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Biomedical subjects

F F Buechel

Publications and source records attributed to F F Buechel.

27 records · Page 2Linked to original sources
PubMed1989

New Jersey low contact stress knee replacement system. Ten-year evaluation of meniscal bearings.

A metal-backed, interchangeable, meniscal bearing knee replacement system has been designed to combine low constraint forces with low contact stresses (LCS) to allow nearly normal joint articulation and loading as well as long-term wear resistance of the implants. System components allow unicompartmental, bicompartmental, tricompartmental, and revision knee arthroplasties. In this prospective comparison study, the early series of cases used methyl methacrylate for prosthesis-to-bone fixation, whereas the more recent series of knee replacements used sintered-bead porous coating to allow tissue ingrowth stabilization of all implants. Overall results in the first 149 cemented cases with 2- to 10-year follow-up (mean 7.6 years) were good to excellent in 85.2 per cent, fair in 3.4 per cent, and poor in 11.4 per cent using a strict knee scoring scale. Fair and poor results were seen predominantly in multiply operated and implant revision cases. The best cemented results were noted in primary cases, 95.1 per cent of which had good to excellent results. Overall results in the first 208 cementless cases with 2- to 7-year follow-up (mean 4.4 years) were good to excellent in 91.8 per cent, fair in 2.4 per cent, and poor in 5.8 per cent. Fair and poor results were also seen predominantly in multiply operated and implant revision cases. The best cementless results were noted in primary cases, 98.2 per cent of which had good to excellent results. Of 140 meniscal bearing implants in the entire series, one dislocation occurred (0.7 per cent) which required open bearing replacement. Of 217 rotating platform bearing implants in the entire series, 7 dislocations occurred (3.2 per cent), which required open bearing replacement or revision of components for malposition. These dislocations were seen predominantly in revision cases involving insufficient flexion stability; 6 of the 7 cases were revisions. This study demonstrates the efficacy of mobile bearing elements for use in knee replacement arthroplasty. It is essential that flexion and extension gaps be controlled to maintain contact pressure on such bearings to avoid problems of subluxation or dislocation.

Adult↗
PubMed1988

New Jersey low contact stress total ankle replacement: biomechanical rationale and review of 23 cementless cases.

A congruent contact, unconstrained, multiaxial ankle replacement has been developed for use without cement. A talar onlay component with a trochlear surface and central fixation fin uses a cylindrical articulating axis that reproduces the lateral talar curvature. A tibial inlay component with a 7 degree anteriorly inclined short fixation stem uses a flat loading plate, recessed anatomically into the distal tibia to distribute tibial loads to the ankle joint. For both components, made of cast cobalt-chromium-molybdenum, a 275-micron pore-size, sintered-bead, porous coating is used to allow tissue ingrowth stabilization. A congruent ultra-high molecular weight polyethylene bearing is inserted between the metallic implants. Its upper surface is flat, whereas its lower surface conforms to the trochlear surface, thereby providing unconstrained, sliding cylindrical motion with low contact stress on the bearing surfaces. Contact pressure and collateral ligaments maintain ankle stability during both static and dynamic loading conditions. Clinically, 23 total ankle arthroplasties were performed in 21 patients. The follow-up period ranged from 24 months to 64 months with a mean of 35.3 months. Diagnoses included rheumatoid arthritis, 6 patients (26.1%); osteoarthritis, 4 patients (17.4%); post-traumatic arthritis, 10 patients (43.5%); avascular necrosis of the talus, 2 patients (8.7%), and painful ankle fusion, 1 patient (4.3%). Pain was the primary reason for surgery in all cases. Postoperatively, 87% of ankles had no pain or, at most, mild pain. Postoperative complications included poor wound healing in four ankles, reflex sympathetic dystrophy in two ankles, deep infection in one ankle, and one bearing subluxation. No ankle replacements were removed and no fusions were performed for failed implants, although one bearing was exchanged without disrupting the metallic elements. In this report, the suggestion is made that total ankle arthroplasty may have an improved application in various arthritis disorders when used with biologic fixation and unconstrained mobile bearings.

Adult↗
PubMed1986

The New Jersey Low-Contact-Stress Knee Replacement System: biomechanical rationale and review of the first 123 cemented cases.

A mobile-bearing element, metal-backed, interchangeable knee replacement system has been designed to combine low constraint forces with low contact stresses (LCS), allowing nearly normal joint articulation and loading as well as long-term wear resistance of the implants. The system is versatile, including a large number of component options in variable sizes, and it may be used in both primary and revision arthroplasties. The overall results in the first 123 cemented cases (97 patients) with 2- to 7-year follow-up (average 3.7 years) were good to excellent in 88.6%, fair in 3.3%, and poor in 8.1%. Fair and poor results were seen predominantly in multiply operated and implant revision cases. The best results were noted in primary cases, 97.4% of which had good to excellent results. There have been no mechanical implant failures and no meniscal bearing dislocations in this series. Pain relief and restoration of function have been very gratifying with this system.

Adult↗
PubMed1985

Antibodies to synovial-derived cells in patients undergoing artificial prosthesis implants.

In this preliminary study, the authors have found cytotoxic complement-dependent synovial antibodies in the serum of patients undergoing prosthesis implantation; these were particularly evident in those patients undergoing revision surgery. In order to demonstrate the synovial antibodies, it was necessary that the authors modify the method they had previously used in their studies of cytotoxic lung and kidney antibodies. While conventional trypsinization dispersion produced synovial target cells that would not react in the test system, mechanical dispersion successfully produced target cells sensitive to complement-dependent cytotoxic antibodies. In this study, synovial antibodies reacted similarly to cells derived from the synovium of different individuals, but they did not react to cells derived from tissues other than synovium. This tissue specificity was confirmed by absorption studies that indicated the synovial antibodies to be organ specific. Whether these cytotoxic synovial antibodies can be predictive of the impending loss of an artificial prosthesis, or somehow be directly involved in the failure mechanism of that prosthesis, will require additional studies.

Absorption↗
PubMed1978

"Floating-socket" total shoulder replacement: anatomical, biomechanical, and surgical rationale.

A prosthesis based on a new concept of gleno-humeral motion has been developed and clinically tested for the past 2 years. The "floating-socket" total shoulder replacement contains a nondislocatable, dual spherical bearing system consisting of a small sphere within a larger sphere with their centers offset to provide the physiologic "floating fulcrum" for mechanically advantageous motion. This geometric configuration allows a prosthetic range of motion in excess of anatomical limits to allow soft tissue structures to limit motion rather than mechanical impingement. The device is constructed from Co--Cr--Mo alloy and RCH-1000 polyethylene such that no metal--metal contact can occur. Experimental results in a 112-lb adult male chimpanzee and six clinical cases have revealed superior fixation strength of both glenoid and humeral components, as well as functional adaptation of the prosthesis without fracture of fixturing bone or prosthetic dislocation.

Alloys↗
PubMed1977

Gleno-humeral joint in the chimpanzee: comparative anatomical analysis for use in endoprosthetic replacement.

The gleno-humeral joint of the adult chimpanzee is morphologically compared to the human shoulder to assess the feasibility of this animal for use in experimental prosthetic replacement. The anatomical structure appears similar enough to man to warrant investigation of this animal as a vehicle for experimental implant design in the shoulder. Several anatomical structural differences were noted which necessitated modification of the fixturing segments of a "Floating Socket" total gleno-humeral endoprosthesis.

Animals↗
PubMed1977

Shoulder replacement in the chimpanzee: surgical and post-operative management.

A modified "Floating-Socket" total shoulder replacement was implanted in an adult male chimpanzee using an anterior surgical approach. The surgical technique and the post-operative course are described. Clinical and X-ray follow-up for 17 months reveals satisfactory function of the implant with no apparent loosening of either glenoid or humeral components.

Animals↗
PubMedDate not supplied

Cylindrical total ankle joint replacement: surgical and biomechanical rationale.

Incongruent designs of total ankle arthroplasty are all unsatisfactory owing to inherently poor wear, deformation resistance, and poor stability. Several congruent designs are capable of providing good function. It is concluded that a cylindrical surface with a horizontal axis located at the center of curvature of the lateral border of the talar dome seems most desirable where adequate subtalar motion is present and a spherical type seems most desirable where such motion is not present. The "New Jersey" cylindrical total ankle arthroplasty using a cylindrical surface uses an ultrahigh molecular weight polyethylene talar component and a mortised cobalt-chromium alloy tibial component both stabilized with methylmethacrylate bone cement and dual fixation fins.

Ankle Joint↗