Biomedical subjects

R G Wetherell

Publications and source records attributed to R G Wetherell.

5 recordsLinked to original sources

PubMed1992

The function of bipolar hip prostheses--a laboratory study using cadaveric acetabula.

Cadaveric acetabula were mounted in a hip simulator and the friction developed in each during articulation with a series of metal femoral head prostheses of differing sizes was measured. In a separate study, assembled Hastings bipolar hip prostheses were subjected to weight-bearing forces in the same acetabula and their self-righting mechanism was observed. The self-righting mechanism was found to function efficiently, in most cases overcoming the combined friction of the inner and outer articulations of the Hastings hip. However, during motion in the hip simulator a wide variation of friction was observed between different acetabula and within the same acetabulum with differing head size. In several cases this acetabular friction was found to be less than the friction in the inner articulation of the Hastings bipolar hip prosthesis, and this may explain some cases of reported failure of biarticular function.

Acetabulum↗

PubMed1990

The Hastings bipolar hemiarthroplasty for subcapital fractures of the femoral neck. A 10-year prospective study.

In a 10-year prospective study, 561 displaced subcapital fractures of the femoral neck in 546 patients were treated with the Hastings bipolar hemiarthroplasty. Within six months of their operations, 148 patients had died. In 322 hips followed up, 243 with adequate serial radiographs separated by more than one year, only 14 (5.6%) showed acetabular erosion. A group of 91 had been reviewed for between three and nine years (mean, 4 years 10 months) and of these, 95% had no pain or slight pain only. Comparison with an earlier series of conventional hemiarthroplasties reported from this institution showed that the clinical results were similar, but that the erosion rate had been halved.

Femoral Neck Fractures↗

PubMed1989

Flexor tendon repair: significant gain in strength from the Halsted peripheral suture technique.

A biomechanical study in vitro has evaluated a new modification of the core and peripheral suture technique for flexor tendon repair. Groups of repairs were conducted in cadaver tendons, using a core suture alone, a core suture with a simple running surface suture and a new modification involving a 'Halsted' horizontal mattress technique for the peripheral stitch. The Halsted modification increased the load at which a visible gap formed by 93%, the load at which a 2 mm gap formed by 77%, and the maximum strength by 89%. This increase was due to the technique; it did not depend on the suture material used. The bulk of the tendon repair was not significantly greater with the Halsted modification.

Biomechanical Phenomena↗

PubMed1989

The Hastings hip in osteoarthritis. A study of 47 cases with a 5-year follow-up period.

A prospective study of the use of the Hastings biarticular hemiarthroplasty for the treatment of osteoarthritis of the hip in 47 hips in elderly patients (mean age, 76 years), with a mean follow-up period of 5 years, is reported. Seventy-four percent of these patients were pain-free or had slight pain only. The results were best in patients older than 80 years. Survivorship analysis showed an 86.2% cumulative success rate at 7 years. Surgical complications occurred in only 4%. There were no deaths attributable to surgery. Acetabular erosion greater than 2 mm occurred in 22% but did not correlate with symptoms. This operation is useful in the management of elderly, unfit patients.

Aged↗

PubMed1989

Measurement of acetabular erosion. The effect of pelvic rotation on common landmarks.

Using dried bones which could be tilted and rotated, we assessed the accuracy of published radiographic methods for measuring the migration of prosthetic acetabular components and compared the results with a new method. The new line linking acetabular margins was significantly more accurate for proximal migration than the teardrop, the sacroiliac line or the sacroiliac-symphysis line. For medial migration, a new line tangential to the brim and through the horizontal mid-point of the obturator foramen was more accurate than Köhler's line, the ilio-ischial line or the iliopubic line. In combination, the two new lines can give a more accurate assessment of acetabular erosion than previous methods, since they are less affected by the differences in rotation commonly found in a series of radiographs.

Acetabulum↗