Elbow joint tuberculosis

　　The occurrence of tuberculosis of the elbow joint is caused by Mycobacterium tuberculosis infection, which is a secondary tuberculosis disease. The specific causes and mechanisms of its occurrence are described as follows.

　　1、发病原因

　　骨关节结核病和全身结核病一样其致病菌均为结核分枝杆菌。结核分枝杆菌只有人型和牛型结核菌是人类结核病的主要致病菌。结核分枝杆菌为抗酸性、不能运动的杆菌，其特点为对异烟肼敏感并能产生烟酸和过氧化氢酶。关节结核是一种继发性结核病，多继发于肺或肠结核，因外伤、营养不良、过劳等诱因，使机体内原有结核病灶内的结核杆菌活跃经血液播散侵入关节或骨骼，当机体抵抗力降低时，可繁殖形成病灶，并出现临床症状。

　　2、发病机制

　　结核杆菌不能直接侵犯骨和关节，因此骨关节病变几乎都是继发的，即通过身体原发病灶的结核杆菌进入血运而潜伏在骨或关节滑膜中仍具有活力，但被纤维组织包围，处于静止状态，一旦遇到身体过度劳累、营养不良或其他疾病的侵袭加上机体免疫力下降时，潜伏的结核杆菌迅速繁殖，突破纤维组织包围，炎症扩大而发病。

　　骨关节结核的临床病理过程可分为单纯骨结核、单纯滑膜结核和全关节结核三种类型。而临床上以肘关节全关节结核为居多，其次为单纯骨结核，其中以尺骨鹰嘴结核为主，肱骨外髁次之，而肱骨内髁结核少见。肘关节的单纯骨结核具有典型松质骨结核特点，以中心型为多见，边缘型少见。中心型即结核病变位于松质骨中心部，表现有炎症浸润、肉芽、干酪样物、脓液和小死骨。死骨吸收后形成空洞，其周围骨质轻度致密。边缘型即病变位于松质骨边缘部，此处血运丰富，死骨易被吸收，形成骨质缺损和脓肿。边缘型脓肿易穿破而进入关节内形成全关节结核。肘关节单纯滑膜型结核其病变发生于关节的滑膜，病变早期呈现肿胀、充血、炎症细胞浸润。关节内有浆液性渗液。晚期时滑膜肥厚为暗红色，滑膜表面有乳突样增生和结核结节、有干酪样坏死，关节腔内有脓性渗液。单纯骨结核和全关节结核，未得到有效治疗可破溃形成窦道，多发生于肘后方鹰嘴附近，同时发生混合感染。肘关节破坏严重时，可发生病理性脱位。当病变趋向治愈时，多发生非功能位的纤维强直或骨性强直。

　　Tuberculosis of the elbow joint can be complicated with diseases such as abscesses, fistulas, joint destruction, and joint swelling, and the specific complications are described as follows.

　　1, Abscesses and fistulas: Abscesses begin to accumulate in the joint area, sinking and flowing beneath the fascia and between tissues, and can be seen under the skin. Sometimes, abscesses break through the skin to form fistulas. The skin around the fistulas becomes eroded and dark purple due to the stimulation of pus.

　　2, Joint destruction: Early joint capsule lesions are widespread, pathological products accumulate within the joint, causing the joint to swell and extend, leading to joint destruction or dislocation, and restricted movement.

　　3. Joint swelling: due to the thickening of the synovium, the thickening and edema of the joint capsule, granuloma abscess, and caseous material, joint edema occurs with swelling. The skin of the joint area is pale.

　　4. Deformity: With the progression of the lesion, joint destruction occurs, dislocation occurs, surrounding joint abscesses form, and pressure may also be exerted on the already destroyed joint, causing deformity of the hand.

　　5. Complications such as fibrous rigidity or bony rigidity may occur during treatment.

　　Elbow joint tuberculosis has a slow onset, and systemic symptoms may manifest as symptoms of tuberculosis intoxication, and local symptoms may manifest as pain, swelling, dysfunction, abscesses, and fistulas, and its specific clinical manifestations are described as follows.

　　First, systemic symptoms

　　During the active phase of the lesion, symptoms such as low fever, night sweats, decreased appetite, weight loss, fatigue, and accelerated erythrocyte sedimentation rate can be seen, which are symptoms of tuberculosis intoxication; during the stationary phase, systemic symptoms are not obvious.

　　Second, local symptoms

　　1. Pain, swelling, dysfunction Early pain symptoms are mild, and symptoms are severe in full joint tuberculosis. Simple bone tuberculosis and synovial tuberculosis often worsen after fatigue and improve after rest, and are often neglected by patients. When the pain intensifies, it has developed into full joint tuberculosis. Swelling in simple bone tuberculosis is often limited to the focus area, simple synovial tuberculosis swelling can be seen around the joint, and it is more obvious at the posterior part of the elbow, easy to be discovered; in full joint tuberculosis, the elbow joint may appear 'diamond swelling'. Due to pain, the function of the elbow joint is limited, showing a slight flexion, which is more obvious in the late stage.

　　2. Abscesses, fistulas Late lesions often form abscesses, which break down to form fistulas, often occur around the olecranon, and may be complicated with mixed infection.

　　Elbow joint tuberculosis is a secondary lesion, and the key to prevention lies in the prevention and treatment of primary pulmonary and intestinal tuberculosis to reduce the incidence of bone and joint tuberculosis. For formed bone and joint lesions, the principle of early diagnosis and early treatment should be implemented to shorten the course of treatment, reduce disability, and reduce the recurrence rate.

　　In addition to active surgical treatment and anti-tuberculosis drug treatment, attention should also be paid to rest, immobilization, and nutrition.

　　During the active stage of elbow joint tuberculosis, the erythrocyte sedimentation rate tends to increase, white blood cells are normal or slightly increased, and there is often mild anemia. The positive rate of tuberculosis bacteria in sputum culture in untreated patients is about 70%, the positive rate of synovial fluid culture is about 40%, and typical lesions are found in pathological examination. In addition, the following auxiliary examinations are also included.

　　1. X-ray examination

　　In early cases, there may only be osteoporosis and soft tissue swelling. When the joint tuberculosis progresses to the full stage, there may be progressive narrowing of the joint space and bone corrosion at the joint margin. On X-rays, foci of bone tuberculosis can also be seen, which are generally large and more common at the olecranon and the outer epicondyle of the humerus. In later cases, there may be pathological dislocation, and in cases with secondary infection, there may be bone sclerosis.

　　2. CT examination

　　It can show the amount of effusion in the joint cavity, early discovery of bone tuberculosis foci and bone destruction at the joint margin, and in later cases, it can show the location and direction of cold abscesses.

　　3. MRI examination

　　It can be found earlier that there are abnormal signals of inflammatory infiltration in the bone.

　　Patients with elbow tuberculosis fever should be given palatable, easily digestible, and nutritious food. It is best for general patients to eat a variety of foods, avoid fad eating, so that various nutrients can complement each other and not be lacking. Milk, eggs, fish, green vegetables, and fruits can all be used. Properly match coarse and fine foods for consumption. Pay attention not to eat cold and raw foods.

　　The treatment of elbow tuberculosis can achieve good results with the cooperation of anti-tuberculosis drugs and combined surgical treatment. The specific treatment methods and prognosis are described as follows.

　　First, treatment

　　Due to the superficial position of the elbow joint, it is easy to expose, and under the cooperation of anti-tuberculosis drugs, surgical treatment can achieve good results, and most patients can retain nearly normal joint function.

　　1. Simple synovial tuberculosis can be treated by injecting anti-tuberculosis drugs into the joint. The affected elbow can be fixed in a flexed 90° rotation neutral position with a triangular bandage. For those with significant swelling and pain, intermittent fixation with a plaster splint can be used. Take off the plaster splint 1-2 times a day to allow appropriate movement of the affected limb before re-fixation with the plaster splint. After treatment, if the lesions gradually absorb and heal, nearly normal joint function can be retained. If there is no improvement or the condition worsens, a synovectomy should be performed in a timely manner.

　　The synovectomy of the elbow joint can be performed through the posterior approach or the lateral approach. The former is more commonly used, in addition to excising the synovium, it is also used for the removal of lesions and the excision of the elbow joint. The advantage of this approach is that the exposure is sufficient; the disadvantage is that the ulnar nerve must be freed, the triceps tendon must be cut, and the stability of the joint is greatly damaged. The advantage of the lateral approach is that it does not require the release of the ulnar nerve, does not require the cutting of the triceps tendon, and the damage to the joint stability is smaller; the disadvantage is that the exposure is not sufficient.

　　(1) Through the posterior approach of the elbow joint: Make an 'S' incision at the posterior part of the elbow joint. The triceps tendon is turned downward in a tongue-like manner. At the level of the elbow joint, incise the humerus medially and laterally towards the epicondyle, and cut the total extensor and flexor tendons from the medial and lateral epicondyles of the humerus, and strip them off outside the joint capsule, exposing the medial and lateral collateral ligaments, the annular ligament, and the joint capsule. Flex the elbow to 90° and cut the medial and lateral collateral ligaments, the annular ligament, the joint capsule, and the synovium to enter the elbow joint.

　　Excise the thickened synovial tissue at the posterior part of the humerus-ulna, humerus-radius, and superior ulna-radius joints, and scrape off the granulation tissue at the edge of the cartilage surface. Further flex the elbow to more than 120°, expose, and excise the synovial tissue in front of the elbow joint.

　　After rinsing and adding anti-tuberculosis drugs, suture the cut lateral collateral ligament, annular ligament, joint capsule, and triceps tendon. After the operation, fix the elbow joint at 90° with a plaster splint, remove the stitches after 2 weeks, and switch to a triangular bandage for suspension. Start functional exercises after 3 weeks.

　　(2) Through the lateral approach of the elbow joint: Make a lateral incision of the elbow joint. Strip the brachioradialis, the long extensor of the radial side of the wrist, and the total extensor tendon from the lateral epicondyle of the humerus and the subperiosteal area of the anterior epicondyle towards the front. In the lower part of the incision, strip the extensor carpi ulnaris forward, and then strip the origin of the supinator from the upper end of the ulna, the lateral collateral ligament of the humerus, and the annular ligament, and pull them forward. Perform钝性剥离in front and behind the elbow joint capsule, incise the anterior and posterior joint capsules, the lateral collateral ligament, and the annular ligament, thus entering the elbow joint. Excise the synovium in front and behind.

　　2. For simple bone tuberculosis without obvious central and marginal necrotic tuberculosis without invasive joint trend, non-surgical treatment can be adopted first. If the treatment does not improve or worsens, surgical treatment should be adopted in a timely manner. For those with obvious dead bone or lesions with invasive joint trend, excision of the lesion should be performed in a timely manner.

　　Surgical treatment adopts different incisions according to the location of the lesion. Olecranon tuberculosis can be treated with a straight incision at the posterior part of the olecranon, and after incising the periosteum, a round chisel can be used to open a window to fully display the bone lesion. For lesions close to the insertion of the triceps brachii tendon, the tendon can be longitudinally split, but it should be avoided to completely mobilize or cut the tendon. Cleanly excise the dead bone and other pathological tissues. For those with destroyed cartilage surfaces, the olecranon is excised, and the maximum excision limit is close to the level of the coronoid joint surface. Rinse, place anti-tuberculosis drugs, and suture the incision. Postoperative management is the same as synovectomy.

　　Tuberculosis of the humeral capitulum and trochlea can be treated by making a straight incision on the medial or lateral side of the lower arm, fully exposing the lesion, and thoroughly removing the lesion. Tuberculosis of the humeral trochlea is more common than that of the humeral capitulum. For those with destroyed articular surfaces, the capitulum can be completely excised. Postoperative management is the same as before.

　　3. For early-stage total joint tuberculosis lesions that are still progressing, excision of the lesion should be performed in a timely manner as long as there are no contraindications for surgery. The posterior approach can also be used. Excise the thickened and edematous synovial tissue, and then scrape the bone lesion clean. The cartilage should be excised to normal bone. For those with destroyed articular surfaces of the humeral trochlea and ulnar olecranon, excision can be performed, as long as the trochlear articular surface and the coronoid olecranon partial joint surface are intact, the joint can be preserved. Postoperative management is the same as synovectomy.

　　4. For late-stage total joint tuberculosis, surgical treatment should be adopted as long as there are no contraindications.

　　(1) Lesion removal and osteotomy: It is a relatively suitable treatment method for most adults. For children under 12 years of age, resection is generally not performed due to the fear of affecting the epiphyseal plate and causing developmental disorders. Osteotomy can preserve the humeral capitulum and trochlea, and the stability of the elbow joint after surgery is good. The general surgical approach is to use a posterior incision, enter the posterior part of the elbow joint, remove the lesion, and then remove the radius head, retaining the radial tuberosity to avoid affecting the attachment of the biceps brachii. When excising the upper end of the ulna, attention should be paid to preserving the coracoid process and part of the trochlea to avoid affecting the attachment of the anterior brachial muscle and triceps brachii. Finally, the capitulum and trochlea of the humerus are removed, retaining the medial and lateral epicondyles of the humerus, so that the lower end of the humerus after excision is in a fork shape. Rinse, place anti-tuberculosis drugs, and insert two Kirschner wires from the trochlea to the lower end of the humerus, leaving the needle tails outside the skin, leaving a gap of 1-1.5 cm between the bone ends. After surgery, the elbow joint function is exercised for 3 weeks with a plaster splint, and then the suture is removed, the needle is pulled out, and the elbow joint function is exercised. Start active flexion of the elbow joint, and hang it with a triangular bandage when not exercising.

　　(2) Elbow joint arthroplasty: For patients whose tuberculosis has been cured, the elbow joint has become rigid and is in a functional position of 90° to 100°, it is generally not necessary to perform surgery again. Patients with the following conditions can consider elbow joint arthroplasty - young and middle-aged patients with elbow stiffness not in a functional position requiring an active joint, who can persist in exercise after surgery, have good strength of the biceps brachii and triceps brachii muscles, and have good local skin conditions.

　　The operation method of elbow joint arthroplasty is similar to that of resection. The ankylosed joint is chiseled open, the radial head is excised, the distal end of the humerus and the superior end of the ulna are shaped as required, and the阔筋膜is wrapped around the distal end of the humerus and lined inside the olecranon. Internal fixation with Kirschner wires is used during the operation, and the postoperative management is the same as that of elbow joint resection, but more emphasis needs to be placed on functional exercise after the operation. Its range of motion is not better than that of cross excision, and the chance of pain and stiffness is actually more than that of the latter.

　　The method of elbow joint cross excision is simple and easy to perform, does not require the placement of foreign bodies, and has a good postoperative functional recovery, which is a relatively good surgical option. Caution should be exercised in artificial joint replacement surgery.

　　Elbow joint resection, arthroplasty, synovectomy, and local lesion resection of olecranon and humeral condyle tuberculosis, etc., as long as the postoperative elbow joint functional exercise is maintained, can restore the elbow joint to a better function. According to observation, the function will become better over time after the postoperative period.

　　5. Lesion excision and joint fusion surgery are relatively ideal surgical options for adult patients who must participate in heavy physical labor in order to restore the stability and strength of the elbow joint.

　　The general surgical approach is to use a posterior incision. After the removal of the focus, the radial head is excised, the remaining cartilage surface is excised, the humerus and the olecranon of the ulna are roughened and matched together, and the elbow joint is positioned at 90°. To promote joint ossification, bone grafting can be added. To maintain alignment, screws or crossed Kirschner wires can be used for internal fixation. The use of foreign bodies should be cautious to avoid the formation of sinus tracts due to recurrence of the lesion.

　　II. Prognosis

　　Inevitably, different degrees of functional impairment will occur after the treatment of elbow joint tuberculosis. The cure of advanced full-joint tuberculosis can lead to joint stiffness, and elbow joint arthroplasty can obtain a certain degree of elbow joint mobility but with less strength.