Hip Pelvis.  2015 Sep;27(3):179-182. 10.5371/hp.2015.27.3.179.

Fracture of Fully-coated Femoral Stem after Primary Total Hip Arthroplasty for Nonunion of Intertrochanteric Fracture: A Case Report

• Chun YS
• Juh HS
• Cho YJ
• Rhyu KH

• KMID: 2069148
• DOI: http://doi.org/10.5371/hp.2015.27.3.179

Abstract

Femoral stem fracture is an uncommon reason for the failure of total hip arthroplasty, with only 16 cases of fully coated stem fractures reported to date. Here we report a case in which a fully coated primary femoral stem fracture occurred after conversion to total hip arthroplasty for the non-union of an intertrochanteric fracture of the femur. Metallurgic evaluation of the etiology and mechanism revealed that the fracture was initiated by fatigue-related failure and completed by ductile failure on the posterior side of the fracture. Considering the recent trend of treating an intertrochanteric fracture with hip arthroplasty, possible stem failure should be considered, since most patients will have at least one of the known risk factors for stem fracture.

Keyword

Fracture; Cementless; Stem; Total hip arthroplasty

MeSH Terms

Arthroplasty
Arthroplasty, Replacement, Hip*
Femur
Hip
Humans
Risk Factors

Figure

• 

  Fig. 1 (A) Anteroposterior radiograph shows possible non-union of the intertrochanteric fracture and loss of fixation. (B) Four months later, conversion total hip arthroplasty was performed using a fully coated femoral stem.

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  Fig. 2 (A) Anteroposterior and (B) cross-table lateral radiograph of the hip taken in the emergency department 4 years after the conversion total hip arthroplasty show stem fracture at a level lower than the initially deficient area on the medial aspect of the proximal femur. (C) Revision surgery was performed using a distal fixing modular stem with a larger diameter and bone grafts.

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  Fig. 3 (A) The fracture plane of the femoral stem (×8) shows fatigue failure starting from area 'a'. The beach marks (arrowheads) reveal the initiation of fatigue failure. Failure propagated through area 'c' to the area 'd' in counter-clockwise manner. Area 'd' shows ductile failure leading to final separation. (B) The stair-step morphology as seen on scanning electron microscopy (SEM, ×1,000) and the beach mark area ('b' in Fig. 3A) confirm that the initiating mechanism was fatigue failure. (C) Dimple pattern as seen on SEM (×1,200) along the medial area ('c' in Fig. 3A) shows that the final separation was propagated by ductile failure.

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