Dr Puah Ken Lee 潘健理
Orthopaedic Surgeon
Shoulder, Elbow & Sports Injuries
Practising at Mount Elizabeth Novena Hospital, Singapore
Appointments by prior arrangement
Dr Puah Ken Lee 潘健理
Orthopaedic Surgeon
Shoulder, Elbow & Sports Injuries
Mount Elizabeth Novena Hospital, Singapore
✔ Subspecialty Focus in Shoulder & Elbow, Sports Injuries
✔ Practising at Mount Elizabeth Novena Hospital
✔ Evidence-based treatment, Individualised Care
Introduction
An acromioclavicular (AC) joint injury, commonly known as a shoulder separation, occurs when the ligaments connecting the collarbone (clavicle) to the shoulder blade (acromion) are stretched or torn.
Unlike a shoulder dislocation, where the ball comes out of the socket, an AC joint injury affects the joint at the top of the shoulder.
Most AC joint injuries occur after a fall directly onto the shoulder during sports or cycling accidents.
What is the AC Joint?
The AC joint is where the collarbone (clavicle) meets the acromion, which forms part of the shoulder blade.
Although it is a small joint, it plays an important role by allowing coordinated movement between the shoulder blade and collarbone during arm elevation.
Strong ligaments stabilise the joint:
- Acromioclavicular ligaments
- Coracoclavicular ligaments
- Surrounding muscles including the deltoid and trapezius
When these ligaments are injured, the collarbone may become unstable or appear prominent.
What Causes an AC Joint Injury?
The injury usually results from a direct impact onto the point of the shoulder.
Common causes include:
- Cycling accidents
- Falls while skiing or snowboarding
- Rugby and football injuries
- Martial arts
- Falls from standing height
- Road traffic accidents
Young active adults are most commonly affected.
Symptoms
Patients commonly experience:
- Pain over the top of the shoulder
- Swelling
- Bruising
- Difficulty lifting the arm
- Pain when reaching across the body
- Pain during pushing movements
- Tenderness directly over the AC joint
More severe injuries may produce:
- A visible bump over the collarbone
- Shoulder deformity
- A sensation that the shoulder is unstable
How is an AC Joint Injury Diagnosed?
Diagnosis begins with a careful history and physical examination.
Your orthopaedic surgeon will assess:
- Location of pain
- Shoulder stability
- Tenderness over the AC joint
- Arm movement
- Associated shoulder injuries
X-rays
X-rays confirm the diagnosis and determine the severity of the injury.
Special stress views are occasionally required.
MRI
MRI may be recommended when:
- Symptoms persist
- A rotator cuff tear is suspected
- Labral injuries are suspected
- Surgery is being considered
Classification of AC Joint Injuries
AC joint injuries are commonly classified using the Rockwood classification.
Grade I
- Mild ligament sprain
- Joint remains stable
- No significant deformity
Grade II
- Partial ligament tear
- Mild elevation of the collarbone
Grade III
- Complete ligament rupture
- Noticeable bump over the shoulder
Grades IV–VI
These represent more severe injuries with significant displacement of the collarbone.
Surgical treatment is often recommended.
Non-Surgical Treatment
Most AC joint injuries recover without surgery.
Treatment may include:
- Sling for comfort
- Ice application
- Pain medication
- Early range-of-motion exercises
- Physiotherapy
- Gradual strengthening
Many patients return to everyday activities within several weeks.
Higher-demand athletes may require a longer rehabilitation programme.
When is Surgery Needed?
Surgery may be considered when there is:
- Severe ligament disruption
- Significant displacement
- Persistent pain after rehabilitation
- Ongoing shoulder instability
- High-demand overhead athletes
- Manual workers requiring heavy lifting
Treatment is individualised according to your age, occupation, sporting activities and expectations.
Surgical Treatment
The aim of surgery is to restore the normal position of the collarbone and reconstruct the damaged ligaments.
Modern techniques may include:
- Arthroscopic-assisted ligament reconstruction
- Suspensory fixation devices
- Tendon graft reconstruction in chronic injuries
Early surgery may produce better outcomes in selected acute injuries.
Recovery After Treatment
Recovery varies depending on the severity of the injury.
Typical timelines are:
| Activity | Approximate Time |
|---|---|
| Sling | 1–4 weeks |
| Desk work | 1–2 weeks |
| Driving | 2–6 weeks |
| Light exercise | 6 weeks |
| Gym strengthening | 8–12 weeks |
| Contact sports | 3–6 months |
Individual recovery differs depending on the injury and treatment chosen.
Frequently Asked Questions
Is an AC joint injury the same as a shoulder dislocation?
No. An AC joint injury affects the joint between the collarbone and shoulder blade. A shoulder dislocation occurs when the ball comes out of the shoulder socket.
Will the bump disappear?
Not always.
Many patients retain a small prominence over the collarbone even after successful recovery. This is often cosmetic and does not affect shoulder function.
Can I avoid surgery?
Yes.
Most Grade I and Grade II injuries, and many Grade III injuries, recover well with non-surgical treatment.
When can I return to sports?
Return to sport depends on:
- Pain control
- Shoulder strength
- Range of motion
- Type of sport
- Severity of injury
Contact sports generally require a longer recovery.
When Should You See an Orthopaedic Surgeon?
Seek assessment if you have:
- A painful bump after a fall onto the shoulder
- Difficulty lifting your arm
- Persistent pain despite rest
- Shoulder instability
- Pain preventing return to work or sports
Early assessment helps determine the severity of the injury and whether surgery may improve long-term function.
Why Choose Dr Puah Ken Lee?
Dr Puah Ken Lee is an orthopaedic surgeon in Singapore with a practice focused on shoulder, elbow and sports injuries. He believes that patients should understand the full range of treatment options before deciding on surgery. Many AC joint injuries can be managed successfully without an operation, while selected severe injuries may benefit from timely surgical stabilisation.
Related Conditions
- Return to Sport After Injury
- Shoulder Pain
- Shoulder Dislocation
- AC Joint Arthritis
- Rotator Cuff Tear
- SLAP Tear
- Labral Tear
- Sports Injuries
- Shoulder Surgery
- First Orthopaedic Consultation
For a full overview of shoulder conditions, visit Shoulder Specialist Singapore
Dr Puah is regularly invited to teach shoulder surgery internationally
Specialist Care for Shoulder Injuries in Singapore
Dr Puah is an orthopaedic surgeon specialising in shoulder, elbow and sports injuries. He provides personalised care tailored to each patient’s condition and activity level.
Consultations are available at Mount Elizabeth Novena.
If you are experiencing shoulder pain that is affecting your daily life or sports, early assessment can help guide appropriate treatment.
Book a consultation or contact the clinic to discuss your condition.
Book a Consultation
Book a consultation or contact the clinic via WhatsApp to get started
Book a consultation at 360 Orthopaedics, Mount Elizabeth Novena
AC joint injuries are common but treatable. Early diagnosis and appropriate management can improve outcomes and prevent long-term problems.
Dr Puah Ken Lee is an orthopaedic surgeon in Singapore specialising in shoulder, elbow and sports injuries at 360 Orthopaedics, Mount Elizabeth Novena. Patients with persistent shoulder pain after an injury are encouraged to seek specialist evaluation.