Impingement (painful arc) syndrome
What is Impingement syndrome?
Impingement syndrome is a condition of the shoulder where the tendons and bursa around the shoulder get inflamed. It encompasses wide range of pathologies in the subacromial joint, encompassing rotator cuff tendinopathy, subacromial bursitis, calcific tendinitis etc. In this condition, the space between rotator cuff tendons and acromion (top of shoulder) reduces, leading to compression of structures underneath acromion (rotator cuff and bursa) with overhead activities.
This condition is also known as rotator tendinitis or swimmer’s shoulder or tennis shoulder. A rotator cuff is a group of four muscles that are critical in the movement and stability of the shoulder joint. It comprises of supraspinatus, infraspinatus, teres minor and subscapularis, that connect the head of the humerus to the shoulder blade. Its main function is to attach the arm bone firmly with the shoulder blade. It essential for lifting and rotating the arm and keeps the arm firmly in the socket of the shoulder.
It develops due to repeated injury or overuse of shoulder as done in sports like swimming, tennis, baseball, etc, or in professions like painting, construction work, etc. or due to wear and tear in old age. It happens usually in individuals who perform repeated overhead physical activities. Rotator cuff tendinitis is the third common muscular complaint in all shoulder conditions. This condition is common in people above 60 years and the incidence of this condition rise with an increase in age. 16 to 30 % of cases of impingement syndrome affect younger people in 3rd or 4th decade, due to sports or occupational injuries.
What are the symptoms of Impingement syndrome?
This condition may have a sudden or gradual onset. The pain is located at the top of the shoulder that radiates along the outside upper arm and in some cases down to the hand. Pain can be felt during activity or even in rest or at night, especially when lying on the affected side. Elevation of the arm is difficult, and the pain usually felt in the middle part of arc of motion. Weakness in the affected arm is also common. As the condition progresses, you will lose your strength and range of motion, and feel pain at night that wakes you up from sleep. Even simple work like zipping or buttoning becomes difficult.
How is it diagnosed?
The diagnosis is made on the basis of your medical history, physical examination, and X-ray. X-Ray is usually performed to check a spur (bony projection), and other shoulder conditions. MRI scan or ultrasound may be done to check the involvement of the soft tissues and the extent of damage to the rotator cuff.
What happens if nothing is done?
If it is left untreated, the inflammation could damage the rotator cuff tendons and may lead to rotator cuff tear. Persistent impingement syndrome affects daily activities especially lifting the arm.
How is it treated?
The treatment is focused on the reduction of the pain and restoration of the normal function of the shoulder. It totally depends on the activity level, age, and profession, general health of the individual and severity of the case. Treatment can be done conservatively or surgically. Majority of the patients get better with conservative treatment, which involves rest, application of ice, medications, steroid injections and physiotherapy.
Surgery is indicated in
- Failure of conservative treatment
- Partial rotator cuff tear (>50% thickness)
- Full thickness rotator cuff tear
- Impingement secondary to glenohumeral arthritis, Shoulder instability
What are the non-operative treatments?
Non-operative treatment is indicated in most of the cases. Night pain contradicts non-operative treatment. Conservative or non-operative treatment includes
- Rest– your surgeon will advise you to take proper rest and avoid any activity that provokes pain such overhead activities. Activity modification can reduce repeated injury to the tendon.
- Application of ice – you can apply ice twice or thrice in a day for 20 minutes on the affected area to manage pain.
- Medications- painkillers like paracetamol are prescribed to relieve pain. Anti-inflammatory medicines like ibuprofen or aspirin are given to reduce swelling and pain.
- Physical therapy- physical exercises are necessary to ease the pain and strengthen the muscles. These exercises are programmed to strengthen the shoulder blade and rotator cuff muscles. The exercises begin with the gentle range of motion and slowly progressing to strenuous exercises under the supervision of a physiotherapist.
- Steroid injections- if all the above methods fail, your surgeon will give you steroid injections. Cortisone (an anti-inflammatory medicine) is directly injected into the bursa below the acromion to relieve swelling and pain. Its effect could be temporary and physical exercises should be continued with it to gain fruitful results. More than three injections are not recommended as it may damage the tendon.
What does the operation involve?
The main aim of surgery is to remove the inflamed part of the bursa, remove the bone hook (part of acromion) and create sufficient space for the rotator cuff to glide without impinging on the surrounding structures. Subacromial decompression is usually performed arthroscopically.
Surgery is usually performed as a day case under general anaesthetic; an incision is made in the skin over the affected site.
- The author usually performs the surgery using keyhole surgery (arthroscope) as a day case under regional/general anaesthesia. , 2-3 small 1cm cuts are made around your shoulder and a tiny camera (arthroscope) and shavers are inserted through the cut and spurs (bony projections) or inflamed part (bursa) is excised from the acromion to make space for the rotator cuff to move freely.
- The skin is stitched using absorbable sutures and a sling is applied for two to four weeks. The surgical time is usually 1-2hrs and the majority of the patients go home the same day.
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 based on the procedure. A sling is applied for 2 to 4 weeks to support healing.
- 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. Besides gentle range of movement exercises are started as tolerated by the patients without restrictions.
- 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 the moisturizing 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 is advised to ensure rehabilitation. Following subacromial decompression, patients are allowed to mobilise as tolerated without restrictions. Your physiotherapists and surgeon will guide you for the choice and duration of the exercises. The exercises are designed in such a way that you can regain the range of motion of the shoulder with the strength of the arm and also improve posture.
Are there any risks?
- Damage to the nerves, vessels or tendons
- Persistent shoulder pain, weakness and stiffness
- Axillary nerve injury
- Frozen shoulder
- Injury to acromioclavicular joint
- Adhesive capsulitis (rare)
- Deltoid detachment in open surgery
What are the results of the operation?
The success rate of surgery is > 95% with fast recovery and minimal complications. However, the results depend on the age of the patient, his profession, duration, the extent of damage of the muscles and surgery performed. The outcome is more predictable in the author’s experience.
When can I return to driving and work?
You can get back to work in 2-4 weeks if you have a desk job, however might take a little bit longer if your job involves physical work. You should be able to resume driving in 2-4 weeks. The above time line could vary based on the severity of problem and the treatment modality. Your physician will be able to advise you.
The bursa underneath the acromion (Red) could be inflamed because of impingement or due to rotator cuff tendinopathy or vice versa.
The hooked or curved acromion could predispose shoulders to impingement syndrome