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Kinematics of the glenohumeral joint with bankart lesion and repair
Author(s) -
Novotny John E.,
Nichols Claude E.,
Beyn Bruce D.
Publication year - 1998
Publication title -
journal of orthopaedic research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.041
H-Index - 155
eISSN - 1554-527X
pISSN - 0736-0266
DOI - 10.1002/jor.1100160120
Subject(s) - bankart lesion , kinematics , lesion , joint (building) , bankart repair , orthodontics , medicine , computer science , surgery , engineering , orthopedic surgery , physics , structural engineering , classical mechanics
A Bankart repair is performed to reduce abnormal translations of the humeral head on the glenoid due to a Bankart lesion, a separation of the capsulolabral complex from the glenoid rim. However, this is often accompanied by a loss of rotational range of motion that may lead to decreased function and osteoarthritis. This loss of rotation, coupled to the goal of reducing humeral translations, may be a result of the amount of imbrication of the capsule during repair. To determine the effects of capsular imbrication, we investigated how two Bankart repairs (2.5 and 5.0 mm of capsular imbrication) and a Bankart lesion altered the translations and rotations of the human glenohumeral joint in vitro . Coupled moments were applied to the unconstrained humerus in abduction‐adduction, in flexion‐extension, and to simulate the cocked phase of throwing. Motion was measured with an electromagnetic system. There were no differences in the kinematics betweenthe intact specimens and those with a Bankart lesion or between normal specimens and the first (2.5 mm) Bankart repair. The first repair significantly reduced external rotation for the cocked phase of throwing compared with the Bankart lesion: from 46.8 ± 23.6° to 32.4 ± 14.2° (±SD). The second (5.0 mm) Bankart repair produced significantly different posterior translation (‐4.7 ± 3.9 mm) of the humeral head relative to the glenoid compared with normal (5.1 ± 4.7 mm anterior) and the first repair (6.1 ± 8.3 mm anterior), as the humerus moved from full flexion to full extension. Differences were also found for all rotations in the cocked phase of throwing. For the second repair, the humerus extended 24.3° and externally rotated 18.6° less than normal and was abducted 15.4° more. These results indicate that both Bankart repairs do little to affect humeral translations with unconstrained moment loading but that rotations are affected during the cocked phase of throwing, with significant losses of external and extension rotations.