The pseudo A(LT) periprosthetic fracture: it's really a B2

Periprosthetic fracture of the proximal femur involving the lesser trochanter (the Vancouver type A(LT)) is an uncommon occurrence. As it is basically an avulsion fracture of the attachment of the iliopsoas, it does not destabilize the stem and can be treated nonsurgically. In contrast, there is a so-called type "new B2" periprosthetic fracture of the lesser trochanter, which includes a segment of the proximal medial femoral cortex. This is usually seen within 6 weeks of the index procedure, typically following insertion of a tapered, cementless stem within a demineralized femur. This may be due to an unrecognized intraoperative fracture that subsequently displaced under load, or it may occur soon after, during rehabilitation. It is important to distinguish this fracture from the type A(LT), because it is associated with destabilization of the stem and requires early reintervention. The principles of treatment depend on the timing of the fracture and the size of the medial fracture fragment. If recognized intraoperatively as a nonpropagated cortical crack, then extraction of the broach or stem followed by cerclage cable fixation and reinsertion of the stem is adequate in most cases, with protected weight bearing for 6 weeks. If diagnosed postoperatively, or if the fracture fragment is larger, then management with a stem that gains fixation distal to the fracture is required. This distinction between the pseudo type A(LT) and the type "new B2" is important to recognize if appropriate treatment is to be prescribed and a satisfactory outcome is to be assured.