As you read on, you will discover the two most common methods used in the surgical management of knee osteoarthritis, as well as the studies reported.
Written by Anthony Teoli, MSc, PT
Osteoarthritis (OA) is a degenerative joint disorder that affects more than 10% of Canadians and approximately 250 million people worldwide. OA is a leading cause of pain and physical disability among older adults, with substantial and increasing individual and socioeconomic burden. The joints most commonly affected by OA are the knee, hip and hands, with knee OA accounting for approximately 85% of the burden of OA worldwide.
Best practice guidelines for the management of knee OA consistently recommend that :
Surgical Management for Knee Osteoarthritis
For the purpose of this blog article, only knee arthroscopy (more specifically, arthroscopic partial meniscectomy) and total knee arthroplasty (TKA) procedures will be discussed. These surgical procedures are most commonly performed for the surgical management of knee OA.
Knee arthroscopy is the most common orthopaedic procedure performed, with approximately 700,000 arthroscopic partial meniscectomies performed annually in the US alone. Annual direct medical costs are estimated at $4 billion.
However, recent evidence has put into question the use of knee arthroscopy procedures, specifically arthroscopic partial meniscectomy, for the treatment of patients with degenerative knee disease (i.e. OA). Firstly, arthroscopic partial meniscectomy was not shown to be superior to sham surgery, with regard to outcomes at 1-year and 2-years post-operatively. Furthermore, arthroscopic partial meniscectomy combined with physiotherapy provided no better relief of symptoms when compared to physiotherapy alone in patients with a meniscal tear & knee OA. Similar results were found in a recent systematic review of studies comparing knee arthroscopy to conservative management in patients with degenerative knee disease. Lastly, patients with a history of arthroscopic partial meniscectomy are 10 times more likely to undergo a knee arthroplasty when compared to the general population, 40 times more likely to undergo a knee arthroplasty at a younger age (30-39 years old) when compared to the general population, and 3 times more likely to undergo a knee arthroplasty of the operated knee when compared to the contralateral unoperated knee.
These findings would suggest that any benefit seen from knee arthroscopy in the knee OA population is inconsequential and short-lived, and is associated with potential harms. As a result, as of 2017, there is a strong recommendation against the use of arthroscopy in nearly all patients with degenerative knee disease. This recommendation applies to patients with or without imaging evidence of OA, mechanical symptoms or sudden symptom onset. Further research is likely to alter this recommendation.
TOTAL KNEE ARTHROPLASTY
The end stage treatment for knee OA is total knee arthroplasty (TKA) and consists of replacing the articular surfaces of the tibiofemoral joint (with or without the articulating surface of the patella). TKAs have become one of the most commonly performed surgical procedures worldwide, with over 67000 TKA procedures being performed annually in Canada. TKA rates are expected to increase exponentially in the future.
Total Knee Arthroplasty Procedure
For those interested, here is a detailed animation of the TKA procedure: https://www.youtube.com/watch?v=lLtEdSwqZh4
Although not discussed in this blog article, here is an animation of the unicompartmental knee arthroplasty surgical procedure as well: https://www.youtube.com/watch?v=ZylGnLbrHbw
When is a Total Knee Arthroplasty Indicated?
There is no one criterion that is used to decide whether someone is a candidate for a TKA. There are many factors that must be considered, including but not limited to:
How Long Does a Total Knee Arthroplasty Last?
Results of a recent systematic review and meta-analysis of 33 studies (6490 total knee replacements and 742 unilateral knee replacements) would suggest that approximately 82% of total knee replacements last 25 years and 70% of unilateral knee replacements last 25 years.
What Proportion of Patients Report Persistent Pain Following a TKA?
While most patients experience pain relief and functional recovery after TKA, results from a systematic review of eleven prospective studies (12800 pooled participants) would suggest that approximately 20% of patients continue to report long-term pain following TKA. Chronic post-surgical pain following TKA can cause patients considerable distress and has a significant socioeconomic cost.
Pre-operative factors that have been identified as significant predictors of persistent pain after TKA include: a greater number of pain sites, higher levels of pre-operative pain, higher levels of pain catastrophizing, higher levels of depression and anxiety, and poorer levels of pre-operative function. Having had other pain sites prior to surgery, as well as pain catastrophizing, were identified as the strongest independent predictors of chronic, post-operative pain post TKA. This could be explained by the increased attention and awareness of pain exhibited in patients demonstrating pain catastrophizing, consequently magnifying pain intensity. Moreover, increased joint pain and/or having numerous pain sites prior to surgery could indicate a more sensitized nociceptive system. As a result, a more focused pain management and graded activity approach may be necessary for these individuals to lower pre-surgical pain levels and attenuate central sensitization, potentially improving post-operative outcomes.
Arthroscopic partial meniscectomy is no longer recommended in nearly all patients with degenerative knee disease. In addition, approximately 20% of patients report persistent pain following TKA. It is crucial that patients are communicated this information and educated regarding the potential harms and benefits of certain surgical procedures for knee OA so that they may make informed decisions regarding their treatment plan. It is equally important that patients are made aware that there are other effective treatment strategies, such as exercise, which are safer and provide a multitude of additional health benefits. Lastly, certain pain-related and psychological factors have been identifed to be significant predictors of persistent pain following TKA. Addressing these factors pre-operatively may be an important step in optimizing outcomes post TKA.
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