More Information on Rotator Cuff Surgery.
Last updated Wednesday, January 26, 2005
Figure 4 - Position of fusion Arthrodesis
When a massive cuff defect coexists with a detached, denervated, or
dysfunctional deltoid, the shoulder is without effective glenohumeral
motors.Salvage option Under these circumstances, a glenohumeral arthrodesis provides a
salvage option. By securing the humeral head to the scapula, the
scapular motors can be used to power the humerus through a very limited
range of humerothoracic motion. We prefer a fusion technique which
preserves all remaining deltoid function, and which uses decortication
of the humerus and glenoid, 6.5 mm compression screws across the joint,
with or without a neutralization plate from the scapular spine across
the joint and down the humeral shaft.
The best candidates for this procedure are those patients with:
- permanent and severe weakness due to loss of cuff and deltoid function;
- a good understanding of the limitations and potential complications of a shoulder fusion;
- intact scapular motors;
- good motivation; and
- minimal complaints of pain.
To establish the limitations of shoulder fusions, we studied the
humerothoracic motion of twelve patients who had glenohumeral
arthrodeses at least two years prior to the time of study. Elevation in
the plus 90 degrees (anterior sagittal) plane averaged 47 degrees.
Elevation in the minus 90 degrees (posterior sagittal) plane averaged
22 degrees. External rotation averaged 9 degrees and internal rotation
46 degrees. These ranges of motion were similar to the scapulothoracic
motion measured in normal subjects. Only one of the patients could
reach his hair without bending his neck forward, only five could reach
their perineum, six could reach the back pocket, seven the opposite
axilla, and ten the side pocket.
We studied normal in vivo shoulder kinematics to predict the
functions which would be allowed by various positions of glenohumeral
arthrodesis, assuming that the scapulothoracic motion would remain
unchanged. Using the normal scapulothoracic motions we were able to
model the functional effects of fusion positions (reported in relation
to the thorax). We found that activities of daily living could be best
performed if the joint was fused in 15 degrees of flexion, 15 degrees
of abduction, and 45 degrees of internal rotation. This position of
fusion with a low angle of elevation and relatively high degree of
internal rotation facilitated reaching the face, opposite axilla, and
perineum (see figure). However, all positions represented major
compromises of normal function.
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