Radiocapitellar joint pressures following transradial amputation increase during elbow motion

Area of Science:

• Orthopedics
• Biomechanics
• Prosthetics

Background:

• Transradial amputation alters upper limb biomechanics.
• The radiocapitellar joint (RCJ) is crucial for elbow function.
• Understanding RCJ pressure changes post-amputation is vital for prosthetic design.

Purpose of the Study:

• To compare RCJ contact area, mean pressure, and peak pressure between normal and transradial amputated upper limbs.
• To investigate the impact of elbow flexion and forearm rotation on RCJ biomechanics after transradial amputation.
• To inform the development of myoelectric prostheses that mitigate joint stress.

Main Methods:

• Utilized ten fresh-frozen upper limb specimens.
• Performed transradial amputation 5 cm proximal to the radial styloid process.
• Employed a custom apparatus and pressure sensors to measure RCJ biomechanical indices during dynamic movements.

Main Results:

• No significant difference in RCJ contact area was observed between groups.
• Mean pressure in the RCJ was consistently higher in amputated limbs across all tested positions.
• Peak pressure was significantly elevated in amputated limbs, especially during pronation at 45° elbow flexion.

Conclusions:

• Elevated mean and peak pressures in the RCJ post-transradial amputation may contribute to cartilage erosion.
• Future myoelectric prosthesis development should prioritize strategies to reduce RCJ pressure.
• Further research into mitigating joint stress in amputees is warranted.