Knee Replacement
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Knee replacement at your local hospital

In Part I we looked at how to answer the question: How good is your local hospital? And in Part II we saw that the results for the Duchy Hospital are among the best in the country. So, are there any problems with this data and what about knee replacement; can the Duchy knee surgeons keep up with the hip surgeons?

As a quick refresher, Patient Reported Outcome Measures (or PROMs) measure what matters to patients. And it’s the Oxford hip and knee score that effectively measure pain and function before and after hip and knee replacement. Twelve questions, each scored from 0 to 4, give a total out of 48 points; so 0 is bad and 48 is good pain and function. We know that the Duchy results for hip replacement are good, but what if you or a loved one is considering knee replacement? Is the pain going to be less, or is there a chance you could be worse off, and what about function?

Well, take a look at the results for knee replacement in Figure 2 (see below).


 Figure 2: Oxford knee scores for Duchy Hospital

There were 173 knee replacement patients last year, 2015-16, scoring an average health gain of over 18 points. The UK average gain was around 16 points. Again, significantly better than the average hospital, and another important difference in what really matters to patients. As with hip replacement, the Duchy Hospital is again described as an ‘Outlier’ and ‘Positive (95%)’. As described in Part II, this statistical measurement puts the Duchy in the top 2.5% of hospitals nationwide. And was this a one off? Well, no. Note the year before, in 2014-15, the Duchy was a positive 99.8% outlier. This statistic places the Duchy result among the top 0.1% of UK hospitals performing knee replacement.

So are there any problems with this data and how it’s used? Well, any data must be looked at with some caution and there are a few problems with National PROMs Programme to take into account:

  1. Missing information: a significant proportion of patient data in the National PROMs Programme is not collected. It’s not always clear, as these articles have hopefully shown, how useful this data can be; so some patients don’t return the questionnaires;
  2. Pen and paper: the Oxford question sets are collected on paper, collected together by a company, passed to the NHS Information Centre and reported online and to hospitals. The system, in its current form, is complicated and expensive; web based systems are, however, starting to streamline the process and make it easier for everyone;
  3. Patient mix: patients attending different hospitals have different medical problems and levels of function to begin with some, but not all; of this variation taken into account;
  4. Two time points only: the National PROMs Programme only collects Oxford scores at two time points, before the operation and six months afterwards. Patients want to know what their pain and function will be like at one year, 5 years or even 20 years after joint replacement; and we currently don’t collect information beyond six months.
  5. Delay between data collection and reporting: clinicians and, more importantly, patients can’t see the data immediately, in so-called real-time, and so can’t use the information when it’s most useful. A weather report published six months late isn’t much use; same with these reports.

Technology, the internet and innovation will improve the data over time, but even as The National PROMs Programme shows patients far better information than has been available previously and points us in the right direction of measuring what really matters to patients. And some surgeons are going further; making their key results are available online. See, for example, this surgeon’s patient website showing not only Oxford hip and knee scores at six months but what recovery looks like out to 12 months, 2 years, and 5 years. 

So from now on, instead of choosing a hospital by “I heard John Smith’s knee replacement went well”, we can start to say that “my hospital has some of the best pain and function results in the country”.

Dan H Williams FRCS

Consultant Orthopaedic Surgeon