Several British patients are considering legal action over the tissue they received from body parts stolen in the United States, solicitors Irwin Mitchell said.
More than 40 British patients are known to have received bone graft tissue - which is used as a filler in orthopaedic surgery such as hip replacements and jaw construction.
There are concerns the material could be contaminated but the Medicines and Healthcare products Regulatory Agency (MHRA) has said the risk was minimal.
Irwin Mitchell said it was acting for a handful of patients but expected the number to rise.
They are considering legal action against a number of the US-based individuals and organisations, it said.
Suzanne Green, 32, from Caerphilly, near Cardiff, was one of the patients treated with suspected stolen body parts.
She was treated for a fractured spine and ankle at the University Hospital of Wales in September last year.
In a statement through Irwin Mitchell, Mrs Green said: "I can't believe what is happening, it's horrific.
"I did not even know I had received a bone graft during my operation until September of this year. I am now in torment wondering whether I have contracted anything from these illegal implants.
"I am awaiting the results of blood tests to see whether I currently have any of the possible infections identified, but I am unsure at the moment what the long-term implications will be."
