Shoulder instability: the management of a talented swimmer’s early injury problems

Anna, a tall, slim 15 year old, arrived for her appointment to see me with her mother. Together they explained that she had a national swim meet in a fortnight, but that her shoulders were really giving her problems – and had been doing so for about three months. During that time Anna had increased her training ahead of the state championships (at which she did surprisingly well in various freestyle and medley events, considering how little training she had done previously).

Anna seemed quite gangly, with stooping posture, a gait that looked very sloppy (knees hyper-extending and unstable pelvis) and quite big feet… it was as though she was designed for the pool!

She complained that her shoulders clicked, and occasionally felt like they ‘popped out of joint’ when she was doing a hard sprint session.

They tended to hurt mainly as an ache, often after she had cooled off, but occasionally during her warm-up. They could feel very tight when she woke up.

A GP they visited prescribed anti-inflammatory medication, told her she had rotator cuff tendinitis, and sent her for stretching and ultrasound treatment. In addition, the coach was keen to talk with me about what was going on with his star swimmer and whether she would be ready for the nationals in two weeks’ time!

Possible diagnoses

As soon as a clinician has been presented with the story of the injury, their brain begins to play with various diagnostic scenarios. This process, called ‘clinical reasoning’, weighs up the subjective (from interview) and objective (from hands-on testing or other investigative procedures) information gleaned and gradually develops an evidence-based rationale for the most likely diagnosis. The diagnosis forms the building block for all future management; hence: no accurate diagnosis, no good result!

In this instance, based on what we knew from Anna’s story, we needed to assess the validity of the following possible diagnoses, in order of greatest likelihood (there are other possible shoulder pathologies, but I believed these were the most likely):

Multi-directional instability (MDI) of the gleno-humeral joint

This was the strongest likelihood. The fact that Anna was having trouble in both shoulders implied a likely genetic/familial component and MDI tends to occur bilaterally in shoulders where there is a genetic tendency towards hyper-mobility. Excessive translation (shearing movement) and poor centring of the head of humerus (the ‘ball’ in the socket) in all directions leads to gradual destruction of the cartilaginous rim (the labrum) and rotator cuff tendon. Pain and clicking result, with the head of humerus in effect subluxing (repeatedly popping slightly in and out of the joint) during the swimming stroke.

Uni-directional instability of gleno-humeral joint

Excessively protracted posture (rounded shoulders destroy the swimmer!) can cause the centre of rotation of the head of humerus gradually to drift forwards. The subscapularis muscle loses its ability to control it, straining on the anterior-inferior capsule and labrum and creating anterior laxity, soon leading to instability.

Eventually the head of humerus would start to sublux over the anterior labrum, or the rotator cuff tendon would impinge under the acromion, resulting in pain and clicking. Uni-directional instability would be more likely to occur in one overloaded shoulder (especially on the non-dominant arm in a bilateral sport), not in two.

Posterior instability of the gleno-humeral joint was also a possibility, but much less likely, as swimming doesn’t seem to stress the posterior capsule.

Superior labrum anterior posterior (SLAP) lesion

Anterior laxity can also overload the long head of biceps tendon and anterior-inferior capsule which ends up destabilising the connection of the labrum to the bony glenoid. However, this type of shoulder injury more commonly afflicts throwing athletes and, again, usually presents unilaterally.

Rotator cuff impingement or tendinitis

Based on Anna’s account of her symptoms, this is likely to be a secondary problem caused by instability: uni- or multi-directional. In fact gleno-humeral instability is a much under-diagnosed cause of rotator cuff impingement or tendinitis. Anna, at the age of 15, is very unlikely to have tearing or significant degenerative change of her rotator cuff, although it and/or the sub-acromial bursa may be inflamed.

Clinical testing

Tests done by an experienced physiotherapist will greatly help to decide or confirm their hypothesis. We used the following tests to help us work out which of the above diagnoses best described Anna’s problem.

Sulcus test (gently drawing the head of humerus out of the socket) determines the extent of MDI and loss of normal negative-suction joint pressure, and compares left/right levels of laxity. We did other general hypermobility testing (eg, elbows and thumbs) to confirm Anna’s hypermobile status (which is shared by 10 to 20% of the population).

Anterior laxity testing: this is especially helpful at 90 degrees and abduction with full external rotation, to test the laxity of the anterior-inferior gleno-humeral ligament. You can test up to 140 degrees abduction to approximate the ‘catch position’ of the freestyle stroke. This test will determine how far the head of humerus passively migrates anteriorly in the glenoid; the results are graded I to III, depending on the distance it moves relative to the width of the head of humerus. You would also do anterior-posterior glides of the head of humerus in sitting, to help work out the direction and extent of laxity.

Apprehension testing: also for anterior instability, the test is positive if a posterior glide of the head of humerus in a ‘stop’ sign takes away discomfort.

Posterior laxity testing: determines the extent of instability in the context of MDI.

Long head of biceps: test by resisted elbow flexion or forearm supination, loading in various positions eg, during internal/external rotation at 0-45 degrees abduction, or in the swimmer’s catch position or pullthrough phase. Clicking and pain might reveal the compromised integrity of the labral attachment.

Impingement: the tests are active (eg, the ‘empty can’ test) and passive (internal rotation in horizontal flexion) to allow you to note whether pain is primarily from instability or tightness.

Flexibility of rotator cuff: at 90 degrees abduction, internal rotation should be at least 60 to 70 degrees while stabilising the scapula.

Stability testing:

a. Can the athlete hold the head of humerus posteriorly in the socket with internal rotation pressure, especially at 90 degrees abduction? This tests subscapularis control.

b. Resisted internal rotation in various angles of abduction/flexion will enable you to note the athlete’s awareness of scapular position and tonic muscular holding capacity.

c. Use the push-up facing a wall or plank position to test serratus anterior: note winging and loss of scapula and/or trunk control.

Cervical and thoracic spine: Palpation will help you assess hypomobility. Stiffness here is very common and disrupts the normal movement of the gleno-humeral joint by preventing the scapula from upwardly rotating, or by affecting neural mechanics.

Short-term (pre-competition) aims of management

Having done the above tests we concluded that Anna’s main problem was a multi-directional instability of the gleno-humeral joint, rooted in being genetically hyper-mobile. This had led to secondary irritation and impingement of the rotator cuff tendon.

Once we were fairly certain of our diagnosis, we devised a management plan, initially focused on the big upcoming competition; thereafter looking to provide a long-term resolution of Anna’s injuries. Trying to be realistic about what we could achieve in two weeks, we limited our pre-competition strategy to three areas:

1. Establish accurate diagnosis as early as possible This was essential. It might require a second opinion from a sports physician, and possibly scans: ultrasound for rotator cuff tendon integrity, CT arthrogram/MRI for labral tears, X-ray to view shallowness of the glenoid socket.
2. Minimise pain leading up to and including race period and recovery, and minimise further joint breakdown We used trigger-point work and massage on the rotator cuff to eliminate pain from active movements, impingement positions and finally, her swimming stroke.

We undertook deep-tissue massage of lats, pecs, biceps, neck and inter-scapular muscles.

We mobilised the thoracic and cervical spine.

We immediately stopped Anna from continuing any harmful or aggravating practices, such as bad sleeping positions (with her shoulders at end-of-range positions and being leant on badly), carrying too heavy a school back-pack, any risk from other sports she might be playing.

We assessed Anna’s stretching regime, believing it was likely that most of her stretches would be damaging her because of her poor control. As a better alternative we taught her self-triggering and massage.

We taped the scapula for support out of the pool and to help Anna reeducate her posture. In the pool we experimented with non-rigid tape for joint support and scapular proprioception.

We discussed with Anna’s coach a short-term reduction in her training load (even more than her planned tapering programme) and intensity for pain management, and established a focus on quality not quantity during the run-up to the competition (for instance, minimising her butterfly training because of the greater loads this stroke places on the anterior joint structures).

We used non-steroidal antiinflammatories and ice after training as required.

3. Educate Anna, her parents and her coach. The key points to convey were:

• the nature of the shoulder problem, especially how normal and unstable shoulders differ structurally;
• the importance of posture;
• an overall appreciation of the strengths and weaknesses of her body-type: her flexibility, which had been such a plus in her swimming, needed to be balanced by stability and strength. Muscle control and strength must become her focus or she would never establish herself as a competitive swimmer. She needed a paradigm shift from concentrating mainly on flexibility to focusing instead on technique, coordination, warm-up drills and home-based self-massage and triggering to deal with tightness.

Her long-term goal had to be prevention and management. She would have to learn to stay on top of it by doing positive things for her shoulders, especially when they were feeling good.

Long-term (post-competition) aims of management

It is predicted (and hoped) that a full resolution of Anna’s shoulder problem is possible, with a return to symptom-free swimming and a full training and competitive load. She would likely, however, need to maintain a preventative regime to ensure she stayed injury-free. As with many athletes who have had sports injuries, Anna will have to get used to taking responsibility for preventing a recurrence until the day she decides to hang up her goggles for good.

We had three main long-term strategic goals.

1. Maximise the muscular control of her passively unstable glenohumeral joint

This involves developing, with Anna, her parents and her coach, a graduated plan to combat weaknesses and active instability.

The retraining work should start with local stability muscles, initially isolating and then working synergistically around three key areas:

• trunk (transversus abdominis)
• scapula (lower trapezius and serratus anterior)
• head of humerus (subscapularis).

The activation of these tonic stability muscles is a fairly precise clinical science that may require ultrasound, EMG, pressure biofeedback or palpation skills for effective learning.

This stability and strengthening work would take three to six months, divided into three phases: Activation of correct muscles, as described above. For instance, if Anna didn’t learn to activate her scapular control muscles, she would perpetually tend towards downward rotation, making it impossible for her subscapularis to control the head of humerus properly. So the mid-lower traps (upward rotators of the scapula) must be trained over the rhomboids for stability. See exercise 1.)

Recruitment of same stability muscles into rehab and dry-land swimming drills. The exercises should gradually stress global strength and stability muscles as local stability improves. The quality of control remains a high priority as the exercises are progressed. (See exercises 2a-2c.)

Training – stability and strength gains on land would be incorporated into gradually increasing intensity and distance in the pool. As long as Anna’s shoulders are asymptomatic after a few months of rehab training, her swimming training and competition schedule should not need to be affected. Pool drills will further develop her awareness and endurance. During warm-up, Anna should do low-load stability drills rather than stretching to activate the brain-body connection.

Regardless of whether the shoulders are symptomatic, the off-season will need to include a few weeks of stability and strength work in the lead up to the beginning of swim training.

2. Resolve technique issues and do video analysis

This would be introduced through all three phases of rehabilitation training, in close liaison with the coach. It is critical that an athlete’s learning and awareness of good stability runs alongside their correction of poor technique, so they can understand and apply the muscle retraining to make necessary but often subtle changes to movement mechanics. For instance, learning to hold the trunk and shoulders still while ‘catching’ the water and pulling through directly enhances scapular stability.

3. Long-term flexibility management

For Anna, the priorities would be her thoracic spine, latissimus dorsi, pec and neck musculature, to enhance the stability of her trunk, scapula and head of humerus. She would be likely to need maintenance physio and massage, especially in periods of intense training and competition, in order to remain symptom-free. If she can overcome the obstacles at this stage of her career, she could open up for herself the opportunity to achieve what the shoulders of Ian Thorpe have: genetic hyper-flexibility coupled with fantastic control and strength, leading to top-level success.