Successfully alleviating pain in patients with knee osteoarthritis (OA) or in patients with persisting pain after a total knee replacement (TKR) remains a huge challenge. This phenomenon might be attributed to the heterogeneity of the disease.
It has been proposed that OA is a syndrome comprised of multiple distinct phenotypes rather than a single disease (Karsdal et al. 2016). A phenotype in knee OA can be defined as a collection of observable traits (i.e. aetiologic factors, risk factors) that can identify and characterize a subgroup in a defined population.Deveza and colleagues (2017)stated that identifying OA phenotypes would allow targeted treatment for specific subgroups and ultimately the identification of more efficacious treatments.
Dell’Issola and colleagues (2016)reviewed the identification of clinical phenotypes in knee OA. In total, they described the existence of six phenotypes:
As mentioned above, this heterogeneous patient population requires individualized treatment instead of a one-size-fits-all treatment approach:
The aforementioned phenotypes and their specific treatment approaches are mainly useful in the conservative management of knee OA. But what if conservative treatment fails?
TKR surgery is the most common surgical treatment for knee OA. Even though it is an effective surgical treatment for end-stage knee OA and the majority of patients with knee OA report significant pain relief and functional improvement, up to 30% of patients undergoing a TKR are dissatisfied with the postsurgical outcome (Williams et al. 2013). Better insight into factors that can predict poor outcome after surgery may be helpful in screening whether preceding/additional therapeutic modalities are required in order to increase success after surgery.
It seems that we are on the right track with identifying knee OA phenotypes in order to individualize our conservative treatment approach. Let us now go further and examine the predictive value of these phenotypes for TKR outcome, to prevent chronic postsurgical pain from occurring!
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PhD researcher at Antwerp University, Antwerp, Belgium
2018 Pain in Motion
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