Biomedical subjects

F C Ewald

Publications and source records attributed to F C Ewald.

58 records · Page 4Linked to original sources

PubMedDate not supplied

Total elbow arthroplasty.

In the eight-year experience at the authors' institution (1974-1981) with an unlinked resurfacing elbow prosthesis, one failure occurred due to loosening of an ulnar component (1 of 153; 0.6%). The authors concluded that loosening of the prosthetic components in bone is not a serious problem, but other problems remain. Postoperative dislocation continued after a lateral approach was adopted but improved with the use of components of variable sizes. Ulnar nerve palsies are an unsolved problem and require special investigation in the rheumatoid patient. Other soft tissue problems have been relieved by the more physiologic lateral approach. Indications have been expanded to include posttraumatic or osteoarthritic conditions in relatively inactive elderly patients.

Arthritis, Rheumatoid↗

PubMedDate not supplied

Hip cartilage supported by methacrylate in canine arthroplasty.

A theoretically attractive approach to femoral head arthroplasty would be the preservation of a"biologic" bearing surface composed of autogenous articular cartilage and subchondral bone, supported by a prosthetic material with mechanical properties similar to those of trabecular bone. The substitution of such a material for bone would preclude incomplete revascularization of the femoral head and eventual bony collapse. The advantages of preserving the patient's hip joint, even in the face of a fracture that has caused the loss of vascular supply to the femoral head, are self-evident. To test this hypothesis, seven dogs underwent hip arthroplasty, whereby the trabecular bone of the femoral head was replaced with polymethylmethacrylate. When killed 2 1/2 years after operation all of the dogs demonstrated injury or loss of articular cartilage in the superior aspect of the femoral head. The lesions are consistent with advanced osteoarthritis by gross and histologic examination. These lesions apparently were produced by changing either the geometry or stiffness, or both, of the material supporting the articular cartilage. Supporting human articular cartilage with methacrylate for joint arthroplasty is not recommended.

Animals↗

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↗