Presence of a Nail in the Medullary Canal; Is It Enough to Prevent Femoral Neck Shortening in Trochanteric Fracture?

Abstract

PURPOSE: Presence of a cephalomedullary nail (CMN) in the medullary canal has

been thought as advantageous in the control of femoral neck shortening (FNS) and

lag screw sliding in trochanteric fracture compared to extramedullary fixation

system. However, researches on the factors that influence the degree of FNS after

cephalomedullary nailing are lacking. MATERIALS AND METHODS: We observed 95

patients (mean age, 75+/-2.8 years) with trochanteric fractures who were treated

with a CMN, and evaluated the relationship between FNS and patient factors

including age, gender, fracture type (AO/OTA), bone mineral density, medullary

canal diameter, canal occupancy ratio (COR=nail size/canal diameter), and

tip-apex distance using initial, immediate postoperative, and follow-up

radiography. RESULTS: Univariate regression analyses revealed that the degree of

FNS was significantly correlated with fracture type (A1 versus A3, p<0.001),

medullary canal diameter (p<0.001), and COR (p<0.001). Multiple regression

analyses revealed that FNS was strongly correlated with fracture type (p<0.001)

and COR (p<0.001). CONCLUSION: Presence of a CMN in the medullary canal could not

effectively prevent FNS in patients with low COR and in A3 type fracture.