Abstract The fracture of the prosthetic stem after prosthetic replacement of femoral head is not rare. In this study, the photoeastic instrument was used to study the stress distribution on the prosthetic stem following its insertion and to analyse the factors influencing the fracture of the stem. Through the examination of 9 places in 8 cases, it was found that:(1) The removal of femoral calcar and the inframedullary filling of the bone cement directly influenced the stress distribution. (2) The valgus or varus condition of the prosthesis would lead to stress concentration on the stem. (3) Once lossening of the prosthesis occured it would change the preliminary installingstress distribution in the upper femur which would lead to fatigue fracture. Ths experimental data and clinical observation would provide scientific basis forthe prevention of fracture of prosthetic stem following prosthetic replacement of femoral head.
After freatment of prosthesis replacement for 12 malignant tumer of the proximal humoral werereported. The operation were performed after the indications and methods of treatment had beendefined. All of the 12 cases were followed-up, in the average of 8 yeare. On functional evaluation , 8cases had satisfactory result , but per in 1 cases and 3 cases died from recurrence or metastasis withinfive years. The indieation of the procthetic replantation, the complications, and revision weredisecused.
Objective To analyze the causes and the reoperation therapies after salvage limb surgery with prosthesis for bone tumors. Methods The retrospective analysis was performed on 85 patients undergoing the limb salvage operation with prosthetic replacement for tumors from January 1994 to December 2004. Ofthe patients, 21 (13 males and 8 females, aged 18-58 years) underwent reoperations for various reasons. All the diagnoses were pathologically confirmed(10 patients with osteosarcoma, 4 with chondrosarcoma, 5 with giant cell tumor of the bone, 2 with osteofibrosarcoma). The distal femur was involved in 9 patients, proximal tibia in 8, proximal femur in 2, proximal humerus in 1, and acetabulum in 1. According to the Enneking surgical grading system, there were 5 patients in ⅠB and 16 in ⅡB. The time between the first operation and the reoperation was 2 weeks to 20 years. The common reasons for the reoperation were tumor recurrence in 8 patients, prosthetic loosening in 5, no healing of the incision in4,joint dislocation in 3, and implant fracture in 1. The amputation and the prosthesis revision were respectively performed on 6 patients, extensive resection ofthe tumor on 3, the myo-skin flap translocation on 4, internal hemipelvectomy without reconstruction on 1, and open reduction on 1.Results The follow-up in18 patients for 1-5 years (average, 3 years and 4 months) revealed that 4 patients died of osteosarcoma with pulmonary metastasis. The other 14 patients had no tumor recurrence or loosening of the prosthesis, and the incisions healed well. The assessment on the joint function was performed on 13 of the 18 patients and the results were as follows: excellent in 2 patients, good in 5, fair in 4, and poor in 2, with a satisfaction rate of the reoperation with limb salvage of 84.6%and an excellent-good rate of 53.8%. Conclusion Tumor recurrence is the most common reason for the reoperation after the limb salvage with prosthesis for tumors, and loosening of the prosthesis is an important reason, too. By therules of the bone tumor limb savage, the limb salvage operations can also beperformed, which can achieve a satisfactory result of the limb function.
Objective To summarize the clinical outcome of the Ribbed anatomic cementless total hip arthroplasty (THA) in the treatment of hip-joint disease. Methods From January 2001 to June 2005, 34 patients(38 hips) with hip-joint disease were treated with Ribbed anatomic cementless THA. Their ages ranged from 29 to 55 years with an average age of 42.7 years.The disease course was from 3 to 18 years. Among these cases, there were 7 cases (7 hips) of femoral neck fracture, 5 cases(5 hips) of traumatic arthritis after fracture of acetabulum, 15 cases(16 hips) of necrosis of the femoral head and 7 cases(10 hips) of ankylosing spondylitis. Four patients were operated on both hip joints. The average Harris hip score was 38.6(25-57) before operation. Results Twenty-one patients(23 hips) were followed up 861 months with an average of 35 months. The Harris hip score was 76-98 after operation with an average of 92.3, showing significant difference when compared with that before operation(Plt;0.05). The excellent and good result was achieved in 93.5 % of patients. Radiographs showed no prosthetic osteolysis and no evidence of loosening. Pain in the thigh occurred in 4 patients,and it can be relieved by using nonsteroid antiinflammatory drug. Conclusion Ribbed anatomic cementless THA has good clinical and radiographic results in treating patients with hip-joint disease.
Objective To study the operative effect and complication of the prosthesis replacement of the proximal humerus with malignant tumor. Methods From October 1998 to August 2003, the prosthesis replacement was performed to treat the proximal femur with malignant tumor in 4 patients, including 2 patients with osteosarcoma (Enneking staging,ⅡA) and 2 patients with giancell tumor of the bone (ⅡA,ⅡB). By the International Society of Limb Salvage(ISOLS) criterion, the 2 cases of osteosarcoma were preoperatively scored as 4 and 5 points, and 2 cases of giant cell tumor of the bone were scored as 9 and 11 points. The patients’ psychological conditions as well as their limb pain, shape, locality, activity, and function werealso observed. Results The follow-up for 24-58 months (mean, 44 months) showed that there was no local recurrence or infection in all the patients except onepatient who had the loosening of the screws for the fixation 17 months after operation and had no treatment. After operation, all the patients had a better postoperative extention angle from 22° to 41°(mean, 25°), bending angle from 29° to 80°（mean, 35°）, abduction angle from 5° to 28°, and circumgyrate angle from 15° to 22° in their shoulder joints. However, the shoulder joint function was still unstable to some extent and the joints had a decreased strength. By the criterion formulated by the ISOLS, the postoperative score for assessing the 2 patientswith osteosarcoma was increased by 16 points when compared with the preoperative score; the score for the 2 patients with giant cell tumor of the bone was increased by 9.5 points.Conclusion The prosthesis replacement to treat the malignant tumor of the proximal humerus is the good method of choice and has a good therapeutic result; however, there are more complications and so the method should be cautiously employed in the clinical practice.
Objective To observe the effect of biological fixation of femoral stem prosthesis with multilayer macropores coating by combined use of autologousbone grafting. Methods The reconstructing femoral stem prostheses were designed personally, proximal 2/3 surfaces of which were reformed by thick multilayer stereo pore structure. Twentyfour adult mongrel canines underwent right femoralhead replacement and were divided randomly into two groups. The autogenous bonemud of femoral head and neck were not used in the control group. The histologicexamination, roentgenograms and biomechanical test were carried out in the 1st,3rd and 6th month after operation to observe the bone formation and fixation inthe exterior and interior sides of the prostheses. Results Onthe whole view,bone reconstruction occurred in experimental group in the 3rd and 6th month. Roentgenograms also proved to be superior to the control group. Histological examinationshowed that both the maximum bone inserting depth（μm） and average engorging ratio(%) of newly formed bone in experimental group surpassed those in the control group. The maximum shear strength of prosthesisbone interface in experimental group was significantly higher than that in the control group（Plt;0.01）. Conclusion Intensity of biological fixation can be strengthened remarkably by using femoral stem prothesis with multilayer macropores coating by combined use of autologous bone grafting.
Objective To improve the accuracy of the acetabular component placement using the nonimage based surgical navigation system. Methods Twenty-three patients (14 males, 9 females; age, 28-55 years;26 hips）with hip disease underwent the total hip arthroplasty (THA) using the nonimage based surgicalnavigation system from February 2004 to April 2006. Rheumatoid arthritis was found in 3 patients (3 hips), necrosis of the femoral head in 6 patients (6 hips), and osteoarthritis in 14 patients (16 hips). All the patients were randomly divided into the following 2 groups: the navigated group (11 patients, 13 hips), treated by THA using the nonimage based surgical navigation system; and the control group (12 patients, 13 hips), treated by the traditional THA. According to thedesign of the study, the acetabular component was placed in the best inclination angle (45°) and the anteversion angle (15°). The postoperative component position was examined. Results No fracture, dislocation, infection or injury to the sciatic nerve was found. In the navigated group, the inclination and the anteversion reached 15.4±1.4° and 45.5±1.3°, respectively. In the control group,the inclination and the anteversion were 13.9±7.6° and 43.7±6.4°, respectively. The inclination difference was considered statistically significant (Plt;0.01). All the patients were followed up for 10-40 months,averaged 26 months. In the navigated group, the postoperative average Harris hip score was 95 (range,85-110), with an excellent result in 11 hips and a good result in 2 hips. In the control group, the postoperative average Harris hip score was 92 (range,75-110), with an excellent result in 9 hips, a good result in 3 hips, and a fair result in 1 hip. The Harris hip score difference was considered statistically significant (Plt;0.05). There was a significantly better result obtained in the navigated group than in the control group. Conclusion The acetabular component can be implanted accurately by the nonimage based surgical navigation system, which can reduce the incidence of the loosening of the prostheses and has an important value in clinical practice.
OBJECTIVE To review the history and current status of total wrist arthroplasty. METHODS The original articles about wrist arthroplasty in recent years were reviewed. RESULTS The properties of wrist prosthesis of different generations were reviewed, with the emphasis on the prosthesis design and biomechanical behaviours. The surgical techniques, complications and salvage procedures were also discussed. CONCLUSION Although wrist arthrodesis is highly successful in treating the end-stage wrist arthritis, total wrist arthroplasty using well-designed prosthesis remains an alternative for the patients with special demands of hand functions.