P044 - A Personalized, Regenerative Implant for Open-Wedge Osteotomy - From Scan to Surgery
- M. Rikkers (Utrecht, NL)
- M. Rikkers (Utrecht, NL)
- H. Nguyen (Utrecht, NL)
- N. Golafshan (Utrecht, NL)
- M. De Ruijter (Utrecht, NL)
- R. Levato (Utrecht, NL)
- L. Vonk (Teltow, DE)
- N. Van Egmond (Leusden, NL)
- M. Castilho (Utrecht, NL)
- R. Custers (Utrecht, NL)
- J. Malda (Utrecht, NL)
Abstract
Purpose
Unicompartmental osteoarthritis of the knee joint can be treated with open-wedge osteotomy. However, the procedure faces several challenges as postoperative pain and non-union. Here, we aimed to design personalized implants using an osteopromotive and degradable biomaterial, that closes the gap left after an open-wedge osteotomy.
Methods and Materials
An open-wedge osteotomy procedure was preplanned using computed tomography (CT) scans. Based on this, a porous wedge scaffold was designed and printed using a magnesium strontium phosphate-polycaprolactone (MgPSr-PCL) biomaterial ink. The wedges were mechanically characterized and in vitro osteopromotive properties of the material were assessed using expanded human bone marrow-derived mesenchymal stromal cells (MSCs) and bone marrow concentrate (BMC). Next, personalized implants were fabricated for ex vivo implantation in three osteotomies with different heights (5 mm, 10 mm, 15 mm), and the wedges were implemented into the standard osteotomy surgical procedure in human cadaveric legs.
Results
Personalized wedge implants with inter-fibre spacing (IFS) of 0.7 mm, 1.0 mm, and 1.3 mm with closed outer edges were fabricated (Figure 1). Implants with IFS-1.0 resulted in scaffolds that maintained top and bottom porosity, while exhibiting significant mechanical stability. MSCs and BMC cells attached to the MgPSr-PCL material and proliferated over 21 days in culture. Alkaline phosphatase activity, calcium, and osteocalcin production were promoted in all culture conditions, independent of osteogenic induction medium. Finally, three “personalized” wedges were implanted ex vivo during a high tibial open-wedge osteotomy procedure. A small fraction of one side of the wedges were trimmed off to assure fit into the biplanar osteotomy gap. Pre-planned wedge heights were maintained after implantation as measured by micro-CT.
Conclusion
To conclude, we have designed and manufactured personalized implants to fill the gap in open-wedge osteotomies. The implants supported osteogenesis of MSCs and BMC in vitro and were successfully implemented into the surgical procedure, without compromising pre-planned wedge height.