Hip Pelvis.  2018 Sep;30(3):190-195. 10.5371/hp.2018.30.3.190.

Late Onset Disassembly of a Modular Neck-stem Component after Cementless Hip Replacement without Dislocation: A Case Report and Review of Literatures

• Papaioannou I
• Repantis T
• Baikousis
• Korovessis P

• KMID: 2419515
• DOI: http://doi.org/10.5371/hp.2018.30.3.190

Abstract

Modular femoral prostheses are characterized by a second neck-stem junction. This modularity provides many clinical benefits including hip offset restoration, intraoperative leg length and anteversion adjustment. Although, this extra junction in modular femoral prostheses can contribute to catastrophic consequences like fracture, cold welding, corrosion and fretting of the modularity. However, only few complications related to the modularity itself have been reported in the literature. We report a unique case of neck-stem component dissociation without dislocation of the R-120PCâ„¢ Modular Stem (DJO Surgical). Our 71-year-old obese female patient underwent cementless hip replacement 5 years ago. Following radiographic confirmation of neck-stem dissociation open reduction was performed and wiring fixation was applied to secure the neck to the stem. After reduction and fixation, hip joint was stable, and our patient returned to her daily routine 2.5 months postoperatively. The last follow up was at 12 months after surgery with excellent radiographic and clinical evaluation.

Keyword

Modular hip prostheses; Disassembly; Late onset; Neck-stem component; Dissociation

MeSH Terms

Aged
Corrosion
Dislocations*
Female
Follow-Up Studies
Hip Joint
Hip*
Humans
Leg
Neck
Prostheses and Implants
Welding

Figure

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  Fig. 1 (A) Anteroposterior hip radiogram, demonstrates neck-stem dissociation without dislocation of the head (black arrows). (B) Anteroposterior hip radiogram with traction application. The black arrow reveals the collar of the neck outside of the junction and the red arrow shows the intact distal part, below the neck's collar.

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  Fig. 2 Photo of the neck component demonstrates the corrosion.

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  Fig. 3 Intraoperative image demonstrates the wiring application to the neck of the prostheses and the greater trochanter (black arrow).

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  Fig. 4 Photo of a saw bone demonstrates the figure of eight fixation of the neck to the stem, by using the collar of the neck to secure the junction with the two loops of the wire.

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  Fig. 5 Postoperative anteroposterior hip radiogram after reduction and wiring.

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  Fig. 6 Anteroposterior and profile hip radiogram 12 months postoperatively.

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