SOLVED. Entangled by Paul Jason. Mystery about evil sister with bad leg who terrorizes good sister. [s]

[Bren fall in love with the sea.]

So this was about a lady who has a sister. the sister has a bad leg and is envious of the good sister and sets out to ruin her life. I think one of the sisters was Laura or Laurie. The end goal for the evil sister is that she wants a doctor to perform a surgery and switch her leg with the sister's. Yes, this would be considered a thriller.

SPOILER:

Bad sister kidnaps good sister but good sister is saved in the end. Came out late 70's or early 80's.

[Bren fall in love with the sea.]

This is still unsolved.

[Kris]

Please keep in mind the bump period is 30+ days for this large group, unless you have new information which can be added any time.

[Bren fall in love with the sea.]

Oh I am sorry..didn't realize.

[Kris]

No worries. We realize different groups have different rules. This group is quite large.

[Ayshe]

Entangled by Paul Jason maybe?
I found fragment in 1982 Kirkus reviews, which might be about it:
and tracks down the shady doctor (the notorious 1950s "guinea pig surgeon") who was last seen with the corpse (?) of Diana's mutilated twin baby-sister. Meanwhile, of course, that very doctor (now an East Village veterinarian) is, together with his monster/concubine Laurie, stalking Diana. And eventually Diana will indeed wind up in the mad-doctor's chamber of horrors-praying that someone rescues her before the Doc gives Laurie the second leg she's always wanted. . . by transplanting it from Diana. Occasionally silly-gross and far from original (think of Brian da Palma's Sisters, among others), but fans of popcorn-horror will find this fast, unpretentious fun -with a few spots of surprisingly bright dialogue

[Bren fall in love with the sea.]

That's it. Wow. I was just going to bump this thread up since it had been awhile. Thanks for finding it.