Chapter 5 Cancer

Abstract

The widespread use of temporary and permanent implants in the post World War II era has had a dramatic impact on the practice of medicine and on the life of disabled and ill individuals. Nowhere has this been more obvious than in the frequent use of implants to stabilize fractures and replace diseased joints which has revolutionized orthopedic practice and afforded millions of patients levels of function that previously could not be achieved. Although the metal alloys used in these implants exhibit excellent resistance to corrosion, oxidation of these large components ultimately produce free ions, chlorides, oxides, and hydroxides which, in combination with particulate metal matter released by wear and fretting, are released into the surrounding environment. Efforts to improve these alloys have included compositional as well as processing changes. Additionally, modifications have been made to the plastic articulating components in efforts to produce a much more consistent ultrahigh molecular weight polyethylene. The perceived need to improve implant wear and corrosion resistance and alter design has been largely motivated by the excessive soft tissue staining noted by orthopedic surgeons at the time of removal or revision of clinically failed joint arthroplasty. The presence of particulate metal matter, polyethylene, and even fragments of polymethyl methacrylate in local tissue has been confirmed histologically and by direct analysis [1–4]. In spite of all of the modifications made in implant composition, implant fixation, and articulation, biomaterial degradation and release of these products persist [4–7].

Additional Reading

Nyren, O., McLaughlin, J.K. et al. (1995) Cancer risk after hip replacement with metal implants: A population based study. J. National Can. Inst. 87, 28–33.

An extensive review of risk of cancer in 39 154 total hip replacement patients who appeared in the Swedish National Cancer Registry between 1965 and 1983. A review of 60 cancer-specific sites showed an overall, not clinically significant increase of 3% in incidence, slight increases noted for kidney cancer, prostate cancer (in men) and melanoma accompanied by a continuous decline in gastric cancer for both sexes. This would appear to be the definitive review of the risk for developing cancers after total hip replacement arthroplasty.

Brand, K.G. and Brand, I. (1980) Risk assessment of carcinogenesis at implantation sites. Plastic Reconst. Surg. 66, 591–595.

Review of possible foreign body cancer initiation in humans based upon published case reports. The authors conclude that, since the clinical use of prosthetic implants has been popular for more than twenty years and since, extrapolating from animal experience, at least 25% if not 50% of foreign body tumors should have appeared by the time of their publication, there is little risk of such non-chemically mediated tumors occuring in patients.

Gillespie, W.J., Frampton, C.M.A., Henderson, R.J. et al. (1988) The incidence of cancer following total hip replacement. J. Bone Joint Surg., 70B, 539–542.

A New Zealand study of 1358 patients with total hip arthroplasty, for a total of 14 286 patient years. A significant increase in tumors of the hemopoetic and lymphatic systems, accompanied by a significant decrease of cancers of breast (in women), colon and bowel was observed. The authors suggest that these data are evidence for increased immune surveillance, allowing or precipitating hemopoetic and lymphatic tumors but at the same time providing better resistance to the development of soft tissue tumors. The first large scale study of this question.

Visuri, T. and Koskenvuo, M. (1991) Cancer risk after McKee-Farrar total hip replacement. Orthopedics, 14, 137–142.

A study similar to that of Gillespie et al. but on a Finnish patient group (433 patients; 5729 patient years) leading to the same general conclusions. Includes a historical discussion of the carcinogenic properties of various trace elements.

Jacobs, J.J., Rosenbaum, D.H., Hay, R.M. et al. (1992): Early sarcomatous degeneration near a cementless hip replacement. A case report and review. J. Bone Joint Surg., 74B, 740–744.

A review of a patient who developed a malignant fibrous histiocytoma at the site of a cementless total hip replacement five months after implantation and succumbed of diffuse metastases, as is typical for such patients, within one year of presentation. Includes an extensive review of world literature on sarcomas in the vicinity of total hip replacement and suggest the need for an international registry of such case reports.