Fig. 8.

Bose zones of femur indicating the ladder of reconstruction during revision in very young patients. a Diagrammatic representation of implant fixation during revision must be limited to the next zone so that bone is available for successive revision if required. Choice of stem should be respect this principle. Zone 1 = femoral head with neck, Zone 2 = proximal third of femur resembling cone shape, Zone 3a = upper middle third of cylindrical femur, Zone 3b = lower middle third of cylindrical femur, Zone 4 = distal third of femur an inverted cone. b Hip resurfacing indicating fixation only in Zone 1. c Standard primary low-profile taper stem with fixation in zone 2 for failure of hip resurfacing (zone 1). d SROM type modular or short distal fitting stem with fixation in zone 3a for failure of primary low-profile taper stems (zone 2). e Long distal fitting stem with fixation in Zone 3b for failure of short revision stem (zone 3a)