Some of the complications of artificial total hip arthroplasty are specific to the procedure, while others occur after major surgery in any elderly person. Nerve palsy, swelling of the joint with blood accumulation, deep vein thrombosis, and pulmonary thromboembolism occur early after surgery. Prosthesis loosening, prosthesis fracture, and osteolysis are late complications that usually occur years after successful initial surgery. Infections, dislocations, and fractures around the prosthesis can occur either early or late in the postoperative period, as well as at other times, depending on the situation. Nerve Injuries Nerve injuries to the sciatic, femoral, and peroneal nerves can occur as a result of direct trauma from instruments during surgery, or traction on the lower extremity, or compression from soft tissue retraction instruments, repositioning of the operated limb, and lengthening of the limb after surgery, as well as injuries caused by thermal cauterization of or compression on bone cement. According to reports, the incidence of nerve injury in first-time hip replacement is approximately 0.7% to 3.5%.Amstutz reported that the rate of nerve injury in revision surgery increases to 7.5%.1 The sciatic nerve and peroneal nerve are the most common causes of nerve injury in hip replacement. 1. Management of sciatic and common peroneal nerve injuries Patients with sciatic and common peroneal nerve injuries should be immobilized with the ankle in a dorsiflexed position to prevent the development of a fixed horseshoe foot deformity. Although complete neurologic recovery is uncommon, most patients recover some function. Surviving motor function with partial recovery during hospitalization indicates a good prognosis and rarely requires sciatic nerve examination. Exploratory nerve surgery may be considered if there is no recovery after 6 weeks or if there is a suspicion of compression of the sciatic nerve by cement or screws passing through the acetabulum. A CT scan of the acetabulum can help to show the location of the nerve injury that caused it. 2. Management of femoral nerve injury Femoral nerve injury is relatively rare and can be easily overlooked in the early postoperative period. The femoral nerve is located in front of the joint capsule, separated from it only by the iliopsoas muscle and tendon. It can be injured by a retractor placed anterior to the iliopsoas muscle, or during resection of the anterior joint capsule of the anterior hip joint or when retracting the femur to file the acetabulum. In addition, a pulling palsy of the femoral nerve may occur after correction of a severe hip flexion contracture. The prognosis for recovery from femoral nerve injury is relatively good compared to the sciatic nerve. However, in the event that the femoral nerve is embedded and compressed in a protruding bone cement, then it has a poor prognosis. If the quadriceps muscle is weak, a knee brace can be worn to protect the knee and prevent knee weakness and falls while walking. Deep vein thrombosis and pulmonary embolism (I) Clinical manifestations Artificial total hip replacement can cause venous injury, slow venous blood flow and hypercoagulable state of blood, which makes the patient prone to thrombosis, and will lead to a high incidence of deep vein thrombosis if effective preventive measures are not taken. In 1997, Prof. Lu Houshan and others first reported that the incidence of DVT in the non-preventive group after total hip arthroplasty was about 40%, and the incidence of proximal deep vein thrombosis was 17%. Yu Nansheng et al. reported that after anticoagulation prophylaxis after hip arthroplasty from 2001 to 2005, the incidence of thrombosis could still reach 20.6%. Fifty to eighty percent of patients with deep vein thrombosis may have no clinical symptoms and clinical manifestations, but it causes great harm because it can be complicated by fatal pulmonary embolism and long-term lower extremity deep vein insufficiency. Timely detection and treatment depend on early detection and proper diagnosis of the disease state. Deep vein thrombosis usually starts sharply, with swelling, hardness and pain in the affected limb, which is aggravated by activity, pressure pain at the site of thrombus, striae can be detected along the blood vessels, the distal limb or the whole limb of the thrombus is swollen, the skin shows a blue-purple color, the skin temperature is lowered, and the dorsalis pedis and posterior tibial arterial pulsations are weakened or disappeared, and even venous gangrene may appear. When the thrombus extends to the inferior vena cava, obvious edema may appear in both lower limbs, buttocks, lower abdomen and external genitalia. (When the thrombus occurs in the muscular venous plexus of the lower leg, Homan’s sign (straight leg and ankle extension test) and Neuhof’s sign (compression of the gastrocnemius muscle test) are positive. Ancillary tests for DVT include compression ultrasonography, color Doppler ultrasound, radionuclide angiography, phlebography with spiral CT, fluoroscopy with phlebography, and detection of D-dimer in the blood. Venography is the “gold standard” for diagnosis, but it is invasive and expensive. Spiral CT venography is a new diagnostic method that has been developed in recent years, which can simultaneously examine the deep veins of the abdomen, pelvis and lower extremities. DVT dislodgment passes through the right atrial chamber and leads to embolization of the corresponding diameter of the pulmonary artery branches. Pulmonary embolism may occur with or without symptoms, and in a few cases may progress to fatal pulmonary embolism. Pleurisy-like chest pain is the most common symptom of pulmonary embolism, often sudden onset, and rapid progressive respiratory function, because of the obstruction of pulmonary artery branches, the lungs are not enough blood supply, resulting in ventilation and blood supply ratio imbalance, and seriously lead to the patient’s fainting, or even shock. Chest radiographs commonly show uneven distribution of texture in both lungs, bulging of the pulmonary artery segments, pulmonary infarcts, atrial enlargement on the right side, and pleural exudates, but these are not specific for pulmonary embolism. Blood gas analysis often shows hypoxemia, and the electrocardiogram may show right ventricular overload, i.e., inverted Q waves in all three leads. Radionuclide lung scanning demonstrates abnormal ventilation and blood flow ratios in the lungs. Spiral CT pulmonary arteriography has a very high sensitivity and specificity of 95% and has recently become the first-line clinical screening method for acute pulmonary embolism. There are also pulmonary angiography, echocardiography, and plasma D-dimer assay. (C) Routine preventive measures 1, the basic measures of deep vein thrombosis and pulmonary embolism include avoiding venous injury during the operation, encouraging patients to start the active activities of the feet and toes as soon as possible after the operation, and doing more deep breathing and coughing maneuvers to improve the ventilation of the lungs, and leaving the bed as early as possible. 2.Mechanical preventive measures include: plantar vein pump, intermittent inflation compression device and step-by-step compression stockings. In clinical trials, the efficacy of antitethering drugs is better than that of nonpharmacologic prophylaxis, so nonpharmacologic prophylaxis alone is not recommended. 3, drug prophylaxis treatment measures are currently commonly used in clinical practice there are three methods: (1) 12 hours before surgery or 12 to 24 hours after surgery (2 to 4 hours after the epidural catheter is removed) began to carry out subcutaneous injection of conventional dose of low molecular heparin, or 4 to 6 hours after surgery began to give the conventional dose of half of the next day to increase to the conventional dose. (2) Pentosan sodium 2.5 mg, starting 6 to 8 hours after surgery. (3)Vitamin K antagonist, such as warfarin, bicoumarin type of anticoagulant, should be applied before or on the night after surgery, the dosage needs to be done to monitor and maintain the international standardized ratio of prothrombinogen time at 2.0 to 2.5, do not exceed 3.0.The duration of any of the above anticoagulant methods is generally not less than 7 to 10 days, and the combination of medication is not recommended. Once a patient develops DVT after surgery, the relevant departments should be consulted immediately, and therapeutic doses of anticoagulants should be given in a timely manner, and care should be taken to prevent PTE from occurring due to thrombus dislodgement Infections (I) Etiology Postoperative infections in prosthetic arthroplasties are usually catastrophic. Part of the reason for the higher rate of infection in patients with metal implants and the difficulty in eradicating it may be caused by the growth of bacteria in the biofilm on the surface of the biomaterial. This biofilm is anchored to the metal surface, blocking the body’s defense system and antibiotics, which do not readily kill these bacteria, so that sometimes the prosthesis needs to be removed in cases of severe infections, in order to remove the infected foci completely. (ii) Prevention Strict surgical operation and the environment of the operating room are essential to prevent infection. Waterproof surgical gowns and therapeutic towels are recommended for sheet preparation, and double layers of gloves are recommended. Gentle clamping of tissue during surgery to minimize dead space and reduce hematoma formation is particularly important. Airborne bacterial handling is further minimized by limiting walking through the operating room, applying laminar flow booths, and having the surgeon wear a closed, vented gown. Another important factor in reducing perioperative infections is the routine preoperative prophylactic application of antibiotics. Generally, a second-generation cephalosporin antibiotic such as cefuroxime should be given half an hour before the skin is cut and incised. The majority of post-prosthetic arthroplasty infections are caused by gram-positive cocci, particularly Staphylococcus aureus and Staphylococcus epidermidis, and although the incidence of infections caused by these bacteria has remained more or less stable, they are increasingly virulent. Resistance to methicillin has become very common in many medical centers. The ability of staphylococci to synthesize polyglycoprotein complexes is now considered a marker of high virulence. The overall incidence of infection is not high, however, so routine prophylactic application of antibiotics other than cephalosporins and semisynthetic penicillins does not seem to qualify. Gram-negative infections are commonly associated with hematogenous infections, especially those originating in the urinary tract. Mixed infections are usually seen as multiple infections following sinus tract opening. Unexplained chills, high fever (more than 38.5 degrees for three consecutive days), localized redness, swelling, pain, and tenderness of the wound, and increased local skin temperature in the early postoperative period should be highly considered to alert to the possibility of postoperative infection. (C) Treatment Principles of treatment after early postoperative infection: take specimens for bacterial culture and antibiotic sensitivity test to guide the adjustment of antibiotic application; if the infection is only superficial, avoid joint puncture to avoid contamination of the deep joints, and should be carried out as early as possible in the operating room under strict aseptic conditions, layer by layer to explore and clean up infected and necrotic tissues; if the infection is really superficial, use a large number of saline containing antibiotics to flush thoroughly. If the infection is indeed superficial, the wound can be thoroughly flushed with a large amount of saline containing antibiotics, a negative pressure drainage device can be placed, and the wound can be loosely sutured intermittently. If the infection has spread to the joint cavity, the wound should be thoroughly irrigated with antibiotic-containing saline, all necrotic, granulation tissue should be removed, and the joint must be dislocated to allow for more thorough debridement, its liner should be removed to remove granulation tissue from the interface, and even, in some cases, the polyethylene liner of the acetabulum should be replaced, as well as the artificial head of the femur on the femoral stem, whether it be ceramic or metal. The stability of the prosthesis should be carefully tested, and only prostheses that do not show signs of loosening should be allowed to remain in situ, with repeated fluid tissue sampling for culture and pathology. Antibiotic beads may be placed in the wound to maintain a high local concentration of antibiotics. However, antibiotic chain beads should not be left in the wound for more than 2 weeks or they will be difficult to remove because of fibrous tissue growth. In addition, the appropriate antibiotic is determined based on bacterial cultures and drug sensitivity tests. Intravenous medication is administered for 4 to 6 weeks, depending on wound healing. Thereafter, the antibiotic can be changed to an oral one if still clinically indicated. Vigilance must be exercised regarding prognostic progression of the disease because even if the infection is recognized early and appropriate therapy is started immediately, the causative organism is sensitive to the antibiotic of choice and the infection is still often difficult to control and clear completely. At that time, drainage of the joint and removal of the prosthesis and bone cement will be inevitable.