Tier 1 — must know
Canine
Musculoskeletal / Nervous
High yield
Ruptured cranial cruciate ligament
Common canine stifle emergency/orthopedic topic · drawer/tibial thrust reasoning · surgery-heavy board logic
⏱ 2–3 min read · Topic 23 of 33
5
Practice Qs
4
Traps
High
Exam freq.
—
Your status
Study step
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
Clinical mechanism — only what matters
CrCL failure → permits abnormal cranial tibial translation
Instability → creates pain, synovitis, and progressive osteoarthritis
Meniscal stress → secondary meniscal damage can worsen pain and recovery
The exam asks whether you recognize the unstable stifle and distinguish it from other hindlimb lameness causes.
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 |
Clinical application tools
These provide general support only; the diagnosis still rests on orthopedic localization and instability testing.
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
0 / 0
Which finding most strongly supports canine cranial cruciate ligament rupture?
What is the most typical definitive-management concept for clinically significant canine CrCL rupture?
Which description is more classic for luxating patella than CrCL rupture?
What important associated problem should remain on your list in a painful CrCL case?
Which statement about canine CrCL rupture is most accurate?