A reduction in the amount of arm
external rotation at stride foot contact was associated with a reduction is stressful kinetics at the elbow (Fleisig 1994).
There was positive correlation seen in the athletes group between the thoracohumeral angles and scapular spinal tilt rotation at the extreme position of shoulder
external rotation.
Consequently, greater
external rotation is required for engagement of the Hill-Sachs lesion.
46 Table 5 Shoulder Range of Motion and Strength Based on Player Position; Defensemen Have a Statistically Significant Increase in
External Rotation with the Arm at the Side for the Left Shoulder and a Trend toward Increased
External Rotation with the Arm at the Side for the Right Shoulder Range of Motion (degrees) FE ER90 IR90 ER0 Forwards Right Shoulder 176 95 64 56 Defensemen Right Shoulder 176 92 69 65 P value 0.
Combined latissimus dorsi and teres major tendon transfers for
external rotation deficiency in reverse shoulder arthroplasty.
Tibial
external rotation increased with knee extension for both groups, but there was no significant difference between the groups at any flexion angles (Figure 4).
As described in Table 3, rTSA patients were observed to have significantly larger improvements in outcome as measured by two of the five metrics (UCLA and Constant), significantly larger improvements in active forward flexion and strength, and significantly less improvements in active
external rotation and in the active internal rotation score than the improvements associated with aTSA patients.
The arguments against subscapularis repair in a lateralized rTSA prosthesis are improved
external rotation mechanics (30) and abduction efficiency, (13,23,24,30) both of which have been identified as problems following rTSA and which repairing the subscapularis has been shown to worsen.
Muscle transfers are often recommended in reverse shoulder patients with
external rotation deficiency because the posterior deltoid alone is insufficient to restore active
external rotation.
Thus, a direct posterior offset of the humerus would be expected to increase the
external rotation torque of the posterior rotator cuff.
One outcome commonly reported with reverse shoulders is poor
external rotation strength and range of motion.
13-15) Iannotti and Norris (13) found that, compared to other patients with shoulder arthroplasty in their study, patients with posterior subluxation of the humeral head and posterior glenoid erosion had lower final American Shoulder and Elbow Surgeons scores, increased pain, and decreased active
external rotation.
