Rotator cuff injury

Introduction to rotator cuff injury The rotatorcuff is a cuff-like muscle-like structure formed by the supraspinatus muscle, the infraspinatus muscle, the subscapularis muscle, and the small round muscle tendon in front of, on, and behind the humeral head. Clark et al believe that the rotator cuff muscles merge at the end of the proximal humeral nodule, and the ligament of the sacral ligament is strengthened on the deep and shallow sides between the supraspinatus and the infraspinatus. basic knowledge Sickness ratio: 0.0001% Susceptible people: no special people Mode of infection: non-infectious Complications: muscle atrophy

Causes of rotator cuff injury

(1) Causes of the disease

The causes of rotator cuff injury are four main arguments: blood transport theory, degeneration theory, impact theory and trauma theory.

Degeneration theory

The histopathological manifestations of tendon degeneration described by Yamanaka through the autopsy specimen study are: cell deformation in the rotator cuff, necrosis, calcium deposits, fibrin-like thickening, hyalinosis, partial muscle fiber breaks, fibrillation and collagen waves. The morphology disappeared, the arterioles proliferated, the cartilage-like cells appeared in the tendons, and the degeneration of the rotator cuffs was characterized by the replication and irregularity of the tidal line. The normal four-layer structure (intrinsic tendon, tidal line, mineralized fiber) Cartilage and bone are irregular or disappear, or granulation-like, and these changes are rare in adults under the age of 40, but tend to increase with age.

Uhtoff et al. showed the pathological features of the tendon lesion (enthesopcethy): the muscle fibers are arranged at the stop point, the fracture and the formation of the callus, the distance between the edge of the humeral head cartilage and the supraspinatus tendon - the cuff ( The degree of degeneration of sulcus is proportional to the width of the cuff, and the degeneration of the tendon reduces the tension of the tendon and becomes an important cause of rotator cuff fracture.

Degenerative degeneration of tendons, partial rupture of tendons, and complete rupture are common causes in elderly patients.

2. The theory of blood transport

The "danger zone" first described by Codman is located within 1 cm of the distal end of the supraspinatus tendon. This avascular region is the most common site of rotator cuff tear. The perfusion studies of cadaveric specimens confirm the existence of the dangerous zone, ie the sac surface. The blood supply is better than the articular surface, and the tear of the articular surface is higher than that of the lateral surface of the bursa. Brooks found that there is also a vascular area within 1.5 cm of the distal inferior tendon, but the incidence of tear of the supraspinatus muscle is much higher. In the lower part of the tendon, there should be other factors besides blood supply.

3. Impact theory

The concept of impingement syndrome of the shoulder was first proposed by Neer II in 1972. He believed that rotator cuff injury was caused by an impact under the shoulder, which occurred mostly in the first 1/3 of the shoulder and shoulder. Below the locking joint, the Neer II is divided into the outlet impingement syndrome and the non-outlet impingement syndrome according to the anatomy of the impact sign. He thinks that 95% The rotator cuff rupture is caused by the impact sign. The supraspinatus tendon passes between the shoulder peak and the large nodule. The biceps femoris longus is located deep in the supraspinatus muscle, over the top of the humeral head and ends at the top or shoulder. Long, when the shoulder joint is moving, the two tendons move back and forth under the shoulder blade, and the degeneration or abnormal development of the shoulder and subscapular structures, or the instability of the ankle caused by the power, can lead to the upper The tendon of the tendon, the biceps brachii and the subacromial tendon, the early bursal lesion, and the deterioration and rupture of the tendon in the middle and late stages.

However, some clinical studies have shown that a considerable part of the cases of rotator cuff tears are not related to the impact under the shoulder, but simply due to damage or tendon degradation. In addition, there are cases of anatomical abnormalities with subacromial impact. The rotator cuff rupture occurs, so the subacromial impact is an important cause of rotator cuff injury, but it is not the only factor.

Trauma

(1) General: Trauma has been widely accepted as an important cause of rotator cuff injury. Labor injury, sports injuries and traffic accidents are common causes of rotator cuff trauma. Neviaser et al found in patients over 40 years old. In the anterior ankle dislocation, if the shoulder is still unable to abduct after the reduction, the incidence of rotator cuff injury is 100%, and the sacral nerve injury only accounts for 7.8%. In the elderly, no trauma caused by fracture or dislocation It can also cause rotator cuff tears. There are rotator cuff avulsion fractures in any displaced large nodular fractures. Trauma can be divided into severe violent trauma and repeated minor trauma according to the size of the injury violence. The latter is in the rotator cuff injury. It is more important than the former. Repeated micro-injury in daily life activities or exercise causes microtear of muscle fibers in the tendon. If this micro-fracture does not have enough time to repair, it will further develop into partial or full-thickness tendon tear. This pathological process is more common among professional athletes engaged in throwing sports.

(2) Forms of violence: The common forms of violent effects of acute injuries are:

1 The upper arm is directly pulled by violence, causing damage to the upper tendon.

2 The upper arm is suddenly and extremely adducted by the external force, so that the supraspinatus tendon is excessively pulled.

3 The ankle is subjected to a downward-directed hedging injury under the joint sac, causing the supraspinatus tendon to be relatively pulled and injured by the impact under the shoulder.

4 Direct violence from the outside of the shoulder produces a downward impact on the upper end of the humerus, causing the rotator cuff to be pulled and damaged.

In addition, less common injuries include sharp stab wounds and firearm injuries.

(3) Degeneration factors.

In summary, the intrinsic factor of rotator cuff injury is the tissue degradation of the rotator cuff tendon with age, and the inherent weakness of the vascular region in the anatomical structure, while the trauma and impact accelerate the rotator cuff degradation and promote The occurrence of the fracture, as Neviaser emphasized, the four factors caused the rotator cuff degeneration process to varying degrees. No single factor can cause the rotator cuff injury alone. The key factors should be analyzed according to the specific situation. Out.

(two) pathogenesis

The rotator cuff injury can be divided into three categories according to the degree of injury: contusion, incomplete fracture and complete fracture.

The rotator cuff contusion makes the tendon congested, edema and even fibrosis, is a reversible injury, the shoulder sac of the tendon surface is accompanied by a corresponding inflammatory inflammatory reaction, the bursa has exudative changes, the rotator cuff tendon fiber Partial rupture can occur on the articular surface of the supraspinatus tendon (below) or on the flank (upper side) of the sac, and inside the tendon. When the incomplete fracture is not properly treated or fails to repair, it often develops into complete fracture, completeness. Fracture is a full-thickness rupture of the tendon, which causes a penetrating injury to the ankle joint and the acromion sac. This injury is more common in the supraspinatus tendon, followed by the subscapularis tendon and the small round tendon, and the supraspinatus tendon and the underarm. It is not uncommon for the tendon to be affected at the same time.

The direction of the fissure after the tendon rupture is perpendicular to the direction of the muscle fiber, which is called the transverse fracture; the direction of the rupture is consistent with the direction of the muscle fiber, which is called the longitudinal fracture, and the division of the rotator cuff is also a longitudinal fracture, which is a special type of injury, according to The range of tendon rupture can be divided into three types: small tear, large tear and extensive tear. According to Lyons classification: small <3cm; medium size is 3-4cm; large size is <5cm; super large>5cm, and The two tendons were involved. The author's classification is small fractures: the fracture range of a single tendon is less than 1/2 of the transverse diameter of the tendon; large fracture: the length of the single tendon is greater than 1/2 of the transverse diameter of the tendon; extensive fracture: the range involves 2 Or more than 2 rotator cuff tendons with retraction and defect of the rotator cuff tissue.

It is generally believed that the damage within 3 weeks is a fresh injury, the damage of 3 weeks or more is an old injury, the fracture of the fresh tendon is not neat, the muscle is edematous, the tissue is crunchy, there is exudation in the ankle joint cavity, and the old fracture end is broken. Scars have formed, smooth and blunt, relatively hard, a small amount of cellulose-like exudate in the joint cavity, and the bare surface of the articular surface near the large nodule is covered by vasospasm or granulation tissue.

Shoulder sleeve injury prevention

Prevent violent injuries.

Anterior rotator cuff injury Complications muscle atrophy

Older patients who are also treated in time may have different degrees of "freezing" of the shoulder joint.

Symptoms of rotator cuff injury Common symptoms Muscle atrophy Dull pain Nodules Joint contracture pain Arc sign

Clinical manifestation

(1) History of trauma: a history of acute injury, as well as a history of repetitive or cumulative injury, has a reference for the diagnosis of this disease.

(2) Pain and tenderness: The common site is pain in the front of the shoulder. It is located in front of and outside the deltoid muscle. The pain in the acute phase is severe and persistent. In the chronic phase, it is spontaneous dull pain. After the shoulder activity or after the load is increased, the symptoms are aggravated. Passive external rotation of the shoulder joint also aggravates the pain. Aggravation of nocturnal symptoms is one of the common clinical manifestations. The tenderness is more common in the proximal side of the greater tibial tuberosity or in the subacromial space.

(3) dysfunction: large rupture of the rotator cuff, active shoulder lifting and abduction functions are limited, the abduction and pre-lift range are less than 45 °, but the passive range of activity is not significantly limited.

(4) Muscle atrophy: Those with a history of more than 3 weeks have different degrees of atrophy of the shoulder muscles, and the deltoid muscle, the supraspinatus muscle and the infraspinatus muscle are more common.

(5) secondary contracture of joints: those with a course of more than 3 months, the extent of shoulder joint activity is limited, and the limitations of outreach, external rotation and lifting are more obvious.

2. Special signs

(1) arm drop sign: passively raises the arm to the range of 90° to 120°, removes the support, and the arm is unable to support itself and the arm falls and the pain is positive.

(2) Impingement test: The shoulder is pressed down, and the arm is passively lifted, such as if there is pain in the subacromial space or if it is not lifted.

(3) pain arc syndrome (pain arc syndrome): when the arm is lifted in the range of 60 ° ~ 120 ° in the range of shoulder or subacromial area, it is positive, which has certain diagnostic significance for scapular contusion and partial tear.

(4) Ankle joint internal friction sound: that is, the ankle joint has frictional or pulverized sound in active or passive activities, which is often caused by scar tissue at the end of the rotator cuff.

Examination of rotator cuff injury

X-ray film

X-ray plain film examination is not specific to the diagnosis of this disease. The distance between the shoulder and the humeral head should be no less than 12mm when the distance is 1.5m. If it is less than 10mm, it is generally suggested that there is a large rotator cuff tear in the deltoid muscle. Traction can promote the humeral head to move up, X-ray plain film shows a narrow subacute gap, in some cases, the surface of the large nodular cortical bone is irregular or osteophyte formation, bone cancellous bone atrophy and loose, in addition If the position of the shoulder is too low, the hook-shaped shoulder and the sub-shoulder joint surface are hardened, and the irregular X-ray performance provides the basis for the impact factor. The dynamic observation of the lifting motion of the affected arm can be observed. The relationship between the nodules and the shoulders and the presence of subacromial impact, X-ray film examination also helps identify and exclude shoulder fractures, dislocations and other bone and joint disorders.

2. Arthrography

The ankle joint communicates with the scapula of the subscapularis muscle and the long head tendon sheath of the biceps brachii under normal anatomy, but it does not communicate with the scapular sac or deltoid sac. If there is a shoulder in the ankle arthrography The development of the peak glide sac or deltoid sac sac indicates that the occlusion structure - the rotator cuff has broken, causing the contrast agent in the ankle joint cavity to overflow through the rupture port and enter the scapular sac or deltoid sac. The angiography of the ankle joint is a very reliable method for the complete rupture of the rotator cuff, but partial diagnosis of the rotator cuff cannot be correctly diagnosed.

The ankle arthrography method is as follows: the patient is lying on his back, marking the tip of the arm of the arm, disinfecting the skin, laying a sterile towel, and making a local skin infiltration anesthesia at the outside of the condylar tip and below 1 cm, followed by slender Needle vertical puncture, into the joint cavity, or introduce the needle tip into the intercondylar space under X-ray induction, first inject a pre-formulated mixed contrast agent (60% diatrizoate 20ml, plus 2% lidocaine 10ml and water for injection) 10ml, prepared as a mixed solution containing 30% diatrizoate and 0.5% lidocaine 40ml) 1ml, observe the distribution of contrast agent on the surface of the humeral head and ankle joint, if the contrast agent is uniform with the bone or ankle joint The distribution indicates that the puncture is successful, and the remaining contrast agent is slowly injected to fully fill the ankle joint cavity. Generally, the volume of the ankle joint cavity is in the range of 15 to 25 ml, and the internal rotation and external rotation position of the sagging position of the affected arm. , and the inner and outer rotation positions of the upper position, as well as the inner and outer rotation positions of the abduction 90° position, respectively, observe the shape of the ankle joint and whether the contrast agent overflows, and record the film at the clearest position. .

Ankle arthrography can not only show rupture of the rotator cuff, but also determine the size of the crevice according to the location and extent of the contrast agent spillage. In addition, it can also identify the rupture of the rotator cuff, ankle contracture, "freezing shoulder" and ankle instability. Such pathological changes, such as double contrast angiography of diatrizoate and gas (the former 4 ~ 5ml, the latter 20 ~ 25ml), the axial phase of the shoulder abduction 90 ° can also clearly show the anatomy of the labrum and joint capsule This is undoubtedly a useful auxiliary diagnostic method for CT examination without conditions.

Iodine allergy test should be done before ankle arthrography.

3. CT examination

The use of CT examination alone has little significance in the diagnosis of rotator cuff lesions. The combination of CT and arthrography has a certain significance for the discovery of rupture of the subscapularis and infraspinatus muscles and the pathological changes found in the rotator cuff. When the ankle is unstable, CT examination can help to find abnormal and unstable performance of the anatomy of the scapula and the humeral head.

4. Magnetic resonance imaging

Magnetic resonance imaging is an important method for the diagnosis of rotator cuff injury. It can show the pathological changes of tendon tissue according to the different signals of edema, congestion, rupture and calcium salt deposition. The advantages of magnetic resonance imaging are non-magnetic. Invasive examination method, reproducible, and sensitive to soft tissue injury, with high sensitivity (more than 95%), but high sensitivity leads to higher false positive rate, further improving the specificity of diagnosis It is still necessary to conduct an in-depth study of imaging and pathology and the accumulation of case numbers and practical experience.

5. Ultrasound diagnosis method

Ultrasound diagnosis is also a non-invasive diagnostic method. It is simple, reliable, and can be repeated. Its ultrasonic diagnosis can make clear resolution of rotator cuff injury. High-resolution probe can show rotator cuff edema, thickening and other contusive pathology. Altered, it shows rotator cuff defect or atrophy and thinning when the rotator cuff is broken; it shows the broken end and fissure when it is completely broken, and shows the range of tendon defect. Ultrasound diagnosis is better than arthrography in the diagnosis of tendon insufficiency.

6. Arthroscopy diagnosis

Shoulder arthroscopy is a minimally invasive procedure commonly used for suspected rotator cuff injuries, labial lesions, biceps brachial palpebral fractures (SLAP) lesions, and ankle instability. The arthroscopic diagnosis of rotator cuff injury usually uses the lateral upper extremity abduction 70° traction position or semi-sitting position (beach chair position), and the rear approach is made with the entrance of the posterior lateral angle of the acromion 2 to 3 cm below. Marked by the tip of the condyle, the arthroscope is inserted between the infraorbital muscle and the small round muscle, and the drainage guide needle is inserted from the front under the guidance of the arthroscope. The order of the endoscope in the joint cavity is, in front of the joint: Shoulder blade, anterior margin lip, anterior inferior margin, patellar ligament, subscapularis tendon and supraspinatus tendon, and scapular sleeve gap; top: supraspinatus tendon and its large nodules proximal stop, biceps long head and its shoulders on the trochanteric starting point and the surrounding labrum (for the injury of the subscapularis muscle, arthroscopy should be observed from the anterior approach); rear: humeral head joint surface and the back of the head, and the lower back of the shoulder and the squat Lips, if necessary, can be inserted into the endoscope from the subacromial gap to see if the rotator cuff surface is damaged Partial or tendon, and can observe whether there osteophytes or other impact factors acromion, different sliding direction do glenohumeral while endoscopic observation, traction, can understand joint stability.

Diagnosis of rotator cuff injury

It is not easy to make a correct diagnosis of rotator cuff rupture. Anyone with a history of shoulder trauma, pain in the front of the shoulder with tenderness near the large nodules or subacromial region, if there is a combination of any of the above 4 special positive signs Should consider the possibility of rotator cuff tear, such as accompanied by muscle atrophy or joint contracture, it means that the lesion has entered the late stage, suspicious cases of rotator cuff rupture, should bear shoulder X-ray, arthrography, CT examination MRI, ultrasound and arthroscopy will help to establish a diagnosis.

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