The United States subsidiary of the Swiss company, Sulzer Medica, one of the world's leading medical-device makers, has denied responsibility for injuries relating to faulty hip replacement implants.
The Texas-based implant manufacturer, where the defect was initially detected, Sulzer Orthopedics, had earlier accepted sole responsibility for the faulty parts.
However, lawyers for the subsidiary are now contending, in initial answers to several lawsuits, that patients and unidentified third parties are at fault for the hip implant failures.
The discovery of the defect led to a massive recall last December. Sulzer Medica is faced with lawsuits in the US for allegedly failing to warn thousands of patients about the dangers of the hip replacement implant.
So far, about 650 patients have had surgery to replace the faulty parts -- a major operation that generally requires up to three months of recovery.
Hundreds of patients are suing Sulzer for their suffering, lost wages and other hardships, while lawyers in some national court cases are seeking class-action status.
Sulzer Medica announced the voluntary recall of the implant after it found trace amounts of oil had not been cleaned from the implants during the manufacturing process at the company's Austin plant.
In total, 17,500 of the recalled Inter-Op acetabular hip shells were implanted into patients. Sulzer initially estimated that a small percentage would cause problems, but some physicians are now warning that up to half of the patients, who received the implant, may need new surgery.
Swiss-based Sulzer Medica and its Texas subsidiary initially promised to pay for additional surgery resulting from the defective implants.
However, Sulzer Orthopedics' answer to a lawsuit filed by a Texas man, Verlee Fort, was a general denial - a standard Texas court practice that puts the burden of proof of any alleged wrongdoing on the plaintiff.
In a dozen affirmative defences, attorneys for Sulzer also contend the injuries were not caused by the company's acts but by third parties over whom it had no control or authority.
Fort maintains that the hip implant he received in March 2000 had to be replaced because it was defective.
A Sulzer spokesman said these types of legal arguments aren't unusual. "You list anything and everything because you don't know what the other side has," said M.J. Nicchio.
swissinfo with agencies