Arthrodesis of the Pastern Joint (Proximal Interphalangeal Joint)

Question 1

What is the layman terms for the Proximal Interphalangeal Joint?

Answer 1

Pastern Joint

Question 2

What are the indications for Arthrodesis of the Proximal Interphalangeal Joint?

Answer 2

1) DJD of the pastern joint (High ring Bone)
2) Pastern Luxation
3) Fracture second Phalanx
4) Septic arthritis of the Pastern Joint

Question 3

What breed of horse is commonly affected with injury to the Pastern Joint (PIP)

Answer 3

Barrel racing QH

-present acutely lame

Question 4

What is the laymans terms for Osteophyte/ DJD formation of the Pastern joint?

Answer 4

High ring Bone

Question 5

What is the laymans terms for Osteophyte formation/ DJD of the coffin joint?

Answer 5

Low ring bone

Question 6

What are some clinical signs in a horse with High ring bone or low ring bone?

Answer 6

• Hx chronic lamness (2/5)

- lameness is worse following distal limb flexion

Question 7

In a Case of High ring bone or low ring bone, why does the body make proliferative bone?

Answer 7

Bone proliferation is made to try and stabilize the joint

Question 8

What medical treatment can be used for High Ring bone (OA of PIP)?

Answer 8

• NSAIDs
• reduce work
• Natural ankylosis (unlikely)

Question 9

What are the Primary principles of PIP (Pastern joint) arthrodesis?

Answer 9

1) remove all articular cartilage

2) Maintain rigid stability in the joint

Question 10

Why do you want to maintain rigid stability in the joint for PIP arthrodesis?

Answer 10

*minimizes new bone formation

Question 11

What surgical techniques can be used for Pastern Joint arthrodesis?

Answer 11

1) Trans-articular lag screws
2) Dorsal plate (DCP or LCP)
3) trans-articular lag screw and dorsal plate

Question 12

What is the best surgical technique for arthrodesis of the PIP?
-WHY?

Answer 12

trans-articular lag-screws and dorsal plate

• better rigidity
• better stability
• better comfort
• shorter time in cast
• shorter return to function
• decreased hospitalization time
• less peri-articular new bone formation on dorsal aspect

Question 13

What type of incision in required for PIP arthrodesis?

Answer 13

Inverted T incision

• Longitudinal incision from middle P1 distally to 2cm proximal to the coronary band
• transverse incision extended laterally and medially

REMEMBER to stay 2 cm proximal to the coronary band!!!!

Question 14

What structure is exposed during a inverted T incision for PIP arthrodesis?

Answer 14

Common digital extensor Tendon

Question 15

What type of incision is made into the extensor tendon during PIP arthrodesis?

Answer 15

Inverted V incision

Question 16

What ligaments need to be transected in a Pastern joint arthrodesis to gain access to the joint?

Answer 16

Collateral ligaments

Question 17

What is osteostixis?

Answer 17

• Holes made into the subchondral bone plate
• uses a 2.5mm drill bit
• mesenchymal cells from bone marrow (which provide growth factors)

Question 18

What is the surgical technique for PIP arthrodesis?

Answer 18

• extend foot (pastern in normal position)
• 3 hole plate on dorsal surface axially
• Contour Plate
• 2 holes in P1, 1 hole in P2
• place 2 screws (proximal and distal)

Question 19

What is the surgical technique for TA screw placement?

Answer 19

-enter join mid way between dorsal and palmer corticies
-drill glide hole in P1 (5.5mm bit)
Drill thread hole in P2 (4.0 mm bit)
-Countersink
-Tap. (5.5mm)

Tap and glide always the same!!!

Question 20

Which has the bigger hole the Glide or the thread!!!

-which has bigger screws?

Answer 20

The Glide hole has bigger screws and is bigger

Question 21

What do you take radiographs intra-op and post-op ?

Answer 21

-check placement
-for later comparison (healing check)
-check strain post op : recovery is when they put the most amount of strain on
-

Question 22

Which is better to chose for PIP arthrodesis?

4.5 screws or 5.5 screws and why?

Answer 22

5.5 better purchase and stronger!

Question 23

T/F: A cast should not be place after surgery for PIP arthrodesis?

Answer 23

FALSE

• a distal limb cast should be placed
• or transfixation pin cast

Question 24

What is the preferred technique for PIP arthrodesis?

Answer 24

Trans-articular screws and dorsal Plate

For increased stability!!!!!!!

Question 25

Why do we use a 3 hole plate now instead of a 5 hole plate for PIP arthrodesis ?

Answer 25

5 hole plates impinge tissue on the distal aspect of P2 (coffin joint)

Question 26

When would you use a diverging Double plate technique for PIP arthrodesis?

Answer 26

• P2 fracture with multiple fragments

- clinical judgement

Question 27

What is the success rate for Pastern Arthrodesis for the FORE limb?

Answer 27

81%

Question 28

What is the success rate for Pastern Arthrodesis of the HIND limb?

Answer 28

95%

Question 29

What are the complications of Pastern Arthrodesis?

Answer 29

1) life threatening
2) $$$$
3) difficult to manage
4) success dependent on achieving absolute stability with approved surgical technique and implants)
5) surgeon screws up

Question 30

Most of the time when there are complications with Pastern Arthrodesis it is due to what?

Answer 30

The Surgeon screwing up!

Question 31

What are some of the clinical signs/diagnostic for complications?

Answer 31

• increasing lameness
• imaging (rads/US/termography)
• often due to cast
• CBC, SAA, Monitoring for fever

Question 32

how do you manage complications associated with PIP arthrodesis?

Answer 32

• NSAIDS mainstay!!!!!!
• Alpha2s, opioids (morphine, butorphanol)
• Perineural bupivacaine
• epidurals (hindlimb)
• CRI lidocaine or combo MLK
• gabapentin
• acupuncture
• dont forget the contralateral limb
• deep bedding
• mechanical and vascular support
• balance both feet (softe ride, easy boot cloud)
• asprin, acepromazine, pentoxyfiline

NO SLING!!!!