The artificial total hip joint consists of an artificial acetabulum and an artificial femoral head. In the past, both of them were made of metal, and they are not used now because of many complications in practice. At present, both domestic and foreign countries use the acetabulum made of ultra-high polymer polyethylene and the artificial femoral head made of low strength modulus metal. There are more types and designs of artificial total hip joints, mainly the diameter of the femoral head and the design of the acetabular surface with bone fixation. A thicker acetabulum with a relatively small diameter artificial femoral head makes up a total hip with low cephalic socket friction, stable artificial socket, and low local reaction.
I. Indications.
If you are over 50 years old and have the following indications, artificial total hip replacement is feasible, and caution should be exercised for those under 50 years old.
1, the acetabular destruction or obvious degeneration, pain, joint activity is limited, seriously affect life and work.
2, rheumatoid hip arthritis, joint ankylosis, stable lesions, but good knee joint activity.
3.Aseptic necrosis of the femoral head and old femoral neck fracture complicated by femoral head necrosis with severe deformation, collapse and secondary osteoarthritis of the hip joint.
4, artificial femoral head replacement, artificial total hip replacement, hip fusion failure.
Second, contraindications.
1, the elderly and frail, with serious heart and lung disease, can not tolerate surgery.
2, severe diabetic patients.
3, septic arthritis or osteomyelitis of the hip joint.
4.Tuberculosis of the hip joint.
5.Severe damage to the acetabulum or obvious degeneration of the acetabulum.
3. Pre-operative preparation
1.Comprehensive physical examination to understand the heart, lung, liver and kidney functions, and appropriate treatment to adapt to the surgery.
2, the femoral neck fracture should be pre-operative skin traction or tibial tuberosity traction, first correct the distal displacement of the fracture and release the contracture of the muscles around the hip joint, so as to facilitate intraoperative reset and reduce postoperative complications.
3.Routine antibiotics should be given 1~3 days before surgery, and injection in the affected area is prohibited to prevent infection.
4, routine skin preparation; enema the night before surgery; fasting 12 hours before surgery.
5.Select an artificial femoral head of similar size and place it on the same plane of the affected hip to take an X-ray film, according to which a suitable artificial femoral head and a larger or smaller one will be prepared.
6.Prepare special instruments such as medullary file, artificial femoral head hammer, femoral head extractor, femoral head holder, bone cement, etc.
IV. Anesthesia.
Epidural anesthesia.
V. Surgical steps.
1, position: lateral prone position, with the affected limb on top and the affected hip flexed at 45° to facilitate intraoperative activities in all directions. If the anterolateral exposure route is required according to the condition, the patient should lie on his back with the affected hip elevated.
2. Incision: Any route can be fully exposed, and can be chosen according to the patient’s condition and the operator’s habit. If there is hip flexion contracture, it is appropriate to use the anterior incision. The posterior surgical route is simpler and less damaging, so it is mostly used clinically.
3.Excision of the joint capsule: After revealing the joint capsule, the joint capsule is cut in a “T” or “I” shape, turned to both sides, and the joint capsule at the base of the femoral neck is pushed open to fully reveal the head, neck and base of the femur.
4.Probe and remove the femoral head: rotate the affected limb and probe the fracture of the femoral head and neck, the femoral head can be seen rotating in the acetabulum, continue to flex the affected limb and rotate the distal femoral neck to reveal the fractured end of the femoral head in the acetabulum. The femoral head is removed by drilling into the head with a femoral head retriever, pulling the head away from the acetabulum, and cutting the round ligament by reaching between the head and socket with scissors. The diameter of the femoral head is measured and a preoperative radiograph is taken to select a suitable size of artificial femoral head. In case of femoral head necrosis, the femoral head is removed with a wire saw at the predetermined osteotomy line after the hip joint is dislocated by inversion, internal rotation and flexion of 90° [Figure 1 (5)]. Remove all soft tissues in the acetabulum and stop the bleeding by filling with gauze. The affected limb was flexed, internally retracted and internally rotated to expose the femoral head neck and medullary cavity to the surgical field.
5. Revision of the femoral neck: Excise the redundant femoral neck, with the upper end of the incision line starting from the upper edge of the base of the femoral neck. The incision is made inferiorly and ends 1.0-1.5 cm above the lesser trochanter, preserving the femoral spur, and the osteotomy is tilted forward 15°-20° to maintain the anterior inclination of the artificial femoral head after implantation. After osteotomy, the soft tissue around the femoral neck is covered with wet gauze for protection, and a rectangular hole is scraped in the longitudinal axis of the cut surface, which corresponds to the base of the stem of the artificial femoral head. A special medullary file is used to enlarge the medullary cavity to the size of the stem of the prosthesis. Note that the direction of the enlarged medullary cavity should be controlled during the process of enlargement and should not be penetrated through the lateral wall of the femoral stem. Finally, the femoral stalk is inserted for inspection and excess bone is removed to ensure that the prosthesis has practical mechanical placement and bony support.
6, Placement of artificial femoral head: Place the selected femoral head directly in the acetabulum and test for suitability. It should be the same size as the acetabulum, with free movement and a certain negative pressure when the acetabulum is pulled out. Check whether the placement of the prosthesis and the range of movement of the artificial joint are suitable, and if there is any impropriety, it should be remedied before final fixation.
7.Reset the artificial femoral head: tract the limb, push the artificial femoral head with fingers, when it is close to the acetabulum, externally rotate the lower limb to make the head enter the acetabulum. After the reset, the hip joint can be tested in abduction and adduction, paying attention to the mobility and the tendency of dislocation.
8.Install negative pressure drainage: suture the wound to stop bleeding thoroughly, disinfect the wound again with disinfection solution, then flush with saline and suture the joint capsule. A negative pressure suction tube was placed near the artificial femoral head, and a small incision was poked through the nearest skin to drain the tube out of the skin. The wound is closed in layers. Fix the drainage tube, wrap the mouth with sterile gauze, and prepare to connect the negative pressure suction device back to the ward after the operation.
VI. Postoperative treatment.
1, postoperative lifting should be careful to maintain the abduction, internal rotation and extension position. Traction of the affected limb in the abducted neutral position for 1 to 2 weeks to prevent inversion and external rotation to avoid dislocation. Later change to orthopedic shoes in the same position for 2 to 3 weeks.
2.Apply antibiotics after surgery to prevent infection.
3, effective negative pressure suction is extremely important, mainly to prevent infection, but also to observe and record the color change of drainage fluid and drainage flow. The drainage tube should not be left in place for more than 72 hours, and the drainage flow should be removed only after 24 hours of less than 20 ml.
4, postoperative review X-ray film to check the position of the artificial femoral head in the acetabulum, but also to facilitate postoperative follow-up comparison.
5.After surgery, you should move the unfixed joints, do muscle contraction exercises and massage the lower limbs to prevent deep vein embolism. 2-3 days later, you can sit up and gradually increase the active and passive range; 10-14 days after surgery, the stitches are removed; 3-7 days after surgery, you can go down with the assistance of a walker. At least 3 months should be spent walking with the protection of crutches, and the exercise process can be supplemented with physical therapy. Active functional recovery exercises should be carried out at the appropriate time according to the different conditions. In short, moderation is important to pay attention to at all times.
6, strict regular follow-up every 2 to 3 months in order to guide the exercise. X-ray examination should be taken regularly in order to detect complications at an early stage, such as pain and inflammation, the cause should be found and dealt with in a timely manner. X-ray examination should be observed for the presence of bone and bone cement, translucent band between the shank, shank fracture, bone cement fracture, relationship between the shank end and the medial side of the medullary cavity, sinking of the prosthesis, resorption of the femoral spur, cracking of the bone cement on the medial side of the upper femur, bone resorption, etc.
7, if improperly treated after surgery can lead to recurrence of the disease; this is what many patients worry about; thinking that the hospital’s treatment is not in place.
VII. Schematic diagram of the effect.
Before surgery
After surgery