Orthopedic Exam

---
name: orthopedic-exam
description: Lameness grading (AAHA scale), joint assessment (drawer sign/tibial thrust for CCL, Ortolani for hip dysplasia), patellar luxation grading I-IV, OFA scoring, breed predispositions, common conditions by species.
---

# 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