Loss of Joint Position Awareness May Impede Return to Overhead Sports After Injury
References: Int J Sports Med 2006;27:648-652.
Surgeons can restore shoulder stability of injured overhead athletes, but subsequent lack of joint position awareness prevents a substantial proportion of them from returning to their previous performance level, investigators in Germany report.
Overhead activities, such throwing, tennis and volleyball, are associated with injuries leading to anterior shoulder instability. Dr. Reinhard W. Fremerey, from Klinikum Hildesheim, and colleagues advise that patients be cautioned that corrective surgery will help, but may not lead to restored sports activity.
In their study, 22 overhead athletes with posttraumatic, unidirectional anterior shoulder instability underwent an anterior capsulolabral reconstruction. After a mean follow-up of 2.8 years, the investigators compared the group with 20 overhead athletes who had no history of shoulder pain or injury.
Nineteen patients (86%) were free of pain, while three reported exercise-dependent pain. Subject satisfaction, as measured with a visual analog scale, was high (mean 8.1 points).
Despite these good outcomes, only 12 (55%) patients returned to their prior levels of sport activities, the investigators report in the August issue of the International Journal of Sports Medicine.
Joint position awareness was evaluated using a passive angle reproduction test. In the control group, there was no significant difference between perceived and target angles.
In the patient group, neutral position and external rotation seemed to be unaffected. However, a persistent deficit in the internal rotation position was observed (p < 0.05).
Twelve patients regained joint position awareness, 9 of whom returned to their previous sports activity level. In contrast, the presurgical activity level was restored in only 3 of 10 patients lacking joint position awareness.
According to Dr. Fremerey's group, "A sufficient biomechanical/ligamentous reconstruction of the joint structure does not reliably guarantee a full recovery of the joint function," which they blame on "a disturbance in the neuromuscular interactions."
They also suggest that the deficit in joint position awareness could be caused by "reduced stretching of the anterior capsular ligament complex, with a corresponding reduction of the intracapsular mechanoreceptor's activity in internal rotation."
They recommend shoulder rehabilitation programs be developed to restore joint position awareness along with power and movement.