Finger deformities - Yusuf Bharmal

1. Finger
Deformities
Yusuf Bharmal

2. Finger extensor mechanism anatomy
Lateral view Dorsal view
DIP = distal interphalangeal
joint MCP =
metacarpophalangeal joint ORL
= oblique retinacular
ligament PIP = proximal
interphalangeal joint
TRL = transverse retinacular
ligament.

3. Anatomy
• The extrinsic extensor tendon:
– Originates in the forearm.
– Courses over the MCP joint.
– Has an indirect attachment
to the proximal phalanx.
• The primary extensor force
across the MCP joint is
transmitted through the
sagittal band connections
to the volar plate.
– The tendon trifurcates over
the proximal phalanx.

4. Anatomy
• Central slip:
– The central continuation
of the extensor tendon.
– Attaches to the dorsal
base of middle phalanx.
– Exerts an extensor
force across the PIP joint.

5. Anatomy
Interossei and lumbricals:
– Provide the intrinsic
contribution to extensor
mechanism.
– Form a lateral band on each
side of the digit, passing
volar to the MCP joint.
– The lateral bands join
with the lateral slips of
the extrinsic extensor
tendon at the level of PIP
joint to form the
conjoined lateral bands.
– The two conjoined lateral
bands then converge
dorsally and insert at the
base of the distal
phalanx as the terminal
extensor tendon.

6. Anatomy
• Triangular Ligament:
– A thin tissue connecting
the conjoined lateral bands over
the middle phalanx.
– Stabilises CLB, Prevents separation
and volar migration of the conjoined
lateral bands when the PIP joint is
flexed.

7. Anatomy
• Transverse Retinacular Ligaments:
– Originate from each side of the PIP joint
volar plate.
– Insert dorsally into the adjacent
conjoined lateral band.
– Stabilize CLB and limit dorsal migration of
the conjoined lateral bands during PIP
joint extension.

8. Anatomy
• Oblique Retinacular Ligaments:
– Arise from the flexor tendon sheath and
volar aspect of the proximal phalanx.
– Course distally to insert onto the dorsal base of
the distal phalanx with the terminal extensor
tendon, thus linking and coordinating PIP and
DIP joint motion.

9. Pathoanatomy
• A well-balanced system exists between intrinsic and
extrinsic tendons, and between flexion and extension forces
across each finger interphalangeal (IP) joint.
• Any injury causing a flexion or extension deformity in one
IP joint can lead to tendon imbalance, creating an opposite deformity in
the adjacent IP joint.
• At DIP joint: FDP flexion force
is counterbalanced by the terminal extensor tendon.
• At PIP joint: flexion forces of the FDP and FDS tendons are
counterbalanced by the extension forces of the conjoined
lateral bands and the central slip of extensor apparatus.

10. Balance between flexion and extension forces
at the finger joints
The single dots represent the axis of flexion-
extension at each joint.
The double dots represent the areas of action
of the corresponding tendons at each joint.

11. What are
the
causes..?
• Systemic e.g.
RA, Gout, Genetic
conditions
• Traumatic
• Degenerative(OA)
• Congenital

12. Systemic
disease
• INTRINSIC PLUS DEFORMITY
• SWAN NECK DEFORMITY
• BUTTON HOLE DEFORMITY
• ULNAR DRIFT OF
FINGERS & RADIAL DEVIATION
OF WRIST

13. Traumatic
• Mallet finger(ED)
• Jersey Finger(FDP)
• Rotational deformity/
Bony deformity post
finger fracture.
• Nerve injury - Claw hand

14. Degenerative
Osteoarthritis
• Small joint OA
• Heberden or Bouchard
node

15. Congenital
- Problems in formation of the parts
• Radial clubhand
• Ulnar clubhand
- Failure of parts of the hand to separate
• Simple syndactyly
• Complex syndactyly
- Duplications of fingers
• Polydactyly
- Undergrowth of fingers
• Underdeveloped fingers or thumbs
- Overgrowth of fingers
• Macrodactyly
- Congenital constriction band syndrome

17. Swan Neck
deformity
• Swan-neck deformity is described as
a flexion posture of the
DIP and hyperextension posture of
the PIP, at times with flexion of the
MCP.

19. • It is caused by muscle
imbalance and may be passively correc
table, depending on the fixation of the
original and secondary deformities.
• Although usually associated with rheu
matoid arthritis, swan-
neck deformity may occur in patients
with lax joints and in patients with co
nditions such as Ehlers-
Danlos syndrome

20. This deformity may begin as
a mallet deformity associated with a dis
ruption of the extensor tendon
at the distal joint
with secondary overpull of
the central tendon, causing hyperextens
ion of the lax proximal interphalangeal
joint. The proximal interphalangeal
joint may actively flex normally.
Or the deformity may begin at the proxi
mal interphalangeal joint because synovi
tis causes herniation of the capsule, tig
htening of the lateral bands and central
tendon, and eventual adherence of the l
ateral bands in a fixed dorsal position, s
o they can no longer slide over the cond
yles when the proximal interphalangeal j
oint is flexed

23. Management
Figure of eight ring splint
FDS tenodesis
Lateral band mobilization
Arthrodesis / arthroplasty

25. Boutonniere
deformity
(Buttonhole)
• Fixed flexion of the PIP
& hyperextension of the DIP joint
• Due to interruption or
stretching of the central slip of the
extensor tendon,
forcing the lateral Bands to begin sublux
ating volarward.

26. Boutonnière deformity. A, Primary synovitis of proximal interphalangeal (PIP) joint can lead to
attenuation of overlying central slip and dorsal capsule and increased flexion at PIP joint. Lateral band subluxation volar
to axis of rotation of PIP joint can lead in time to hyperextension. Contraction of oblique retinacular ligament, which
originates from flexor sheath and inserts into dorsal base of distal phalanx, can lead to extension contracture of distal
interphalangeal joint. B, Clinical photograph illustrates flexion posture of PIP
joint and hyperextension posture of distal interphalangeal joint in boutonnière deformity.

28. • Prevent extensor tendon complete rupture.
• Reduce swelling and pain.
• Prevent PIP joint flexion contracture.
• Prevent lateral band subluxation.
• Prevent oblique retinacular ligament contracture.
• Restore AROM/PROM of MCP, PIP, and DIP joints.
• Maintain ROM of uninvolved joints of the upper extremity.
• Return to previous level of function
Treatment Goals

29. Mallet
Finger
• An injury that involves disruption
of the extensor mechanism at the
level of the distal interphalangeal
(DIP) joint.

30. Alternative Names
• Baseball finger
• Drop finger

31. Mechanism of Injury
• Most
common mechanism:
– Sudden forced flexion of the
extended fingertip.
– This results in either:
• stretching or tearing
of extensor tendon
substance or
• avulsion of tendon insertion from
the dorsum of distal phalanx,
with or without a fragment of
bone.

32. Depending upon whether the thin extensor tendon is torn in its substance or pulls off a
small piece of bone at its insertion, two types are recognized:
 Mallet finger of tendon origin.
 Mallet finger of bony origin.

33. Mechanism of Injury
• Less frequent mechanism:
– Forced hyperextension of the DIP joint.
– This causes fracture at the dorsal base of the distal phalanx.
• Open injuries are caused by a laceration, crush, or deep abrasion.
• With a mallet injury, the delicate balance between flexion and
extension forces is disrupted.
• The following sequence of events occurs:
– Discontinuity of the terminal extensor tendon
– Migration of extensor apparatus proximally
– Increased extensor tone at PIP relative to DIP joint.
– Early or late swan neck deformity (hyperextension of PIP joint
with concomitant flexion of DIP joint) can occur.

34. Classification Acute vs. Chronic
• Acute mallet deformities = those occurring within 4
weeks of injury.
• Chronic deformities = those presenting later than 4 weeks from
injury.

35. Classification Doyle Classification
• Type I: Closed injury, with or
without a small avulsion fracture
at the dorsal base of distal
phalanx.
• Type II: open tendon injuries
caused by laceration at or around
the DIP joint.
• Type III: also open injuries; they
occur from a deep soft-tissue
abrasion with loss of skin and
tendon substance.
• Type IV: mallet fractures

36. Clinical Evaluation
• Recognition and diagnosis of a mallet finger are
relatively straightforward.
• Patients present with pain, deformity, and/or difficulty
using the affected finger.

37. Clinical Evaluation
• Inspection:
– Soft tissues
– Deformity:
• Most patients develop an extensor lag
at the DIP joint immediately after injury.
• The deformity may be delayed by a few
hours or even days.
• Concurrent hyperextension of the PIP
joint (ie, swan neck posture) may be
noted with active finger extension.

38. Clinical Evaluation
• Palpation:
– Tenderness can be elicited in acute injuries with
palpation over the dorsal margin of DIP joint.
• ROM:
– Measure finger MCP and PIP joint motion.

39. Radiographic Evaluation
• Posteroanterior, oblique, and lateral
radiographs of the digit are recommended
to assess for bone injury and
joint alignment.

40. Treatment Options
• Non-surgical:
– Successful in most
mallet injuries.
• Surgical:
– Treatment of either
an acute or
a chronic mallet
finger
– Salvage of failed
prior treatment

41. Jersey
finger
• It is due to avulsion of flexor digitorum profundus
from its insertion on distal phalanx.
• This is the opposite of ‘mallet finger’ and the
patient is unable to flex the distal interphalangeal
joint.
• It is seen in football and rugby players .