Mike Nicholls, B.Sc., M.D., C.F.P.C., Dip. Sport Med.


Dear Doctor:
I am quite involved in hockey, but have become confused about the difference of 2 common injuries a couple of my teammates have had. Don has had a “shoulder dislocation”, while Steve has had a “shoulder separation”. Both injuries occurred when they were body checked in to the boards. What is the difference?

Shoulder injuries can be a source of ongoing disability and account for a significant amount of missed time from activity or work. As the shoulder is one of the most mobile and complex joints in the body, it must sacrifice stability for mobility. Designed as a non-weight bearing joint, activities that place great demands on the shoulder subject it to the risk of injury. Two relatively common injuries are a shoulder (glenohumeral) dislocation and a shoulder separation (acromioclavicular sprain). They are different injuries with different treatments and possibly different outcomes. A proper diagnosis by someone skilled at the examination of the shoulder becomes critical in ensuring that appropriate treatment is received.

Glenohumeral Dislocation – DON
A glenohumeral dislocation occurs when the humeral head does not stay in contact with the glenoid fossa. The classical presentation of this injury is in someone who falls onto his or her abducted or outstretched arm resulting in an antero-inferior dislocation. The athlete usually has severe pain and is unable to use or move the arm. There can be deformity seen at the shoulder. The shoulder often stays dislocated (especially first time dislocations) and must be reduced in an emergency or operating room setting by a physician skilled at orthopedic reductions, as the risk of fracture or permanent neurological damage is high. The result of GH dislocation can be significant damage to the surrounding supportive structures (anterior capsule, rotator cuff and glenoid labrum) that can in turn lead to persistent shoulder instability and pain. It is important to involve an orthopedic or sport medicine physician in the ongoing care to avoid and monitor for complications. Surgery is not uncommonly required at some stage in the management of this injury. The risk of re-injury (chronic dislocation) is greater the younger the patient at the time of first dislocation. Almost all athletes will sustain a re-dislocation if the initial injury occurs before age 18 and this can lead to the complication of recurrent shoulder dislocation and instability. At the other extreme, in the “mature athlete”, fractures, rotator cuff tears and shoulder stiffness are more likely to occur after GH dislocations. Physiotherapy becomes key in the treatment of all shoulder injuries regardless of whether surgery is performed or not. Shoulder stabilizing braces have a limited place in the prevention of re-injury in some athletes depending upon the sport.


Acromioclavicular Sprain – STEVE
Virtually any hockey player has either seen or had a shoulder separation – the disruption of the ligaments (acromioclavicular and coracoclavicular) that anchor the distal (outer) clavicle (collar bone) to the part of the scapula (shoulder blade) known as the acromion process. The classical mechanism of injury is a fall into the boards striking the top of the shoulder with the arm adducted or at the side. The clavicle anchors the shoulder girdle to the sternum (breast bone) and the force generated can cause the clavicle to fracture (more common in children) or separate from the acromion (“shoulder separation” – more common in adults and youth). The injury causes varying amounts of pain, disability and deformity depending upon the severity. Maximal pain and tenderness is found directly over the AC joint. A thorough assessment by a skilled professional, sling and ice are the most important first steps in treatment. Although surgery was a common way of treating more significant AC injuries in the past, most are now treated conservatively (with the use of slings, ice, pain control and physiotherapy) as the long-term function and prognosis is usually excellent no matter what the treatment. The most common complication is a slight deformity at the distal (outer) clavicle which has no bearing on function and which most athletes would prefer over a surgical scar. Degenerative changes can also take place in the AC joint over time leading to pain with horizontal cross adduction of the shoulder (reaching across the body). Usually only the most severe AC injuries require surgery.

Take care of your shoulder injury and make a friend for life.seperation