Who Needs a Knee Replacement?
Somewhere between 10 and 12% of Ontarians have a diagnosis of osteoarthritis (OA) in one or more joints. Of that number, many will be impacted in one or both knees. Of that number, a percentage will go on to receive a Total Knee Arthroplasty (TKA), also known as a knee replacement. Between 2014 and 2015, slightly more than 61000 TKAs were performed in Canada, representing a 20% increase over the previous 5 year period.1
Many of you, especially if you are over age 55, likely know someone who has had a knee replacement in their lifetime. For many in this group, a joint replacement is the only solution to debilitating knee pain and is often freeing from a dependence on opiates.
But….Some people do not have good outcomes…
An emerging field of rehabilitative and orthopaedic research is attempting to identify, prior to surgery:
Who in the group is most likely to experience a poor outcome and direct them to alternate treatments, such as physical therapy.
Traditionally, poor outcomes have been orthopaedic-centric in their definition. This is usually based on the number of people needing a second replacement (a revision).
Usually this number is less than 2%.
Many more people than this, however, report continued pain, decreased function, or reduced physical activity after the replacement. This is a more holistic approach to the question.
A colleague of mine who works in a joint replacement clinic here in Ontario forwarded be an article the other day which intrigued me. Published in 2016, the English researchers retrospectively looked at those patients who reported a negative outcome (negative being subjectively judged by the patient) and attempted to identify which characteristics they had in common with each other. This is not the ideal way to establish prognosis, but it is the next best thing. This sample exclusively examined individuals under the age of 55, as previous research has established that outcomes are worse in this group relative to older people.
Out of this group, 25% reported a poor outcome – which seems crazy to me.
Statistically significant variables correlated with poor outcomes included worse pre-surgery status and lower grade of arthritis on imaging. Both of these should be expected, even by the non-clinician.
Interestingly, other traits included:
- History of prior knee surgery (such as scopes or ACL repairs)
- Arthritis secondary to trauma
- The presence of inflammatory arthritis.2
This is just one paper with one set of characteristics and one unique group of individuals, not to mention one group of surgeons. It would be unreasonable to generalize these results back to our side of the pond. The point is that a knee replacement is not the perfect solution for all instances of chronic knee pain. While appropriate for many, there are some individuals who would benefit from an alternate course of treatment. It is important to have these discussions, especially for those of you under 55, with your Physiotherapist, Family Doctor, Orthopaedic Surgeon or other medical authority you trust, before making the decision to go under the knife. No surgery is routine, and the decision to undergo one should be made with best available evidence.
- Canadian Institute for Health Information. Hip and Knee Replacements in Canada, 2014–2015: Canadian Joint Replacement Registry Annual Report. Ottawa, ON: CIHI; 2017
- Scott CEH et al. Predicting dissatisfaction following total knee arthroplasty in patients under 55 years of age. Bone Joint J. 2016(98):1625-34