Parachute trial: on the subject of knee arthroplasties

The concept "parachute trial" has been adopted to visualize that when a treatment is really effective perhaps one should not invest money in demonstrating what everyone knows, just as no one would think to make an essay on the effectiveness of the parachute. The New England Journal of Medicine has published a clinical trial (Skou 2015) that evaluates the clinical effectiveness of knee arthroplasty, and the journalist of the magazine asks: Did it have to be done? Arthroscopic knee replacements are one of the most significant advances in modern medicine. Everyone knows that many older people who could not leave the house, invalidated by pain, now not only go out every day to the market square but they often go cruising. Seen like this, is this not a "parachute trial"? A waste?

The Skou clinical trial started from a group of 100 patients with symptomatic knee osteoarthritis, half of whom underwent total joint replacement with subsequent rehabilitation for one year, while the other half followed non-surgical treatment also of twelve months, based on physiotherapy, diet, insoles and analgesics. As expected, the results were clearly favourable to surgery, but the surprise of the job, at least for me, was that in the medical therapy group, 68% of patients reduced pain, compared to 85% of the surgical group. On the other hand, of course, there were complications in the surgical group: three deep vein thrombosis, one wound infection, one supracondylar fracture and three episodes of joint stiffness requiring manipulation with anaesthesia.

For most people with disabling joint pain, surgery is clearly the choice but so it was for many of the patients in the nonsurgical group of the trial, once the supervision period of twelve months had passed. But apart from the complications mentioned, it’s necessary to know that arthroplasty is not universally successful. In this study we have seen that pain doesn’t disappear in 15% of cases, but other studies indicate that there are 20% of people who continue to be in pain six months after the intervention.

Arthroplasty is a preferred choice for crippling osteoarthritis of the knees (but not a parachute), and family physicians and traumatologists should be able to explain the pros and cons of therapeutic options, and more importantly, they should know how to listen to patients, because when it comes to pain, each person is in their own world.

Jordi Varela

Editor