Extensor Tendon Injuries

Question 1

How do you test for

• ORL tightness
• Intrinsic tightness
• Extrinsic tightness

Answer 1

• ORL tightness
  
  • extension of PIP leads to less DIP flexion
• Intrinsic tightness
  
  • hyperextension of MCP leads to less PIP flexion
• Extrinsic tightness
  
  • flexion of MCP leads to less PIP flexion

Question 2

How do you test for central slip injury?

Answer 2

Elson’s test

• with PIP in max flexion, you normally cannot extend DIP jt because central slip holds extensor apparatus out to length and lateral bands to DIP are lax
• IF central slip injury, can actively extend DIP jt with PIP in maximum flexion

Question 3

What are the extensor zones of the hand/forearm

Answer 3

• 1- DIPJ
• 2- MP
• 3- PIPj
• 4- PP
• 5- MCPj
• 6- MC
• 7- CT
• 8- tendinous extrinsics
• 9- muscle forearm
• T1- IPj
• T2 - PP
• T3- MCPj
• T4- MC
• T5 - CMCj

Question 4

What is the excursion of wrist extensors and digit extensors?

Answer 4

• Wirst - 3cm
• Digit - 5.5cm

Question 5

Describe your extensor repair for each zone

Answer 5

• Zone 1
  
  • dermatotenodesis, running monofilament
  • splint 6wks, then 2wks nighttime
• Zone 2 <50% lacerated
  
  • splint only 1wk then AROM
• Zone 2 - >50% lacerated
  
  • running braided 4-0 + epitendinous 5-0
  • splint 6wks, then 2wks nighttime
  • THUMB - CORE + epitendinous (EPL)
• Zone 3 - central slip
  
  • splint PIP full extension 6ks w DIP and MCP free, then 2wks nighttime
  • IF failed split, volar dislocation, >50% avulsion f# of MP base
  • Acute with large bone segment; OR ->dorsal approach, ORIF w kwire/tension band/miniscrew. If Acute and CS inadequate length, Snow of Aiche repair then splint 6wks. May add Kwire
  • THUMB: CORE + epitendinous EPL EPB, splint extended 3wks
• Zone 4
  
  • centrally can do core/epitendinous. Splint W 30ext, MCP 45-70 flexion, IP straight. Passive extension 1wk, active extension 4wks
• Zone 5
  
  • Ext apparatus - as above
  • Sagittal band
    
    • acute<2wks - flexion block splint to keep MCP at ) for 6wks
    • delayed >2wks - repair , MP extension 1wk then gentle flex/ext exercise
• Zone 6- 7 - as above
• Zone 8 - core repair/epitendinous, splint W ext 40, MCP 20, fingers FREE 5wks
• Zoen 9 - muscle repair figure 8, splint above elbow at 90, W ext 40, MCP 20, fingers free 4wks

Question 6

What is the sequence of extensor imbalance

Answer 6

• swan neck
• boutonniere
• extrinsic tightness
• intrinsic tightness
• extensor subluxation adn ulnar drift

Question 7

What is the origin insertion and function of Sagittal bands

Answer 7

O: EDC tendon

I: Volar plae, intermetacarpal ligament

Fx: maintain EDC central over MCPj, assists in extension of MCP

Question 8

What is the origin insertion and function of TRL

Answer 8

O: flexor sheath

I: Lateral band of lateral conjoined band

Fx: prevent dorsal subluxation of lateral bands

Question 9

What is the origin insertion and function of trasnverse and oblique fibers

Answer 9

O: IO and lumbricals

I: extensor tendon over PP

Fx: assist in MCP flexion

Question 10

What is the origin insertion and function of ORL

Answer 10

O: flexor sheath

I: TT

F: coordinate fx b/w DIP and PIP

Question 11

How do you classify mallet finger injury

Answer 11

Leddy Packer

• 1- Closed, with loss of tendon continuity +/- avulsion F# (most common)
• 2- Open laceration with loss of tnedon continuity
• 3- deep abrasion with loss of tendon substance
• 4A- transepiphyseal plate F#
• 4B - Hyperextension injury involving 20-50% of articular surfcae
• 4C - Hyperextension injury involving >50% of articular surfcae & early/late volar subluxation of PP

Question 12

How do you treat mallet finger according to classification

Answer 12

Type 1 - closed

• splint 6wks then 6wks at night
• if failed, K-wire

Type 2- open

• Dermatotenodesis
• splint 6wks then 6wks at night

Type 3- substance loss

• ST covreage +/- Kwire (FTSG, 2’ intent, local flap)
• splint 6wks then 6wks at night
• may delay recon w graft

Type 4A- transepiphyseal

• CR
• splint 6wks then nighttime 6wks

Type 4B - articular F# 20-50%

• CR. Kwire extension block pinning if unstable
• splint 6wks then 6wks at night

Type 4C - articular >50%/volar sublux DP

• Kwire extension block pinning
  
  • flex DIP, insert pin into MP to wedge fragment
  • extend DP and place longitudinal pin across DP
• Kwire in place 6wks

CHRONIC MALLET

• Attempt splint
• Kwire w dermatotenodesis OR
• Arthrodesis if OA
• Fowler tenotomy - release central slip=>improved DP extension

Question 13

How do you manage a fight bite

Answer 13

• Xray - FB
• I&D, 2’ intention healing
• Joint invovlement - washout, packing, IV abx

Question 14

Describe rehabilitation protocols for extensor repairs

Answer 14

• Immobilization
• Controlled Early Passive (Dynamic Extension Splinting)
  
  • static splint 2wks then DES 4wks
• Early Active

Question 15

What are two methods of central slip injury repair when there is insufficent length/tissue for repair

Answer 15

Snow - distally based flap from extensor aponeurosis

Aiche - bilateral advancement flaps

Question 16

List 3 methods of secondary reconstruction of ruptured unrepaired sagittal bands (with ED slipping into ulnar gutter

Answer 16

• Dorsal Tenodesis
  
  • release ulnar sagittal band
  • on adjacent radial EDC, create longitudinal distally absed flap and wrap around EDC of interest to keep centralized
• Sling procedure
  
  • distally absed flap on injured EDC is used slung around intrinsics or dTMClig
• Dynamic Lumbrical muscle transfer
  
  • transfer lumbrical to serve as a direct antagonist

Question 17

What is a swan neck deformity and the acute and chronic changes which occur

Answer 17

Def: PIP Hyperextension, DIP hyperflexion

ACUTE

• dorsal subluxation of lateral bands
• attenuation of TRL
• laxity of PIP Volar Plate

CHRONIC

• lateral bands contract
• PIP DIPjoint contractures
• extensor tendon adhesions
• joint surface changes

Question 18

What are causes of Swan neck Deformity

Answer 18

@ PIP

• VP injury (dorsal dislocation, synovitis, RA)
• Intrinsic tightness (intrinsic contracture post stroke/CP, RA)
• FDS injury

@ DIP

• chronic Mallet
• shortened MP

Question 19

How do you classify Swan neck deformity

Answer 19

Stage 1 - supple, no tightness/ full AROM/PROM

Stage 2 - Intrinsic tightness - less PIP flexion w MCP extension

Stage 3- LImited PIP PROM - capsule contraction, tendon adhesions

Stage 4 - fixed PIP hyperextension

Question 20

What are treatment options for swan neck deformity

Answer 20

NON-OP

• splint and exercise for contractures and intrinsic tightness

OPERATIVE

1. Correct MP length
2. Repair Mallet
3. Limit PIP hyperextension
   
   1. VP capsulodesis/repair
   2. FDS tensodeis to PP bone (one slip only)
   3. Intrinsic rerouting (ulnar lateral band distally based flap rerouted palmar and into flexor sheath at PP
   4. SORL reconstruction - spiral ORL - tendon graft inserted into drill hole dorsal DP, routed palmar to PIP and insert palmar into drill hole of PP

For ALL, Kwire at 30’ flexion PIP and dorsal block splint for DIP

Question 21

What is boutonniere deformity and features of the deformity

Answer 21

Def: PIP flexion with DIp hyperextension

ALWAYS starts with PIPJ

ACUTE

• central slip discontinuity
• lateral bands sublux volarly and become PIP flexors
• DIP HYPEREXTENSION

CHRONIC

• ORL tightness

Question 22

How is the boutonniere deformity staged?

Answer 22

• 1- central slip disrupted, lat bands dorsal to PIP axis
  
  • PIP extensor lag <30
• 2- volar subluxation of lat bands
  
  • PIP extensor lag >30
• 3- ORL contracture
  
  • limited flexion DIP w PIP flex.+ORL tightness
• 4- Fixed flexion contracture PIP
  
  • contracture of VP, ORL, TRL, collaterals
• 5- PIP arthritis

Question 23

How is boutonniere deformity treated non-operatively?

Answer 23

NON-OPERATIVE

MOST (acute AND chronic) treated non-op successfully

Step 1- restore passive PIP extension

• spliting, capsulotomy

Step 2- Rebalance extensor apparatus

• with PIP fully extended, AROM/PROM of DIP to relocate the lateral bands and ORL

Step 3 - maintain PIP extension

• static splint 8wks PIP only

Question 24

How is boutonniere deformity treated operatively?

Answer 24

OPERATIVE

* requires tenolysis of contracted segemtns (ORL, TRL), repositioning of lat bands and reconstitution of CS

1- Fowler terminal tenotomy (or dolphin - just distal to CS to ensure ORL preserved)

• release TT to allow DIP flexion. Ext apparatus migrates proximally, allows strong flexors to work on DIP and ORL maintains concerted fx of PIP/DIP

2- Extensor apparatus recon (of CS) with tendon graft

• PL graft used- 2drill holes in MP, graft passd through, secured to contralateral lateral band

3- Littler lateral band transfer

• lateral bands (minus the lumbricals) are excised off conjoint bands and centralized to reconstruct CS (extension force transfered form DIP to PIP). ORL and lumbricals left intact and extend IPs

Question 25

What is the cause of extrinsic tightness

Answer 25

* Post-traumatic adhesions, muscle contractures * RA- flexion deformity of MCP/wrist * CP- muscle spasticity

Question 26

What is the treatment for extrinsic tightness

Answer 26

NON-OP * splinting, exercise program OPERATIVE * tenolysis, extrinsic extesor tendon release