What is Quadrilateral Space Syndrome (QSS)?

Quadrilateral Space Syndrome (QSS) is a rare condition that occurs when the axillary nerve and/or the posterior circumflex humeral artery get squeezed or compressed as they pass through a small area in the back of your shoulder called the 'quadrilateral space.' This compression can lead to pain, numbness, tingling, and weakness in your arm.

QSS is often caused by repetitive overhead activities, common in athletes like throwers, swimmers, and tennis players. It can also result from repeated motions that narrow the space (overuse), extra bands of tissue that can form and compress the nerve or artery (fibrous bands), trauma or injury such as a shoulder dislocation or a direct blow to the shoulder which can cause swelling or scar tissue, or muscle enlargement if muscles in the area grow significantly (e.g., in bodybuilders), they can crowd the space.

What are the common symptoms of QSS?

Symptoms typically include vague pain or a dull ache in the back of the shoulder, sometimes radiating down the arm; numbness, tingling, or a 'pins and needles' sensation in the shoulder and upper arm; pain that worsens with overhead movements or when your arm is in a 'throwing' position; tenderness when pressure is applied over the back of the shoulder in the quadrilateral space; weakness or fatigue in the arm, especially when lifting or rotating it; and sometimes, shrinking (atrophy) of certain shoulder muscles like the teres minor or deltoid.

How is QSS diagnosed?

Diagnosing QSS can be challenging because its symptoms can be similar to other shoulder problems. Your doctor will ask about your symptoms, activities, and any past injuries; perform a physical examination to check your shoulder's range of motion, strength, sensation, and tenderness; may order imaging tests like MRI or ultrasound to look at the quadrilateral space, assess muscle size, and check for any abnormalities or scarring. In some cases, nerve conduction studies (NCS) or electromyography (EMG) might be performed to evaluate how well the axillary nerve is working. An injection of local anesthetic into the quadrilateral space that temporarily relieves your symptoms can also help confirm the diagnosis.

What are the non-surgical treatment options?

Most cases of QSS improve with non-surgical treatment. These options focus on reducing pressure on the nerve and artery, managing pain, and restoring function: rest and activity modification (avoiding or modifying activities that worsen your symptoms, especially overhead movements); anti-inflammatory medications (over-the-counter or prescription NSAIDs like ibuprofen can help reduce pain and inflammation); ice or heat packs (applying ice can help reduce pain and inflammation, especially after activity, heat can help relax muscles); physical therapy (a physical therapist will guide you through exercises to maintain or improve shoulder range of motion and flexibility, strengthen the muscles around your shoulder to provide better support, improve posture and body mechanics); and corticosteroid injections (in some cases, your doctor may suggest an injection of corticosteroid medication into the area to reduce inflammation and pain).

When is surgery considered for QSS?

Surgery is usually considered if non-surgical treatments haven't significantly improved your symptoms after about six weeks or more; symptoms are severe or progressively worsening; or there's clear evidence of nerve damage or significant compression.

What does the surgical procedure involve?

The goal of surgery, called decompression, is to relieve pressure on the axillary nerve and posterior circumflex humeral artery. This typically involves making a small incision at the back of your shoulder; identifying the compressed nerve and artery; carefully removing or cutting any fibrous bands, scar tissue, or other abnormal structures that are causing the compression. The procedure is designed to free up the nerve and artery, allowing them to function normally.

What are the potential risks of surgery?

As with any surgery, there are potential risks, though QSS surgery is generally safe. These can include infection, bleeding, damage to surrounding nerves or blood vessels, scarring, persistent pain or incomplete relief of symptoms, and reaction to anesthesia. Your surgeon will discuss these risks with you in detail.

What do I need to do before surgery?

Your healthcare team will provide specific instructions, but generally, you may need to undergo a pre-operative physical examination and blood tests; stop certain medications (e.g., blood thinners, some anti-inflammatory drugs) a week or two before surgery; arrange for someone to drive you home after surgery and help you during the first few days of recovery; and avoid eating or drinking for a certain period before the surgery.

What can I expect immediately after surgery?

You will likely have your arm in a sling to help it rest and heal. You may experience some pain, which will be managed with medication. Your surgical site will be covered with a dressing. Your surgeon will give you instructions on wound care and activity restrictions.

How long is the typical recovery period?

Recovery times vary for each person, depending on the severity of the condition and how long the nerve was compressed. First few weeks (0-2 weeks): Focus on rest, pain management, and protecting the surgical site. Gentle elbow and wrist movements will be encouraged. Weeks 2-6: You will start physical therapy, focusing on gentle range-of-motion exercises for your shoulder. After 6 weeks: As healing progresses, your physical therapist will introduce strengthening exercises to rebuild muscle strength. Overall, it can take several weeks to months to feel significant improvement, as nerve healing is a slow process.

What does rehabilitation/physical therapy involve?

Physical therapy is crucial for a successful recovery. Your therapist will design a personalized program that may include pain and swelling management (using ice, gentle massage, or other techniques); range of motion exercises (to restore full movement in your shoulder); strengthening exercises (targeting the muscles around your shoulder, including the deltoid and teres minor, which may have been weakened); postural correction (to improve overall shoulder mechanics); and activity-specific training (gradually reintroducing movements related to your work, sports, or daily activities).

How will pain be managed?

Your doctor will prescribe pain medication to help manage discomfort after surgery. This may include prescription pain relievers (e.g., opioids for a short period); over-the-counter pain relievers (e.g., acetaminophen, ibuprofen) as recommended by your doctor. You may also use ice packs to reduce localized pain and swelling.

When can I expect to return to daily activities, work, driving, and sports?

This timeline varies greatly based on your recovery progress and the demands of your activities. Daily activities: Light daily activities can usually be resumed within a few days to weeks. Driving: You can typically drive once you are no longer taking strong pain medications and have sufficient control and range of motion in your shoulder to safely operate a vehicle (often a few weeks after surgery). Work: Return to work depends on the nature of your job. Light, desk-based work might be possible within a few weeks, while jobs requiring heavy lifting or repetitive overhead movements will take longer, potentially several months. Sports: A gradual return to sports, especially overhead activities, will be guided by your physical therapist and surgeon, often not for several months after surgery. Full return to competitive sports may take 3-6 months or longer.

What is the expected long-term outcome?

For many patients, surgical decompression of QSS provides significant relief from pain, numbness, and weakness, allowing them to return to their normal activities, including sports. Nerve healing can be slow, so improvement may continue for several months. While some mild symptoms may occasionally linger, the goal is to significantly improve your quality of life and shoulder function.

Post-Operative Protocols

Arthroscopic Posterior Bankart Repair Protocol

Phase-by-phase post-operative rehabilitation protocol for Arthroscopic Posterior Bankart Repair to guide recovery and physical therapy.

A structured rehabilitation plan is essential for optimal recovery after surgery. On this page, we outline the phase-based protocol for Arthroscopic Posterior Bankart Repair to guide you and your physical therapist through a safe recovery.

An arthroscopic posterior Bankart repair is a surgical procedure performed to restore stability to the shoulder joint after a tear of the posterior labrum (typically caused by posterior shoulder instability or subluxation). Rehabilitation following this procedure focuses on protecting the healing labrum and capsule while gradually restoring range of motion, muscle strength, and functional stability. Posterior instability protocols require strict precautions regarding posterior joint loading and specific shoulder positions to prevent stretching or disruption of the repair.

Phase 1: Protection and Early Motion (Weeks 0-6)

The primary focus of this phase is to protect the posterior capsule repair, control pain and inflammation, and initiate gentle passive and active-assisted range of motion (PROM/AAROM) within safe, restricted limits.

Goals: Protect the surgical repair; Minimize pain and inflammation; Initiate early passive and active-assisted range of motion (PROM/AAROM) within safe boundaries; Maintain distal extremity mobility (elbow, wrist, and hand); Ensure proper posture.
Precautions & Restrictions: Wear the shoulder sling at all times, including during sleep (may remove only for hygiene and designated exercises); Avoid any posterior loading or weight-bearing on the operative arm; Avoid internal rotation (IR) past 0 degrees (neutral) or a maximum of 20 degrees; Avoid horizontal adduction (cross-body movement); Limit forward flexion to 90 degrees during weeks 0-4, progressing to 120 degrees at weeks 5-6; Avoid active internal rotation (no resisted IR).
Suggested Exercises: Pendulum exercises (gentle circular movements); Passive and active-assisted forward flexion (in supine, limiting range as noted); Passive external rotation (ER) in the plane of the scapula (safe progression as tolerated); Elbow, wrist, and hand active range of motion; Submaximal shoulder shrugs and scapular retraction (no resistance); Submaximal pain-free glenohumeral isometrics (abduction, external rotation only; NO internal rotation or extension isometrics).
Criteria to Progress: At least 6 weeks post-surgery; Minimum forward flexion to 90 degrees; Minimal pain and no signs of posterior joint subluxation; Clearance from the orthopaedic surgeon.

Phase 2: Active Motion and Early Strengthening (Weeks 6-12)

In this phase, the sling is discontinued, and the focus shifts to restoring full active range of motion (AROM), improving scapular dynamics, and starting gentle rotator cuff and periscapular strengthening.

Goals: Gradually discontinue sling use; Restore full active range of motion (AROM) in all planes; Re-establish normal scapulohumeral rhythm; Initiate light rotator cuff and scapular strengthening; Prevent posterior capsular tightness while avoiding posterior stress.
Precautions & Restrictions: Avoid sudden, jerking movements; No heavy lifting or pushing/pulling; Avoid weight-bearing exercises (e.g., push-ups, planks, or weight bearing through the elbow/hand); Monitor posterior joint pain; do not push through pain.
Suggested Exercises: Active-assisted and active forward flexion to tolerance; Gradual progression of active internal rotation (IR) and horizontal adduction (as tolerated, within pain-free limits); Scapular strengthening (serratus punches, scapular clocks, low rows); Rotator cuff strengthening using light resistance bands or light weights (active external rotation, abduction, extension; progress internal rotation only as pain and control allow); Core and lower body conditioning.
Criteria to Progress: Full active range of motion (AROM) compared to the uninvolved side (or near-full motion without pain); Good scapular control during active elevation; Ability to perform light resistance exercises without pain or compensation.

Phase 3: Progressive Strengthening and Advanced Rehab (Weeks 12-18)

The goal is to build muscle strength, endurance, and dynamic stability, with a focus on restoring normal neuromuscular control of the rotator cuff and scapula during more complex movement patterns.

Goals: Achieve full pain-free range of motion (ROM) in all planes; Improve rotator cuff and periscapular muscular strength and endurance; Enhance dynamic stability and neuromuscular control; Begin early proprioceptive and eccentric training.
Precautions & Restrictions: Avoid high-impact activities or sports; Avoid heavy pressing exercises (such as bench press or heavy overhead press) that load the posterior shoulder; Maintain proper form and control during all strengthening exercises.
Suggested Exercises: Progressed resistance band and dumbbell exercises for the rotator cuff (external/internal rotation, scaption, prone horizontal abduction); Closed-chain stabilization exercises (e.g., quadruped weight shifts, wall slides; progress to light weight-bearing as tolerated); PNF (Proprioceptive Neuromuscular Facilitation) diagonal patterns; Dynamic scapular stability drills; Core, hip, and lower extremity strength integration.
Criteria to Progress: Full, pain-free active ROM; Rotator cuff and scapular strength at least 4/5 or 80% of the contralateral side; No pain or instability during progressive strengthening; Clearance from the therapist and surgeon.

Phase 4: Return to Activity and Sports (Weeks 18-24+)

This phase prepares the patient for a safe return to recreational activities, manual work, or sports through advanced strengthening, plyometrics, and sport-specific training.

Goals: Restore maximal strength, power, and endurance; Re-establish full dynamic joint stability under high-velocity loads; Safe return to sport-specific or work-specific activities; Establish a long-term home maintenance exercise program.
Precautions & Restrictions: Gradual return to full-contact sports or heavy manual labor; Avoid sudden increases in exercise volume or intensity; Discontinue any exercise that reproduces shoulder pain or posterior instability sensations.
Suggested Exercises: Advanced dynamic strengthening (eccentric cuff training, plyometric medicine ball throws and catches); Sport-specific training drills (throwing, swimming, racket sports); Work-specific rehabilitation (lifting, reaching, push/pull activities); Gradual return-to-sport or return-to-work program; Continued home exercise and conditioning program.

These guidelines represent a standard rehabilitation protocol. Individual recovery rates vary significantly depending on the size of the repair, bone/tissue quality, and general patient health. Your surgeon may modify this protocol specifically for you.

Disclaimer: This protocol is for educational purposes and is not a substitute for professional medical advice. Always consult your surgeon or physical therapist before performing any exercises or modifying activity restrictions.

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