The authors present their experience using osteogenic protein 1 (OP-1; “Osigraft”) in the treatment of recalcitrant atrophic pseudoarthrosis (PA) of the limbs in patients in whom osteosynthesis surgery failed at least two to four, and more, times. All patients with PA who were treated showed a preoperative radiographic pattern of severe bone atrophy surrounding the peri-fracture zone, without evident signs of reparative activity. All osteosynthesis hardware showed clear evidence of mechanical failure (rupture or mobilisation) so they were changed in all patients during the surgery. From January 2003 to February 2004 we used Osigraft to treat 10 patients with an atrophic PA at the following level: two femurs, three humera, one forearm, three tibiae (1/4 distal) and one tibia (1/3 medium). Osigraft was associated in seven patients with an autograft and in three patients with an allograft plus platelet growth factors (one distal femur, one distal tibia and one humerus). Mean age of patients was 38 years (range: 22–54) and mean duration of disease from the initial trauma was 36 months (range 26–40).

The radiological aspect of the newly formed bone, both endostal and periostal, was very similar to that observed in primary healing, with an inter-fragmentary callus as observed in similar cases treated since the beginning with the most appropriate therapy and that healed after the first operation. In all cases we observed healing of the PA focus in a time period of 6–11 months (mean 8.5) with a satisfactory functional recovery in eight cases; in two cases residual articular stiffness, one knee and one ankle, will require arthroscopic surgery.

Because of the limited number of patients treated with this new method, we can only draw preliminary conclusions. However, compared with our previous experience, we can confirm that Osigraft (OP-1) significantly contributes to bone healing whenever biological reparative potential is strongly compromised because of the type of original trauma, the long time elapsed since then and the many preceding surgeries. Healing times, even if they appear to be quite long, are actually short considering the severity of our cases, usually requiring further surgery for PA not healing after the third intervention (more than 30 %) and cured, if reached, in 12–18 months.

Aims: Both partial and total functional disorders of spine are one of the most disabling, common and costly problem of current surgery. The surgical treatment may involve the partial or total resection of the Intervertebral Disc (IVD). Thus, implants for vertebral fusion are often required in order to immobilize the diseased column.

Cage implants are designed in order to separate contiguous vertebrae allowing an adequate stress transfer and favoring bone growth. In this paper the biomechanical and histological properties of novel composite cages and commercial titanium implants have been in vitro and in vivo investigated.

Materials: Novel composite lumbar cages were designed by F.E.M., manufactured and implanted in porcine spine at the L4-L5 lumbar zone of five pigs (large white-duroc race of 50–55 Kg by weight and 1.9–2.1 months old). Each composite cage was prepared by filament winding technology by using PEI (PolyEtherImmide – GE Polymerland ULTEM 1000/1000) as matrix and Carbon fibre (Torayca T400-B 6000-50B) as reinforcement with a winding angle of 45A1 degree. Mechanical properties were investigated according to ASTM standard on composite material, novel composite cage, titanium cage and the natural disc. The device was coated with PEI – HA (hydroxyapatite) solution in order to improve the bone interaction. The behaviour of the composite cage was compared to titanium lumbar cages (SOFAMOR Danek) through biomechanical and histological tests.

Results: Tensile test performed on composite material have showed a Young’s Modulus equal to 40,1 GPa, maximum tensile strength equal to 602 MPa. Compressive test on the composite cage showed an Elastic Modulus value of 22 GPa. The comparison among the three systems displayed comparable compliance for titanium (0,0014mm/mm) and composite cage (0,0031mm/mm) while an higher compliance in the case of natural disc (0,0521mm/mm). All pigs showed good health up to the sacrificing date. Particularly, histological tests after two months from the implantation already showed abundant the presence of new-formed tissue around the composite cage.

Conclusions:. The results demonstrate that PEI reinforced with Carbon fibres composite cages coated with HA show excellent performance. Mechanical properties of the composite cages are closer to the properties of cortical bone than those of titanium cages, thus reducing the effect of stress concentration and stress shielding and as observed for stiff metal implants.