Biomedical subjects
Publications and source records attributed to A Wykman.
Research suggests that hyperbaric oxygen therapy may have beneficial effects on ulcer healing and amputation rates in diabetic patients. This paper describes the design of a study that is evaluating its effects on chronic diabetic foot ulcers.
We performed a combined retro- and prospective study of injuries in a Swedish professional, classical ballet company during 5 consecutive years. There were 390 injuries incurred by 98 dancers over a 5-year period, i.e., 0.6 injuries/1000 dance hours. Most injuries were considered to be due to overuse. The median sick leave was 2.3 weeks per injury. The foot and ankle region is vulnerable in classical ballet dancers, and overuse injuries can result in long periods of sick leave. Of the dancers employed for more than 1 year 95% were suffered injuries during the study period. We found considerable differences in the injury profile between male and female and between younger and older dancers. Male dancers suffered more frequently from acute injuries to the knee joint. Traumatic injuries were seen most frequently in male soloists. Female dancers more often suffered overuse injuries, especially to the foot and ankle region. The younger dancers more often suffered traumatic injuries, for example, ankle sprain, and also stress fractures.
Explore the source record for details and available documents.
When studying the biocompatibility of orthopaedic biomaterials it is often necessary to discriminate between responses which show mild cytotoxicity. It is therefore essential to use a very sensitive index of toxicity. We have compared the sensitivity of four well-established indices of toxicity: total cell protein content, leakage of lactate dehydrogenase (LDH), reduced glutathione content and the MTT assay, with that of a novel index, alkaline phosphatase (ALP) activity. Comparisons were made by detecting nickel chloride toxicity in osteoblasts. ALP activity, the novel method, proved the most sensitive index of toxicity and it provides a convenient automated assay for assessing the interactions of materials with osteoblasts. The responses to nickel chloride and to aqueous extracts prepared from carbon fibre reinforced epoxy and polyetheretherketone (peek), two candidate materials for orthopaedic implants, were compared in primary and immortalized rat osteoblasts, and in primary human osteoblasts. Although the immortalized rat osteoblast cell line, FFC, was consistently the most sensitive cell type, the responses of the human cells and the FFC cell line were similar in terms of ALP activity throughout the range of nickel concentrations studied. Neither peek nor epoxy material extracts showed a significant decrease in the MTT or ALP responses in any of the three cell types. Our data suggest that immortalized rat osteoblasts may provide an in vitro model system for screening the biocompatibility of orthopaedic polymers.
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.
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.
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.
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.
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.
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.
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.
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.
Explore the source record for details and available documents.
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.
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.
Explore the source record for details and available documents.
Roentgen stereophotogrammetric analysis was used in the evaluation of subsidence in eight noncemented femoral components of the HP-Garches prosthesis. After 2 years, seven components had subsided 0.6-3.9 mm, i.e., more than observed in some cemented prostheses. No distinct symptoms related to the micromotion appeared.
Explore the source record for details and available documents.