Total hip femoral prosthesis revision

Femoral prosthesis loosening, sinking, and prosthetic stem fracture are two major reasons for total hip femoral prosthesis revision. Unlike acetabular prosthesis revision, the use of cement fixation in total hip femoral prosthesis revision is currently controversial. In a report on the use of bone cement for revision surgery, Callaghan reported that 83 of 139 total hip revisions were femoral prosthesis revisions, with a revision rate of 4.3% (prosthesis loosening) and 2.2% (prosthesis stem fracture). . Kavanagh reported 135 cases of femoral prosthesis revision, with a refurbishment rate of 6.4%. In the literature, the rate of revision of the total hip femoral prosthesis was significantly different (2% to 21%). Stromberg reported that after 67 total hip revisions, 16% required revision surgery, 70% of which were due to improper bone cement techniques. Harris used modern bone cement technology (medullary cavity plug, pressure injection of annular bone cement, thickness > 2mm), revision treatment of 43 cases of total hip, the average follow-up of 74 months (60 ~ 110 months), the rate of revision is only 2 %. Bone cement application technology is the key to total hip revision surgery. There is no long-term efficacy report on the revision of cementless femoral prosthesis. Engh reported 127 cases of revision surgery with a porous surface femoral prosthesis, with an average follow-up of 52 months, with a revision rate of 1.5%. Gustilo et al reported 57 cases of femoral prosthesis revision with proximal femoral medullary bone graft, with an average follow-up of 32 months, and a revision rate of 7% due to hypophyseal subsidence. Harris and Galante reported 60 cases of total hip revision surgery, followed by 13 to 36 months, only 1 case of sinking, no reoperation. Cementless total hip femoral prosthesis revision often requires bone grafting for reconstruction of the upper end of the femur. It is reasonable to restore the structure of the upper end of the femur. However, with cement fixation, the medullary cavity may be caused by adverse cement reaction. Further damage. Ucla reported the results of multiple revisions of 40 cases of hip cement. After 38 months of follow-up, 46% had clinical and X-ray failure. Femoral prosthesis loosening can be divided into 4 types: Type I: The interface is flipped, but the bone loss in the medullary cavity is less, and the proximal cortical thinning is less than 50% of its thickness. Type II: The interface is loose, the proximal medullary cavity is enlarged, the thickness of the cortical bone is lost more than 50%, and the bone around the femur is intact. Type III: posterior and medial bone defects of the proximal femur, massive osteolysis in the medullary cavity, and significant displacement of the prosthesis. Type IV: a large bone defect at the proximal end of the femur, and a defect in the bone around the prosthesis. Treatment of diseases: dislocation of the hip Indication Total hip femoral prosthesis revision is suitable for: 1. Boneless artificial total hip revision is suitable for 1 hip joint bone defect less or more extensive; 2 no osteoporosis; patients under 360 years old, it is estimated that the prosthesis is not fixed with bone cement to maintain life. The selected femoral prosthesis stem should be wider and longer to prevent rotation of the prosthesis. Can be applied to type II~IV. 2. Bone cement total hip revision is suitable for 1 patients with good bone bed conditions, bone defects are not much; 2 combined with osteoporosis; 3 older, especially those over 60 years old. The patient can relieve hip pain and move to the ground during his lifetime. Applicable to I to II type. Preoperative preparation 1. Take a full-length X-ray film of the femoral prosthesis and compare it with the contralateral side to estimate the amount of bone loss around the prosthesis. 2. Prepare a prosthesis of sufficient length and width in accordance with bone loss and customize the femoral prosthesis if necessary. 3. Prepare the site from the body bone, or make appropriate allogeneic bones, including cancellous or cortical bone. 4. For cases of type III and IV loosening, wire should be prepared to fix the bone graft. Surgical procedure 1. Removal of femoral prosthesis Because the common femoral prosthesis is a curved handle, such as the direct removal of the femoral prosthesis may cause the cleft palate of the femoral metaphysis. Therefore, the bone cement of the proximal trochanteric region of the femoral prosthesis is removed by using an osteotome or a rongeur, and then the femoral prosthesis is removed. If the prosthesis stem is broken, a 1.5cm long bone window is to be opened at the lateral cortex of the femoral shaft at the fracture handle. The bone cement is removed by electric drill, and the broken handle is displayed. The shank is broken with a pointed humerus. Pull out. 2. Remove bone cement After the bone cement is smashed with a long shank cement chisel, remove it with a long shank. Some bone cement and medullary trabecular bone inlay are very tight, and the surrounding cortical bone is very thin, and it is easy to fracture when it is slightly inadvertent. The bone cement and bone are cut into the interface with a thin bone cement, and the forceps are used to remove it. . The bone cement in the medullary cavity must be completely removed. Use a curette to completely scrape the fibrous membrane or granulation tissue between the bone cement and the bone, and thoroughly flush the medullary cavity. 3. Cement fixed prosthesis The technical requirements for cement fixation are the same as for primary artificial hip replacement. However, the following points should be noted: 1 The prosthesis handle should be at least 2 cm longer than the medullary cavity loss zone; 2 because the medullary cavity is enlarged, it is best to apply the bone cement plug to the distal end of the medullary cavity; 3 when injecting the bone cement, Keep the medullary cavity dry, fully stop bleeding, fill the medullary cavity with gauze after pulse washing, and use a small amount of bone wax to stop bleeding if necessary; 4 If bone grafting is needed due to bone defect, the bone graft should be filled in place before reconciling the bone cement; Prepare a sufficient amount of bone cement, often need to reconcile 2 bags of bone cement, it is best to use bone cement retrograde injection to ensure a firm fixation; 6 due to bone defects in the upper end of the femur often change the upper end of the femur bone markers, special care should be taken when placing the prosthesis For a anteversion angle of 10° to 15°, the cervical collar of the prosthesis should be attached to the bone. The bone cement should not be used to support the cervical collar of the prosthesis. 4. Method for fixing boneless cement femoral prosthesis Reconstruction of the femoral prosthesis must be done in two ways: on the one hand, the new artificial prosthesis is replaced, so that it is firmly fixed, and on the other hand, the femoral anatomy is reconstructed to achieve normal or near normal. The basic method of femoral prosthesis revision surgery is to use a compression fit and an endosphate prosthesis for revision. The femoral prosthesis stem should be inserted into the medullary cavity with sufficient length to maintain axial and rotational stability. The shape of the replaced new prosthesis is preferably similar to that of the original application prosthesis, which reduces damage to more bone and facilitates stress transmission. To maintain the stability of the bone prosthesis, the key is that the prosthesis should be tightly fitted with the autologous cortical bone marrow cavity. For example, the bone graft is easily absorbed by the femoral prosthesis. Under the premise that the implanted prosthesis is tightly fitted and fixed, the bone defect space around the prosthesis needs to be filled with bone graft to restore the physiological shape of the upper end of the femur. The specific method is: 1 Select a suitable prosthesis, the length and thickness of the handle should be embedded in the undamaged marrow cavity. Try to insert the medullary cavity to see if it is appropriate and how much bone defect around it. 2 Take the autogenous iliac bone strip and bone mud. If the bone mass is insufficient, take the freeze-dried bone strip for use. The bone cement is pressed into the pores of the porous surface on the porous surface of the prosthesis. According to the number of bone defects, the autogenous bone strip and the same kind of bone strip are arranged longitudinally around the proximal section of the femoral prosthesis, and the bone strip is tied to the prosthesis stem with a silk thread. 3 Insert the prosthesis into the medullary cavity of the femur, fill the bone graft into the medullary cavity, gently plunge into the bone graft, and enter the medullary cavity to fill the bone defect area. The distal shank of the prosthesis is embedded in the cortical bone marrow cavity. 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. 4. Femoral fracture For a serious complication that occurs later, more than 6 to 4 years after surgery. These fractures can be divided into three types depending on the location of the fracture and the method of treatment. Type 1: The fracture occurs in the intertrochanteric area. The treatment is relatively simple, rest in bed, without skin traction, early to get out of bed, and the crutches are heavy, and the average can be cured in 8 weeks. Type 2: The fracture occurs between the intertrochanteric line and the tip of the artificial femoral head and is also stable. Patients with fractures near the proximal end can be simply towed. The fracture line is close to the distal end. A long-handled artificial femoral head can be replaced and reinserted into the femoral canal to make it an internal fixation material. Type 3: The fracture occurs at the distal end of the tip of the artificial femoral head and is unstable. It is difficult to handle, and it is possible to use traction therapy or replace a long-handed femoral head, fill the bone cement in the medullary cavity, and fix the wire around the fracture. 5. Heterotopic bone The incidence of ectopic bone is about 30%, more than 6 weeks after surgery. For the influential hip function, no treatment is needed; for the mature ectopic bone that causes hip joint stiffness and hip dysfunction, surgical resection can be considered.

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