orthopedic-exam

# Orthopedic Exam ## Overview Systematic orthopedic assessment including lameness quantification, specific joint tests with diagnostic criteria, and breed-based disease prediction. Includes both clinical examination techniques and imaging interpretation guidance. ## When to Use - User presents lameness or orthopedic pathology - User needs specific examination technique interpretation or lameness grading - Keywords: lameness, orthopedic, CCL, cruciate ligament, hip dysplasia, patellar luxation, Ortolani, drawer test, lameness grade, OFA, HD score ## Lameness Grading (AAHA Scale) | Grade | Description | Clinical Significance | |---|---|---| | 0 | No lameness | Normal gait | | 1 | Lameness evident only with exercise | Mild; may detect with trotting | | 2 | Lameness evident at walk and trot | Moderate; consistent weight-bearing abnormality | | 3 | Lameness evident at walk; affected limb partially non-weight-bearing | Moderate-severe; obvious gait abnormality | | 4 | Non-weight-bearing lameness | Severe; complete avoidance of limb use | | 5 | Inability to move limb | Critical; paralysis or complete dysfunction | **Assessment Protocol**: Observe walk/trot on hard surface; note weight distribution, stride length symmetry, pain response; repeat after exercise (fatigue may unmask mild lameness) ## Cranial Cruciate Ligament (CCL) Assessment ### Drawer Test (Anterior Drawer Sign) - **Position**: Dog in lateral recumbency; examiner stabilizes femur above knee with one hand, applies gentle anterior pressure on proximal tibia below knee with other - **Positive test**: Anterior tibial translation relative to femur (1-3 mm movement possible) - **Sensitivity/Specificity**: 70-90% for CCL rupture depending on chronicity and observer experience - **Limitation**: False negatives in partial tears or acute cases with protective muscle tone; false positives in excessive ligamentous laxity ### Tibial Thrust (Cranial Tibial Thrust) - **Position**: Dog standing or in lateral recumbency with knee flexed to 90°; examiner stabilizes femur, applies dorsal pressure at proximal tibia while extending stifle - **Positive test**: Cranial tibial displacement during extension (concurrent with straightening) - **Sensitivity**: 72-98% in CCL-deficient stifles (more sensitive than drawer test in early disease) - **Interpretation**: May be positive with partial tears when drawer test is negative **Diagnostic Approach**: Positive drawer test + positive tibial thrust = highly suggestive CCL rupture; confirm with radiography/MRI ## Hip Dysplasia Assessment ### Ortolani Test - **Position**: Dog supine; hip and knee flexed to 90°; examiner abducts femur gently - **Positive test**: Audible/palpable "click" or "clunk" as femoral head subluxates into acetabulum (indicates underlying dysplasia) - **Sensitivity/Specificity**: 64-82% sensitivity; useful in puppies <6 months; becomes unreliable as fibrosis develops - **Interpretation**: Positive Ortolani suggests hip dysplasia; negative result does not rule out disease ### Distraction Index (radiographic measurement) - **Radiographic assessment** required for definitive diagnosis - **PennHIP method**: Measures femoral head displacement; DI = 0.3-0.5 (normal), >0.7 (dysplastic) - **Laxity threshold**: DI >0.3 suggests increased risk of osteoarthritis ### OFA (Orthopedic Foundation for Animals) Scoring - **Classification**: Normal, borderline, dysplastic (based on radiographic features: remodeling, bone proliferation, subluxation) - **Age**: Radiographs at ≥24 months for certification - **Breed-specific prevalence**: German Shepherd (19%), Labrador retriever (12%), Golden retriever (20%) ## Patellar Luxation Grading (Putnam Scale) | Grade | Description | Clinical Findings | |---|---|---| | I | Intermittent; manual reduction possible; weight-bearing normal | May go undetected clinically; incidental finding | | II | Intermittent; manual reduction or spontaneous; weight-bearing abnormal intermittently | Sporadic lameness; palpable luxation during examination | | III | Permanent; manual reduction difficult; weight-bearing compromised; structural changes present | Chronic lameness; muscle atrophy; secondary OA | | IV | Permanent; manual reduction impossible; severe lameness or non-weight-bearing; marked structural changes | Surgical candidate; significant joint remodeling | **Diagnosis**: Palpation during extension/flexion; ±radiography (assess for trochlear dysplasia, medial angulation); ultrasound if soft tissue damage suspected **Breed Predisposition**: Small breeds (Chihuahua, Pomeranian, Toy Poodle); large breed medial luxation less common ## Common Conditions by Species and Location ### Dogs - Forelimb 1. **Shoulder Osteoarthritis (OA)**: Older dogs; German Shepherd, Labrador predisposed; limited extension; pain on manipulation 2. **Elbow Dysplasia**: Large/giant breeds; medial coronoid process disease (MCPD), osteochondrosis dissecans (OCD), ununited anconeal process (UAP); radiography required 3. **Carpal/Metacarpal Injuries**: Partial tears, ligament sprains; may be career-ending in performance dogs ### Dogs - Hindlimb 1. **Hip Dysplasia**: Large/giant breeds (German Shepherd, Labrador, Golden Retriever); OA secondary; manifests as hindlimb lameness, reluctance to jump, bunny-hopping gait 2. **Cranial Cruciate Ligament (CCL) Rupture**: Common; large breed predisposition; acute grade 3-4 lameness or insidious chronic grade 1-2 3. **Patellar Luxation**: Small breeds primarily; intermittent lameness or persistent non-weight-bearing 4. **Meniscal Tear**: Often concurrent with CCL rupture; secondary to OA progression; medial meniscus most common ### Cats 1. **Hip Dysplasia**: Less common than in dogs; Maine Coons, Persians predisposed; may go undiagnosed (cats compensate well) 2. **Patellar Luxation**: Less common; similar presentation to dogs 3. **Osteoarthritis**: Underdiagnosed; manifests as reduced jumping, reluctance to climb, behavioral changes; not traditional lameness 4. **Fractures**: Falls, trauma; radiography essential ### Horses 1. **Lameness Assessment**: AAEP scale (0 = sound, 5 = non-weight-bearing); joint flexion tests; response to intra-articular anesthesia diagnostic 2. **Suspensory Ligament Injury**: Common in sport horses; ultrasound assessment essential 3. **Navicular Disease**: Chronic forelimb lameness; radiographic changes (demineralization, ossification); associated with deep digital flexor tendon pathology ## OFA Hip Dysplasia Score Interpretation | Score | Meaning | Breeding Recommendation | |---|---|---| | 1-6 | Normal | Excellent candidate for breeding | | 7-12 | Borderline | Consider breeding only if mate scores excellent/good | | 13+ | Dysplastic | Not recommended for breeding | ## Limitations - **Drawer test**: Insensitive in early CCL disease or with protective muscle guarding; serial examinations more reliable than single assessment - **Ortolani test**: Unreliable >6 months of age as fibrosis prevents subluxation; PennHIP method more sensitive in adult dogs - **Palpation**: Limited sensitivity for meniscal tears; MRI required for definitive diagnosis - **Radiographic interpretation**: Subtle early changes may be missed; positioning essential for accurate assessment - **Breed predispositions**: Wide individual variation; screening recommendations vary by breed and organization - **Referral to board-certified surgeon recommended** for: CCL rupture with surgical consideration, multiple joint involvement, fracture management, advanced OA, undiagnosed lameness after clinical/radiographic workup