight centres. 46% of R2s and 63% of R3s were carried out at the higher volume centre. 211 K2 forms were received by the NJR. In year 2 (01/01/2019–31/12/2019) 252 RKCC forms were collected. 46% of R2s and 64% of R3s were carried out at the higher volume centre. 267 K2 forms were received by the NJR.ConclusionThis is the first published set of revision knee data showing complexity percentages across a region. The RKCC has been successfully introduced into the region and this has been sustained. The findings show that a successful network has been established and majority of complex revision knee surgery is occurring in the high-volume centre. NJR data suggests that the RKCC is capturing the complexity and volume of our work accurately.     

Financial analysis of revision knee surgery at a tertiary referral centre as classified according to the Revision Knee Complexity Classification (RKCC)

BackgroundRevision total knee arthroplasty (rTKA) can be complex, with greater costs to the treating hospital than primary TKA. A rTKA regional network has been proposed in England. The aim of this work was to accurately quantify current costs and reimbursement for the rTKA service and to assess whether costs are proportional to case complexity at a tertiary referral centre within the National Health Service (NHS).MethodsA review of all rTKA performed at our institution over two consecutive financial years (2017–2019) was performed. Cases were classified according to the Revision Knee Complexity Classification (RKCC) and by mode of failure; “infected” and “non-infected”. Financial data was acquired through Patient-Level Information and Costing System (PLICS). The primary outcome was the financial difference between tariff and cost per episode. Comparisons between groups were analysed using analysis of variance and two-tailed unpaired t-test as appropriate.Results159 patients underwent 188 rTKA procedures. Length of stay and cost significantly increased between complexity groups (p < 0.0001) and for infected revisions (p < 0.0001). All groups sustained a mean deficit but this significantly increased with revision complexity (from £1,903 to £5,269 per case) and for infected revisions. The total deficit to the Trust for the two-year rTKA service was £667,091.ConclusionsThe current level of NHS reimbursement are inadequate for centres that offer rTKA and should be more closely aligned to case complexity. An increase in the most complex rTKA at major revision centres will undoubtedly place an even greater strain on the finances of these units.     

Revision knee replacement surgery in the NHS: A BASK surgical practice guideline

BackgroundRevision knee replacement (KR) is both challenging for the surgical team and expensive for the healthcare provider. Limited high quality evidence is available to guide decision-making.AimTo provide guidelines for surgeons and units delivering revision KR services.MethodsA formal consensus process was followed by BASK’s Revision Knee Working Group, which included surgeons from England, Wales, Scotland and Northern Ireland. This was supported by analysis of National Joint Registry data.ResultsThere are a large number of surgeons operating at NHS sites who undertake a small number of revision KR procedures. To optimise patient outcomes and deliver cost-effective care high-volume revision knee surgeons working at high volume centres should undertake revision KR.This document outlines practice guidelines for units providing a revision KR service and sets out: The current landscape of revision KR in England, Wales and Northern Ireland. Service organisation within a network model. The necessary infrastructure required to provide a sustainable revision service. Outcome metrics and auditable standards. Financial mechanisms to support this service model.ConclusionsRevision KR patients being treated in the NHS should be provided with the best care available. This report sets out a framework to both guide and support revision KR surgeons and centres to achieve this aim.     

Implications of the getting it right first time initiative for regional knee arthroplasty services

Study aim

The aim of this case study of regional orthopaedic practice was to estimate the potential impact of the GIRFT recommendations (iGIRFT) of minimum unit and surgeon specific volumes to orthopaedic units within the Severn Region, UK.

Provision of revision knee surgery and calculation of the effect of a network service reconfiguration: An analysis from the National Joint Registry for England,Wales, Northern Ireland and the Isle of Man

BackgroundRevision knee replacement (KR) is technically challenging, expensive, and outcomes can be poor. It is well established that increasing surgeon and unit volumes results in improved outcomes and cost-effectiveness for complex procedures. The aim of this study was to 1) describe the current provision of revision KR in England, Wales and Northern Ireland at the individual surgeon and unit level and 2) investigate the effect on workload of case distribution in a network model.MethodsCurrent practice was mapped using NJR summary statistics containing all revision KR procedures performed over a three-year period (2016–2018). Units were identified as revision centres based on threshold volumes. Units undertaking < 20 revisions per year were classified as Primary Arthroplasty Units (PAUs) in calculations on the effect of workload centralisation.ResultsRevision KR was performed by 1353 surgeons at 232 NHS sites. The majority of surgeons and units were low-volume; > 1000 surgeons performed < 7 and 125 sites performed < 20 procedures per year. Reallocation of work from these 125 PAUs (1235 cases, 21% of total workload) to a network model with even redistribution of cases between centres undertaking revision surgery would result in an additional average annual case increase of 11 per unit per year (range six to 14).ConclusionsRevision KR workload re-allocation would lift all revision centres above a 30 per year threshold and would appear to be a manageable increase in workload for specialist revision KR centres. Case complexity and local referral agreements will significantly affect the real increase in workload; these factors were not incorporated here.     

5-year cost/benefit analysis of revision of failed unicompartmental knee replacements (UKRs); not “just” a primary total knee replacement (TKR)

BackgroundA number of studies suggest that one advantage of a unicompartmental knee replacement (UKR) is ease of revision to a total knee replacement (TKR). We aimed to perform a cost/benefit analysis of patients undergoing this procedure at our centre to evaluate its economic viability.MethodsFrom our own prospective joint replacement database we identified 812 consecutive tibio-femoral UKRs performed (1994–2007) of which 23 were revised to TKR (2005–2008). These were then matched to a cohort of primary TKRs (42 patients). Data were collected regarding patient demographics, cost of surgery, clinical outcome (OKS) and follow-up costs at five years.ResultsThere was no significant difference in implant costs or in length of stay, however tourniquet time was significantly higher in the revision group (average 93 min (UKR) vs 75 min (TKR) p < 0.0001).At five years there was no significant difference in clinical outcome between the revision UKR and primary TKR groups, mean OKS 27 and 32 respectively (p = 0.20). The revision group had a greater complication and revision rate, attending significantly more follow-up appointments (average 6 (UKR) vs 2 (TKR) p < 0.0001) and consultant appointments (average 4 (UKR) vs 0.4 (TKR) p < 0.0001). This was translated to significantly higher follow-up costs.ConclusionRevision of UKR to TKR is not universally a straightforward procedure comparable to a standard primary replacement. Despite cost of components not being significantly higher than primary TKR there are multiple hidden follow-up costs. The clinical outcomes are however similar at 5 years.     

Revision knee replacement for prosthetic joint infection: Epidemiology,clinical outcomes and health-economic considerations

Prosthetic joint infection (PJI) is a devastating complication of knee replacement surgery. Recent evidence has shown that the burden of disease is increasing as more and more knee replacement procedures are performed. The current incidence of revision total knee replacement (TKR) for PJI is estimated at 7.5 cases per 1000 primary joint replacement procedures at 10 years. Revision TKR for PJI is complex surgery, and is associated to a high rate of post-operative complications. The 5-year patient mortality is comparable to some common cancer diagnoses, and more than 15% of patients require re-revision by 10 years. Patient-reported outcome measures (PROMs) including joint function may be worse following revision TKR for PJI than for aseptic indications. The complexity and extended length of the treatment pathway for PJI places a significant burden on the healthcare system, highlighting it as an area for future research to identify the most clinically and cost-effective interventions.     

Investigation and management of prosthetic joint infection in knee replacement: A BASK Surgical Practice Guideline

BackgroundThe burden of knee replacement prosthetic joint infection (KR PJI) is increasing.KR PJI is difficult to treat, outcomes can be poor and it is financially expensive and limited evidence is available to guide treatment decisions.AimTo provide guidelines for surgeons and units treating KR PJI.MethodsGuideline formation by consensus process undertaken by BASK's Revision Knee Working Group, supported by outputs from UK-PJI meetings.ResultsImproved outcomes should be achieved through provision of care by revision centres in a network model. Treatment of KR PJI should only be undertaken at specialist units with the required infrastructure and a regular infection MDT.This document outlines practice guidelines for units providing a KR PJI service and sets out:

• •The necessary infrastructure required to provide a high-quality KR PJI service
• •The MDT composition — who and when
• •The KR PJI care pathway
• •Medical and surgical treatment strategies
• •The indications for referral to tertiary units (Major Revision Centres)
• •Outcome metrics and auditable standards

ConclusionsKR PJI patients treated within the NHS should be provided the best care possible. This report sets out guidance and support for surgeons and units to achieve this.     

Are pain and function better measures of outcome than revision rates after TKR in the younger patient?

Revision is the gold standard outcome measurement for survival analyses of orthopaedic implants but reliance on revision as an endpoint has been recently questioned. This study, that assesses long-term outcome in a specific group of patients who had undergone total knee replacement (TKR) for osteoarthritis, highlights the main problems facing modern survival analyses. Minimum 12-year survival and outcome data were reviewed for a series of sixty patients under the age of 60 years (mean age 55.4 years) who underwent total knee replacement (TKR) for osteoarthritis. The patients are a subgroup from a larger consecutive series of 1429 patients who underwent TKR between 1987 and 1993 at a single institution. Whilst the main study aim was to compare outcome of TKR using different endpoints, the outcome of TKR in this younger subpopulation could also be investigated.With revision as the primary endpoint the survival for TKR was 82.2% (95% CI 17.3). The mean OKS at follow-up (mean 15.7 years) was 30.9. However, many of the 82% of patients who did not undergo revision had a less than satisfactory outcome. 41% of these patients reported modest or severe pain (using the OKS) at final follow-up. A combined endpoint including revision, poor function and significant pain drastically reduced the survival rate for the operation. Survival based on revision alone provides an acceptable but inaccurate impression of outcome in younger TKR patients (under 60 years). A true representation of the success of TKR should include pain and function as endpoints.     

Survival of the low contact stress rotating platform total knee replacement is influenced by age: 1058 implants with a minimum follow-up of 10 years

Background

The low contact stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimise polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated.The primary aim of this study was to assess long-term survivorship of the LCS TKR performed at a single high-volume centre. Secondary aims were to assess survival by mechanism of failure and identify predictors of revision.

Early outcomes using a ‘kinematic retaining’ total knee replacement – A multicentre prospective study at two years follow-up

BackgroundAlthough predictable implant longevity in total knee replacement (TKR) is now established, work continues to satisfy the demands of patients who seek full restoration of the painless function of the native knee following TKR. This prospective study examines the early clinical outcomes of 156 patients implanted with a novel ‘kinematic-retaining’ (KR) implant.Methods156 Physica KR TKRs were implanted for primary osteoarthritis at three European centres. Patients were reviewed up to two years using radiographic, clinical and functional evaluations.ResultsOf the 137 patients retained at two years’ follow up, none had been revised. Within 6 post-operative months, 51.7% and 79.9% had excellent clinical and functional KSS values respectively, increasing to 81.8% and 88.3% beyond two years. Mean KSS improvement was 34.8 (from 48.6 to 83.4). All KOOS sub-scores improved significantly with total KOOS improving from a mean of 35.5 (SD ±13.0) to 86.5 (±13.7) at two years post-operatively. Pain and sports KOOS sub-scores improved rapidly during the early post-operative periods, with sustained improvements beyond this. Mean OKS improved by 44.1 (±5.1) at two years. VAS satisfaction scores improved significantly at all time points beyond six weeks. Mean FJS-12 was 75.7 at two years, with no significant effects of age or gender. No progressive adverse radiographic features were noted.ConclusionsEarly clinical and radiographic outcomes of this kinematic-retaining knee prosthesis are promising, with improvements in clinical parameters similar to, or exceeding those published in other contemporary TKR designs.Level of evidence: II, Multicentre Prospective cohort study.     

Management of aseptic failure of the mobile-bearing Oxford unicompartmental knee arthroplasty

BackgroundUnicompartmental knee arthroplasty (UKA) accounts for 9.1% of primary knee arthroplasties (KAs) in the UK. However, wider uptake is limited by higher revision rates compared with total knee arthroplasties (TKA) and concerns over subsequent poor function. The aim of this study was to understand the revision strategies and clinical outcomes for aseptic, failed UKAs at a high-volume centre.MethodsThis was a retrospective, single-centre cohort study of 48 patients (31 female, 17 male) with 52 revision UKAs from 2006 to 2018. Median time to revision was 67 (range 4–180) months. Indications for revision were progression of osteoarthritis (n = 31 knees, 59.6%), unexplained pain (n = 10 knees, 19.2%), aseptic loosening (n = 6 knees, 11.5%), medial collateral ligament incompetence (n = 3 knees, 5.8%) and recurrent bearing dislocation (n = 2 knees, 3.8%). Technical details of surgery, complications and functional outcome were recorded.ResultsFailed UKAs were revised to primary TKAs (n = 29 knees, 55.8%), revision TKAs (n = 9 knees, 17.3%), bicompartmental KAs (n = 11 knees, 21.2%), or unicompartmental-to-unicompartmental KAs (n = 3 knees, 5.8%). Median follow up was 81 (range 24–164) months. Four patients (7.7%) died from unrelated causes. No re-revisions were identified. Surgical complications required re-operation in five knees (9.6%). Median Oxford Knee Score at latest follow up was 38 (range 9–48) points and median EQ5D3L index 0.707 (range −0.247 to 1.000).ConclusionsAseptic, revision UKA at a high-volume centre had good clinical outcomes. Bicompartmental KA demonstrated excellent function and should be considered an alternative to TKA for progression of osteoarthritis for appropriately trained surgeons.     

The effect of surgical approach in total knee replacement on outcomes. An analysis of 875,166 elective operations from the National Joint Registry for England,Wales, Northern Ireland and the Isle of Man

BackgroundTotal knee replacement (TKR) is clinically and cost-effective. The surgical approach employed influences the outcome, however there is little generalisable and robust evidence to guide practice. We compared outcomes between the common primary TKR surgical approaches.Methods875,166 primary TKRs captured in the National Joint Registry, linked to hospital inpatient, mortality and patient reported outcome measures (PROMs) data, with up to 15.75 years follow-up were analysed. There were 10 surgical approach groups: medial parapatellar, midvastus, subvastus, lateral parapatellar, ‘other’ and their minimally invasive versions. Survival methods were used to compare revision rates and 45-day mortality. Groups were compared using Cox proportional hazards regression and Flexible Parametric Survival Modelling (FPM). Confounders included age at surgery, sex, risk group (indications additional to osteoarthritis), American Society of Anesthesiologists grade, TKR fixation, year of primary, body mass index, and for mortality, deprivation and Charlson comorbidity subgroups. PROMs were analysed with regression modelling or non-parametric methods.ResultsThe conventional midvastus approach was associated with lower revision rates (Hazard Rate Ratio (HRR) 0.80 (95% CI 0.71–0.91) P = 0.001) and the lateral parapatellar with higher revision rates (HRR 1.35 (95% CI 1.12–1.63) P = 0.002) compared to the conventional medial parapatellar approach. Mortality rates were similar between approaches. PROMs showed statistically significant, but not clinically important, differences.ConclusionsThere is little difference in PROMs between the various surgical approaches in TKR with all resulting in good outcomes. However, the conventional midvastus approach (used in 3% of cases) was associated with a 20% reduced risk of revision surgery compared to the most commonly used knee approach (the conventional medial parapatellar: used in 91.9% of cases). This data supports the use of the midvastus approach and thus surgeons should consider utilising this approach more frequently. Minimally invasive approaches did not appear to convey any clinical advantage in this study over conventional approaches for primary TKR.     

Age stratified,matched comparison of unicompartmental and total knee replacement

BackgroundUnicompartmental knee replacement (UKR) tends to provide better function but has a higher revision rate than total knee replacement (TKR). The aim was to determine if this occurred in all age groups.MethodsTwo large, non-registry, prospective cohorts with median 10-year follow-up (2252 TKR, 1000 medial UKR) were identified. All UKR met recommended indications. TKR with an inappropriate disease pattern for medial UKR were excluded. Knees were propensity score-matched within age-strata (< 60 years at operation, 60 to < 75, 75 +) and compared using Oxford Knee Score (OKS), Kaplan–Meier revision rates and a composite failure, defined as any of revision, reoperation or no improvement in OKS.ResultsOne thousand five hundred and eighty-two TKR and UKR were matched. Results are reported TKR vs UKR for ages < 60, 60 to < 75 and 75 +. Median 10-year OKS were 33 vs 45 (p < 0.001), 36 vs 42 (p < 0.001) and 36 vs 38 (p = 0.25). Ten-year revision rates were 11% vs 7%, 5% vs 5%, and 5% vs 10%, (none significant). The composite failures occurred 8%, 5% and 5% more frequently with TKR than UKR (none significant).ConclusionsIn this matched study UKR provided better functional outcomes in all age groups, particularly the young, and provided substantially more excellent outcomes. Although in older groups TKR tended to have a lower revision rate, in the young UKR had a lower revision rate. This was surprising and was perhaps because in this study UKR was, as recommended, only used for bone-on-bone arthritis, whereas in young patients it is widely used for early arthritis, which is associated with a high failure rate. This study supports the use of UKR with recommended indications, in all age groups.     

Revision of Oxford medial unicompartmental knee arthroplasty to total knee arthroplasty - results of a multicentre study

The advantages of Unicompartmental Knee Replacement (UKR) over Total Knee Replacement (TKR) includes the preservation of soft tissue as well as bone stock, and better function with improved range of motion and more natural gait. It is therefore believed that the revision of failed UKR to TKR is technically easier than revision of failed TKR. In our study we tested this hypothesis by assessing the reconstruction requirements and early clinical and radiological outcome following the revision of UKR to TKR. During a 15-year period 1060 primary Oxford medial UKR procedures were performed at three centres, 36 of which underwent revision to TKR due to aseptic failure. The mean operating time for revision surgery was 113 min. Among the revision prostheses used, 28 were standard TKRs, six were constrained, and two were semi-constrained. Thirty had no intramedullary stems whereas six had intramedullary stems. In 30 cases reconstruction for bone loss was not required whereas metal augmentation was used in two knees, contained peg defects in the femur were filled with cement in two knees and contained keel defects in the tibia were grafted using the bone from revision cuts in two knees. After a mean follow-up of 2 years, the mean 'total knee score' was 86.3 and the mean functional score was 78.5. These findings suggest that the complexity of operation and complications encountered during Oxford medial UKR revision and the clinical outcome compare favorably with those of TKR revision.     

Mid-term survivorship and clinical outcomes of the Avon patellofemoral joint replacement

Background

We present the largest series of Avon patellofemoral joint (PFJ) replacements outside of the design centre. There is discussion over its efficacy and usefulness. We report an independent opinion of its indications, survivorship and outcomes.

What is the patient experience following revision knee replacement: A systematic review and meta-analysis of the medium term patient reported outcomes

AimsRevision knee replacement is an increasingly common procedure, however, information on patient-focused outcomes is limited. This systematic review and meta-analysis aimed to investigate the medium-term patient reported outcomes following a revision knee replacement.MethodsWe performed a systematic review of MEDLINE and EMBASE (from inception to 1st March 2021) for articles reporting five year or greater patient reported outcome measures (PROMs) following revision knee replacement. A meta-analysis of PROMs data was undertaken using the Standardised Mean Difference (SMD). Quality of methodology was assessed using Wylde’s non-summative four-point system. The study was registered with PROPSERO (CRD42021199289).ResultsA total of 23 studies met the inclusion criteria containing 2414 patients at a mean minimum follow-up of 74 months (60–122). The reporting of PROMs were poorly standardised with several PROMs being used. The most commonly reported patient reported outcome was the Knee Society Score reported in 65% of studies (15/23). A meta-analysis of 629 eligible patients undergoing revision knee replacement revealed a significant improvement in pre-operative state with a SMD 2·05 95% CI 0.87, 3.23.ConclusionThis systematic review has found a significant and sustained improvement in patient-reported outcomes following a revision knee arthroplasty beyond five years. We found a variation in the usage and administration of PROMs which hinders a clear synthesis of results. Furthermore, the PROMs have not been robustly tested for validity in the context of a revision knee replacement.     

Management of varicella contacts in pregnancy: VZIG or vaccination?

BackgroundVaricella infection during pregnancy poses a serious risk for both foetus and mother. It has been suggested that it would be more cost-effective to screen antenatally with post-partum vaccination, which occurs in the US, than the current policy of checking immune status post varicella exposure, with VZIG administration where necessary. Additionally, it is doubtful whether the current policy provides best patient care, when a vaccine is available.ObjectivesThe study aims to retrospectively compare the cost of the current policy with a cost estimate for antenatal screening with post-partum vaccination in NI.Study designA cost estimate of antenatal screening of primigravidas, with post-partum vaccination, was calculated for two models: (1) verbal screening, with serological testing of those with no history of varicella infection and (2) serological screening of all primigravidas.ResultsThe cost of VZIG issued to pregnant women in 2006 was £100,800; 43% of births were to primigravidas therefore the estimated cost of VZIG issued to multigravidas was £58,100. The cost of verbal screening with post-partum vaccination is estimated at £23,750 p.a., saving £34,350 over current policy.The estimated cost of screening all primigravidas with post-partum vaccination is £43,000, saving £15,100.ConclusionsThis retrospective study suggests that in NI either of the proposed antenatal screening strategies would be less costly than current practice. This finding supports the suggestion that varicella immunity testing should be included in the Antenatal Infectious Diseases Screening Programme, either as part of the universal vaccination programme or solely as an antenatal programme.     

Inferior outcomes of total knee replacement in early radiological stages of osteoarthritis

BackgroundTotal knee replacement (TKR) for osteoarthritis (OA) is a common and successful operation; the severity of radiographic changes plays a key role as to when it should be performed. This study investigates whether an early radiological grade of OA has an adverse effect on the outcome of TKR in patients with arthroscopically confirmed OA.MethodsBetween January 2006 and January 2011 data was collected prospectively on all patients undergoing a primary TKR for OA. We included all patients with a Kellgren–Lawrence score of two or less on their pre-operative radiograph who had had an arthroscopy to confirm significant OA. Our primary outcomes were the Oxford Knee Score (OKS) and a satisfaction rating.ResultsOver the study period 1708 primary TKRs were performed in 1381 patients. We identified 44 TKRs in 43 patients with a Kellgren–Lawrence score of two or less on their pre-operative radiograph. In this group the mean age was 63 years, 66% were female and the mean BMI was 31.7 kg/m². At a mean follow-up of 37 months the mean OKS was only 30 points compared to 36 in all TKRs performed over the same period (p = 0.0004). Only 68% were either satisfied or very satisfied. Eight knees (18%) underwent further surgery, three (6.8%) of which were revision procedures, compared to a revision rate of 1.6% in all patients.ConclusionThe outcomes of TKR in patients with early radiological changes of OA are inferior to those with significant radiological changes and should be performed with caution.Level of evidenceLevel IV case-series.