ZF meaning in Medical ?

A walker or walking frame is a tool for disabled or frail people, who need additional support to maintain balance or stability while walking, most commonly due to age-related physical restrictions. In the United Kingdom, a common equivalent term for a walker is Zimmer frame, a genericised trademark from Zimmer Biomet, a major manufacturer of such devices and joint replacement parts.

Walkers started appearing in the early 1950s. The first US patent was awarded in 1953 to William Cribbes Robb, of Stretford, UK, for a device called "walking aid", which had been filed with the British patent office in August 1949. Two variants with wheels were both awarded US patents in May 1957, and the first non-wheeled design that was called a "walker" was patented in 1965 by Elmer F. Ries of Cincinnati, Ohio. The first walker to resemble modern walkers was patented in 1970 by Alfred A. Smith of Van Nuys, California.