Name the 2 cruciate ligaments and the direction they run in

• Cranial

– Runs in same direction as your hand in your pants pocket

– More cranial in the intercondylar space

– Runs cranially & medially as it courses distally to insert at the cranial intercondyloid area of the tibia

• Caudal

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What are the 3 functions of the CrCL

• 1. prevent cranial displacement of the tibia

• 2. limit internal tibial rotation

• 3. prevent stifle hyperextension

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What are the 2 distinct bands of the CrCL & their functions

• Craniomedial band

– Taut during flexion AND extension

• I.e. always working

– This rupture only drawer in flexion

• Caudolateral band

– Only taut in extension

– Rupture = no cranial drawer

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What causes CrCL rupture

• Excess stress on normal ligament

– Uncommon in dogs

• Normal stress on abnormal lig

– Most common form in dogs

– Degeneration occurs earlier & is more severe in larger breeds

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What might you find on PE - acute rupture

• Acute rupture

– Lameness

– Effusion

– Often not super painful

– Cranial drawer sign

• Complete rupture present in flex & extension

• Only craniomedial band = drawer in flex

• Only caudolateral = no cranial drawer

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What might you find on PE - chronic rupture

• Lamenss

• Muscle atripohy

• Periarticular fibrosis

• Joint effusion

• +/- crepitus

• Decreased ROM

• +/- cranial drawer

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What is the gold Dx test for cruciate rupture?

• Cranial drawer!

• Why is it commonly missed? – Diff to detect in conscious pt

– Need good technique

– Periarticualr fibrosis may limit cranial drawer

– Might only be partially ruptured (i.e. caudolateral band tear = no drawer)

– Absence doesn’t rule out cruciate disease!

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What can you see?

Displaced fat pad because joint effusion

Osteophyts on distal pole of patella

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What might you see on rads?

- Bone sclerosis

- Osteophytes on , distal pole of patella trochlear ridge, tibial plateau

- Look for avulsion fractures

- Joint effusion – displacement of fat pad

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What are some options for treating cruciate disease?

• Conservative – NO! continued instability – worsening!

• Sx – Passive joint stabilisation

• Extracapsular – Lateral fabello-tibial suture

• Intracapsuar – not used anymore

– Tibial osteotomy sx • TPLO ~4% late meniscal injury

• TTO ~4%

• TTA – 22-42% late meniscal injury!

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Describe skin incision for stifle joint exploration & cruciate sx

• Curvilinear skin incision centred at level of patella, on lateral aspect of stifle

• Extend from distal 1/3- ½ of femurs

• Down to a point just distal to tibial tuberosity

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Now what?

• Incise SQ tissue along same line of skin incision –

• Fascia lata & lateral reticulum are incised along similar line – approx 2-3mm caudal to patella lig, incise fascia 15mm lateral to patella lig (leave enough tissue between incison & patella to place sutures alter

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After incising fascia lata(remember that really

plasticcy kind of tissue that the biceps is attached to)

• Fascia lata is undermined & reflected caudally

– Beware: the peroneal nerve

• Proximally – need to dissect the loose fascia between the biceps & vastus lateralis and the facial attachment of the vastus to the femur

– In this way we can reflect biceps – expose and locate lateral fabella – before making capsule incision

– To expose the joint capsule

– Beware: avoid the caudal femoral a & v in this area

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Once the joint capsule is exposed

• Make a stab incision at the level of the patella

– Along the same line as the precious incisions

• Extend this incision in the capsule distally to level of the tibia – don’t damage the long digital extensor tendon

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So how to we maximise our visibility into the joint?

• Extend the joint, luxate patella medially then flex joint to hold patella out of the way

• Use gelpi retractor in soft tissue to aid exposure

• Retract infrapatella fat pad cranially with sharp pointed Senn retractor – ID sites of stifle distractors

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ID sites of stifle distractors

• Intracondylar fossa of the femur & the insertion site of the cr cruciate lig of the tibia

• When stifle distractors are openend the distal point will hook on intermeniscal lig behind the fat pad

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• ID origin & insertion of both long digital extensor tendon (lateral femoral condyle) and the lateral collateral lig

• ID Cr & Cau crucitae lig

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How to visualise the menisci?

• Put the stifle in cranial drawer –

• Use either

– Stifle joint distractor

– OR Homann retract with a Senn retractor

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Which meniscus is more likely to be damaged?

• Medial – because

– Firmly attached to tibial plasteau

– Lateral meniscus is only loosely attached – able to move out of the way

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How to place LFTS? – which muscles to retract/elevate?

• Reflect biceps femoris – caudally at level of patella – use sharp/blunt dissection

• Need to be able to visualise the lateral fabella

– (which is at the same level of the patella, in the origin if the lateral head of

the gastrocnemius)

• Elevate the cranial tibial muscle – from the prox lateral tibia

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Where do we drill the hole?

• Subperiosteally elevate cr tibial muscle from prox lateral tibia – allow placement of the hole

• Transversely through the prox tibia, at the level of the tibial tuberosity

• Use drill bit & Jacob's chuck/power drill

• Tunnel needs to be perpendicular to the bone (lateral to medial)

• Mark location of hole using a 18g needle

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Now we have a hole…?

• Pass cruciate needle around the lateral sesamoid – Beware trapping the peroneal n. – immediately caudal to fibula head!!! – Feed the needle cranioprox to caudal distally – Walk needle tip off the bone to stay as close as possible to the fabella – Once placed – tugging on suture should feel fabella moving (about 1mm)

• Place distal end of suture through the tunnel, then feed suture back behind the patella lig

– Tie/crimp it securely adjacent to the lateral part of femoral condyle – Tied in a neutral standing position – Place knot on laterla aspect of the stifle so you can suture biceps over the top

of it to hide the knot

– ***use 27 or 36kg nylon leader line

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closing

• Close the fascia lata with an interrupted pattern to achieve imbrication

– Caudal edge of fascia should imbricate over the top of the cranial edge – horizontal mattress sutures

– Close SQ and skin

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