Jonathan Black

Handbook of biomaterial properties

Foreword. Introduction. Contributors. Part I: A1. Cortical bone J. Currey. A2. Cancellous bone T.M. Keaveney. A3. Dentine and enamel K.E. Healey. B1. Cartilage J.R. Parsons. B2. Fibrocartilage V.M. Gharpuray. B3. Ligament, tendon and fascia S.L.-Y. Woo, R.E. Levine. B4. Skin and muscle A.F.T. Mak, M. Zhang. B5. Brain tissues S.S. Margulies, D.F. Meaney. B6. Arteries, veins and lymphatic vessels X. Deng, R. Guidoin. B7. The intraocular lens T.V. Chirila. C1. Blood and related fluids V. Turitto, S.M. Slack. C2. The vitreous humour T.V. Chirila, Y. Hong. Part II: 1. Metallic biomaterials J. Breme, V. Biehl. 1a. Stainless steels. 1b. CoCr-based alloys. 1c. Titanium and titanium alloys. 1d. Dental restoration materials. 2. Composite materials L. Ambrosio, G. Carotenuto, L. Nicolais. 3. Thermoplastic polymers in biomedical applications S.H. Teoh, Z.G. Tang, G.W. Hastings. 4. Biomedical elastomers J.W. Boretos, J. Boretos. 5. Oxide bioceramics in medicine and dentistry J. Li, G.W. Hastings. 6. Properties of bioactive glasses and glass-ceramics L.L. Hench, T. Kokubo. 7. Wear M. LaBerge. 8. Degradation/resorption in ceramics in orthopaedics H. Oonishi, H. Oomamiuda. 9. Corrosion of metallic implants M.A. Barbosa. 10. Carbons A.D. Haubold, R.B.More, J.C. Bokros. Part III: 1. General concepts of biocompatibility D.F. Williams. 2. Soft tissue response J.M. Anderson. 3. Hard tissue response T. Albrektsson. 4. Immune response K. Merritt. 5. Cancer M. Rock. 6. Blood-material interactions S.R. Hanson. 7. Soft tissue response to silicones S.E. Gabriel. Index.

Composition and morphology of wear debris in failed uncemented total hip replacement

Interfacial membranes collected at revision from 11 failed uncemented Ti-alloy total hip replacements were examined. Particles in the membranes were characterised by electron microscopy, microchemical spectroscopy and particle size analysis. Most were polyethylene and had a mean size of 0.53 micron +/- 0.3. They were similar to the particles seen in the base resin used in the manufacture of the acetabular implants. Relatively few titanium particles were seen. Fragments of bone, stainless steel and silicate were found in small amounts. Most of the polyethylene particles were too small to be seen by light microscopy. Electron microscopy and spectroscopic techniques are required to provide an accurate description of this debris.

Release and excretion of metal in patients who have a total hip-replacement component made of titanium-base alloy.

Serum concentration and urinary excretion of titanium, aluminum, and vanadium were measured for patients who had a well functioning cementless primary total hip replacement of one of two different designs, for patients who had a loose total hip replacement that was to be revised, and for control subjects who had no implant. Serum concentrations of titanium were elevated approximately twofold in the patients who had a loose implant, compared with the values for the control subjects. No major differences in terms of urine concentration of titanium, serum concentration of aluminum, or urine concentration of aluminum were observed among any of the groups that were studied. Concentrations of vanadium were uniformly low in all groups.

Biologic performance of tantalum

A detailed literature search was carried out to define the current knowledge about the biological performance of tantalum. The pure metal appears, to a great degree, to be inert both in vivo and in vitro. Both the pure metal and its principle oxide possess low solubility and toxicity; however, halide compounds are more biologically active. Local host response is benign, characterized by vital encapsulation in soft tissue and frequent osteointegration, reminiscent of titanium, in hard tissue. Tantalum has been in clinical use since before 1940 and has found a wide range of diagnostic and implant applications, with apparently overall excellent results. In some applications, such as for radiographic bone markers and cranial closure, tantalum may well be the current material of choice. In summary, metallic tantalum is a promising biomaterial whose applications have been limited by technical rather than biological performance considerations.

Metallosis associated with a stable titanium-alloy femoral component in total hip replacement. A case report.

Metallosis is usually defined as aseptic fibrosis, local necrosis, or loosening of a device secondary to metallic corrosion and release of wear debris’2. It has been an occasional but characteristic clinical finding in patients who have a metal-on-metal design of total hip replacement, such as the McKee-Farrar prosthesis18. The nearly universal adoption of metal-on-polymer designs (following the lead of Charnley’s low-friction arthroplasty) and the more recent introduction of ceramic-on-polymer and ceramic-onceramic22 articulating interfaces have reduced release of metallic debris due to wear sufficiently that this mode of failure of well fixed hip components has been almost eliminated. However, a recent report’ identified metallosis as a contributing factor in the clinical failure of nine total hip replacements that were made of titanium-based alloy and ultrahigh molecular weight polyethylene. Apparently the metallosis was secondary to wear and fretting of the metallic femoral components. We report the case of another patient who had clinical failure of a total hip prosthesis that was made of titaniumbased alloy and ultra-high molecular weight polyethylene and was fixed with polymethylmethacrylate. The failure was due to excessive wear of the metallic femoral head, in the absence of loosening of either component.

Cellular Mediators Secreted by Interfacial Membranes Obtained at Revision Total Hip Arthroplasty

The interfacial membrane between implant and host-bone in aseptically loose total hip arthroplasties has a potential role in the etiology of local bone resorption and loosening of the prosthetic component. Inflammatory/potential bone-resorbing agents (cytokines/mediators) released by the cells of the interfacial membranes of loosened uncemented and cemented total hip arthroplasties were measured. Synovial tissues from patients with acute femoral neck fractures, patients with osteoarthritis, and cadavers without joint disorders were used as control subjects. Control synovial tissue from osteoarthritic patients secreted the highest levels of prostaglandin E2, interleukin-8, and tumor necrosis factor alpha. Interleukin-1 alpha was the only cytokine whose levels were elevated as much as 4-fold around uncemented implants compared with cemented implants, and up to 16-fold compared with control synovial tissue. An apparent inverse relation between interleukin-1 alpha and interleukin-6 interfacial membranes of total hip arthroplasties compared with control synovial tissues suggests a complex cellular mechanism through a cytokine/prostaglandin cascade; this may regulate the observed bone resorption in aseptic loosening.

Size and shape of biomaterial wear debris.

A literature review of wear debris is presented. Included are debris retrieved at revision of total joint replacement and at autopsy, as well as debris produced in vitro in wear testers and joint simulators or otherwise fabricated for biological experiments. Observations of wear debris in vivo and in vitro are classified in tabular form according to material type, origin, size, shape and color. Polymer particles, most commonly ultra-high molecular weight polyethylene (UHMWPE), exhibit the largest size range and appear as granules, splinters or flakes, while ceramic particles possess the smallest size range and have a granular structure. Metal particles seen in vivo and in vitro, whether from cobalt-chromium alloys or, less frequently, other alloys, form granular or needle-like shapes and generally are smaller than polymer particles but larger than ceramic particles. Particles generated in joint simulators resemble the size and shape of in vivo wear particles from total joint replacement (TJR) retrieved at revision or autopsy. However, particles prepared in vitro, whether in simulators or by other means, do not consistently resemble wear debris particles from TJR.

Systemic metal-protein binding associated with total joint replacement arthroplasty

The distribution of titanium [Ti] and chromium [Cr] in serum protein fractions of patients with and without total joint replacements containing Cr and Ti was studied. Three groups were evaluated: 10 patients with cobalt-chromium [CoCr] alloy prostheses and known elevated levels of Cr; 10 patients with Ti containing implants and known elevated levels of Ti; and 10 age matched controls without prostheses. Metal-protein binding was also examined by adding various concentrations of Cr(+3) (CrCl(3)) to control serum. Cr and Ti were bound to serum proteins within specific molecular weight ranges in both patient groups. Two molecular weight ranges were found to bind Cr (at approximately 70 and approximately 180 kDa) in patients with CoCr alloy prostheses, whereas a single molecular weight range (at approximately 70 kDa) was found to bind Ti in patients with Ti alloy implants. This metal-protein binding was reproduced in vitro by adding CrCl(3) at concentrations of approximately 100 and 1000 ppb Cr, which is orders of magnitude higher than that contained in the serum of patients with CoCr alloy implants ( approximately 3 ppb Cr). This suggests that protein binding is initiated in the periprosthetic space where metal concentrations are typically 2-3 orders of magnitude higher than that observed systemically in the serum. In vitro, high molecular weight proteins including immunoglobulins demonstrated the highest affinity to Cr. Determination of specific protein carriers of metal degradation products is an essential component in the assessment of the long-term biological affects of total joint replacement devices.

Competitive binding of chromium, cobalt and nickel to serum proteins

The competitive binding of chromium, cobalt and nickel chloride salts to murine serum proteins was studied in vitro. Individual metal salt solutions and combinations were incubated with 1:20 dilution of murine serum proteins for 24 h. Then free metal was removed by dialysis. The protein bound metal ions were analysed by graphite furnace atomic absorption spectroscopy. This study determined the saturation binding of cobalt and nickel to serum proteins. Murine serum is mostly saturated when cobalt or nickel is added at the concentration of 2 mol of metal to 1 mol of albumin. Chromium and cobalt have similar protein binding affinity, chromium and cobalt bind to protein in proportion to the added concentration ratio. However, nickel shows significant competition for chromium and cobalt binding moieties. This study provides a reference for future research on the biological role and properties of corrosion products.

In vivo wear of Ti6Al4V femoral heads: A retrieval study

The surface characteristics of sixteen monobloc titanium-6% aluminum-4% vanadium (Ti6A14V) femoral components (two of the 6-Ti-28 type and 14 of the 6-Ti-32 type) retrieved after periods of 78-131 months following loosening of the femoral component, as well as two unimplanted controls, were studied. The femoral heads were examined by a combination of noncontact light profilometry, scanning electron microscopy, and energy-dispersive X-ray analysis. No consistent correlations were found between classical surface roughness parameters (average, root mean square, peak-to-valley roughness, and radius of curvature) and any clinical parameter studied (patient gender, weight, and height; primary diagnosis; implantation time; or calculated force applied on the hip joint). This extensive quantitative topographic analysis suggests that wear mechanisms in vivo are complex and that wear of titanium alloy femoral heads is partly attributed to a combination of an imperfect nature of the surface before implantation, removal of the oxide layer causing abrasion of the alloy, subsequent deformation of the bearing surface including polishing, and, to a very small degree, patient parameters.