| nstability of the shoulder in multiple directions is | | | | we want to within our visual fields, enabling us to |
| moderately often encountered, occurring normally on | | | | perform actions while we watch. We have sacrificed |
| both sides of the body and is not related to accident | | | | stability of this joint for its mobility, leading to |
| or injury. The underlying difficulty is the laxity of the | | | | consequent problems when the shoulder is stresses in |
| capsule of the shoulder and the deficiencies of these | | | | various ways. |
| stabilising ligamentous structures. This ligament laxity | | | | Thinking about the stability of the shoulder it is helpful to |
| shows itself in excessive joint mobility in all anatomical | | | | concentrate on a few concepts. The idea of balance |
| directions. Patients may describe joint instability as the | | | | is related to the way the head of the humerus centres |
| shoulder may sublux (partial dislocation) or wholly | | | | itself on the socket accurately. The main muscles |
| dislocate from time to time. However, the patient may | | | | responsible for maintaining this anatomical alignment |
| not suffer such obvious symptoms and complain only | | | | are those of the rotator cuff, keeping the joint in line as |
| of pain. | | | | the larger movement muscles do their actions. If an |
| Conservative treatment is the first line of management | | | | imbalance or weakness develops in the muscles of |
| for this condition, with physiotherapy treatment | | | | the scapula or the rotator cuff then the balance can |
| consisting of strengthening of the muscular parts of | | | | be disturbed. A cartilage rim around the socket, the |
| the scapular stability and rotator cuff systems. Once | | | | glenoid labrum, deepens the socket and the muscles |
| conservative treatment has been attempted and not | | | | compress the two parts together, enhancing stability. |
| been successful then consideration can be given to | | | | The upper part of the glenoid cavity helps to combine |
| surgery. Surgery can tighten up the shoulder capsule, | | | | with the compressive force of the rotator cuff to |
| increasing the strength of the static stabilisers. Typically | | | | resist an upwards movement of the humeral head on |
| surgery has been done in open technique but | | | | the socket. The joint surfaces are moist with synovial |
| arthroscopic technique is become more prevalent. | | | | fluid and have a tendency to stick together to some |
| The incidence of this instability problem in the general | | | | degree, with the depth of the socket combining with |
| public is not obvious and shoulder instability from | | | | the convexity of the ball to squeeze out any air from |
| accidents is much more common as a secondary | | | | between them and so form a suction force keeping |
| effect from shoulder dislocation. The shoulder instability | | | | the joint together. The slight negative pressure in a tight |
| types are classified in various ways and TUBS stands | | | | joint adds to this effect. All these effects allow an |
| for: | | | | increase in stability in the middle ranges of the |
| * Trauma involved in the cause | | | | movement of the joint, the part of the movement |
| * Unidirectional instability (only unstable in one direction) | | | | where the ligamentous restraints are slacker. |
| * Bankart lesion (damage to the rim around the | | | | The main passive constraints to excessive movement |
| shoulder socket) | | | | of the shoulder joint are the capsule and ligaments. |
| * Surgery - is a common requirement | | | | The ligaments are thickened parts of the capsule |
| A single or repetitive dislocation of a shoulder joint | | | | designed to contain shoulder movements within |
| traumatically can lead to the generalised instability | | | | sensible and safe limits, the most important ligament |
| problem described in TUBS. | | | | being the inferior glenohumeral ligament. The |
| The multidirectional type of shoulder dislocation is | | | | importance of the dynamic parts of the stability picture |
| summarised by AMBRI, standing for: | | | | must not be ignored and physiotherapists concentrate |
| * Atraumatic cause - no injury or accident | | | | on these muscles, attempting to re-educate and |
| * Multidirectional - the shoulder is lax in all directions | | | | strengthen the scapular stabilisers and rotator cuff |
| * Bilateral - both shoulders are always involved due to | | | | muscles. |
| general laxity | | | | Jonathan Blood Smyth is the Superintendent of |
| * Rehabilitation - this is the initial treatment process | | | | Physiotherapy at an NHS hospital in the South-West |
| * I refers to the technical types of surgery and where | | | | of the UK. He writes articles about back pain, neck |
| they are performed. | | | | pain, and injury management. If you are looking for |
| The shoulder joint has a very high degree of mobility | | | | physiotherapists in Sheffield visit his website. |
| and is designed to allow us to place our hands where | | | | |