SA Musculoskeletal Conditions of Tibia and Tarsus

Question 1

1. Aetiology of premature closure of the caudal proximal tibial physis?
2. Pathogenesis of premature closure of caudal proximal tibial physis?
3. Tx for premature closure of the caudal proximal tibial physis?

Answer 1

1. Physeal fracture leading to the premature fusion of the physis.
2. Continued growth of cranial aspect of proximal tibia results in alteration of tibial plateau angle, and potential to lead to rupture of CCL or degenerative joint disease.
3. Tibial osteotomy to correct the abnormal tibial plateau and subsequent CCL rupture.

Question 2

1. Aetiology of premature closure of the distal tibial physis.
2. How does this look on radiograph?
3. Signalment?
4. Tx for premature closure of distal tibial physis?

Answer 2

1. Hereditary.
2. Bilateral angular deformity.
3. Immature / young adult (6-7mths).
   Shelties (tarsal valgus).
   Dachshunds (tarsal varus).
4. Osteotomy and ESF or plate.
   Physeal staple in immature dog?
   - on overgrowing side to stop growth in hopes will self-correct.

Question 3

1. Tibial tuberosity avulsion fracture aetiology.
2. Signalment for tibial tuberosity avulsion fracture.
3. Dx of tibial tuberosity avulsion fracture?
4. Tx of tibial tuberosity avulsion fracture?

Answer 3

1. Fall or jump, intrinsic force/muscle contraction (quads).
2. Terriers (SBT) 3-5mths.
3. Radiography, both sides to compare.
4. Pins and TBW.
   Px usually good.

Question 4

Options for tx of tibial diaphyseal fractures…
1. external coaptation.
2. IM pinning.
3. interlocking nail.
4. plate and screws / plate and pin.
5. ESF.

Answer 4

1. Can be suitable for simple, stable fractures in young animals w/ intact fibula.
2. Normograde. Tibia narrows distally so size of pin limited. Care w/ length distally (hock) and proximally (stifle). Combine w/ another implant e.g. ESF, plate.
3. Can be used for proximal / mid diaphyseal fractures, size limited by distal bone IM canal.
4. Common repair option - plate applied to medial tibia (less ST so easier surgical approach).
5. Useful for simple fractures in young dogs and cats and for open/comminuted fracture.

Question 5

Why are distal tibial diaphyseal fractures so difficult?

Answer 5

Small - fragments tend to be small and difficult to get implants in. Distal tibia slow to heal in cats (not much ST surrounding).
Double plate best for cats.
- one plate medially and one plate cranially.
– allows to maximise screw number in small distal fragment.

Question 6

1. Distal tibial growth plate fracture aetiology?
2. Signalment for distal tibial growth plate fracture?
3. Dx of distal tibial growth plate fracture?
4. Tx for distal tibial growth plate fracture?

Answer 6

1. Trauma.
2. Dogs and cats <9mths.
3. Tends to be Salter-Harris type I/II.
4. Physeal fracture principles.
   Open reduction and internal fixation if displaced.
   - cast usually needed following stabilisation (initial few weeks).
   External coaptation of minimal displacement (cast).
   Use small cross pins.
   - avoid pin going into joint.

Question 7

Conditions (DIM) of tarsal joint.

Answer 7

Dislocation - traumatic.
Inflammation/infection - tarsal osteochondrosis.
Musculotendinous and ligamentous:
- ruptured plantar ligaments.
- lateral displacement of SDFT.
- rupture or partial rupture of Achilles tendon complex.

Question 8

Anatomy of the tarsus.

Answer 8

Tarsocrural joint.
Talus in contact w/ tibia.
Calcaneus behind talus - Achilles tendon insertion.
Talocentral joint and calcaneoquartal joint = proximal intertarsal joint.
Small tarsal bones 1,2,3,4.
Tarsometatarsal joint.
Metatarsals.

Question 9

1. Dislocation of the hock in the cat aetiology.
2. Dislocation of the hock in the cat pathogenesis.
3. Dislocation of the hock in the cat tx.

Answer 9

1. Usually traumatic injury.
2. Collateral ligament ruptures and/or avulsion fractures of medial malleoli / distal fibular.
   Can be open or closed.
3. Closed - need surgical repair of injured structures and external coaptation / TESF.
   – replacement of ligaments using suture prostheses
   Open - manage wounds.
   – pack w/ gel, clip hair surrounding, flush with saline, debridement, wet-to-dry dressing, bandages and bandage changes until definitive treatment possible.
   - reduction and ESF.

Question 10

Dx of tarsal luxation.

Answer 10

Palpation (collateral ligaments).
- varus and valgus positioning on examination.
Observation - open wounds.
Imaging - radiography/CT.

Question 11

1. Tarsal osteochondrosis pathogenesis?
2. Signalment of tarsal osteochondrosis.
3. Clinical signs of tarsal osteochondrosis.

Answer 11

1. Lesion medial (or lateral) talar ridge.
   Genetic but maybe a traumatic trigger.
2. Rottweilers, Labradors etc.
   5-10mths old.
3. Tarsal swelling.
   Upright hock.
   Lameness.
   Reduced ROM in hock.

Question 12

Dx of tarsal osteochondrosis.

Answer 12

Radiography/CT.
- craniocaudal view most useful.
- lesion on medial 9or lateral talar ridge).
– flattening.
- difficult to dx on lateral talar ridge as superimposition of calcaneus.
– CT better.

Question 13

1. Tx of tarsal osteochondrosis?
2. Px of tarsal osteochondrosis?

Answer 13

1. Conservative:
   - restricted exercise / NSAIDs.
   Surgical:
   -debridement.
2. Guarded - develop OA.

Question 14

1. Aetiology rupture of plantar tarsal ligaments and fibrocartilage.
2. Pathogenesis of rupture of plantar tarsal ligaments and fibrocartilage.
3. Clinical signs of rupture of plantar tarsal ligaments and fibrocartilage.

Answer 14

1. Degenerative (Shelties and Collies) (can be bilateral) or traumatic rupture.
2. Subluxation of proximal intertarsal joint (between talus & calcaneus and first row of tarsal bones).
3. Lameness, plantigrade stance, exercise intolerance, can be bilateral changes.

Question 15

Dx and Tx of rupture of plantar tarsal ligaments and fibrocartilage.

Answer 15

Dx:
- stressed radiographs.
Tx:
- arthrodesis w/ lateral bone plate.

Question 16

Lateral displacement of SDFT.

Answer 16

Palpably displacing tendon (laterally) (clicks).
Shelties.
Lameness / altered gait.
Tx - surgically repair torn retinaculum.
Px usually good.

Question 17

1. Rupture of gastrocnemius aetiopathogenesis?
2. Clinical signs?
3. Signalment?

Answer 17

1. Trauma or degeneration.
   Partial or complete (signs similar).
   Elongation of tendon
   ‘Claw foot’ as SDFT travels longer distance and under tension.
2. Lameness.
   Thickened tendon.
   Claw foot.
   Plantigrade stance.
3. Dobermans, older Labradors, cats.

Question 18

Tx of ruptured gastrocnemius?

Answer 18

Partial rupture - extend hock (e.g. calcaneotibial screw) for 6w to take tension off tendon whilst healing.
- protect w/ cast.
Complete rupture - (tenectomy) and suture.
Avulsion fracture - tx depends on size of avulsed fragment.
– small = excise fragment and ts tendon rupture.
– large = tx as avulsion fracture = pins and TBW.
(pantarsal arthrodesis - salvage sx).