New alternate bearing surfaces in total hip arthroplasty: A review of the current literature

Abstract

As indications for total hip arthroplasty (THA) have expanded, the incidence of THA has increased among younger patients, who live longer and tend to place more strain on implants via higher activity levels. This demographical shift accentuates the importance of advancing innovation to ensure implant longevity for younger and more active patients. Future innovation, as it pertains to THA components, is likely to focus on modifying implant designs and tribology in conjunction with identification and application of newer biomaterials. By reviewing the literature for development status of various materials and novel design advancements in THA component outside of the standard highly cross-linked polyethylene, this investigation provided an update on the current and future status of design initiatives as they pertain to THA. Though the highlighted alternative bearing surfaces have shown promising and limited, yet encouraging clinical data, they lack larger and longer-term clinical trial results. Further research and innovation is warranted to identify the optimal bearing surface to most effectively accommodate for the trend of younger and more active patients undergoing THA. Implant longevity is crucial if the clinical success of THA is to be maintained.

3Dprinting of high‐strength, porous, elastomeric structures to promote tissue integration of implants

“…Unlike other materials with low elasticity modulus, such as silicone, PCU has high strength (Schneider et al, 2008). Moreover, it can withstand physiologically relevant loads for several million loading cycles with reduced wear compared to the widely used UHMWP (Grieco et al, 2018;St. John & Gupta, 2012).…”

“…Unlike other materials with low elasticity modulus, such as silicone, PCU has high strength (Schneider et al, 2008). Moreover, it can withstand physiologically relevant loads for several million loading cycles with reduced wear compared to the widely used UHMWP (Grieco et al, 2018; St. John & Gupta, 2012). We were successful in 3D‐printing a device with tunable mechanical properties by varying IPPS, effectively providing a way to match the stiffness of native weight‐bearing soft tissues.…”

<p>The MOVE-C Cervical Artificial Disc – Design, Materials, Mechanical Safety</p>

“…The wear rates were reported to be below the described values for polyethylene cups. 27 Low Bioactivity of Wear Particles A comparison of the macrophage response to PCU and cross-linked UHMWPE in the presence or absence of endotoxin showed that cross-linked UHMWPE particles are potentially more proinflammatory to periprosthetic tissue than PCU. 28 It was anticipated that the combination of larger wear particles, less reactivity and lower particle generation rate would make PCU of lower osteolytic risk compared to hard bearings in total hip replacement.…”

“…28 It was anticipated that the combination of larger wear particles, less reactivity and lower particle generation rate would make PCU of lower osteolytic risk compared to hard bearings in total hip replacement. 27,29 Flexibility and Viscoelasticity The viscoelastic mechanical properties of medical grade polycarbonate urethane were assessed by Beckmann et al 2018. 30 Unfortunately, there is no comparative data reported between PCU and the human disc, meaning that PCU behaves viscoelastically but the degree to which this behavior resembles the natural viscoelasticity of human tissue remains open.…”

Biological Reactions to Metal Particles and Ions in the Synovial Layer of Mice

“…Due to their excellent biocompatibility and mechanical properties, these alloys have been widely employed in implant devices that replace hard tissue in the human body [4]. Since the mid-1980s, over one million metal-on-metal (MoM) hip endoprostheses made from a CoCrMo alloy have been implanted worldwide [5].…”