Muscle Healing in Sports Injuries: MRI Findings and Proposed Classification Based on a Single Institutional...

Area of Science:

• Musculoskeletal Imaging
• Sports Medicine
• Radiology

Background:

• Muscle injuries are common in athletes, with healing progressing through distinct pathophysiologic and histologic phases.
• While the stages of muscle healing are understood, detailed MRI findings for each phase have not been fully described.

Purpose of the Study:

• To review MRI findings in muscle healing and propose a practical imaging classification.
• To correlate MRI findings with histologic changes in muscle tears.

Main Methods:

• Analysis of 310 MRI studies (basal and follow-up) in 128 athletes with muscle tears.
• Correlation of MRI findings with clinical evolution and histologic changes.
• Proposal of a classification based on morphology and signal intensity.

Main Results:

• A three-phase classification (destruction, repair, remodeling) based on MRI findings is proposed.
• Destruction phase: myoconnective tissue discontinuity, featherlike edema.
• Repair phase: immature scar fills gaps.
• Remodeling phase: scar maturation, edema regression.
• Healed stage: slight fusiform connective tissue thickening.
• Specific warning signs like persistent edema and scar rupture are identified.

Conclusions:

• MRI findings can be classified into distinct phases corresponding to muscle healing stages.
• A truncated MRI protocol with a 3-T magnet can provide essential information.
• Understanding MRI signs of healing and warning signs optimizes athlete return to play.