Many of the knees could be working perfectly well and would not need to be touched at all

Carmarthenshire NHS Trust spokeswoman

They have been asked to attend an assessment with one of the Trust's orthopaedic consultants.

A Trust spokeswoman said today that in a worst case scenario defects in the implants could be so severe as to warrant a repeat operation.

She said: "What we are very keen to do is avoid any undue anxiety because a lot of the patients affected are elderly.

"Many of the knees could be working perfectly well and would not need to be touched at all."

State-of-the-art

Trust chief executive, Mike Jones, said: "The implant was considered to be state of the art when it was introduced, but it has been found to have a higher-than-usual rate of early loosening.

"The manufacturers have contacted previous users of the knee, including Carmarthenshire NHS Trust, to alert them to this fact and advise them on potential solutions.

"We have now identified all the patients who received this knee and in a letter to them they have been invited to be assessed by one of our consultant orthopaedic surgeons."

Mr Jones said only that stage would it become clear whether any further treatment was required.

"As we pointed out in the letter, it my be that the patient's knee is functioning well.

"The Trust is very keen the patients involved should not be unduly worried and we have, therefore, prepared an information sheet to make details available to them.

"Patients can also contact our consumer liaison nurse who will help answer any queries they or their families may have."