Radiographic and histologic data of an autopsy-retrieved femur contain
ing a Prodigy stem (DePuy, Warsaw, IN) in situ for 26 months were anal
yzed. The Prodigy is a porous-coated Anatomic Medullary Locking stem m
odified with a smooth groove, the Redux Groove, on its medial central
portion. This Redux Groove, designed to increase stem flexibility and
decrease periprosthetic bone resorption, decreases the porous surface
area available for bone ingrowth. In this case, however, the decreased
porous area did not affect diaphyseal bone ingrowth. Additionally, al
though there is a concern that the groove will provide a pathway for d
ebris migration, no evidence of debris was found in the tissue at the
groove site. Although the Redux Groove's value in decreasing periprost
hetic bone loss is still uncertain, this case demonstrated less proxim
al bone loss than was reported in similar dual-energy x-ray absorptiom
etry studies of autopsy cases containing Anatomic Medullary Locking st
ems without a groove. Analysis of more cases with longer in situ inter
vals is necessary to determine if the groove decreases resorptive bone
remodeling and if the groove becomes a conduit for particulate debris
migration. It is emphasized that results of this one case may not be
representative of all Prodigy cases.