Stabilizing function of coracohumeral ligament

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J. Shoulder Elbow Surg.
Volume 5, Number 2, Part 2
Abstracts S 101
329
STABILIZING FUNCTION OF CORACOHUMERAL LIGAMENT
H. C.
Osu, MD,
*Z. P. Luo, PhD, *S. W. O' Driscol 1, MD, *K. N. An, PhD.
Dept. of Orthopaedics, China Medical College Hospital, Taichung. Tat*an.
*Orthopaedic Biomechanics Laboratory, Mayo CI ini c, Rochester, PIN, O. S. h.
I~elease of coracohumeral ligament (OIL) is sometimes recommended to increase range
of motion during shoulder surgery, and the CHL is kmo*n to thicken the rotator
interval and insert on either side of the bicipital groove to be an important
stabilizer of the biceps tendon. However, the contribution of stabilizing function
of CI]L to glenohumeral joint has not been studied extensively. The purpose of this
study is to investigate the stabilizing function of CHL in different arm
positions.
Six fresh frozen cadaveric shoulders were used. All soft tissues and muscles were
removed exceDt the deltoid, rotator cuff and the long head of biceps, 'which were
loaded through a pulley-cable system along the line of muscle action. The
displacement measurement using a magnetic tracking device was made under an
applied translation load. The displacement ratio (DR) was calculated and normalized
by dividing the length and width of the glenoid. The DR was measured and
statistically compared before and after OIL resection in each testing position.
The stabilizing function of CtlL was ~ost significant in inferior direction and
least in posterior direction, and it was ann-rotation related. The effect of CltL
resection *as most obvious in internat rotation in inferior stability. Mter CtlL
resection was most obvious in internal regained significantly in external rotation
(ER). For anterior stability, the effect of Cite resection was statistically
significant only at greater more anteriorly unstable after CHL resection.
The results revealed that CtlL indeed had stabilizing function in inferior and
anterior directions and it was related to arm rotation. Sacrifice of stabilizing
function in some positions should be kept in mind during surgical release of C[tL.
331
POSTERIOR SHOULDER INSTABILITY: THE RATIONALE FOR
ARTHROSCOPIC TREATMENT
Posterior shoulder instability represents an infrequent,
but often times, a frustrating problem for the orthopaedic
surgeon. Significant advances in our understanding of the
pathomechanics, diagnosis and treatment of this entity
have been made over the past several years.
Recent advances in the understanding of shoulder insta-
bility have lead to the development of arthroscopic recon-
struction techniques for posterior shoulder instability.
The rationale of these techniques are based upon estab-
blished principles for reconstructing the primary re-
straints to posterior translation of the glenohumeral
joint.
Five patients with recurrent posterior shoulder insta-
bility have undergone arthroscopic capsular reconstruction
durlngthe past three years. There were two patients with
reverse
Bankart lesions which were directly repaired to
the posterior glenoid rim. Three patients demonstrated
posterior capsular laxity which were treated by a combina-
tion of capsular plication and a capsular shift procedure.
Postoperatively,
all patients were treated in a brace with
the arm held in neutral rotation. Results of arthroscopic
reconstruction have been favorable in these patients with
four excellent and one fair result (Rowe JBJS 1/78). There
were no operative complications in this series.
330
SHOULDER INSTABILITY IN CASES OF PROGRESSIVE
MUSCULAR DYSTROPHY. Nakamura, R. and Ohotake, S.
Asahikawa, Japan and Aomori, Japan.
There have been few reports about shoulder instability
in cases of progressive muscular dystrophy. We
examined shoulder instability in Duchenne's dystrophy
(DMD) and limbgirdle type dystrophy (L-G) cases.
Materials used in this study were 16 cases of DMD
(all cases were male, aged 11 t o 21years old with a
mean age of 16) and 13 cases of L-G (11 males and 2
females, aged 28 to 50 years old with a mean age of 41).
We measured shoulder instability using X-ray photos
fu several angles.
The shoulder was frequently flail in progressive
inuscular dystrophy. The incidence of descent of the
hun3eral head was 10% or more in 19 of 32 shoulders
(59%) with DMD and l0 of 26 (38%) with L-G.
The value of the transverse glenohumeral index in
the DMD cases was smaller than that of both the L-G
cases and Saha index.
There was a high incidence of abnormal shoulder
instability in both DMD and L-G cases. We feel
weakness of muscle was one of the main causes of
shoulder instability in these cases. In most of DMD
cases, the glenoi d was too small in relation to the
humeral head and this probably was one of the causes
of shoulder instability.
332
Glenoid reconstruction with autogenous lilac
bone graft for a large bony Bankart lesion
Chieh Chiang*, Chian-Her Lee, Leou-Chyr
Lin, Wei-Ming Pal, Man-Kuan Au
*Division of Sports Medicine, Department of
Orthopeadics, Tri-Service General Hospital
Large bony Bankart lesion in recurrent dislocation
of shoulder was not common, articular surface loss
more than 30 % should be reconstructed with bone
block which was recommended by most of authors.
There were two patients who had traumatic
recurrent anterior dislocation of shoulder with large
bony Bankart lesion received glenoid reconstruction
by iliac bone graft. The graft was fixed by two
screws then reattached the anterior capsular
ligament to the graft and let the screws locate
outside of the capsule. The two young male patients
were followed up at least 20 months. The results
showed that there were no pain, no recurrent
dislocation, no limitation of daily activity, but still
had loss of external rotation 5- 10 degrees in
abduction 90 degrees. In conclusion, large Bankart
lesion with articular surface loss more than 30 %
reconstructed with autogenous iliac bone graft
other than direct repair of capsule could get
excellent to good results.