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Abstract
In revision THA surgeries, distally fixed, extensively porous-coated femoral stems are often used to achieve a solid initial diaphyseal fixation. In this study, we reported two cases of fracture of Solution Stem (DePuy, Warsaw, Indiana, USA) following revision THA in our institute, and aimed to identify some common risk factors for such a rare complication. A female patient suffered from juvenile rheumatoid arthritis (height: 147 cm, weight: 35.0 kg, and body mass index [BMI]: 16.2) received bilateral THA in 1974 at the age of 18. Extended trochanteric osteotomy (ETO) was performed to facilitate the removal of the prosthesis, and a Solution Stem (8-inch in length, 10.5 mm in diameter) was implanted [Figure 1]a. She had an uneventful recovery after the surgery. Since the distal stem had solid bone ingrowth, stress shielding was followed and subsequently aggravated the proximal bone loss. [5] A biomechanical analysis has shown that larger diameter femoral stems achieve greater torsional stability than smaller stems at a given diaphyseal contact length in revision hip arthroplasty, and a minimum diaphyseal contact length of 3 cm or 4 cm is recommended. [2] Both stems had diameters of 10.5 mm. Although the X-rays showed reasonably good contact between the distal stem and femur shaft, given the proximal bone loss, we assume a lager stem (12 mm) would offer better stem-bone contact in the proximal femur, even though much more bone would be sacrificed during canal reaming. Meneghini RM, Hallab NJ, Berger RA, Jacobs JJ, Paprosky WG, Rosenberg AG. Stem diameter...