Architectural changes in occurring in the proximal femur (resorption) after total hip arthroplasty (due to stress shielding) continues to be a problem. In an attempt to reduce these bony changes the concept of short and femoral neck sparing stem designs have been advocated. The purpose of this study was to evaluate the early clinical and radiological results, especially stem fixation and bone remodeling of proximal femur after total hip arthroplasty. A total of forty-five patients (fifty-four hips) were included in the study. There were twenty men and twenty-five women. The mean age at the time of operation was 53.9 years (range, twenty-six to seventy-five years). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients one week after operation and at the final follow-up examination. The mean follow-up was 1.3 years (range, one to two years). The mean preoperative Harris hip score was 45 points (range, 15 to 48 points), which improved to a mean of 96 points (range, 85 to 100 points) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. One hip (2%) required open reduction and fixation with a cable for calcar femorale fracture. Bone mineral densitometry revealed a minimal bone remodeling in the acetbulum and proximal femur. The geometry of this ultra-short anatomic neck sparing cementless femoral stem has proved to provide effective initial stability even without the diaphyseal portion of the stem. We believe that femoral neck preservation and lateral flare of the stem provide an axial and torsional stability and more natural loading of the proximal femur.
Modified posterior approach preserving short external rotators would be able to contribute greatly to prevent dislocation after total hip arthroplasty. We modified the posterior approach to the hip by preserving the external rotator muscles in order to enhance joint stability after total hip arthroplasty in patients with osteonecrosis of the femoral head. The aim of the this study was to determine the influence of external rotator preserving posterior approach in primary total hip replacement on early dislocation and clinical outcome. Three hundred sixty-four primary total hip replacements were divided into two groups based on how the external rotators were treated at surgery. External rotator preservation (Group 1, 165 hips) group was compared with reattachment (Group 2, 199 hips) group by evaluating the clinical and radiographic outcome at one year postoperative. Anteversion was significantly less in Group 1 as compared to Group 2 (P <
0.001). There was no significant difference in inclination between the groups (P >
0.05 in all comparisons). No dislocations were found in 165 hips with external rotator preservation whereas dislocations was noted in 11 (3.9%) in Groups 2, respectively. Group 1 had the higher mean Harris hip score (97.2±2.9 points) as compared with Group 2(94.9±3.4). The results of this study showed that external rotators could play an important role in preserving joint stability after total hip arthroplasty in patients with osteonecrosis of the femoral head. It can be implied that this modified posterior approach would be able to contribute greatly to prevention of dislocation, and improve clinical outcome after total hip arthroplasty.
There was used cement in first generation total ankle arthroplasty, but first generation of ankle arthroplasty was abandoned because of aseptic loosening of component. For the treatment of aseptic loosening of ankle arthroplasty, there had been many methods. One of methods of revisional ankle arthroplasty is the ankle arthodesis. The authors report a case of revisional ankle arthroplasty using allograft with hybrid external fixation. 45 year old male had surgery of cemented total ankle arthroplasty on his right ankle 20 years ago. He went to our clinics because of motionless and pain of his right ankle. He got the mild pain on his right ankle after 5 years surgery. His pain was managed by oral NSAIDS for 15 years. The pain was aggravated recently. There were osteophytes on posterior aspect of ankle joint and radiolucency around the implant, subtalar arthrosis at the radiograph. There was also sclerosis around the ankle joint. The authors decided revisional surgery. At the operative findings, we can see the loosening of talar and tibial component and large posterior osteophyte bridging between remained talus and tibial bone. There were no infection signs. After remove the implant, there was big space remained. For the regaining the limb length, we used femoral head allograft. The graft was fixed with 6.5 mm cannulated screws and addition fixed with ilizarov external fixation. Also additional auto bone graft from the osteophytes was applied. Compression over the ilizarov external fixation was done at the end of the operation. Weight bearing was allowed immediate after surgery. Ilizarov ring was removed 6 weeks after surgery. At the 3 months after surgery, bony union was obtained on radiographs. AOFAS score was improved from 30 to 70 6 mo after surgery. There was no pain on his right ankle. Patient satisfied with arthrodesis with allograft at final follow-up.
The purpose of this study is to compare the two prosthesis which were used for total ankle arthroplasty. From Sept. 2003 to Jun 2007, 13 patients and 14 ankles that could be follow up more than 2 years. Semiconstrained type (Group I, 7cases) and Unconstrained type (Group II, 7cases) were used for total ankle arthroplasty. Mean age was 63.2 year-old, 12 ankles are men and 2 ankles were women. Mean follow up periods were 31.1 months. The criteria to compare the clinical result were postoperative range of motion (ROM), AOFAS foot score and residual bone stock of medial malleolus. Postoperative ROM of group I was 37.5±7.1 degree and of group II was 51.4±8.9. Postoperative AOFAS score of group I was 76.1±13.8 and of group II was 86.0±5.7. Residual bone stock in medial malleolus of group I was 6.1mm±0.7 and of group II was 11.5mm±0.9. Total number of complication in our study was 9 cases. 3 cases were a malleolar fracture, two occurred at intra-operation, the other at follow-up period. Re-operation was done in 6 cases, 3 cases were calcaneal corrective osteotomy, 2 cases were resection of a heterotopic bone and one case was pedicular flap operation for skin problem. In our hospital, mobile bearing type prosthesis showed good result than a semiconstrained type in respect of ROM improvement and of residual bone stock in medial malleolus. AOFAS score between two groups showed no definite difference. But small number of patients and short term follow up period is a defect in our study, afterward more population and long term follow up period are needed.
The use of stem provides consistent component alignment with immediate stable fixation and protects grafted bone by reducing stress on metaphyseal area in revision total knee arthroplasty. One of major concern with use of stems involves stem tip pain in cementless diaphyseal engaging stem. The purpose of this study is to evaluate the effect of stem design and method of fixation on stem tip pain in revision total knee arthroplasty by finite element analysis. 3D finite element model of normal tibia was reconstructed from CT scan images of 26 year old male and the CAD model of revision total knee arthroplasty was developed using commercial software(CATIA®, Dassault system, USA, version 8.20). The tibia component models were assembled based on conventional surgical procedure. The design changes of stem such as the length, diameter and slot were performed and methods of fixation including press fit and coefficient of friction was considered. The contact pressure and von-Mises stress around the stem and the micromotion at the interface were evaluated for a 2000 N of external load by finite element analysis to investigate the effect of stem design and methods of fixation on stem tip pain. The longer length and larger diameter press fit stem significantly increase the contact pressure &
stress at the end of stem. The distal slot reduces the contact pressure &
stress at the end of stem. Less displacement between tibial component and bone was noted in the increased coefficient of friction. It would be better to avoid using press fit stem with extended length and larger diameter in revision total knee arthroplasty. More flexibility of stem tip would be favorable because of less concentration of stress. Stem fixation with higher coefficient of friction would be recommended for less displacement of tibial component. Stem with shorter length enough to engage proximal diaphysis, closer diameter of proximal canal and minimal press fit could be accepted to reduce stem tip pain if patient’s surgical anatomy such as bone loss and quality is tolerable in revision total knee arthroplasty.
We developed a modified posterior approach that preserved the short external rotator muscles to prevent dislocation after THA or BHA. The present study aimed to evaluate the effectiveness of short external rotator preserving posterior(ERP) approach for bipolar hemiarthroplasty in treatment of femoral neck fractures in patients with neurologic disorders. Between March 2004 and February 2006, we performed 187 cementless bipolar hemiarthroplasties for displaced femoral neck fractures on 36 patients with neurologic disorders, who were operated on by ERP approach (Group 1) and 151 patients without neurologic deficits, who were operated on by conventional posterolateral approach (Group 2). We compared operation time, the amount of postoperative blood loss, the early postoperative complication rates, the dislocation rate within 1 year, and duration of hospital stay between two groups. The amount of postoperative blood loss was significantly decreased in group 1(p <
0.01). There were no significant differences in mean operation time and early postoperative complication rate including wound problem, deep vein thrombosis or infection and duration of hospital stay. There was no dislocation after operation in group 1, but seven patient (4.6%) had dislocation in group 2. Nine patients (25.0%) died within postoperative 1 year in group 1 and twenty six patients (17.2%) died in group 2. Cementless bipolar hemiarthroplasty through ERP approach provides a favorable outcome for treatment of displaced femoral neck fracture in patients with neurologic disorders who is considered as high risk of dislocation. Also, it decreases the postoperative blood loss and the needs of postoperative abduction brace.
Recently, it has been reported that the posterior stabilised implant clinically used for the total knee replacement (TKR) may have a risk of failures caused by pressure and stress concentrated on the tibial post. Malalignment of the implant or variable loading applied to the implant are one of the major causes of the failure in posteriori stabilised TKR. The purpose of this study is to biomechanically analyse the effect of implant malalignment on the failure risk of the implant in posteriori stabilised TKR by estimating von-Mises stress on the implant. Finite element models of a knee joint and a posteriori stabilised implant were developed from 1mm slices of CT images and 3D CAD software, respectively. The posterior stabilised implant consists of a femoral component, a tibial post, and a tibial tray. The finite element models of TKR for the neutral alignment case as well as the different malalignment cases (3° and 5° of valgus and varus angulations, 2° and 4° of anterior and posterior tilts, and 3° of external rotation) were developed. Then, the von-Mises stress, which is which was chosen as the fracture risk parameter, acting on the implant were analysed by using CAE software. Loading condition at the 40% of one whole gait cycle such as 2000N of compressive load, 25N of anterior-posterior load, and 6.5Nm of torque was applied to the TKR models. The maximum von-Mises stresses were concentrated on the anterior region of the tibial post regardless of the oblique loadings. In the rotationally additional loading (3° of external rotation), excessive stresses occurred in the anterior medial and posterior lateral areas. The maximum stress was 18.3MPa in neutral position. The maximum stress increased by 10% in anterior tilt 2°, 15% in anterior tilt 4°, 25% in posterior tilt 2°, 54% in posterior tilt 4°, 116% in varus 3°, 262% in varus 5°, 318% in valgus 3°, 389% in valgus 5°, 6% in external rotation 3° compared with that in the neutral position case. In addition, 32.0MPa of maximum stress occurred on the posterior lateral area of the base component in rotationally additional loading. The results showed that the implant malalignment could accelerate the stress concentration on the anterior region of the tibial post as in the result of clinical study. In the case of additional rotation, high stress concentration on the anterior medial and posterior lateral areas as well as on the tibial base surface could generate wear or fracture of tibial post. From the additional rotation case, we can expect that higher conformity implant will generate higher stress concentrations than lower conformity implant even though we did not compare the effect of conformity ratio on the stress concentration in the tibial polyethylene component. This study showed that careful consideration of the implant malalignment would be necessary to improve the clinical outcome in the posteriori stabilised TKR.
One hundred twenty eight revision hip arthroplasties performed before Dec. 1995 using the Wagner self locking prosthesis were followed for five to ten years. Obviously, the shape of this revision prosthesis complements optimal primary stability; however, one must pay attention not to undersize the stem. Hence, the most significant feature contributing to this self-locking type is the accomplishment of appropriate canal filling when revision with optimum anchorage length of prosthetic component. According to the clinical and radiological data obtained from our midterm results, we confirm the excellent validity of this system for treating the advanced cases of bone resorption for revision. Obviously the classification based on the femoral bone deficiency by the AAOS and DGOT are well documented. Even though we agree with the recent concept of Bourne-Rorabeck that is worthwhile tending to revert to a simple, but practical classification based on the cancellous bone’s quality and the intactness of the cortical tube, we believe that four of Bourne-Rorabeck had better be five in order to be clearer. Furthermore, additional seven various cases series of recent for subsidence of the femoral components were included in this study. We beieve that the only contraindication is conversion from arthrodesis when the patient has long standing history of heavy plate and screws because of undue discrepancy of the stress shielding. Lastly, it is very unusual, however, we describe the operative technique which Wagner stem is inevitably removed.
The purpose this prospective, randomized clinical trial was to determine if unilateral or bilateral simultaneous total hip arthroplasty procedures resulted in a differing incidence of fat embolization, degree of hemodynamic compromise, levels of hypoxemia or mental status changes. Also, the incidence of fat embolization was compared between the cemented and cementless total hip arthroplasty in the patients with a unilateral- and bilateral simultaneous total hip arthroplasty. One hundred and fifty-six consecutive patients undergoing primary total hip arthroplasty were enrolled prospectively in the study after giving informed consent. The group consisted of fifty patients undergoing bilateral simultaneous total hip arthroplasty and 106 patients undergoing unilateral total hip arthroplasty. One hundred and three hips were cemented and 103 hips were cementless. To determine the hemodynamic changes and to detect the fat and bone marrow embolization, arterial and right atrial blood samples were obtained before implantation (baseline) and at one, three, five and ten minutes after implantation of the acetabular component. Also, arterial and right atrial blood samples were obtained at one, three, five and ten minutes after implantation of the femoral component. And then blood samples were obtained at twenty-four and forty-eight hours after the operation. Arterial blood pressure, right atrial pressure, arterial oxygen tension and carbon-dioxide tension were monitored at corresponding times. The presence of lipid was determined with oil red O fat stain and the presence of cellular contents of bone marrow was determined with Wright-Giemsa stain. The incidence of fat embolism was not statistically different (P=1.000) between the patients with a bilateral total hip arthroplasty (twenty seven patients or 54 per cent) and the patients with a unilateral total hip arthroplasty (fifty-two patients or 49 per cent). In the semiquantitative analysis of fat globules in both groups, there was no tendency to have a higher number of fat globules in the bilateral group than in the unilateral group. Also, the incidence of bone marrow embolization was not statistically different (P=0.800) between the patients with a bilateral total hip arthroplasty (eight patients or 16 per cent) and the patients with a unilateral total hip arthroplasty (fourteen patients or 13 per cent). There was no statistical difference (P=0.800) in the incidence of the presence of fat globule between the cemented total hip (thirty-four patients or 34 per cent) and the cementless total hip arthroplasty (forty-seven patients or 44 per cent). Also, there was no statistical difference (P=0.627) in the incidence of the presence of bone marrow cells between the cemented total hip arthroplasty (thirteen patients or 13 per cent) and the cement-less total hip arthroplasty (twelve patients or 11 per cent). Four patients with positive bone marrow cells had neurological manifestation. All of these four patients developed diffuse encephalopathy with confusion and agitation for about twenty-four hours. The present study confirmed that the incidence of fat and bone marrow embolization is similar in the patients with a bilateral simultaneous-and unilateral total hip arthroplasty as well as in the patients with cemented and cementless total hip arthroplasty. The patients with bone marrow cell emboli had a significantly lower arterial oxygen tension (p=0.022) and oxygen saturation (p=0.017) than the patients without bone marrow cell emboli. On the contrary, the number of fat globules did not affect the perioperative hemodynamic changes. Encephalopathy is related to the biochemical and/or mechanical changes by bone marrow cells.
We report our early Boston experience with the technique of Ganz, et al., for surgical dislocation of the hip, which provides a safe, powerful approach to certain major intraarticular hip problems. Materials and Methods: Forty-seven hips with various mechanical disorders have been treated using the Ganz technique of trochanteric flip osteotomy and anterior dislocation (JBJS 83-B: 1119-1124, 2001). Diagnoses include slipped epiphysis 14, Perthes 12, aspherical head/ anterior offset 12, dysplasia 14, multiple exostoses 2, other 3.Seven patients had simultaneous femoral oste-otomies; four had subcapital osteotomies for epiphys-iolysis. All patients had pain and limitation of motion preoperatively, and more than fifty percent had severe deformity and/or some arthrosis. Follow-up was six months to five years. Ages at surgery were eight to forty-eight years (mean twenty years). Results: The variety of pathologies render objective analysis difficult, though all patients reported greatly reduced pain and increased motion post operatively. Only five patients were totally pain free and had objectively totally normal hips. No patient felt unimproved. No patient had radiographic signs of osteonecrosis. Conclusion: Paralleling the Bernese experience of more than eight hundred cases, we find the Bernese technique of surgical dislocation to be a safe, effective tool for treating intra-articular hip pathology, increasing treatment possibilities for hip joint preservation. We anticipate greatly expanding its use in the future.
To evaluate the results critically of cemented total hip arthroplasty using a fourth generation cement technique and polished femoral stem, a prospective study was performed in patients under 50 years of age who underwent primary total hip arthroplasty. 55 patients (64 hips) were enrolled in the study (43 were male and 12 were female). Average age of patients was 43.4 years (21–50 years). Elite plus stems (DePuy, Leeds, UK) were cemented and cementless Duraloc cups (DePuy, Warsaw, IN.) were implanted in all hips. 22 mm zirconia femoral head (DePuy, Leeds UK) was used in all hips. All surgeries were performed by one surgeon (YHK). The diagnosis was osteonecrosis (43 hips or 67%), osteoarthritis (5 hips or 4%), O.A. 2° to childhood T.B. or pyogenic arthritis (4 hips or 6%), R.A, (3 hips or 5%), DDH (2 hips or 3%) and others (7 hips or 11%). The average F.U. was 7.2 years (6–8 years). The 4th generation cement technique was utilized including: medullary plug, pulsatile lavage, vaccum mixing of Simplex P cement; cement gun, distal centralizer and proximal rubber seal to pressurize cement. Thigh pain was evaluated using a visual analog scale (10 points). Clinical (Harris hip score) and x-ray follow-up was performed at 6 weeks, 3 months, 6 months, 1 year and then annually. Cementing technique was graded. Abductor moment arm, femoral offset, neck and limb length, center of rotation of hips, cup angle and anteversion were measured in all hips. Linear and volumetric wear were measured by software program. Osteolysis was identified. There was no aseptic loosening or subsidence of components. One hip was revised due to late infection. Incidence of thigh pain was 11% (7 hips). All thigh pain disappeared at 1 year postoperatively. Preoperative Harris hip score was 47.2 (7–67) points and 92.2 (81–100) points at the final F.U. Femoral cementing was classified as grade A in 50 hips (78%), grade B in 6 hips (9%), and grade C1 in 8 hips (13%). There was no cases in grades C2 and D. All bones had type A femoral bone. The average linear wear and annual rate were 1.25 and 0.21 mm, respectively. The average volumetric wear was 473.48 mm3. There was statistically significant relationship between the liner wear, age (under 40), male patient, and the cup angle. Yet there was no statistical relationship between the wear and Dx., wt., hip score, R-O-M, anteversion, anbductor moment arm, femoral offset, neck and limb length and center of rotation of hip. Osteolysis was identified in zone 7A in 6 hips (9%). No hip had distal osteolysis. Advanced cementing technique, polished improved stem design, strong trabecular bone, and utilizing a smaller head and thick polys greatly improved the mid-term survival of the implants in these young patients. Good cementing technique eliminated distal osteolysis and markedly reduced the proximal osteolysis. Yet high linear and volumetric wear of polyethylene liner remains to be a challenging problem.
To determine the results critically of cementless third generation prosthesis (proximal fit, porous coated, and tapered distal stem), a prospective study was performed only in Charnley class A patients under 50 years of age who underwent primary total hip arthroplasty. 50 patients (50 hips) were included in study (37 were male and 13 were female). Average age of patients was 45.4 years (26–50 years). IPS(Immediate Postoperative Stability) stems (DePuy, Leeds, UK) were implanted in all hips. Cementless Duraloc cups (DePuy, warsaw, IN.) were used in all hips. 22 mm zirconia femoral head was used in all hips. All surgeries were performed by one surgeon (YHK). The redominant Dx. was osteonecrosis (30 hips or 60%), O.A. 2° to childhood T.B. or pyogenic arthritis (8 hips or 16%) and others (12 hips or 24%). The average F.U. was 6.3 years (5–7 years). Thigh pain was evaluated using a visual analog scale (10 points). Clinical (Harris hip score) and x-ray follow-up was performed at 6 weeks, 3 months, 6 months, 1 year and then annually. Linear and volumetric wear were measured by software program. Abductor moment arm, femoral offset, neck and limb length, center of rotation of hips, cup angle and anteversion were measured and the results were compared between normal and operated hips. All hips had satisfactory fit in A-P and lateral planes. There was no aseptic loosening or subsidence of components. Incidence of thigh pain was 14% (7 of 50 hips). All thigh pain disappeared at 3 years postoperatively. Preoperative Harris hip score was 52.3 (7–64) points and 92.9 (80–100) points at the final F.U. The values of abductor moment arm, femoral offset, neck and limb length, center of rotation of hips, cup angle and anteversion of operated hips were comparable to normal unoperated hips. The average linear wear and annual wear rate were 1.25 and 0.21 mm, respectively. The average volumetric wear was 473.48 mm3. There was statistically significant relationship between the liner wear, age (under 40), male patient, and the cup angle. Yet there was no statistical relationship between the wear and Dx., wt., hip score, R-O-M, anteversion, abductor moment arm, femoral offset, neck and limb length and center of rotation of hip. Osteolysis was identified in zones 1A and 7A in 4 hips (8%). No hip had distal osteolysis. Close fit cementless stem in coronal and saggital planes without having distal stem fixation were proved to have an excellent mechanical fixation and provided favorable mechanical loading. Close fit in the proximal canal with a circumferential porous coating reduced the incidence of osteolysis. Factors contributing to good results in this young patient group are improved design of the prosthesis, improved surgical technique, strong trabecular bone and the use of smaller femoral head and thick polys. Although there was no aseptic loosening of the hip, high incidence of linear and volumetric wear of polyethylene liner in these young patients remains to be a challenging problem.