| Total hip arthroplasty has become the most effective treatment of severe hip diseases such as femoral neck fractures, femoral head necrosis, hip dysplasia, osteoarthritis. It is widely recognized in alleviating pain, improve joint function, restore hip stability and reduce the complications in bed, and it is also one of the most successful surgeries in department of orthopaedics. Long length of incision, heavy damage, long operation time and slow recovery are the characters of the traditional total hip arthroplasty. With the innovation and development of prosthetic materials and operative method improved, minimally invasive hip arthroplasty has become the common goal for both orthopedic surgeons and the patients. Minimally invasive is an new technology to gain better operation result by using the smallest trauma and youngest physiological interference to the operation. Minimally invasive hip arthroplasty has a lot of advantages, such as short incision(<10 cm), light damage to soft tissues and muscles, early postoperative functional exercise and rapid recovery. So it is widely used in clinical appliation and approved by orthopaedic doctors. But minimally invasive surgeries have higher requirements in the aspect of operation indication, artificial prosthesis materials, surgical techniques and perioperative management.Surgery complications of total hip arthroplasty include infection, lower limb deep vein thrombosis and pulmonary embolism, prosthesis dislocation or subluxation, prosthetic aseptic loosening, bone dissolution, fracture around the prosthesis, leg length discrepancy, heterotopic ossification, nerve vascular injury, hematoma, etc. Leg length discrepancy is one of the most common complications, and it is also the most common complaints of patient’s dissatisfaction in the clinical work. The dissatisfaction of leg length discrepancy was the second cause of lawsuit of medical accident reason according to the reports of hip knee surgeons in the United States. Some scholars called this complication "a lawyer await". Equilibrium of lower leg length after hip arthroplasty has an important significance for hip joint surrounding soft tissue balance, joint function recovery, patients of postoperative effect and aesthetic satisfaction. The complications of leg length discrepancy include pelvic obliquity, back pain, limping, sciatica, prosthetic aseptic loosening, arthritis, and joint discomfort or pain. These problems will shorten the service life of the prosthesis, reduce the satisfaction to hip arthroplasty surgery. How to control the leg length discrepancy of the hip arthroplasty in the operation is hard to solve for orthopedic surgeons.Imaging measurement is the gold standard for clinical measuring leg length discrepancy. Preoperative radiographs were taken from an anteroposterior view of the pelvis, then the templates were used to determine the height of the femoral neck osterotomy and the potential correct sizes for both the acetabular and femoral components of the prostheses. This method can reduce the incidence of leg length discrepancy. But there is no accuracy measurement which pressure the procedure acting as planned. Higher or lower femoral neck osterotomy which affecting the type and the location of the prostheses, measurement inaccuracy, these will result in leg length with higher incidence.Studied in this paper, we evaluated the femoral neck anatomical features through basic research, designed intraoperative limb-length measurement and osteotomy guide device in total hip arthroplasty, and evaluated the effective through clinical application study. Part one Basic research of intraoperative limb-length measurement andosteotomy guide device in total hip arthroplastyObjective:Through the study of the CT scanning to obtain relevant data of the femoral neck, on this basis, design the femoral neck osteotomy guide for assisting femoral neck osteotomy during the operation. We designed osteotomy test to femur specimens for evaluating the accuracy of femoral neck osteotomy guide. Combined the femoral neck osteotomy guide and measurement ruler, we designed the intraoperative limb-length measurement and osteotomy guide device, which would be used to reduce the incidence of leg length discrepancy.Methods:The experiment divided into four parts: ①Record the femoral neck shaft angle, anteversion angle, width of femoral lesser trochanter, and width of femoral neck by CT scan and vernier caliper measurement.②According the measurement, we choose femur specimens and designed model of femoral neck osteotomy guide. Then we tested its fitting on 128 femur specimens.③Evaluate the accuracy of osteotomy by the experiment of cutting bones by femoral neck osteotomy guide. ④Combined the femoral neck osteotomy guide and measurement ruler, we designed the intraoperative limb-length measurement and osteotomy guide device.Results:①The average of femoral neck shaft angle is 126.60°±5.98°, the average of anteversion angle is 13.10°±1.92°. The average of width of femoral lesser trochanter is 16.4±2.30 mm by CT scan, and 16.4±2.30 mm by manual measurement, there is no statistic difference t=1.939,P=0.062>0.05. The average of width of femoral neck is 27.2±2.20 mm by CT scan, and 27.5±3.20 by manual measurement, there is no statistic difference t=-0.330,P=0.743>0.05. ②The average of osteotomy height is 14.95±0.51 mm in the group of femoral neck osteotomy guide application, the average of osteotomy height is 14.20±1.51 mm in the group of experience osteotomy. There exits statistic difference t=2.107,P=0.046<0.05.Conclusion:By CT measurement and manual measurement, there is no significant difference in femoral neck anatomical measurement. The accuracy of cutting bones through the femoral neck osteotomy guide is higher than experience osteotomy. We designed the intraoperative limb-length measurement and osteotomy guide device.Objective : Total hip arthroplasty(THA) is a common last-resorttreatment for hip disease, but postoperative patients often complain ofdiscrepancies in leg length. This study introduces a device designed toincrease the precision of the femoral neck osteotomy and reduce the incidenceof leg length discrepancy.Methods:Forty-eight patients undergoing THA were divided into twogroups, with and without the use of the femoral osteotomy guide. Alloperations were performed through a posterolateral approach. Differences inleg length were recorded before and after the operation. Measurements werealso made to compare the preoperative plan with the actual amount of boneremoved.Results:The mean average difference in femoral neck resection heightwas 0.84 mm when using the osteotomy guide and 1.69 mm without the guide.Discrepancies in postoperative leg length were 5.45 mm and 13.37 mm in thegroups with and without the guide, respectively.Conclusion : The femoral neck osteotomy guide is an effectivelyauxiliary tool for increasing the accuracy of bone resection in arthroplastyusing the posterolateral approach.Part three Clinical application study of intraoperative limb-lengthmeasurement and osteotomy guide device inhemiarthroplasty for treating femoral neck fractureBackground: Limb length discrepancy is one of the most commoncomplications after hip arthroplasty. We developed a device- intraoperativelimb-length measurement and osteotomy device(ILMOD), and applied it topatients who were treated with hemiarthroplasty for femoral neck fracture toimprove Limb length discrepancy by providing an accurate osteotomy duringhemi-arthroplastyMethods: Between April 2012 and October 2013, 65 patients weretreated with hip hemiarthroplasty for femoral neck fracture at our traumacenter. 31 patients met the inclusion criteria and were randomly enrolled into two groups ILMOD group and control group. All operations were performed Part two Clinical application study of femoral neck osteotomy guide fortotal hip arthroplasty through a posterolateral approach. Hemiarthroplasty in this study were performed with cement fixation. Treatment-related measurements such as the operation time, times of osteotomy and the volume of intra-operative blood loss were collected. In both groups, postoperative(1 month) radiologic analysis on anteroposterior weight-bearing pelvic view was performed to evaluate limb-length discrepancy.Results: The results showed significant improvement in limb length discrepancy in ILMOD group, and analysis of postoperative radiographs found the mean length difference is 2.1±1.9 mm in ILMOD group compared to 8.8±5.1 mm in control group. No complications associated with the use of the device were reported, and none of the patients complained of the discomfort related to limb-length discrepancy after surgery. The average intra-operative time was significantly longer in ILMOD group(84.9±9.2 min) compared to that in control group(70.9±10.2 min).Conclusions: The ILMOD is an effective device that can be used easily for intraoperative limb length measurement and osteotomy during hemiarthroplasty. The application of device can improve the femoral neck bone cutting accuracy, reduce the damage to the soft tissues, at the same time in intraoperative rapid measuring the length of the head and neck, to evaluate lower limb length, reduce the incidence of leg length discrepancy. This method is applicable with post-lateral approach, and the technique could also be used in total hip arthroplasty. |
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