…but I thought a new knee would fix my pain!

Working in an orthopaedic surgery department is quite enlightening. Along with discussions about ceramic vs metal implants and cartilage regeneration (I work with a team of researchers looking at how to create replacement cartilage), the topic of what counts as a surgical success in knee surgery also comes up from time to time. Knee joint replacement isn’t as successful as hip joint replacement for a number of reasons including the complex nature of the joint, the way the joint capsule is disrupted during surgery, and the knee can apparently feel quite different from the original knee.

What this means is there can be quite a mismatch of expectations for people who believe very strongly that there should be no pain and they should have a completely normal knee joint after surgery. In fact, in the NZ National Joint Registry, the main reason recorded for knee joint revision is pain.

Naturally, the problem of pain after surgery is something surgeons and researchers are also interested in. Many studies have shown psychological factors such as catastrophising (thinking the worst) and low mood are associated with poorer outcomes (Riddle, Wade. Jiranek, & Kong, 2010; Roth, Tripp, Harrison, Sullivan & Carson, 2007; Shelby, Somers, Keefe, Pells, Dixon & Blumenthal, 2008).  The outcomes looked at so far include length of stay in hospital at the time of surgery, analgesia use during surgery, increased disability after surgery and revision rates.

Now, one solution to this problem could be simply not performing joint replacement surgery in people who are depressed and tend to think the worst. The problem is that two of the strongest predictors for looking for treatment are – you guessed it: low mood and catastrophising (and disability). Another solution is to provide intervention after surgery to target the people who tend to become fearful – perhaps an enhanced level of physiotherapy for this group, while the less vulnerable may even require less. Some studies have also looked at giving better education about what the surgery entails and the expected outcomes, and doing this before the person undergoes surgery, while another study has looked at providing a pain coping skills training course prior to surgery (Riddle, Wade, Jiranek & Kong, 2011). The outcomes from this last approach were promising, although it was a very small sample size, and the follow-up was for only two months.

There are a number of problems with implementing any of these approaches in clinical practice, at least in the system I’m most familiar with (NZ):

  1. Many orthopaedic surgeons still discount the importance of psychological factors, and consider the information they provide completely adequate for presurgical preparation
  2. It’s difficult to give someone different or special treatment based on psychological factors within a usual clinical setting without also inadvertently giving people a label that may change how they are responded to
  3. Any additional intervention will have an up-front cost (not good for cost accountants!)
  4. These treatments need specially trained clinicians who understand the measures being used, the rationale for treatment, and the type of treatment needed – and because these are psychological factors and surgery is conducted in a “physical” hospital, this is unfamiliar territory for many
  5. Patients may not be very comfortable with a treatment that focuses on thoughts, emotions and pain

It seems to me, and from the results from a recent study looking at analgesic use after surgery, that an argument simply based on the cost of failing to go ahead with effective management of psychosocial factors would make sense. Here’s the detail:

Fuzier, Serres, Bourrel, Palmaro, Montastruc and Lapeyre-Mestre (2014) conducted a large study of patients in the Midi-Pyrenees region of France. They examined the medical records of all 1939 patients who had knee arthroplasty, and compared the drug use (what was dispensed) at four times – 12 months before surgery, 2 months before surgery, and 10 months before and after the knee surgery.  What they found was an increase in analgesic, antineuropathic and opioid drug use in the 12 months after surgery. The actual percentage of patients requiring more medication is astonishing: 47% of people needed more analgesia, 8.6% needed more antineuropathic medications, and 5.6% needed more opioids. That’s a whole lot of drugs!

These researchers also analysed a number of other variables associated with the medication changes, and made some more understandable findings:

  • people having total knee replacement surgery were at a greater risk of using more medication than those having unicompartmental surgery (half a joint)
  • people with high levels of preoperative pain along with “psychiatric vulnerability” were at greater risk of having increased neuropathic medications prescribed
  • but older people were less likely to be prescribed additional medications

Unfortunately, this study didn’t identify the particular “psychiatric vulnerabilities” of the patients who participated – from the paper it looks like data was extracted from clinical records, so psychiatric disorders such as depression, anxiety and so on are the likely culprits. We don’t therefore know whether catastrophising contributed to the medication use – but given the results from at least 20 studies I have in my database, I think it’s probably likely.

Medications are not cheap. While they’re quick to prescribe, dispense and take, they cost not only in fiscal terms (which is a serious consideration, nevertheless), but also in side effects – and more importantly, in loss of personal locus of control. What I mean by this is that these are people who haven’t been given the opportunity to develop pain self management skills. They will continue to catastrophise, and perhaps even more so after surgery because their fears have been confirmed. Maybe it’s cheaper and more humane to bite the bullet and begin giving people appropriate psychosocial treatment before, during and after surgery.

Fuzier, R., Serres, I., Bourrel, R., Palmaro, A., Montastruc, J., & Lapeyre-Mestre, M. (2014). Analgesic drug consumption increases after knee arthroplasty: A pharmacoepidemiological study investigating postoperative pain PAIN®, 155 (7), 1339-1345 DOI: 10.1016/j.pain.2014.04.010

Riddle, D. L., Keefe, F. J., Nay, W. T., McKee, D., Attarian, D. E., & Jensen, M. P. (2011). Pain coping skills training for patients with elevated pain catastrophizing who are scheduled for knee arthroplasty: a quasi-experimental study. Archives of Physical Medicine & Rehabilitation, 92(6), 859-865.

Riddle, D. L., Wade, J. B., Jiranek, W. A., & Kong, X. (2010). Preoperative pain catastrophizing predicts pain outcome after knee arthroplasty. Clinical Orthopaedics & Related Research, 468(3), 798-806.

Roth, M. L., Tripp, D. A., Harrison, M. H., Sullivan, M., & Carson, P. (2007). Demographic and psychosocial predictors of acute perioperative pain for total knee arthroplasty. Pain Research & Management, 12(3), 185-194.

Shelby, Rebecca A., Somers, Tamara J., Keefe, Francis J., Pells, Jennifer J., Dixon, Kim E., & Blumenthal, James A. (2008). Domain specific self-efficacy mediates the impact of pain catastrophizing on pain and disability in overweight and obese osteoarthritis patients. Journal of Pain, 9(10), 912-919.


  1. The approach by Riddle et al. (2011) is eminently sensible, particularly in that it utilises telephone-based sessions to reduce costs. However, eight sessions of treatment may still be difficult to justify. A shorter, or, at least, variable length, program may be more palatable for fiscal decision-makers.

    1. Thanks for your comment Laith. The question, I guess, is whether a shorter programme would be sufficient – after all, a shorter course of antibiotics is not cost effective! There is some evidence of a dose-response in pain self management, and given the ongoing (life-long) cost of pharmaceuticals (as indicated in the study I quoted today and because people with chronic pain don’t generally recover and neither do they die from their pain) I think it’s one of those questions that financially responsible policy-makers need to weigh up very carefully indeed. Alternatives of course include web-based or app-based approaches, but these appear to have less effect than face-to-face programmes, while group approaches are more cost effective than 1:1 programmes. I don’t think anyone has carried out a full cost analysis of these alternatives. To date it seems the problem is (a) not visible to policy makers or (b) seems to easy to ignore, but I’d argue that with an aging population with a greater number of people with age-related chronic conditions, this will be an increasingly important issue to address.

      1. Completely agree. In a perfect world, these decisions would be made in light of a thorough, rational, long-term analysis. I suppose my point is that, in practice, ‘softer’ considerations in relation to change management are also important. Inertia to an eight-session program might be extremely difficult to overcome; however, a shorter program, or an alternative (cost-minimising) approach, may be more readily accepted by policy-makes (who, sadly, are often judged by relatively short-term outcomes). I’m not saying that we should simply assume that a shorter or different program would also be effective – just that we should make it a priority to explore such questions, since these programs could likely be implemented with less resistance.

      2. Good points Laith, I agree (sadly!). I guess I get frustrated that this information has been available for such a long time but hasn’t gained traction in the places it’s needed most. I hope we can develop a brief intervention that can be delivered easily and inexpensively, but in the meantime people’s lives are disrupted by pain and medications. It’s a long road to walk at times!

  2. It is very pleasant for me, as physiotherapist to see that the problems takes the same direction over different countries.
    I work on a large health care center on Brazil, with a multidisciplinar team of suergeons and therapists specialists on spine disorders. The complaint of the patient is always the pain, but although we discuss the case with the psychiatrist and psychologist, seldom the team looks for the sensorial integration and what should be done with the pain, not only the mechanical problem.

    “The pain will continue, that’s not the problem, but we will save your spine and movements” – that’s the discourse.
    “For that pain, we will prescripte you the right medicament, but is very important to know that this pain can get worse from now on for a time, and you will have to learn to live with that”.

    And when we look the Inicial Complain: Pain on my back/knee/legs, etc.
    The PAIN will remain, and there’s no treatment pre/post surgery. Only farmacos.
    The patient is prescribed to the physical therapy, but the pain was never treated before, explained and tried to diminish the cinesiophobic and catastrophising frame.
    We have contact with a patient that long time ago lost the capacity of understand a good from a bad stimulus, every movement and every task hurts or may worse the structure…It’s very difficult to have a decrease on the medicament use and to liberate the patient’s fear. Especially on a system that distributes pills so easy, as Brazil is.
    I strongly support the PRE-treatment of the phobya and a initial explain of what the pain is and might become after surgical aproaches. Any orthopedical at least.

    1. Thanks so much for taking the time to comment Rafael. It’s sad to know that the problems of postsurgical disappointment and mismatched expectations isn’t managed early, but as Laith points out, this is a system change which takes time. I get frustrated with the pace of change, but I need to remind myself that it takes many bites to eat an elephant!

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