Flexor pollicis longus abductorplasty. A, Incision to radial side of thumb exposes insertion of flexor pollicis longus, interphalangeal joint, and base of proximal phalanx. Second curved incision to radial side of wrist exposes flexor pollicis longus near its musculotendinous juncture and permits tendon to be withdrawn from carpal canal. B, Flexor pollicis longus is transected at its insertion and withdrawn from carpal canal through wrist incision. It is passed subcutaneously to radial side of base of proximal phalanx. C to E, Interphalangeal joint of thumb is arthrodesed in about 15 degrees of flexion in adult. In child with open physis, distal joint may be tenodesed in about 15 degrees of flexion. F, Transfer of flexor pollicis longus to radial side of proximal phalanx reduces adduction-flexion deformity and augments thumb abduction by transferred position of flexor pollicis longus. Interphalangeal arthrodesis improves metacarpophalangeal joint extension by increasing lever arm of extensor pollicis longus on metacarpophalangeal joint. SEE TECHNIQUE 72.11.