Acromio-clavicular separation masked by muscle spasm

Area of Science:

• Orthopedics
• Radiology
• Sports Medicine

Background:

• Acromio-clavicular (AC) separation diagnosis often relies on weight-bearing X-rays.
• Muscle spasms (deltoid and trapezius) can falsely indicate joint stability.
• Accurate imaging is crucial for appropriate treatment of AC joint injuries.

Purpose of the Study:

• To evaluate methods for improving the diagnostic accuracy of weight-bearing X-rays in suspected acromio-clavicular separations.
• To address the confounding effect of muscle spasm on radiographic assessment.
• To propose a follow-up imaging strategy when initial stress views are inconclusive.

Main Methods:

• Review of diagnostic challenges in acromio-clavicular separation.
• Analysis of the impact of muscle spasm on radiographic interpretation.
• Discussion of modified weight-bearing techniques (strapped weights).
• Consideration of local anesthetic infiltration for diagnostic clarification.

Main Results:

• Extensive deltoid and trapezius muscle spasm can create misleading weight-bearing X-ray findings.
• Strapping weights to the wrist, instead of hand-held, may reduce the effect of muscle spasm.
• When clinical suspicion is high but stress films are negative, repeat imaging after local anesthetic infiltration is recommended.

Conclusions:

• Muscle spasm is a significant confounder in diagnosing acromio-clavicular separation with weight-bearing views.
• Modifications to weight-bearing techniques and the use of local anesthetics can enhance diagnostic reliability.
• A stepwise approach involving modified imaging and anesthetic infiltration improves diagnostic confidence for AC joint injuries.