Five-year clinical, radiological and postmortem results of the Cambridge Cup in patients with displaced fractures of the neck of the femur

Abstract

The Cambridge Cup has been designed to replace the horseshoe-shaped articular cartilage of the acetabulum and the underlying subchondral bone. It is intended to provide physiological loading with minimal resection of healthy bone. The cup has been used in 50 women with displaced, subcapital fractures of the neck of the femur. In 24 cases, the cup was coated with hydroxyapatite. In 26, the coating was removed before implantation in order to simulate the effect of long-term resorption. The mean Barthel index and the Charnley-modified Merle d'Aubigné scores recovered to their levels before fracture. We reviewed 30 women at two years, 21 were asymptomatic and nine reported minimal pain. The mean scores deteriorated slightly after five years reflecting the comorbidity of advancing age. Patients with the hydroxyapatite-coated components remained asymptomatic, with no wear or loosening. The uncoated components migrated after four years and three required revision. This trial shows good early results using a novel, hydroxyapatite-coated, physiological acetabular component.

Polyaxial Locked Implants in the Treatment of Type Vancouver B1 Periprosthetic Fractures of the Femur: Retrospective Clinical Examination in 58 Cases with Review of the Literature

“…The Barthel index results show that patient independence after periprosthetic femoral fractures is clearly restricted. Again, there are no data for comparison, but the decrease in Barthel index found in this study in patients with a mean age of 72 years is comparable with that seen for patients after hip fracture or arthoplasty with mean ages of more than 80 years [43][44][45]. The mean stand up and go time was measured at about 22 s. Again, there are no data that would enable a direct comparison.…”

PEEK biomaterials in trauma, orthopedic, and spinal implants

“…24/50 implants were coated with hydroxyapatite, the remaining 26/50 cups were uncoated. The HAcoated implants did not exhibit significant wear or migration, but the uncoated implants migrated and 3/26 had to be revised at two years [194]. In a DEXA study of Cambridge cup patients, after two years researchers did not find a significant decrease in periprosthetic bone mineral density, as compared with unimplanted controls [195].…”

“…A novel horseshoe-shaped acetabular component was developed by Mr. Richard Field and Neil Rushton at Cambridge University (Cambridge, UK) with the rationale of duplicating the physiologic load distribution in the natural acetabulum, thereby reducing stress shielding, which can compromise fixation and facilitate wear debris migration into the periprosthetic bone [193][194][195][196]. The acetabular component was fabricated with an outer shell of carbon fiber-reinforced PBT and an inner liner of UHMWPE.…”

The current state of bearing surfaces in total hip replacement

“…168 The clinical results of the original Cambridge Cup design were encouraging. 169 This design, however, had a UHMWPE bearing surface. Shortterm results of the evolution of this design with a CR-PEEK bearing surface are, however, inferior.…”