BONE MARROW GRAFT FOR THE TREATMENT OF LONG BONE NONUNIONS

Abstract

Purpose: Local factors such as poor vascular supply, open fracture, or infection can affect the potential for bone formation after fracture, arthrodesis or distraction. The fundamental principal for the treatment of late healing or nonunion is to supplement the local supply of the elements necessary for bone maturation. Centrifuged bone marrow is known to have a osteogenic effect in the treatment of femoral head necrosis or as a complement to conventional grafts. We examined the effect of bone marrow grafts used with conventional grafts.

Material and methods: This retrospective analysis included 14 cases where centrifuged bone marrow graft was used as complementary treatment for post-traumatic nonunion (10 cases), distraction callus (three cases) or late healing after arthrodesis (one case). Bone marrow (300 ml) was harvested from the posterior iliac crest then centrifuged to isolate the maximum number of nucleated cells and stem cells. The centrifugate (60–80 ml) was injected into the fracture site with a trocar during the same operative time. Cell concentrations (total nucleated cells, stem cells (CFU-GM), fibroblastic colonies) were noted. Patients were followed at regular visits. Bone healing was considered to be acquired when weight-bearing was possible without fixation or immobilisation.

Results: Definitive bone healing was achieved rapidly in two cases. Two patients required a conventional graft of a nonunion to achieve consolidation. For six patients, consolidation could not be achieved (three nonunions and three distraction calluses). Final outcome was good or very good in 57% of the cases. Mean delay to bone healing was 6.5 months. The infectious context had no effect on the method. The mean number of nucleated cells injected was 3.9•109 cells in successful cases and 2.8•109 cells in unsuccessful cases. These concentrations affected outcome.

Discussion: This technique for stimulating bone maturation by supplying bone generating cells is indicated for late healing or recent nonunion. It is less effective for distraction calluses or for very old nonunions. Morbidity and iatrogenic effects are minimal. A rigorous harvesting method is required since the result is highly dependent on the cell concentrations and the number of injected cells. Bone marrow injections after centrifugation should be greater than 85 ml and have a cell concentration around 45•106 cells/ml. The method is less successful for old injuries and in patients with arteritis.

Conclusion: Bone marrow grafts are indicated for the treatment of late healing or recent nonunion. Morbidity is low but a rigorous harvesting method is required. The method should be implemented shortly after the fracture without waiting for potential signs of nonunion.