Numerous growth factors, together with bone morphogenetic proteins (BMP), are involved in the biological mechanism of bone induction. BMP 7 combined with collagen type 1 has shown to be effective in triggering the osteoinductive mechanism in the presence of bone defects as an alternative to bone graft. The aim of the present study is to present the experience gained at the Orthopaedic Clinic of Catania with BMP in lower limb non-union or pseudoarthrosis with bone defect after skeletal stabilisation.

From December 2003 to May 2004 at the Orthopaedic Clinic Of Catania four patients were treated using OP 1. The study group comprised three women and one man with a mean age at the time of operation of 27 years (range 23– 32 years). One subject presented with non-union, two patients with normotrophic pseudoarthrosis and one with atrophic pseudoarthrosis. In all cases the bone defect was localised at the tibia. All patients were treated surgically with skeletal stabilisation (one with a monolateral external fixator, one with a T2 intramedullary nail and two with a Gross-Kempf nail) always after decortication of Judet.

Three patients healed with a mean follow-up of 5 months. One subject is still under treatment. None of the patients have any pain and demonstrate complete weight bearing and functional capacity. X-rays showed good consolidation of bone defect.

Clinical and radiographic results obtained at this point are more than fair. Healing time was short without any side effects. It is important to verify whether, in the treatment of lower limb non-union and or pseudoarthrosis, the osteoinductive capacity of the OP 1 could provide the same valid results without good reduction and skeletal stabilisation. The use of OP 1 is extremely interesting for many reasons. However, it would be extremely important to test whether the biological effect is not exclusively related to an optimal mechanical stability.

Aims: to evaluate the process of remodelling at the bone-femoral prosthesis interface by using computerized bone mineralometry (CMB)Methods: at the Orthopaedic Clinic, University Catania we performed from January 1992 densitometric studies on uncemented, anatomically shaped, titanium stems with or without hydroxyapatite (HA) coating. Dual energy X-ray densitometry was used to quantify bone mineral concentration and bone mineral density (BMD). Measurements were performed at the calcar and the medial and lateral cortical of the femur which have been previously demonstrated to be areas of stresses transmission in the normal hip. From 1992 to 2001, 148 patients were regularly studied. 76 subjects had a HA-coating stem. Evaluation was performed at 3, 6 and 12 months after operation and then yearly. Results: in all patients a minimal remodeling process (BMD values > 1 gr/cm² ) was observed at the medial cortical and the calcar zones. We noted higher BMD values in the group with HA-coating stem within 24 months after the operation; BMD values were overlapping between the two groups after 24 months. 27 subjects had reduced densitometric values at the calcar and increased BMD at medial and lateral cortical. Conclusions: CMB appears to be a reliable tool to evaluate the interaction at the bone-femoral prosthesis interface. Densitometric values might be helpful to monitor the periprosthetic bone-remodelling process.