Different types of highly cross-linked polyethylene (HXLPE) have been introduced widely in acetabular cups in hip prostheses to reduce the incidence of wear debris-induced osteolysis. Also, we reported that HXLPE cups with 28-mm
Aseptic loosening induced by wear debris of polyethylene (PE) is the most common cause of long-term total hip arthroplasty failure. In the previous studies, we reported that the protruding contour and surface morphology of metallic femoral head brought an increase of PE wear. Alumina ceramics is advantageous (neutral shape and smooth surface) for precision machining compared with metal materials, because hardness of ceramics is higher than that of metal materials. In this study, we measured the roundness and the roughness of retrieved
Trabecular materials show great promise for soft-tissue attachment to prosthetic implants. Results with Tantalum have been very encouraging, however, it remains unclear if this in-growth is secondary to the specific metal or its generic structure,. If structure, is there a specific tolerance with respect to porosity and pore size? In a canine model, bulk blocks of porous
We report the results of our continued review of 11 total hip arthroplasties using 22.225 mm
In total hip arthroplasty (THA), one of concerned issues is osteolysis due to wear debris of ultra-high molecular weight polyethylene (PE) which often leads to aseptic loosening. Reduction of PE wear debris is essential to prevent osteolysis, and different bearing combination as well as improvement of the bearing material itself have been attempted. Hence alumina ceramics was introduced for THA, aiming to reduce PE wear debris. Ceramic on PE couple showed good results in clinical wear compared with metal on PE couples. Highly cross-linked PE (HXLPE) with gamma-ray or electron-beam irradiation followed by thermal treatment has also demonstrated a remarkably low wear in the previous in vitro studies. In in vivo studies, the wear of HXLPE acetabular cups against
Aim:
Introduction and Aims: Recently, concerns have emerged regarding the high stiffness of acetabular components inserted with
Wear simulator studies suggest low wear rates of
Introduction. Cross linked polyethylene (XLPE) has gained popularity as a bearing surface of choice for younger patients despite only medium term results being available for wear rates. Concern remains regarding the long-term stability and durability of these materials. In order to address these issues we present the longest radiological and clinical follow-up of XLPE. Patients/Materials & Methods. Since 1986, we have prospectively studied a group of 17 patients (19 hips) that underwent a cemented Charnley low friction arthroplasty using a combination of 22.225mm
A consensus on total hip arthroplasty (THA) concluded that the major remaining issues of concern included the long-term fixation of the joint replacement, osteolysis due to poluethylene (PE) wear debris which often leads to aseptic loosening. Alumina ceramics had been extensively used in medicine, and we started using the
The study was designed to compare the clinical performance of an
We report the results of our continued review of 14 hip arthroplasties using
A retrospective study was performed to evaluate the safety and effectiveness of an alumina-based total knee arthroplasty system (Low Friction Anatomical, LFA, Kyocera, Kyoto, Japan). The system, which uses modern materials and contemporary component design, has been in clinical use in Japan since 1992. The system uses an alumina femoral component that articulates against standard polyethylene tibial and patellar components. The retrospective study evaluated the clinical performance of amodern-style ceramic femoral component and included 60 knees (49 patients) with an average follow-up of 3.8 years. Clinical outcomes were assessed by the Japanese Orthopaedic Association (JOA) Knee Rating Scale, which is comparable to the Knee Society Rating Scale used in the United States. Radiographic outcomes were assessed by the operating surgeon and another independent reviewer. The radiographs were reviewed for the presence or absence of lytic lines, implant and anatomical alignment, and other pertinent radiographic findings. Complications during the follow-up period were noted. Total knee replacement with the LFA system improved JOA scores in 98% of the cases. Mechanical and prosthetic alignment were satisfactory for all knees. The following results were noted:. No fractures or failures associated with the
We have been using a Charnley type hip prosthesis with an
Introduction. Wear of the ultra high molecular weight polyethylene (UHMWPE) cup and the resulting loosening has been shown to limit the long-term results of the Charnley low-frictional torque arthroplasty (LFA). Factors affecting wear rates have been studied: level of patient activity, effective roughness of the stainless steel head, impingement and the possible variations in wear characteristics of UHMWPE. Since patients' activity level cannot be predicted or modified, alternative materials were examined. Methods and Results. The Charnley 22.225 mm diameter head of
Alumina ceramic-ceramic bearings have the benefit of very low wear and studies showing the complete absence of osteolysis during the first decade of close study. However, good results depend on several critical factors including surgical exposure, surgical technique, component placement, and choice of component design. The following abstract discusses our experience with several of these factors. Initially, there were concerns that the use of ceramic-ceramic bearings would lead to a higher incidence of hip dislocation since the bearings have fewer femoral head-length choices and the absence of lipped-liners. In our prospective study of 418 hips the incidence of hip dislocation at 1 to 10 year followup is 0.5% (2/418). This experience suggests that the use of alumina ceramic-ceramic bearings is not associated with an increased incidence of dislocation. More recently, concerns about squeaking of alumina ceramic-ceramic bearings have been reported, particularly from centers in the United States. To investigate this issue, we reviewed information on 1275 consecutive revision THAs and 1039 consecutive primary ceramic-ceramic THA that had been performed at two institutions between 1996 and 2007. To identify the influence of the implant design on the incidence of squeaking we divided the primary hips into three groups with group 1: flush mounted ceramic liner; group 2a: recessed ceramic liner mated with a stem made of TiAlV; and group 2b: recessed ceramic liner mated with a stem made of a beta titanium alloy comprised of 12% molybdenum, 6% Zirconium, and 2% Iron. Analysis of the 1275 revision hips revealed 5 alumina ceramic-ceramic hips in patients who complained of squeaking or grinding. All 5 hips were designs that included a ceramic liner that was recessed inside of an elevated metal rim. All 5 hips also demonstrated metallosis at the time of revision. In primary THA, Group 2b had statistically significantly more squeaking (9 of 118) than group 2a (10 of 321) which had statistically significantly more squeaking than group 1 (6 of 700). In addition, the severity of squeaking between the groups was qualitatively different. Patients in Group 2b who complained of squeaking would often experience squeaking frequently throughout the day and could be demonstrated in the physician’s office. By contrast, patients in Group 1 who noted squeaking stated that the hip squeaked once a day to once a year. No patient in Group 1 complained of frequent squeaking or could demonstrate squeaking in the physicians’ office. Further, joint fluid analysis from a patient in Group 2b who complained of squeaking revealed metal from both the femoral (Molybdenum) and acetabular (Aluminum) components. As reported in another abstract at this meeting, 10 year survivorship of flush-mounted alumina ceramic-ceramic THA is 98.4% (95% confidence interval 97.1–100%) and no patient in that prospective clinical studies demonstrated radiographic evidence of osteolysis or wear. These experiences demonstrate that THA using alumina ceramic-ceramic is extremely reliable with low revision and dislocation rates and an absence of osteolysis. Significant squeaking is not associated with flush-mounted
We report the results of our continued review of 11 hip arthroplasties using 22.225mm
Hypersensitivity to metal alloy orthopaedic implants has become identified increasingly as a cause of implant failure. Because of their hypoallergenic properties, ceramic materials have been recommended as an alternative to metals. Unfortunately, the cost of ceramics and limitations imposed by their material properties has restricted these applications. The metalloceramic composite Oxinium® has been suggested as asubstitute. This is the first study to prospectively compare these materials in patients with documented cobalt-chrome hypersensitivity. Over a period of ten years, preoperative screening using skin patch testing and in vitro leukocyte stimulation testing of patients with gonarthrosis and a history of metal hypersensitivity identified sixteen patients with allergy to cobalt-chrome alloy. Twelve (all&
) underwent primary, and four underwent revision (3&
, 1%) knee replacement surgery using either
Ultra high molecular weight polyethylene (UHMWPE) was introduced into clinical practice by Charnley in November 1962 and has remained the standard material for the hip and other total joint arthroplasties. Wear of the UHMWPE cup, although studied from the beginning, did not appear to be a clinical problem although Charnley suspected that this would be so in the long term. A review of the outcome of the Charnley low-friction arthroplasty in patients under the age of 40 years at the time of the operation has shown that the incidence of cup migration was exponentially related to the depth of cup penetration. A prospective study using 22.225 mm
Introduction. Total elbow arthroplasty (TEA) is a widely accepted for the treatment for damaged rheumatoid elbows to achieve sufficient joint function. The current prospective study reports the long term follow-up of TEA with an unlinked stem type (Stemmed Kyocera type I, SKC-I) with a solid trochlea on patients who have rheumatoid arthritis (RA). SKC-1 is derived from an unlinked surface replacement prosthesis using polycrystalline alumina ceramics on high-density polyethylene (Kyocera type I), which was developed in 1979, based on the measurement study on the cadaveric elbows. Materials and Methods. 57 elbows (Larsen’s grade IV and V) from 45 RA patients replaced by SKC-1 were investigated. Cement fixation was used in all cases. The duration of follow-up ranged from 36 to 154 (average 73. 7) months. The clinical condition of each elbow before and after operation was assessed according to the scoring system of Japanese Orthopaedic Association (JOA) elbow scoring system (maximum 100 points), which is composed of scores for pain, activity of daily life, muscle strength, range of motion, instability, and deformity of the joint. On the basis of this system, the results are defined as excellent (90–100 points), good (75–89), fair (60–74), and poor (<
60). Radiographic loosening was defined as a progressive radiolucent line of more than two millimeters that completely surrounded the prosthesis. Results. The average postoperative JOA score improved from 43. 5±10. 2. °. to 81. 0±}10. 3. °. , with marked pain relief. The mean range of motion (ROM) of extension/flexion before the surgery was –35. 7±}22. 4/117. 1±}19. 1. °. and at last follow-up was −17 5±}12. 7/136. 3±}11. 4. °. The mean ROM of pronation /supination improved from 51. 1±}23. 4/56. 5±}28. 5. °. to 78. 3±}16. 8/82. 3±}16. 5. °. Of the 57 elbows, 9 elbows were judged to have excellent results, 37 had good results, 8 had fair results, and 3 had poor results. There were no instances of ulnar nerve palsy, triceps avulsion, or postoperative infection. Medial or lateral epicondylar fracture occurred in 2 cases during the operation, and union was achieved 3 months later. Massive instability with joint dislocation was seen in 3 cases of mutilans arthritis, resulting in poor results. Aseptic loosening was seen in 3 elbows. Revision surgery was performed in 1 case of accidental post-operative distal humerus fracture, and in another of olecranon fracture with the breakage of the ulnar component. With loosening defined as the end point, Kaplan-Meier curve of the cumulative probability of survivorship demonstrates the likelihood of survival of the prosthesis at 93. 8 percent for as long as 10 years. Discussion. The results of the current study showed a high reliability of the SKC-1 prosthesis with the novel