J Korean Hip Soc.  2011 Jun;23(2):151-154. 10.5371/jkhs.2011.23.2.151.

Traumatic Disassembly of a Bipolar Hip Prosthesis: A Case Report

• Park BJ
• Kim JO
• Cho HM
• Sim JH

• KMID: 2190727
• DOI: http://doi.org/10.5371/jkhs.2011.23.2.151

Abstract

We report a rare case of a complete disassembly of the inner head from the bipolar cup without polyethylene wear and locking system failure. An 84-year-old man who had a femur neck fracture of the right hip underwent a replacement of the bipolar prosthesis 4 months ago. He fell down from a height of a chair and felt a sudden sharp pain in the right hip. Roentgenograms revealed that the inner head was dislocated from the outer cup; subsequently, a revision surgery was carried out. When the outer head was removed from the acetabulum, the bearing insert and locking ring were not deformed. Because there was no evidence of loosening of the femoral stem, identicallysized bipolar cup and metal head replacement was performed. At a 6 months follow-up, he had mild hip pain but had returned fully to daily living.

Keyword

Bipolar prosthesis; Disassembly; Dislocation; Hemiarthroplasty

MeSH Terms

Acetabulum
Aged, 80 and over
Dislocations
Femoral Neck Fractures
Follow-Up Studies
Head
Hemiarthroplasty
Hip
Humans
Polyethylene
Prostheses and Implants
Ursidae
Polyethylene

Figure

• 

  Fig. 1 The radiograph for patient shows dislocation of the inner head without a detached locking ring and varus position of the outer head.

• 

  Fig. 2 (A) Retrieved bipolar components without any damaged beveled over the outer head and wear of polyethylene insert. (B) A intact locking ring.

• 

  Fig. 3 Postoperative radiograph demonstrates bipolar hemi arthroplasty without revision of the stem.

Reference

1. Hasegawa M, Sudo A, Uchida A. Disassembly of bipolar cup with self-centering system: a report of seven cases. Clin Orthop Relat Res. 2004. 425:163–167.

2. Herzenberg JE, Harrelson JM, Campbell DC 2nd, Lachiewicz PF. Fractures of the polyethylene bearing insert in Bateman bipolar hip prostheses. Clin Orthop Relat Res. 1988. 228:88–93.

3. Holmes JC, Whalen NJ. Disassembly of the osteonics bipolar ring when used with a Howmedica femoral head. A report of four cases. J Arthroplasty. 1992. 7:201–203.

4. Tanaka K, Nakayama Y, Murashige R, et al. A dislocation of the inner head in bipolar prosthesis with a self-centering system: a case report. J Nippon Med Sch. 2002. 69:192–195.

5. Ito H, Matsuno T, Kaneda K. Bipolar hemiarthroplasty for osteonecrosis of the femoral head. A 7- to 18-year followup. Clin Orthop Relat Res. 2000. 374:201–211.

6. Aramaki K, Takeshita M, Ogami T, Hirata O, Iwamoto H. Recurrent dislocation of the inner head in bipolar hip prostheses due to high density polyethylene liner failure; A case report. Sekeigaka Saigaigeka. 1996. 45:4–8.

7. Muramatsu T, Tachibana S, Mikami T, Kawai M, Hirota H, Nakamichi K. Dislocation of the inner head of bipolar hip prosthesis with self centering system; A case report. Seikei Saigaigeka Zasshi. 1994. 37:1403–1407.

8. Lee HH, Lo YC, Lin LC, Wu SS. Disassembly and dislocation of a bipolar hip prosthesis. J Formos Med Assoc. 2008. 107:84–88.

9. Bateman JE. Single-assembly total hip prosthesis-preliminary report. 1974. Clin Orthop Relat Res. 1990. 251:3–6.

10. Phillips TW. The Bateman bipolar femoral head replacement. A fluoroscopic study of movement over a four-year period. J Bone Joint Surg Br. 1987. 69:761–764.