for pollicization of the index finger in child with hypoplastic thumb we require.. stable 1st carpo-carpal joint

for pollicization of the index finger in child with hypoplastic thumb we require:
a. stable 1st carpo-carpal joint
b.stable 2nd charpo-phalyngeal joint
c. functioning interphalyngeal joint of the index finger
d. good thenar ms.
(a) ??