The increasing demand for knee replacements: a hostage to fortune

Abstract

Osteoarthritis (OA) of the knee is a huge problem. Even in our small group practice we have hundreds of patients who suffer daily pain and disability. Knee replacement surgery is a very effective remedy, but can be risky, and quite a lot of patients are medically unfit for the procedure. Analgesics, systemic and topical non-steroidal anti-inflammatory drugs, and intra-articular (IA) steroid injections provide limited or short-term benefits and physiotherapy and other conservative approaches may improve mobility but have less impact on pain. Things are going to get worse in the future. Knee pain and disability are very strongly related to obesity, which, as we know, is rising fast. We are putting in knee replacements much more frequently than even 5 years ago. According to the National Joint Registry there were over 80 000 primary procedures in 2011; up from around 60 000 5 years before, and increasing by around 3% annually. Around 17% of procedures are done in patients aged <60 years, and the average age is 67 years. The majority of patients are obese and this proportion is growing. In 2013, 21% of patients had a BMI of ≥35, whereas in 2006 it was 15%.1 Younger, and therefore more active patients, are at greater risk of implant failure, as are obese patients. There are around 5000 (6%) revisions out of 88 000 total procedures in England each year. However the need for revisions is bound to increase considerably with the increase in primary procedures and the tendency to operate on younger and more obese patients. In the US in 2010 there were 55 000 revisions (8%) compared with 658 000 primary procedures.2 Nearly half of the revisions were in patients <65 years, emphasising the …