Aetiology
Post-traumatic (type III clavicle fractures)
Idiopathic
4 patterns
1. OA with osteophytes
- contribute to impingement

2. Osteolysis with resorption & gross osteoporosis
- due to repetitive microtrauma (eg weight lifters)


3. RA
4. Hyperparathyroidism
Symptoms
Anterosuperior shoulder pain
- difficulty sleeping on affected side
- pain radiates to trapezius / spasm
Signs

Tenderness to direct palpation is most reliable sign
- may feel osteophytes
- must compare to ensure other side is not tender (but may have bilateral ACJ OA)
Cross body adduction of arm
- tends to overlap with impingement
Diagnosis
LA + Cortisone
- inject into joint
- diagnostic / therapeutic
DDx
Intrinsic
- Impingement
- Calcific tendonitis
- ACJ gout
- ACJ sepsis
Extrinsic
- Cervical root C4/5
- shoulder tip pain from abdominal pathology
Xray
Zanca view
- AP 10° cephalic tilt with 50% penetration

Bone Scan
Not usually necessary

Management
Non-operative
Most patients respond well
NSAIDs
Activity modification
Steroid injection
Operative
Indications for surgery
- X-ray evidence of degenerative change
- tenderness at ACJ
- pain relieved by LA injection to ACJ
- failure of non operative treatment
Aim
Resect sufficient distal clavicle to prevent abutment
Options
1. Open excision distal clavicle
2. Arthroscopic resection
Open Excision of distal clavicle

Technique
- incision centered over the ACJ
- minimal takedown of deltopectoral fascia and anterior deltoid
- incise ACJ capsule longitudinally in midline
- elevate subperiosteally and repair later for stability
- resect 1cm only so as to not destabilise clavicle
- must leave conoid / trapezoid ligaments intact
90% success rate
Arthroscopic ACJ Resection
Advantage
- minimal incisions
- preserves superior AC ligament and deltoid
- quicker rehabilitation
Results
Freedman et al J Should Elbow Surg 2007
- routine GH scope initially
- identified subtle intra-articular changes not seen on MRI which were treated
- labral tears, partial RC tears
- resection performed via subacromial space
- very similar results at 1 year to open resection
Technique
1. Identify distal clavivle
- remove bursa and perform SAD
- use electrocautery from lateral portal to identify the distal clavicle (push down on clavicle repetitively)
- clean and identify clavicle anterior and posterior


2. Anterior portal
- placed just at lateral aspect of distal acromion
- remove anterior then posterior clavicle
- must remove full thickness of distal clavicle superiorly / be able to visualise superior AC ligament
- must not leave posterior edge




