HOME HELP CONTACT US SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:
Sign In to gain access to subscriptions and/or personal tools.

This Article Full Text Full Text (PDF) All Versions of this Article: 36/4/767    most recent 0363546507312169v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Request Reprints Google Scholar Articles by Youm, T. Articles by Lee, T. Q. PubMed PubMed Citation Articles by Youm, T. Articles by Lee, T. Q. Related Collections Biomechanics Kinematics and kinetics Shoulder

Simulated Type II Superior Labral Anterior Posterior Lesions Do Not Alter the Path of Glenohumeral Articulation

A Cadaveric Biomechanical Study

Thomas Youm, MD^,*, James E. Tibone, MD, Neal S. ElAttrache, MD, Michelle H. McGarry, MS^,|| and Thay Q. Lee, PhD^,||

From Kerlan-Jobe Orthopaedic Clinic, Los Angeles, California, Department of Orthopaedic Surgery, Keck School of Medicine, University of Southern California University Hospital, Los Angeles, California, Orthopaedic Biomechanics Laboratory, VA Healthcare System, Long Beach, California, and ^|| University of California, Irvine, Irvine, California

^* Address correspondence to Thomas Youm, MD, 1056 Fifth Avenue, New York, NY 10028 (e-mail: youmt01{at}yahoo.com).

Background: Previous studies have demonstrated increased glenohumeral translations with simulated type II superior labral anterior posterior lesions, which may explain the sensation of instability in the overhead-throwing athlete. It is unknown whether this amount of increased translation alters glenohumeral kinematics.

Purpose: To determine whether type II superior labral anterior posterior lesions significantly alter glenohumeral kinematics as defined by path of glenohumeral articulation in a simulated cadaveric model of the throwing shoulder.

Study Design: Controlled laboratory study.

Methods: Six cadaveric shoulders were tested for glenohumeral rotational range of motion and translation using a custom shoulder testing system and the Microscribe 3DLX. The path of glenohumeral articulation was measured by calculating the humeral head center with respect to the glenoid articular surface at maximal internal rotation, 30°, 60°, 90°, and maximal external rotation. Data were recorded for vented intact shoulders, shoulders with arthroscopically created type II superior labral anterior posterior lesions, and shoulders with arthroscopically repaired superior labral anterior posterior lesions.

Results: A subtle but significant increase in external rotation (2.7°) was seen after creating a type II lesion. Small increases in glenohumeral translation were found in the anterior (0.9 mm) and inferior (0.9 mm) directions with application of a 15-N force in the superior labral anterior posterior group. Increases in glenohumeral rotation and translation were restored to the intact state after repair of the lesion. No significant differences were found in the path of glenohumeral articulation for the superior labral anterior posterior condition compared with the intact shoulder.

Conclusion: The small amounts of increased external rotation and translation found with arthroscopically created type II superior labral anterior posterior lesions do not significantly affect glenohumeral kinematics in this passive motion model as quantified by the path of glenohumeral articulation.

Clinical Relevance: Findings suggest that in the absence of pain or mechanical symptoms, type II superior labral anterior posterior lesions that do not significantly involve the superior and middle glenohumeral ligaments may not need surgical repair.

Key Words: superior labral anterior posterior (SLAP) lesion • kinematics • shoulder • biomechanics