Background: Currently, the treatment of diaphyseal tibial fractures
associated with substantial bone loss often involves autogenous bone-grafting
as part of a staged reconstruction. Although this technique results in high
healing rates, the donor-site morbidity and potentially limited supply of
suitable autogenous bone in some patients are commonly recognized drawbacks.
The purpose of the present study was to investigate the benefit and safety of
the osteoinductive protein recombinant human bone morphogenetic protein-2
(rhBMP-2) when implanted on an absorbable collagen sponge in combination with
freeze-dried cancellous allograft.
Methods: Adult patients with a tibial diaphyseal fracture and a
residual cortical defect were randomly assigned to receive either autogenous
bone graft or allograft (cancellous bone chips) for staged reconstruction of
the tibial defect. Patients in the allograft group also received an onlay
application of rhBMP-2 on an absorbable collagen sponge. The clinical
evaluation of fracture-healing included an assessment of pain with full
weight-bearing and fracture-site tenderness. The Short Musculoskeletal
Function Assessment (SMFA) was administered before and after treatment.
Radiographs were used to document union, the presence of extracortical
bridging callus, and incorporation of the bone-graft material.
Results: Fifteen patients were enrolled in each group. The mean
length of the defect was 4 cm (range, 1 to 7 cm). Ten patients in the
autograft group and thirteen patients in the rhBMP-2/allograft group had
healing without further intervention. The mean estimated blood loss was
significantly less in the rhBMP-2/allograft group. Improvement in the SMFA
scores was comparable between the groups. No patient in the rhBMP-2/allograft
group had development of antibodies to BMP-2; one patient had development of
transient antibodies to bovine type-I collagen.
Conclusions: The present study suggests that rhBMP-2/allograft is
safe and as effective as traditional autogenous bone-grafting for the
treatment of tibial fractures associated with extensive traumatic diaphyseal
Level of Evidence: Therapeutic Level II. See Instructions
to Authors for a complete description of levels of evidence.