Session 14: Revision THA—Wear and Osteolysis: CaseBased Panel Discussions
Learning Objectives
Upon completion of this activity, participants should be able to:
1. Understand the relationship between wear and bone resorption.
2. Understand the issues surrounding component retention and lesional treatment
compared to implant removal and revision surgery for osteolysis with well-fixed
implants.
Moderator
William J. Maloney, MD
Elsbach-Richards Professor of Surgery
Professor and Chairman
Department of Orthopaedic Surgery
Stanford University School of Medicine
Stanford, California
Revision THA—Wear and Osteolysis: Case-Based Panel Discussion
Update on Wear and Osteolysis
William J. Maloney, MD
Introduction: The so-called alternative bearings have been available for hip replacement
in North America for more than 5 years. The goal was to reduce wear volume and
therefore reduce the particle load. The hypothesis was that a reduction in the particle load
would reduce the prevalence of osteolysis and revision surgery. We now are beginning to
accumulate sufficient clinical data to address this hypothesis.
Highly Cross-Linked Polyethylene: Every major manufacturer offers a highly crosslinked polyethylene. Differences exist between materials based on manufacturing and
sterilization protocols, thus each requires independent evaluation. Prospective, ongoing
trials are currently being performed on most products. From a surgeon and patient
perspective, the data to date are encouraging. Clinical wear rates have been low and, in
general, have mirrored the laboratory studies. Trials comparing highly cross-linked
polyethylene to conventional polyethylene (gamma-irradiated and package in an inert
environment) demonstrate a significant reduction in wear and osteolysis with the crosslinked material. The process of cross-linking reduces the mechanical properties, and
Session 14
fracture has been reported. In general, the fractures occur in malpositioned sockets, and
socket design likely plays a role.
Ceramic-on-Ceramic: Ceramic-on-ceramic is an extremely low-wear articulation.
However, technically, it is less forgiving in terms of implant positioning. Fracture,
although reduced with modern manufacturing techniques, still exists. Squeaking has
emerged as a problematic clinical issue and has been reported in over 10% of patients in
one series. In addition, ceramic articulations offer less intra-operative options in terms of
head size and neck length. Newer materials and designs will increase product options but
will require clinical data to ensure safety and efficacy.
Metal-on-Metal: Like ceramic-on-ceramic bearings, metal-on-metal articulations are
extremely low-wear surfaces. Like highly cross-linked polyethylenes, there are
manufacturing differences between products that may be clinical have clinical
ramifications. Emerging data suggest that a subset of patients exhibit a reaction to metal
particles/ions that can cause pain and result in significant soft tissue necrosis. One study
reported a 1% prevalence of pseudotumor formation in patients with metal-on-metal
resurfacing. There appears to be a gender bias favoring females over males in terms of a
pathologic reaction.
References:
1. Digas G, Kärrholm J, Thanner J, et al. 5-year experience of highly cross-linked
polyethylene in cemented and uncemented sockets: two randomized studies using
radiostereometric analysis. Acta Orthop. 2007;78(6):746-754.
2. Bitsch RG, Loidolt T, Heisel C, et al. Reduction of osteolysis with use of
Marathon cross-linked polyethylene. A concise follow-up, at a minimum of five
years, of a previous report. J Bone Joint Surg Am. 2008;90(7):1487-1491.
3. Capello WN, D’Antonio JA, Feinberg JR, et al. Ceramic-on-ceramic total hip
arthroplasty: update. J Arthroplasty. 2008;23(7 Suppl):39-43.
4. Pandit H, Glyn-Jones S, McLardy-Smith P, et al. Pseudotumours associated with
metal-on-metal hip resurfacings. J Bone Joint Surg Br. 2008;90(7):847-851.
5. Willert HG, Buchhorn GH, Fayyazi A, et al. Metal-on-metal bearings and
hypersensitivity in patients with artificial hip joints. A clinical and
histomorphological study. J Bone Joint Surg Am. 2005;87(1):28-36.
Case Presentations and Discussion
James A. D’Antonio, MD; David G. Lewallen, MD; Harry E. Rubash, MD; Timothy
Wright, PhD
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