Arthroscopic classification of posterior labrum glenoid insertion

Area of Science:

• Orthopedic Surgery
• Anatomy
• Radiology

Background:

• The posterior labrum's glenoid insertion is crucial for shoulder stability.
• Variability in this insertion can lead to diagnostic challenges and misinterpretations of pathology.

Purpose of the Study:

• To prospectively investigate and classify the variability of the posterior labrum's glenoid insertion using arthroscopy.
• To determine if pre-operative arthro-CT scans can accurately identify these variations.

Main Methods:

• Prospective arthroscopic evaluation of 86 patients' posterior labrum glenoid insertions (superior, medial, inferior segments).
• Classification of insertions into normal, medialized, torn, or absent categories.
• Correlation of arthroscopic findings with pre-operative arthro-CT scans in 56 shoulders.

Main Results:

• Four types of posterior labrum insertions were identified, with normal insertion (Type 1) in 60% of cases.
• Medialized insertions were observed in superior (20%), superior and medial (15%), and all posterior segments.
• Arthro-CT demonstrated variable sensitivity and specificity in identifying medialized insertions across different segments.

Conclusions:

• Significant variability exists in posterior labrum glenoid insertions.
• This variability poses a risk for misdiagnosing posterior labral tears, particularly in cases of posterior instability.
• Non-pathological variations may be incorrectly identified as labral lesions.