Fatigue characteristics following ankle fractures

Area of Science:

• Orthopedics
• Sports Medicine
• Rehabilitation Science

Background:

• Ankle fractures often lead to prolonged immobilization, potentially affecting muscle function.
• The long-term consequences of surgical versus nonsurgical treatment on muscle contractile properties remain incompletely understood.

Purpose of the Study:

• To investigate the effects of surgical (internal fixation) and nonsurgical management of immobilized ankle fractures on muscle function.
• To compare voluntary and evoked contractile properties before and after a fatigue protocol in fracture and control groups.

Main Methods:

• Assessed plantar flexor voluntary and evoked contractile properties in 12 control and 24 previously immobilized ankle fracture subjects (internally fixated and nonfixated).
• Utilized an isometric, intermittent, submaximal fatigue protocol.
• Measured force output, muscle activation (EMG), M-waves, and twitch torques before and after fatigue.

Main Results:

• Fracture groups exhibited lower pre-fatigue force output and muscle activation compared to controls.
• All groups showed similar relative decreases in force and activation post-fatigue.
• Internally fixated subjects performed fewer contractions, showed increased EMG activity, and experienced greater fatigability than nonfixated and control groups.

Conclusions:

• Internal fixation for ankle fractures may lead to increased muscle fatigability, potentially due to intrinsic muscle factors rather than impaired neuromuscular propagation.
• Nonsurgical management allowed for fatigue resistance comparable to controls, suggesting preserved neuromuscular function.
• Further research into the intrinsic properties of muscles following different ankle fracture treatments is warranted.