A specialist orthopaedic hospital is reviewing the methodology used for patient reported outcome measures after it was identified as a possible “negative outlier” by the Department of Health.

The DH’s second quarterly report for 2011-12, published just before Christmas, included PROMs data for four conditions: varicose veins, groin hernia, hip replacements and knee replacements.

PROMs are based on questionnaires answered by patients before and after treatment and are intended to measure the clinical quality of treatment from the patient’s perspective.

The provisional figures suggested the proportion of patients reporting improved health after knee replacement and groin hernia treatments had risen over the past three years, while the proportion reporting improvement after varicose vein and hip replacement surgery had fallen.

For the first time provisional lists of the organisations that fared best and worst against the measures were provided.

Among the 10 NHS providers listed as potential “negative outlier organisations” was the Royal National Orthopaedic Hospital Trust. It was the only organisation identified as a potential underperformer against both orthopaedic procedures tracked.

A trust spokeswoman said the trust was a “tertiary” hospital, which receives 80 per cent of its referrals from other secondary care providers.

The spokeswoman added: “For [patients with complex conditions], we provide a unique, tailored treatment pathway which maximises the potential for their recovery. We are reviewing the case mix adjustment methodology used for PROMs and will be making suggestions as to how this can be developed in future.”