Thousands of knee operations carried out each year ‘aren’t justified’

    29 July 2016

    The NHS carries out thousands of unnecessary knee operations every year, according to a study in the British Medical Journal.

    Over 150,000 operations on the meniscus — cartilage between the knee joints which is easily damaged by twisting — are performed on the NHS annually.

    Surgery involves inserting a tiny camera inside the knee while the procedure is carried out through small incisions in the skin. It takes less than an hour and usually the patient doesn’t have to stay in hospital overnight. But the new study suggests that the treatment is no more effective than doing exercises.

    During the study, progress was monitored in one group of patients who had the surgery, and another who carried out a 12-week exercise programme. No ‘clinically relevant difference’ was found between the two groups.

    The researchers say that, in the short term, exercise therapy showed positive effects over surgery in improving thigh muscle strength.

    Teppo Jarvinen, writing in a separate editorial in the BMJ, said: ‘What we should not do is allow the orthopaedic community to ignore the results of rigorous trials and continue widespread use of procedures for which there has never been compelling evidence.’

    Instant analysis
    This was a small, randomised controlled trial at two orthopaedic departments, with the aim of comparing two interventions within a specific grouping of patients: middle-aged patients who had degenerative medial meniscal tears identified by MRI, who previously had almost no evidence of osteoarthritis on X-ray imaging.

    The study was informed by the fact that, although there was a small benefit in having knee arthroscopy in some cases, this was eventually negated within the first year, at great cost and with a potential risk of complications.

    Furthermore, the rate of surgical intervention and arthroscopy for this type of knee damage has soared in the last few decades. Evidence exists to suggest that exercise improves function and activity level in these patients.

    The trial subjects were compared according to intervention (12 weeks of progressive neuromuscular and strength exercises at two to three sessions a week versus surgery) and followed up over three months, one year and then two years. The study intends to follow up on radiological change over five years, so data is still pending.

    The endpoints on the study were muscle strength at three months and knee function after two years. The patient-reported endpoint was changed from their baseline function to two years, gauged in an outcome score.

    Out of 140 randomised patients, in the exercise group 43 out of 70 performed well. However, in the surgical group, six did not undergo surgery.

    In summary, the surgical group reported a better outcome score after one year, but after two years the groups were roughly at the same level. However, the exercise group preserved and retained function as a result of not requiring recuperation and also by improving strength.

    Due to the sample size, and spread of data, it was difficult to favour one intervention over the other, apart from patient-reported symptoms, which favoured exercise intervention.

    The limitations of the study were a small group size and a significant drop-out and compliance rate in the exercise group. The team note that a ‘sham’ surgery group would help to diminish any placebo effect in the surgical intervention group.

    In summary, the study offers a conclusion shared by many: that often surgical intervention is not the answer, especially for marginal pathology. The introduction of an effective strength and functional exercise regime might buy more time while improving symptoms, and it still allows for the option of arthroscopy at a later point. This mitigates both cost and risk, and perhaps may influence policy in resource-finite circumstances.
    Research score: 2/5