Research

Examination of ten fractured Oxford unicompartmental knee bearings


Reference:

Pegg, E., Pandit, H., Gill, H. S., Keys, G. W., Svard, U. G., O'Connor, J. J. and Murray, D. W., 2011. Examination of ten fractured Oxford unicompartmental knee bearings. Journal of Bone and Joint Surgery - British Volume, 93 (12), pp. 1610-1616.

Related documents:

This repository does not currently have the full-text of this item.
You may be able to access a copy if URLs are provided below. (Contact Author)

Official URL:

http://dx.doi.org/10.1302/0301-620X.93B12.27408

Related URLs:

Abstract

Since the Oxford knee was first used unicompartmentally in 1982, a small number of bearings have fractured. Of 14 retrieved bearings, we examined ten samples with known durations in situ (four Phase 1, four Phase 2 and two Phase 3). Evidence of impingement and associated abnormally high wear (> 0.05 mm per year) as well as oxidation was observed in all bearings. In four samples the fracture was associated with the posterior radio-opaque wire. Fracture surfaces indicated fatigue failure, and scanning electron microscopy suggested that the crack initiated in the thinnest region. The estimated incidence of fracture was 3.20% for Phase 1, 0.74% for Phase 2, 0.35% for Phase 3, and 0% for Phase 3 without the posterior marker wire. The important aetiological factors for bearing fracture are impingement leading to high wear, oxidation, and the posterior marker wire. With improved surgical technique, impingement and high wear should be prevented and modern polyethylene may reduce the oxidation risk. A posterior marker wire is no longer used in the polyethylene meniscus. Therefore, the rate of fracture, which is now very low, should be reduced to a negligible level.

Details

Item Type Articles
CreatorsPegg, E., Pandit, H., Gill, H. S., Keys, G. W., Svard, U. G., O'Connor, J. J. and Murray, D. W.
DOI10.1302/0301-620X.93B12.27408
Related URLs
URLURL Type
http://www.ncbi.nlm.nih.gov/pubmed/22161922PubMedCentral
DepartmentsFaculty of Engineering & Design > Mechanical Engineering
Research CentresCentre for Orthopaedic Biomechanics
RefereedYes
StatusPublished
ID Code30678

Export

Actions (login required)

View Item