Shoulder conditions: Subacromial impingement syndrome

The shoulder is one of the most complex joints in the human body and also the most mobile. Made up of several joints, ligaments and tendons, the shoulder is a vulnerable area precisely because it includes so many different structures.

Subacromial impingement syndrome is one of the most common causes of shoulder pain in adults. It occurs when the upper part of the shoulder blade (the acromion) presses on the rotator cuff when the arm is raised. The rotator cuff groups together the tendons of four muscles: supraspinatus, infraspinatus, subscapularis and teres minor. These muscles cover the head of the humerus and work together to lift and rotate the arm at the shoulder.

• What is subacromial impingement syndrome
• Causes of subacromial impingement syndrome
• Symptoms of subacromial impingement syndrome
• Treatment methods
• Recovery after surgery

What is subacromial impingement syndrome?

The shoulder is made up of three bones: the upper arm bone (humerus), the shoulder blade (scapula) and the collarbone (clavicle). The upper part of the arm bone, the head of the humerus, fits into a socket in the shoulder blade. The combination of muscles and tendons that keeps the humerus attached to the trunk and centred in the socket of the shoulder blade is called the rotator cuff.

The acromion, the front edge of the scapula, sits above and in front of the humeral head. When there is not enough space between the acromion and the rotator cuff, the acromion rubs or presses on the surface of the rotator cuff as the arm is raised. This causes pain and limits movement. The rubbing of the acromion against the cuff is known as subacromial impingement.

The pain felt, often accompanied by restricted movement, can be caused by inflammation of the bursa that covers the rotator cuff, producing the condition known as bursitis.

The bursa is a "sac" containing a small amount of joint (synovial) fluid, whose role is to reduce friction in the regions where the skin, muscles, tendons and ligaments come into direct contact with the bones. The bursa can become inflamed as a result of overuse or injury. These are also the causes of inflammation of the rotator cuff tendons, which give the shoulder its mobility and stability. Inflammation of these tendons produces the condition known as tendinitis. In some cases, a partial tear of the cuff may be the cause of the impingement pain.

Causes of subacromial impingement syndrome

Subacromial impingement syndrome occurs frequently in people who engage in intense physical activity. Athletes who practise swimming, tennis, baseball, volleyball or other activities that involve repeatedly raising the arms above the head have a higher risk of developing subacromial impingement syndrome. Certain occupational groups, such as builders or painters, are exposed to the same risk. The condition can also appear after seemingly minor injuries, or spontaneously, without any apparent cause.

Symptoms of subacromial impingement syndrome

In the early stages of the condition, patients may feel mild or moderate pain, which does not seem worrying, although it is felt both during exertion and at rest. The orthopaedic surgeon is usually not consulted at this stage, even though doing so would greatly ease patients' suffering. If treatment is neglected, the symptoms will become acute. The pain will radiate from the front of the shoulder to the outer side of the arm and will occur with every lifting movement of the arm.

Let us imagine a tennis player who wants to serve on court and who, every time they raise their arm to hit the ball and then lower it, has to endure intense pain. Movement will become more and more limited, and the pain will then also appear at night. The arm will lose strength, and mobility can become so reduced that simple tasks (taking off a T-shirt, doing up a zip at the back) can only be completed with effort and pain. In advanced cases, the restriction of movement can progress to the condition known as "frozen shoulder".

Treatment methods

Whether the treatment is conservative or surgical, the aim is to reduce pain and inflammation and to restore the motor function of the shoulder. The orthopaedic surgeon will indicate which treatment is most suitable for the patient, taking into account their age, level of daily activity and the stage of the condition.

Conservative treatment

The initial treatment of subacromial impingement syndrome consists of:

• Rest and anti-inflammatory medication;
• Cortisone injections, for pain that persists even after taking anti-inflammatories. Cortisone is a powerful steroid that can be very effective in temporarily reducing inflammation and pain;
• Treatment can last up to six weeks and involves, in addition to exercise and massage, the use of heat or ice to reduce inflammation and relieve pain. Ultrasound therapy is also very useful.

Surgical treatment of subacromial impingement syndrome

If the pain persists after conservative treatment, the orthopaedic surgeon may decide on surgical treatment. This can be carried out in several ways.

Subacromial decompression

This is a minimally invasive surgical procedure that uses arthroscopic technique. The aim is to widen the space between the acromion and the rotator cuff tendons. Reducing the pressure on the subacromial tissues is known as subacromial decompression. More specifically, the orthopaedic surgeon performs an acromioplasty, i.e. reshapes the acromion and removes part of it to create more space for the rotator cuff tendons.

Resection arthroplasty

If subacromial impingement syndrome is associated with degeneration of the acromioclavicular (AC) joint and osteoarthritis of this area is already present, a small portion of the collarbone is also removed during the impingement operation. This procedure is called resection arthroplasty and is the most common procedure for osteoarthritis of the AC joint. A portion of less than 1 cm of the end of the collarbone is resected (cut away), without interfering with the supporting ligaments. After healing, the joint is replaced by fibrous tissue, which is more flexible and at the same time eliminates friction between the bone ends.

The procedure can be performed:

Arthroscopically, by acromioplasty

This is a minimally invasive procedure, with a one-day hospital stay and rapid healing and recovery. The procedure is performed by inserting the arthroscope (a small television camera) into the shoulder joint through a small incision, which allows the orthopaedic surgeon to treat the condition with negligible surgical trauma. President Iohannis underwent this procedure here in Romania and returned to work at Cotroceni the following day. In the video below, you can see how such a procedure is carried out, in an operation performed by Ion Bogdan Codorean, senior orthopaedic consultant, Doctor of Medicine, with competence in arthroscopic surgery.

Open surgery

This involves an incision of approximately 8-10 cm through which the excess bone tissue is removed, after which the acromion is smoothed to eliminate the risk of further injury. In the case of associated conditions, the orthopaedic surgeon may also perform a resection arthroplasty of the AC joint.

Recovery after surgery

The sooner subacromial impingement syndrome is treated, the faster the recovery will be. It is therefore essential that the patient sees a doctor as soon as the pain begins, because the recovery period will be much shorter. The upper limb will regain its function once the pain has eased or disappeared completely, which can mean a period of 2 to 3 days. After surgery, the doctor recommends restoring muscle tone and joint mobility through physiotherapy.

We can see, therefore, that what we sometimes dismiss as "just a bit of shoulder pain" can develop into much more complicated health problems. Subacromial impingement syndrome can be treated successfully from its early stages. So let us not put off that visit to the orthopaedic surgeon!