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Review
. 2021 Apr 16;22(1):356.
doi: 10.1186/s12891-021-04210-y.

Bilateral neck fracture in bimodular femoral stem after primary total hip arthroplasty: a case report

Samo K Fokter  1 , Nenad Gubeljak  2 , Jožef Predan  2 , Jure Sevšek  3 , Jan Zajc  4 , Zmago Krajnc  1
Affiliations
Review

Bilateral neck fracture in bimodular femoral stem after primary total hip arthroplasty: a case report

Samo K Fokter et al. BMC Musculoskelet Disord. .

Abstract

Background: Bi-modular stems were introduced in primary total hip arthroplasty (THA) to enable better control of the femoral offset, leg length, and hip stability. Despite numerous reports on modular femoral neck fractures, some designs are still marketed worldwide. While the risk factors for the sudden failure are multifactorial and mostly known, the timing of this new THA complication is not predictable by any means.

Case presentation: In this report, the literature regarding one of the most popular bi-modular stems with specific neck-stem coupling (oval Morse taper) is reviewed and illustrated with a case of bilateral modular neck fracture in a patient with idiopathic aseptic necrosis of femoral heads treated with primary bi-modular THA. Because of bilateral modular femoral neck fracture, which occurred 3 years on the left side and 20 years after implantation on the right side, the patient required a total of 6 revisions and 208 days of hospitalized care.

Conclusion: To our knowledge, this is the first report of bilateral modular neck fracture in a single patient. Even though the same surgeon performed both operations and used the same neck length and orientation, fractures occurred with a 17-year time difference after implantation. This shows that we cannot predict with certainty when a fracture might occur. Orthopaedic surgeons should use bi-modular stem designs for primary THA very cautiously.

Keywords: Bi-modular femoral stem; Case report; Modular femoral neck; Neck fracture; Taper corrosion; Titanium alloy; Total hip arthroplasty complication.

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Conflict of interest statement

The authors declare that they have no conflict of interest.

Figures

Fig. 1
Fig. 1
Emergency room X-ray of the left hip with fractured modular femoral neck 3 years after primary THA
Fig. 2
Fig. 2
Pelvic X-ray with modular neck fracture shown on the right and situation 1 year after fourth revision of the left THA, respectively
Fig. 3
Fig. 3
Optical photograph of the fractured surface of the modular neck with the distal part still engaged in the conical cavity of the femoral stem
Fig. 4
Fig. 4
X-ray of the right hip 14 months after last revision
See this image and copyright information in PMC

References

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