Hip Osteoarthritis Assessment
Hip OA examination combines functional assessment with joint-specific testing. Examiners expect you to assess gait (Trendelenburg), measure ROM accurately, recognize the pattern of restriction (capsular pattern: IR > extension > abduction > flexion), and correlate findings with severity and functional impact.
Quick Reference One-Pager
Cardinal Features
- Groin pain (mechanical)
- Stiffness (especially morning, under 30 min)
- Reduced ROM (capsular pattern)
- Trendelenburg gait
- Fixed flexion deformity (FFD)
ROM Pattern
- Capsular pattern: IR most limited first
- Then extension (FFD develops)
- Then abduction
- Flexion least affected initially
- Compare with opposite side
Functional Assessment
- Gait and walking distance
- Stairs, sitting, standing
- Putting on shoes/socks
- Getting in/out of car
- Night pain, rest pain
Examination Sequence
- Observe gait (antalgic, Trendelenburg)
- Assess leg length
- Measure ROM systematically
- Thomas test for FFD
- Neurovascular check
Clinical Presentation
History Features
Pain Pattern:
- Groin pain (commonest site)
- May radiate to anterior thigh, knee (referred)
- Lateral hip (if associated trochanteric bursitis)
- Mechanical: worse with activity, better with rest
- Start-up pain (stiffness on rising)
- Night pain indicates severe disease
Stiffness:
- Morning stiffness less than 30 minutes (OA pattern)
- Greater than 30 minutes suggests inflammatory arthritis
- Improving with movement
Functional Impact:
- Walking distance reducing
- Stairs difficult (especially descending)
- Difficulty with socks/shoes
- Getting in/out of car
- Sexual function may be affected
Gait Assessment
Gait Patterns in Hip OA
Antalgic Gait:
- Short stance phase on affected side
- Patient "gets off" the painful hip quickly
- Indicates pain as primary driver
Trendelenburg Gait:
- Pelvis drops on swing (unaffected) side
- Indicates abductor weakness (gluteus medius)
- May be due to pain inhibition or muscle wasting
Compensated Trendelenburg:
- Trunk shifts OVER affected hip
- Moves center of mass over hip
- Reduces force required from abductors
Combined Pattern:
- Most hip OA patients have both antalgic and Trendelenburg components
- The combined pattern is diagnostic of hip pathology
Special test
Trendelenburg Test
Hip abductor function
Technique
- 1Patient stands facing examiner
- 2Ask patient to stand on one leg (affected side)
- 3Observe pelvis from behind for 30 seconds
- 4Repeat on opposite side for comparison
Positive Sign
Pelvis drops on the unsupported (swing) side
Indicates
Hip abductor weakness (gluteus medius dysfunction) - OA, post-THR, L5 weakness, DDH
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Range of Motion Assessment
Systematic ROM Testing
Capsular Pattern (OA): Internal rotation > Extension > Abduction > Flexion
This means IR is lost first and most severely, while flexion is preserved longest.
Normal Values:
- Flexion: 120-130°
- Extension: 10-15° (beyond neutral)
- Abduction: 45-50°
- Adduction: 20-30°
- Internal rotation: 35-45°
- External rotation: 45-50°
Testing Position:
- Flexion: Supine, stabilize pelvis
- Extension: Thomas test (supine) or prone
- Abduction: Supine, stabilize pelvis
- Rotation: Supine with hip flexed 90° or with hip extended
Special test
Thomas Test
Fixed flexion deformity assessment
Technique
- 1Patient supine
- 2Flex opposite hip fully to flatten lumbar lordosis
- 3Pelvis stabilized by full flexion of unaffected hip
- 4Observe affected leg
Positive Sign
Affected hip cannot rest flat on bed (flexion deformity)
Indicates
Fixed flexion deformity - measure angle between thigh and bed. FFD indicates hip OA, capsular contracture
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Fixed Flexion Deformity (FFD):
- Develops as OA progresses
- Compensated by lumbar hyperlordosis when standing
- Causes increased energy expenditure in gait
- Contributes to apparent leg length discrepancy
- Target for surgical correction in THR
Leg Length Assessment
Leg Length Discrepancy
True vs Apparent:
- True LLD: Measure ASIS to medial malleolus (bony length)
- Apparent LLD: Measure umbilicus/xiphisternum to medial malleolus (functional)
- Apparent greater than true = adduction deformity or pelvic obliquity
Causes of LLD in Hip OA:
- True shortening: Superior migration of femoral head, femoral head collapse (AVN, OA)
- Apparent shortening: Fixed adduction deformity
- Apparent lengthening: Fixed abduction deformity
Galeazzi Test (Bryant Test):
- Patient supine, hips and knees flexed, feet flat on bed
- Observe knee heights
- Unequal knee height indicates tibia or femur discrepancy
Functional Tests
Special test
Sit-to-Stand Test
Functional hip assessment
Technique
- 1Patient sits in standard chair (45cm height)
- 2Ask patient to stand up without using arms
- 3Observe ability and any compensation
Positive Sign
Difficulty rising, using arms to push up, trunk lean
Indicates
Hip weakness, pain, or stiffness
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Six-Meter Walk Test
Functional mobility
Technique
- 1Mark 6-meter distance
- 2Time patient walking at comfortable pace
- 3Note gait abnormalities, aid use
Positive Sign
Slow walking speed (under 1 m/s suggests significant impairment)
Indicates
Functional limitation - correlates with surgical outcomes
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Special test
Shoe Test
Functional hip ROM assessment
Technique
- 1Ask patient to put on shoes and socks (or demonstrate)
- 2Observe method used
Positive Sign
Unable to reach foot, needs assistance or devices
Indicates
Significant hip stiffness affecting daily function
Diagnostic Accuracy
Ability to detect true positives
Ability to exclude false positives
Severity Assessment
- pain
- Activity-related, walking unlimited
- rom
- Mild restriction (IR mainly)
- function
- Minor limitation
- xray
- Joint space greater than 2mm
- pain
- After shorter walks, some rest pain
- rom
- Moderate restriction, developing FFD
- function
- Significant limitation
- xray
- Joint space 1-2mm
- pain
- Night pain, rest pain, very limited walking
- rom
- Severe restriction, FFD greater than 15°
- function
- Major ADL impairment
- xray
- Bone on bone
Differential Diagnosis
- painLocation
- Groin, anterior thigh
- rom
- Capsular pattern
- specialFeatures
- Mechanical pain, morning stiffness under 30 min
- painLocation
- Back to buttock, below knee
- rom
- Hip ROM normal
- specialFeatures
- Neurological signs, SLR positive
- painLocation
- Lateral hip
- rom
- Normal (may resist abduction)
- specialFeatures
- Point tenderness over GT
- painLocation
- Groin (severe)
- rom
- May be normal early
- specialFeatures
- Risk factors, night pain early
- painLocation
- Groin
- rom
- Polyarticular often
- specialFeatures
- Morning stiffness greater than 30 min, systemic features
- painLocation
- Groin
- rom
- IR limited, others preserved
- specialFeatures
- Young patient, FADIR positive
Imaging Correlation
Kellgren-Lawrence Grading (X-ray)
- Findings
- Normal
- Findings
- Doubtful: possible osteophytic lipping
- Findings
- Minimal: definite osteophytes, possible JSN
- Findings
- Moderate: Moderate JSN, some sclerosis, cyst formation
- Findings
- Severe: Large osteophytes, marked JSN, severe sclerosis, bone deformity
Note: Clinical severity may not correlate with radiographic severity
Preoperative Assessment for THR
What Examiners Want
Document for THR planning:
- Walking distance (how far before stopping)
- Night pain, rest pain
- Analgesic use (type, frequency)
- Failed conservative treatments
- ROM restrictions (especially FFD)
- Leg length discrepancy
- Trendelenburg status
- Medical fitness (ASA grade)
- Patient expectations
Summary Presentation
“68-year-old woman with 3-year history of progressively worsening right hip pain. Now using a walking stick and can only walk 100 meters.”
Outcome Measures
Patient-Reported Outcomes
Harris Hip Score (HHS):
- Maximum 100 points
- Pain (44), Function (47), ROM (5), Deformity (4)
- Under 70 poor, 70-79 fair, 80-89 good, 90-100 excellent
Oxford Hip Score (OHS):
- 12 questions, patient-completed
- Scores 0-48 (higher = better)
- Widely used in registries (AOANJRR)
WOMAC:
- 24 questions: Pain (5), Stiffness (2), Function (17)
- Validated for hip and knee OA
Examiner Tips
Do
- Observe gait first (antalgic, Trendelenburg)
- Measure ROM systematically (document degrees)
- Perform Thomas test for FFD
- Assess true and apparent leg length
- Document functional impact (walking distance)
Don't
- Forget to compare with opposite side
- Miss the capsular pattern of restriction
- Skip Thomas test
- Ignore lumbar spine as differential
- Forget neurovascular assessment