Closed manipulative reduction has proved efficacious in a series of twenty-nine cases. In 80 per cent. of these cases, excellent or good functional results were obtained; in 8 per cent., the functional results were fair. Successful treatment by closed reduction depends upon:
1. Early institution of treatment.
2. Accomplishment of complete reduction.
3. Active treatment for a sufficiently long period.
The new curved cassette makes it possible to ascertain whether or not reduction has been accomplished.