What is Shoulder instability?
Shoulder joint is ball and socket synovial joint formed between Glenoid (shoulder blade) and humerus (upper arm). It is most mobile joint of the body, which makes it inherently unstable. The socket (Glenoid) is quite shallow and covers only a third of the ball (Humerus). The glenoid labrum (fibro-cartilaginous structure) attaches to the periphery of the socket to deepen the socket and makes the joint more stable. The labrum besides increasing the contact area between the ball and socket, also produces a suction effect, maintaining intra-articular negative pressure and stabilises the joint. The joint is supported on all sides with ligaments, capsule and muscles.
Shoulder instability is a condition of the shoulder which is characterized by the inability of the structures surrounding the shoulder to maintain the head of the humerus (upper arm) within the glenoid cavity (the socket of the shoulder blade). In this condition, the shoulder joint becomes loose and the head of the upper arm (ball) is repeatedly displaced out of the cup (glenoid). This happens mostly in young athletes or aged people after 50 years. The main cause of shoulder instability is shoulder dislocations or shoulder subluxation (partial dislocation of the bones in the shoulder joint) due to falling on an outstretched hand, injury or trauma to the shoulder, overuse of arms in overhead sports like baseball, volleyball, softball, weightlifting or swimming, and loose ligaments of shoulder.
Shoulder instability is one of the most common conditions among shoulder joint ailments. The instability of shoulder can happen in one direction, such anterior (in the front), posterior (in the back) or in more than one direction (it is also known as multidirectional instability). Anterior instability is the commonest happening in 80-90 % of cases of shoulder instability.
What are the symptoms of Shoulder instability?
Its symptoms include pain, apprehension and weakness of shoulder in the affected site. There is loss of normal function and in some cases deformity can be seen. The patient also feels popping or grinding sound with specific movements.
How is it diagnosed?
Your physician can diagnose instability of shoulder by evaluating your complete medical history, physical examination and by ordering an X-ray. The exact reason for instability can be detected by MRI scan and CT arthrogram may be needed in certain cases to find out the extent of the damage to bones and surrounding structures.
What happens if nothing is done?
If it is left untreated, patient presents with worsening of function, persistent pain, weakness and increase in loss of movements. Neglected cases can lead to damage to cartilage and early arthritis.
How is it treated?
The treatment is focused on strengthening of the shoulder, control of pain and stabilization of the shoulder joint. The treatment is started with conservative methods such as activity modification, rest, medications and physiotherapy.
Surgery is indicated in
- High demand athletes
- Loss of bone of glenoid cavity (>20%)
- Recurrent dislocation or subluxation
Surgery is relatively contraindicated in multi-directional instability.
What are the non-operative treatments?
Non-operative methods or conservative methods are the first line of management in atraumatic instability and selected cases of traumatic instability. The aim is to restore the lost strength and stability and regain full range of motion. It includes the following –
- Medications- painkillers like paracetamol and codeine are given to control pain. Anti-inflammatory medicines like aspirin and ibuprofen are given to control inflammation.
- Physical therapy– physical therapy is designed for each patient based on the direction of instability, severity of symptoms and associated pathology in bone, labrum and muscles.
- The exercises are focussed on postural education, controlling and strengthening of rotator cuff, scapular stabilisers and deltoid muscles. Besides stretching of tight capsule/muscles and manual therapy concentrating on the movements in the glenohumeral, acromioclavicular, sternoclavicular joints and cervico-thoracic spine.
What does the operation involve?
The main purpose of surgery is to repair and tighten the stretched or torn ligaments of the shoulder to keep the shoulder joint in its position and improve the function of the joint. Shoulder stabilization surgery prevents recurrent instability. The surgery is performed under general anaesthetic as a day case. Majority of the patients have keyhole surgery (Arthroscopic), however few with complex injuries need open surgery.
- Bankart repair: The torn anterior inferior labrum along with the capsule is attached to the socket with the help of bone anchors.
- Remplissage: If the Hill Sachs lesion engage with the socket on external rotation of the shoulder, the rotator cuff tendons could be attached to the socket to prevent engaging. Though the patients have stable shoulder, they could lose some movements. This procedure is needed only in selective patients.
- Bristow – Latarjet procedure: This is performed in patients with bone loss from the socket and failed/recurrence after Bankart procedure. The procedure involves removing a part of shoulder blade (coracoid process) and attach that to socket to increase the depth and radius of the socket. This will prevent the ball from slipping out of cup. Muscles attached to the transferred bone provides additional stability.
- The Skin is closed using absorbable sutures. The operation takes usually 1-2 hours (depending of the complexity of the condition) and the majority of the patients are discharged on the same day after 4-10 hours after operation.
What happens after surgery?
- The effect of local anaesthesia ends in 4- 10 hours after surgery. The patients are encouraged to take painkillers before they can experience pain usually for 48 hours. In this way, many patients do not report pain.
- The patient is discharged on the same day and advised to take rest and modify his activities like avoiding overhead activities. A shoulder sling is applied for 6 weeks to support healing by immobilisation.
- Before discharge, the patient is taught set of gentle exercises of the shoulder. These exercises can be started from the day one after the surgery. These exercises are important to reduce stiffness and pain and restore strength and normal range of motion of the shoulder and arm.
- Light activities like using a keyboard or writing are allowed if they don’t cause excessive pain or discomfort.
- The patient is reviewed again after 2 weeks for the check of wound and physiotherapy.
- The wound should be massaged (typically after 2 weeks) using moisturising cream by the patient 3 times a day for 3 months once the wound is well healed. This reduces the scar sensitivity and scar-related complications (tenderness; helps scar to mature).
- Physical therapy plays an important role in returning back to the normal activities and its vital to work with the physiotherapists to get full function back in your shoulder. This variable in different types of instability, please discuss with your surgeon.
Are there any risks?
- Damage to nerves, blood vessels and tendons
- Axillary nerve injury
- Subscapularis injury
- Over tightening
- Late arthritis
- Frozen shoulder
- Hardware complications
- Graft lysis
- Stiffness and frozen shoulder.
What are the results of the operation?
The result of the operation is excellent in selected cases with a reduction of pain and stable shoulder. However, recovery time is different for each individual. The outcome is more predictable in the author’s experience.
When can I return to driving and work?
Depending on your job, you can return to work in 2 weeks (desk job) to few months (manual labour) and start driving after 6 -10 weeks.. You can restart sports after 6 months. Full recovery may take several months depending on the age and health of the individual, clinical nature of the SLAP tears and surgical technique adopted. Your surgeon can guide you for this.
A) Normal labrum
B) Complex labro-ligamentous (Bankart) tear and Hill Sach’s lesion
C) Bony Bankart lesion