Hand Injuries Flashcards
What are the 5 major retaining structures of the IP joints?
- Volar plate
- True collaterals
- Accessory collaterals
- Central slip (part of extensor hood mechanism)
- FDS/FDP
What is the function of the central slip?
Holds the extensor mechanism on the dorsal side, including the lateral bands
What is the function of the volar plate?
Limits extension at the IP joints
Where do the volar plates occur?
At all of the IP joints, another version of them at the MCP joints
What is the common mechanism of injury for the volar plate?
Ball on the end of the finger, commonly results in dorsal dislocation/subluxation
How do you test for a volar plate injury?
- Palpation of volar plate
- Passive extension of IP
- Anterior glide
How are VP injuries graded?
Grade 1: Sprain/stable
Grade 2: Instability, often bone flake
Grade 3: More than 30% volar lip disruption (#) subluxation
How is oedema in VP injuries managed?
Coban tape
How are grade I VP injuries managed?
- Buddy taping 3-4/52
- Isolated tendon exercises
- Beware of loaded extension
How are grade II VP injuries managed?
- Extension block splint in 30-60 degrees for 3-4/52
- Then buddy taping
- Active exercises & strength
- Avoid loaded extension 6-8/52
How are grade III VP injuries managed?
- > 40% articular surface then ORIF
- <40% then gutter splint 3/52 then manage as grade II
What are some of the complications of VP injuries?
- Swan neck deformity
- Flexion contracture (VP heals in shortened position)
What are some of the causes of swan neck deformity?
- Dorsal dislocation PIP
- Imbalance from mallet injury, tight oblique retinacular ligament
- RA changes MCP/PIPs
- Develops over time
What is the function of the accessory and true collaterals?
- TCL: Stability in flexion
- ACL: Stability in extension (with VP)
How are the collaterals tested?
- TCL: In 30 degrees flexion
- ACL: At 0 degrees
How are collateral ligament injuries managed?
No deformity: Buddy tape 4-6/52, graded exercises
Presence of - VP involvement - Ligament interposition post reduction - Large avulsed fracture indicates need for ORIF and/or splintage
What are some of the complications of collateral ligament injuries?
- Valgus/varus deformity
- Scissoring of fingers
- Unable to make a fist
- Need to clarify bony status
- ST tightness
Where does the central slip attach?
Dorsal aspect of the PIP
What happens if the central slip is ruptured? (E.g. dorsal dislocation)
Lateral bands are able to slip forward
How do you test for a central slip?
Palpate dorsal PIP: Boggy and tender
Elson’s test:
- Wrist & MCPs flexed
- Patient extends against resistance at MP
- +ve if PIP flexes or weakness
Why is a central slip a NTBM injury?
Because they don’t have a great capacity to heal on their own
What is the surgical treatment for a central slip?
- Tendon repair
- K-wire 3/52 then splints
- Mobilise
- Scar management vital to outcome
- DIP free to flex to keep lateral bands from tightening
- No passive PIP flexion for 8-12/52
What is the conservative treatment for a central slip?
- Splint PIP in extension 6-8/52, DIP free
- Graded mobilisation
What are the complications of a central slip?
- Linked with volar PIP dislocation, forced flexion injury, laceration, fracture
- Boutonniere deformity (PIP flexed, DIP extended)
