Luxating patella (Canine) — NAVLE Prep

Quick anchor

Trigger

Intermittent skipping hindlimb lameness

First step

Palpate and grade the patella during orthopedic exam

Clue

Small-breed dog with sudden skip then normal stride

Trap

Do not blame every stifle lameness on patellar luxation

Exam core — read this first

Classic signalment → small-breed dog with intermittent hindlimb skip

Diagnosis → orthopedic palpation and grading are central

Management split → mild incidental cases may be conservative, persistent dysfunction pushes surgery

Board comparison → separate this from cranial cruciate disease and hip disease

Pattern recognition

Core pattern

Toy breedSkipping gaitIntermittent hindlimb lameness

Supporting clues

Often medial luxationNormal between episodesStifle click or palpable displacementYoung dog historyChronic osteoarthritis if longstanding

NAVLE trigger: The “skip a few steps then looks normal again” description is a classic clue.

Decision core — what NAVLE actually asks

Persistent functional lameness or higher-grade luxation

→ Surgical correction becomes more likely to be the expected answer

Comfortable mild intermittent case

→ Weight control, conditioning, and monitoring may be reasonable initially

Painful stifle with effusion or marked instability

→ Re-check for concurrent cranial cruciate disease rather than assuming isolated luxation

Key interpretation

Signalment

Small breed common

High-yield pattern clue

Exam

Patellar palpation

Core diagnostic step

Gait

Skipping / bunny hop

Intermittent mechanical pattern

Grade

Matters

Helps predict management and chronicity

Can develop

Chronic consequence of maltracking

Concurrent CCL

Possible

Do not miss other stifle disease

⚠ A dog can have both patellar luxation and cruciate disease. A painful unstable stifle deserves a full exam, not a shortcut diagnosis.

Treatment

Step 1

Orthopedic exam, grade the luxation, and assess functional impact

That is the foundation for every next step.

Step 2

Conservative management for selected mild comfortable cases

Weight control and conditioning still matter.

Step 3

Surgical realignment for persistent lameness or significant instability

This is the common board answer for clinically important cases.

NAVLE traps — where students lose marks

The classic gait can be intermittent and easy to dismiss

That does not make the diagnosis trivial.

Palpation is central

Radiographs support the case but do not replace the orthopedic exam.

Mild incidental luxation is not the same as functionally important disease

The surgery decision depends on clinical impact.

Painful stifle effusion should trigger CCL thinking too

The exam often hides a second lesion in the same limb.

Differentials — how to separate these on NAVLE

Fast separator: Luxating patella is the intermittent skipping small-dog stifle problem. Compare it with cranial cruciate rupture and hip disease.

Problem	Pattern	Key exam clue	Key separator
Luxating patella	Skipping gait	Patella can be displaced	Intermittent mechanical stifle problem
Cranial cruciate rupture	Persistent lameness	Drawer / tibial thrust	Instability rather than simple skipping
Hip dysplasia	Hip pain / bunny hopping	Hip exam changes	Not a patellar tracking problem
Iliopsoas strain	Soft tissue pain	No luxating patella on palpation	Different orthopedic localization
Neurologic disease	Ataxia / paresis	Abnormal neuro exam	Not purely stifle mechanical

30-second revision

SignalmentToy-breed dog

Classic gaitSkip then normal stride

Core examPatellar palpation and grading

When surgery risesPersistent dysfunction / significant grade

Critical trapDo not miss concurrent CCL disease

Practice questions

Pre-built NAVLE-style · Luxating patella

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Q1Recognition

Which signalment and gait description is most classic for canine luxating patella?

Q2Diagnostic logic

What is the most important core diagnostic maneuver for suspected luxating patella?

Q3Management

Which scenario most strongly pushes canine patellar luxation toward surgical correction?

Q4Differential

Which finding more strongly suggests cranial cruciate rupture than isolated luxating patella?

Q5Trap question

Which statement about luxating patella is most accurate?