Patterned CoCrMo and Al₂O₃ surfaces for reduced free wear debris in artificial joint arthroplasty

Abstract

Surface wear of corresponding tribological pairings is still a major problem in the application of artificial joint surgery. This study aims at developing wear reduced surfaces to utilize them in total joint arthroplasty. Using a pico-second laser, samples of medical CoCrMo metal alloy and Al2 O3 ceramic were patterned by laser material removal. The subsequent tribological investigations employed a ring-on-disc method. The results showed that those samples with modified surfaces show less mass or volume loss than those with a regular, smooth surface. Using calf serum as lubricating medium, the volume loss of the structured CoCrMo samples was eight times lower than that of regular samples. By structuring Al2 O3 surfaces, the wear volume could be reduced by 4.5 times. The results demonstrate that defined surface channels or pits enable the local sedimentation of wear debris. Thus, the amount of free debris could be reduced. Fewer abrasives in the lubricated so-called three-body-wear between the contact surfaces should result in less surface damage. Apart from direct influences on the wear behavior, less amounts of free debris of artificial joints should also be beneficial for avoiding undesired reactions with the surrounding soft tissues. The results from this study are very promising. Future investigations should involve the use of simulators meeting the natural conditions in the joint and in vivo studies with living organisms.

Fabrication and characterization of DLC coated microdimples on hip prosthesis heads

“…A deep dimple can be utilized as a reservoir of microsized wear debris. The previous studies indicate that nanosized wear debris is more biologically active especially when under ionized conditions . Therefore, we predict that trapped wear debris into the dimples will be less biologically reactive to the surrounding tissue thus improving the acceptability.…”

“…For example, Amanov and Sasaki reported that Cr‐doped DLC‐coated dimpled specimen exhibited a lower friction coefficient (>50%) and wear rate (>50%) when compared with those of their polished counterparts under oil‐lubricated sliding conditions; this was achieved by the combination of the storage of wear debris in the dimples and having high hardness of the DLC layer. Tarabolsi et al also reported that microdimpled CoCrMo and Al 2 O 3 surfaces significantly reduced the amount of wear debris in artificial joint arthroplasty. However, the combination of microdimple and hard coating such as DLC has not been investigated to the artificial hip joints yet.…”

“…Further to that, a revision hip replacement is always a more complex and costly surgical procedure when compared with the primary replacement, partially because of the need to counteract the bone loss that requires sophisticated anchoring devices fitted to support the prosthesis . Therefore, the implant durability is still a major challenge that needs to be overcome along with the possible biological response from joint‐induced wear debris—both associated with wear rate as well as other material–and patient‐related factors …”

“…Although, The LST oriented dimpled surfaces were found to have an increased hardness, this could be because their fabricated dents were smaller in geometry (diameter: 200 µm, depth 0.5 µm), thus geometrical effect was negligible . A larger and deeper dimple is preferable to hip joint prosthesis because the contact area of hip joint prosthesis is larger (8–10 mm 2 ), and the larger sized wear debris are expected to remove into dimples from the contacting region, and subsequently reducing the third body abrasive and their possible biological effect surrounding tissue …”

Ring-Shaped Surface Microstructures for Improved Lubrication Performance of Joint Prostheses

“…Additionally, electrochemical measurements outlined that the textured surfaces (dimple design) did not affect the corrosion potential of the metal-on-polyethylene (MoP) bearing [17]. It can also be added that these textures can act as wear traps for particles and subsequently improve the life cycle of artificial joints [18][19][20].…”