Sticky Soles Of Feet, Burning Sensation In Legs. Hip Replacement Done. Causes?

hi my mum is 86 yrs old she has lately had to wear socks constantly even in bed as she said she has a feeling in the soles of her feet that she describes as if there were sticking plasters stuck to the bottom of her feet but turned sticky side down shes walking on the sticky side she had a hip replacement op last year would this have anything to do with it as she also has a burning sensation in her legs at night and cannot even cope with bedclothes on her only a light sheet any info would be great thank you.