Influence of bone morphology and femur preparation method on the primary stability of hip revision stems

TY - JOUR

T1 - Influence of bone morphology and femur preparation method on the primary stability of hip revision stems

AU - Konow, Tobias

AU - Schlieker, Peter J

AU - Lampe, Frank

AU - Ondruschka, Benjamin

AU - Morlock, Michael M

AU - Huber, Gerd

N1 - © 2022 The Authors. Journal of Orthopaedic Research® published by Wiley Periodicals LLC on behalf of Orthopaedic Research Society.

PY - 2023/6

Y1 - 2023/6

N2 - Aseptic loosening is one of the major reasons for re-revisions of cementless revision stems. Insufficient primary stability is associated with bone characteristics and the surgical process. This study aimed to investigate how femur morphology and preparation methods influence the primary stability of revision stems. The Femur morphology was described by the upper femoral curvature (UFC) and an individualized Dorr type classification based on the ratio between the canal-to-calcar ratio (CCR*) and the cortical index (CI*) introduced as the cortical-canal shape (CCS). Manual and powered reaming in combination with helical and straight reamers were used to prepare the bone cavity of 10 cadaveric human femur pairs. Forces during stem impaction were recorded (Reclaim, Depuy Synthes). Micromotion at the bone-implant interface during cyclic axial loading and torsional load to failure was determined. The CCS and impaction forces (R2  = 0.817, p < 0.001) or torsional strength (R2  = 0.577, p < 0.001) are inversely related. CCS did not correlate with micromotion during axial loading (R2  = 0.001, p > 0.999), but proximal femoral curvature did (R2  = 0.462, p = 0.015). Powered reaming and straight reamers led to an improved torsional strength (both: p = 0.043). The Individualized Dorr classification CCS and UFC allows a good estimation of the primary stability of revision stems. For severely curved Dorr type-C femurs, an alternative anchorage method should be considered clinically.

AB - Aseptic loosening is one of the major reasons for re-revisions of cementless revision stems. Insufficient primary stability is associated with bone characteristics and the surgical process. This study aimed to investigate how femur morphology and preparation methods influence the primary stability of revision stems. The Femur morphology was described by the upper femoral curvature (UFC) and an individualized Dorr type classification based on the ratio between the canal-to-calcar ratio (CCR*) and the cortical index (CI*) introduced as the cortical-canal shape (CCS). Manual and powered reaming in combination with helical and straight reamers were used to prepare the bone cavity of 10 cadaveric human femur pairs. Forces during stem impaction were recorded (Reclaim, Depuy Synthes). Micromotion at the bone-implant interface during cyclic axial loading and torsional load to failure was determined. The CCS and impaction forces (R2  = 0.817, p < 0.001) or torsional strength (R2  = 0.577, p < 0.001) are inversely related. CCS did not correlate with micromotion during axial loading (R2  = 0.001, p > 0.999), but proximal femoral curvature did (R2  = 0.462, p = 0.015). Powered reaming and straight reamers led to an improved torsional strength (both: p = 0.043). The Individualized Dorr classification CCS and UFC allows a good estimation of the primary stability of revision stems. For severely curved Dorr type-C femurs, an alternative anchorage method should be considered clinically.

U2 - 10.1002/jor.25481

DO - 10.1002/jor.25481

M3 - SCORING: Journal article

C2 - 36370133

VL - 41

SP - 1283

EP - 1290

JO - J ORTHOP RES

JF - J ORTHOP RES

SN - 0736-0266

IS - 6

ER -