Biomechanical effectiveness of an arthroscopic posterior bankart repair versus an open bone block procedure for posterior shoulder instability.
BACKGROUND
The most effective surgical treatment for traumatic posterior shoulder instability remains unclear.


OBJECTIVE
An arthroscopic posterior Bankart repair is as effective as an open posterior bone block-capsulorrhaphy procedure regarding the restoration of humeral displacement with posterior and inferior forces.


METHODS
Controlled laboratory study.


METHODS
Biomechanical testing of 16 human shoulders was performed in 3 testing conditions: after ventilation (intact joint), after creation of a posteroinferior Bankart lesion with an additional cut of the posterior band of the inferior glenohumeral ligament, and after surgical shoulder stabilization. The shoulder stabilization was performed either by an open posterior bone block procedure and glenoid-based T-capsulorrhaphy or by an arthroscopic Bankart repair. Testing was performed in 2 positions-the sulcus test position and the jerk test position-with a passive humerus load of 50 N applied in the posterior, posteroinferior, and inferior directions.


RESULTS
After the arthroscopic repair, there was no significant difference between the translation and the intact state for all tested directions. The bone block repair-capsulorrhaphy caused a significant decrease of posterior translation (sulcus test and jerk test positions) and posteroinferior translation (jerk test position). But the resulting posterior and posteroinferior translation was even significantly lower than the translation measured for the intact joints. However, the reduction of inferior translation, compared with that of the defect condition, was not significant after the bone block repair (sulcus test and jerk test positions). Compared with that of the intact joint, inferior translation after the bone block repair was significantly higher.


CONCLUSIONS
The posterior bone block repair-capsulorrhaphy overcorrects posterior translation and does not effectively restore inferior stability, whereas the arthroscopic posterior Bankart repair restores posterior and inferior laxity of the intact joint.


CONCLUSIONS
An arthroscopic posterior capsulolabral repair more precisely restores posterior and inferior glenohumeral joint laxity and is therefore recommended as the first choice of treatment.
Department of Orthopaedic Surgery, Hannover Medical School, Germany. wellmann.mathias@web.de
Mathias
M
Wellmann
Evgenij
E
Bobrowitsch
Nicklas
N
Khan
Thilo
T
Patzer
Henning
H
Windhagen
Wolf
W
Petersen
Michael
M
Bohnsack
D000368:Aged; D001182:Arthroscopy / Q000379:methods*; D001696:Biomechanical Phenomena; D002102:Cadaver; D006801:Humans; D007593:Joint Instability / Q000601:surgery*; D008875:Middle Aged; D019637:Orthopedic Procedures / Q000379:methods*; D000070599:Shoulder Injuries; D012785:Shoulder Joint / Q000601:surgery*; D016896:Treatment Outcome