Shoulder Problems

Last Updated on Thursday, 21 July 2011 14:44 Written by Administrator Friday, 18 February 2011 10:36

Shoulder Pathology

- according to Dr Stephen J O'Brien MD, MBA (2011), the O'Brien's test is 88% positive for an incarcerated long head of biceps tendon and only 54% have a labral tear, whereas the Subscapularis is usually normal in 300 cases.

- 63.6% of people under 40 will complain of fatigue discomfort, whereas 42.1% between the ages of 40 and 60 will complain of this when dealing with an 'incarcerated biceps'.

- "3 Pack" examination

"extra-articular" - direct palpation of bicipital groove

- throwing test

"Intra-articular" - active compression test

- 90 abd ER isometric test - palpate biceps tendon in bicipital groove if pain anterior it's a tendon problem, if the pain is posterior then it is likely to be internal impingement

- tightness of the posterior capsule will cause the head of the humerus to migrate superiorly during abduction and external rotation resulting in subacromial impingement. Subacromial impingement is where the bursa and rotator cuff impinge between the humeral head and acromion. Frequently have pain at night. Hawkins test can be preformed with isometric internal and external rotation to  confirm a 'working hypothesis' of subacromial issues. MRI  can further add diagnostic weight if not all of the three clinical signs are present

- rotator cuff tears (R.C.T) increase in frequency with aging (20% in 30-39 year olds, 60% in 60-69 year olds and 80% in 70-79 year olds) (Julie R Walton PhD 2011). Young tendon fribroblasts have a progressive collagen cross-linked matrix. There is very little renewal of collagen after 30 years of age. Tendon trauma results in the induction of protein kinases resulting in cell apoptosis (programmed death). This can be seen around small blood vessel proliferation. Hypoxia induces type III collagen production which appears to be driven by immune inflammatory cytokinase markers such as IL I, IL6, IL8, MCP-1. This process has been referred to as a "Collagen Switch" (George Murrell 2011). Additionally, there seem to be some markers associated with lipid metabolism which drive degenerative tendonopathy, suggesting people who are over-weight or who have metabolic syndrom may be more susceptible to tendonopathy

- the supraspinatus muscle architecture means that the tendon is more likely to degenrate on the subsurface i.e. adjacent to the head of humerus. Mid substance and superior degeneration can also occur but less frequently.

- three predictive tests for R.C.T's are supraspinatus weakness, weakness in external rotation, impingement pain in external rotation and/or internal rotation. Full thickness tears of <2cm2 are considered small, 2-4cm2 large and >4cm2 are 'massive and irreparable' (Prof George Murrell 2011). 

- shoulder instability can occur when the intra articular pressure of -40cmH2O (ie the vacuum) is disturbed. Clinically, they present with increased strength of the external rotators over the internal rotators (normally ER strength is 60% of IR, whereas with anterior instability the ER strength is 85% of IR strength) (Eiji Itoi, MD, PhD Sendei, Japan 2011). In 0 degrees the Superior Glenohumeral ligament acts as a stabiliser, at 45 degrees abduction it is the Mid GHL and at 90 degrees the inferior IGHL. The latter acts as a hammock for the humerus. For this reason proprioceptive isometric stabilisation exercises of the subscapularis and infraspinatus with the arm resting on table at 90 degrees abduction is considered important in the rehabilitation of the throwing arm.  Remember the rotator cuff muscles blend with the ligaments except at the foramen of Weitbrecht. Even at 45 degrees abduction O'Brien considers the Ant IGHL as the primary restrainer.

- Frozen shoulders also known as adhesive capsulitis are frequently of unknown aetiology. However, people with diabetes or hyperlipidemia have an increased tendency towards frozen shoulders due to the effect on the blood vessels of the suprascapula nerve as well as the direct effect on tendon metabolism. Immune compromise in for example people with severe neutropenia are also more susceptible to frozen shoulder. Post traumatic inflammation is also a potential contender to set the scene for a frozen shoulder. Moreover, there frequently appears to be a familial tendency in it's aetiology. People with Dyputrens contractures tend to have more severe problems. The severe acute painful stage can last from 6 weeks to 6 months. The 'cold' frozen stage can last up to 18 months. Cortisone can in some cases help with pain in the acute phase. Hydrodilation is sometimes used in the 'cold' frozen stage. People frequently find a lot of comfort using a hot pack in the arm pit. High doses of fish oil using 3000mg of EPA/DHA have been advocated. Physiotherapy includes a multimodal approach such as dry needling, laser therapy, soft tissue massage, joint mobilisations of the shoulder, ribcage, spine and a series of exercises.

Joint stability in the shoulder

- biomechanics and gamma reflexes

	Joint stability is determined by the muscular stiffness in 'soft' joints such as the neck knee and shoulder. Muscular tension generates stability at the glenohumeral jnt the outward curves represent the stabilising influence when the prime mover muscles act on the shoulder
	To enable stability at the glenohumeral joint during arm elevation  the scapula muscles position the glenoid to provide  optimal orientation  for the rotator cuff stabilising function
If the rotator cuff and scapular muscles do not operate synergistically then the potential for glenohumeral subluxation & subacromial impingement is generated

Summary

• the rotator cuff muscles provide glenohumeral stability
• the scapular muscles provide the positioning for inferior stability of the glenoid labrum for a snug fitting humeral head
• with the deep joint stabilizing muscles providing the stability, the prime movers may provide the 'action'
• generally speaking the stabilizing muscles of most joints are one joint muscles with an endurance function; whereas the prime movers are the muscles which lend power to the movement e.g. Pectoralis Major.  Therefore when designing an exercise regime the client must begin with good muscular stability before commencement of training of the prime movers.
• Frequently, clients compensate for lack of stability by increasing the speed at which they do the task.  This then leads to further in-coordination, poor timing between muscles, loss of synergy, and more dysfunction.
• Closed kinetic chain training to gain scapula and rotator cuff stability may encourage gamma afferent feedback from the annulospiral endings, as well as activate the nuclear bag and nuclear chain fibres
• Plyometric type exercises using theraband are designed to encourage eccentric-concentric control of the prime movers.

Plyometrics

EMG biofeedback

Interesting article

Commerford & Mottram (2001). Functional stability re-training: principles and strategies for managing mechanical dyfunction.  Manual Therapy, 6,1, 3-14

Commerford & Mottram (2001). Movement and stability dysfunction - contemporary developments.  Manual Therapy, 6,1, 15-26

• these articles are particularly interesting in respect to synergistic 'timing' of muscle action in the upper and lower limbs

Animated muscular synergistic interaction for shoulder abduction - refer to Climbing section

Shoulder Problems(English)

Schulter Probleme (Deutsch)

Last update : 22 July 2006