A lot of people with osteoarthritis of the knee joint undergo an operative procedure called arthroscopy, with or without scraping away of rough and loose tissue in the joint cavity (called debridement). Now the usefulness of this procedure has been called into question.
Osteoarthritis of the knee is a very painful condition, and medications are not always successful in providing relief. Many patients are tempted to consider a surgical intervention - arthroscopy - as a possible source of help. The procedure involves inserting a small tube with a telescope-like attachment into the knee joint, and washing out the joint space with a fairly large amount of saline (salt) solution. This wash-out is called 'lavage'. Some orthopedic surgeons recommend an additional step, called 'debridement'; this involves removal of any tissues that are dead or obviously in the way, interfering with smooth joint movement, such as pieces of a torn meniscus, a 'loose body' of tissue, fat pads, and so on. Both lavage alone and debridement have been reported (in uncontrolled studies) to be helpful in relieving pain in about half the cases. However, there isn't an obvious explanation as to why they should help control the disease process, so a group of surgeons in Houston, Texas, decided to conduct a placebo-controlled study to see if they actually worked.
What was done
The volunteer patients recruited were under 75 with osteoarthritis of the knee and a moderate degree of pain despite medications taken for 6 months or more. Out of 324 suitable patients, 144 refused to participate when they learned of their chances of receiving 'placebo', or dummy, surgery.
The patients who enrolled were randomly assigned have arthroscopic lavage, arthroscopic debridement with lavage, or the dummy, or placebo procedure; those having arthroscopy had general anesthesia, while those in the placebo group were given a tranquillizer by i.v. and a strong pain-killer. The placebo patients had three small skin incisions made, as if they had had arthroscopy, and their postoperative care was the same as for the arthroscopy groups.
All the patients were evaluated at 2 weeks, 6 weeks, and 3, 6, 12, 18 and 24 months. At each visit, they completed three different assessments of their pain level, and two measures of their knee function were made. The surgeon also measured the time they took to walk 100 ft (30 m) and to climb up and down a flight of stairs.
What was found
A total of 180 patients were enrolled; their average age was 52, and they were almost all men (92%). Half of them had moderately severe osteoarthritis, while 25% had mild and 25% severe forms of the disease. One in 5 of them were on prescription medications for pain.
There were no differences in any of the evaluations made at follow-up visits between the three groups of patients. And the debridement group did worse on the time-to-walk-and-climb-stairs than the other two groups, both at 2 weeks and 2 years.
These results show that the two arthroscopy procedures (lavage and lavage-with-debridement) didn't help the patients with regard to pain relief, their own assessment of disability, and a measure of their disability.
In the USA over 650,000 arthroscopy procedures like this are done each year, at a cost of about $5,000 each. There is clearly a lot of money to be saved in abandoning this apparently useless procedure.
A controlled trial of arthroscopic surgery for osteoarthritis of the knee. JB. Moseley, K. O'Malley, NJ. Petersen, et al., N Engl J Med, 2002, vol. 347, pp. 81--88