Tendon injuries of hand

1. TENDON INJURIES OF HAND
Maj Vivek Mathew Philip

2.  ANATOMY
 FLEXOR TENDON INJURIES
 EXTENSOR TENDON INJURIES
 SPECIAL CONDITIONS

3. INTRODUCTION
 Anatomical position

4. INTRODUCTION
 Definition:
 Tendon injuries are common
 Exact incidence is unknown
 Surgeon’s goal: Expeditious return to full function

5. CARPAL TUNNEL

6.  FDP and FDS tendons have
fibrous sheaths on the palmar
aspect of the digits
 Extent:ant to MCPJ to the distal
phalanges;
 Fibrous arches and cruciate
(cross-shaped) ligaments, which
are attached posteriorly to the
margins of the phalanges and to
the palmar ligaments
 hold the tendons to the bony
plane and prevent the tendons
from bowing when the digits are
flexed.
 the tendons are surrounded by a
synovial sheath.

7. EXTENSOR HOODS
 ED and EPL tendons expand
over the proximal phalanges to
form complex 'extensor hoods'
or 'dorsal digital expansions' .
 EDM,EIP and EPB endons join
these hoods.
 triangular in shape, with: the
apex attached to the distal
phalanx;
 the central region attached to
the middle phalanx
 base wrapped around the sides
of the MCPJ and corners attach
mainly to the deep transverse
metacarpal ligaments

8. EXTENSOR HOODS
 The lumbrical, interossei,
and abductor digiti minimi
muscles attach to the
extensor hoods.
 In the thumb, the
adductor pollicis and
abductor pollicis brevis
muscles insert into and
anchor the extensor hood.

9. FUNCTION OF DDE

10. INTEROSSEI

11. BLOOD SUPPLY

14. BASIC PRINCIPLES (Sterling Bunnell)
 Exact knowledge of pertinent anatomy and
physiology
 Sound clinical judgment
 Strict atraumatic surgical technique
 “No Man’s Land” – Area within digital flexor sheath,
advised not to repair tendon injuries in this zone

15.  DILEMMA
 Despite modern advances, good results after flexor
tendon repair are not uniformly obtained.
 Should both tendons be repaired or just the FDP?
 Should the sheath be excised or repaired?
 What type of sutures should be utilized?
 What type of postoperative motion most beneficial?

16. ANATOMY
 The tendons of the nine
digital flexors enter the
proximal aspect of the carpal
tunnel in a fairly constant
relationship.
 The most superficial tendons
are the FDS tendons to the
long and ring fingers.
 Immediately beneath them
are the FDS tendons to the
index and little fingers.
 In the deepest layer are four
tendons of the FDP and the
FPL.

17. Anatomy
 Flexor tendon system consists of intrinsic and
extrinsic components
 Extrinsics:
 FDP: flexing the DIP joint
 FDS: Flexing the PIP Joint
 FPL: Flexing the IP joint of the thumb
 Intrinsics:
 Lumbricals: Flex the MCP joints and Extend the IP
joints

18. FDP inserts on
base of distal
phalanx
FDS inserts on
sides of middle
phalanx
FPL inserts on
proximal portion
of the distal
phalanx

19. GOAL
 Primary repair of injured flexor tendons within
the digital sheath is currently accepted.
 Despite Modern advances, good results following
flexor tendon repair is not uniformly obtained.
 Control the inevitable scar formation that interferes
with the beautiful gliding mechanism within the
flexor tendon system

20. FLEXOR TENDONS
 FDP and FDS tendons fibrous
sheaths on the palmar aspect of
the digits
 Extent:ant to MCPJ to the distal
phalanges;
 Fibrous arches and cruciate
(cross-shaped) ligaments, which
are attached posteriorly to the
margins of the phalanges and to
the palmar ligaments
 hold the tendons to the bony
plane and prevent the tendons
from bowing when the digits are
flexed.
 the tendons are surrounded by a
synovial sheath.

21.  Synovial sheath is reinforced by a
system of fibrous pulleys
 5 annular pulleys (A) and
 3 Cruciform pulleys (C)
 A1: 8-10 mm over MCPJ
 A2: 18-20mm over proximal phalanx
 A3: 2-4 mm over PIPJ
 A4: 10-12mm over middle phalanx
 A5: 2-4 mm over DIPJ
 C1, C2, C3 proximal to A3, A4, A5
 Allow shortening of the pulley system in flexion
 A2 and A4 are considered most important.
Their disruption leads to bowstringing,
reduced mechanical efficiency and decreased
flexion.

22.  Function: increase the
mechanical efficiency
by preventing
bowstringing

23. PULLEY BIOMECHANICS

24. ZONES OF FLEXOR TENDON INJURY
 Zone I: Between insertion of FDP
and FDS
 Zone II: From insertion of FDS to
A1 Pulley
 Zone III: Between A1 pulley and
distal limit of carpal tunnel
 Zone IV: Within the carpal tunnel
 Zone V: Between the entrance of
Carpal tunnel and musculo-
tendinous junction.
 Thumb zones:
 I: Distal to IPJ
 II: from A1 to IPJ
 III: Thenar eminence

25. Zone V
The Flexor tendons start
in the distal third of the
forearm at the
musculotendinous
junction
The superficialis group
lies palmar to the
conjoined profundus
tendon group covered
by loose subcutaneous
tissue and skin.

26.  Zone IV
 FPL and FDM enters its
continuous sheath
which becomes the
radial and ulnar bursae.
 The FDS and the FDP
also enter a large sheath
and lie in the carpal
tunnell

27. Zone III
The Lumbrical
muscles
originate from
the FDP just
distal to the
carpal canal
up to the
beginning of the
fibroosseous
canal

28. Zone II
 The flexor synovial
sheath begins at the
neck of the metacarpal.
 The sheath is a double-
wall hallow sealed at
both ends
 FDS is in a single layer
volar to FDP
 Each Tendon splits that
diverges and wraps
around FDP

29. Synovium membrane
of the flexor tendon
consists of two layers:
 Visceral layer: around
the structure within
the sheath
 Parietal layer: covers
internal aspect of the
pulley system

30. FIBRO-OSSEOUS SHEATH
 Allows smooth gliding of the tendon
 Facilitates nutrition to the tendon by synovial
diffusion
 Tendons are enclosed within this sheath and was
defined as “No Man’s Land”, because of the generally
worse outcome associated with this repair.

31. CAMPER’S CHIASMA
 In each finger, the FDS
tendon enters the A1 pulley
and divides into two equal
halves that rotate laterally
and then dorsally.
 The two slips rejoin deep to
the FDP tendon over the
distal aspect of the proximal
phalanx and the palmar plate
of the PIP joint at Camper's
chiasma
 Insert as two separate slips
on the volar aspect of the
middle phalanx.

32. Nutrition in Z2
 Dual Source:
 Vascular
 Synovial diffusion
 Vascular: Segmental
vessels arising from the
paratenon enter the
tendons and travel
longitudinally between
the fasicles.

33. Vincular System
Flexor tendon receives
blood supply within the
tendon sheath
Each tendon is supplied by
a short Vinculum
(Vinculum Breve) and a
long Vinculum
(Vinculum Longus
VBP arises from distal transverse
digital artery at DIP
VBS & VLP from Central Transverse
digital artery at PIP
VLS arises just distal to MCP from
proximal transverse digital artery

34. NUTRITION
In summary
 In distal forearm and palm: Perfusion
from longitudinally oriented vessels
over the paratenon
 Within the digital sheath: Dual source
of nutrition:
 Synovial fluid diffusion
 Vincular system
 Diffusion is more important than
perfusion

35. TENDON HEALING
 Tendons are capable of actively participating in
the repair process through Intrinsic Healing
 Intrinsic Tendon healing occurs in three
phases:
 Inflammation
 Active repair
 Remodeling

37.  Early tendon motion has significant role in
modifying the repair response
 Mobilized tendons showed progressively greater
ultimate load compared with immobilized tendons
 Studies confirm “Wolff’s law” which states that the
strength of a healing tendon is proportional to the
controlled stress applied to it

38. BASIC PRINCIPLES OF REPAIR
 All flexor tendon repairs should be done in the OR
 Use of either general or axillary block
 Use tourniquet unless contraindicated
 Cleanse and debride the wound

39. POST OPERATIVE THERAPY
 Critical part of treatment for flexor tendon repair
 Early passive-motion protocols
 Early Active motion

40.  EARLY PASSIVE-MOTION PROTOCOLS
 Dorsal blocking splint to maintain wrist and MCP in flexion
and block extension
 Kleinert protocol uses rubber bands to maintain digital
flexion while allowing active extension
 Extrinsic flexors are relaxed during active extension
 Active extension moves the repaired tendon without
resistance
 When the extensors are
relaxed,fingers are pulled back
in flexion by the rubber bands
 4-5 weeks active flexion
 8 weeks resisted flexion

41. Early Active Motion
 Early Active motion
is used with
increasing frequency
 This protocol
requires experience
 Therapist
 Surgeon
 Reliable patient
 Strong tendon repair

42. Ideal tendon repair:
 Easy placement of sutures in the
tendon
 Secure suture knots
 Smooth junction of tendon ends
without gapping
 Minimal interference with vascularity
 strength

43. TECHNIQUES
 Retrieve the tendon ends
through the sheath in an
atraumatic manner
 Maintain the integrity of
the pulley system
(especially A2 and A4)
 Create “retinacular
window” described by
Lister for preserving the
flexor sheath

44. TECHNIQUES
 Extend the original
laceration for better
exposure
 Zigzag
 Midlateral
 Avoid linear scars that
cross flexion crease

45.  Milk the forearm with the wrist and MCP in flexion
 Do not attempt blind retrieval more than twice
 Make a separate incision if necessary
 Use a pediatric feeding
tube to retrieve tendon
stump

46. Suture Technique
 Suture material
 Non reactive
 Pliable
 Small caliber
 Strong
 Easy to handle
 Common material: Ethibond, Nylon, proline

47. The strength of the tendon repair is
proportional to the number of core
sutures that cross the tenorrhaphy site.
6-0 proline epitendinous suture is added
 “tidy up” the repair
 Contributes to the strength of the repair

51.  McCarthy in 1996 survey: 72% used this
technique

58. Six Strand Technique

59. Tendon Sheath Repair?
 Role of diffusion of nutrients from synovial fluid
 Tendon within the sheath have an intrinsic capacity
for healing
 Gelberman and woo in 1990 study on dogs
 Reconstruction of the sheath did not significantly
improve repaired tendons treated with early motion
rehabilitation.

60. Partial Tendon Laceration
 Rupture, entrapment, triggering
 Partial laceration involving 60% or less
are best treated by early mobilization
WITHOUT tenorrhaphy

61. Profundus Tendon Avulsion
 Avulsion of FDP from
its insertion by forced
hyperextension
 Most common in the
ring finger
 Leddy and Parker
classification
 Based on the level to
which the tendon
retracts
 Status of the tendon
vascular anatomy

62. Type I
 Profundus has
retracted proximally
into the palm
 Surgery should be
done in 7-10 days
before a fixed
muscular
contracture develops
 Least common

63.  Distal digital exposure to
confirm diagnosis
 In Type I, a second distal
palm incision will be
needed
 Tendon is reinserted into
the base of distal phalanx
 Distally based periosteal
flap is raised distal to volar
plate
 Tendon is sutured through
drill holes in the distal
phalanx and button tied
over the nail plate

64.  Maintain flexion of the wrist and MCPJ in a dorsal
blocking splint
 Begin early passive motion
 Active motion in 3-4 weeks

65. Type II
 Profundus retracts to PIP
 Disruption of Vinculum
Breve
 Nutrition is maintained by
Vinculum longum
 May be repaired up to 3
months
 Delay may convert type II
into a type I if longum
subsequently ruptures

66. Type III
 Attached bone
fragment that
fractures off the
volar base of distal
phalanx
 A4 pulley prevents
proximal retraction
 Both Vinculae are
preserved

67.  Type III attention is
turned to ORIF

69. COMPLICATIONS
 Short term:
 Infection
 Injury to
neurovascular
structures or
pulley system
 Abnormal scarring
 Long term:
 Adhesion
 Rupture
 Joint contracture
 triggering

70. Complications
Adhesion
 Most common complication despite early
motion protocols
 Tenolysis when patients progressive gain
in digital motion has plateaued, usually 3-
6 months after repair

71. Tendon Rupture
 Noted by the patient at “popping” in the
hand
 7-10 days postop when tensile strength is
weakest
 MRI may help in diagnosis
Flexion contracture
 FDP advancement more than 1 cm may
lead to flexion contracture and weakened
hand grip because of quadrigia effect

72. Flexion contracture
 FDP advancement
more than 1 cm
may lead to flexion
contracture and
weakened hand
grip because of
quadrigia effect

73. Quadriga effect
 Over advancement of the
FDP
- weak grasp in
remaining fingers due to
FDP tethering;
- if one FDP is
tethered, the others can
not shorten;
- there is loss of
flexion in other digits and
patient may be unable to
make a full fist

74. Triggering and entrapment
Especially when sheath is not
repaired
Post traumatic regional pain
syndromes
Cold intolerance
RSD

75. LATE RECONSTRUCTION

76. Indications:
Primary repair is not possible
Segmental loss
Loss of the pulley system
Compromised wound
Delayed diagnosis
Scarring and rupture

77.  Consideration for flexor
tendon reconstruction
 Boyes’ grading scale of
flexor tendon injury
provides a guideline in
determining the
achievable outcome
after flexion tendon
reconstruction

78.  The position of the digit to be reconstructed should
be considered
 Ulnar ring and small digits need complete flexion to
provide strong grip
 Full flexion of radial digits are less important because
they are used for precision pinch
 Full flexion of the thumb is less important than providing
a stable and sensate thumb with adequate length

79.  Prerequisite for flexor tendon reconstruction
 Adequate soft tissue coverage
 Digital vascularity
 Healed fractures
 Passively supple joints
 Return of sensibility

80.  Reconstruction
Modalities
 Tenolysis
 Tendon advancement
 Tendon transfer
 Tendon grafts with or
without creation of
artificial tendon sheath
by silicon rod
implantation
 Alternatives
 Amputation
 Joint fusion
 Tenodesis
 Caspulodesis

81. Tendon grafting
 Used when injury has resulted in a tendon gap
 Can be carried out in one or two stages
 One stage
 Acute trauma: segment of flexor tendon lost in a clean,
vascularized wound with intact pulley
 Tenolysis: when tendon is deemed inadequate to permit
immediate postoperative motion

82. TWO STAGE
 Direct repair is not possible
 Scarred tendon bed in which primary
tendon grafting has a low chance of
gliding
 Reconstruction of profundus tendon
when sublimis is intact and there are
existing scars

83. Two stage technique
 Create a supple pseudosynovial sheath
by implanting a silicone rod
 Soft tissue coverage or pulley
reconstruction is performed at the first
stage
 8 weeks later, when psuedosynovial
sheath is formed, the rod is replaced by
a tendon graft

84.  Palmaris longus and
plantaris
 Tendon grafts that
include synovial sheath
 Toe extensors
 Other donors
 EDC to index,
 EDL to 2nd, 3rd and 4th
toes,
 EIP /EDQ

85. Tendon Juncture
 Pulvertaft weave, with two or more passes through
the proximal motor tendon

86.  Distal end may be secured in multiple ways

87.  Tension adjustment
 Proximal weave is adjusted
 Wrist is extended to flex
the fingers into the cascade
of the hand
 Overcorrect slightly
because some stretching
occurs after surgery

88. PULLEY RECONSTRUCTION
 Must be done during the first stage
 Well-healed pulley reconstruction facilitates early
mobilization and gliding of tendon graft
 Reconstruction during the second stage increases the
likelihood of pulley rupture and adhesion formation
 Material used
 Autogenous grafts: PL, Plantaris, to extensors, EIP,
Extensor retinaculum, fascia lata

89. Rehabilitation
Controlled passive motion protocol
started immediately
Active motion at 3 weeks
Strengthening exercised at 6 weeks

91. Intrinsic
System
ulnar and
median N
innervated
Extensor Tendons
Extrinsic
System
radial N
innervated

92. Extrinsic Extensors
Wrist Extensors: ECRL, ECRB, ECU
Finger Extensors: EDC, EIP, EDQM
Thumb Extensors: APL, EPL, EPB

93. Finger Extensors
EDC has a common muscle belly with
multiple tendons
EIP & EDM lie on the ulnar side of the
respective EDC tendon

94. Thumb Extensors
 APL inserts on the
metacarpal and
radially abducts it
 EPB inserts on
proximal phalanx and
extends MCP Joint
 EPL inserts on distal
phalanx and extends
IP Joint

95. Testing the Extrinsics
 APL:Palpate with thumb abduction
 EPB:MP extension with IP flexion,
palpate tendon
 EPL:Palpate tendon with
retropulsed thumb
 EDC:Test with wrist in
neutral-extension

96. Testing the Extrinsics

97. Compartments
at Wrist

99. Intrinsic Extensors
Lumbricals
Interossei: 4
dorsal, 3 volar

100. EDC tendon trifurcates into
central slip & 2 lateral slips
Intrinsic extensor
tendons join the lateral
slips to form the lateral
bands
Extensor Apparatus

102. Lateral Band

103. Lateral Band

104.  The central slip inserting on
the base of the middle
phalanx and two lateral slips
inserting to the distal
phalanx.
Winslow’s Rhombus

105. Juncturae Tendinium

106. ANATOMICAL PATTERNS OF THE
EXTENSORS TO THE FINGERS
 The most common
patterns
 single extensor indicis
proprius inserting to the
ulnar side of the index
extensor digitorum
communis
 a single extensor
digitorum communis to
the index finger
 ,
 a single extensor
digitorum communis to
the long finger,
 a double extensor
digitorum communis to
the ring finger,
 an absent extensor
digitorum communis to
the small
 finger, and a double
extensor digiti quinti with
double insertions.
 ,

107. JUNCTURAE TENDINIUM
Functional roles:
• spacing of ED tendons
• force redistribution
• coordinate extension
• MP stabilization
 Ring finger has least independent extension due to
the orientation of the juncturae

108. SAGITTAL BANDS

109. Sagittal Bands
 Stabilize the common
extensor during digital
flexion over MCPJ
 Limit the excursion of
the common extensor
tendon during digital
extension

110. Sagittal bands
 EDC allows extension of
MP joint via insertion
onto the sagittal bands
 There is usually no
tendinous insertion of
EDC to the dorsal base of
the proximal phalanx.

111.  No MP joint
hyperextension: EDC
extends MP, PIP, and DIP
joints even in the
absence of intrinsic
muscle function.

112.  INTRINSIC PARALYSIS:
“slack” develops in EDC
system distal to the
sagittal bands all
producing a flexion
posture at PIP and DIP
joints, the “claw” finger.

113. Interosseous
Hood

114. Transverse & oblique
fibers of Interosseous
Hood
1) EDC Tendon
2) Central Slip
3) Lateral Slip
4) Intertendinous Connection
5) Volar Interosseous Muscle
6) Lumbrical Muscle
7) Interosseuos Hood (Transverse)
8) Interosseuos Hood (Oblique)
9) Lateral band
4 7 1
3
9
8
65
2

115. Triangular
Ligament
Connects both
lateral bands over
the
middle phalanx

116. 1
6
5
4
2
3
PIP Joint
• Limits the volar and
lateral shifting of the
lateral conjoined
extensor tendon during
digital flexion
• In boutonniere
deformity  elongated
• In fixed swan neck
deformity  retracted

117. Retinacular Ligament
Transverse bands:
Lateral continuation of
the triangular ligament
extending from the
lateral margin of the
lateral conjoined
extensor tendon to PIPJ
articular volar plate

119. Mechanics
Extensor apparatus
produces finger extension &
collaborates in finger flexion

120. Dynamics of Extension
Excursion Total Wrist MP PIP DIP
Index 54mm 38 15 2 0
Middle 55 41 16 3 0
Ring 55 39 11 3 0
Little 35 20 12 2 0
Thumb 58 33 7 6 8

121. Finger Extension
Combined action of long extensor & intrinsics

122. Hyperextension
Extension of IPJ’s with hyperextension of MCPJ can be possible
because of the strong traction of intrinsics (lumbricals)

123. Linked Extension
Normal conditions extension of MP  extension of DP

124. Extensor zones as described by Verdan

125. Repair Techniques

126. Repair Techniques

127. Doyle[25] proposed the following techniques for extensor tendon repair:
 Zone 1 (DIP joint): Running suture incorporating skin and tendon.
 Zone 2 (middle phalanx): Running 5-0 stitch near cut edge of tendon,
completed with “basket-weave” or “Chinese fingertrap” type of cross-
stitch on the dorsal surface of the tendon .
 Zones 3 through 5 in fingers, and zones 2 and 3 in thumb: Modified
Kessler suture of 4-0 synthetic material in the thickest portion of the
tendon. A 5-0 cross-stitch tied to itself at the beginning and end is run on
the dorsal surface of the tendon
 Zones 6 and 7: Same as for zones 3 through 5 except the cross-stitch is run
around the entire circumference of the tendon, if feasible

128. Injuries to Specific Zones

129. Mallet Finger
 Due to disruption of terminal tendon
 Caused by forced flexion,
hyperextension or torsion
 Can result in 20 Swan Neck Deformity
 Early or late volar subluxation of DIP

130. Closed Rupture of Extensor Tendon
with Avulsion Fracture of P3

131. Mallet Finger
Classification - Lange & Engber
I. Extensor tendon injury
a. rupture/attenuation
b. laceration
II. Extensor avulsion
III. Mallet #
a. transepiphyseal # of children
b. hyperextension mallet without
subluxation
c. hyperextension mallet with subluxation

133. Hyperextension Splint
A tendinous
injury generally
can be improved
by
extension
splinting up to 6
months from the
time of injury

134. Splints for Mallet

135. Mallet Surgery
 Direct repair + K-wire
 Pullout wire tied over padded button + K-wire
 Central slip tenotomy
 Tenodermodesis
 Tendon grafting - extensor or ORL
 Extension block wiring (Ischiguro)
 Arthrodesis

136. Direct repair + K-wire
Failure of conservative treatment

137. Exposure and Direct Repair of the Tendon

138. DIP joint pinned in extension

139. Pullout Wire and K pin

140. Zone II (P2) Injury
 Usually lacerations
 Result in Mallet deformity
 Approximate with horizontal
loop sutures
 DIP pinning or splint
 Post op as in Mallet

141. Swan-neck

142. Zone III Injury
Injury over PIP Joint
Central slip disruption

143. Boutonniere deformity

144. Zone IV Injury
 Usually partial as P1 is rounded
 Not much retraction of cut ends
 Repair / Splinting for 3-4 weeks or
6 wks if total laceration

145. Zone V Injury
 Extensor lag usually minimal due to
incomplete injury of sagittal band
 Simple Lacerations – direct repair
 Extensor dislocations – pathology in the proximal
radial sagittal band. Classically involves MF

146. Closed Sagittal Band Injuries
Rayan GM, Murray D J Hand Surg 1994

147. Treatment of Sagittal Band Injuries
 Conservative
volar splint, cast, buddy taping for 4-6 wks. Results
satisfactory when treated within 3 wks
 Surgical
centralization of tendon by repair or reconstruction
of the radial band

148. Composite Tissue loss in Zone VI
 Meticulous debridement and Flap cover with primary /
secondary extensor reconstruction
 Staged reconstruction with free flaps, silicon tendon
implants followed by ext grafts
 Single stage primary bone + tendon graft + free flaps
 Dorsalis pedis tendocutaneous flap

149. Zone VII Injury
 Area under the retinaculum with
6 compartments
 Problem of retraction, tendon
adhesion, bowstringing due to
injury to the retinaculum
 Closed tendon ruptures are also seen in this zone

150.  Closed tendon ruptures of EPL, EDC mainly
reported with Colles’ #, Smith #, Galeazzi #, ulnar
subluxn, Madelung deformity, distal ulna excision,
Keinbocks
 Proposed to be due to avascular necrosis of the
tendon, attrition
 Treated by tendon transfers (preferably EIP) or
grafting
Zone VII Injury

151. Zone VIII Injuries
 Usually multiple tendons are
affected
 Repair at the musculotendinous
junctions are difficult
 Associated nerve injuries must be identified

152. Thumb Tendons
 Mallet thumb rare
 EPB anomalies commonplace
 Delayed rupture of EPL may follow fractures
eg. Colles, Galleazi, Smith’s, Madelung’s
deformity
 EPL repair pitfalls
retraction - may require re-routing

153. Injury to Thumb Extensor
Zone I and II
 Mallet injuries are rare
 Operative treatment is a good option
esp in open lacerations
Zone V – VII
 MCP area is designated zone V
Extensor lag usually minimal
 Proximal to zone V, EPL retracts far
 Repair >1mo requires rerouting EPL from Listers
tubercle

154. Long term results
 60% has associated injuries
 Excellent or good results in 62% (TAM –89% or
2300 ) when not associated with other injuries
 45% (TAM 82% or 2120) when associated with
other injuries
 Distal zones (I-IV) results less favorable
 Loss of flexion is the most significant
complication

155. Summary
 Extension of digits is an intricate and complex
mechanism
 Extensor tendon injuries are common
 Loss of flexion is significant
 The deformity depends on the zone of injury

156. Summary
 Zone III/IV injury has a poorer result
 Associated injury to joint, bone etc results in
poorer results
 EPM and EAM gives better results