The use of extra-long stems in total hip reimplantation.

The authors report their experience in the use of extra-long stems for total hip reimplantations, and they then compare them with the results obtained when short or standard stems were used. The use of the extra-long stem is reserved for special cases, such as those where there is osteolysis extending to the proximal femur and diaphysis, distal diaphyseal fractures, and when the trans-femoral technique is used to remove the stem. A total of 246 prosthetic stem reimplantations were carried out between 1985 and 1999, and in most of the cases (86.2%) the cause of reimplantation was aseptic loosening of the stem alone or of both prosthetic components, while in the remaining cases it involved the sequelae of endoprosthesis or cotyloiditis (8.5%), the sequelae of septic explantation (2.1%), breakage of the prosthetic head and cone wear (1.2%), breakage of the prosthetic stem (0.8%), fracture of the femoral diaphysis on a loosened cemented prosthesis (0.4%), breakage of the prosthetic neck (0.4%), dislocation of the prosthesis (0.4%). A stem equal to or longer than 22 cm had to be used in 13 cases (5.3%), while a short stem (12-13 cm) or a standard stem (17-18 cm) was sufficient in the remaining 233 cases. The results were worse for the extra-long stem group as compared to those for the short/standard group; that is, there was 1 case (7.7%) of septic loosening that resulted in explantation, as compared to 2.6% (6 cases) of explantation resulting from aseptic loosening (3 cases) or septic loosening (3 cases) of the short/standard group. As concerns radiographic assessment, extra-long stems show bone stability in 69.2% of cases, fibrous in 23.1%, and loosened in 7.7%, while 97.7% of short/standard stems show bone stability, 0.9% fibrous stability, 1.4% instability.