【Orthopedic Arthroscopy】Arthroscopic synovectomy

body position

The patient is generally in the supine position, or the lower limb on the operating side is slightly abducted, the knee joint is naturally hanging on the side of the operating bed, and the lower limb on the opposite side is placed flat on the operating table, a tourniquet is applied, and a routine disinfection towel is applied. And add a one-time waterproof sheet. The arthroscopic lavage system is connected, and the lavage solution is generally 3000ml of normal saline plus 1ml of 0.1% epinephrine, which can better maintain a clear visual field during the operation.

approach choice

1. Anterior lateral approach

The conventional knee flexion is 90°, located at the junction of 1cm on the lateral knee joint line and 1cm from the lateral border of the patellar tendon, that is, at the lateral knee eye. The incision is inserted with a rounded puncture cone and cannula, and the joint cavity is entered through the subcutaneous tissue, infrapatellar fat pad and joint capsule. This entrance is located above the lateral joint line, about 1 cm below the patella. If the entrance is too close to the joint line, the lateral half moon The anterior horn of the plate can be torn or damaged, or the arthroscopic insertion can pass under the lateral meniscus into the joint cavity. An entry position that is too high at the talar joint line will allow the arthroscope to enter the space between the femoral and tibial condyles, impairing visualization of the posterior horn of the meniscus and other posterior structures. If the arthroscope is inserted close to the edge of the patellar tendon, the arthroscope can penetrate the fat pad, affecting the visual field and making the operation difficult.

1. Anterior and lateral approach

The conventional knee flexion is 90°, located at the junction of 1cm on the lateral knee joint line and 1cm from the lateral border of the patellar tendon, that is, at the lateral knee eye. The incision is inserted with a rounded puncture cone and cannula, and the joint cavity is entered through the subcutaneous tissue, infrapatellar fat pad and joint capsule. This entrance is located above the lateral joint line, about 1 cm below the patella. If the entrance is too close to the joint line, the lateral half moon The anterior horn of the plate can be torn or damaged, or the arthroscopic insertion can pass under the lateral meniscus into the joint cavity. An entry position that is too high at the talar joint line will allow the arthroscope to enter the space between the femoral and tibial condyles, impairing visualization of the posterior horn of the meniscus and other posterior structures. If the arthroscope is inserted close to the edge of the patellar tendon, the arthroscope can penetrate the fat pad, affecting the visual field and making the operation difficult.

3. Anterior median approach

Between the anteromedial and lateral entrances, it is located at the center of the patellar tendon 1 cm below the tip of the patellar tendon. If there is an abnormal increase in the Q angle, knee valgus, etc., it should be properly inward; when encountering a high or low patella, the height of the entrance should be adjusted appropriately. , as far as possible into the level of the intercondylar, the entrance is slightly higher or lower will affect the operation. There is no obvious damage to the patellar tendon after the operation through this mouth, but the in and out must pass through the fat pad, and anterior knee pain may occur after the operation.

4. Lateral-superior approach

The lateral border of the quadriceps tendon is located 2.5 cm above the lateral superior corner of the patella. Using the upper edge of the patella as a sign, push the patella outward to find out the patellofemoral joint space, and place the index finger on the upper edge of the patella, about the junction of a transverse finger on the upper edge of the patella and the patella joint space. The entrance is The most common route for placing an arthroscopic perfusion tube.

5. Posterior medial approach

The entrance is located behind the medial collateral ligament, 1cm on the posteromedial joint line, and 1cm behind the border of the posterior medial condyle of the femur, that is, the small triangle between the posterior and medial borders of the medial femoral condyle, and can be palpated with the knee flexed at 90°. When using this approach, care should be taken to prevent damage to the popliteal blood vessels and nerves. When positioning, the knee joint should not be filled, and the knee should be flexed 90°. When puncturing, the knee joint should be filled, and the blunt cannula core should be punctured from the top to the bottom. If this inlet is to be used during the operation, a long needle can be used to puncture after positioning. If there is liquid outflow, indicating that the needle has entered the joint, the cored cannula can be punctured and inserted along the puncture needle and its running direction. The structure of the medial chamber.

6. Posterolateral approach

In 90° flexion position, the intersection of the upward extension line of the posterior border of the fibular head and the posterior border of the femoral shaft, namely the lower border of the iliotibial band, the upper border of the biceps femoris tendon and the posterolateral border of the lateral femoral condyle, the posterolateral 2cm above the joint. When entering directly through this entrance, the skin incision should be positioned and poked under the condition that the joint cavity is not filled, and then the joint cavity should be filled with a cored cannula. The procedure for puncture placement of the cannula is the same as for the posteromedial access procedure to prevent damage to the popliteal vessels and nerves. The entrance is mostly used for the inspection and operation of the structure of the posterior joint cavity.

excision method

Partial synovectomy can be accomplished through anterior-medial approach and anterior-exterior approach, and total synovectomy includes 20% resection of the synovial membrane of the posterior joint cavity, which must be completed through 6 approaches. Before synovectomy, the joint cavity should be explored in detail, starting from the suprapatellar capsule, through the medial and lateral recesses, the tibiofemoral joint, around the medial and lateral meniscus, around the cruciate ligament, and finally the posterior joint cavity. Following the above sequence of synovectomy can avoid omissions and make the vision of the joint cavity clearer and clearer.

The first step is to observe the microscope through the anterolateral approach. The synovial membrane at the distal end of the suprapatellar capsule and the medial recess is removed through the lateral-superior approach or the anterior-medial approach. For observation and surgery, the synovium at the proximal end of the suprapatellar capsule is far away from the anterolateral approach, so the observation and anterolateral approach can be used instead.

The second step is to remove the synovium of the tibiofemoral joint cavity. Conventional anteromedial and anterolateral approaches can accomplish this step, including the intercondylar fossa, the edge of the meniscus and below, the synovium on the surface of the fat pad, and a small portion of the synovium in the posterior joint cavity. After trimming or excision, the posterior part of the meniscus body has a better field of vision when the knee joint is nearly straight, and observation surgery should be performed in this position. The synovium below the meniscus and at the junction of the cartilaginous synovium can be excised with a curved planer. For the synovium at the outer and medial posterior edges of the meniscus, the planer can be used from the anterior medial and anterolateral sides. membrane.

The third step is to remove the synovium of the posterior joint cavity. After the intercondylar fossa was cleaned, a 70° scope was advanced from the anterior to the medial, through the lateral aspect of the anterior cruciate ligament, between the medial side of the lateral femoral condyle and the posterior angle of the lateral meniscus, into the posterolateral joint cavity, and then entered the planer from the posterolateral approach to remove the posterolateral The synovium of the joint cavity; on the contrary, through the anterior-lateral approach, the medial posterior cruciate ligament, the lateral side of the medial condyle of the femur and the posterior angle of the medial meniscus enter the posterior medial joint cavity, and the planer is inserted through the posterior medial approach to remove the posterior medial joint cavity. synovial membrane. In addition, another method can also complete the total synovectomy of the posterior joint cavity. The classical approach is used for arthroscopic observation. The planer is used to remove the synovial membrane between the cruciate ligament and the femoral condyle as much as possible through the anterolateral or anteromedial approach. There is a certain resistance in front of the cavity, and there is a sense of breakthrough when sliding into the posterior joint space; enter the arthroscope through the posterior medial or posterior external approach to observe the corresponding posterior space, plan the posterior synovium, and then enter the mirror through the posterior approach, the classic approach A planing knife was used to plan the posterior synovial membrane between the femoral condyle and the cruciate ligament, observe the residual synovial membrane in the posterior joint cavity, and then enter the residual synovial membrane from the rear for resection.

It should be noted that the planer should not be directed towards the posterior joint capsule for too long, and the attractive force of the planer should not be too large, so as not to damage the blood vessels and nerves of the popliteal region. The author reminds that total synovectomy is not a simple expansion of partial synovectomy. In particular, attention should be paid to clearing the synovium in the posterior joint cavity to avoid damage to blood vessels and nerves. The technical requirements are high and it is not suitable for beginners.

Postoperative monitoring and management

Some surgeons believe that there is less joint bleeding after synovectomy, and drainage may not be placed. The author's experience is that patients with total synovectomy have more oozing blood, and some patients have as much as 500ml. It is recommended to place a closed negative pressure drainage bottle. After surgery, the affected limbs were routinely bandaged with thick and large burn gauze and compressed with elastic bandages. Postoperative oral non-steroidal anti-inflammatory drugs can reduce swelling, relieve pain, and increase the range of motion of joints. Generally, hemostatic drugs are not used, and anticoagulants (low molecular weight heparin or rivaroxaban) should be added in patients over 50 years old. Prophylactic use of antibiotics should be discontinued within 24 hours after surgery. Quadriceps isometric exercises, ankle pump exercises, and straight leg raises can be started the day after surgery. On the second day after the operation, the knee joint flexion and extension activities were gradually performed, the wound was opened for dressing changes, the incision condition and drainage volume were observed, and the negative pressure drainage tube was removed. The sutures are removed two weeks after the operation. Generally, the range of motion of the joint is required to reach 90° within 1 week, and more than 120° within two weeks. It should be noted that, according to different etiologies, corresponding treatment should be adopted. For example, patients with rheumatoid arthritis should be treated with anti-rheumatic drugs, and patients with pigmented villonodular synovitis should be treated 1 month after surgery. Knee joint local radiotherapy, total dose 1200cGy, 10 times.

common after surgery

Prevention and management of complications

1. Infection

Including access incision infection and intra-articular infection, although arthroscopic surgery is less traumatic, rapid operation, and irrigation of perfusate, which significantly reduces the infection rate, there is still the possibility of infection. Current studies have shown that the incidence of infection after arthroscopy is 0.5% to 0.8%, and the principle of asepsis should be strictly followed to prevent infection. Preoperative disinfection should be thorough. For lower extremity surgery, the entire lower extremity must be strictly sterilized from the part below the tourniquet to the toes. It is not possible to sterilize the part of the knee and its surroundings according to open surgery, and then wrap the foot with a sterile medium, because the seepage of the liquid to the outside can cause the foot to be sterilized. The sterile towel covering the feet is wet, and waterproof measures should be added after the operation table is laid in the polluted operating area. Generally, a disposable sterile waterproof sheet is used to lay another layer. If the operation time is long, antibiotics can be added during the operation. Rapid operation, shortening the operation time, thorough rinsing, effective intraoperative hemostasis, and prevention of postoperative intra-articular hematoma are also effective measures to prevent infection. At the same time, the surgeon should also take sterile waterproof measures and wear waterproof clothing and water shoes. After the operation, the white blood cell count is increased, the skin temperature of the affected limb is increased, and the blood C-reactive protein and erythrocyte sedimentation rate are significantly increased. Bacterial culture and drug susceptibility test should be done quickly, and antibiotics should be used empirically. antibiotic. If there is no improvement after 3 days of antibiotic treatment, emergency arthroscopic lavage and drainage can be performed.

2. Postoperative bleeding and intra-articular hematoma

It is more common in operations with more intraoperative soft tissue treatment, such as arthroscopic release of the lateral retinaculum of the knee joint, release of adhesions, and synovectomy. The use of high-frequency electrosurgery and radiofrequency vaporizer for surgery and intraoperative hemostasis can effectively prevent postoperative bleeding. At the same time, when this type of hand is used for a long time, a negative pressure drainage tube should be placed in the joint cavity to drain the accumulated blood. After surgery, it is more effective to apply gauze layer-by-layer pressure, braces to fix and brake, and local cold compresses. For patients with hemophilic arthritis, attention should be paid to timely supplementation of coagulation factors to normal levels before and after surgery.

3. Lower extremity venous thrombosis and pulmonary embolism

Deep vein thrombosis of lower extremities can occur after arthroscopy. AANA statistics report that the incidence rate is 0.1%. Some cases have pulmonary embolism, which eventually leads to death. Clinicians should attach great importance to it. When the lower extremity is obviously swollen, blood vessel B-ultrasound can be used to confirm the diagnosis. In terms of prevention, the use time of the tourniquet should be shortened during the operation, and the longest should not exceed 90 minutes. Early postoperative activities of the affected limb and ankle pump exercises are encouraged. In a 50-year-old patient, use low molecular weight heparin or rivaroxaban to prevent thrombosis.

4. Tourniquet paralysis

It is related to the use of the tourniquet for too long. If the tourniquet is used for more than 90 minutes, there is a high incidence of tourniquet paralysis. It is more likely to occur when the tourniquet is loosened and then continued to apply. Muscle and nerve organic damage and difficult to recover. Therefore, effective preventive measures can shorten the tourniquet time. The first tourniquet should not stand for more than 90 minutes. The surgeon should try to complete the operation during this period.

5. Joint adhesion and stiffness

Joint stiffness can occur after arthroscopy. Early postoperative functional exercise rehabilitation can effectively avoid joint adhesion. If the adhesion is serious and the stiffness of the knee obviously affects the movement, arthroscopic release can be performed.

Clinical effect evaluation

The synovectomy of rheumatoid patients has a certain preventive protective effect on the joints, and the patients can obtain satisfactory results, and the joint pain and inflammation can be significantly relieved. Therefore, for patients with persistent joint swelling and hyperplasia and X-ray manifestations of stage 0 to I, medical treatment for 6 to 12 months is ineffective. Only patients with synovial lesions that do not affect the joint space should actively undergo surgery to treat pigmented villous nodules. There are two types of synovitis, diffuse and localized. For limited patients, studies have shown that the postoperative effect is better. No matter whether open surgery or arthroscopic surgery, there is no recurrence after local surgery; for diffuse patients, postoperative recurrence is easy, and the recurrence rate is 9% to 14%. After 1 month of local radiotherapy, the recurrence rate can be greatly reduced. After total synovectomy for hemophilic arthritis, it has been reported in the literature that it can reduce the frequency of joint bleeding, alleviate the condition and slow down the progression of the disease. In patients with synovial chondromatosis, arthroscopic surgery is more effective than simple loose body removal.

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