Indications for primary total hip arthroplasty
1.Primary osteoarthritis of the hip joint.
2, Ischemic necrosis of the femoral head.
3.Hip dysplasia or congenital hip dislocation secondary to osteoarthritis.
4, rheumatoid arthritis.
5.Femoral neck fracture in the elderly: ① femoral neck fracture with displacement; ② old fracture of the femoral neck does not heal or ischemic necrosis of the femoral head.
6, elderly inter-rotor fracture: ① the hip joint had lesions before the inter-rotor fracture, such as osteoarthritis, rheumatoid arthritis or ischemic necrosis of the femoral head; ② the old fracture of the inter-rotor does not heal.
7, secondary osteoarthritis after hip trauma.
8, ankylosing spondylitis hip joint involvement.
9, hip joint infection, residual joint dysfunction after surgery.
10, other special diseases, such as systemic lupus erythematosus, psoriatic arthritis, hip tumor, etc.
Contraindications to primary total artificial hip arthroplasty
① Active infection foci in the patient;
②Neurological joint disease;
③Loss of hip abduction muscle strength or less than grade 4;
④Any other systemic disease or weakness that cannot tolerate the surgery.
Pre-operative preparation
1. Detailed medical history of the patient, including existing and past medical history and drug allergy history.
2. Combination of general and specialized examination. The general examination focuses on the integrity of the skin and mucous membrane, inflammation of the oral cavity and gums, abnormalities of the heart and lungs, and abnormalities of the nervous system. Specialized physical examination focuses on checking the hip for scar and sinus tract, hip joint range of motion, limb length, lower limb sensory muscle strength, especially abductor muscle strength.
3.Score the function of the hip joint, with Harris score being the most commonly used method.
4, laboratory tests: blood tests ① three routine, ② liver and kidney function, electrolytes, ③ blood sedimentation, ④ C-reactive protein, ⑤ blood type, ⑥ coagulation function, ⑧ full set of pre-transfusion screening.
Imaging ① chest X-ray (frontal and lateral films), ② pelvic plain films, frontal and oblique films of the affected hip (including the upper 2/3 of the femur); the photographs should be enlarged by 100% to indicate “for measurement”.
Electrocardiogram and abdominal ultrasound (liver, bile, pancreas, spleen, both kidneys, etc.).
5.If the patient is found to have a history of heart disease, an ambulatory electrocardiogram should be arranged, and an echocardiogram should be added for those with arrhythmia; for patients with a clear history of coronary artery disease, a coronary CT examination or coronary angiography should be arranged; for patients with a history of lung disease such as chronic bronchitis and those aged >70 years, a pulmonary function examination should be arranged; for patients who are bedridden for a long time, a deep vein ultrasound of both lower limbs should be performed.
6.Any abnormalities found by medical history, physical examination and laboratory tests should be actively dealt with to adjust the whole body condition to the best condition before surgery.
【Template measurement and prosthesis selection
The purpose of template measurement is ① to detect anatomical variants, ② to select suitable acetabular and femoral prosthesis, ③ to measure the difference in length of both lower limbs, ④ to determine the center of rotation of the artificial joint and the osteotomy site of the femur.
The acetabular template measurement should ① determine whether the bone can be well fixed by non-cemented fixation or cemented acetabular cup fixation, ② determine the placement position and size of the acetabulum, and ③ determine the rotation center of the new hip joint.
The femoral template measurement should ① determine whether the femoral bone quality is suitable for non-cemented fixation or cemented fixation, ② determine the osteotomy plane of the femoral moment, and ③ adjust the off-center distance of the femur and the length of the neck.
Regarding the choice of prosthesis, it is now internationally accepted that the long-term survival rate of non-cemented prosthesis on the acetabular side is higher than that of cemented prosthesis, so non-cemented prosthesis on the acetabular side should be used as much as possible. Long-term survival has been reported for both non-cemented and cemented prostheses on the femoral side, but non-cemented fixation is preferred for younger patients with good bone condition. In elderly patients with severe osteoporosis and a “chimney-shaped” femoral medullary cavity, cemented prostheses are preferred.
Surgical Approach
There are many surgical approaches that can be used for primary total hip arthroplasty, commonly used are the anterior approach, the lateral approach and the posterior-lateral approach.
The anterior approach was first described by Smith-Peterson, so it is also called the Smith-Petersen approach. This approach is mainly through the muscle space and does not need to cut the muscle, so it has certain advantages for maintaining the continuity and tension of the muscle and speeding up the postoperative recovery process.
The lateral approach was first designed by Watson-Jones-McFarland and Osborne in 1935 and has since been refined by Bauer and Harding. The advantages of the posterolateral approach are that the rate of postoperative dislocation is very low, but the disadvantages are (1) the need to perform a greater trochanteric osteotomy during surgery and poor exposure of the acetabular side, and (2) the ease of damaging the superior gluteal nerve by splitting the abductor muscle over 125px.
The posterior lateral approach, first described by Kocher and Langenbeck, provides satisfactory surgical exposure in most cases and has the advantages of short exposure time, minimal muscle damage, and rapid postoperative recovery. The posterolateral approach is highly extensible and can be easily extended proximally and distally when needed to fully visualize the surgical field. The more commonly used approach is the postero-lateral approach, which is described here.
Under general anesthesia or combined lumbar and rigid anesthesia, the patient is placed in a lateral position with the affected limb on top, the anterior and posterior baffles are fixed to the torso, the perineum is closed with film, the wound and surrounding skin are brushed and dried with antiseptic solution, and the wound is routinely disinfected, toweled and sterile film is applied.
2. Make a slightly curved incision centered on the greater trochanter, about 13 cm long, with the proximal end at an angle of 30-40° backward to the anatomical axis of the femur, about 5 cm long, and the distal end in a mild arc along the anatomical axis of the femur, about 8 cm long. The subcutaneous tissue and broad fascia were incised, the gluteus maximus fibers were bluntly separated in the direction of the incision, the affected hip was mildly flexed and internally rotated, the gluteus maximus femoris stop was partially severed, and the pull hook was retracted posteriorly to expose the posterior part of the upper femur and the small trochanter, etc.
3. Immediately posterior to the femur, cut the stop of the external rotator muscle group, cut the posterior joint capsule, and release the hip after further flexion, internal retraction and internal rotation of the affected hip to dislodge the femoral head. The femoral neck is truncated 0.5~1 cm above the lesser trochanter and the femoral head is removed to complete the initial reveal.
Principles of acetabular side prosthesis placement
1. Acetabular exposure: return the affected hip to the initial position, pull the femoral neck off with bone hooks, place acetabular pulling hooks on the anterior lower and posterior lower walls of the acetabulum, place vertebral plate pulling hooks on the posterior upper wall, pull the gluteus medius muscle with skin pulling hooks on the anterior top, and remove the bone hooks. The synovial membrane and glenoid lip were excised with an electric knife around the acetabular rim, and the transverse acetabular ligament was partially excised. Fully expose the acetabulum
2, Acetabular grinding and filing: Generally, women start with 44mm and men start with 46mm acetabular file, gradually increase the type of acetabular file, grind off the cartilage in the socket until the subchondral bone evenly bleeds, pay attention to the depth of the acetabular file and the angle of forward abduction during the grinding and filing process.
3, acetabular prosthesis implantation: place the acetabular prosthesis trial mold corresponding to the final acetabular file model, check the inclusive and acetabular angle position. Remove the trial mold and place a non-cemented acetabular prosthesis that is 1-2 mm larger than the final acetabular file model, maintaining a forward tilt of 200 and an abduction of 450, and hammering evenly until the central hole of the prosthesis fits closely to the bottom of the acetabulum. If the inclusion is slightly poor or the patient is osteoporotic, 2~3 screws can be used to assist in fixation. The direction of screw implantation should preferably be above the posterior acetabulum to avoid damage to the pelvic vessels and nerves. Load the lined trial mold.
[Femoral side prosthesis placement principles
1. Femoral exposure: The affected hip is placed in flexion at 600 and internal rotation at 900 degrees, and the knee joint is flexed at 90° in order to
Determine the femoral anteversion angle. The pointed sled femoral exposure hook is placed under the cortex in front of the broken end of the femoral neck, and another narrow shank hoffman pull hook is placed in the small rotor to reveal the truncated broken end of the femoral neck.
2, trimming the medullary cavity: the groover is placed close to the medial aspect of the greater trochanter to groove the proximal femur, maintaining an anterior inclination of 150, and the medullary probe is inserted into the medullary cavity in a prograde direction. Use a medullary file from No. 8 to large to enter the medullary cavity, or choose a medullary file 2 sizes smaller than the intended femoral stem prosthesis, to the edge of the medullary file in the groove and a little cortical bone is appropriate, mark the depth of the medullary file.
3, test reset: the last type of medullary file do not take out, only remove the handle, place the femoral head test mold, assistant – hand bending knee traction, external rotation, abduction of the affected limb, the other hand index and middle fingers to hold the neck of the test mold to assist traction, test reset the joint. Check the joint mobility and joint stability, the length of the affected limb and the contralateral limb. If necessary, femoral heads with different neck lengths were used to adjust the length of the affected limb. Require hip flexion > 900, internal rotation 300, hyperextension 100, external rotation 150, abduction 450 Good posterior stability, no dislocation, no obstruction to the activities of all sides of the joint.
4.Installation of liner: after satisfactory trial reset, the acetabular liner can be installed. Before hammering the liner, make sure that there is no soft tissue embedded in the perimeter of the acetabular prosthesis. The polyethylene liner has a high side design to prevent dislocation, and the high side position can be adjusted according to the intraoperative stability. Before installation of ceramic and metal liners, rinse and dry the conical surface of the inner wall of the acetabulum to ensure that there is no tissue/particle entrapment, then implant the liner parallel to the cup along the metal cup with your fingers (make sure the edges are equal), touch your fingers along the edge of the liner in a circle to check the accurate position of the liner implantation, and then gently tap it with a plastic hammer.
5.Femoral prosthesis implantation: Select a non-cemented prosthetic stem that matches the final medullary file type, insert it into the medullary cavity, and tap evenly and forcefully until the femoral stem sinks to the pre-marked place. Rinse and dry the stem cone to ensure that there is no tissue/particle entrapment, gently rotate the ball over the stem cone and apply axial pressure, and tap gently with a plastic hammer. The joint is reset and finally checked for mobility.
6. Close the wound: After repeatedly flushing the wound, place a plasma drainage tube in the joint and drain it from the front of the hip. Repair the gluteus maximus stop and the external rotator stop, and close the broad fascia. The subcutaneous tissue and skin were sutured, and the ladder pillow was fixed between the legs.
【Postoperative treatment】.
1. Monitor the postoperative period for 24 hours, record the in and out volume, apply intermittent ice to the surgical incision, and remove the plasma drainage tube and urinary catheter within 24 hours;
2.Apply non-steroidal anti-inflammatory analgesics after surgery, and give Dulcolax to those with severe pain;
3. Instruct patients to sit and stand early, cough and breathe deeply to prevent lung infection;
4.Postoperative application of anti-thrombotic drugs;
5.Apply prophylactic antibiotics for 24 hours after surgery;
6.Review the X-ray film to understand the position of the prosthesis
Functional exercise.
1.Start ankle dorsiflexion, plantarflexion and knee extension exercises after awakening from anesthesia;
2. Start hip flexion, knee extension and hip abduction training on the first day after surgery, and patients under 60 years old can walk on the ground with a walker;
3, the second day after surgery ~ discharge, strengthen the above functional exercises, elderly patients gradually walk on the ground when their physical strength allows, requiring active hip flexion > 90°, extension 0°, abduction 45° at the time of discharge, able to hold a double crutch and walk freely > 10 minutes.
4.No hip joint inversion, no squatting, no stretched legs, no cross-legged movements. Lateral lying with a ladder-shaped pillow between the legs.