Background: Noncemented revision arthroplasty is often complicated by the presence of bone implant gaps that reduce initial stability and biologic fixation. Demineralized bone matrix has osteoinductive properties and therefore the potential to enhance gap healing and porous implant fixation.
Questions/purposes: We determined at what times and to what extent demineralized bone matrix promotes gap healing and bone ingrowth around a porous implant.
Methods: We inserted porous titanium implants into the proximal metaphyses of canine femora and humeri, with an initial 3-mm gap between host cancellous bone and implants. We left the gaps empty (control; n = 12) or filled them with either demineralized bone matrix (n = 6) or devitalized demineralized bone matrix (negative control; n = 6) and left them in situ for 4 or 12 weeks. We quantified volume healing of the gap with new bone using three-dimensional micro-CT scanning and quantified apposition and ingrowth using backscattered scanning electron microscopy.
Results: The density of bone inside gaps filled with demineralized bone matrix reached 64% and 93% of surrounding bone density by 4 and 12 weeks, respectively. Compared with empty controls and negative controls at 4 and 12 weeks, gap healing using demineralized bone matrix was two to three times greater and bone ingrowth and apposition were up to 15 times greater.
Conclusions: Demineralized bone matrix promotes rapid bone ingrowth and gap healing around porous implants.
Clinical relevance: Demineralized bone matrix has potential for enhancing implant fixation in revision arthroplasty.