Introduction:

The development of new prostheses due to large resections has offered important opportunities to orthopedic surgeons mainly in oncology. A medline research can easily underline how poor is the international experience about this cases in nonunion: 75 results for megaprosthesis just 7 works in nonunion.

It is proposed the experience of our department, which deals specifically with the treatment of nonunion, in cases of repeated failures to treatment.

One of the most significant problems in the treatment of relapsing nonunion is the consequent worsening of joint function.

Critical bone defects, sepsis, joint fractures and unclear relapsing nonunions are the most common cases for a megaprosthesis treatment.

In these cases, even if it obtains the healing of nonunion the functional result would be presumptively poor. This radiological or clinical situation drove us, in such cases, to drastic solutions following the principles of cancer cases.

We implanted megaprosthesis with either techniques: 1 stage or 2 stages depending on the clinical findings. In nonunion the main decision making was the septic or aseptic status.

Thanks to recombinant DNA technique it is now possible to synthesise recombinant human osteogenic protein 1 (rh OP1), one of the best documented osteogenic proteins. This protein, linked to type 1 collagen as carrier, is the first drug with proven osteoinductive and osteoconductive properties approved for clinical use.

Osigraft (the commercial name of OP-1 and collagen) is also biocompatible, bioresorbable and lacks the risk of disease transmission. In the most challenging non-union, tibial non-union, the drug showed 80% efficacy as autograft with a better tolerability (i.e. lack of donor site complications) also in patients with previously failed autograft. Higher rates of success were also reported in recalcitrant long bone non-unions, i.e. a mean of 5 years of length of disease, incresaed number of previous surgeries.

Osigraft, also considering its physical characteristics, has to be implanted during the surgical procedure, with direct positioning at the non-union site; furthermore, its use is contraindicated in cases of infection of bone and infection/poor condition of surrounding soft tissues.

In our department we have treated up to now five patients with complex non-union of femoral neck and tibia; in three cases serious soft tissue conditions were present (crushing, infected necrosis) and one patient required plastic surgery. In all case we registered complete clinical and radiological healing after 3.5–7 months.

We also describe two cases of closed application of Osigraft, pushing the drug into the non-union site via a holed cannulated nail with the help of a probe under radioscopic control.

For several years now at the Gaetano Pini Institute of Milan, Italy, we have been improving upon an original instrumental protocol (by means of several radiographic examinations and TC) to understand both congenital and acquired deformations of the lower limbs. Thanks to this technique, it is possibile to evaluate the specific degree of the deformation from any perspective, also from the rotational one; it gives us the possibility to state precisely the dysmorphic pathological consequences on the hip, on the knee and on the ankle joints. This tested kind of interpretation also makes it possible to establish more accurate suggestions regarding surgical correction. If this final correction is achieved in more than one phase, it may be possible to improve the surgical treatment if the contemporary action on the three reference spatial planes is considered. We have already collected data on numerous cases of post-traumatic deformations or congenital dysmorphisms studied by several techniques.