Extended Trochanteric Osteotomy (Eto) for Revision Total Hip Arthroplasty and Reconstruction With a Standard Versus Revision Stem: A Biomechanical Analysis and Clinical Case Series of 19 Patients

ETO is a standard approach for complex femoral revisions, providing excellent exposure to the medullary canal and acetabulum while protecting soft tissue and neurovascular structures. A short ETO may enable reconstruction with standard implants, avoiding modular stems. We routinely use standard stems after ETOs to enhance proximal bone loading, minimizing stress shielding, and reducing cost. This study analyzes the biomechanical stability of standard (STD) versus revision (REV) CORAIL® stems (DePuy Synthes) after ETO and assesses clinical outcomes. An in-vitro SYNBONE®-model compared stability of STD (n=12) and REV (n=12) collared hip stems (size 14, 135°) with an 60mm open ETO. Clinical cases (01.01.2018–31.12.2021) showed ETO lengths of 60–90mm. Axial stability was tested with 500 cyclic loads (20° adduction, 1Hz, 500N) and quasi-static loading to failure (n=6 each). Torsional stability was tested with 500 cycles (10Nm internal rotation, 1Hz) and quasi-static loading to failure (n=6 each). Stiffness (axial N/mm; torsional Nm/°) and peak load (N)/torque (Nm) at failure were recorded. Statistical analysis used One-Way ANOVA (p≤0.05). Clinically, STD implants were used, and the ETO fragment was fixed with two cerclages and either an 8-plate or two trochanteric screws. Follow-ups included PROMs and x-rays. REV showed higher axial stiffness (297.5 ± 39.7 N/mm vs. STD 245.9 ± 33.2 N/mm, p =0.037) and greater peak axial force (1228.1 ± 86.8 N vs. STD 1002.5 ± 114.1 N, p =0.001). Torsional stiffness (STD: 2.11 ± 0.25 Nm/°; REV: 2.38 ± 0.28 Nm/°, p =0.372) and peak torque at failure (STD: 20.1 ± 5.9 Nm; REV: 20.3 ± 3.7 Nm, p >0.999) showed no significant differences. Axial failure with REV occurred at the stem tip, while STD fractures occurred either at the stem tip or through the ETO. Both stems showed spiral fractures at the ETO's distal end under torsion. Clinically, 19 patients (66 ± 8 years; 39% male) with 30 ± 7 months follow-up showed full ETO consolidation, no re-revisions or radiological loosening. PROMs improved: COMI from 7.3 ± 1.3 to 1.3 ± 1.7, OHS from 23 ± 6 to 44 ± 6, UCLA from 3.1 ± 0.8 to 6.3 ± 1.4. REV provides greater axial stability than STD, even with open ETO, while STD maintains axial stability regardless of ETO. Both stems demonstrated comparable torsional stability and peak torque, though ETO reduces rotational stability. Standard stems are suitable for primary and revision surgeries with short ETO, offering a safe, cost-effective alternative to long revision stems or modularity.