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Modular ulnar head decoupling force: case report
1REMI Sciences Inc., Pinnacle Health Hand Center, Mechanicsburg, PA, USA. Snaidu3555@comcast.net
The Journal of Hand Surgery
|May 19, 2009
Summary
Revision surgery for dislocated cobalt-chrome ulnar head implants presents a significant challenge. The Morse-taper disassembly force is substantial, requiring considerable force to overcome during these procedures.
Area of Science:
- Orthopedic Surgery
- Biomedical Engineering
- Materials Science
Background:
- Cobalt-chrome modular distal ulnar head arthroplasty restores stability to the distal radioulnar joint.
- Revision of dislocated implants can be intraoperatively challenging.
- Disassembly force data for these implants is not widely published.
Observation:
- A case involving significant difficulty during revision of a dislocated modular cobalt-chrome distal ulnar head implant is presented.
- The Morse-taper disassembly force of the retrieved implant was measured.
- The force required was 2958 N +/- 1272.
Findings:
- The mean Morse-taper disassembly force for the retrieved implant was 2958 N +/- 1272.
- This force is approximately 4.5 times the average body weight.
- The disassembly strength of the modular ulnar head presents a formidable intraoperative challenge.
Implications:
- Understanding the Morse-taper disassembly force is crucial for surgeons performing revision arthroplasty.
- This data highlights the need for specialized techniques or tools to manage difficult disassemblies.
- Further research into implant design and revision strategies may be warranted.
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