The Difference of Material Wettability as Critical Factor in the Choice of a Tribological Prosthetic Coupling Without Debris Release

Abstract

Today, in spite of the long experience acquired in the field of total hip replacements, prosthetic systems are still far from reproducing the natural system. One of the main causes of long term failure is the amount of wear debris produced by the tribological coupling between acetabolar cup and femoral head. The authors carried out experimental research in order to investigate the tribological coupling of various prosthetic biomaterials. Experimental tests were carried out with the pin-on-disc tribometer in dry, water and human serum as lubricant. This study sets new bases for the design of modern hip prostheses: 1. the wettability difference among the materials in tribological coupling, which is the necessary condition to promote efficient lubrication; 2. the use of Peek reinforced with long and unidirectional carbon fibres in the prosthetic field.

Potential for adhesive wear in friction couples of UHMWPE running against oxidized zirconium, titanium nitride coatings, and cobalt‐chromium alloys

“…The contact angles of different liquids with the surfaces are given in Table III, those for oxidized Zirconium and CoCrMo were in good agreement with measurements from Ref. 24. The surface free energy of the counterpart substrates and their polar and dispersive contributions are given in Figure 4.…”

“…A high wettability with water of one bearing partner and little wettability by the other is beneficial for the formation of a lubricating fluid layer in vivo. 24 The wettability of water is similar to that of synovial fluid. 25 Significant differences in the surface free energy between the different counterpart materials were found.…”

“…24. The surface free energy of the counterpart substrates and their polar and dispersive contributions are given in Figure 4.…”

Tribological characterisation of Zr-based bulk metallic glass in simulated physiological media

“…In general, the smaller the contact is, the better the lubrication should be. Borruto et al proposed that the wettability difference between the tribological coupling materials is important to wear behaviour of prosthetic biomaterials [15]. A high wettability difference between coupling materials (hydrophilic-hydrophobic coupling) promotes the efficiency of lubrication, resulting in low wear and a low friction coefficient in the tribological system.…”

Tromboprofilassi in chirurgia ortopedica: nuove prospettive

“…Anche per quanto riguarda gli acetaboli ne esistono di diversi modelli e materiali. La tribologia, disciplina che in ambito ortopedico studia attrito e usura delle protesi, ha permesso di caratterizzare i diversi materiali impiegati nelle artroprotesi in base alla risposta successiva a ripetute sollecitazioni di scivolamento e/o rotazione [16]. Risultati che condizionano la scelta della protesi (impianti e acetaboli) da applicare in funzione della sede e della tipologia di paziente: metallo-polietilene nell'anziano; metallo-metallo nel paziente non più giovane ma ancora attivo; ceramica-polietilene in un vasto numero di casi; e ceramica-ceramica nel paziente giovane e attivo in quanto la ceramica permette di ricostruire un'anatomia molto simile a quella naturale, offre un'ottima biocompatibilità, lubrificazione, non rilascia ioni, non induce fenomeni allergici e rispetto agli altri materiali risente meno dell'usura ( Fig.…”