Fractures of distally-fixed femoral stems after revision arthroplasty

Abstract

We identified five (2.3%) fractures of the stem in a series of 219 revision procedures using a cementless, cylindrical, extensively porous-coated, distally-fixed femoral stem. Factors relating to the patients, the implant and the operations were compared with those with intact stems. Finite-element analysis was performed on two of the fractured implants. Factors associated with fracture of the stem were poor proximal bone support (type III-type IV; p = 0.001), a body mass index > 30; (p = 0.014), a smaller diameter of stem (< 13.5 mm; p = 0.007) and the use of an extended trochanteric osteotomy (ETO 4/5: p = 0.028). Finite-element analysis showed that the highest stresses on the stem occurred adjacent to the site of the fracture. The use of a strut graft wired over an extended trochanteric osteotomy in patients lacking proximal femoral cortical support decreased the stresses on the stem by 48%.We recommend the use of a strut allograft in conjunction with an extended trochanteric osteotomy in patients with poor proximal femoral bone stock.

High Survival of Modular Tapered Stems for Proximal Femoral Bone Defects at 5 to 10 Years Followup

“…It is of interest to note that fracture of the stem can also occur in patients who receive a nonmodular distally fixed cobalt-chrome stem. In a study by Busch et al [4], they noted a fracture rate of 2.3%. Risk factors for fracture included small stem diameter, use of an ETO, and poor proximal bone.…”

Minimally invasive hollow trephine technique is recommended for revision of broken uncemented and extensively porous-coated monolithic femoral stems: a review of three cases

“…[15,16] Inadequate osseous support in the proximal femur has been demonstrated to be a contributing risk factor to femoral stem fracture. [4] In our series, one patient underwent ETO and one patient underwent a cortical window fenestration for cement removal during previous revision surgery.…”

“…[4] Higher body mass index >30, poor proximal femoral bone support and diameter of femoral component <13.5 mm are factors associated with this complication. Modular revision hip systems show a comparable or even higher risk of prosthetic fracture at the mid stem junction, [18] compared to cementless revision monolithic cylindrical stems.…”

“…Good distal fixation actually leads to the fracture in the metaphyseo-diaphyseal junction of femoral component, particularly in the presence of proximal femoral bone loss. [4][5][6][7] Fracture of a revised stem is a result of material fatigue, [4,8] after a course without any complaints. Distal bone ingrowth of the prosthesis and present inadequate bone support [9] in the metaphyseal region leads to increased stress of the revision femoral stem.…”

“…[4,7,9,10] It is possible to perform this procedure using an endomedular approach without femoral osteotomy. Subsequent bone loss is minimized in this procedure ( Figure 1).…”