Demineralized bone matrix and human cancellous bone enhance fixation of porous-coated titanium implants in sheep

Abstract

Allogenic bone graft has been considered the gold standard in connection with bone graft material in revision joint arthroplasty. However, the lack of osteogenic potential and the risk of disease transmission are clinical challenges. The use of osteoinductive materials, such as demineralized bone matrix (DBM), alone or in combination with allograft or commercially available human cancellous bone (CB), may replace allografts, as they have the capability of inducing new bone and improving implant fixation through enhancing bone ongrowth. The purpose of this study was to investigate the effect of DBM alone, DBM with CB, or allograft on the fixation of porous-coated titanium implants. DBM100 and CB produced from human tissue were included. Both materials are commercially available. DBM granules are placed in pure DBM and do not contain any other carrier. Titanium alloy implants, 10 mm long × 10 mm diameter, were inserted bilaterally into the femoral condyles of eight skeletally mature sheep. Thus, four implants with a concentric gap of 2 mm were implanted in each sheep. The gap was filled with: (a) DBM; (b) DBM:CB at a ratio of 1:3; (c) DBM:allograft at a ratio of 1:3; or (d) allograft (gold standard), respectively. A standardized surgical procedure was used. At sacrifice 6 weeks after implantation, both distal femurs were harvested. The implant fixation was evaluated by mechanical push-out testing to test shear mechanical properties between implant and the host bone and by histomorphometry. Non-parametric tests were applied; p < 0.05 was considered significant. Mechanical fixation showed that the strengths among the DBM/CB, DBM/allograft and allograft groups were not statistically different. The strength of the DBM group was 0.01 MPa, which was statistical significantly lower than the other three groups (p < 0.05). Histomorphometry results showed that the bone ongrowth in the DBM group was statistically significantly lower than the other three groups, while the volume fraction of new bone showed no significant difference among all the groups. Our data revealed that adding DBM to CB or to allograft resulted in comparable mechanical properties relative to the gold standard, allograft. We found inferior early effects of DBM alone on the fixation of porous-coated titanium implant in this animal model, while the long-term effects have to be investigated. The combination of DBM with CB, which can be used off the shelf, may represent an alternative to allograft. A cost-benefit analysis is necessary before application in clinical trial.

Optimising proliferation and migration of mesenchymal stem cells using platelet products: A rational approach to bone regeneration

“…There are numerous publications reporting on the clinical results of BMP‐2 and BMP‐7 . However, since the withdrawal of BMP‐7 from the market and the license limitation of BMP‐2 to be used for the management of open tibial fractures, other inductive molecules gained popularity such as demineralized bone matrix (DBM), teriparatide, and platelet products (PP) …”

Osseointegration of acellular and cellularized osteoconductive scaffolds: Is tissue engineering using mesenchymal stem cells necessary for implant fixation?

“…In a later study by the same authors using the same animal model, the 2 mm gap was filled with demineralized bone matrix (DBM), DBM with cancellous bone at a ratio of 1:3, DME with allograft at a ratio of 1:3 or allograft (control group). After 6 weeks observation period, results showed inferior early effects of DBM alone compared to the other groups on early fixation of the titanium implants . Using a different approach, Barckman et al used a dog model to implant cylindrical titanium implants into the distal femur creating a circumferential gap of 2.5 mm, as in our study, that was filled with morselized allograft bone with or without fragmented autologous periosteoum.…”

“…After 6 weeks observation period, results showed inferior early effects of DBM alone compared to the other groups on early fixation of the titanium implants. 40 Using a different approach, Barckman et al 41 used a dog model to implant cylindrical titanium implants into the distal femur creating a circumferential gap of 2.5 mm, as in our study, that was filled with morselized allograft bone with or without fragmented autologous periosteoum. After 4 weeks, activity of new bone formation in the immediate vicinity of the periosteum fragments was observed, also suggesting a beneficial trend in adding autologous cells to increase early implant fixation.…”

“…After 5 weeks observation period, the authors reported similar effect on fixation of the implant by autograft and allograft while the hydroxyapatite/collagen composites, with or without bone marrow aspirate, did not have an effect on early fixation of the implants. 39 In a later study by the same authors using the same animal model, 40 the 2 mm gap was filled with demineralized bone matrix (DBM), DBM with cancellous bone at a ratio of 1:3, DME with allograft at a ratio of 1:3 or allograft (control group). After 6 weeks observation period, results showed inferior early effects of DBM alone compared to the other groups on early fixation of the titanium implants.…”

3D perfusion bioreactor‐activated porous granules on implant fixation and early bone formation in sheep

“…Zone 2: from 500 to 2000 µm into the grafted defect. The zones are described in a recent study by Babiker et al The volume fractions of bone, FT, miscellaneous (misc), marrow, and substitute granules of the blinded sections were quantified by point‐counting technique . The sampling probe and size were defined in order to sample 100 “hits” for bone per implant site as previously described by others .…”