Augmenting the osseointegration of endoprostheses using laser-sintered porous collars: an in vivo study.
OBJECTIVE
Massive endoprostheses rely on extra-cortical bone bridging (ECBB) to enhance fixation. The aim of this study was to investigate the role of selective laser sintered (SLS) porous collars in augmenting the osseointegration of these prostheses.


METHODS
The two novel designs of porous SLS collars, one with small pores (Ø700 μm, SP) and one with large pores (Ø1500 μm, LP), were compared in an ovine tibial diaphyseal model. Osseointegration of these collars was compared with that of a clinically used solid, grooved design (G). At six months post-operatively, the ovine tibias were retrieved and underwent radiological and histological analysis.


RESULTS
Porous collars provided a significantly greater surface (p < 0.001) for the ingrowth of bone than the standard grooved design. Significantly greater extracortical pedicle formation was seen radiologically around the grooved design (length p = 0.002, thickness p < 0.001, surface area p = 0.002) than around the porous collars. However, the ingrowth of bone occurred from the transection site into the porous structure of both types of collar. A fivefold increase in integration was seen with the SP and a threefold increase in the LP design when compared with G (p < 0.001).


CONCLUSIONS
SLS porous collars allow the direct ingrowth of more bone and are better than current designs which rely on surface ongrowth and ECBB. Cite this article: Bone Joint J 2017;99-B:276-82.
University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
A
A
Mumith
University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
M
M
Coathup
University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
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M
Chimutengwende-Gordon
University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
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W
Aston
University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
T
T
Briggs
University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex HA7 4LP, UK.
G
G
Blunn
D000818:Animals; D020099:Coated Materials, Biocompatible; D017886:Durapatite; D005260:Female; D007834:Lasers; D016348:Osseointegration; D016062:Porosity; D019736:Prostheses and Implants; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012756:Sheep; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D014025:Titanium
D020099:Coated Materials, Biocompatible; D017886:Durapatite; D014025:Titanium
Endoprosthesis; In vivo; Osteointegration; Porous metal; Selective laser sintering