This document discusses swan neck deformity, which begins as a mallet deformity from extensor tendon disruption in the distal finger joint, causing overpull of the central slip and hyperextension of the proximal interphalangeal joint. This tightens the lateral bands and central tendon in a fixed dorsal position, preventing sliding over the condyles during flexion. There are three types of swan neck deformities - type I is flexible, type II requires intrinsic release in addition to procedures like dermodesis or tendon reconstruction due to intrinsic muscle tightness, and type III deformities are stiff and may require joint manipulation and skin/band mobilization even without significant joint destruction.

1. SWAN NECK DEFORMITY
dr.mr.sadeghi
Tehran university of medical science

2. deformity may begin as a mallet deformity associated
with extensor tendon disruption at the distal joint with
secondary overpull of the central slip, causing
secondary proximal inter phalangeal joint
hyperextension

4. PIP
tightening of the lateral bands and central tendon, and
eventual adherence of the lateral bands in a fixed dorsal
position
so they can no longer slide over the condyles when the
proximal inter phalangeal joint is flexed

5. Nalebu , Feldon, and Millender :

6. Type I deformities are flexible
1. deromodesis,
2. extensor tenodesis of the proximal
interphalangeal joint,
3.fusion of the distal interphalangeal joint,
4.reconstruction of the retinacular ligament

7. Type II deformities intrinsic muscle tightness
require intrinsic release in addition to one

8. Type III deformities
stiff and do not allow satisfactory flexion
not have significant joint destruction radiographically.
joint manipulation, mobilization of the lateral bands, and
dorsal skin release.