[Orthopedic Arthroscopy] Arthroscopic synovectomy

Body position

The patient is generally placed in a supine position. You can also slightly abduct the lower limb on the operative side when the patient is in the supine position, hang the knee joint naturally on the side of the operating bed, place the contralateral lower limb flat on the operating bed, apply a tourniquet, and apply routine disinfection and draping. And add a disposable waterproof sheet. Connected to the arthroscopic lavage system, the lavage fluid is generally 3000 ml of normal saline plus 1 ml of 0.1% epinephrine, which can better maintain clear vision during the operation.

Access selection

1. Anterolateral approach

The conventional knee flexion position is 90°, located at the junction of 1cm from the lateral knee joint line and 1cm from the lateral edge of the patellar tendon, which is the lateral knee eye. Use a round-head puncture cone and cannula to insert into the incision, and enter the joint cavity through the subcutaneous tissue, infrapatellar fat pad and joint capsule. This entrance is located above the lateral joint line and about 1cm 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 injured, or the insertion of the arthroscope can penetrate the joint space from beneath the lateral meniscus. If the entrance position is too high from the joint line, the arthroscope will enter the gap between the femoral and tibial condyles, affecting the observation 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 field of view and making the operation difficult.

2. Anteromedial approach

The entrance position is similar to the anterolateral approach, located at the junction of 1 cm from the medial knee joint line and 1 cm from the medial edge of the patellar tendon, which is the medial knee eye. The above two entrances are the most commonly used entrances. The conventional positioning method is based on the method of foreign authors. A 1cm lateral opening to the patellar tendon may be too large. In our country, a 0.5cm lateral opening is appropriate. In addition, it should also be based on the patient's age, body shape, and limb fatness. Factors such as thickness and thickness should be considered for positioning. The author’s experience is that at the medial and lateral knee joints, before the infusion fluid fills the joint cavity, the incision site should be at the deepest point on the medial and lateral side of the anterior patellar tendon of the knee joint. After the infusion fluid fills the joint cavity, the incision site should be the fullest point.

3. Anterior midline approach

Between the anterior medial and lateral entrances, located in the center of the patellar tendon 1cm below the tip of the patellar tendon, if there is an abnormal increase in the Q angle, knee valgus, etc., the entrance should be appropriately moved inward; when encountering a high or low patella, the height of the entrance should be adjusted appropriately , enter the intercondylar space as horizontally as possible. A slightly higher or lower entrance will affect the operation. Surgery through this port will not cause obvious damage to the patellar tendon, but the fat pad must be passed in and out, and anterior knee pain may occur after the operation.

4. Upper lateral approach

It is located on the outer edge of the quadriceps tendon 2.5cm above the lateral superior corner of the patella. Using the upper edge of the patella as a mark, push the patella outward to find out the patellofemoral joint space. Place the index finger on the upper edge of the patella and locate it at the junction of a transverse finger on the upper edge of the patella and the patellofemoral joint space. The entrance is The most common approach for placement of arthroscopic irrigation lines.

5.Posteromedial approach

The entrance is located behind the medial collateral ligament, 1 cm behind the posteromedial joint line, and 1 cm behind the posterior medial edge of the femoral condyle, that is, the small triangle area between the posterior and medial edges of the medial femoral condyle. It can be touched by bending the knee 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 bent at 90°. During puncture, the knee joint should be filled, and the blunt-tipped cannula core should be inserted obliquely from upward to inward. If this entrance is to be used during the operation, you can puncture it with a long needle after positioning it. If there is liquid flowing out, it means that the needle has entered the joint. Then you can puncture and insert the cored cannula along the site and direction of the puncture needle. You can observe through this entrance. The structure of the inner chamber.

6.Posterolateral approach

With the knee flexed 90°, the intersection point between the upward extension line of the posterior edge of the fibular head and the posterior edge of the femoral shaft, that is, between the lower edge of the iliotibial band, the upper edge of the biceps femoris tendon and the posterior and outer edge of the lateral femoral condyle, and between the posterior and lateral edges of the femoral condyle. 2cm above the joint. When entering directly from 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 perfusion and then a cored cannula should be inserted. Move it medially and downward toward the posterior condyle, touch the surface, and then move inward to enter the joint cavity. The same procedures for puncture placement of cannulae as for posteromedial access operations should be performed to prevent damage to the popliteal vessels and nerves. This entrance is mostly used for inspection and surgery of structures in the posterior joint cavity.

Excision method

Partial synovectomy can be completed through the anteromedial approach and the anterolateral approach. Total synovectomy includes the resection of 20% of the synovium in the posterior joint cavity, and must be completed through 6 approaches. Before synovectomy, the joint cavity should be explored in detail, starting from the suprapatellar bursa, passing through the medial and external recesses, the tibiofemoral joint, around the medial and lateral menisci, around the cruciate ligament, and finally observing the posterior joint cavity. Following the above sequence for synovectomy can avoid omissions and provide a clearer view of the joint cavity.

The first step is to observe the microscope through the anterolateral approach, and resect the synovium at the distal end of the suprapatellar bursa and the medial recess through the superior lateral approach or the anteromedial approach. The lateral recess can be removed from the anterolateral recess due to the higher femoral lateral condyle. Both the superior and lateral approaches are used for observation and surgery. The synovium at the proximal end of the suprapatellar bursa is far away from the anterolateral approach. Therefore, the superior lateral approach can be used for observation and the anterolateral approach can be used for planing.

The second step is to remove the synovial membrane of the tibiofemoral joint cavity. This step can be accomplished through the conventional anteromedial and anterolateral approaches, including the intercondylar fossa, the meniscus edge and below, the synovium on the fat pad surface, and a small portion of the synovium in the posterior joint space. If the meniscus is eroded, it is necessary to For trimming or resection, the posterior part of the meniscal body has a better view when the knee joint is close to extension, and the operation should be observed in this position. The synovium below the meniscus and at the junction of the cartilage and synovium can be resected with a curved planer. For the synovium on the outer and rear edges of the meniscus and the inner and rear edges, the planer can be used from the anterior medial and anterolateral sides. The synovium in the popliteal muscle bursa can also be resected. membrane.

The third step is to remove the synovial membrane in the posterior joint cavity. After the intercondylar fossa is cleaned, enter the 70° mirror from the anterior medial approach and enter the posterolateral joint space through the lateral aspect of the anterior cruciate ligament, the medial aspect of the lateral femoral condyle and the posterior corner of the lateral meniscus. The synovium of the joint cavity; on the contrary, enter the posterior internal joint cavity through the anterior and external scope, enter the posterior internal joint cavity through the medial side of the posterior cruciate ligament, the lateral side of the medial femoral condyle and the posterior corner of the medial meniscus, and then use a planer through the posteromedial approach to resect the posterior internal joint cavity. synovial membrane. In addition, another method can also complete the total synovial resection of the posterior joint cavity.The classic approach is used for arthroscopic observation. The planer is used to remove as much synovial membrane as possible between the cruciate ligament and the femoral condyle through the anterolateral or anteromedial approach. This facilitates the arthroscope to enter the posterior joint cavity through this point and the arthroscope to enter the posterior joint. 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 posteromedial or posterolateral approach to observe the corresponding posterior space, plan the posterior synovium, and then enter the mirror through the posterior approach, the classic approach The planer is used to plan the posterior synovium between the femoral condyle and the cruciate ligament and observe the residual synovium in the posterior joint cavity, and then enter the residual synovium from the rear for resection.It should be noted that the planer should not be directed toward the posterior joint capsule for too long, and the attractive force of the planer should not be too large to avoid damage to the popliteal blood vessels and nerves. The author reminds that total synovectomy is not a simple extension of partial synovectomy. In particular, attention must be paid to clearing the synovium in the rear joint cavity to avoid damage to blood vessels and nerves. It requires high technology and is not suitable for beginners.

Postoperative monitoring and management

Some surgeons believe that joint bleeding after synovectomy is less and drainage is not necessary. The author's experience is that patients with total synovectomy bleed more, up to 500ml in some patients, and it is recommended to place a closed negative pressure drainage bottle. After surgery, the affected limb is routinely wrapped with thick and large burn gauze and compressed with an elastic bandage. Postoperative oral nonsteroidal anti-inflammatory drugs can reduce swelling, relieve pain, and increase joint range of motion. Generally, hemostatic drugs are not used. Patients over 50 years old are given additional anticoagulants (low molecular weight heparin or rivaroxaban). If prophylactic antibiotics are used, they should be stopped within 24 hours after surgery. Quadriceps isometric exercises, ankle pump exercises, and straight leg raise functional exercises can be started the day after surgery. On the second day after the operation, you can gradually perform knee joint flexion and extension activities, open the wound and change the dressing, observe the incision condition and drainage volume, and remove the negative pressure drainage tube.The sutures are removed two weeks after surgery. Generally, the joint range of motion is required to reach 90° within one week and exceed 120° within two weeks. The range of motion should be restored to the preoperative range four weeks after surgery. Special attention should be paid to the fact that corresponding treatments should be adopted according to different causes. For example, patients with rheumatoid arthritis should be treated with anti-rheumatic drugs, and patients with pigmented villonodular synovitis should be treated with anti-rheumatic drugs starting 1 month after surgery. Local radiotherapy of the knee joint, with a total dose of 1200cGy, was performed in 10 fractions.

Prevention and treatment of common postoperative complications

1. Infection

Including incision infection and intra-articular infection, although arthroscopic surgery has small trauma, rapid operation, and irrigation with perfusion fluid, which significantly reduces the infection rate, there is still the possibility of infection. Current research shows that the incidence of infection after arthroscopy is 0.5% to 0.8%. To prevent infection, the principle of asepsis must be strictly followed.Preoperative disinfection must be thorough. Lower limb surgery must strictly disinfect the entire lower limb from the part below the tourniquet to the toes. Open surgery cannot be performed to disinfect the knee area and surrounding areas before using sterile foot wraps, because liquid seepage to the outside can cause the foot to be sterilized. The sterile towel that wraps the feet will soak and contaminate the operating area. After the operating table is draped, waterproof measures must be taken. Generally, a layer of disposable sterile waterproof drape is used. If the operation time is long, antibiotics can be added during the operation as a preventive measure. Quick operation, shortened operation time, thorough flushing, effective hemostasis during the operation, and prevention of postoperative intra-articular hematoma are also effective measures to prevent infection. At the same time, the surgeon should also take sterile and waterproof measures and wear waterproof clothing and water shoes.After the operation, the white blood cell count increases, the skin temperature of the affected limb increases, and the blood C-reactive protein and erythrocyte sedimentation rate increase significantly. Bacterial culture and drug susceptibility testing should be done quickly. Antibiotics should be used empirically first, and sensitive ones should be selected after the drug susceptibility results are available. 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 surgeries that involve a lot of soft tissue handling during surgery, such as arthroscopic release of the lateral retinaculum of the knee joint, adhesiolysis, synovectomy, etc. The use of high-frequency electrosurgery and radiofrequency vaporizer for surgery and intraoperative hemostasis can effectively prevent postoperative bleeding. At the same time, a negative pressure drainage tube should be placed in the joint cavity during this type of hand lengthening to drain out the accumulated blood. Measures such as layer-by-layer compression of gauze for large burns after surgery, fixed braking of braces, and local cold compress are more effective. 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 the lower limbs can occur after arthroscopy. AANA statistics report that its incidence rate is 0.1%. Some cases develop pulmonary embolism and eventually lead to death. Clinicians should pay great attention to it. When the lower limbs are obviously swollen, vascular B-ultrasound examination can be performed to confirm the diagnosis. In terms of prevention, the tourniquet usage time should be shortened during the operation to no more than 90 minutes. Early postoperative activities of the affected limbs and ankle pump exercises are encouraged. For patients older than In a 50-year-old patient, low molecular weight niheparin or rivaroxaban was used to prevent thrombosis.

4. Tourniquet paralysis

It is related to the use of tourniquet for too long. Tourniquet paralysis is more likely to occur in those who use the tourniquet for more than 90 minutes. It is more likely to occur when the tourniquet is loosened and then applied again. In mild cases, postoperative paralysis can recover within 3 days to 3 weeks. In severe cases, tourniquet paralysis will occur. Muscles and nerves are damaged and difficult to recover from. Therefore, effective preventive measures can shorten the tourniquet time. The tourniquet should not be applied for more than 90 minutes for the first time. The surgeon should try to complete the operation during this period. If there is really difficulty, wait at least 15 minutes before applying the tourniquet.

5. Joint adhesion and stiffness

Adhesions and stiffness may occur after arthroscopy. Proper functional exercise rehabilitation in the early postoperative period can effectively avoid joint adhesions. If the adhesion is severe and the stiffness of the knee joint significantly affects movement, arthroscopic release surgery may be possible.

Clinical effect evaluation

Synovectomy in rheumatoid patients has a certain preventive and protective effect on joints. Patients can obtain satisfactory results and joint pain and inflammation are significantly relieved. Therefore, for patients with persistent joint swelling and hyperplasia whose X-ray manifestations are stage 0 to I,Patients with 6 to 12 months of medical treatment ineffective and only synovial lesions that do not affect the joint space should undergo active surgical treatment for pigmented villonodular synovitis, which is divided into two types: diffuse and localized. For patients with localized disease, studies have shown that the postoperative results are better. No matter open surgery or arthroscopic surgery, there is no recurrence after local surgery. For patients with diffuse disease, recurrence is easy after surgery, with a recurrence rate of 9% to 14%. Surgery is recommended. Local radiotherapy one month later can greatly reduce the recurrence rate.After total synovectomy for hemophilic arthritis, literature reports that it can reduce the number of joint bleeding, relieve the condition and slow down the progression of the disease. Patients with synovial chondromatosis undergo arthroscopic surgery, and the surgical effect is better than simple loose body removal.