Proximal/Distal Mismatch: Type A and C Femurs

Abstract

Femoral deformity in primary total hip arthroplasty can make restoration of joint biomechanics difficult. The S-ROM (DePuy Orthopaedics Inc., Warsaw, lnd) prosthesis' modular design allows for independent matching of diaphyseal and metaphyseal anatomy. Corrective osteotomy may also be performed because the stem achieves both proximal and distal stability, which resists the micromotion and torsional loads that would otherwise prevent ingrowth. Seventy-three hips were reviewed at a minimum of 10 years' follow-up. Osteolysis was common, occurring in 55% of hips, but no osteolysis distal to thé stem/sleeve junction was present. At mean 12 years' follow-up, the stem remains stable and no failures of the modular junction have been reported.

Vástagos femorales cortos para el reemplazo total de cadera primario en pacientes jóvenes. Resultados clínicos y biomecánicos*

“…No obstante, el potencial stress shielding permanece latente y podría causar una deficiencia masiva de capital óseo femoral, lo que hace que la cirugía de revisión sea un nuevo desafío en el futuro. 73,74 En este sentido, se han diseñado componentes femorales modulares alternativos con recubrimiento proximal y fijación metafisaria, como el S-ROM (DePuy). Aunque este implante permite una adecuada reconstrucción al combinar la anatomía proximal distal, tiene el problema de la modularidad.…”

A high risk of postoperative periprosthetic femoral fracture in Dorr type C femurs: a retrospective cohort study with ten-year follow-up data and a preliminary monochromatic image analysis

“…Standard-length stems were frequently applied in Dorr type C femurs in previous studies. However, some limitations of standard-length cementless stems, such as proximal–distal mismatch 2 , more intraoperative fractures 3 , and loss of bone stock in revision, are highlighted in Dorr type C femurs, which led to our exploration of short cementless stems. Short stems offer specific advantages, including better bone preservation, avoidance of proximal–distal mismatch, lower rates of intraoperative fracture 4 , natural load transfer 5 , smaller incisions, and less stress shielding, and bone resorption 6 .…”