BOA/BASK response on knee replacement surgery

01 Feb 2012

Recent comments made by the Secretary of State for Health in the Sunday Times regarding knee replacement surgery are inaccurate and both the President of the BOA and the President of BASK have responded firmly to this effect. The following letter was sent to Andrew Lansley on 1 February 2012:


The Right Honourable Andrew Lansley CBE MP
Secretary of State for Health
Department of Health
Richmond House
79 Whitehall
London SW1A 2NS

1 February 2012

Dear Mr Lansley,

Your interview reported in the Sunday Times on 29 January 2012, in which you commented on the outcome of knee surgery, is inaccurate.

You were reported to have made the following statement:

“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.”

To protect the patients around the country who may be alarmed and despondent in case these statements actually reflect the reality of their prognosis, the BOA and BASK would like to draw your attention to the following observations:

  • There has been no study on outcomes of all knee surgery, and therefore no basis to suggest that half of patients having knee surgery derive little benefit.
  • Such a suggestion will alarm patients without justification.
  • Patients waiting for ligament repair or reconstruction, repair of fractures, treatment of torn cartilages and a large variety of other conditions will be given the wrong information about their treatment.
  • We know of no authoritative data which could be used to support the suggestion made by you on any of these many types of knee operations.

It is likely that you were referring to recent Knee Joint Replacement data which have been produced by the January 2012 Patient Reported Outcomes Measures Report from the NHS Information Centre, and an October 2011 Patient Outcomes in Surgery (POIS) Audit report from the Royal College of Surgeons of England that compared outcomes of four common procedures, including knee replacements, in the independent treatment sector and the NHS.

  • The figures from the PROMs data show that 82.2% of patients get good or excellent results when asked how they assess the overall result of their knee operation.
  • There is a second set of figures in PROMs based on EQ5D scores, which are an assessment of the general health and well-being of the patient. This is a general health score which will underestimate the result of the procedure on the knee.

Rate of revision

In many published series the number of patients who have to have another operation to re-do their knee replacement within 10 years of their first operation is around 5%. In other words 19 out of 20 cases do NOT have to have it re-done within 10 years. This is a lasting and successful procedure.

The latest annual report of the National Joint Registry in England and Wales shows that across the whole NHS the revision rate for standard primary Knee replacement is below 4%. So over 96% of knees replaced have no need for revision surgery. Other registries, such as the Australian register, have confirmed this rate. So national and international data confirm that knee replacements last.

Contrary to what you stated, Pain improves markedly after knee replacement surgery:

  • Pain relief in most of the major published long-term studies of knee replacement in the medical literature show that 80-85% of patients report little or no residual pain at rest and only slightly worse figures with day to day activity, with marked improvement from what the patient suffered before surgery.
  • The pain relief data from the government’s own PROMs work show that 38% of patients have severe pain problems prior to surgery and this number is reduced to 6% by 6 months after operation.
  • In contrast only 1% claimed no pain problems prior to operation and this improved to 32% with NO pain problems after 6 months. The majority had some mild discomfort.
  • The results of knee replacement continue to improve for 18-24 months after the operation and therefore these six month data, while reassuring, are still too early to demonstrate the full benefit of the surgery.
  • We expect that follow up PROMs data at 1 and 2 years will show improvements in the rate without pain.

With regard to general well-being the PROMs data show that by 6 months after surgery nearly 70% of patients were MUCH better than before their operation and only 3.4 % felt they were much worse. Again one must remember that these are EARLY data since further improvement occurs in the following year.

You also stated that Mobility does not improve. Your PROMs data shows otherwise. With regard to Mobility problems, the PROMs data state that before knee replacement only 6% of patients complained of NO mobility problems. After 6 months nearly 47% of patients already had no mobility problems, clearly a very substantial improvement which would show considerable further improvement by 2 years if the scores were to be repeated then.

Scoring systems

The Oxford Knee Score is knee condition-specific and is therefore a much more accurate assessment than the EQ5D, which reflects the overall or general health of the patient. 91.6% of cases show an improvement in their Oxford Knee Score at 6 months. The average improvement of over 14 points by 6 months for knee replacement would not be approached by most other operations.

Even Health Economists, who take into consideration the Cost as well as the Effectiveness of the procedure, agree that Hip and Knee replacements give better health improvement for the cost than almost any other form of health intervention for any illness or disease (Laupakis et al).

A knee operation gives lasting benefit and the cost and time is justified. It costs less than £10 per week to get marked and sustained improvement in pain and crippling disability if a knee replacement lasts for 10 years. We are not aware of any other current interventions for painful, arthritic knees that can match the benefit given or the cost of obtaining that benefit.

The BOA has said that data is used by the Department of Health (DH) like “a drunken man using a lamppost, more for support than illumination” (Peter Kay, BOA President 2011). The BOA has clearly pointed out the flaws in how data is being interpreted by parts of the DH. When the entire body of evidence is considered, including data generated by the DH itself (the National Joint Registry 2011 report, Patient Reported Outcome Measures and summarised in Map 53 in the 2nd NHS Atlas of Variation published by the QIPP Right Care work stream) it is clear that almost all patients having a knee replacement are very much better off, with less pain and disability, and that there is little variation in this benefit in the different regions and Trusts in England. This intervention has better information than for any other part of the suggested pathway to manage patients with an arthritic knee.

We are very concerned about the inaccurate representation about the outcome of all of knee surgery, which may clearly have been due to inaccurate briefing or unintentional misinterpretation. However statements like this are not responsible ones as they will raise uncertainty and concern in patients who may then choose not to have surgery likely to ease their pain and disability.

Like Politics, surgery is about improving people’s lives. We have a duty to ensure that our patients are well informed so they can make sound treatment choices. Such misinformation harms patients rather than helping them.

Yours sincerely,

Professor Joe Dias, President            Mr Tim Wilton, President
British Orthopaedic Association        British Association of Knee Surgery


Policy position statements