Acetabular revision surgery

There have been many reports on the use of bone cement fixed prosthesis for revision. Callaghan reported that 8.6% of 139 patients undergoing revision surgery were undergoing secondary revision surgery. Among them, 64 cases of acetabular and shank were repaired. The average follow-up was 8 years and 9 years. The patients were all elderly and 76% were female. The total secondary revision rate was 6.7%. The acetabular cup loosening rate was 67%. 5%. In this type of case, X-ray films showed 3% acetabular displacement, and 11.7% had bone-bone cement transparent area. There was no long-term follow-up report of cementless acetabular fixation. Harris reported that 60 cases of acetabular cup revision replacement with a semi-spherical porous surface were screwed and followed up for 12 to 36 months without any loosening or displacement. Hedley reported a 6.6% acetabular cup displacement with a PCA prosthesis. Engh reported that in 4.4 years of follow-up, the loosening rate of the spiral cup was 9.6%, and only 2 of the 54 cases of porous surface screw fixation were loose. Amstutz reported that 14 cases of screw cups were followed for 30 months, and 11 cases of acetabular movement occurred. It shows that the semi-circular acetabular screw fixation effect is better than the spiral acetabular cup, and the secondary revision rate is low. Treatment of diseases: acetabular fractures Indication In patients with failed acetabular prostheses, after removal of bone cement and granulation fiber tissue, the acetabular bed often becomes an enlarged acetabulum with few cancellous bones and more bone defects and peripheral bone sclerosis. If the bone cement is applied again, the fixation effect is poor, the loosening rate is high, and the second damage is easily caused to the bone bed. Therefore, it is advisable to rebuild the acetabular cup with a cement-free hemispherical metal for most cases. Because the cement fixed acetabulum has the advantages of short operation time, less bleeding, and early waking after surgery, bone cement can still be used to fix the acetabular cup for elderly patients over 70 years old with less acetabular cartilage defects. Preoperative preparation 1. Comprehensive consideration of the general condition, including age, weight, health, activity, etc. is suitable for surgery. 2. Physical examination should pay attention to the length difference between the two lower limbs, the soft tissue contracture of the joints, which can affect the postoperative dislocation and whether it can walk. 3. X-ray examination of the fixation of the prosthesis, estimation of the size of the prosthesis and whether bone grafting is required. The American College of Orthopaedic Surgeons (AAOS) classifies acetabular defects into five types: type I is the acetabular edge bone defect; type II is the central or peripheral bone defect of the acetabular fossa; type III is the acetabular rim and acetabular fossa. Defect; the continuity of the type IV pelvis is destroyed, and large bone grafting is required. This type is rare; the V type cannot be repaired and hip fixation is required. The choice of acetabular cup fixation method: excessive acetabular bone defects, bone cement fixation during revision surgery, high postoperative failure rate. For II, III, IV and some type I acetabular defects, the boneless acetabular cup should be replaced after bone grafting. Of course, we need to consider other situations of the patient. If the patient is old and frail, the life expectancy is not long and can still be fixed with bone cement. Factors such as short operation time, less bleeding, and firm fixation during surgery are beneficial to the patient. Surgical procedure 1. During the revision surgery, due to the formation of thick scar tissue around the joint and adhesion fixation, it is difficult to dislocate the joint. It should be noted that the joint capsule is removed along with the scar. If the approach is difficult to expose, you should not hesitate to use a large trochanter. This is more convenient to expose and less bleeding. 2. The principle of removing the acetabular cup and bone cement is to remove the bone cement and granulation tissue without damaging the bone. It is not difficult to remove the loose acetabular cup. If the acetabulum is fixed firmly, use a thin acetabular chisel to cut between the bone cement and the acetabular cup, taking care not to hurt the edge of the acetabular bone. After the acetabular cup is slightly separated from the cement bed, the acetabular cup is smashed from the cement bed by the intrusion on the upper edge of the acetabular cup. Sometimes the acetabular cup is difficult to remove, and the acetabular cup V-shaped portion can be cut off with a chainsaw or a bone chisel to remove it. 3. Cementless acetabular prosthesis revision, the application of hemispherical metal to strengthen the acetabulum, the main points of the revision surgery is: 1 the greater the contact area between the metal reinforcement cup and the acetabular bone, the more secure the fixation. For larger acetabular bone defects, autologous cancellous bone grafting should be performed. If the bone mass is insufficient, the focus is on the upper and posterior walls of the acetabular bone. All other parts can be bone grafted with allogeneic bone. The acetabular edge bone graft is screwed. The porous surface of the metal reinforcement cup should be coated with bone cement to ensure bone growth. 2 Metal-reinforced acetabular cups should be firmly fixed with screws. Due to the poor bone quality of the acetabular bone and even the bone defect, the screw must be fixed at a better bone and cannot be fixed at the bone graft. complication 1. Incision infection and treatment Infection after artificial hip arthroplasty is a serious complication and one of the main causes of hip joint failure. The incidence is generally about 3% to 5%, and even as high as 10% or more, of which early infection accounts for 1.6% to 3.0%, and late infection accounts for 2.2% to 5.2%, which is much higher than that of general hip surgery. The clinical manifestations of early infection are the same as general purulent infections. The signs of acute inflammation are obvious. Postoperative body temperature continues to increase, suffering from hip pain, pain during passive activities, swelling of soft tissue around the hip joint, skin edema, high local skin temperature, and white blood cells. The total number and neutrophils were high, especially the ESR increased significantly. Late deep infection, clinical manifestations are more special, generally local acute inflammatory response is not obvious, body temperature and white blood cells are often not too high, but erythrocyte sedimentation rate is fast, generally as high as 40 ~ 50mm / h, or even up to 100mm / h, so some people put Increased erythrocyte sedimentation rate is the basis for postoperative infection or potential infection of artificial hip joints. In addition, the C-reactive protein content of patients with advanced infection is also significantly increased. Prevention of postoperative infection is the key to successful hip arthroplasty. The key points are to prevent the following factors: 1 patient's aseptic preparation; 2 strict maintenance of the sterility of the operating room; 3 gentle operation, reduce trauma , try to shorten the operation time, suture the incision and repeatedly wash the wound thoroughly; 4 put a negative pressure drainage tube inside the wound; 5 postoperative systemic use of antibiotics. Once an artificial hip joint is found, infection should be actively treated. Early superficial infections should be drained early and use effective antibiotics. Early deep infections should be taken out of the artificial prosthesis in time, the lesions should be completely removed, the wounds washed, and 0.5 g of gentamicin powder can be added to 40 g of bone cement to fix the prosthesis, re-implant the prosthesis, and in the wound. Put isoform GFDA6 oxacillin 1g or cephalosporin 1g into the wound, place one perfusion tube and one drainage tube in the wound, and then suture the incision. After the systemic use of antibiotics, effective antibiotics can be continuously applied for 6 months. 2. Artificial hip joint loosening Prosthesis loosening is also one of the important reasons for the failure of artificial hip replacement. Generally, the femoral prosthesis loosening rate was 19.5% 2 to 5 years after surgery, and it was 44.3% in 6 to 9 years. Looseness is closely related to the shape of the prosthesis, bone and fixation techniques. Looseness often occurs more than 2 years after surgery. The longer the postoperative time, the higher the loosening rate. The clinical manifestations are mainly pain, and progressively aggravated. When the artificial acetabular cap is loose, the pain often radiates to the buttocks. When the artificial femoral head is loose, it is painful in the hip, groin, thigh or knee. The pain in the middle of the rotating thigh is aggravated, sometimes There is a sound in the deep part of the hip joint activity, and there is a phenomenon of "interlocking". On the X-ray film, when the artificial acetabular cap is loose, it shows that there is a boundary between the skull cap and the interface, and the prosthesis is displaced. When the artificial femoral head is loose, the femoral neck is absorbed, and the absorption of the artificial femoral head is absorbed and translucent. Area. Arthrography shows that the contrast agent enters between the bone and the cement or prosthesis. Artificial hip revision surgery should be performed after the diagnosis of loosening. 3. Artificial hip dislocation The incidence of dislocation after artificial hip replacement was 0.2% to 6.2%. Most of them occur within 1 month after surgery, which is called early dislocation. It is feasible to close the treatment and the hip "human" plaster can be fixed for 3 to 4 weeks. For some patients with difficult or late dislocation (occurring 1 month after surgery), a reduction should be performed to correct the cause of dislocation.