Hill-sachs Lesion

A Hill-Sachs lesion is an injury to the humeral head (the ball of the shoulder joint) that occurs during a shoulder dislocation. It is essentially a compression fracture or dent in the humeral head that happens when the head of the humerus impacts the edge of the glenoid (the socket of the shoulder joint) during the dislocation.
This type of lesion is commonly associated with anterior shoulder dislocations, where the shoulder dislocates forward. The lesion can range from small and asymptomatic to larger, more severe injuries that may cause ongoing shoulder instability or difficulty with certain shoulder movements.

The primary cause of a Hill-Sachs lesion is shoulder dislocation, particularly in an anterior (forward) direction. However, several factors and circumstances can contribute to its development. Here are the main causes:

1. Anterior Shoulder Dislocation:
Most common cause is during anterior dislocation, the head of the humerus collides with the edge of the glenoid, resulting in a compression fracture or indentation on the posterior aspect of the humeral head.

2. Trauma or Injury:
High-impact falls (e.g., falling onto an outstretched hand).
Sports injuries, especially contact sports like rugby, football, or wrestling.
Motor vehicle accidents can also lead to shoulder dislocation and subsequent Hill-Sachs lesions.

3. Recurrent Shoulder Dislocations:
Chronic shoulder instability can lead to repeated dislocations, increasing the likelihood of a Hill-Sachs lesion or worsening an existing one.
Activities that involve excessive, repetitive shoulder motion (e.g., overhead sports like tennis or volleyball) may predispose to recurrent dislocations.

4. Congenital or Anatomical Factors:
Individuals with loose or hypermobile joints or abnormal shoulder anatomy may be at higher risk of shoulder dislocation and thus cause Hill-Sachs lesions.

5. Violent Overhead or Rotational Movements:
Any sudden, forceful overhead or rotational movement (e.g., during a seizure or electric shock) can cause shoulder dislocation, leading to a Hill-Sachs lesion.

6. Inadequate Post-injury Rehabilitation:
Poor rehabilitation after an initial shoulder dislocation can lead to recurrent dislocations, increasing the chance of developing a Hill-Sachs lesion.
The severity of the lesion usually correlates with the severity or frequency of dislocation events.

The symptoms of a Hill-Sachs lesion primarily relate to shoulder instability and discomfort, often associated with a prior shoulder dislocation. The lesion itself may not cause direct pain but contributes to instability, leading to symptoms. Here are the common symptoms:

1. Shoulder Instability:
The shoulder may feel loose or like it could slip out of place, especially during certain movements, such as lifting the arm overhead or rotating it outward.

2. Pain:
General shoulder pain, especially when moving the arm into a position that places stress on the injured area (e.g., external rotation or overhead activities).
Pain may increase during physical activities or after a dislocation event.

3. Limited Range of Motion:
Difficulty raising the arm, particularly in external rotation (rotating the arm outward).
Reduced flexibility and stiffness in the shoulder joint.

4. Clicking, Popping, or Catching Sensation:
Sensation of the shoulder "catching" or "popping" during movement, indicating instability within the joint.

5. Recurrent Shoulder Dislocations:
Individuals with a Hill-Sachs lesion are at an increased risk for recurrent dislocations due to the altered shape of the humeral head. This may lead to frequent or repeated dislocations.

6. Weakness:
Muscle weakness, particularly when trying to lift objects or perform movements that engage the shoulder joint, may be felt due to the instability.

7. Swelling or Bruising (Post-Dislocation):
After a dislocation or trauma, swelling or bruising around the shoulder joint may be present, although this is more related to the dislocation event rather than the Hill-Sachs lesion itself.
If the lesion is large, symptoms can be more pronounced, with a higher risk of chronic instability and recurrent dislocations.


Pathology
The pathology of a Hill-Sachs lesion involves structural damage to the humeral head, typically caused by anterior shoulder dislocation. The lesion is a compression fracture or indentation on the posterior-lateral aspect of the humeral head, which occurs when the humerus impacts the edge of the glenoid cavity (the socket of the shoulder joint).
The primary pathological feature is a compression fracture or defect on the posterior-lateral aspect of the humeral head, caused by anterior dislocation of the shoulder.
Associated injuries, such as labral tears and damage to the glenoid rim, further complicate the pathology and increase the risk of recurrent shoulder instability.

Medication: Nonsteroidal Anti-inflammatory Drugs (NSAIDs), Acetaminophen (Paracetamol), Muscle Relaxants, Corticosteroid Injection, Opioids (for Severe Pain), Topical Analgesics, etc.
(NOTE: Medication should not be taken without the doctor's prescription.)

Surgery
Surgery for a Hill-Sachs lesion is usually indicated when the lesion is large or when recurrent shoulder dislocations occur due to instability. The goal of surgery is to restore shoulder stability, prevent future dislocations, and repair the damaged bone and soft tissue structures. Surgical options depend on the severity and size of the lesion, as well as associated injuries, such as Bankart lesions or glenoid bone loss.

Common Surgical Procedures for Hill-Sachs Lesion:

1. Arthroscopic Repair:
Procedure: Minimally invasive surgery where small incisions are made, and a camera (arthroscope) is inserted into the shoulder joint to assess and repair the lesion.

2. Remplissage Procedure:
This involves filling the defect in the humeral head by transferring part of the rotator cuff tendon (the infraspinatus tendon) and its capsule into the lesion.

3. Humeral Head Allograft (Bone Grafting):
A bone graft (often from a cadaver or synthetic material) is used to "fill in" the bony defect of the humeral head.

4. Humeral Head Osteotomy:
Procedure: Involves reshaping the humeral head by cutting and repositioning the bone to correct the defect.

5. Latarjet Procedure:
Procedure: Bone from the coracoid process (a part of the scapula) is transferred to the anterior aspect of the glenoid cavity to increase its depth and size, preventing dislocation.

6. Partial or Total Shoulder Replacement:
Procedure: Replacing part or all of the shoulder joint with a prosthetic implant.

Rest and Immobilization:
The shoulder may be immobilized in a sling for a period (usually 2–4 weeks) to allow healing.

Ice Therapy:
Apply ice to reduce inflammation and pain.

Transcutaneous Electrical Nerve Stimulation (TENS):
Purpose: TENS is commonly used for pain relief. It works by sending mild electrical impulses through the skin to stimulate nerves and reduce the perception of pain.
Application: Electrodes are placed around the shoulder joint to target the area of pain.
Effectiveness: TENS can help reduce discomfort during rehabilitation exercises or post-dislocation recovery, making therapy sessions more tolerable.

Neuromuscular Electrical Stimulation (NMES):
Purpose: NMES is used to strengthen weakened muscles by stimulating muscle with electrical impulses.
Application: Electrodes are applied to the muscles around the shoulder joint, such as the rotator cuff muscles or deltoid, to improve strength and stability in the shoulder. This is especially helpful after immobilization or surgery, where muscle atrophy may occur.
Effectiveness: NMES helps prevent muscle weakness and enhances muscle reactivation during rehabilitation.

Interferential Current (IFC) Therapy:
Purpose: IFC therapy is used to reduce pain and inflammation by delivering a low-frequency electrical current deep into the tissue. It is thought to promote healing and reduce swelling.
Application: Electrodes are placed in a cross pattern around the shoulder joint, and a low-frequency current penetrates deep into the tissue.
Effectiveness: IFC is beneficial in managing post-dislocation inflammation and improving pain control during early rehabilitation stages.

Ultrasound Therapy (with Electrical Stimulation):
Purpose: While ultrasound is not an electrical modality in itself, it is often combined with electrical stimulation for deep tissue healing and pain relief.
Application: The ultrasound device uses sound waves to generate heat deep within the tissues, while electrical stimulation may be applied concurrently to further improve pain relief and promote tissue healing.
Effectiveness: The heat from ultrasound improves blood flow, reduces inflammation, and accelerates tissue repair, which is especially useful during the recovery phase after injury or surgery.

Iontophoresis:
Purpose: Iontophoresis is used to deliver anti-inflammatory medications (like corticosteroids) through the skin using a mild electrical current.
Application: A medicated pad is applied to the affected area, and a low-level electrical current drives the medication into the tissue to reduce localized inflammation.
Effectiveness: This modality is helpful in reducing inflammation and pain in the shoulder, particularly after dislocation or surgery.

High-Voltage Pulsed Galvanic Stimulation (HVPGS):
Purpose: HVPGS is used for pain relief, reducing edema (swelling), and promoting tissue healing by delivering a high-voltage, low-amplitude current.
Application: Electrodes are placed around the injured area, and electrical pulses help to stimulate blood flow and reduce swelling.
Effectiveness: This can be used in the early stages of rehabilitation when there is significant pain and swelling, particularly after an acute dislocation or surgery.

Functional Electrical Stimulation (FES):
Purpose: FES is used to restore or enhance functional movement by using electrical stimulation to activate muscles in a coordinated manner.
Application: Electrodes are placed on key muscle groups to mimic natural movement, helping to improve shoulder function during the rehabilitation process.
Effectiveness: Useful in restoring muscle control and movement patterns, especially after surgery or prolonged immobilization.

Passive and Assisted ROM Exercises:
Gentle range-of-motion exercises like pendulum movements to prevent stiffness, focusing on pain-free motion.

Scapular Mobilization:
Gentle scapular mobilization to maintain scapulothoracic rhythm.


Isometric Exercises:

Gentle isometric exercises for the shoulder muscles (deltoid, rotator cuff) to maintain muscle tone without stressing the joint.

 

Active-Assisted ROM:

Gradually progress to active-assisted ROM exercises, such as using a pulley or wand to move the arm.

 

Stretching Exercises:

Focus on stretching the posterior capsule, rotator cuff, and other shoulder muscles to prevent stiffness.

 

Strengthening Exercises:

Begin strengthening the rotator cuff muscles (supraspinatus, infraspinatus, teres minor, subscapularis), which play a key role in shoulder stability.

Isometric to Isotonic Exercises:

Transition from isometric to isotonic exercises using light resistance bands.

Scapular Stabilization:

Exercises to strengthen the serratus anterior and lower trapezius to improve scapular control.

 

Proprioception and Neuromuscular Control:

Use proprioceptive exercises such as ball stability exercises to improve joint sense and stability.

Pendulum and Codman Exercises: To maintain joint mobility without stress.

 

Progressive Resistance Exercises:

Gradually increase resistance with bands, free weights, or dumbbells to strengthen the rotator cuff, deltoid, and scapular muscles.

Rotator Cuff Strengthening:

Focus on exercises like:

External and Internal Rotation:

Using resistance bands or weights.

Scapular Retraction/Protraction:

Using resistance bands.

Shoulder Shrugs and Rows:

For overall shoulder and scapular strength.

Closed-Chain Exercises:

These include exercises like wall push-ups, progressing to weight-bearing exercises (plank variations) to improve joint stability.

 

Core and Trunk Stabilization:

Engaging core muscles to improve overall shoulder function and stability during dynamic movements.

Functional Exercises:

Gradually introduce sports-specific or daily activity-related movements to restore function and prevent injury recurrence.

 

Dynamic Shoulder Stabilization:

Focus on dynamic stability exercises, such as throwing or catching exercises with a medicine ball, or sport-specific drills.

Plyometrics:

Advanced plyometric exercises like push-ups, ball throws, or other explosive movements may be introduced for athletes or individuals returning to high-demand activities.

Overhead Strengthening:

Gradually introduce overhead strengthening and functional movements, ensuring that the shoulder is stable and pain-free during these activities.

Endurance Training: Incorporate endurance-based exercises to help the shoulder withstand repetitive or prolonged activities without fatigue.

Functional Movement Patterns: Reinforce proper movement patterns during complex activities, like reaching, lifting, or throwing.

The patient is educated on proper movement mechanics, posture, and activity modifications to avoid future injuries. The patient is asked to avoid high-risk activities or movements that could lead to another shoulder dislocation, especially during the initial recovery period.