Table 1.
Case characteristics and treatment strategies applied to achieve bone healing.
| Case number (patient age) | Anatomical site (index trauma) | Bone defect morphology at the time of scaffold implantation (defect volume∗) |
|---|---|---|
| Case 1 (23 years) | Distal femur metaphysis (grade III open fracture) | Extensive non-union with bone shortening causing a leg length discrepancy of −4 cm (73.67 cm3∗∗) |
| 0 months after index trauma | External fixator and treatment of local infection | |
| 2 months after index trauma | Procedural change to less invasive stabilization system (LISS, Synthes®) plate | |
| 6 months after index trauma | Open biopsy and initiation of IMT | |
| 7 months after index trauma | Replacement of the LISS plate by a longer Non-Contact Bridging (NCB, Zimmer®) plate plus implantation of a Locking Compression Plate (LCP, Synthes®) medially along with insertion of a tubular mPCL-TCP scaffold loaded with Cerament G® (BONESUPPORT AB) and RIA ABG | |
| 8 months after scaffold implantation | Unrestricted pain-free ability to walk without the support of assistive devices; advanced bony fusion on radiographic imaging | |
| Case 2 (27 years) | Tibia shaft (grade III open fracture) | Extra-large 10 cm-sized segmental defect (47.13 cm3) |
| 0 months after index trauma | External fixator and treatment of local infection | |
| 0–5 months after index trauma | Partial resection of the tibia during a complicated course of treatment | |
| 6 months after index trauma | Implantation of an Orthofix® external fixator (TrueLok™ Ring Fixation System) and initiation of IMT | |
| 7 months after index trauma | Replacement of PMMA spacer by a tubular scaffold loaded with RIA ABG and Cerament G® (BONESUPPORT AB) and supplemented with rhBMP-2 | |
| 12 months after scaffold implantation | Replacement external fixator with medial angular stable plate | |
| 19 months after scaffold implantation | Bony fusion on CT scan | |
| 23 months after scaffold implantation | Implant removal; pain-free full weight bearing within 2 weeks | |
| Case 3 (42 years) | Femur shaft (complex multi-fragmentary fracture) | Complex malunion (165.72 cm3) |
| 0–5 months after index trauma | Initial treatment with external fixator and large fragment plate | |
| 6 months after index trauma | Open biopsy with septic debridement and fistula revision | |
| 6–7 months after index trauma | Removal of the atypically inserted plate, sequestrectomy, and exchange of the external fixator with a lateral femoral hybrid fixator (Orthofix®) as well as a Vacuum Assisted Closure (VAC) therapy including its regular exchanges | |
| 19 months after index trauma | Implantation of modular (two parts) 3D-printed mPCL-TCP scaffolds loaded with ABG and combined with plate osteosynthesis | |
| 6 months after scaffold implantation | Radiographically confirmed relevant osseous consolidation; pain-free full weight bearing using forearm crutches | |
| 9 months after scaffold implantation | Radiographically confirmed progressing bony fusion | |
| Case 4 (30 years) | Distal tibia metaphysis (complex multi-fragmentary lower leg fracture) | Irregularly shaped large defect (29.89 cm3) |
| 0–4 months after index trauma | External fixator (tibia) and small diameter intramedullary wire (fibula) | |
| 5 months after index trauma | Open biopsy | |
| 5 months after index trauma | Change external fixator to an Orthofix® ring fixator (TrueLok™ Ring Fixation System) and insertion of Cerament V® (BONESUPPORT AB) into the medullary cavity | |
| 19 months after index trauma | Procedural change to intramedullary nail fixation | |
| 20 months after index trauma | Early nail removal due to recurrent osteomyelitis | |
| 21 months after index trauma | External fixator and initiation of IMT | |
| 22 months after index trauma | Placement of LCP 3.5 (Synthes®) and implantation of two-part mPCL-TCP scaffold loaded with iliac crest and RIA ABG as well as Cerament V® | |
| 7 months after scaffold implantation | Pain-free full weight bearing using forearm crutches for additional support | |
| 8 months after scaffold implantation | Radiographically confirmed bone formation inside and outside the fully interconnected scaffold architecture | |
∗ Bone defect volume was calculated by segmenting the CT image data and performing Boolean subtraction from an idealised intact bone volume.
∗∗The calculated defect volume is very likely an underestimate of the actual defect volume, as CT data was used for the calculation from a scan with the bone in impacted, shortened plate fixation.