A Danish study has cast doubts about the long term benefit of knee arthroscopy, saying the surgery is potentially harmful.

The long-term benefits of knee surgery for middle aged or older patients are outweighed by the negative consequences, a study has found.

Around 150,000 middle aged and older adults with persistent knee pain undergo a knee arthroscopy in the UK each year, but researchers said such surgery is potentially harmful.

Although rare, patients can suffer from infections, deep vein thrombosis, cardiovascular problems, pulmonary embolism and even death.

The research, led by the University of Southern Denmark, involved the analysis of 18 different studies and concluded that the "small, inconsequential benefit" only lasted one to two years after surgery.

Patients experienced less pain for the first six months after surgery - but not for any longer, while there was no effect on their ability to physically function at any stage.

"The small inconsequential benefit seen from interventions that include arthroscopy for the degenerative knee is limited in time and absent at one to two years after surgery, the study concluded.

"Knee arthroscopy is associated with harms. Taken together, these findings do not support the practise of arthroscopic surgery for middle aged or older patients with knee pain with or without signs of osteoarthritis."

The study is published in the British Medical Journal as part of its Too Much Medicine campaign, which aims to highlight the waste of resources caused by unnecessary care and the potential harm it can cause.