Impingement Syndrome – Shoulder

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Synonyms: Shoulder syndrome, subacromial syndrome, periarthritis humeroscapularis (PHS)

 

Targeted diagnosis and effective treatment for shoulder pain

The number of persons suffering from problems in the shoulder and consequently having to consult a physician or therapist is growing steadily. One factor contributing to this phenomenon is most likely a personal expectation to remain active and pain free even at a mature age. Another factor is, however, the certainly welcomed development in our society to increase physical activity in general. This development is already blatantly referred to as "new social disease shoulder pain". Below, we would like to give "from the practice for the practice" an overview of the most common cause of shoulder pain, the IMPINGEMENT SYNDROME. With our practice-relevant information, we hope to support your daily work activities effectively. Of course, from a differential diagnosis point of view it is important to consider that in addition to the impingement syndrome numerous other causes such as internal diseases (CHD, liver, bronchial CA etc.) or neurogenic disorders (cervical disc prolapse, neoplasms, etc.) may be responsible for shoulder pain.

Definition

We refer to an impingement syndrome of the shoulder when the condition indicates painful irritation and a degeneration of tendons and bursae due to anatomical tightness in the shoulder joint. This narrowness is caused when the arm is being raised to shoulder height and the gap between the anterior edge of the acromion and the head of the humerus narrows. The acromion rubs against (or "impinges" on) the tendon and the bursa. This leads to increased friction and thus cause irritation of the rotator cuff, especially the supraspinatus tendon and subacromial bursa. The disease is often caused by “overhead activities” (overusing the arm in upward stretching motions) such as in sports like tennis, throwing or volleyball or in certain professional groups, like house painters. However, the impingement syndrome also developed with age due to the age-related degeneration process.

Causes

The shoulder is the most mobile, thus also the most unstable joint in the human body. In contrast to most other joints, the stability of the shoulder is not ensured primarily by the bony joint partner, but by ligaments, the joint capsule and the muscles. Due to the complex soft tissue conditions of the shoulder joint, particularly the tendon at the humeral head of the so-called rotator cuff (composed of the muscle group supraspinatus, infraspinatus, teres minor, and subscapularis) these are very prone to damage in the sense of chronic irritation or degeneration. The supraspinatus muscle is primarily responsible for the lateral lifting of the arm above 90°, which is most painful when impingement syndrome is present. The space at the shoulder joint, into which the supraspinatus tendon slides when lifting the arm, is very limited by the acromion (acromion and coracoacromial ligament - the outward end of the shoulder blade).

Overloading can lead to acute tendonitis or chronic tendonitis (tendonitis) , often accompanied by bursitis. Because of the innate unfavorable shape of the acromion (hooked acromion type II and III according to Bigliani classification), the incidence of subacromial impingement syndrome increases significantly. Moreover, age-related degenerative processes such as an ossification of the coracoacromiale ligament contribute to an impingement syndrome. Another reason for a shoulder impingement can be calcium deposits in the rotator cuff be (calcific tendinitis). A permanent irritation of the tendon leads to tendon degeneration and may eventually develop into a  tendon rupture (degenerative rotator cuff rupture). In addition, chronic shoulder pain causes malfunction of the entire shoulder girdle. Typical functional disorders are muscular imbalances, in particular atrophy of the shoulder girdle muscles, tension in the autochthonous back muscles, and the trapezius muscle.

Diagnosis

Case history
Patient’s history reveals complains mostly about pain in the shoulder and in the proximal humerus during lateral raising of the arm above 90°. The pain is particularly pronounced during abrupt movements or under stress, e.g. when lifting objects above head height. However, patients’ history often also indicates pain not related to overload or stress, but rather during resting and sleeping at night.

Clinical examination
On examination, the shoulder indicates in most cases few or no findings. Passive, the shoulder can usually moved freely (170° flexion, abduction 90°, internal / external rotation 70/0/90 °). The function tests painful-arc, Hawkins- and Jobe test are usually very positive, e.g. painful. In these impingement tests, the rotator cuff and bursa between the humeral head and the acromion are compressed, which is painful to the current state of irritation or damage. A preliminary motion and functional examination of the cervical spine in addition to exploratory survey of the neurological status (sensitivity test, tendon reflexes, and gross motor) are obligatory to the examination of the shoulder in order to exclude that these are the cause of shoulder pain.

Imaging diagnostics 
Ultrasound: to assess the subacromial bursa and rotator cuff, evaluation of a possible joint effusion. X-ray: shoulder on three levels (ap / aro, ap / iro, outlet view / Y recording) to assess the bony condition (hooked acromion, arthritis, calcific tendinitis). MRT: comprehensive information on all bony and soft tissue structures of the joint, particularly for suspected rotator cuff and to assess the inflammatory condition.

Therapy

The rule is that in an impingement syndrome the treatment opportunities for the patient are better the sooner treatment is started. The primary therapy should be conservative. After conservative treatment has been unsuccessful over a period of three to four months, indications for a surgical treatment should be reviewed.

Conservative treatment

Resting the shoulder
The most important measure should be to avoid movements that cause pain, such as stressful and repetitive movements. This means to rest the shoulder, e.g. to refrain from sport activities that stress the shoulder and accordingly to avoid occupational, stressful shoulder movements.

Medicinal treatment
Recommended are non-operative measures such as a medicinal therapy, e.g. orally administered NSAID (diclofenac 2 x 75 mg / d or ibuprofen 3 x 600 mg / d for two to three weeks). An alternative is a local infiltration treatment of subacromial space, i.e. injections peritendinous into the subacromial bursa. In the acute phase e.g. triamcinolone 10 mg and dexamethasone 4 mg in 10 mL bupivacaine 0.5% (Caution with corticoids: time between two injections should be at least 4 weeks, with a total of no more than three repeats!). In chronic cases, if necessary, 1 Amp. Traumeel on 10 ml bupivacaine 0.5% six times at weekly intervals. Regarding joint injections we refer to the recommendation of the German Society of Orthopedics and Traumatology (DGOU).

Physiotherapy
Physiotherapy aims at compensating muscular imbalances where by the focus is on achieve a relieving subacromial space gain in the shoulder, which requires that the humeral head ascending muscles must (supraspinatus, deltoid) detonisiert and the humeral head descending muscles (external rotators: infraspinatus, teres minor, rotators: subscapularis) are strengthened. Especially helpful and efficient are instructions to guide the patient to exercise independently. Locally administered measures that activate the metabolism are cross friction, ultrasound, electric or cryotherapy, promote the regeneration process of the tendon tissue.

Shockwave treatment
Shockwave therapy is an alternative treatment for chronic painful tendon irritation, especially when classic conservative treatment measures such as medication, physical therapy, etc. do not lead to a lasting relief of the symptoms. Targeted shock wave therapy increases the metabolic activity is induced into the tendon injury. Due to the improved metabolism of otherwise bradytrophic tendon tissue, the capability of natural regeneration will be increased. As a rule, three treatments are carried out at intervals of one week, each, whereby 2,000 to 2,500 pulses are applied at a frequency of approximately 7 Hertz.

Operative Therapy

Surgical treatment should be considered if despite a conservative treatment over a period of three to four months; recurrent, stress-related complaints persist. Surgical measures treat impingement syndrome treated causally and possibly prevent chronic tendon damage, possibly even a rotator cuff rupture. Such a surgical procedure is referred to as "subacromial decompression". This procedure should only be performed arthroscopically, since an open surgery can cause excessive collateral damage, carry high risks, and significantly delays the postoperative healing process. Arthroscopic subacromial decompression can be done on an in-patient bases (hospital stay is one to two nights) or possibly even on an outpatient basis.

Surgical procedures

Arthroscopic subacromial decompression (ASD)
Under general anesthesia, the thickened, chronically inflamed subacromial is first resected via two small portals. Following the narrow subacromial space expanded in that the anterior inferior border of the acromion is removed. Depending on the finding, the thickened coracoacromiale ligament is also removed and possibly partially resected. If a narrowing of subacromial space due to an arthrotically thickened acromio-clavicular joint (ACG) is present, it will be treated additionally. In a chronically degenerated rotator cuff needling of the tendons may possibly have to be done. This iatrogenic microtraumatization induces a regeneration processes at the tendon. In a superficial tendon damage, the tendons are smoothed. If there foci of calcification are found in the rotator cuff (calcific tendinitis), the calcification is also removed. Postoperatively the arm the arm should be rested and possible strain avoided for the first four to six weeks. However, complete immobilizing of the arm as was required previously after open surgery is not required.

Physiotherapy should accompany the recovery process since the shoulder can be passively mobilized in the first phase of the physiotherapy. During the second phase of physiotherapy, coordination, propriozeptions- and strength training will slowly be introduced in order for the patient to regain full capacity for sport or occupational activities. At proper indication, arthroscopic subacromial decompression when performed by an experienced surgeon has shown excellent results. Additionally, arthroscopic procedure carries very low surgical risks (infection, wound healing, etc.). The cosmetic advantage of a surgery requiring only small cuts of few millimeters should also be mentioned. It is particularly noteworthy that after an arthroscopic surgery, the pain is reduced significantly and mobilization of the affected arm takes place much earlier, e.g. immediately after the surgery. Patients, who do not overuse the arm occupationally, can generally return to work within one to two weeks. Depending on intra-operative findings, sports activities can usually be resumed after six to 10 weeks.

Differential diagnoses for shoulder pain
Pain in the shoulder is only a symptom. Aside from the certainly most often occurring impingement syndrome, it is therefore important to consult with orthopedic specialists in order to find the cause. In the area of internal medicine, differential diagnosis take in particular coronary heart disease, liver disease, bronchial Ca, lymphoma or other neoplasms into consideration. Other causes of shoulder pain can be a cervical herniated disc, neuritis or functional disorders, such as strain in the the neck and shoulder area.

From the practice for the practice

Intra-articular injections or punctures as well as infiltrations close to the tendons are an important part of work in orthopedics, be it for differential diagnoses or therapies. Here the proper technique is crucial. We would like to illustrate the in our daily work frequently performed injection technique for a subacromial infiltration at the shoulder for the pharmacological treatment of the impingement syndrome.

Whenever infiltrations are part of the treatment, the patient must be informed about potential risks and complications of intra-articular injections. The information should be documented in the patient's file. Written consent is not required. The injection area should be free from clothing and longer hair should possibly be cut with scissors. An extensively applied spray disinfection should be performed carefully (note the time the disinfectant must be exposed to the skin!). Wearing sterile gloves and a mouth guard is only mandatory if during the injection treatment the needle is disconnected from the syringe (e.g. in infiltrations of several substances consecutively or joint puncture and subsequent infiltration through the inserted cannula). An aspiration test to avoid intravascular injection must be performed prior to injection.

Positioning

The patient should be seated upright in a comfortable position with the arm hanging by his side and rotated outward.

Procedure

Palpation of the dorsolateral acromion edge, which serves as a guiding structure, with the free hand. The injection needle (20-23 G, length 40-70 mm) is advanced posterior, about 1.5 cm distal and 1.5 cm medial to the inferior dorsolateral acromion neck at an angle of about 30 ° to anteriorly cranial to a depth of about 5 cm. the infiltration (volume 5-10 ml) is performed following aspiration test.

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