Implant Tribology

Evaluation of the friction and wear properties of existing bearing materials, and the development of more durable materials for the hip, knee and spinal disc replacements.

Scope
The goal of research in the Implant Tribology Laboratory is to identify the causes of wear in artificial joints, and to develop more durable bearing surfaces to extend their useful lifespan in patients.
Research
Studies based in the Tribology Laboratory may include the evaluation of existing or prototype materials for orthopaedic implants, as well as the fundamental development of new, improved materials. 

The investigators of the Tribology Laboratory comprise one of the most experienced, productive and internationally recognized teams active in this field.
Apparatus
The core equipment of the Laboratory includes a 12-station reciprocating pin-on-disk machine for screening experiments; five hip joint wear simulators totaling 48 test stations; two spine arthroplasty wear simulators (one 3-station, and one 6-station); and a 3-station fretting wear simulator, suitable for modeling wear between non-bearing surfaces such as the stem-cement interface of a hip arthroplasty or backside wear of a knee arthroplasty. Implant materials and wear may be characterized using light microscopy, FTIR, surface roughness, SEM with EDAX, coordinate measuring machine (CMM) and other techniques.
Staff
The Tribology Laboratory is under the direction of Harry A. McKellop, Ph.D., and includes Zhen Lu, Ph.D., Wear Lab Manager, Fu-Wen Shen, Ph.D., and Fabrizio Billi, Ph.D.
Publications
  1. McKellop, H., Park, S.H., Chiesa, R., Doorn, P, Lu, B., Normand, P., Grigoris, P. and Amstutz, H.: In-vivo wear of three types of metal-metal hip prostheses during two decades of use. Clinical Orthopaedics and Related Research. 329S, 128-140, 1996
  2. Lu, Z., McKellop, H.: Frictional heating of bearing materials tested in a hip joint wear simulator. (CeramTec Award Paper) Engineering in Medicine, Proc. Instn. Mech. Engrs., 211, Part H, 101-108, 1997
  3. McKellop, H., Shen, F.W., Lu, B., Campbell, P., Salovey, R.: Development of an extremely wear resistant UHMW polyethylene for total hip replacements. (Kappa Delta Award Paper), J. Orthopaedic Research. 17 (2), 157-167, 1999
  4. McKellop, H., Shen, F.-W., Lu., B., Salovey, R.., Campbell, P.: The effect of sterilization method and other modifications on the wear resistance of acetabular cups of ultra-high molecular weight polyethylene. A hip simulator study. J. Bone and Joint Surgery, 82-A (12), 1708-1725, 2000
  5. Shen, F.-W., McKellop, H.: Surface-gradient crosslinked polyethylene: Oxidation resistance and wear against smooth and roughened femoral balls. Clinical Orthopaedics and Related Research, 430, 80-88, 2005
Contact
Harry McKellop, Ph.D., HMcKellop@mednet.ucla.edu, tel:             (213) 742-1440