Ruptured cranial cruciate ligament (Canine) — NAVLE Prep

Quick anchor

Trigger

Hindlimb lameness with painful effused stifle

First step

Check cranial drawer and tibial thrust

Remember

Meniscal injury can coexist

Trap

Hip pain does not create positive stifle instability tests

Exam core — read this first

Classic lesion → stifle instability from partial or complete cranial cruciate rupture

Best exam clues → joint effusion, cranial drawer, tibial thrust, medial buttress chronically

Board management → many clinically significant canine cases push toward surgical stabilization

High-yield overlap → meniscal injury commonly complicates the case

Pattern recognition

Core pattern

Hindlimb lamenessPainful stifle effusionInstability on exam

Supporting clues

Large- or medium-breed dogAcute non-weight-bearing or chronic worsening lamenessMedial buttress if chronicSits abnormallyMeniscal click possible

NAVLE trigger: Positive drawer or tibial thrust is the fastest high-yield separator from many other orthopedic problems.

Decision core — what NAVLE actually asks

Stifle instability confirmed

→ Treat as a cruciate disease case rather than vague hindlimb lameness

Clinically important canine CrCL rupture

→ Surgical stabilization is commonly the expected definitive answer

Persistent pain or mechanical clicking

→ Meniscal injury should stay high on the list

Key interpretation

Cranial drawer

High yield

Core instability test

Tibial thrust

Also key

Especially useful if drawer is subtle

Effusion

Common

Supports active stifle disease

Radiographs

Supportive

Effusion/OA changes, but instability exam is central

Meniscal injury

Important

Persistent pain/clicking clue

Chronic change

Medial buttress

Classic long-standing sign

⚠ A painful hindlimb is not enough. NAVLE usually wants you to identify the unstable stifle specifically.

Treatment

Step 1

Confirm instability and control pain / restrict activity

The patient needs orthopedic stabilization planning.

Step 2

Definitive surgical stabilization in most clinically significant canine cases

This is the usual board-level answer for dogs with functional instability.

Step 3

Rehabilitation, weight control, and OA management

Even after surgery, long-term stifle care matters.

NAVLE traps — where students lose marks

Do not call every hindlimb lameness “hip disease”

Positive drawer/tibial thrust localizes to the stifle.

Partial tears still create pain and effusion

The exam may not give you a dramatic complete rupture history.

Meniscal injury changes recovery and persistence of pain

That is a classic follow-on clue.

Patellar luxation and cruciate disease can coexist

A convenient small-dog diagnosis should not end the exam.

Differentials — how to separate these on NAVLE

Fast separator: CrCL rupture is an unstable painful stifle. Compare it with luxating patella, hip dysplasia, and iliopsoas injury.

Problem	Pain pattern	Key exam clue	Key separator
CrCL rupture	Stifle pain/lameness	Drawer / tibial thrust	Instability disease
Luxating patella	Often intermittent	Patella displacement / grade	Skipping gait more classic
Hip dysplasia	Hip-origin pain	Hip exam findings	No positive drawer
Iliopsoas strain	Muscle pain	No stifle instability	Soft tissue not intra-articular
Neurologic paresis	Weakness/ataxia	Abnormal neuro exam	Not isolated stifle instability

30-second revision

LocalizePainful unstable stifle

Best testsDrawer and tibial thrust

Common definitive careSurgical stabilization

Complication clueMeniscal injury

Critical trapHip disease does not cause positive drawer

Practice questions

Pre-built NAVLE-style · Ruptured cranial cruciate ligament

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Q1Recognition

Which finding most strongly supports canine cranial cruciate ligament rupture?

Q2Management

What is the most typical definitive-management concept for clinically significant canine CrCL rupture?

Q3Differential

Which description is more classic for luxating patella than CrCL rupture?

Q4Complication

What important associated problem should remain on your list in a painful CrCL case?

Q5Trap question

Which statement about canine CrCL rupture is most accurate?