Biomedical subjects

S F Attfield

Publications and source records attributed to S F Attfield.

5 recordsLinked to original sources

PubMed2000

An evaluation of lycra garments in the lower limb using 3-D gait analysis and functional assessment (PEDI).

Whole body lycra garments were assessed in eight children using gait analysis, the paediatric evaluation of disability index (PEDI), and a questionnaire of parental acceptance. Seven of the children had cerebral palsy and one Duchennes muscular dystrophy. After initial assessment and fitting of the garment, there was a 2-week introduction period followed by 6 weeks of wearing the garment for at least 6 h everyday, following which they were re-assessed. The root mean square error (RMSE) was used as a measure of variability over three separate passes through the gait laboratory and was a reference figure for gait stability. Proximal stability around the pelvis improved for five children and distal stability improved for three. Five children improved in at least one aspect of the PEDI scale. Although the parents and children detected these improvements, they did not outweigh the disadvantages of wearing the suit and as a consequence only one out of eight families considered continuing with the lycra garment.

Cerebral Palsy↗

PubMed1996

Soft-tissue balance and recovery of proprioception after total knee replacement.

Decreasing proprioception of the knee is multifactorial and is a function of age and degenerative joint disease. Soft-tissue release during total knee replacement may have an influence. We have quantified soft-tissue imbalance at the time of knee replacement and attempted to eliminate it at full extension, using established methods. We studied the influence of residual soft-tissue imbalance on postoperative proprioception, assessing this in 38 patients before total knee replacement and at three and six months postoperatively. We found that proprioception improved in varus knees at three and six months after soft-tissue balancing procedures. Knees balanced in full extension and in flexion (< +/- 2 degrees) showed a significant improvement in proprioception (p < 0.0005) whereas those which were not balanced in flexion but fully balanced in extension had no significant improvement. We conclude that soft-tissue balance in both flexion and extension is important to allow satisfactory postoperative proprioception of the knee.

Arthritis↗

PubMed1995

An intramedullary aligned bone cutting jig for elbow replacement.

One of the main post operative complications of total elbow replacement has been dislocation and fracture of the olecranon. This has been associated with rotational malalignment of the bone cuts of the proximal ulna caused by the current free hand cutting method. This paper presents an intramedullary aligned bone cutting jig which gives rotational location on the ulna for the bone cuts, without notching the olecranon.

Biomedical Engineering↗

PubMed1994

Measurement of soft tissue imbalance in total knee arthroplasty using electronic instrumentation.

The existence of soft tissue contractures in arthritis and the presence of soft tissue imbalance at the time of a total knee arthroplasty causing deformity in the coronal plane has been debated extensively. This discussion was based on the use of instrumentation which tensed the medial and lateral soft tissues in an uncontrolled manner during the operation. Previous work by this research team has developed a surgical instrument to quantify soft tissue imbalance independently of the compressive passive loads through the knee. In order to validate this assumption, an electronic measuring system was developed to record the soft tissue imbalance at 0.25 mm distraction intervals of the knee. This soft-tissue measuring system consists of a surgical instrument containing electronic transducers, an analogue conditioning unit and a portable computer. The surgical instrument introduces a pivot to the centre of the knee in the coronal plane so that the clockwise and counterclockwise moments produced by the collateral soft tissues produce an angular deviation at the equilibrium position. Measurements of angular deviation and separation gap are recorded by the electronic transducers. Eight patients were measured whilst undergoing total knee replacement at Bretby Hall Orthopaedic Hospital. The mean change in angular deviation over an average distraction of the knee of 7.15 mm was 0.4 degrees with a standard deviation of 0.4. It is concluded that this is an acceptable error band for surgical measurement, and soft tissue imbalance can be defined as angular deviation independently of the passive compressive loads through the knee.

Anthropometry↗

PubMed1993

Quantification of soft-tissue imbalance in condylar knee arthroplasty.

Soft-tissue balance has been debated in recent publications in connection with the long-term survival of the 'condylar-type' knee prostheses. Present methods of assessment have all assumed that the soft tissues around the knee are inelastic strings. The authors have developed two instruments to quantify soft-tissue imbalance, at the time of the operation, with the assumption that the soft tissues are viscoelastic structures. These two soft-tissue balancing devices were consequently used on 121 patients undergoing condylar knee arthroplasties at the Derbyshire Royal Infirmary and Bretby Hall Orthopaedic Hospital. The first instrument consisted of two flat plates separated by four standard compression springs and provided a qualitative measure of imbalance assuming that the soft tissues were viscoelastic. It was used on 55 patients before being replaced by the quantitative measure of the second instrument. The authors have redefined soft-tissue imbalance, to take into account the viscoelastic nature of the soft tissues, as the resultant trapezoidal geometry of the knee after the bony cuts have been made and when the knee is tensed by equal forces both medially and laterally. The second balancer eliminates the requirement to quantify the individual tensions in the medial and lateral structures by introducing to the system a low-friction, central pivot in the coronal plane. Once the pivot is situated at the centre of the knee, an equilibrium position is achieved where the clockwise and counter-clockwise moments are equal. The tensions exerted by soft tissues can be assumed to be equal and opposite as their moment arms are the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Arthritis, Rheumatoid↗