Delivery condition: Sterile, ready to use out of the box.
If the patient can be treated using the standard THR implants
extraordinary luxation tendency, very luxoid hips
weakened soft tissue support
insufficient bone stock
A safe salvage solution implant for patients with challenging anatomic circumstances, pre-existing chronic luxation, or revisions and infections
Specific instruments are not required.
Publication, Case Report:
Bipolar - cupless Procedure
J. HNÍZDO, O. POMAHAČ
The cupless head implant THR procedure is an approved method in human medicine, particularly for patients with fractures involving the femoral neck and head, and as an alternative method in THR patients with unusual requirements.
The indications in veterinary medicine are slightly different to those in human patients. In the veterinary field, cupless head implants can serve as a treatment option for chronically luxated hips, patients with insufficient bone stock, cup loosening (both for cemented and cementless cups or in general, when the previously implanted cup needs to be replaced.
Based on the earlier clinical experience gathered with the monopolar (concentric) cupless head concept with one large sphere directly articulating in the bony acetabulum, the bipolar (eccentric) cupless head design improves the clinical outcome dramatically.
The bipolar cupless head design is based on a femoral head comprising a diamond-like coated titanium larger outer sphere, which is articulating in the bony acetabulum and a smaller UHMW-PE inner sphere in combination with a 15mm femoral head on the femoral stem, acting as a second joint inside the outer sphere.
This design solution therefore splits the overall hip joint motion into a movement of the 15mm femoral head inside the bipolar head and a movement of the bipolar head inside the acetabulum. This results in a marked reduction of the movement of the outer sphere and the mechanical irritation of the acetabulum.
Furthermore and importantly, the bipolar design consisting of a slight axial shift of the center of rotation of the inner sphere compared to the outer sphere, results in an overall self-centering mechanism of the cupless head implant inside the bony acetabulum. Suitable cupless head implants for femoral stems of other manufactures are available upon request.