SHOULDER INJURIES

Shoulder joint injuries can develop either acutely (e.g. a sudden fall) or chronically (e.g repetitive strain). On this page I am going to be concentrating on the common acute problems that affect the shoulder joint as a result of snow sports accidents. This is not meant to be an in-depth appraisal of orthopaedic treatments, but a simplified description of injuries and treatment. For more general information on the shoulder joint itself, try the American Academy of Orthopaedic Surgeons webpage - here.

Not surprisingly, the two commonest mechanisms leading to shoulder injuries on the slopes are falls and collisions.

Falls can injure the shoulder in one of three ways -

  1. The casualty falls directly onto the shoulder joint itself
  2. In the process of a fall, the casualty lands onto an outstretched hand and the force of the fall is transmitted up the arm to the shoulder
  3. The casualty again falls onto an outstretched hand, but also in the event of the fall the casualty's body twists around the outstretched hand which applies a twisting force up to the shoulder joint

In common with all other snow sports injuries, its the mechanism of the injury, coupled to the force(s) involved and the time frame over which they are applied, that dictates the type and severity of the resultant injury.
 

Shoulder anatomy


 

Statistics for shoulder injuries from snow sports

In Scotland, shoulder injuries account for about 10% of all alpine ski injuries, 15% of all snowboard injuries and about 5% of all skiboard injuries. The breakdown of shoulder injury type by snow sport (taken from our injury database in Scotland) is illustrated below . Joint injury includes dislocations and subluxations of the shoulder and AC joint.

       

Bissell et al (reporting results from the ongoing Vermont study in the USA) published a paper in the American Journal of Sports Medicine in July 2008 specifically looking at shoulder injuries from snow sports. They found the incidence of humerus fractures among snowboarders (0.062 per 1000 snowboarder days) to be significantly higher than that of skiers (0.041 per 1000, P < .05). Skiers were more likely to sustain proximal fractures, and snowboarders were relatively more likely to sustain diaphyseal and distal fractures (P < .05). When looking at acute shoulder dislocations, 6.56% were associated with proximal humerus fractures among skiers (compared to 1.7% among snowboarders). Snowboarders who lead with their left foot were more likely to fracture their left humerus (P = .023). Helmet use and gender were not risk factors for humerus fractures among either skiers or snowboarders. Jumping was involved in 28.3% of humerus fractures among snowboarders and in 5.4% among skiers. Skiers with humerus fractures were more skilled, older, and fell less frequently than controls. Snowboarders were less skilled, younger, and fell at a similar rate compared with controls.

Ref. Bissell BT et al. Epidemiology and Risk Factors of Humerus Fractures Among Skiers and Snowboarders. Am J Sports Med. 2008 Oct;36(10):1880-8. Epub 2008 Jul 1


Shoulder dislocations
An acute dislocation of the shoulder is an extremely painful injury. It usually occurs as a result of a fall onto an outstretched hand, with the momentum of the fall twisting the body round and wrenching the shoulder out of joint (even the description sounds painful!). The end result is that the bulb-shaped head of the humerus bone (the upper arm bone) is pulled out of its normal alignment within the shoulder joint. In the majority of cases, it comes to lie in front of and below its normal position - this is called an anterior dislocation (see left). More rarely, the shoulder may dislocate in a backwards direction [posterior dislocation]. These can be trickier to diagnose and require additional x-ray views!

A paper in 2011 by Ogawa and colleagues (Injury, in press, 2011) reported the overall rate of shoulder dislocation to be 0.0583 per 1000 participant days. The risk is higher in snowboarders (0.0676 per 1000 participant days) than skiers (0.0295 per 1000 participant days). Shoulder dislocations in snowboarding were significantly more common in older participants, males compared to females, wet snow conditions, injuries of the leading-side joint and engaging the toe-side edge of the snowboard. In skiers, dislocations were again significantly more common in older participants and males. Other risk factors included higher skill level, falls and injuries occurring on steep slopes. 95.8% of dislocations were anterior in nature and the prevalence of fracture-dislocations of the glenohumeral joint was higher in skiing (33.9%) than in snowboarding (12.4%).

The diagnosis of a dislocated shoulder is usually clinical - with experience, you can usually tell one as soon as they walk in the clinic door! Those with dislocated shoulders tend to walk slowly, being extremely careful to hold the affected arm to prevent any (extremely painful) movement in the arm. Their stance is often such that they tend to lean towards the affected side. On examination, the affected shoulder joint has lost its normal smooth curved shape and you can often feel a gap where the humeral head used to sit in the joint. You can see this "rounded off" shape in the picture on the . Individuals who have suffered recurrent dislocations - sometimes many of them - do not usually experience as much pain as those for whom it is their first incident.



Research evidence suggests that most dislocated shoulders do not need to be x-rayed before they are reduced (put back in place). We use Kocher's technique in Aviemore and can reduce about 90% of anterior dislocations either in the ski patrol room or in our clinic. My very last patient on New Year's Eve 2007 had a dislocated shoulder - very satisfying for both me and him when it clunked back into place! The sooner the reduction takes place the better. Sometimes, it is not possible for us to reduce the shoulder and the casualty is referred onto hospital for reduction to be performed under a general anaesthetic. This is usually as a result of one of the following scenarios -

  • Long delay before reduction is attempted (muscle spasm sets in)
  • Very muscular casualty (muscle spasm again + doctor needs to go on steroids to stand any chance!)
  • During the injury, part of the soft tissues of the shoulder joint have become trapped and prevent simple reduction. In this case, open reduction may be required


After reduction, the patient usually experiences sudden and satisfying relief of their pain. The evidence suggests that [in normal circumstances] the shoulder should be immobilised (in a sling or collar + cuff) for no more than three weeks before the shoulder can begin to be actively exercised - ideally under the supervision of a physiotherapist.

Unfortunately, once you have dislocated your shoulder once, there is something in the order of a 85% risk that the shoulder will re-dislocate at some point in the future - because the original structural integrity of the shoulder has been damaged and so the joint will never be as strong as it once was. Consequently, it usually takes less force to re-dislocate....so take care! Some good news is that a recurrently dislocating shoulder is usually not as painful as the first dislocation and also is usually easier for the attending doctor to put back into joint. There are several surgical procedures (such as the Bankhart repair) that can be performed on such shoulders to stabilise them.

Fractures of the collar bone (clavicle)

The collar bone (clavicle) is the most commonly fractured bone in the entire body! It is also the commonest fracture of the shoulder joint seen in both skiers and snowboarders and the commonest upper limb fracture in skiers (in snowboarders it comes second to the wrist). As a consequence, many people have seen collar bone fractures before and recognise them when they occur. They usually result from the transmission of force in a fall up the arm which is absorbed in the collar bone which finally breaks as a result. They are fairly easy to diagnose with localised pain at a specific site along the bone, usually accompanied by obvious swelling over the fracture site. The bone can be divided into three segments - inner, middle and outer. Fractures usually occur at the the weakest point of the bone, which is the junction of the middle and outer thirds.

Because its easy to diagnose, we don't usually take x-rays to confirm the diagnosis (..this helps prevent you all glowing in the dark). Sometimes x-rays are useful to differentiate between a fracture at the end of the collar bone or damage to the AC joint (more on this below).

Fortunately, most clavicular fractures heal up pretty quickly - normally a support in the shape of a collar+cuff or broad arm sling are worn to help reduce pain, but usually this subsides fairly rapidly and then the shoulder can be exercised. Old figure of eight bandages (that theoretically pull the shoulders back and were thought to help some clavicular fractures to heal) are now very much regarded as out of date. On rare occasions, one of the fragments of the broken bone may end up pressing hard against the skin above it - in these circumstances, surgery may be required to attach the two bits of bone together with surgical wire.

Generally though, you'd be very unlucky to be left with any form of functional deficit after a fractured clavicle, (i.e. you'll be able to do everything you need to with the arm) but you may always have a wee bump over the bone to remind you of the event....


Acromio-clavicular joint (ACJ) sprains

The AC joint sits between the outside end of the clavicle and the bit of the shoulder blade known as the acromion. A ligament connects the two and holds the joint together. A fall with direct impact on the outside of the upper arm may lead to this ligament being damaged and tearing, allowing the joint to distort (a so-called subluxation, also known in the game as a "sprung" AC joint) or become completely separated (a dislocation). Just to confuse you, both of these are also lumped in under the general term "sprain"!!

As with all ligament sprains, damage to the ACJ can be graded 1 to 3 depending on the degree of damage - the photo on the right shows an example of a grade 3 sprain and note the obvious difference in contour between the two shoulders - the accompanying x-ray is beside it. Click on either for the full size view. Sometimes it can be difficult to distinguish an ACJ sprain from a fracture of the very end of the clavicle. Careful (and gentle!) palpation though will usually reveal that the tenderness of an ACJ sprain is very localised to the joint whereas with a broken collar bone it is more spread out.

Grade 1 & 2 ACJ sprains can usually be treated conservatively with the arm in a collar + cuff and good analgesia. Most grade 3's can be treated in a similar manner but need careful follow-up - as with a collar bone injury usually there is good recovery of function in the shoulder -again with a prominent bump as a reminder. Exercising the shoulder to rehabilitate it should take place ideally under the expert guidance of a physiotherapist. If the shoulder is not settling, it's possible again that internal fixation of the shoulder joint may be required.
 

Fractures of the humerus

The humerus, as you can see from the diagrams on this page, is the upper arm bone connecting the shoulder with the elbow. There are three main types of fracture that we see from snow sports affecting this bone -

  • Fractures of the upper (top) end of the bone - these commonly affect the head and neck of the bone (the light bulb shaped bit)
  • Fractures of the shaft (middle) bit of the bone
  • Fractures at the elbow end of the bone - these are termed supra-condylar fractures (because they normally occur above [hence supra] the condyles [bony nobbles at the end] of the elbow. These are more likely to affect children than adults


The first two usually result from direct trauma to the humerus - i.e. a collision with an object or a heavy fall directly onto the bone. Shaft fractures in particular result when bending forces are applied [just like breaking a stick]. Supracondylar fractures are a result of uppers transmission of force once again as a result of a fall onto an outstretched hand - in a nutshell the elbow gets whammed into the lower humerus and the supracondylar area breaks (I love getting technical!)

   
Upper Humeral Fractures

These fractures are more likely to affect the neck of the bone (as in the picture left) - there are complicated classification systems but in essence what is important is whether the fracture is displaced and/or stable or not. Most stable fractures (even though the x-ray might look extremely impressive!) do not require anything more fancy than rest in a broad arm sling - the pull of the weight of the arm helps to keep things in the right place whilst the bone heals itself. Surgery is rarely required. Displaced fractures might require reduction (pulling) under anaesthetic to get the bone fragments to sit together.


Fractures of the Shaft of the Humerus


These injuries are usually pretty painful but again may not need surgery depending on the exact nature of the injury. It is usual to place the arm into some form of plaster cast to provide both additional weight to keep the arm pulled (keeping the bones in alignment) and protection for the injury. Sometimes these injuries can result in damage to the radial nerve and this should be checked for. Although conservative treatment is usually successful, there is a slight risk that the bones might not quite knit together in the right alignment - known as mild malunion.

Supracondylar fractures

These injuries are graded from 1-3 depending on the degree of displacement present. Grade 1 injuries are treated conservatively, the others require surgery - either closed reduction or open reduction and internal fixation. Fortunately, as most occur in children, the prognosis is usually excellent as children's bones (which are still growing) tend to heal well.


Rotator Cuff Injuries

The term "rotator cuff" refers to the 'cuff' of muscles and soft tissue that basically hold the shoulder together and allow for its range of movements. Not surprising then, that any sudden wrench of the shoulder joint in an accident can damage these structures leading to an injury known as a rotator cuff tear. Fortunately, many of these injuries, whilst initially painful and thus restrictive on shoulder movements, settle down pretty quickly and do not usually lead to longer term problems. Obviously, this will depend on the degree of damage done though. Tenderness is usually fairly localised as is the restriction in movement (if it is assessed carefully).

Treatment is along the usual lines of anti-inflammatories, early physiotherapy and mobilisation of the shoulder. The worst thing that can happen is to leave the shoulder in a sling for too long - this simply leads to the shoulder freezing which is a far worse condition. This may need aggressive physical treatment and/or a cortisone injection to sort it out - best avoided in the first place!


 

Shoulder rehabilitation after injury


Click here for our latest advice sheet on the do's and don't of managing shoulder injuries

As you will see I have stressed throughout this page, successful rehab after a shoulder injury ideally demands the input of a physiotherapist. Under their expert guidance, the shoulder joint can be mobilised and restored to full function with minimal risk of further damage. The following links suggest some of the exercises that are of benefit after shoulder injuries. They should really only be performed under the guidance of a physio or your own doctor.

Rotator cuff exercises
American Academy of Orthopedic Surgeons exercises
 

Useful websites


Wheeless' Textbook of Orthopaedics shoulder page [Fantastic & accurate information, albeit medical!]

Medline's guide to shoulder websites
     And one of the best links from there..

Top UK shoulder surgery unit in Reading, Berkshire

 


 



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