Femoral shaft fracture in porous and press-fit total hip arthroplasty.

Press-fit and porous femoral components for total hip replacements are currently designed for aggressive canal filling. The bulk of the implants and their manner of insertion have created new femoral fracture problems in hip arthroplasty. Sixteen femoral fractures occurred in a series of 79 press-fit or porous arthroplasties in 72 patients. All cases in this report were reviewed through the period of fracture healing. The fractures were classified as follows: type I, at the neck medially, or proximal to the isthmus laterally; type II, running in a spiral oblique pattern from the stem tip; type III, originating in stress risers in the femoral shaft; and type IV, miscellaneous unclassifiable fractures. All fractures healed, leaving painless hips (Harris hip score average, 84). Collared implants are recommended in proximal fractures to protect against acute subsidence due to a wedging mechanism.