Subacromial impingement sign

Introduction to the impact of the subacromial impact DeSeze and Robinson et al. (1947) studied the special structure under the shoulder and the trajectory of the large nodule, and proposed the second shoulder joint. It is also known as the subacromial joint in the European and American literature. basic knowledge The proportion of illness: 0.012% Susceptible people: no special people Mode of infection: non-infectious Complications: wear, acromioclavicular joint dislocation

Cause of impact under the shoulder

(1) Causes of the disease

Abnormal morphology of the anterior and posterior aspect of the acromion, formation of callus, formation of epiphysis of the greater tibial tuberosity, hypertrophy of the acromioclavicular joint, and other causes of a decrease in the distance between the acromion and the humeral head can cause subscapular structures. Squeeze and impact, most of which occur in the first 1/3 of the shoulder and under the acromioclavicular joint. Repeated impacts cause the bursa, tendon damage, degeneration, and even tendon rupture.

(two) pathogenesis

The impact sign is defined as: the clinical symptoms of the subacromial joint due to anatomical or dynamic reasons, in the shoulder lift, and in the abduction movement due to the impact of the subacromial tissue.

Pathological findings: According to the pathological manifestations of the impact sign, it can be divided into three phases.

Phase 1: Also known as edema and bleeding, can occur at any age, working on the arm over the head, such as stencil paint and decoration work, as well as gymnastics, swimming, tennis and baseball throwing and other sports caused by shoulder joints The use and occurrence of cumulative injury is one of the common causes. In addition, this period also includes a one-time history of simple shoulder injury, such as supraspinatus tendon caused by physical contact or severe falls, biceps long head The edema and hemorrhage of the sacral and sacral sacs. Although the muscle strength is weakened by pain in this period, there are some typical symptoms of rotator cuff tear. Physical examination is not easy to find the pain arc sign, gravel sound and chronic impact test. Positive signs, subtotal injection of lidocaine can completely relieve pain, X-ray examination is generally no abnormal findings, arthrography can not find the existence of rotator cuff rupture.

Phase 2: Chronic tendonitis and bursal fibrosis, more common in middle-aged patients, repeated impact under the shoulder to make the bursal fibrosis, thickening of the cyst wall, repeated tendon injury is chronic tendonitis, usually fibrosis and The edema coexists, the thickened bursa and tendon occupy the subacromial space, and the supraspinatus muscle outlet is relatively narrow, increasing the chance and frequency of impact. The pain symptom can last for several days and still feels during the pain relief period. Shoulder fatigue and discomfort, physical examination is easier to find pain arc and positive impact test, if there is biceps brachii stagnation, Yergason sign is positive, biceps brachial long head squat extension stretch test Pain can occur, and the pain can be temporarily relieved by a lidocaine injection test under the shoulder.

The third stage: the rupture period of the tendon, the main pathological change is the supraspinatus tendon, the biceps tendon of the biceps tendon is repeatedly damaged, the partial or complete rupture of the tendon occurs on the basis of degeneration, and the rotator cuff exit is accompanied by the impact sign. The age of rotator cuff rupture is 50 years old. The average age of patients with partial tendon rupture reported by Neer II is 52 years old. The average age of patients with complete rupture is 59 years old. The degree of tendon degeneration and repair ability and age factor Relevant, it should be pointed out that not all impact signs will cause rotator cuff rupture, and not all rotator cuff injuries are caused by impact signs. The rotator cuffs caused by impact rupture, only about 1/2 of the history of trauma, only A small number of patients have a more obvious or heavier history of trauma. In most cases, the injury strength is actually less than the external force required to cause complete rupture of the rotator cuff, indicating the importance of the degeneration factor of the tendon itself.

In the initial stage of rupture of the rotator cuff, the pain is intermittent. The pain episode is closely related to the frequency of the impact. After the labor and nighttime, the symptoms are aggravated and the rest is obviously relieved. If there is chronic shoulder bursitis, the pain is persistent and Intractable, the limb is weak due to shoulder pain, the external rotation muscle and the abductor muscle strength weakened, in the sagging position of the limb, 90% of the external rotation muscle strength comes from the infraspinatus muscle, when the limb is in the abduction 90° position When the external rotation muscle strength test, the external rotation muscle muscle strength mostly comes from the posterior part of the deltoid muscle. As the disease course prolongs, the supraspinatus muscle, the infraspinatus muscle and the deltoid muscle successively appear muscle atrophy, the muscle strength is weakened, and the mechanical mechanics are easy to check. Found pain arc signs, gravel sounds, positive impact test, in addition, the positive rate of arm fall arrest is also higher, the rotator cuff tears also appear ankle instability, complete rotator cuff tears the ankle joint cavity Joint fluid communication occurs with the acromion sac, but most patients can still maintain a certain degree of mobility of the ankle joint, incomplete rotator cuff rupture or long-term painful braking, but it is easy to cause joint stiffness and loss of function.

Arthrography is still the most reliable diagnostic method for complete rotator cuff rupture, but neither angiography nor ultrasonography can show or determine the size of the rupture. Clinical physiology examinations show significant atrophy of the supraspinatus tendon, weakened muscles, and arm fall. Positive, and there is a biceps tendon rupture, and X-ray film shows that the peak-humeral head spacing is significantly reduced ( 0.5cm), suggesting the existence of large rotator cuff fracture.

The impact injury of the biceps tendon is generally associated with the injury of the supraspinatus tendon. The extensive tearing of the rotator cuff can promote the rapid deterioration of the biceps tendon injury. The impact sign 2 may be combined with the biceps. In the second period, partial or complete rupture of the tendon may occur in the second stage, the proximal internodal sulcus tenderness, Yergason's sign positive, and the shoulder squatting biceps long head sputum test positive biceps biceps The performance of the long head sputum lesion, when doing the flexion elbow biceps resistance test, if the muscle strength is significantly weakened, it means the possibility of biceps tendon rupture, shoulder arthrography and arthroscopy help Make a definitive diagnosis.

Prevention of impact under the shoulder

Prevent violent injuries.

Subacromial impact syndrome Complications wear acromioclavicular joint dislocation

1. Treatment of concurrent internal impact signs

Dabidson et al. describe the internal impact of the supraspinal muscle between the humeral head and the posterior superior part of the ankle when the upper arm is abducted by 90° and the external rotation is extremely external. The arthroscopy can be found in the posterior superior iliac crest of the shoulder. The lips have wear and the joint surface of the rotator cuff has lesions. Under the arthroscopy, the rotator cuff should be cleaned and the degenerative lips should be cleaned. Postoperative rehabilitation can achieve good results.

2. Treatment of unstable ankle joints

Due to the significant symptoms of the rotator cuff, the signs often obscure the weak manifestations of ankle instability, so the ankle instability of the concomitant impact is difficult to diagnose, and neglecting the unstable treatment only under the subacromial decompression Or rotator cuff cleaning, the surgical effect is very poor, therefore, it is necessary to determine whether the cause of subacromial impact is structural or dynamic before surgery. If there is motility, it must strengthen muscle strength at the same time. Surgery strengthens the stability of the ankle joint.

3. concurrent acromioclavicular joint osteoarthropathy

Below the acromioclavicular joint is the exit site of the supraspinatus muscle, which is also a common site for the impact of the subacromial impingement. Missed acromioclavicular joint osteoarthritis is a common cause of failure of the subacromial impact. Lozman et al reported that the shoulder is reduced. Partial resection of the lateral and lateral clavicle can be performed simultaneously under arthroscopy. After an average of 32 months of follow-up, the function, strength, and range of motion of the 18 patients improved, and 16 patients had reduced pain and a good overall rate of surgery. It is 89%.

Symptoms of subacromial impingement symptoms Common symptoms Subcutaneous tissue edema tendon rupture impact sign

The impact sign can occur at any age from the age of 10 to the old age. Some patients have a history of shoulder trauma. A considerable number of patients are associated with long-term excessive use of the shoulder joint. The rotator cuff, bursa is repeatedly damaged, tissue edema, bleeding, Degeneration or even tendon rupture causes symptoms. Early rotator cuff hemorrhage, edema and rotator cuff rupture are similar in clinical manifestations. It is easy to make the diagnosis confusing. The impact sign should be differentiated from shoulder pain caused by other causes, and the impact sign should be distinguished. Which period belongs to, this is very important for the diagnosis and treatment of this disease.

Examination of the impact of the subacromial impact

Blood and blood biochemical examinations do not directly help the diagnosis of impact signs. Blood cell count, blood cell sedimentation rate, rheumatoid factor, and blood uric acid determination are necessary to rule out other joint diseases.

X-ray film should routinely include the upper arm neutral position, the internal rotation position, the external rotation position of the external rotation position and the axial position projection, showing the shoulder, the humeral head, the shoulder and the acromioclavicular joint, and the X-ray film can identify Calcium salt deposition under the shoulder, ankle arthritis, acromioclavicular arthritis, abnormal development of the axillary epiphysis and other bone diseases.

X-ray projection (Y phase) of the supraspinatus tendon exit is important for understanding the structural stenosis of the outlet and measuring the shoulder-humidal head spacing by pulling the arm down to make it shoulder-shoulder In the horizontal position, the X-ray tube is inclined downward from the healthy side to the affected side by 10°, pointing to the shoulder and shoulder and the lower gap.

X-ray film is not specific for the diagnosis of stage 1, stage 2 and stage 3 impact signs, but it has reference value for the diagnosis of subacromial impact signs when it has the following X-ray signs.

1. The formation of osteophytes in the large nodules is caused by repeated collisions between the large nodules and the shoulders, and generally occurs in the ankles of the sacral muscles.

2. Shoulder peaks are too low and hooked shoulders.

3. The underside of the shoulder is dense, irregular or has osteophytes formed, the shoulder ligament is impacted, or repeatedly stretched to form an epiphyseal under the periosteum under the acromion.

4. The acromioclavicular joint degenerates and proliferates, forming a downwardly protruding epiphysis, resulting in a narrow outlet of the supraspinatus.

5. Shoulder-humeral head spacing (AH spacing) is reduced, the normal range is 1.2 ~ 1.5cm, <1.0cm should be narrow, 0.5cm suggesting extensive rotator cuff tear, biceps long head squat completely broken Loss of the function of pressing down the humeral head, or other dynamic imbalances, can also cause the AH spacing to shrink.

6. The erosion of the bone under the anterior shoulder or acromioclavicular joint, absorption; decalcification of the greater tibia of the humerus, erosion and absorption or the densification of the bone.

7. The humeral nodule is rounded and passivated. The boundary between the humeral head joint surface and the large nodule disappears and the humeral head deforms.

The above 1- to 3-point X-ray findings combined with clinical pre-shoulder pain symptoms and positive impact tests should consider the presence of impact signs. The X-ray signs at points 4-7 are late in the impact sign.

In addition to static X-ray film and measurement at different positions, dynamic observation under X-ray monitoring should be performed. In the direction and angle of the impact sign, the affected arm should be repeatedly lifted, abducted, etc., to observe the humerus. The relative anatomical relationship between the large nodules and the shoulder and shoulder arches, dynamic observation is particularly important for the diagnosis of dynamic impact signs.

In the late stage of the impact sign, the rotator cuff is broken, and angiography is still the most specific diagnostic method for complete rotator cuff rupture.

Indications for shoulder joint angiography:

1 Age is over 40 years old, clinical manifestations support impact signs combined with rotator cuff injury, non-surgical therapy for more than 3 months.

2 Under the shoulder peak crash with sudden abduction, external rotation muscle loss.

3 chronic shoulder pain accompanied by biceps femoris rupture, 4 refractory shoulder pain, with ankle instability.

When the shoulder arthrography is found to contrast the contrast agent from the ankle joint into the acromion sac or deltoid sac, the complete rupture of the rotator cuff can be diagnosed. The shape of the biceps brachii and the filling of the tendon sheath can be observed. Judging whether there is rupture of the biceps brachii tendon, small rotator cuff rupture and incomplete rotator cuff rupture are difficult to display during angiography, and scapular sac angiography also contributes to the diagnosis of complete rotator cuff tear, but due to shoulder The variation of peak sac morphology and the overlap of development have limited practical value. The non-invasive diagnostic method MRI has high sensitivity to soft tissue lesions. With the accumulation of experience, the specificity of MRI examination for the diagnosis of rotator cuff injury is also Increasingly, it has gradually become one of the routine diagnostic tools.

Ultrasound diagnosis is a non-invasive method with reproducibility. It has certain diagnostic value for rotator cuff edema, hemorrhage, and intra-orbital rupture and complete rupture. There is no uniform standard for ultrasound diagnosis of rotator cuff injury. There are still some difficulties in the interpretation. It is still to be further explored and summarized. For the identification and diagnosis of partial tendon rupture in the rotator cuff, ultrasonography may be a direction that should be paid attention to in the future.

Arthroscopic surgery is an intuitive diagnostic method that can detect the extent, size, and shape of tendon rupture, and has a diagnostic value for the partial rupture of the supraspinatus tendon and the biceps femoris head, and can be shouldered. In the sag of the peak, the bursal lesion and the rupture of the supraspinatus sac surface are observed. In addition, the diagnosis can be performed at the same time, such as the reduction of the subacromial space, the removal of the lesion and the removal of the anterior shoulder peak. Anterior acromioplasty can be performed. Arthroscopic examination is a method of injury examination. It needs to be performed under anesthesia, and it also needs certain experience and technical equipment. It is not easy to carry out extensively.

Diagnosis and identification of subacromial impact

Diagnostic criteria

Common symptoms of each period of impact:

1. Chronic dull pain in front of the shoulder

Symptoms worsen during ascension or outreach activities.

2. Pain arc sign

Pain or symptoms worsen in the range of 60° to 120° on the affected arm. The pain arc sign is only present in some patients and is sometimes not directly related to the impact sign.

3. Gravel sound

The examiner holds the front and rear edges of the affected arm by hand, so that the upper arm can be used for internal, external rotation and flexion. When the extension is extended, the sound of the gravel can be smashed, and the auscultation with a stethoscope is more audible and obvious. More common in the impact of the second phase, especially in patients with complete rotator cuff fracture.

4. Muscle weakness

Significantly weakened muscle strength is closely related to the late impact of extensive rotator cuff tear. In the early stage of rotator cuff tear, shoulder abduction and external rotation weakened, sometimes due to pain.

5. Impact test

The examiner pressed the patient's ipsilateral scapula with the hand and lifted the affected arm. If the pain occurred due to the impact of the big tibia and the shoulder, it was positive for the impact test. Neer II believed that the test had a great impact on the identification of the impact. Clinical significance.

6. Impact injection test

10ml of 1% lidocaine was injected into the shoulder sac below the acromion. If there is no shoulder joint dyskinesia before and after injection, the symptoms of shoulder pain disappeared completely after the injection, and the impact sign can be established, such as pain after injection. Only partial relief, and there is still joint dysfunction, the possibility of "freezing the shoulder" is greater, this method can identify the shoulder pain caused by non-impact sign.

Diagnosis can be established based on medical history, clinical symptoms, signs and tests, X-ray films, magnetic resonance, ultrasound, and joint angiography.

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