Disassembly of a modular femoral component after femoral head prosthetic replacement.
We report a rare case of a taper-locked femoral inner head that have been completely separated from the stem neck. A 76-year-old man who had hip fracture of the right hip had disassembly of inner head and stem neck after revision of bipolar hip prosthesis. This force could have been amplified by the pumping phenomenon generated after the revised inner head. We suspect the sealed air pushes back the stem neck, and unlocks the taper lock of the inner head, causing separation of the stem neck from the inner head. To prevent pumping phenomenon, we recommend manual testing of the taper lock to confirm that it has been assembled correctly and its integrity before implantation when the bloody and fatty membrane is adequately removed from stem neck.
Department of Orthopaedic Surgery, Nantan General Hospital, Nantan-City, Kyoto, Japan.
Toshiki
T
Shiga
Masaki
M
Mori
Tatsuro
T
Hayashida
Yasuhiro
Y
Fujiwara
Taku
T
Ogura
D000058:Accidental Falls; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019544:Equipment Failure Analysis; D005265:Femoral Neck Fractures / Q000601:surgery*; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012008:Recurrence; D012086:Reoperation