Recombinant human bone morphogenetic protein-7 for treatment of long bone non-union: an observational, retrospective, non-randomized study of 105 patients

Introduction: Autogenous bone-grafting is frequently used in the treatment of fracture non-union. The donor-site morbidity and potentially limited supply of suitable autogenous bone are commonly recognized drawbacks. Recent studies advocated the benefit and safety of recombinant human bone morphogenetic protein-7 (rhBMP-7) in several anatomical sites. An observational, retrospective, non-randomized study on the use of BMP-7 in treating non-union in various sites has been carried out by the BMP-7 Italian Observational Study (BIOS) Group. Materials & Methods: The clinical series included 105 patients. The tibia was the most common site involved (44%). Atrophic/oligotrophic non-unions were noted in 85% of cases. In 46% of cases, the original injury was an open fracture. The average number of previous surgeries for non-union was 2.2 (range 0-13 surgeries). Autologous bone graft was used previously in 23.8% of the cases. Radiographic and clinical assessments were carried out at progressive time intervals on the followings groups: BMP-7 + autograft (A: 50 patients) or BMP-7 (B: 49 patients) or BMP-7 with composite grafts in 6 cases. Treatment was defined as successful when there was a return to normal daily activity with no associated pain and X-ray evidence of new bone bridging the fracture site on more than one radiological view. The results from groups A and B were analysed focusing on the following variables: time of union, previous complications, the number of previous surgeries, previous autograft. The cases treated with a composite graft were excluded, because they were not comparable due to the complexity of the treatment. Results: The mean follow-up was 29.2 months. The last assessment showed an 88.8% success rate with an average healing time of 7.9 months (2-21). At ≥9 months there was overlapping between the unions recorded in the two groups (PA-PB = 1.5%; CI 95%: -0.149; 0.119) for all the variables considered. Discussion: The study shows the efficacy of BMP-7 in the treatment of non-unions even in cases where it was previously used autologous bone graft. The observational nature is a limitation of the present study. Prospective, randomized and controlled studies are necessary for evaluating the efficacy of BMP-7 to improve the performance of autografts and allografts. Conclusions: BMP-7 is a valid alternative to autologous bone graft for the management of complex cases of non-unions.