[Shaft revision. Classification and treatment].

The goal of every hip revision is to restore as much function as possible. Frequent problems are defects of the load-carrying bony substance and functional deficits due to trochanteric avulsions, abductor insufficiencies, and lesions of the superior gluteal nerve. Disturbed functions of these important structures may lead to unsatisfactory results with high dislocation rates and limping. Various femoral defect classifications differ in their description of the lesion as well as in their proposed therapeutic approach. Significant differences exist in the field of allograft use. Among others, the AAOS, SO.F.C.O.T, and Paprosky's classifications are described. Our own easy to use alternative classification is introduced which takes into consideration the fixation principle of the new stem. It thus helps to select the type of implant and offers a guideline for technical modalities. A Type 1 defect allows a revision with a component suitable for a primary case. Type 2 defects can be treated with a short revision stem exceeding the length of the revised stem. Type 3 defects are treated with a "load-sharing" concept where an optimized metaphyseal fill and a cylindrical shape distally share the axial and torsion loads. Type 4 defects are reconstructed with a combination of a revision stem and an allograft.