Ken Rudolph’s review published on Letterboxd :
Tanaquil Le Clercq (Tanny to most) was a prima ballerina, muse of George Balanchine (the love of her life whom she married) and Jerome Robbins - until she was struck down by paralyzing polio at age 27. Admittedly my knowledge of the ballet when I was young is non-existent, so I'm ashamed to admit that I had never heard of Le Clercq before this film.
The filmmakers had the advantage of plenty of performance kinescopes and films covering the active career of this unique talent...plus ample coverage with photos and interviews of the remainder of her life (she proved the doctors wrong and lived to age 80.) The film is even edited like a ballet: for example a striking montage of her dancing, whirling and collapsing made from sequences of varied dances which signaled her illness. The only reservation I had was that the film runs too long, runs out of steam in an effort to impose additional meaning to Le Clercq's life path after the illness.