guidebook. - Fanconi Anemia Research Fund

114
Fanconi Anemia: Guidelines for Diagnosis and Management
structures and facilitate carpal reduction.
After the carpus is placed on the end of the ulna, the
soft tissues are balanced by tightening of the capsule
and by a tendon transfer to redirect the deviating forces.
The wrist is held in position by a Kirschner wire. An
ulnar bow greater than 30 degrees requires a concomitant
wedge osteotomy at the apex of the deformity to
correct the angulation. The Kirschner wire is removed
eight to twelve weeks after surgery. A splint is made
and removed for exercises, with gradual weaning from
the splint. A nighttime splint regimen is encouraged
until skeletal maturity.
Numerous technical modifications have been proposed
to maintain alignment of the wrist position (Figure 12).
These include over-correction of the carpus, additional
tendon transfer, and prolonged Kirschner wire fixation.
Even microvascular free toe transfer to support
the radial side of the wrist with a growing part has been
advocated. The toe proximal phalanx is fused to the
base of the second metacarpal and the proximal metatarsal
affixed to the side of the distal ulna.
Unfortunately, no method reliably and permanently corrects
the radial deviation, balances the wrist, and allows
continued growth of the forearm. Currently, the maintenance
of the carpus on the end of the ulna without
sacrificing wrist mobility or stunting forearm growth
remains a daunting task. Recurrence after centralization
is the most common source of failure, and the cause
appears multifactorial. Operative causes include the
inability to obtain complete correction at surgery, inadequate
radial soft tissue release, and failure to balance
the radial force. Postoperative reasons consist of premature
Kirschner wire removal, poor postoperative splint
use, and the natural tendency for the shortened forearm