Glenoid Paralabral Cysts Causing Shoulder Pain and Isolated Infraspinatus Weakness: Early Arthroscopic Decompression and Labral Repair Leads to Complete Recovery: A Case Series

Abstract

Introduction: Shoulder pain in young patients can be caused by various conditions such as tendinitis, bursitis, capsulitis, and labral tears. Superior labrum anterior to posterior (SLAP) tears can sometimes be associated with a paralabral cyst, which can compress the suprascapular nerve and cause isolated weakness of the infraspinatus muscle and present as shoulder pain. A detailed examination and proper investigation can help in early diagnosis of such cases. Arthroscopic decompression and SLAP repair lead to complete recovery and excellent outcomes in such patients.

Cases report: We had four young patients who presented to our clinic with a history of shoulder pain and difficulty performing overhead activities. Upon examination, all four exhibited painful active shoulder range of motion and isolated infraspinatus muscle weakness. Magnetic resonance imaging (MRI) was obtained as part of a routine investigation, revealing SLAP tears with paralabral glenoid cysts compressing the suprascapular nerve at the spinoglenoid notch. MRI also indicated signs of denervation in the infraspinatus muscle in all patients. All patients underwent arthroscopic labral repair with intra-articular decompression of the paralabral cyst. Post-surgery rehabilitation commenced with simple pendulum exercises, followed by periscapular and rotator cuff strengthening exercises. All four patients showed excellent recovery at follow-up, with painless active shoulder range of motion and regained full power of the infraspinatus muscle with return to sports by 6 months.

Conclusion: Labral tears associated with paralabral cysts can present with isolated infraspinatus weakness due to suprascapular nerve compression at the spinoglenoid notch. A high index of suspicion and thorough clinical examination are required to identify these patients. Early detection and treatment with intra-articular cyst decompression with labral repair followed by a thorough rehabilitation program led to complete recovery in these cases.

Keywords: Labral tear; compression; decompression; infraspinatus; intra-articular; notch; paralabral cyst; spinoglenoid; weakness.

Figure 1

(A) PDFS coronal image showing type-II superior labrum anterior to posterior tear (orange arrow) with paralabral cyst in the spinoglenoid notch (white arrow). (B) PDFS sagittal image showing hyperintensity in the infraspinatus and teres minor muscle.

Figure 2

Superior labrum anterior to posterior tear with large paralabral cyst, denervation edema in infraspinatus.

Figure 3

(A) Posterosuperior labral tear showing continuity with the para labral cyst. (B) denervation edema in the infraspinatus muscle with mass effect of the cyst. (C] Type II superior labrum anterior to posterior tear with cyst in the spinoglenoid notch.

Figure 4

(A) PDFS sagittal image showing multiloculated paralabral cyst causing compression of the suprascapular nerve. (B) labral tear extending from 11 to 9 o’clock position (black arrow) with denervation edema in the infraspinatus muscle (pink arrow).

Figure 5

(Left) accessing cyst through the labral tear (middle) decompression of the cyst draining pale yellow cyst fluid (right) labral repair using knotless suture anchor after decompression.