Osseointegration into a novel titanium foam implant in the distal femur of a rabbit

Abstract

A novel porous titanium foam implant has recently been developed to enhance biological fixation of orthopaedic implants to bone. The aim of this study was to examine the mechanical and histological characteristics of bone apposition into two different pore sizes of this titanium foam (565 and 464 micron mean void intercept length) and to compare these characteristics to those obtained with a fully porous conventionally sintered titanium bead implant. Cylindrical implants were studied in a rabbit distal femoral intramedullary osseointegration model at time zero and at 3, 6, and 12 weeks. The amount of bone ingrowth, amount of periprosthetic bone, and mineral apposition rate of periprosthetic bone measured did not differ among the three implant designs at 3, 6, or 12 weeks. By 12 weeks, the interface stiffness and maximum load of the beaded implant was significantly greater than either foam implant. No significant difference was found in the interface stiffness or maximum load between the two foam implant designs at 3, 6, or 12 weeks. The lower compressive modulus of the foam compared to the more dense sintered beaded implants likely contributed to the difference in failure mode. However, the foam implants have a similar compressive modulus to other clinically successful coatings, suggesting they are nonetheless clinically adequate. Additional studies are required to confirm this in weight-bearing models. Histological data suggest that these novel titanium foam implants are a promising alternative to current porous coatings and should be further investigated for clinical application in cementless joint replacement.

Progression of Bone Ingrowth and Attachment Strength for Stability of Percutaneous Osseointegrated Prostheses

“…The initially accelerated bone ingrowth phase has therefore been attributed to the regional acceleratory phenomenon, the injury response to the surgical trauma and implant insertion. This appears to be in line with the observations of other researchers, who also have attributed the early increase in bone apposition or ingrowth to the regional acceleratory phenomenon [36,37,60]. During the 3-month accelerated bone ingrowth phase, newly formed bone filled approximately 48% of total available pore space of the P 2 structure, increasing the stability of the device.…”

Selective laser melting‐produced porous titanium scaffolds regenerate bone in critical size cortical bone defects

“…The osteoconductive properties of porous titanium scaffolds were proven by the fact that more bone had formed in the bone defects treated than in the defects that were left empty. This agrees with previous reports that used a metaphyseal bone defect model in rabbits 14, 21–24. The rat defect model used here allowed for in vivo micro‐CT scanning to monitor bone formation with time.…”

Cancellous Bone Osseointegration Is Enhanced byIn VivoLoading

“…The porous titanium foam implant has previously demonstrated robust osteoconductive properties, resulting in a comparable bone ingrowth to that of conventional sintered beaded implants in a distal femur rabbit model. 30 Previously, our research group developed and used this model to study native cancellous bone adaptation in situ without a porous titanium foam implant. 18,31 These studies directly loaded the cancellous host bone using the implantable loading device.…”