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Biomedical subjects

A B Swanson

Publications and source records attributed to A B Swanson.

At least 19 recordsLinked to original sources
PubMed1997

Use of grommets for flexible hinge implant arthroplasty of the great toe.

A double stemmed flexible hinge implant was designed in 1974 for use with the Mayo type resection arthroplasty of the first metatarsophalangeal joint. Press-fit titanium grommets were developed in 1985 to protect the implant midsection from sharp bony edges and shearing forces that can lead to implant abrasion or fracture, and particulate synovitis. The study of 90 first metatarsophalangeal joint implant arthroplasties performed with encircling press fit titanium grommets showed favorable bone response around the implant stems and the bone to grommet interface, with absence of complications relating to particulate reactivity, implant or grommet fracture. These findings suggest that the grommets effectively protect the implant to bone interface, improve implant durability, and prevent particulate synovitis.

Adult↗
PubMed1997

Use of grommets for flexible implant resection arthroplasty of the metacarpophalangeal joint.

In 1987, after 11 years of research, press fit titanium circumferential grommets were introduced for arthroplasty of the metacarpophalangeal joint to protect the flexible hinge implant midsection from sharp bony edges and shearing forces that can initiate implant abrasions and tears leading to implant fracture and formation of silicone wear particles. The effectiveness of the titanium circumferential grommets was assessed by comparing the results of 170 metacarpophalangeal joint implant (high performance) arthroplasties performed with (139 joints) and without (31 joints) grommets in 38 patients presenting an average 5.8 years followup. Both groups obtained pain relief, functional motion, stability, and correction of deformity. There was no evidence of particulate synovitis or infection. There were four implant fractures (12.9%) in the nongrommet group, and one (0.7%), because of implant rotation, in the grommet group. Although favorable bone remodeling was observed in both groups, the grommet group showed greater bone preservation at the metaphyseal and midshaft levels and increased intramedullary bone production around the implant stems. The results depend on appropriate surgical staging, meticulous operative and postoperative techniques, severity and progression of disease, and implant durability. The circumferential grommets safely and effectively protect the implant to bone interface to further the durability of implant arthroplasty of the metacarpophalangeal joint.

Arthritis, Rheumatoid↗
PubMed1997

Carpal bone titanium implant arthroplasty. 10 years' experience.

In 1984, in an effort to address the silicone wear particle problem, titanium implants were developed for the scaphoid, lunate, and trapeziometacarpal joint. The design of these implants closely resembled their silicone counterparts, though some modifications were made to accommodate the properties of unalloyed titanium and enhance their stability. Carpal bone implants act as articulating spacers to help maintain the relationship of adjacent carpal bones after local resection procedures. Their use allows carpal stabilization procedures and provides functional mobility with good strength and pain relief. Their surgical application began in 1985. The 10-year clinical experience seems very promising to date.

Adult↗
PubMed1994

Adsorption of collagenase to particulate titanium: a possible mechanism for collagenase localization in periprosthetic tissue.

Osteolysis is a central feature of aseptic loosening of orthopaedic joint prostheses. This destructive process is believed to result from phagocytosis of implant wear debris by periprosthetic and synovial macrophages and the subsequent release of proinflammatory mediators, including collagenase. Isolated murine macrophages were cultured in vitro with particulate titanium in order to explore the mechanism of macrophage activation by particulate wear debris. The results, in which the amount of secreted, soluble collagenase in culture supernatants was inversely proportional to titanium concentration, suggested that titanium strongly adsorbed secreted collagenase. This inference was confirmed by direct binding assays in which particulate titanium coated with adsorbed collagenase bound an alkaline phosphatase conjugated anti-collagenase antibody, but not a conjugated anti-IgG antibody. Adsorption of collagenase was not influenced by preincubation of titanium particles with albumin. The adsorbed collagenase remained enzymatically active as indicated by its ability to hydrolyze a synthetic peptide substrate. These results demonstrate that particulate titanium stimulates collagenase production by macrophages and then strongly adsorbs the secreted proinflammatory enzyme. The process of macrophage stimulation, collagenase secretion, and adsorption may represent an important mechanism for localization and concentration of collagenase in periprosthetic and synovial tissue, a mechanism that ultimately triggers bone resorption through osteoclast activation.

Adsorption↗
PubMed1994

Hemorrhagic rupture of the shoulder.

Two cases of hemarthrosis and rupture of the shoulder joint are described and 6 reported cases are reviewed; 5 of these were associated with a destructive glenohumeral joint arthropathy and rotator cuff dissolution. All have occurred suddenly, without trauma, in elderly persons. Conservative treatment is often successful, but recurrent episodes of rupture may require replacement arthroplasty.

Aged↗
PubMed1994

Flexible implant resection arthroplasty of the proximal interphalangeal joint.

Flexible implant arthroplasty of the PIP joint in post-traumatic disorders can have very successful long-term results provided that the recommended surgical indications, operative techniques, and postoperative rehabilitation programs are carefully adhered to. Stability of the collateral ligament system and integrity of the extensor and flexor mechanism are essential prerequisites. A central slip splitting, central slip sparing, and palmar approach are described. The latter is preferred in post-traumatic conditions provided that the extensor mechanism is intact.

Finger Injuries↗
PubMed1993

Implant resection arthroplasty in the treatment of Kienböck's disease.

The lunate implant acts as an articulating spacer to maintain the carpal bones relationship after a resection procedure. Its use helps preserve functional wrist mobility and stability. Our experience spans 25 years and the use of three materials. Since 1986, we have used lunate implants made of unalloyed titanium with very promising results. This procedure requires strict surgical indications, an exacting technique, associated intercarpal bone fusions as indicated, and the avoidance of abusive activity.

Arthroplasty↗
PubMed1992

Femoral head intramedullary stemmed implant. A historical prospective.

A historical review reveals that McBride may have been the first to use a femoral head intramedullary stemmed hip implant. It had a threaded stem and limited use. Eicher may have been the first to develop and use the smooth intramedullary stemmed femoral implant with a calcar collar, which was the forerunner of implants used today. Moore subsequently developed the self-locking intramedullary stemmed femoral implant with a calcar collar. Shortly thereafter, Thompson introduced a similar prosthesis. These four surgeons pioneered the development of the intramedullary stemmed femoral head prosthesis, which has been a key contribution to modern hip reconstruction.

Femur Head↗
PubMed1991

Constrained total elbow arthroplasty.

In 1972, the senior author designed a condylar-sparing constrained hinge elbow prosthesis with a high-density polyethylene bushing. The condylar-sparing design allows both intercondylar and intramedullary fixation of the humeral component with methylmethacrylate cement. Reattachment of the muscles and collateral ligaments to the preserved condyles provides further stability. The clinical experience spans more than 16 years in 42 elbows with a relatively low loosening rate of 7%. The implant was removed and not replaced in three elbows: one for late infection, one for posttraumatic comminuted fracture of the distal humerus, and one for loosening of a humeral component. A series of 27 patients (31 elbows) with 24-204 months of follow-up study (average, 77 months) had excellent pain relief and an average range of motion of 129 degrees flexion, -44 degrees extension, 69 degrees pronation, and 61 degrees supination.

Bone Cements↗
PubMed1991

The use of a grommet bone liner for flexible hinge implant arthroplasty of the great toe.

Press-fit titanium grommets were developed to shield flexible hinged silicone implants used for arthroplasty of the radiocarpal, metacarpophalangeal, and metatarsophalangeal joints. Since 1985, 179 titanium circumferential grommets were used in 90 first metatarsophalangeal joints with excellent, pain-free, functional results and favorable bone response around the implant stems and at the bone-grommet interface. There were no complications due to particulate reactivity, implant fracture, or grommet fracture. The use of circumferential titanium grommets appears to be a safe and effective method to improve the long-term durability of flexible hinge implant arthroplasty of the first metatarsophalangeal joint.

Adult↗
PubMed1991

Flexible implant arthroplasty of the radiocarpal joint.

The radiocarpal, distal radioulnar, and intercarpal joints can be affected individually or in combination. Selection of the appropriate treatment method is based on accurate evaluation of the extent and severity of involvement. The durability of flexible implant resection arthroplasty of the radiocarpal joint has been further enhanced by the use of titanium grommets to protect the implant midsection, by secure dorsal and palmar capsuloligamentous reconstruction to restrict the mobility of 30 degrees flexion/30 degrees extension and 10 degrees ulnar/10 degrees radial deviation, by 6 weeks' postoperative immobilization, and by avoidance of abusive hand usage.

Humans↗