Arthrogenic Muscle Inhibition Following Knee Injury or Surgery: Pathophysiology, Classification, and Treatment.

Area of Science:

• Orthopedics
• Neurology
• Sports Medicine

Background:

• Arthrogenic muscle inhibition (AMI) is neural inhibition causing quadriceps activation failure post-knee injury or surgery.
• Current classifications do not address the varied presentations of AMI following knee injury.
• AMI can lead to significant morbidity, necessitating early recognition and tailored treatment.

Purpose of the Study:

• To propose a novel classification system for arthrogenic muscle inhibition (AMI) following knee injury or surgery.
• To define distinct presentations of AMI to guide clinical management.
• To improve patient outcomes by addressing the specific needs associated with different AMI classifications.

Main Methods:

• The study proposes a classification system based on the presentation of vastus medialis obliquus (VMO) inhibition and extension deficits.
• The classification includes grades for VMO contraction, hamstring contracture involvement, and chronicity of extension deficits.
• Treatment responsiveness is considered within the classification to differentiate management pathways.

Main Results:

• A grading system (Grade 0 to 3) is proposed to categorize AMI presentations.
• Grade 1 involves VMO inhibition, with subgrades for reversibility (1a) or need for specific programs (1b).
• Grade 2 includes extension deficits with VMO inhibition, with subgrades for reversibility (2a) or refractory cases (2b); Grade 3 is chronic and irreducible.

Conclusions:

• A new classification for arthrogenic muscle inhibition (AMI) is proposed to address variable presentations after knee injury.
• This classification aids in identifying patients at risk for postoperative complications like stiffness.
• Implementing this system can guide therapeutic interventions and improve rehabilitation strategies for AMI.