Introduction
Shoulder instability is a complex and often recurrent condition that can significantly impact athletes, particularly those involved in contact sports like rugby.
English rugby player Jack Willis sustained a severe shoulder dislocation during a tackle, which required surgical intervention and months of rehabilitation. His successful return to international rugby highlights how with timely surgical management and a high level, structured rehabilitation programme athletes can continue to play sport at an elite level following this injury.
This article will explore the condition, its causes, diagnosis, management strategies, including both surgical intervention and the role of physiotherapy and strength rehabilitation.
We will also highlight considerations for female athletes in rugby, particularly the challenges posed by hypermobility.
What Is Shoulder Instability?
Shoulder instability refers to an issue whereby the shoulder joint is not suitably controlled and doesn’t remain securely in its proper position. This condition may manifest as recurrent dislocations, where the joint surfaces are fully dislocated, or subluxations, where the joint partially dislocates but often then self-corrects.
Instability can develop from acute trauma, such as a nasty fall or tackle, or repetitive mild injury or overuse, particularly in athletes involved in overhead or contact sports.
Some people can have a predisposition to this type of injury due to generalised joint laxity or hypermobility, which further increases their risk of injury.
Types of Instability
- Type I – Traumatic: This is often linked to high-impact sports, where dislocations are typically caused by tackles or falls.
- Type II – Atraumatic: Usually results from hypermobility (more common in women) or repetitive strain without a single major injury.
- Type III – Multidirectional: A problem with muscle patterning; a combination of directions in which instability occurs, also more common in hypermobile individuals.
Anatomy of the Shoulder Joint
The shoulder is a ball-and-socket joint formed by the head of the humerus (ball) and the glenoid fossa of the scapula (socket).
Unlike the hip joint, which is a deep and highly stable ball-and-socket structure, the shoulder joint, also known as the glenohumeral joint, is designed with a relatively large humeral head (ball) articulating with the small, shallow glenoid cavity (socket).
This makes the shoulder joint an inherently less stable but very mobile structure, allowing movement in multiple directions.
Bones of the Shoulder:
- Humerus: The long bone of the upper arm, with a rounded head (ball) that fits into the glenoid (socket).
- Scapula (Shoulder Blade): Contains the glenoid cavity (socket), which articulates with the humeral head (ball).
- Clavicle (Collarbone): This bone connects the scapula to the sternum, giving the joint further support and stability.
Soft Tissue Structures Providing Shoulder Stability
Stability in the shoulder relies on a combination of static stabilisers (ligaments, the labrum, and joint capsule) and dynamic stabilisers (rotator cuff and scapular muscles). Damage to any of these components can compromise joint stability.
Labrum
A fibrocartilaginous (thick, slightly squishy soft tissue) ring that deepens the socket, enhancing joint stability.
Ligaments
- Superior, Middle, and Inferior Glenohumeral Ligaments (SGHL, MGHL, IGHL): Provide stability at different positions of shoulder abduction (lifting the arm out to the side, away from your body) and rotation.
- Coracohumeral Ligament: Reinforces the superior (upper) part of the joint capsule.
Joint Capsule
A fibrous sheath (like a sock) that encloses the joint and provides static stability.
Rotator Cuff Muscles
There are four muscles and their tendons which play a crucial role in the dynamic stabilisation of the shoulder joint, by centring the humeral head in the glenoid cavity.
- Supraspinatus: Assists in shoulder abduction – lifting your arm out to the side.
- Infraspinatus: Facilitates external rotation – rotating your arm outwards away from your body.
- Teres Minor: Also contributes to external rotation.
- Subscapularis: Responsible for internal rotation – rotating your arm inwards, across your body.
Scapular Stabilisers: Muscles such as the serratus anterior and trapezius also support shoulder movements and stability.
The combination of static (ligaments and labrum) and dynamic (muscles) stabilisers ensures that the shoulder remains as stable as possible stable during complex movements such as overhead throwing and catching.
Causes of Shoulder Instability in Rugby
Rugby players are particularly susceptible to this injury due to the high-contact nature of the sport. Tackling, scrummaging, and collisions frequently place the shoulder in vulnerable positions, leading to traumatic dislocations.
Repeated injury weakens the joint’s static and dynamic stabilisers, increasing the risk of recurrent dislocations and leading to chronic shoulder instability.
Female Athletes and Shoulder Instability
It’s important to recognise the unique challenges female rugby players and other athletes face with conditions like shoulder instability.
Women often have higher rates of joint hypermobility, which increases the risk of shoulder instability.
Hypermobility
Hypermobility refers to an increased range of motion in joints beyond what is considered normal.
This condition is often assessed using the Beighton score, which evaluates factors such as the ability to bend the thumb to the forearm and hyperextension of the elbows and knees. A score of 4 or more is generally indicative of hypermobility.
Female Anatomy and Physiology
The female shoulder may be more predisposed to instability due to differences in connective tissue composition and hormonal influences that affect ligament and soft tissue laxity.
Hypermobile athletes may have weaker static stabilisers (especially ligaments), placing greater demand on the dynamic stabilisers, including the rotator cuff and scapular muscles. This imbalance increases the risk of shoulder subluxations or dislocations during high-impact activities like rugby tackles.
Diagnosis of Shoulder Instability
Clinical Assessment
The medical consultation and examination will include the following:
- Detailed medical history, including the mechanism of injury and number of prior dislocations.
- Physical examination, including joint range of movement, muscle strength. They will also likely perform special clinical tests such as the apprehension test and sulcus sign.
Your specialist will need to assess your shoulder and may also look at other joints to ensure they have a full picture of your injury.
Imaging and Diagnostics
X-rays: These might be needed to detect fractures or bone defects.
MRI: Provides detailed imaging of soft tissue injuries, including labral tears or rotator cuff (muscle) tears
Diagnostic Ultrasound for Shoulder Instability
Diagnostic ultrasound is an effective and dynamic tool for assessing shoulder instability. It provides real-time imaging, allowing clinicians to evaluate shoulder movement and detect abnormalities such as labral tears, joint effusion, and soft tissue injuries.
Ultrasound is particularly useful in confirming correct relocation of a dislocated shoulder and assessing the integrity of stabilising structures during movement.
Unlike MRI or X-rays, ultrasound does not involve radiation exposure and can be performed quickly in a clinical setting.
At London Bridge Sports Medicine (LBSM), our sports medicine specialists offer diagnostic ultrasound as part of their standard assessment, providing immediate insights without the need for onward referrals, ensuring a more efficient and streamlined patient experience.
How is Shoulder Instability Treated?
Treatment for shoulder instability depends on the severity of the condition and the individual’s activity level.
Conservative management is often the first approach, particularly for those with atraumatic or mild instability.
Conservative Treatment
This involves rehabilitation aimed at strengthening the rotator cuff and scapular muscles, improving proprioception, and restoring shoulder stability. Pain management and gradual return to activity are also prioritised.
Conservative management is typically recommended for patients who have not experienced recurrent dislocations or those with multidirectional instability without significant structural damage.
The Role of Physiotherapy
Physiotherapy is the cornerstone of both non-operative and post-surgical management of shoulder instability.
Physiotherapists use targeted exercises to strengthen the rotator cuff and scapular stabilisers, which are important for maintaining dynamic stability of the shoulder joint.
They also address proprioception—the body’s sense of joint position—which is often impaired following this type of injury.
Key Components of Physiotherapy:
- Pain Management: Initial treatment includes rest and modalities such as ice. Sometimes slings are used for a period of immobilisation.
- Range of Movement (ROM) Restoration: Gentle exercises to regain full movement of the shoulder joint.
- Strengthening Exercises: Progressive loading to rebuild muscle strength in the rotator cuff, deltoid, and scapular stabilisers.
- Proprioceptive Training: Balance and stability drills to re-educate the shoulder’s response to movement and external forces.
- Functional Training: Sport-specific drills designed to mimic real athletic movements.
Below are some commonly recommended exercises:
- Isometric Rotator Cuff Exercises: Holding resistance with minimal shoulder movement.
- Scapular Strengthening: Rows, scapular squeezes.
- Dynamic Stabilisation Drills: Ball rolls on walls.
- Proprioceptive Exercises: Balance boards with upper limb engagement.
- Progressive Resistance Training: Incorporating gym exercises such as dumbbell external rotations and bench presses with proper form.
Importance of Exercise
Consistent and properly guided exercise is essential for long-term shoulder joint health.
Strength training helps protect the shoulder by ensuring the muscles around the joint provide good support.
Core and scapular stability exercises help maintain proper shoulder mechanics during movements.
Furthermore, regular exercise improves muscle endurance levels and prevents fatigue-related injuries.
By combining expert sports medicine guidance with a structured physiotherapy program, athletes can recover more effectively, reduce the risk of re-injury, and return to their chosen sport with improved performance and resilience.
Injury Prevention Strategies
- Strength and Conditioning: Targeting the rotator cuff and scapular muscles.
- Tackling and Falling Technique Training: Proper form reduces injury risk.
- Load Management: Avoiding overuse injuries through well-structured training.
Surgical Treatment
Surgery is considered when conservative treatments fail or if the patient experiences frequent dislocations that significantly affect daily activities or athletic performance.
Candidates for surgery often include:
- Athletes engaged in high-impact sports: Contact sports like rugby increase the risk of recurrent dislocations.
- Patients with structural injuries: Labral tears, glenoid bone loss, or large Hill-Sachs lesions may require surgical intervention.
- Failure of conservative treatment: Persistent instability and ongoing symptoms despite dedicated rehabilitation efforts.
Early surgical intervention is sometimes preferred for high-level athletes as it can reduce the risk of further damage and help athletes return to their sport more confidently and safely.
Research indicates a recurrence rate of up to 42% in non-operative cases but drops to 7% with arthroscopic Bankart repair (Robinson et al., 2008).
When to Seek Professional Advice
If you sustain a shoulder dislocation or suspect you have chronic shoulder instability caused by lax joints, it is essential to seek an assessment by a sports doctor or specialist. A quick and accurate diagnosis can significantly improve the outcome of your injury by facilitating early management and tailored treatment plans.
Following a first-time shoulder dislocation, you will need to be seen immediately by a pitch side medic or attend A &E to have your arm assessed and shoulder relocated. This needs to be done as soon as possible following the injury.
Do not try to pop your arm back in yourself – you could damage the tissues, nerves and blood vessels around the shoulder joint.
Conclusion
Shoulder instability is a challenging but manageable condition for rugby players and other athletes. With a combination of physiotherapy, strengthening exercises, and surgical interventions when appropriate, athletes can make a successful return to sport.
For female athletes, addressing hypermobility through specific, individualised programmes can manage the condition and prevent further injury.
References
Farrar, N. G., Malal, J. J. G., Fischer, J., & Waseem, M. (2013). An overview of shoulder instability and its management. The Open Orthopaedics Journal, 7, 338-346.
Robinson, C. M., Jenkins, P. J., White, T. O., Ker, A., & Will, E. (2008). Primary arthroscopic stabilization for a first-time anterior dislocation of the shoulder: A randomized, double-blind trial. Journal of Bone and Joint Surgery, 90(7), 708-721.
