Long-term survival of cemented distal femoral endoprostheses with a hydroxyapatite-coated collar: a histological study and a radiographic follow-up

Melanie Jean Coathup, Vineet Batta, Robin C Pollock, William J Aston, Stephen R Cannon, John A Skinner, Timothy W R Briggs, Paul S Unwin, Gordon William Blunn

Research output: Contribution to journalArticlepeer-review


BACKGROUND: The objective of this study was to examine the degree of osteointegration into a hydroxyapatite-coated collar and relate this finding to aseptic loosening in patients with a distal femoral replacement used to treat primary bone cancer. Our hypothesis was that the implant collar would increase osteointegration and reduce the rate of aseptic implant loosening.

METHODS: Sixty-one patients treated with a primary cemented distal femoral prosthesis between 1992 and 2001 were included in this study. The mean duration of follow-up was 8.5 years (range, two to eighteen years). Extracortical bone growth into the grooved hydroxyapatite-coated collar was quantified radiographically. Histological sections through four hydroxyapatite-coated collars and four implants with no collar, retrieved following amputation due to local recurrence or at autopsy at a mean of 3.5 years (range, 1.4 to 6.1 years) after implantation, were evaluated as well.

RESULTS: Five (8%) of the implants were revised because of aseptic loosening, 3% of the implants fractured, and 3% were revised because of infection. Six limbs (10%) required amputation because of local tumor recurrence. On radiographs, osteointegration into the collar was seen to have occurred in 70% of the patients and did not correlate with sex, age, diagnosis, or length of time postoperatively. Histological analysis showed mature lamellar bone within the grooves of the hydroxyapatite-coated collar, and bone was observed in direct contact with the hydroxyapatite coating. Extracortical bone failed to make direct contact with the surface of the implants manufactured without a collar.

CONCLUSIONS: The use of cemented distal femoral massive bone tumor prostheses with a hydroxyapatite-coated collar located at the shoulder of the implant was followed by a low (8%) rate of revision due to aseptic loosening. The use of hydroxyapatite grooved collars may lead to osteointegration of the implant shoulder (collar) and may reduce the rate of aseptic loosening.

Original languageEnglish
Pages (from-to)1569-75
Number of pages7
JournalThe Journal of Bone and Joint Surgery - Series A
Issue number17
Publication statusPublished - 4 Sept 2013


  • Adolescent
  • Adult
  • Aged
  • Bone Neoplasms
  • Coated Materials, Biocompatible
  • Durapatite
  • Female
  • Femur
  • Follow-Up Studies
  • Humans
  • Male
  • Middle Aged
  • Osseointegration
  • Prostheses and Implants
  • Prosthesis Implantation
  • Radiography
  • Treatment Outcome


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