Surgeons are no better at determining which patients might benefit from an operation or exercise to treat torn knee cartilage than if they just flipped a coin, a study suggests.

Dutch researchers surveyed 194 orthopaedic surgeons to see how they thought patients would respond to either arthroscopic partial meniscectomy or exercise therapy in a survey using 20 test cases with middle-aged patients with non-obstructive meniscal tears.

They also asked the surgeons which of the two treatments they would recommend in each case.

The test cases were based on the five best and five worst responders in each arm of the ESCAPE randomised controlled trial, which allocated patients aged 45-70 to either exercise therapy or arthroscopic partial menisectomy.