The increase in life expectancy and the improvement in surgical techniques contribute to the increase in the number of patients who can benefit from surgical treatment. The selection of the patients justifying a surgical solution will be carried out according to the repercussions in daily life, age, general condition, topography and depth lesions but also of the speed of the surgery, aggravation of the hip osteoarthritis.
Principles of total hip arthroplasty
Coxarthrosis, by definition, corresponds to the disappearance of the cartilaginous structures of the femoral head or the acetabulum, resulting in the exposure of the bone tissue in relation to the chondral defects. This situation is at the origin of the pain, then of the limitation of the articular amplitudes. The principle of arthroplasty is to replace the acetabulum and the femoral head, the failing tissues with inert substances so painless, moored in the osseous structures of the pelvis and the femur.
Hip Implant Lawsuit
Marie Napoli, a famous lawyer in Big Apple, talked about the hip implant case in which companies don’t deliver what they promise with the patients. These devices are manufactured by the faulty materials and create infection in the patient’s body.
The technical deficiencies of the first hip prostheses
Without going back over the history, we will recall here the origin of some failures related to the design of the first implants made available to orthopedic surgeons.
Shape and design of implants
Femoral stem forms deviating too much from the anatomical conditions of the hip may have resulted in implant breaks. The use of small femoral head (22 mm) was the cause of a significant number of post-operative dislocations of the femoral head compared to the acetabulum.
For the part used to reconstitute the acetabulum, for many years, polyethylene was the only material used. This substance, with less resistance to the femoral head, generates microparticles linked to wear. The latter can migrate and cause the loosening of the prosthesis, following the appearance of inflammatory reactions with respect to this foreign body represented by the polyethylene microparticles.
Method of attachment to the bone
The anchorage of the prosthesis on both the cotyloid and the femoral slopes was ensured by cementing. The contact between the polyethylene deposits and the prosthetic cement seems to be at the origin of the loosening observed frequently on the first generation prostheses.
Characteristics of current hip prostheses
Shape of prosthesis
The design of the prosthesis is studied to offer an important mechanical strength. It allows to recover articular amplitudes close to the physiological amplitudes with preservation of the muscular force of the articulation. All statistical studies confirm that the use of large-sized femoral heads significantly reduces the incidence of the risk of prosthetic dislocation.
It is pure metal or alloy material. The fixing can be carried out without cementing. The bone anchoring may be favored by a surface having a specific and adapted appearance (porosity, microbead). The surface of the implant in contact with the bone may also be covered with a microcrystalline product promoting osteo-integration (hydroxy apatite). The use of ceramic at the acetabulum makes it possible to remove the polyethylene. This material offers a better resistance for the long term and greatly reduces the mechanical wear and thus the release of harmful particles in the soft parts.
The instrumentation available to place the prosthesis is compatible with the use of so-called minimally invasive technique. The implant makes it possible to place the implant in an optimal way by means of short approaches, reducing the dilapidation of the soft parts. The precision in the placement of the prosthesis constitutes an additional guarantee on the risk of an episode of post-operative dislocation.