Ch 63 - Fractures of the Tibia and Fibula

Question 1

What major muscles attach to the tibia and what is their function?

Answer 1

• Quadriceps femoris (stifle extension)
• Biceps femoris (stifle flexor)
• Caudal part of sartorius (stifle flexor)
• Cranial tibial muscle (tarsal flexor)

Question 2

List the 4 epiphyses of the tibia

Answer 2

• Proximal epiphysis
• Tuberosity epiphysis
• Distal epilphysis
• Medial malleolar epiphysis

Question 3

What is an apophysis?

Answer 3

A traction epiphysis such as the tibial tuberosity

Question 4

How much of the longitudinal length of the tibia is from the proximal and distal epiphyses respectively?

Answer 4

• Proximal 40%
• Distal 60%

Question 5

At what age does the tuberosity epiphysis fuse with the proximal epiphysis?
At what age does the tuberosity physis normally close?

Answer 5

• Fuses to proximal epiphysis 5-9m in large dogs
• Physis closes over 12m in large dogs

Question 6

At what age does the medial malleolar epiphysis fuse to the distal epiphysis?

Answer 6

Very early, approx 4-5m in large breeds.

Question 7

What part of the tibial plateau is articular?

Answer 7

The caudal 1/2

Question 8

What muscles attach to the tibial tuberosity?

Answer 8

• Quadriceps femoral
• Parts of biceps femoris and sartorius

Question 9

What are the main vessels which supply blood to the tibia and fibula?

Answer 9

Tibia
- Cranial tibial artery

Fibula
- Cranial tibial artery (head)
- Peroneal artery (fibula)

Question 10

What vessels and nerves surround the tibia

Answer 10

• Medial saphenous artery and vein and saphenous nerve obliquely cross the medial tibia
• Tibial and popliteal artery along lateral and caudal aspect
• Peroneal and cutaneous nerves along lateral and caudal aspects

Question 11

What can result in a tibial tuberosity avulsion?

Answer 11

Contraction of the quadriceps while the stifle is flexed and the foot is firmly on the ground

Question 12

What is Osgood Schlatter disease?

Answer 12

Considered to be a form of osteochondrosis but has been suggested that it should be classified as a minimally displace tibial tuberosity fracture

Question 13

What leg position can aid in reduction of a tibial tuberosity fracture? What are the repair options?

Answer 13

Hip flexed and stifle extended
Repair options:
- 2 K-wires in a caudoproximal direction (very young small dogs with minimal displacement)
- Pin and tension band (preferred)
- Reattachment of patella tendon to bone tunnel if not enough bone to reattach

Question 14

What are the repair options for a proximal physeal fracture?

Answer 14

Pinning!
- At least 2 cross pins
- Third pin through tuberosity recommened for better stability

Question 15

What are the repair options for proximal metaphyseal fractures?

Answer 15

• IM pin, cross pins, plate, lag screws
• If fibular head had detacted from tibia, should be reattached with screws
• If comminuted, plate must be placed on side of comminution to act as buttress plate

Question 16

What is the ideal pin insertion point for normograde tibial IM pinning?
What is the recommended size?

Answer 16

• Approx 1/3 - 1/2 distance from cranial tibial tuberosity to medial condyle of tibia
• 50% width of isthmus (smaller that usually recommended as needs to bend with s-shaped bone)
• 30-40% if using with a plate

Question 17

What unique consideration needs to be realised when placing cerclage around the distal tibia?

Answer 17

The tibia and fibula are closely associated from mid-diaphysis distally usually requiring the cerclage wire to be placed around both bones

Question 18

What is the reported rate of non-union in tibial fracture repairs?

Answer 18

4.1%

Question 19

What are the repair options for distial tibial physeal fractures?

Answer 19

• Cross-pinning from medial and lateral malleoli
• IM pinning or single transarticular pin (talus to tibial medullary cavity) with rigid external coaptation. Less desirable, ONLY if not enough bone for cross pinning

Question 20

What are the repair options of malleolar fractures?

Answer 20

• Pins alone
• Pin and tension band
• Screw

Question 21

List the main forms of congenital/developmental tibial deformities and the breeds most commonly associated with them

Answer 21

• Pes Varus - Dachshunds
• Pes Valgus - Shelties, Large breeds
• Significant increase in TPA - Westies