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Biomedical subjects

F C Ewald

Publications and source records attributed to F C Ewald.

16 recordsLinked to original sources
PubMed1991

Early failure of silicone radial head implants in the rheumatoid elbow. A complication of silicone radial head implant arthroplasty.

Three cases of early recurrent synovitis of the rheumatoid elbow following silicone radial head implant arthroplasty are presented. All three patients underwent synovectomy with silicone radial head implant for pain and loss of function due to rheumatoid synovitis. All three implants failed within 4-9 months after surgery. This failure was associated with radiographic medial joint space widening. At reexploration, recurrent synovitis with hemosiderin pigmentation was noted. Patterns of prosthetic failure included fracture, fraying, and compressive deformation or rotary wear ("motar and pestle") of the silicone radial head; a prosthetic stem fracture was also present. Histologic examination of the synovium revealed evidence of silicone-induced synovitis; particulate, refractile silicone debris was associated with inflammatory and foreign body giant cells. The presence of rheumatoid destruction of the joint surface may have accelerated this process and may be a relative contraindication to silicone radial head implant arthroplasty.

Adult↗
PubMed1991

Radial head replacement in capitellocondylar total elbow arthroplasty. 2- to 6-year follow-up evaluation in rheumatoid arthritis.

We reviewed six capitellocondylar metal-to-plastic total elbow replacement prostheses with radial head components, implanted in patients with rheumatoid arthritis. At an average of 4.7 +/- 1.5 years, relief of pain, improvement of function, and a functional range of motion were preserved. Five of the six elbows (83%) were clinically rated good or excellent. Radiolucent lines were seen at the bone-cement interface in 50% of the humeral component stems and in all ulnar component boats within 2 years after surgery; none had progressed at subsequent examination. Most were less than or equal to 1 mm wide, and none were associated with clinical deterioration. Only one of the humeral components was radiographically loose. No radiolucent lines were seen along the stems of the ulnar or radial components. There were no postoperative dislocations when the radial component was used, presumably because the prosthetic radial head provided increased constraint. None of these elbows have required revision. Radial head replacement in capitellocondylar arthroplasty had been discontinued because radiolucent lines were observed at early review. However, the absence of clinical failure, dislocation, or progression of radiolucency at long-term follow-up examination favor radial head replacement in primary unconstrained total elbow arthroplasty.

Arthritis, Rheumatoid↗
PubMed1991

Unicompartmental versus total knee arthroplasty in the same patient. A comparative study.

The purpose of this study was to compare unicompartmental knee arthroplasty (UKA) with total knee arthroplasty (TKA) and more specifically to evaluate the role of the patella in patient preference between UKA and TKA. A group of 23 patients were chosen, each with a UKA in one knee and a TKA in the opposite knee. As a subset of the group, 13 patients were compared who had not had patellar resurfacing on their TKA side (Group A) versus ten patients who had patellar resurfacing (Group B). Each patient had a UKA and TKA performed during the same hospitalization. Each patient's resurfacing was performed by the same surgical team. Moreover, inpatient care and physical therapy for each patient's respective UKA and TKA were the same. Patient evaluation consisted of chart review, joint registry data, and telephone interviews that focused on patient preference regarding pain, stability, "feel," and ability to climb stairs. The 23 patients studied had an average follow-up period of 81 months (range, 38-153 months). There were 14 men and ten women with an average age of 67 years. Preoperative diagnosis was osteoarthritis in 22 patients and rheumatoid arthritis in one patient. Range of motion (ROM) improved from a preoperative mean of 106 degrees to 123 degrees postoperatively on the UKA side. Mean ROM for the Group A TKAs improved from 104 degrees to 109 degrees, whereas the Group B TKAs remained unchanged at 113 degrees. For patients surveyed in Group A, 31% stated that their UKA knee was their better knee overall, 15% stated that their TKA knee was their better knee overall, and 54% could find no difference.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

The Total Condylar III prosthesis in complex knee reconstruction.

Sixty-one Total Condylar III (TC III) prostheses were implanted in 59 patients at the authors' institution between March 1977 and December 1987. Among the knees with adequate clinical and roentgenographic data, the average follow-up period was 6.1 years. There were six primary arthroplasties and 29 revisions in this group. The primary diagnosis was osteoarthrosis in 17 patients, rheumatoid arthritis in 16 patients, and juvenile rheumatoid arthritis in two patients. The knee score improved from 21.9 preoperatively to 73.7 at last follow-up evaluation. Based on the knee score, there were 71% good or excellent results. There were three failures (8.6%). Radiolucent lines were present in at least one component in 71% of patients, but few of these were considered significant. Although rarely needed, the TC III prosthesis has been shown to be a satisfactory and durable solution to complex knee reconstructive problems including severe deformity, ligamentous instability, and bone loss.

Adult↗
PubMed1990

Uncemented press-fit total knee arthroplasty.

Nineteen total knee arthroplasties in 16 patients were performed using a new prosthesis designed specifically for uncemented, press-fit fixation without any provision for tissue ingrowth. This design may be suited for use in patients with juvenile rheumatoid arthritis, postseptic knees, failed total knee arthroplasties with large bone stock deficiencies, and young, active, overweight individuals. Preservation of bone stock is possible because the fixation stems are nails rather than larger cement pegs, removal for revision is easier without cement, sequestration of microbes within cement cannot occur, and bone graft may be continually loaded with this type of prosthesis. Pain relief, discarding crutch support, operative blood loss, and corrective alignment were equivalent to results obtained with cemented arthroplasty. Seventeen of the 18 knees available for review (average follow-up period, 3 years, 7 months; range of follow-up period, 2 years, 10 months to 4 years, 11 months) were pain-free. Range of motion averaged -2 degrees of extension to 101 degrees of flexion. Ambulation was unrestricted and unsupported in the majority of patients. Radiographic evaluation showed the development of increased bone density under the tibial plateau as well as a sclerotic line at the ends of the femoral and tibial stems. This observation gives support to the theory that multiple microtrabecular fractures with healing form a new supportive "subchondral bone plate." There was one incidence of tibial subsidence. Prosthesis migration and loosening were not observed.

Adult↗
PubMed1990

Bone loss in the distal anterior femur after total knee arthroplasty.

Bone loss in the distal anterior femur in asymptomatic total knee arthroplasty (TKA) patients has been noted roentgenographically and during revision surgery. A retrospective roentgenographic review of 147 TKA cases was carried out to document bone loss. The influence that the mode of fixation (porous coated and cemented) and the implant design have on bone loss was examined. The time of onset and the progression of bone loss were studied. Bone loss occurred in the distal anterior femur in the majority of cases reviewed (68%). The prevalence of bone loss was independent of the mode of fixation and the implant design. By qualitative observation, roentgenographically detectable bone loss occurred within the first postoperative year and did not progress further. Previously three-dimensional finite element analysis demonstrated that the replacement of the bearing surface of the femur with a stiff metallic implant reduces the stress in the distal anterior femur by at least one order of magnitude. It is therefore speculated that the observed bone loss results from stress shielding. The apparent lack of progression may reflect the development of a new remodeling equilibrium under the altered stress conditions. The bone loss in the distal anterior femur described has not been implicated as a source of failure. However, since the bone strength in the femoral region is compromised as it becomes osteopenic, bone failure may occur with longer periods of cyclic loading. Furthermore, as a result of bone loss, revision arthroplasty may be more difficult.

Aged↗
PubMed1990

Total knee arthroplasty with the kinematic prosthesis. Results after five to nine years: a follow-up note.

A review of the results of 192 kinematic total knee replacements five to nine years after the operation showed that the results were still satisfactory. At the time of the review, the ages of the patients ranged from twenty-two to eighty-seven years. About half of the patients had rheumatoid arthritis and the other half, osteoarthrosis. About 90 per cent of the results were rated good or excellent, and the average range of flexion was 109 degrees. Radiolucency was present around 40 per cent of the tibial components, 30 per cent of the femoral components, and 60 per cent of the patellar components, but the lines were thin and not progressive. The complications included loosening of the patellar components in five knees, one fracture of the tibial tray with loosening of the patellar component, one fracture of the patellar component, and one dislocation of the patellar component.

Adult↗
PubMed1978

Total hip replacement with and without osteotomy of the greater trochanter. Clinical and biomechanical comparisons in the same patients.

Twelve patients with bilateral hip replacement, one side performed with a trochanteric osteotomy and the other without osteotomy, were analyzed by review of the clinical records, the findings on physical examination, preoperative and postoperative Harris hip scores, each patient's evaluation, biomechanical analysis of the preoperative and postoperative roentgenograms of the hips and pelvis, and force-plate gait analysis. All operations yielded good results clinically but the majority of patients preferred the replacement done without osteotomy. Blood loss and trochanteric bursitis were greater problems in patients who had an osteotomy. There were no differences between the two groups in the postoperative Harris scores or in the biomechanical measurements made on the preoperative and postoperative roentgenograms except for the change in the abductor-muscle length. Changes in this parameter correlated well with the patients' symptoms and clinical findings.

Adult↗
PubMed1976

Complications of total hip-replacement arthorplasty in patients with rheumatoid arthritis.

During the period 1969 through 1974, 716 total hip-replacement arthorplasties were performed. The results of the surgery in 275 cases of rheumatoid arthritis as regards complications were compared with those in 382 procedures in cases of osteoarthritis. In contrast to the reports of others,the incidence of deep would infection in the two groups was found to be equal. Patients undergoing total hip-replacement arthroplasty as a revision of a previous operation had a substantially increased risk of infection. Patients with rheumatoid arthritis, however, were more subject to certain other complication (intraoperative fracture, difficulties with anesthesia, and malposition of prosthetic components), in addition to the complications that were predictable because of the involvement of multiple joints and the systemic disease process.

Adult↗
PubMedDate not supplied

Total knee arthroplasty experience at the Robert Breck Brigham Hospital.

Between 1973 and 1978, 1,474 metal-to-plastic knee arthroplasties were evaluated to determine the typical modes of failure and improved design concepts (Table 2). Although the concepts are still evolving, and longer follow-up is necessary, recent experience with nearly 1,000 semiconstrained devices allowing cruciate retention strongly suggests that duopatella and kinematic design concepts are correct. Soft tissue reconstruction is critical with these designs, since they rely heavily on soft tissue integrity and balance. If the concepts of soft tissue balance, prosthetic design, and physical rehabilitation are applied, total knee replacement is as reliable in relieving pain and restoring function as total hip replacement. The low incidence of radiolucency at the bone-cement interface (although the length of follow-up is relatively short), coupled with the results of in vitro bench testing, suggest that the longevity of this generation of knee implants should be adequate.

Biomechanical Phenomena↗
PubMedDate not supplied

Giant cell synovitis associated with failed polyethylene patellar replacements.

Destroyed patellar articular surfaces were replaced with a high molecular weight polyethylene prosthesis in two patients. The patellofemoral articulation of the femur consisted of eburnated bone in one case and degenerative cartilage in the other. Both operations failed within one year because of a giant cell synovitis caused by a high volume (0.2 cc) of fine polyethylene (1-100 mu) wear particles. Ultra high molecular weight polyethylene should not be used as a prosthetic bearing surface to articulate against cortical, cancellous or eburnated bone or against degenerative articular cartilage in a major joint.

Aged↗
PubMedDate not supplied

Comparison of preoperative, intraoperative and early postoperative total hip replacement with and without trochanteric osteotomy.

A series of 100 consecutive patients with total hip replacements in whom trochanteric osteotomy was performed was compared with 100 patients in whom the greater trochanter was left in place. The groups were comparable with respect to age and incidence of osteoarthritis and connective tissue disorders. Although no statistically significant difference was noted among trochanterectomy groups or disease subgroups in terms of preoperative impairment as indicated by preoperative Harris score, 16 patients presented exposure problems necessitating trochanteric osteotomy despite preoperative plans to leave the trochanter in place. Salvage operations after unsuccessful previous operations were performed in 18 patients in the osteotomy group and 11 in the nonosteotomy group. Mean operating time was 3 hours for patients in the osteotomy group and 2 hours for those in the nonosteotomy group. Considerably more intraoperative and postoperative blood replacement was required in the patients having osteotomy. Patients sat, stood, walked, and left the hospital sooner in the nonosteotomy group than in the osteotomy group. Trochanteric bursitis requiring treatment 3 or more months after operation occurred in 17 patients having osteotomy and in 3 patients not having osteotomy. Hematomas developed in 15 patients in the osteotomy group and in 4 in the nonosteotomy group. Ectopic bone formation was observed in 12 of the osteotomy group, 8 with limitation of function, and 5 of the nonosteotomy group; non had symptoms. Six osteotomized patients had troublesome abductor weakness secondary to wire breakage and proximal migration of the trochanter. The rates of infection and thrombophlebitis were low in both groups. When exposure was not difficult, leaving the trochanter intact had many advantages.

Collagen Diseases↗