Enhancing the mechanical integrity of the implant–bone interface with BoneWelding® technology: Determination of quasi‐static interfacial strength and fatigue resistance

Abstract

The BoneWelding technology is an innovative bonding method, which offers new alternatives in the treatment of fractures and other degenerative disorders of the musculoskeletal system. The BoneWelding process employs ultrasonic energy to liquefy a polymeric interface between orthopaedic implants and the host bone. Polymer penetrates the pores of the surrounding bone and, following a rapid solidification, forms a strong and uniform bond between implant and bone. Biomechanical testing was performed to determine the quasi-static push-out strength and fatigue performance of 3.5-mm-diameter polymeric dowels bonded to a bone surrogate material (Sawbones solid and cellular polyurethane foam) using the BoneWelding process. Fatigue tests were conducted over 100,000 cycles of 20-100 N loading. Mechanical test results were compared with those obtained with a comparably-sized, commercial metallic fracture fixation screw. Tests in surrogate bone material of varying density demonstrated significantly superior mechanical performance of the bonded dowels in comparison to conventional bone screws (p < 0.01), with holding strengths approaching 700 N. Even in extremely porous host material, the performance of the bonded dowels was equivalent to that of the bone screws. For both cellular and solid bone analog materials, failure always occurred within the bone analog material surrounding and distant to the implant; the infiltrated interface was stronger than the surrounding bone analog material. No significant decrease in interfacial strength was observed following conditioning in a physiological saline solution for a period of 1 month prior to testing. Ultrasonically inserted implants migrated, on average, less than 20 microm over, and interfacial stiffness remained constant the full duration of fatigue testing. With further refinement, the BoneWelding technology may offer a quicker, simpler, and more effective method for achieving strong fixation and primary stability for fracture fixation or other orthopaedic and dental implant applications.

Evaluation of using ultrasound welding process of biodegradable plates for fixation of pediatric mandibular fractures

“…The introduction of Sonic Weld with biodegradable plates claiming that it will augment the mechanical properties and fracture stability giving the opportunity to replace the metallic plates in fixation of mandibular fracture [13]. However little literature are available on this point and so accordingly we planned this study to evaluate using of ultrasound based welding process for fixation of biodegradable plates in pediatric mandibular fractures.…”

Refixation of osteochondral fractures by ultrasound-activated, resorbable pins

“…In these cases the complete fragment did not heal and the osteotomy gap was still visible. Ferguson et al 36 demonstrated greater anchoring of ultrasound-activated pins, compared with non-ultrasound-activated, resorbable implants. But their biomechanical tests were performed without the effect of synovial fluid and direct shear forces.…”

Primary stability and osseointegration of dental implants in polylactide modified bone – A pilot study in Goettingen minipigs

“…The BoneWelding ® technology is an ultrasound-based method to anchor bioresorbable plates and meshes to the bone using thermoplastic polymer pins . Due to ultrasonic vibrations, the polymer is temporarily liquefied, filling the cavities of spongious bone and improving the anchoring compared to conventional screw systems (Eckelt et al, 2007;Ferguson et al, 2006;Pilling et al, 2007). Different preclinical studies (Arnoldi et al, 2012;Heidenreich et al, 2011;Langhoff et al, 2009) describe the use of 70/30 poly(L-lactide-co-D, L-lactide) with the BoneWelding ® technology.…”