One High-Volume Posteromedial Knee Capsular Injection Can Provide Safe Anesthetic Infiltration Across the Entire...

Area of Science:

• Orthopedic Surgery
• Anesthesiology
• Anatomy

Background:

• Posterior knee analgesia is crucial for post-operative pain management.
• Injections into the central or posterolateral knee capsule risk neurovascular injury.
• Evaluating alternative injection techniques is necessary to improve safety and efficacy.

Purpose of the Study:

• To compare the distribution of a single posteromedial injection versus a dual posteromedial and posterolateral injection of anesthetic.
• To assess the safety and effectiveness of a single-injection technique for posterior knee analgesia.

Main Methods:

• Fresh cadaveric knees were used for the study.
• A single injection of 50 ml contrast was administered posteromedially in four knees.
• A dual injection technique (12.5 ml each) was performed posteromedially and posterolaterally in four other knees.
• Computed tomography scans evaluated contrast distribution after joint manipulation.

Main Results:

• Both techniques showed extensive posterior fluid distribution.
• The single posteromedial injection covered an average of 80% of the capsular width within 5 mm of the injection site.
• The dual-injection technique covered an average of 63%.

Conclusions:

• A single 50 mL injection into the posteromedial knee capsule achieves comprehensive anesthetic distribution.
• This method effectively anesthetizes the posterior knee without endangering critical neurovascular structures.
• The single posteromedial injection technique is a preferred, safer alternative for posterior knee analgesia.