Artificial knee joint unicondylar replacement

Single-sputum surgery is the application of MIS minimally invasive techniques to reduce pain, early activity, reduce hospital stay, and rapid recovery, and restore function very early. During the operation, it is forbidden to correct the alignment line too much, but a slight lack of line will have a better effect. Due to excessive correction, the stress will be transferred to the contralateral space, which will lead to the failure of the operation. Treating diseases: traumatic arthritis Indication Artificial knee joint replacement is applicable to: 1. Single room osteoarthritis or traumatic arthritis. 2. Old fractures of the humerus or platform. 3. Knee / valgus deformity <15 °. 4. Only use bone cement technology. Contraindications 1. Rheumatoid arthritis. 2. Too fat. 3. Knee / valgus deformity > 15 °. 4. Two or three compartments of the lesion. Surgical procedure Expose joint According to the surgeon's habits, incision in the knee flexion or knee extension, the anterior medial incision, from the midline of the humerus slightly, cut down 7 ~ 12cm, straight to the base of the nodule, use scissors to cut the switch capsule along the inner edge of the humerus, The starting point is about the level of the humerus, or slightly closer to the end or distal end, but do not touch the medial femoral muscle, down to the joint line 3cm, remove the synovial fat pad and meniscus. If necessary, make a horizontal or oblique incision at the distal end of the femur, 1.5 cm long, which can be T-shaped with the original incision. Do not loosen other soft tissues at this time. Intra-articular debridement and careful examination to remove the intercondylar fossa to avoid impact with the tibial spine or cruciate ligament, while removing the surrounding epiphysis to remove the barrier to the bilateral collateral ligament and joint capsule. In the patient's inversion, the epiphysis can often be found on the outside of the tibial spine, and the chapped gauze is protected with a wet gauze. At different flexion degrees, the patellofemoral joint, the lateral space and the anterior cruciate ligament were examined. If the lateral septum had obvious cartilage damage, a total knee replacement was required. 2. The distal part of the femur Flex the knee 20 ° ~ 30 ° (do not turn the humerus), push the humerus to the outside, find the insertion of the femur osteotomy guide, 1cm in front of the starting point of the posterior cruciate ligament (just in front of the intercondylar notch). A hole was drilled with an 8 mm drill or a pointed cone, and only the cancellous bone at the distal end of the femur was drilled, and the intramedullary adipose tissue was aspirated by a suction device for decompression. Insert the introducer along the direction parallel to the anteroposterior and lateral positions of the femur. Due to the wide width of the distal femoral shaft, the resistance encountered when inserting the guide rod is very small. The introducer rod is divided into two types, the long rod and the short rod. The long rod can be correctly measured. If the artificial hip surgery or the femoral deformity has been performed on the side, the short rod can be used instead. The introducer is divided into left inner/right outer and right inner/left outer. Install the universal handle, insert the femoral introducer, when it touches the femoral articular surface, master its rotation, the posterior edge of the introducer should be parallel to the humeral surface, that is, the long axis of the vertical tibia, the purpose is to cut after parallel Good shin bone. The knee can be extended to adjust the position of the introducer. To ensure that the working face of the introducer is completely flush with the femoral articular surface, there is no soft tissue incarceration, and a fixing nail is inserted into the posterior flange of the introducer. The intramedullary femoral distal osteotomy has 6° and 8° osteotomy angles, generally 6°, and the distal femur is osteotomy. 3. The humerus part The guide stem can be adjusted to the desired length and tightened by screws. The distal end of the guide is located 5 to 10 mm inside the midpoint of the inner and outer iliac line. The tip should point to the 2nd metatarsal and then surrounded by a spring arm or forceps. The crotch is fixed. Loosen the cadaver screw, adjust the proximal end of the sac to the proximal end of the tibial tuberosity, and place the osteotomy groove in the desired position. The long axis of the stem should be inside the tibial tuberosity, which is equivalent to the midpoint of the intercondylar carina. Move the cadre in the sagittal plane so that it is parallel to the long axis of the humerus and tighten the screws to ensure correct bone cutting. If the crotch is too thick, adjust the cadres to match them. Insert the tip of the 2mm deep-cut indicator into the top of the tibial cutter and place the arm of the indicator at the lowest point of the tibial plateau and secure it. It indicates that the 2mm bone is cut under the tip of the indicator arm. Under the premise of not damaging the anterior cruciate ligament, the sagittal universal cutting indicator is correctly placed. The closer to the iliac bone spine, the better the nail is inserted into the osteotomy machine. The platform is fixed at 0°. An electric knife was used to make the sagittal section of the humerus surface, and the reaming position and the extension position were repeatedly checked. After the stud was fixed, a concave humeral spacer (planar downward) was placed on the humeral osteotomy, and the varus valgus and posterior tibial inclination were tested according to the tibia axis, and then the second fixation nail was inserted. If necessary, you can re-insert the tibia bone thickness tester and measure again. If the thickness is not enough, remove the tester and move the nail to +2, +4, +6 and try again. This can increase the thickness of 2mm, 4mm, 6mm. After determining the thickness of the bone, fix it with nails. The inside of the pull hook is inserted to protect the medial collateral ligament, and the reciprocating saw is used for sagittal cutting. 4. Trimming the femur The femoral prosthesis has a total of 7 sizes and corresponding measurement indicators, and the handle is connected to the selected indicator and tightened. The indicator is placed on the distal surface of the femur, and the foot rests into the joint cavity and is shackled. There is still a gap of 1 to 2 mm between the leading edge (ie, the upper edge) and the bone surface. Insert the femoral introducer, measure the size of the bone, and fix it. Use the oscillating saw to cut off the posterior and posterior oblique angles of the femur and make the pile. 5. Trimming the humeral part Cut the residual meniscus and callus, especially the epiphysis of the medial collateral ligament, place the humeral measure on the cut surface, with the straight edge attached to the sagittal section and test the sagittal section edge, as measured The handle is 90° in the coronal plane, indicating that the sagittal osteotomy is correct and the humerus is piled. Select a measurer that covers the humeral section in both the anterior/posterior/inner and outer directions. The size of the sacral slice can be used to check the size of the meter to be selected. Note that the measuring device does not protrude from the edge of the cut bone, and there is strong cortical support around it, then remove the measuring device and remove the soft tissue residue in the ankle. 6. Prosthesis model reset The forceps retractor can be removed and the femoral prosthesis mold and the tibial fixator mold and the articular surface mold can be used for resetting. The concave articular surface spacer can replace the fixed plate mold and the articular surface mold. The T-shaped handle is placed on the femoral mold, the femoral mold is guided around the humerus, and the knee is placed in the deep flexion. The long post is placed first, the knee is slightly bent, and the prosthetic mold is rotated behind the humerus. Deeply bend your knees to complete the placement. When placing the tibial articular mold, remove the 27mm screw first. If necessary, you can repair the screw hole slightly. After all the molds are in place, check the rotation and alignment stability. When the flexion position is extended, the femoral prosthesis should always be in the middle of the humerus, otherwise the femoral mold should be repositioned after adjustment. The sacral or concave septum of the tibial joint does not interfere with each other in the full flexion position, avoiding choking, otherwise the stress will be transmitted to the contralateral space. The soft tissue tension was examined at the extensional flexion position and tested with a 2 mm tension gauge to ensure that the flexion and extension gap was not tight. The correct thickness of the prosthesis is based on the filling of the joint space, but not too tight, otherwise it will give too much stress to the collateral ligament. According to the rules, when the knee is straight and there is no soft tissue peeling, the joint gap should only be opened 2mm after being subjected to external force. This is also required when knees are 90°. Too tight a flexion position will limit knee flexion, and when the femoral prosthesis is rolled back, it will cause the tibial prosthesis to rise forward. If there is a flexion position, it can be solved by using a thin joint surface or increasing the posterior tilt of the tibia. 7. Place the prosthesis (1) Application of metal tibial prosthesis: first placed into the metal chassis, the knee should be externally flexed when placed. Before the bone cement, a wet sterile gauze can be placed in the back of the humerus to cover the overflow. Bone cement. First put the bone cement and then press the humeral prosthesis chassis: 1 Press and release the back of the prosthesis; 2 Squeeze the front of the prosthesis and squeeze out excess bone cement; 3 remove the stuffed gauze from the back of the humerus; 4 scrape off the residual bone cement. Then, the knee is bent to the femoral bone, and then the femoral prosthesis is placed. The long post is inserted first, then the knee is placed in the middle flexion position, and the orientation of the prosthesis is adjusted after the humerus, and then the knee is placed and inserted. Prosthesis. Insert the tension gauge again until the bone cement hardens. Before placing the patella articular surface, remove all residual bone cement, put its engraving face down, and slide the trailing edge of the polymer polyethylene plastic joint surface into the rear lip of the chassis, that is, the opposite side of the spring, and then press it in. The plastic joint surface is in place so that the spring securely locks the articular surface. (2) Apply a full-sacral humeral prosthesis: a knee with external flexion and a piece of wet gauze at the back of the humerus to retain the spilled bone cement. Press the bone cement on the humeral surface and press the full plastic prosthesis; 1 put the posterior part of the prosthesis first, put the pressure on it; 2 press the front part to squeeze out the excess bone cement; 3 remove the humerus Part of the gauze; 4 scrape off all excess bone cement. Be careful not to use a striker to strike a full plastic prosthesis. Place the femoral prosthesis as described above for the femoral prosthesis, insert the tension gauge to balance the flexion and extension gap, and insert the measurement piece into the straight knee until the cement hardens. complication Thromboembolism Deep vein thrombosis is one of the most serious complications after knee arthroplasty, which can lead to pulmonary infarction and life-threatening. Clinical diagnosis can be performed by venography or Doppler ultrasonography, and the accuracy of venography is higher. For the prevention of deep vein thrombosis, anticoagulants such as low molecular weight heparin sodium and mechanical therapy such as antithrombotic and plantar venous pumps can be used. 2. Infection Infection is one of the most terrible complications of artificial joint replacement and the most important cause of early failure of knee replacement. The bacteria causing the infection are mainly Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus, Micrococcus and the like. Prevention of infection is more important: skin preparation in the operating room, reduction of preoperative hospital stay, treatment of potential infections in other parts of the body, prevention of antibiotic use, use of laminar flow operating rooms, reduction of the number of personnel in the operating room and movement of personnel, surgery The person wears double gloves, reduces the operation time, and washes the wound with a large amount of saline before closing the incision. Vancomycin can be used when the patient is allergic to penicillin. The main symptom of infection is pain. When the pain persists after the operation, or the pain is relieved, the knee joint function is good, and the pain occurs again, and the infection should be suspected. A reliable indicator for the diagnosis of infection after joint replacement is C-reactive protein, which peaks at 24 to 48 hours after surgery, and then gradually decreases, and returns to normal after 3 weeks. Bone and bone cement interface bone absorption occurred on the X-ray film, cystic changes. Puncture suction smear and bacterial culture are helpful for diagnosis, and can be repeated several times in order to increase sensitivity. Once diagnosed, the joint debridement can be used to preserve the prosthesis, but only a small number of patients are available: infections that occur within 4 weeks, or acute hematogenous disseminated infections, while the prosthesis is firmly fixed, but must be fixed during debridement. Replace the plastic liner. Otherwise, the joint should be thoroughly debrided, the prosthesis should be taken out, and the antibiotic cement spacer should be used. It is best to use a movable antibiotic bone cement placeholder. After infection control, the second phase of revision surgery, take out the antibiotic bone cement placeholder, thoroughly debride, and then choose the appropriate prosthesis for renovation. The interval between the two operations should be longer than 6 weeks. The antibiotics should be stopped for more than 2 weeks. The erythrocyte sedimentation rate and C-reactive protein return to normal. If the joint puncture culture is negative, re-operation can be considered. The pathology must be confirmed after surgery to confirm that the infection has been controlled. . Resection arthroplasty or arthrodesis can also be considered for infections that are difficult to control. 3. patellofemoral joint complications Including patellofemoral joint instability, humeral fracture, humeral prosthesis fracture or loosening, humeral impact syndrome and knee extension device fracture, etc., often associated with soft tissue imbalance and poor prosthesis position. Therefore, choosing the right prosthesis and mastering the correct surgical operation are the most important methods to prevent patellofemoral joint complications. Among them, the knee extension device is the most serious complication, and the joint function after reconstruction is not too good. 4. Vascular nerve complications Arterial injury after knee arthroplasty is a rare and serious complication. The condition of the affected limb should be checked in detail before surgery. If you find any problems, please consult a specialist. Common peroneal nerve injury is more common, mainly related to the correction of fixed valgus and flexion deformity. Symptoms of common peroneal nerve injury often occur within 24 hours after surgery. Once found, immediately loosen the knee bandage and fixation, bend the knee 15 ° to relax the common peroneal nerve. When the foot is drooping, it should be fixed with a brace. The effect of surgical exploration of the total nerves of the sputum is not certain. 5. Periprosthetic fractures Previously, it was inclined to non-surgical treatment. At present, different surgical methods are preferred depending on the type of prosthesis and the condition of the fracture.