Objective To study the effect of vancomycin-loaded polymethylmethacrylate (VCMPMMA) in the treatment of an experimental hemiprosthetic hip infectionof rabbits. Methods The infected hemiprosthetic hip joints of the rabbits underwent debridement and one-stage revision arthroplasty. Requested by the “fixed” method, 24 rabbits were equally divided into 2 groups: the control group and theexperimental group. The prostheses were fixed with PMMA in the control group, but with VCM-PMMA in the experimental group. X-ray films were taken immediately after operation, and then 4, 8, and 12 weeks after operation. The C reactive protein (CRP) and the erythrocyte sedimentation rate (ESR) were measured before operation, then measured 1, 3, and 7 days after operation, and then 2, 4, 8, and 12 weeks after operation, i.e., they were measured at the above 8 time points. All the rabbits were sacrificed 12 weeks later. The cure rate of the infection was determined by the blood culture for the corresponding bacteria and the Rhodamine-labeled anti-Staphylococcus epidermidisimmune serum staining. Results The X-ray films revealed that6 hemiprosthetic hip joints were dislocated in the control group, but 3 in the experimental group; 58.3% and 16.7% of the hemiprosthetic hip joints were reinfected in the control group and the experimental group, respectively. At 8 weeks in the control group, the serum CRP level decreased to a greater extent than that measured at the time of debridement, but in the experimental group just at 2 weeks （Plt;0.01）. ESR remained elevated in the control group, but at 4 weeks ESR were significantly lowered compared with that measured at the time of debridement（Plt;0.01）. The test results for the pathogenic organisms revealed that the re-infection incidences were respectively 58.3% (7/12) and 16.7% (2/12) in the control group and the experimental group, with the successful revision rates of 41.7% and 83.3% respectively in the above 2 groups. The light microscopy revealed that therewas a heavy infiltration by the inflammatory cells in the reinfected tissues, but there was a proliferation of the fibrocytes in the tissues of the cured patients. Conclusion Onestage revision arthroplasty can significantly promote the control of the hemiprosthetic hip joint infection in rabbits by the use of VCM-PMMA.
The orientation of the acetabular cup in hip joint anteroposterior radiograph is a key factor in evaluating the postoperative outcomes of total hip arthroplasty (THA). Currently, measurement of the acetabular cup anteversion angle primarily relies on manual drawing of auxiliary lines by orthopedic surgeons and calculations using scientific calculators. This study proposes an automated computer-aided measurement method for the acetabular cup anteversion angle based on hip joint anteroposterior radiograph. The proposed method segments hip prosthesis images using an improved Otsu algorithm, identifies feature points at the acetabular cup opening by combining circle-fitting theory and the cup’s geometric characteristics, and fits an ellipse to the cup opening to calculate the anteversion angle. A total of 104 hip joint anteroposterior radiographs, including 71 right-sided and 81 left-sided prostheses, were analyzed. Two orthopedic surgeons independently measured the postoperative anteversion angles, and the results were compared with computer-generated measurements for correlation analysis. Spearman and Pearson correlation analyses demonstrated significant correlations between the proposed method and manual measurements for both the right group (r = 0.795, P < 0.01) and the left group (r = 0.859, P < 0.01). This method provides a reliable reference for orthopedic surgeons to assess postoperative prognosis.
The stress distribution and different abduction angles have a close relation to the hip joint. The purpose of this study is to provide biomechanical evidence for the treatment or precaution of hip joint injuries. A three-dimensional model of the hip was established through a series of processing based on the normal human hip joint computed tomograph (CT) image data which were applied to reverse engineering software Mimics14.0 in this study. Firstly, a three-dimensional finite element model was generated with meshing and assigned material and then it was imported into the finite element analysis software Ansys13.0. At last the stress at the femoral neck was solved, computed and analyzed in the positive orthostatic position with 7 hip abduction angles of the hip joint: 0°, 5°, 10°, 15°, 20°, 25°, and 30°, respectively. The results showed that the stresses of femoral neck and outer region were obviously higher than those of front and rear area of the neck of femur in the upright position or abduction of a different angle. With the increase of abduction angle, femoral neck in front of the regional stress value basically unchanged and rear area decreased, but the more obvious changes occurred in the outer region although the stress of inner and outer area also increased gradually. The hip abduction may cause changes in stress distribution because of the femoral neck stress mostly concentrated in the inner and outer cortex, and therefore it has an important role in guiding for hip surgery injury patients to choose the most reasonable solutions and prevention initiatives.
In order to help a surgeon to determine a proper canal filing cutting path in a hip replacement operation conveniently, this paper presents a kind of probe with combined structure. Firstly, the doctor can use this kind of combined probe to choose canal filing cutting path. Then, the doctor can use computer to guide the surgeon to file femoral cavity along the selected canal filing cutting path. Through hip replacement corpse experiments, filing effects and used time of using combined probe group and separate control group were analyzed. The experiment results showed that the methods introduced in this paper could lower the difficulty of hip replacement operations, improve the implantation of hip stem prostheses further, and reduce the incidence of surgical complications.
ObjectiveTo explore the clinical effect of total hip arthroplasty (THA) in the treatment of old central dislocation of the hip joint. MethodsBetween January 2010 and June 2014, 21 patients (21 hips) with old central dislocation of the hip joint underwent THA and autologous bone graft for acetabulum reconstruction. There were 13 males and 8 females, aged 60-75 years (mean, 67.4 years). The left hip was involved in 12 cases and the right hip in 9 cases, with a disease course of 1-20 years (mean, 9.6 years). The causes were falling from height in 6 cases, traffic accident in 9 cases, crushing in 4 cases, and others in 2 cases. Hip pain, limited activity, and lameness were the main clinical symptoms. Preoperative Harris score was 32.95±2.06 and visual analogue scale (VAS) was 8.14±0.73. ResultsPrimary healing of incision was obtained in all patients. The patients were followed up 1.9-6.4 years (mean, 4.6 years). The X-ray films showed bone graft fusion at 4-24 months (mean, 12.5 months); there were no complications of grafted bone absorption, osteolysis, and infection. During follow-up, no prosthetic loosening or sinking, and no translucent zones around the prosthesis were observed. Harris score was significantly improved to 87.67±2.01 at 1 week and 92.10±1.95 at 1 year; and VAS score was significantly decreased to 2.57±0.81 at 1 week and 0.19 ±0.51 at 1 year (P < 0.05). ConclusionTHA is an effective surgical treatment for old central dislocation of the hip joint, because it can restore normal hip rotation center and reconstruct the hip joint function.
ObjectiveTo discuss the effectiveness of the modified Hueter direct anterior approach in treatment of Pipkin typeⅠ and Ⅱ femoral head fractures.MethodsBetween September 2014 and May 2016, 12 patients with Pipkin type Ⅰ and Ⅱ femoral head fractures were treated with the modified Hueter direct anterior approach. There were 8 males and 4 females, aged from 32 to 60 years (mean, 40.2 years). The disease causes included traffic accident injury in 9 cases and falling from height injury in 3 cases. According to Pipkin typing, 8 cases were rated as type Ⅰ and 4 cases as type Ⅱ. The interval of injury and admission was 2-28 hours (mean, 7.2 hours). Reduction was performed in all patients within 6 hours after admission, and then bone traction was given. The operation was performed in 3-7 days (mean, 4.3 days) after redution. The modified Hueter direct anterior approach was applied to expose and fix femoral head fractures by Herbert screws compressively. The operation time and intraoperative blood loss were recorded, and the effectiveness was evaluated according to the Thompson-Epstein scale at last follow-up.ResultsThe operation time was 80-130 minutes (mean, 97.5 minutes), and the intraoperative blood loss was 100-200 mL (mean, 130.2 mL). All fractures achieved anatomical reduction and successful fixation. All 12 patients were followed up 12-32 months (mean, 24.3 months). All patients achieved bone union in 15-20 weeks (mean, 16.3 weeks) and no wound infection, lateral femoral cutaneous nerve injury, osteonecrosis of the femoral head, or heterotopic ossification occurred. Traumatic arthritis occured in 3 patients. According to the Thompson-Epstein scale at last follow-up, the results were excellent in 5 cases, good in 5 cases, fair in 2 cases, and the excellent and good rate was 83.3%.ConclusionThe modified Hueter direct anterior approach has the advantages of clear anatomic structure, less trauma, and shorter operation time, and it can effectively expose and fix the Pipkin typeⅠ and Ⅱ femoral head fractures.
Based on the biomechanical simulation curve of OpenSim, an open source software of biomechanical model, a spherical exoskeleton parallel mechanism with two degrees of freedom for hip joint is proposed in this paper for the rehabilitation therapy of patients with impaired leg motor function or elderly people with walking dysfunction. Firstly, the parallel mechanism is modeled and the position inverse solution of the parallel mechanism is obtained using inverse kinematics analysis. The velocity analysis expression of the mechanism is derived by deriving the inverse kinematics solution. The model is imported into the mechanical system dynamics analysis software ADAMS and matrix processing analysis software MATLAB to carry out simulation experiments. The correctness of the velocity analysis is verified by comparing the velocity simulation results of the two methods. Then, three singular types of the mechanism are analyzed according to the obtained Jacobian matrix. According to the inverse solution of the mechanism, the reachable workspace of the mechanism is obtained by programming in MATLAB with given mechanism parameters and restriction conditions. Finally, the prototype platform is built. The experimental results show that the exoskeleton hip joint using this parallel mechanism can satisfy the requirement of rotation angle of human hip joint movement, but also can be good to assist patients with leg flexion-extension movement and adduction-abduction movement, and it is helpful to carry out corresponding rehabilitation training. It also has theoretical significance and application value for the research work of human hip exoskeleton parallel mechanism.
Objective To compare the bone resorption between the proximal fixation of the anatomique benoist giraud（ABG） hip and the distal fixation of the anatomic medullary locking（AML） hip by the medium-term X-ray films, and to evaluate the clinical results of the two prostheses. Methods From January 1992 to December 1996, 298 patients (396 hips) underwent the total hip arthroplasty at Wilson Hospital in Korea. In 125 patients, 176 hips were ABG hips, including 103 avascularnecrosis hips, 57 dysplasia hips, and 16 other diseased hips; In the other 173 patient the remaining 220 hips were AML hips, including 147 avascular necrosis hips, 65 dysplasia hips, and 8 other diseased hips. The A-P X-ray imagings were followed up for 5-12 years averaged 8 years, and were compared with the immediate postoperative X-ray imagings. The bone resorption area was measured and the bone resorption cases were recorded according to the Gruen zone obsesvation. Results During operation, 2 ABG hips and 5 AML hips were cracked at the femoral diaphysis; 3 ABG hips and 1 AML hip were cracked at the metaphysis; 6 ABGhips and 3 AML hips were fractured because of trauma after operation; among them, 2 ABG hips needed the stem revision and the remaining hips underwent the openreduction and the internal fixation. During the follow-up, 9 ABG hips were revised, 7 hips of which developed the aseptic loosening. No AML hip was revised, but 3 AML hips developed the aseptic loosening. The bone resorption pattern in theABG and AML hips was similar. The bone resorption occurred most commonly in theGruen zones 1 and 7, and it extended from the metaphysis to the diaphysis. In the Guren zones 2, 5, 6 and 7, there were more AML hips than ABG hips that developed the bone resorption. The bone resorption area around the AML hip was larger than that around the ABG hip. Conclusion The stress shielding bone resorption usually occurs proximally to the union area of the bone and the prosthesis. The ABG prosthesis is a proximal fixation prosthesis, therefore, the stress shielding bone resorption can be reduced. The bone resorption around the AML prosthesis develops slowly within 10 years after operation. The stress shielding bone resoption may reach the summit within 10 years and it will not develop endlessly, so the prosthesis will be stable for a long time. The probabilityof the bone resorption in the ABG prosthesis is smaller than that in the AMLprosthesis. The bone resorption around the AML prosthesis may develop slowly after 10 years and will not affect the stability of the prosthesis for a long time.
Objective To evaluate the effectiveness of multiple small-diameter drilling decompression combined with hip arthroscopy for early oeteonecrosis of the femoral head (ONFH). Methods Between March 2010 and December 2013, 91 patients with early ONFH were treated with the operation of multiple small-diameter drilling decompression combined with hip arthroscopy in 39 cases (53 hips, group A) or with drilling decompression alone in 52 cases (74 hips, group B). The patients in 2 groups had obvious hip pain and limited motion before operation. There was no significant difference in gender, age, etiology, effected side, stage of osteonecrosis, and preoperative Harris score between 2 groups (P>0.05). Results All operations succeeded and all incisions healed by first intention. The operation time was significantly longer in group A [(73.3±10.6) minutes] than in group B [(41.5±7.2) minutes] (t=8.726, P=0.000). Temporary of sciatic nerve apraxia after operation occurred in 2 patients of group A, and no complication occurred in other patients. Patients were followed up 24-52 months (mean, 39.3 months) in group A and 24-48 months (mean, 34.6 months) in group B. At last follow-up, the Harris scores were 83.34±8.76 in group A and 76.61±9.22 in group B, showing significant differences when compared between 2 groups (t=–4.247, P=0.029) and when compared with preoperative values in 2 groups (t=–10.327, P=0.001; t=–8.216, P=0.008). X-ray films showed that the collapse of the femoral head was observed in 6 hips (1 hip at stage Ⅰand 5 hips at stage Ⅱ) in group A, and in 16 hips (4 hips at stageⅠand 12 hips at stage Ⅱ) in group B; and hip arthroplasty was performed. The total effective rates were 88.68% (47/53) in group A and 78.38% (58/74) in group B, respectively; showing significant difference between 2 groups (χ2=5.241, P=0.041). Conclusion Multiple small-diameter drilling decompression combined with hip arthroscopy is effective in pain relief, improvement of hip function, slowing-down the process of femoral head necrosis, delaying the need for total hip arthroplasty in patients with early ONFH.
ObjectiveTo evaluate hip function and reinfection of the patients with hip infection sequelae after total hip arthroplasty (THA) treatment.MethodsA clinical data of 31 patients (31 hips) with hip infection sequelae, who were treated with THA between June 2010 and May 2017, was retrospectively analyzed. There were 18 males and 13 females, with an average age of 46.1 years (range, 20-71 years). There were pyogenic infection in 17 cases, tuberculous infection in 9 cases, and unknown source of infection in 5 cases. The average time from infection to cure was 13.9 months (range, 6-25 months). The average time from cure to operation was 23.4 years (range, 6-58 years) for patients with confirmed source of infection. According to Kim classification, 12 cases were rated as typeⅠ, 9 as typeⅡ, and 10 as type Ⅲ. There were 21 cases of osteoarthritis after dysplasia, 7 cases of pathologic dislocation, and 3 cases of hip ankylosis. After operation, the infection was assessed by physical signs and laboratory tests; X-ray film of the hip was taken to assess the skeletal structure of the hip and infectious lesion; the length of the lower limb was measured, and the function of the hip joint was evaluated by Harris score.ResultsAll patients were followed up 10-63 months (mean, 34 months). The result of bacterial culture was negative. The incisions healed by first intention. The sciatic nerve stimulation occurred in 1 case and posterior dislocation of the joint occurred in 1 case after operation. There was no recurrence of infection and no aseptic loosening of the prosthesis. According to Harris score, the function of the hip was rated as excellent in 8 cases, good in 19 cases, and fair in 4 cases at last follow-up; and the excellent and good rate of hip joint function was 87%. X-ray films showed no patchy bone density reduction, spot hardening, or light areas. The length of affected limb was not fully equal with the unaffected limb in 5 cases, and the difference between two sides ranged from 0.4 to 1.3 cm (mean, 0.6 cm). At last follow-up, all patients had no obvious claudication or sensation of unequal length.ConclusionTHA can obtain satisfactory hip function and has low risk of infection recurrence for the patients with hip infection sequelae, who were assessed as the hip infection in a dormant state.