Vibrotactile evaluation: Osseointegrated versus socket-suspended transfemoral prostheses

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Vibrotactile evaluation Osseointegrated versus
socket-suspended transfemoral prostheses

• Eva Häggström, CPO Kerstin Hagberg, PT, PhD
  Björn Rydevik, MD, PhD Rickard Brånemark, MD,
  PhD

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• Aim
• Investigate vibrometric stimuli detection
  thresholds of patients with transfemoral
  amputation with osseointegrated (OI) versus
  socket-suspended prostheses.
• Relevance
• Improved ability to detect vibration at heel
  strike could mean safer walking for this group of
  patients.

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Method

• Subjects
• OI (n 17) Tested preoperatively with
  socket-suspended prostheses and after 2 yr with
  OI prostheses.
• Controls (n 17) Used socket-suspended
  prostheses, evaluated once.
• Prosthetic and intact feet assessed at 8, 16, 32,
  64, 125, and 250 Hz.
• Transmission of vibrometric signals through test
  prosthesis was also measured.

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Results

• OI prosthetic connection improved patients
  ability to detect vibrotactile stimuli of higher
  frequencies applied under prosthetic foot.
• At 2 yr follow-up
• OI group showed lower detection threshold at 125
  Hz than in preoperative measurement.
• OI group had lower detection threshold than
  controls at both 125 and 250 Hz.

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Conclusion

• Study provides insight into mechanisms of
  vibration transmission between exterior and
  bone-anchored as well as socket-suspended
  amputation prostheses.
• Improved osseoperception might explain why
  patients with OI prostheses have described
  prosthesis as feeling like a a part of them.
• Results add to published benefits of OI
  prostheses.