Chapter 1: Introduction and background
1.4 Problems facing knee replacement services
Although knee replacements are effective both in terms of cost and outcome, there are three problems facing the provision of knee replacements. First and foremost, there is a variation in the outcome – around 17% of patients are dissatisfied with the outcome of their operation, although estimates vary.22,23 Secondly, and by no means specific to knee replacements, there is increasing demands coupled with financial constraints. Thirdly, there is a variation in the utilisation of knee replacements.
1.4.1 Variation in outcome
Questions have been raised about the benefits of knee replacements, and some studies report up to 17% of patients are dissatisfied with the outcome of knee replacement surgery.17,22,24 The situation (regarding knee surgery in general) has been commented on by the Secretary of State for Health, who was reported to say in 2012:
“An interesting case in point is knee surgery; the data has now come back
demonstrating half of knee surgery doesn’t substantially change the outcome for patients: their mobility isn’t improved that much, nor their pain.”25This comment was met with disappointment in the orthopaedic community, not least from the British Orthopaedic Association (BOA) and the British Association for Surgery of the Knee (BASK). They cited the words of a former BOA president that the
Department of Health (DoH) uses data like “a drunken man using a lamppost, more for support than illumination”.25 Although these comments were widely regarded as
unnoticed. Patients that are dissatisfied tend (unsurprisingly) to have worse Patient Reported Outcome Measures (PROMs) scores, such that they display worse pain outcomes and worse functional outcomes that those that are satisfied.26
A research prioritisation workshop on hip and knee replacement, sponsored by Arthritis Research U.K., the NJR, and the BOA, identified the question of '... which patients had poor outcomes and were dissatisfied...' as the most important research question in knee surgery today.25 Additionally, the James Lynd alliance priority setting partnership, conducted in collaboration with the National Institute for Health Research (NIHR), has the identification of pre-operative predictors of success as one of its “Top Ten” research questions; and the National Institute for Health and Care Excellence (NICE) has stated that the development of methods to predict outcome in knee replacement is a research priority.12
1.4.2 Increasing demand with financial constraints
Currently the U.K. government has ring-fenced the NHS budget against the austerity measures imposed after the global financial crisis of 2008.27 However, a King’s Fund report into NHS performance revealed a £630 million deficit half way through financial year 2014/15.27 They predict an additional £8 billion in funding will be needed each year by 2020. The present Conservative government has committed to meet this shortfall; however, the financial calculations are based on a £22 billion efficiency saving
In any event, efficiency savings appear to be a key strategy to managing the ever- growing budget.28 A more judicious use of knee replacement surgery, combined with the best possible conservative care, has potential to decrease the number of knee replacements performed (or slow the increasing numbers needed), and may go some way to relieving the financial pressure.
1.4.3 Variation in the utilisation of knee replacements
Variation in the utilisation of healthcare has been present within the National Health Service (NHS) for decades, and was the explicit reason for the establishment of NICE in 1998 (a move against the “postcode lottery”).29 Although hailed as a success at
addressing healthcare inequalities, NICE has a limited role in guiding decisions over total knee replacement. NICE guidelines on the treatment of knee OA are available;2 however, as knee replacement is a preference-based decision, no formal criteria have been agreed.16 Indeed, the pathway from patients attending GPs, referral to
orthopaedic services, and receipt of a joint replacement is inconsistent.30
The NHS Atlas of Variation describes knee replacement utilisation in different areas of the country.31 Differences in expenditure of almost fourfold are demonstrated between Primary Care Trusts (PCTs) with regard to inpatient knee replacement costs; however, those Trusts with the highest expenditure reveal patients with the best pre-operative PROM scores. In other words those areas where there is objectively the lowest need (as measured by pre-operative PROMS) there is the highest rates of knee replacement – the so-called “Inverse Care Law”. Some authors dispute the validity of assessing
individual need based on PROMs;25 however, the case remains that there appears a population level discrepancy in knee replacement utilisation.
In a recent systematic review, this variation in the utilisation of total knee replacement has been described by age, gender, race, education, income/health insurance (only studied in the USA), and employment.32 Within the UK, the British Medical Journal (BMJ) reported that rates of knee replacement vary by age, gender, deprivation, rurality, and ethnicity. 33
Warranted versus unwarranted variation
The NHS Atlas of Variation defines warranted variation as that explained by patient need or patient preference, and unwarranted variation as due to differences in access to healthcare and clinical practice.31 Simplistically, this could be divided into demand (patient preference) and supply (access).
Recent studies have demonstrated that there is a marked warranted variation in knee replacement surgery. Only around one third of patients considered to be at need of a joint replacement would be willing to undergo a joint replacement.34 Therefore patients’ willingness to undergo a knee procedure will affect demand (and therefore affect geographical variations in utilisation).
Several studies have demonstrated that willingness to undergo a knee replacement varies by age, race, how OA is viewed (a natural process involved in getting older compared to a disease), and the amount of pain and disability that is required to justify the operation.32,34 Furthermore, expectations of the outcome of the operation varies by
operations, and that in turn may affect utilisation of knee replacements in a given population.
Within the U.K. it is clear that not all the variation is warranted (i.e. due to patient need or preference). For example, orthopaedic surgeons and general practitioners have been reported to be less likely to refer a woman with OA of the knee for knee replacement than a man (although more women actually have the procedure).39
Overall the factors that influence the variation in uptake of knee replacement surgery is likely to be a mixed picture of patient need, patient preference, access to healthcare, and clinical practice. Understanding how patients make decisions about having a total knee replacement could explain some of this variation.