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Biomedical subjects

A Wykman

Publications and source records attributed to A Wykman.

18 recordsLinked to original sources
PubMed1995

In vitro biocompatibility testing of polymers for orthopaedic implants using cultured fibroblasts and osteoblasts.

The biocompatibility of two polymers for potential use as orthopaedic implant materials in an isoelastic hip prosthesis was investigated. The interactions of polyetheretherketone (PEEK) and epoxy resin polymers (with and without carbon fibre reinforcement) with both fibroblasts and osteoblasts were tested using cell protein, intracellular reduced glutathione (GSH), leakage of lactate dehydrogenase and the MTT assay as indices of cellular cytotoxicity. The epoxy resin polymer was slightly cytotoxic to and inhibited the growth rate of fibroblasts (as assessed by total cell protein), and depleted GSH in both cell types. In contrast, the PEEK material did not display overt signs of cytotoxicity and, in fact, increased osteoblast cell protein content. This suggests that, of these two materials, PEEK would be the one of choice for development of an isoelastic implant and, in view of its stimulatory effect on osteoblast protein content, it may encourage ingrowth of bone around the prosthesis and thus minimize joint loosening.

3T3 Cells↗
PubMed1995

Hallux valgus in ballet dancers: a myth?

Among dancers it is widely believed that ballet dancing induces hallux valgus. Revision of radiographs of 63 active and 38 retired dancers of both sexes showed no increase in the valgus angulation of the hallux compared with that of nondancers.

Adolescent↗
PubMed1994

Biodegradable fixation of ankle fractures. A roentgen stereophotogrammetric study of 32 cases.

We performed a prospective randomized study comparing fixation with biodegradable polyglycolic acid (PGA) rods (n 15) or screws (n 17) in 32 selected displaced supination-eversion fractures. Immediate postoperative weight bearing in a walking cast was encouraged. An exact reconstruction of the ankle mortise was achieved in 26/32 ankles. Roentgen stereophotogrammetric analysis (RSA) revealed rather small movements in the ankle mortise during fracture healing. A better stability was achieved by using screws. After 6 months the clinical results did not differ. One case of sinus formation and one with local effusion occurred; both healed without impairing the clinical result. To compare the results with a nondegradable osteosynthesis technique, a reference group of supination-eversion fractures previously operated on with cerclage-wires, staples and pins was used. RSA showed better fracture stability with nondegradable fixation. The clinical results, however, did not differ.

Adult↗
PubMed1993

Ankle sprain and postural sway in basketball players.

The present study compares postural ankle stability between previously injured basketball players, uninjured players and a control/group. Postural sway was recorded and analysed by stabilometry using a specially designed computer-assisted forceplate. Recordings were obtained for 60 s on each foot. The stabilometric results in the players with no previous injuries did not differ from those in the controls. Players with a previously injured ankle differed significantly from the control group. These players had a larger mean postural sway and used a larger sway area.

Adolescent↗
PubMed1993

Spinal sagittal mobility and joint laxity in young ballet dancers. A comparative study between first-year students at the Swedish Ballet School and a control group.

The present study compares spinal configuration, spinal range of motion and joint mobility in first-year students of the Swedish Ballet School and in nondancing students of corresponding age and sex in a state school. The study comprises all the first-year (fourth grade) students (n = 23) at the Swedish Ballet School: 11 boys and 12 girls. Their dance practice time was 10 h per week. Thirty-six children in the fourth grade at a state school comprised the control group. None of the controls took ballet classes or participated in organised gymnastics out of school. The neutral spine configuration in standing and the sagittal spine mobility were measured using Debrunner's kyphometer and Myrin's inclinometer. Joint laxity was measured by employing a modified form of the Contompasis method. Compared with the controls, the dancers showed a higher incidence of joint hypermobility, greater mobility of the thoracic spine, a less prominent lordosis of the lumbar spine and a less prominent kyphosis in the thoracic spine in the neutral standing position. The dancers had done little or no ballet training before entering the ballet school at the age of ten. The results agree with those of earlier studies and suggest that increased flexibility is an asset for those being selected as future ballet dancers.

Child↗
PubMed1993

Knee motion after tibial osteotomy for arthrosis. Kinematic analysis of 7 patients.

The in vivo kinematics of the knee in 7 patients with moderate medial gonarthrosis was analyzed before and 6 months after high tibial osteotomy using roentgen stereophotogrammetric analysis. The inclination of the femorotibial helical axis of rotation did not change with knee flexion or after surgery. The femorotibial rotation increased after surgery. No consistent change in patellar position after surgery was found. Patella translated laterally as the knee was flexed with a maximum patellar translation of about 15 mm and rotated internally with a maximum patellar internal rotation of about 15 degrees. There was no significant change in patellar translation or rotation after surgery. There was a good concordance regarding the size of the tibial wedge removed during surgery, calculated from the Hip-Knee-Ankle radiographs and from the roentgen stereophotogrammetric measurements.

Aged↗
PubMed1992

Subsidence of porous coated noncemented femoral components in total hip arthroplasty. A roentgen stereophotogrammetric analysis.

Roentgen stereophotogrammetric analysis was used in the evaluation of subsidence in nine noncemented femoral components of the Biomet Taperloc prosthesis. After 2 years three components had subsided 0.7-0.9 mm. No distinct symptoms related to the micromotion appeared. The subsidence in this investigation was smaller than the reported subsidence of other noncemented prostheses.

Adult↗
PubMed1992

Walking ability after total hip replacement. A comparison of gait analysis in unilateral and bilateral cases.

We studied 50 patients before and after unilateral total hip replacement, and compared them, using gait analysis, with 22 having staged bilateral operations. The average age of the patients was 65 years at the first operation. The mean follow-up was 53 months for the unilateral cases and 27 months, after the second THR, for the bilateral cases. The average interval between first and second THR was 24 months. Patients with bilateral hip disease did not gain optimal function, even on the first side, until both hips had been replaced. Unilateral replacement gave better gait analysis results than did either side after bilateral procedures.

Bone Cements↗
PubMed1991

Total hip arthroplasty. A comparison between cemented and press-fit noncemented fixation.

This study compares cemented (Charnley) with noncemented (Honart Patel-Garches) total hip arthroplasty. 150 patients with osteoarthritis, rheumatoid arthritis, and miscellaneous conditions were randomized into either group with 75 in each. Patients were evaluated over 5 postoperative years with examinations at 6 months, at 1 year, and then annually. Each examination involved clinical assessment, objective gait analysis, and radiographic examination. The Charnley group improved faster than the HP-Garches group during the first 2 years. At the last evaluation the results were excellent or good in 79% in the Charnley group and 70% in the HP-Garches group. In the HP-Garches group midthigh pain occurred in 64%. Five patients with Charnley prostheses (6.7%) and 14 patients with HP-Garches prostheses (18.7% had revision surgery to correct mechanical loosening. Standard radiography revealed radiolucent zones in both groups, but this could not be related to the clinical outcome despite radiolucency being present in all noncemented replacements on the femoral side. Objective gait analysis confirmed inferior clinical results at 6 months in the HP-Garches group. There was no significant difference between the groups at the most recent evaluation. Our findings are not consistent with earlier optimistic expectations on press-fit noncemented total hip arthroplasties.

Aged↗
PubMed1989

Postural stability after total hip replacement.

Changes in postural stability were recorded before and after total hip replacement using a specially designed computer-assisted forceplate system. Twenty-one patients with unilateral osteoarthritis of the hip were randomised into two groups after operation with either a cemented Charnley or a non-cemented HP-Garches prosthesis. Postural stability was improved in both groups one year after operation and the sway pattern became normal.

Female↗
PubMed1987

Activation of cascade systems by hip arthroplasty. No difference between fixation with and without cement.

The acrylic bone cement has been regarded as a very potent activator of the hemostatic mechanisms. A battery of coagulation, fibrinolytic, and kallikrein variables were studied perioperatively in 21 patients undergoing hip arthroplasty with fixation of the prosthesis either with (Charnley) or without (HP-Garches) cement. Epidural analgesia was used and dextran 6 per cent as thromboprophylaxis. The HP-Garches procedure was shorter and caused less blood loss. No differences were found between the two surgical procedures regarding the activation of the cascade systems. The coagulation and fibrinolytic systems were activated early, but a week postoperatively the latter seems to predominate. A marked activation of the kallikrein system was apparent. Our study shows that despite thromboprophylaxis a marked activation of the coagulation, fibrinolytic, and kallikrein systems occurs in relation to hip arthroplasty irrespective of the use or nonuse of cement and irrespective of the volume of blood loss during surgery. It may be the reaming of the bone marrow that initiates the activation of the cascade systems.

Aged↗
PubMed1986

Total hip replacement. A comparison between cemented (Charnley) and non-cemented (HP Garches) fixation by clinical assessment and objective gait analysis.

In 119 patients with total hip replacement (THR) 61 were operated on with cemented (Charnley) and 58 with non-cemented (HP Garches) fixation. The assessment was performed by clinical examination and objective registration by gait analysis 6 and 12 months postoperatively. The group with cemented fixation (Charnley) demonstrated better results in all variables. The greatest difference between the groups was found at the 6 months' follow-up. The gait analysis was valuable in the assessment of locomotor function.

Aged↗
PubMedDate not supplied

Influence of acetabular component position in non-cemented total hip arthroplasty. A radiologic and clinical study.

Radiologic grading of non-cemented acetabular components in HP Garches total hip replacements was used to evaluate the relationship between a lack of supero-lateral cover of the acetabular component and clinical outcome. In 63 hips, three to five years after total hip arthroplasty, we observed that the acetabular component was partially uncovered in 56 per cent of cases. The fact that several components were partially uncovered did not influence the clinical outcome. Although the follow-up time is short the present study indicates that non-cemented HP Garches total hip arthroplasty is a technique which allows for stable fixation of the acetabular component.

Acetabulum↗