62 Dislocations, Subluxations, and Frozen Shoulder

Dislocations and Subluxations

Joint dislocations involve the loss of contact between one or more bones in a joint.  Dislocations often are caused by accidents during sports, falls, workplace mishaps, or other forms of trauma (e.g., car crashes).

Joint subluxations involve the partial loss of contact between one or more bones in a joint.  Subluxations (unlike dislocations) often return to their normal position on their own.

Joints that are susceptible to both dislocation and subluxation are the shoulders, hips, elbows, wrists, fingers, ribs, and kneecaps.

Examples of Joint Dislocations:

Shoulder (glenohumeral) dislocations are the most common type of dislocation in adults, which is thought to be due to its high degree of mobility and therefore reduced stability in comparison with other joints.  Shoulder dislocations typically occur as a result of traumatic injury, though loose capsular ligaments and previous shoulder dislocations can be predisposing factors.  Shoulder dislocations usually involve the head of the humerus being thrust out of the glenoid socket in an anterior and inferior direction.  The scapula provides posterior support and the glenohumeral joint is more vulnerable on its anterior side.  That being said, although rare, dislocation can occur posteriorly as well.  Other dislocations involving the scapula can occur (e.g., involving the acromioclavicular joint) though these are not typically called shoulder dislocations.

Elbow dislocations are the most common dislocation in children, and second most common in adults.  The elbow is a more stable joint than the shoulder with more limited range of motion.  The elbow is a biaxial hinge joint and the shoulder is triaxial ball joint.  The bony olecranon hook of the ulna helps to keep the humerus in place, and also means considerable force is required to dislocate the elbow, frequently fracturing the ulna in the process, especially in an adult.  In children the hook of the ulna is less formed, leading to easier dislocations particularly when pulling or swinging a child by their arms (when in an extended arm position).  Sports (e.g., football and wrestling) account for approximately 10-50% of elbow dislocations.

Risk Factors – Dislocations

Sports as well as falls are risk factors for shoulder and elbow dislocations.  Hyperlaxity of joints as well as the shape of bone ends and cerebral palsy at times can predispose to shoulder dislocations.

Signs and Symptoms – Shoulder Dislocations

Shoulder Dislocations:  Signs and symptoms include the feeling of the joint popping out, as well as the tearing of ligaments, tendons, and/or articular capsule.  Inflammation, characterized by intense pain, swelling, redness, and warmth, as well as bruising, and reduced muscular strength are common.  The pain or numbness which can radiate down the limb results from sensory neurons in the articular capsule and nearby structures being stretched.

Shoulder dislocations often have the appearance of deformed joints and can also be palpated.  Dislocations will also be noted to exhibit poor range of motion.

At times, a patient can report having very loose joints (hyperlaxity) and they are able to roll their shoulder back into position without assistance.

The most common complication of shoulder dislocation is recurrences, though rotator cuff muscle tears and nerve or vascular damage can also occur which can lead to loss of range of motion, reduced strength and sensory deficits.  Additionally, dislocations may occur at the same time as bone fractures.  Dislocations and associated trauma are predisposing risk factors for the development of compartment syndrome and myositis ossificans.

Diagnostic Tools – Dislocations

Physical examination coupled with imaging (e.g., x-rays) are often used, before and after reduction of the joint (putting the joint back in place).  MRI can be helpful in assessing ligament, tendon, and capsular damage.  With shoulder dislocations, the tearing of ligaments and rotator cuff tendons frequently occurs which will result in muscle weakness (which will also be noted in strength tests).

Treatment – Dislocations

Depending on the injury, reduction of the joint may be done while the patient is conscious, or while sedated.   Typically, neurovascular examinations are performed before and after reduction to ensure that nerve and blood vessel injury is assessed and prevented if possible.  Analgesics and NSAIDs are often used to reduce pain and inflammation in the initial days following the dislocation event.

Shoulder Dislocations – treatment strategies:

With shoulder dislocations, after reduction, immobilization of the joint with a sling for 1-3 weeks is usually recommended.  Minor tears of ligaments and tendons of the rotator cuff muscles may heal on their own however surgery using arthroscopy may be performed to repair tears.

Once healing has progressed, physical therapy is an important phase of rehabilitation in restoring, both strength and flexibility of the surrounding soft tissues (ligaments, tendons, muscles) as well as ensuring range of motion (ROM) is restored.  Scar tissue that has formed will start to shorten and stretching exercises are required to ensure ROM is not compromised – which can result in adhesive capsulitis also known as “frozen shoulder”.

Ramping up to more vigorous rehabilitative therapy is advantageous in regaining rotator cuff strength as well as maintaining ROM.  Swimming is often recommended.

Summary:

•  Dislocation:
  • Loss of contact between one or more bones in a joint
  • Most common in shoulder, elbow, wrist, finger, hip, and knee
  • Shoulder most susceptible due to its high mobility
  • Can occur due to joint disease or previous damage
  • Can damage surrounding ligaments, muscles, nerves, and blood vessels
  • Symptoms: pain, tenderness, possible anesthesia or paralysis
  • Diagnosis: imaging (X-ray, MRI, arthroscope)
  • Treatment: reduction, anesthetics, PRICE (protection, rest, ice, compression, elevation), possible surgical repair
  • Rehabilitation: physiotherapy to regain function and range of motion
• Subluxation:
  • Partial loss of contact between one or more bones in a joint
  • Less severe than dislocation
  • Similar signs and symptoms: pain, stiffness
  • Can lead to frozen shoulder (adhesive capsulitis) if not properly rehabilitated
  • Importance of physiotherapy to prevent loss of range of motion
• Frozen Shoulder:
  • Also known as adhesive capsulitis
  • Excessive scarring reduces range of motion long-term
  • Importance of following doctor and physiotherapist guidance for recovery and rehabilitation