Examples from the Web for knee-length
There were rich, cozy-looking linens, used for knee-length skirts -- inspired, perhaps, by a sarong.
Ruffles adorned a cream-colored, knee-length linen skirt, giving it a funky edge.
There were sparkling hotpants, structured pajama tops, and knee-length fur coats (a collaboration with Philippe Beaulieu).Marc Jacob's Fall/Winter 2013 Show: Golden Pajama Party|Isabel Wilkinson|February 15, 2013|DAILY BEAST
Kate was wearing a £515 Stella McCartney knee-length dress, last worn to an opening at the National Portrait Gallery.
Tisci experimented with layering, mixing sheer, knee-length slips with fluted mini-skirts and cropped jackets.
Anthony—the oldest of the lot, in a knee-length tunic—turned to Gregory.Hunter Patrol|Henry Beam Piper and John J. McGuire
The lads of the party wear buckskin breeches of knee-length, and tan strapping over tan-colored stockings.Patriotic Plays and Pageants for Young People|Constance D'Arcy Mackay
The women's knee-length grass skirts were like the Melanesian, but the leader's was dyed a brilliant blue.West Of The Sun|Edgar Pangborn
The porter reappeared from his room wearing a pair of knee-length rubber boots.Lady Luck|Hugh Wiley
When tights were used they were completely concealed by a one-piece, knee-length bathing dress.Women's Bathing and Swimming Costume in the United States|Claudia B. Kidwell