39. Diseases of the stifle joint. Diseases of the ligaments in stifle joint- LCC and LCCa and collateral ligaments. Diagnosis and treatment.

What are the collateral ligaments of the stifle?

1. lig. collaterale mediale

2. lig. collaterale laterale

What is the primary function of the collateral ligaments in the stifle?

Stabilisation during flexion

What are the cruciate ligaments?

1. lig. cruciatum craniale

2. lig. cruciatum caudale

What is the primary function of the cruciate ligaments in the stifle?

Stabilisation during extension

Into which two functional components is the cranial cruciate ligament divided?

Craniomedial band and caudolateral band

When is the craniomedial band of the CrCL under tension?

During flexion and extension

When is the caudolateral band of the CrCL under tension?

During extension

How does the caudal cruciate ligament differ from the cranial cruciate ligament in its function?

Larger cranial portion under tension during flexion, smaller caudal portion under tension during extension

Which ligament is most commonly ruptured in the stifle?

Cranial cruciate ligament (CrCL)

Which breeds are most commonly affected by CrCL rupture?

Large breeds

What are some proposed aetiologies of CrCL rupture?

Degenerative disorders, patella luxation, trauma, overloading, chronic stress, obesity, breed, age, sex, genetics, conformation

What are the clinical signs of CrCL rupture?

Lameness, effusion, osteoarthritis, muscle atrophy, positive sit test, joint instability

How is CrCL rupture diagnosed?

1. History: Acute: onset of non-weight bearing lameness, or chronic intermittent lameness with sudden lameness.

2. Positive sit test: sits with affected leg extended. It is painful to put in normal flexed position

3. Orthopaedic examination: distant observation, gait assessment, standing & laying palpation

   1. Tibial compression test (tibial tuberosity will move forward when flexing metatarsal)

   2. Cranial drawer test (tibial tuberosity will move forward when moving tibia and femur opposite to each other)

   3. Sit test: positive.

4. X-ray: joint effusion, decrease in size of cranial fat pad (due to joint effusion; fat pad sign), osteophytes (on apex of patella)

How is partial CrCL rupture diagnosed?

CS, fat pad signs & osteophyte on x-ray, negative cranial drawer test

What is a positive sit test?

Affected leg extended when sitting

What are some radiographic findings in CrCL rupture?

Joint effusion, decreased size of cranial fat pad, osteophytes

What are some non-surgical treatments for CrCL rupture?

Hyaluronic acid injection, corticosteroids, NSAIDs, stem cells

What are some surgical techniques for CrCL rupture?

1. Intraarticular stabilisation – m. fascia lata

   1. Replacing CrCL w/ a flap from m. fascia lata, going through medial side of tibia till the middle of tibial plateau then through the centre of the distal femur till lateral femur

2. Extraarticular stabilisation - Suture based techniques:

   1. Fabelo-tibial stabilisation: lateral fabellotibial suture - nylon string through tibial tuberosity and around lateral fabella – mimics CCL function.

3. Osteotomy of tibia – modify the distribution of forces:

   1. Tibial plateau levelling osteotomy (TPLO): corrects the slope of the tibial plateau, preventing the femur from sliding down the plateau and tibial thrust is eliminated.

   2. Tibial tuberosity advancement (TTA): positioning of patellar ligament perpendicular to forces in the joint

What is the goal of CrCL surgery?

To stabilise the stifle joint

What does TPLO stand for?

Tibial Plateau Levelling Osteotomy

What does TTA stand for?

Tibial Tuberosity Advancement

When is the caudal cruciate ligament (CaCL) typically ruptured?

Due to trauma

What are clinical signs of CaCL rupture?

Acute lameness (though rarely causes problems)

How is CaCL rupture diagnosed?

X-ray, caudal drawer test

What are some treatment options for CaCL rupture?

1. Conservative: Reduced exercise, NSAIDs

2. Surgery: suture stabilisation, ligament redirection, popliteal tendon tenodesis

What is the function of the collateral ligaments?

Prevent abduction/adduction of the stifle (stabilisation)

What causes collateral ligament rupture?

Trauma

What are the clinical signs of collateral ligament rupture?

Variable degree of lameness

How is collateral ligament rupture diagnosed?

History, physical exam, palpation (stifle joint must be extended during examination)

1. Valgus stress test: medial collateral ligament rupture

2. Varus stress test: lateral collateral ligament rupture

What are the treatment options for collateral ligament rupture?

Surgical reconstruction with sutures or prosthetic ligament