Swan neck-deformity

2. Swan Neck Deformity

6. Swan neck deformity. The volar plate is torn, causing the joint to
open abnormally under the pull of the extensor ligaments.

7. Swan-Neck Deformity
•Typically defined as:
– proximal interphalangeal (PIP) joint
hyperextension
–with concurrent distal interphalangeal (DIP)
joint flexion
•Not necessarily unique to RA but rather an
end result of muscle and tendon
imbalance caused by RA.

9. Swan-Neck Deformity
•Not necessarily unique to RA but rather an
end result of muscle and tendon
imbalance caused by RA

10. Nalebuff Classification
1989
•Type I - PIP joints flexible in all positions
–No intrinsic tightness or functional loss
•Type II - PIP joint flexion limited in certain positions
–Intrinsic tightness
–Limited PIP motion with extended MCP with ulnar deviation
•Type III - PIP joint flexion limited in all positions
–Near normal radiograph
•Type IV - PIP joints stiff with poor radiographic
appearance

11. Pathophysiology
•The intercalated joint collapse concept of
Landsmeer means that collapse of a joint
in one direction will result in deformity of
the next distal joint in the opposite
direction.
–Z deformity

14. Pathophysiology
•In a normal finger, intrinsic muscles serve
as:
–flexors of the MCP joint
–extensors of the PIP and DIP joints
•By being located volar to the MCP joint
axis and dorsal to the PIP and DIP joint
axes

15. Pathophysiology
•Intrinsic tightness increases the flexor pull on the
MCP joint and hyperextension of PIPJ
• Weak flexor power aggravates this by being
unable to pull the middle phalanx.
–DIPJ and MCPJ hyperextension follows
•Constant efforts to extend the finger against this
pull then leads to stretching of the collateral
ligaments and weakening of the volar plate at
the PIPJ.

16. Pathophysiology
•the lateral bands are constrained in their dorsal
position with the extensor apparatus migrating
proximally
–therefore upsetting the flexor-extensor balance,
•The lateral bands in this position act to increase
the pull of the central slip that attaches to the
dorsal base of the middle phalanx.
–Leading to hyperextension of PIPJ

17. Pathophysiology
•The increase of FPL tension resulting from
hyperextension of the PIP joint leads to a
reciprocal flexion of the DIP joint.
•DIP mallet deformity also from:
–Joint erosion
–Extensor tendon attentuation or rupture
•Progressive disease leads to joint
destruction and fixed contracture.

18. Hashemi-Nejad and Goddard (1994)
-multidisciplinary approach is best
-an affected joint will affect other joints
-early synovectomy is worthwhile after a 6-month trial of
non-operative treatment
-tenosynovectomy decreases the risk of tendon rupture,
-the wrist is the key in the RA hand
-the thumb is a very important source of disability
-silastic MCPJ arthroplasty is successful in reducing pain
and improving function

19. Feldon (1993) lists the aims of
surgery in the RA hand:
1. pain relief
2. functional improvement
3. preventing disease progression
4. cosmetic improvement
Note that the presence of a painless
deformity with minimal function deficit is
not an indication for surgery.

20. Management
•Millender and Nalebuff staging system
(1975) is a good guideline for identifying
treatment options in RA

22. Principles
•Prevention
•Correct PIPJ hyperextension
•Restore DIPJ extension

23. Type1

–Silver ring splint to flex PIPJ
–Volar dermatodesis
–Correction of any MCPJ abnormality first
–Flexor tenosynovectomy (if synovitis is present)
–Flexor tenodesis - FDS slip through A2 pulley then
looped back to itself
–Retinacular ligament reconstruction
–Release ulnar lateral band proximally and pass volar
to PIPJ axis ® sheath

24. Silver Ring Splint
•Permit active PIP
flexion and limit
hyperextension of the
PIP joint
•

27. DIP Fusion
•Difficult and unreliable to restore the
extensor apparatus at DIP level cause
underlying RA disease will destroy the
repair
•Also secondary arthritis within DIP may
make attempts to mobilise joint unwise
•

30. Dermadesis
•Used to prevent PIP hyperextension bu
creating a skin shortage volarly
•Elliptical skin wedge (4-5mm at widest) is
removed from volar aspect of PIP
•Care not too disturb venous drainage or
violate the flexor sheath
•Skin closed with PIP in flexion
•Only useful if done in conjunction with
other procedures ie DIP fusion

31. Flexor Tendon Tenodesis
“sublimis sling”
•Used as checkrein against hyperextension ie
restoration of strong volar support
•One slip of FDS is divided ~1.5cm proximal to
PIP
•This is then separated from its corresponding
slip bit left attached distally
•With joint at 20-30 degrees the detached slip is
fixed proximally
–Anchored to thickened margin of sheath, distal edge
of A2 or Mitek
•Nalebuff did simpler procedure whereby he
passed split tendon around A1 pulley

33. Reticular Ligament
Reconstruction
•Credited to Littler
•Ulnar lateral band is freed from extensor
mechanism proximally but left attached distally
•Passed volar to Cleland’s fibres to bring it volar
to axis of PIP
•Band is sutured to the fibrous tendon sheath
under enough tension to restore DIP extension
and prevent hyperextension at PIP
•However, in RA may have destruction of
terminal tendon so no amount of tension applied
to the relocated tendon will achieve DIP
extension

34. Type 2
•Looks like Type 1 but PIP movement is limited in
certain positions related to position of MCPJ
–MCPJ extended/radial deviation then limited passive
PIP ROM
–MCPJ flexed/ulnar deviated then PIP ROM increased
•As MCPJ subluxates and the intrinsics get tight
a secondary swan neck develops as a result of
muscular imbalance
•Not sufficient to restrict PIPJ hyperextension,
intrinsics must be released plus MCPJ
subluxation must be corrected +/- arthroplasty

35. Intrinsic Release
•Photo on camera
• A rhomboid portion of the ulnar extensor
aponeurosis is then resected
•This procedure resects the lateral band
through which the abnormally tight
intrinsics have caused MP flexion and PIP
hyperextension

36. Type 3
• unlike type 1 & 2 have significant functional
disability due to inability to grasp objects
•Not joint destruction but restriction due to:
–Extensor mechanism
–Collateral ligaments
–Skin
•First goal is to restore passive ROM
–PIPJ manipulation
–Skin release
–Lateral band mobilisation
–Then correction of deformity after motion restored

37. PIPJ Manipulation
•MUA possible up to 80-90 degrees
•Usually in conjunction with intrinsic
release, arthroplasty or tenosynovectomy

38. Skin Release
•Dorsal skin may limit the amount of
passive flexion that is achieved during
manipulation
•Tension minimised with an oblique incision
just distal to the PIPJ
–Allowing skin edges to spread
–Closes 2-3 weeks by secondary intention
–PHOTO 2112

39. Lateral Band Mobilisation
•Lateral bands are displaced dorsally
•Free lateral bands from central slip using 2
parallel incisions allows flexion without
releasing lateral bands or lengthening
central slip
•PHOTO 2113

40. Type 4
•Patients with stiff PIPJ and radiographic
evidence of advanced intra-articular
changes require salvage procedure
–Fusion or arthroplasty
•PHOTO 2114