Para-labral Cyst of Shoulder

Shoulder pain in young active individuals and athletes can arise from a variety of causes. One lesser-known but clinically important condition is the paralabral cyst. 

Although relatively uncommon, this condition can lead to persistent shoulder pain, weakness, and nerve compression if left untreated. 

Understanding the condition helps patients seek timely treatment and prevent long-term shoulder dysfunction.

What is a para-labral cyst?

Generally, cyst is a fluid-filled sac that can be found at various locations in human body. 

Paralabral cyst of Shoulder (blue balloon like)

A paralabral cyst is the one that forms adjacent to the shoulder socket (glenoid) and its rubber-like boundary (labrum). The labrum deepens the socket, helping stabilise the ball-and-socket joint.

These cysts may remain small and asymptomatic, but in some cases they grow large enough to compress nearby nerves and cause significant pain and weakness.

Why do para-labral cysts develop in shoulder?

The main underlying cause of a paralabral cyst is a tear in the labrum (boundary of shoulder socket). Once the labrum is damaged, joint fluid escapes through the tear and forms a one-way valve mechanism. Fluid accumulates outside the joint and gradually enlarges into a cyst.

Common risk factors include:

1. Repetitive overhead activities:

Athletes involved in sports such as tennis, volleyball, badminton, and cricket bowling frequently place stress on the shoulder joint. Repetitive overhead motion can gradually damage the labrum.

2. Shoulder injury:

A fall on an outstretched arm, shoulder dislocation, or sudden traction injury can cause a labral tear, which later leads to cyst formation.

3. Shoulder instability:

Repeated episodes of shoulder subluxation or instability can predispose the labrum to an injury.

4. Degenerative changes:

In middle-aged individuals, degenerative wear and tear of the labrum may also contribute to a cyst formation.

Where exactly is the para-labral cyst located?

Paralabral cysts can develop in different parts of the shoulder depending on the location of the labral tear.

The common sites include:

1. Posterior:

These cysts are most common and notorious. On significant enlargement, they compress the suprascapular nerve, which supplies two important muscles of rotator cuff, viz supraspinatus and infraspinatus. Nerve compression  eventually leads to weakness and wasting of these muscles.

2. Anterior:

They are less common and associated with shoulder instability (dislocations or subluxations).

3. Inferior:

These are the rarest but may occur in cases of severe traumatic injuries such as road traffic accidents.

When to suspect a para-labral cyst?

The symptoms depend largely on the size, location of the cyst and whether it compresses nearby nerves.

Common symptoms include:

1. Pain: Dull or deep pain in the shoulder is the most frequent complaint. Pain may worsen during overhead activities or lifting.

2. Weakness: If the cyst compresses the suprascapular nerve, patients may experience weakness in certain shoulder movements. Loss of shoulder strength without any recent trauma points towards the nerve pathology.

3. Reduced athletic performance: Athletes may notice loss of strength or endurance, particularly in overhead sports.

4. Limited range of motion: Some patients may develop stiffness or restriction of shoulder movements.

5. Muscle wasting: In chronic cases with nerve compression, wasting of rotator cuff muscles (infraspinatus) may occur.

Wasting of infraspinatus muscle

Interestingly, some paralabral cysts may remain completely asymptomatic and are discovered incidentally during imaging.

How is it diagnosed?

Diagnosing a shoulder paralabral cyst requires a combination of clinical evaluation and imaging studies.

1. Clinical Examination

During a physical examination, an orthopaedic surgeon evaluates:

• Shoulder movements (range of motion)

• Muscle strength

• Signs of labral injury

• Tests for nerve involvement

Patients with suprascapular nerve compression wasting of infraspinatus muscle over the shoulder blade (scapula) and show weakness in external rotation of the shoulder.

2. MRI scan

The most reliable investigation for diagnosing paralabral cysts is Magnetic Resonance Imaging (MRI). it clearly demonstrates:

MRI showing the cyst (white)

• Details of the cyst: origin, size, extent, contents

• Associated labral tear

• Nerve compression

• Muscle atrophy if present

MRI arthrography may provide even better visualisation of labral pathology, but is rarely required.

3. Ultrasound

In some cases, ultrasound may detect superficial cysts, though it is less accurate than MRI for evaluating labral tears.

What is the treatment?

The treatment strategy depends on the severity of symptoms, size of the cyst and presence of nerve compression.

A) Non-Surgical Treatment:

Small cysts without nerve involvement are initially treated conservatively.

1. Activity Modification: Patients are advised to avoid activities that aggravate shoulder pain, such as repetitive overhead movements.

2. Physiotherapy: Strengthening exercises for the rotator cuff and scapular stabilisers can help improve shoulder function.

3. Anti-inflammatory Medications: They help to control the inflammation and pain to certain extent early in the disease.

B) Surgical Treatment:

Surgery is advised in patients with 

• persistent pain, not responding to conservative treatment

• nerve compression causing weakness.

This can be very well handled by minimally invasive key-hole surgery called ‘arthroscopy’.

> Arthroscopic Cyst Decompression  and Labral Repair:

Schematic representation of torn labrum being repaired arthroscopically

• Addresses both the cause i.e. the torn labrum and its effect i.e the cyst

• Cyst decompression relieves the pain and the pressure over suprascapular nerve

• Labral repair seals the defect through which the joint fluid escapes, preventing any future recurrence. It also takes care of any joint instability.

• Being minimally invasive, it allows faster recovery compared to an open surgery with less chances of infection.

  
  

Recovery After Surgery

Recovery following arthroscopic treatment occurs in stages.

1. Immobilisation Phase (first 4 weeks):

Shoulder is supported in a sling to protect the repair and allowing it to heal.

2. Rehabilitation Phase (4 to 12 weeks):

Gradual physiotherapy is started to restore range of motion and strength.

3. Return to Sports (3 to 6 months):

Athletes can gradually resume sports after adequate strength and stability are achieved.

Most patients experience excellent pain relief and restoration of shoulder function.

What happens if the cyst is not treated on time?

If left untreated, a paralabral cyst can lead to following complications:

• Persistent shoulder pain

• Suprascapular nerve compression

• Infraspinatus muscle atrophy (reversible)

• Fatty degeneration of the muscle belly, which can lead to permanent weakness (irreversible)

Early diagnosis and treatment significantly reduce the risk of long-term complications.

Can the cyst be prevented from being formed altogether?

While not all paralabral cysts can be prevented, certain measures can reduce the risk of labral injuries:

• Proper training techniques in overhead sports

• Adequate shoulder strengthening exercises

• Avoiding overuse injuries

• Early evaluation of persistent shoulder pain

Athletes should seek medical advice if shoulder pain persists for more than a few weeks or if weakness develops.

Take home.. 

In case of persistent shoulder pain or weakness, consult an orthopaedic specialist at the earliest. It will help identify the underlying problem and get the appropriate treatment on time.

Paralabral cyst, although sounds simple, can cause long term complications. In patients not responding to conservative treatment, arthroscopic surgery is quite rewarding and restores complete shoulder function.

If you are suffering from similar symptoms, get an expert opinion from Dr.Ajinkya Achalare at ArthroSports Speciality Orthopaedic Clinic at Dadar, Mumbai.