Metal-on- Metal Hip Implants associated with High Incidence of Pseudotumors.
Another study has shown the potential danger associated with metal-on-metal hip implants. The newest study, published in the journal of bone and joint surgery found that large diameter metal-on-metal total hip replacements may be associated with a substantially higher incidence of Pseudotumor formation.
The study which was conducted by researchers at Isala Kliniek hospital in the Netherlands looked at a total of 119 patients who underwent 120 metal-on-metal total hip replacements with large-diameter femoral heads between January 2005 and November 2007. The research team obtained outcome scores, serum metal ion levels, radiographs and CT scans for all of the patients. Patients with symptoms or unidentified Pseudotumor were then offered MRI and an ultrasound-guided biopsy.
Out of 108 patients (109 hips) eligible for evaluation by CT scan at a mean follow-up of 3.6 years (2.5-4.5) 42 patients (39 %) were diagnosed with a Pseudotumor. The hips of 13 patients (12 %) were revised to a polyethylene acetabular component with small diameter metal head. Patients with elevated serum metal ion levels had a four times increased risk of developing a Pseudotumor.
The term ‘Pseudotumor’ is used to describe a variety of non-neoplastic non-infective lesions in various locations. The term is currently used in arthroplasty of the hip to denote a peri-articular mass caused by an immunological delayed hypersensitivity response to metal particles, characterised by a lymphocyte dominated histological pattern. Symptoms of a Pseudotumor in metal-on-metal hip implant patient depend on its size and location, and may include the following:
- Unexplained pain in the region of the hip
- Clicking or subluxation.
- A swelling of the upper leg.
- Dislocation of the hip joint.
- Nerve palsy.
Because of the high incidence of Pseudotumor seen among patients with large diameter metal-on-metal total hip implant devices, the authors of the study recommended that patients fitted with such devices should be closely monitored for this potential side effect.
Metal-on-metal Hip Implant Side Affects
Hip implant devices are made from a variety of materials including a ceramic-coated ball in a ceramic cup, a metal ball in metal cup, and a metal ball fitted into a polyethylene cup. Metal-on-metal total hip replacements were introduced for their proported advantages over conventional devices such as low rates of wear and increased stability. Use of metal-on-metal hip implants using a large size modular femoral head has become increasingly popular during the last decade, especially in young, mobile patients.
Concerns about all metal hip implants started to mount in 2010, when DePuy Orthopaedics issued a recall of its ASR hip devices afterwards found that they were failing in about 12% of patients within five years. A hip implant should last around 10-15 years.
US Health Authorities began studying all metal hip implants shortly after the DePuy ASR hip implant recall to determine if the devices are shedding dangerous levels of metal ions into patients surrounding tissue and bloodstreams. A number of recent studies have found that the build-up of metal debris can result in tissue damage, the development of cysts and Pseudotumors, premature device failure, the need for revision surger and other long-term health problems.
Metal-on-metal Hip Implant Law Suits.
The controversy starring metal-on-metal hip implants has sparked thousands of law suits against DePuy Orthopaedics and other manufacturers. DePuy ASR hip implant law suits have been consolidated in Federal Court in Ohio. In February multi-district litigation was established in the US District Court for the Northern District of Georgia for law suits involving the all metal wright conserve hip replacement system. Claims involving a metal-on-metal version of DePuy’s hip implant have also been consolidated in a multi-district litigation in Texas. Several law suits are also pending in the US over Biomet metal-on-metal hip implants.
If you have received a metal-on-metal hip implant and have suffered adverse side effects please call Liam Moloney Solicitor today on 045 898000 or simply log on to our website www.moloneysolicitors.ie for further information about your rights to secure compensation.