JOURNAL ARTICLE

Biomechanical assessment of Type II superior labral anterior-posterior (SLAP) lesions associated with anterior shoulder capsular laxity as seen in throwers: a cadaveric study

Teruhisa Mihata, Michelle H McGarry, James E Tibone, Michael J Fitzpatrick, Mitsuo Kinoshita, Thay Q Lee
American Journal of Sports Medicine 2008, 36 (8): 1604-10
18359822

BACKGROUND: Type II superior labral anterior-posterior lesions in throwers are often associated with anterior shoulder capsular laxity.

HYPOTHESIS: Shoulder instability in patients with type II superior labral anterior-posterior lesions may result from the associated shoulder capsular laxity rather than the superior labral anterior-posterior lesion alone.

STUDY DESIGN: Controlled laboratory study.

METHODS: Six cadaveric shoulders were externally rotated to 20% beyond the maximum humeral external rotation at 60 degrees of glenohumeral abduction, which simulated 90 degrees of shoulder abduction, to detach the superior labrum and elongate the anterior shoulder capsular ligaments. The detached labrum was then repaired to isolate the effect of the detached superior labrum and that of the capsular laxity. Rotational range of motion was measured at 60 degrees of glenohumeral abduction. Anterior-posterior glenohumeral translation was measured at 30 degrees and 60 degrees of glenohumeral abduction. Superior-inferior glenohumeral translation was measured at 0 degrees and 60 degrees of glenohumeral abduction.

RESULTS: The experimentally created type II superior labral anterior-posterior lesion and capsular laxity significantly increased anterior translation at 30 degrees (mean difference, 1.0 +/- 0.8 mm; P < .05) and 60 degrees (mean difference, 2.2 +/- 2.0 mm; P < .05) of glenohumeral abduction. Subsequent superior labral anterior-posterior repair restored the anterior translation but only at 30 degrees of glenohumeral abduction (mean difference, 0.9 +/- 0.6 mm; P < .05).

CONCLUSION: Because of the anterior capsular laxity associated with type II superior labral anterior-posterior lesions, superior labral anterior-posterior repair of the peeled-back superior labrum may not restore anterior glenohumeral translation at 90 degrees of shoulder abduction.

CLINICAL RELEVANCE: Anterior shoulder capsular laxity associated with type II superior labral anterior-posterior lesions may cause anterior shoulder instability at 90 degrees of shoulder abduction in throwers even after superior labral anterior-posterior lesion repair.

Full Text Links

Find Full Text Links for this Article

Discussion

You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read
18359822
×

Save your favorite articles in one place with a free QxMD account.

×

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"