Session IX - Femur Fractures

*Fractures of the Femur: The Osteogenic Effect of Reaming

P. V. Giannoudis, MD, A. J. Furlong, FRCS, D. A. Macdonald, FRCS, S. J. E. Matthews, FRCS, R. M. Smith, MD, FRCS

St. James University Hospital, Leeds, United Kingdom

Purpose: We performed a retrospective study of reamed (RFN) against unreamed (URFN) nailing procedures for fractures of the femur to compare their osteogenic effect. Specifically we studied the fracture healing time and the development of heterotopic ossification above the greater trochanter in matched groups of patients.

Methods: We reviewed 147 femoral fractures which were treated with locked intramedullary nails, 50 RFN (A.O. universal or Russell-Taylor reconstruction nails) and 97 URFN (A.O. Unreamed femoral nail). We assessed the healing time on a matched group of 27 RFN and 24 URFN cases of diaphyseal fractures after secondary procedures, metaphyseal and pathological fractures were excluded. All were statically locked and followed clinically and radiologically to death, union or established non-union (1 year). Union was defined as circumferential callus in two planes or painless full weight-bearing whichever was the longer. The formation of heterotopic ossification (HO) was studied radiographically at the time of bone healing on 28 RFN and 32 URFN patients (additional non-diaphyseal fractures included). HO was classified by the method of Brumback and graded 0-4.

Results: The groups used to assess the healing time were comparable for all major variables. There was one polytrauma death and one non-union in each group. The mean healing time was 20.5 weeks in the RFN group and 26.9 weeks in the URFN group (p=0.009 Mann-Whitney). There was no significant clinical problem associated with this delay in fracture consolidation. The groups considered for the assessment of HO were comparable with regard to all risk factors previously recognized to be correlated with HO. The incidence of HO after RFN was 35.7% and after URFN 9.4% (p=0.001 Mann-Whitney). HO after RFN was consistently more severe. In two additional cases where the "Unreamed" nail was inserted after reaming for closed femoral shortening, the healing time was 12 weeks and HO was noted in both cases.

Discussion: This study confirms our hypothesis that the healing time after unreamed nailing of the femoral shaft is increased. We also observed that heterotopic ossification above the greater trochanter is rarer after unreamed nailing. It strongly suggests that the reaming process in the femur is osteogenic. No clinical problems were associated with the delay in fracture healing. The data from the two additional patients suggest that the reaming process is more important than the type of nail.

Conclusion: Reaming of the femur is osteogenic, decreasing the healing time but also increasing the risk of heterotopic ossification.