Arthroscopic washout of the knee: A procedure in decline
Introduction
Osteoarthritis (OA) is the most common form of arthritis and one of the leading causes of disability worldwide [1]. It is a chronic condition characterised by pain, stiffness and reduced function. Pathologically, there is involvement of all joint structures but the key features of OA are a reduction in articular cartilage synthesis with an increase in cartilage degradation [2] together with changes in the subchondral bone [3]. There is no single risk factor for the development of OA. It is a complex, multifactorial disease that occurs as a result of genetic predisposition [4], obesity [5], ageing [6] and excessive joint loading [7], [8], [9]. Epidemiologically, there is a strong female preponderance [10] and there is some difference in the prevalence between racial groups depending on the joint in question [11]. Although there are no recent estimates of the prevalence of OA, it may be as high as 8.5 million in the UK population [12]. Initial treatment currently focuses on conservative measures including analgesia with non-steroidal anti-inflammatory drugs (NSAIDs) and local muscle-strengthening exercise [1]. However due to the progressive nature of OA, these initial measures eventually become ineffective for most patients, in terms of pain control, functionality and overall quality of life.
Arthroscopic washout for knee OA is thought to offer short-term symptomatic relief by reducing the inflammatory response mounted against debris, such as articular cartilage fragments and crystals, which accumulate in the synovial cavity [13], [14]. Arthroscopic debridement is similarly thought to offer short-term pain relief as well as short-term increased function by resecting pathological structures such as unstable articular cartilage, proliferative synovium, torn menisci and osteophytes [15].
Based on the available evidence, the National Institute for Health and Care Excellence (NICE) issued the following guidance [16] in 2007: “Referral for arthroscopic lavage and debridement should not be offered as part of treatment for osteoarthritis, unless the person has knee osteoarthritis with a clear history of mechanical locking”. A 2008 Cochrane review [17] of the evidence for knee arthroscopy concluded that there was no benefit, functionally or in terms of pain relief, from arthroscopic washout or debridement for knee OA, when compared to each other or with placebo. In the United States, there has been considerable discrepancy between actual clinical practice and the recommendation of the American Academy of Orthopaedic Surgeons against the use of arthroscopy for the treatment of knee OA [18] as nearly 1 in 5 patients had potentially been inappropriately treated with arthroscopy for knee OA [19]. To date, there has been no evaluation of the number of arthroscopic procedures performed in the UK on patients with knee OA since the 2007 NICE guidance [16] and 2008 Cochrane review [17] on arthroscopy for knee OA. Therefore, in order to assess whether current clinical practice is in accordance with the latest guidance and evidence, we looked at the number of arthroscopic procedures performed since 2000.
Section snippets
Methods
Data on arthroscopic procedures performed in the UK was obtained online from Hospital Episode Statistics (HES). HES is an annual collection of hospital records of all patients admitted to National Health Service (NHS) hospitals, including outpatient appointments [20]. OPSC-4 procedure codes were chosen based on those cited in the latest NICE guidance on arthroscopy for knee OA [16] to identify arthroscopic interventions that were most likely to correspond to debridement and washout (Table 1).
Results
Between 2000 and 2012 there was a decrease in the number of most arthroscopic knee interventions being performed, except for meniscal resection, which increased. The largest decrease was in the number of irrigations performed, which fell by 39.6 per 100,000 population (80%) (Fig. 1). The smallest decrease, 0.94 per 100,000 population (26%), was in the number of loose bodies removed, which remained almost constant from 2000 to 2012, except for a peak in 2008 (Fig. 2). The number of other
Discussion
The number of arthroscopies performed for knee OA appears to be decreasing. The increase in the number of arthroscopic meniscal resections is difficult to explain since it is well established that even partial meniscectomy is a risk factor for the development of OA [23], [24], [25]. The NICE guidance and 2008 Cochrane review on arthroscopy for knee OA appear to have had more impact on debridement rather than washout rates, since washout rates have constantly declined from 2000 whereas the
Conclusion
There has been a steady decline in the number of arthroscopies performed in the UK on patients aged over 60. This may be as a result of NICE guidance and the 2008 Cochrane review which concluded that there was no benefit in performing arthroscopic debridement in undiscriminated OA of the knee. The increase in the number of arthroscopic meniscal resections performed may warrant further evaluation in its own right considering the potential adverse outcomes associated with meniscal resection.
Conflicts of Interest
The authors declare no conflicts of interest.
Acknowledgements
The authors did not receive funding for this study.
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