Joint Space Narrowing | Conservative First | THA When Failed
KELLGREN-LAWRENCE GRADING
Critical Must-Knows
- Groin pain with activity is classic presentation
- Radiographs: JSN, osteophytes, sclerosis, cysts
- Conservative FIRST: weight loss, PT, NSAIDs, injections
- THA when conservative fails and quality of life impaired
- Primary OA most common; secondary includes AVN, DDH, FAI
Clinical Pearls
- "Internal rotation first motion lost
- "AP pelvis + lateral of affected hip for imaging
- "Young patients consider hip preservation before THA
- "Avoid THA in active infection, poor health that precludes surgery
Clinical Imaging
Imaging Gallery
Critical Exam Concepts
Groin Pain
True hip pathology causes GROIN pain. Lateral hip pain is often trochanteric bursitis. Buttock pain may be referred from spine.
Conservative First
Always trial conservative measures before THA. Weight loss, physiotherapy, walking aids, NSAIDs, injections. Surgery for failed conservative.
Radiograph Findings
Classic X-ray changes: Joint space narrowing, osteophytes, subchondral sclerosis, subchondral cysts. LOSS is mnemonic.
Young Patients
Consider hip preservation first in young patients - osteotomy, arthroscopy for FAI/labral tears. THA means revision surgery in future.
Hip OA vs Other Hip Conditions
| Condition | Pain Location | Key Feature | Imaging |
|---|---|---|---|
| Hip OA | Groin | Activity-related, stiffness | JSN, osteophytes |
| Trochanteric bursitis | Lateral | Point tenderness GT | Normal or bursitis |
| AVN | Groin | Risk factors (steroids, alcohol) | Crescent sign, collapse |
| Labral tear | Groin, clicking | Younger, mechanical symptoms | MRA shows tear |
LOSSOA X-ray Findings
| L | Loss of joint space Narrowing, bone-on-bone |
| O | Osteophytes Bone spurs at margins |
| S | Subchondral sclerosis Dense bone under cartilage |
| S | Subchondral cysts Geodes in bone |
| L | Loss of joint space Narrowing, bone-on-bone | S | Subchondral sclerosis Dense bone under cartilage |
| O | Osteophytes Bone spurs at margins | S | Subchondral cysts Geodes in bone |
Hook:LOSS of cartilage causes all these changes!
DAFTSecondary OA Causes
| D | DDH Developmental dysplasia of hip |
| A | AVN Avascular necrosis |
| F | FAI Femoroacetabular impingement |
| T | Trauma Post-traumatic OA |
| D | DDH Developmental dysplasia of hip | F | FAI Femoroacetabular impingement |
| A | AVN Avascular necrosis | T | Trauma Post-traumatic OA |
Hook:DAFT causes lead to secondary OA!
WIPEConservative Treatment
| W | Weight loss Reduces joint loading |
| I | Injections Steroid or hyaluronic acid |
| P | Physiotherapy Muscle strengthening, ROM |
| E | Exercise and NSAIDs Low impact, anti-inflammatories |
| W | Weight loss Reduces joint loading | P | Physiotherapy Muscle strengthening, ROM |
| I | Injections Steroid or hyaluronic acid | E | Exercise and NSAIDs Low impact, anti-inflammatories |
Hook:WIPE out the pain with conservative treatment!
Overview and Epidemiology
Primary vs Secondary OA
Primary OA = no identifiable cause (wear and tear). Secondary OA = underlying condition (DDH, AVN, FAI, trauma, inflammatory arthritis). Secondary OA often affects younger patients.
Epidemiology
- 10% of adults over 60
- Increases with age
- More symptomatic in females
- Obesity major risk factor
- Leading indication for THA
Risk Factors
- Age: Primary risk factor
- Obesity: Increased joint loading
- Genetics: Strong family history component
- Occupation: Heavy labor
- Prior pathology: DDH, Perthes, SCFE, FAI
Pathophysiology and Anatomy
Hip Joint Anatomy
Ball and socket: Femoral head articulates with acetabulum.
Articular cartilage: Hyaline cartilage covers both surfaces. 3-4mm thick.
Labrum: Fibrocartilaginous rim deepens socket by 22%.
Capsule: Strong, reinforced by iliofemoral, pubofemoral, ischiofemoral ligaments.
Blood supply: MFCA (primary to head), LFCA, artery of ligamentum teres.
Rule Out Secondary Causes
In younger patients (under 50) with hip OA, always consider secondary causes - DDH, AVN, FAI, SCFE sequelae. These affect treatment planning and prognosis.
Classification Systems
Kellgren-Lawrence Grading
| Grade | Description | Clinical Correlation |
|---|---|---|
| 0 | No features of OA | Normal |
| 1 | Doubtful JSN, possible osteophytes | May be asymptomatic |
| 2 | Definite osteophytes, possible JSN | Mild symptoms |
| 3 | Moderate osteophytes, definite JSN, some sclerosis | Moderate symptoms |
| 4 | Large osteophytes, marked JSN, severe sclerosis, cysts | Severe, THA candidate |
Widely used, good inter-observer reliability for extremes.
Clinical Assessment
History
- Pain: Groin (true hip), activity-related
- Stiffness: Morning, improves with movement
- Function: Walking distance, stairs, ADLs
- Night pain: Advanced disease
- Impact on QoL: Work, recreation, sleep
Examination
- Gait: Antalgic, Trendelenburg
- ROM: Internal rotation lost first
- FABER/FADIR: Provoke pain
- Leg length: May be shortened
- Trendelenburg: Abductor weakness
Internal Rotation First
Internal rotation is the first motion lost in hip OA and often the most painful. Check ROM with patient supine and hip at 90 degrees flexion for accurate assessment.
Outcome Measures
Harris Hip Score: Classic outcome measure. Pain, function, ROM, deformity.
Oxford Hip Score: Patient-reported, 12 questions. Widely used.
HOOS: Hip Disability and Osteoarthritis Outcome Score. Comprehensive.
Investigations
Plain Radiographs
Views:
- AP pelvis (weight-bearing if possible)
- Lateral of affected hip (cross-table or frog-leg)
Findings (LOSS):
- Loss of joint space
- Osteophytes
- Subchondral sclerosis
- Subchondral cysts
May underestimate cartilage loss compared to MRI.
Weight-Bearing Films
Weight-bearing AP pelvis shows true joint space narrowing. Non-weight-bearing films may overestimate cartilage thickness. Always try to obtain weight-bearing views.
Management Algorithm
Hip OA Treatment Algorithm
Management Pathway
Clinical history and examination. Radiographs. Rule out secondary causes.
Weight loss, exercise, PT, NSAIDs, walking aids. Trial injections if needed.
If quality of life significantly impaired despite conservative measures, consider surgery.
THA (most common). Consider preservation surgery in young if appropriate.
Surgical Considerations
Indications for THA
Appropriate:
- Failed conservative treatment
- Significant functional impairment
- Pain affecting quality of life
- Radiographic evidence of OA
Relative contraindications:
- Active infection
- Poor health precluding surgery
- Unrealistic expectations
- Neuropathic joint (Charcot)
Age alone is not a contraindication.
Young Patient Counseling
Young patients (under 50) undergoing THA must be counseled about revision surgery probability. Current implants may last 20+ years but revision is likely within their lifetime.
Complications
| Complication | Conservative | THA |
|---|---|---|
| GI bleeding | NSAIDs risk | N/A |
| Infection | N/A | 1% (PJI) |
| Dislocation | N/A | 1-3% |
| DVT/PE | N/A | Despite prophylaxis |
| Leg length discrepancy | N/A | Measured and addressed |
| Loosening | N/A | Long-term, leads to revision |
Conservative Treatment Risks
NSAIDs have significant risks: GI bleeding, renal impairment, cardiovascular events. Use lowest dose for shortest time. Consider PPI cover. Acetaminophen is safer for chronic use.
Postoperative Care (THA)
THA Recovery
Mobilize day of surgery. DVT prophylaxis. Pain control. Precautions if posterior approach.
Discharge home 1-3 days. PT, gait aids. Wound care. Continue DVT prophylaxis.
Increase mobility. Wean walking aids. Drive when safe. Return to desk work.
Most return to pre-morbid activities. Low-impact sport allowed. Full function.
Dislocation Precautions
Posterior approach precautions: Avoid hip flexion greater than 90 degrees, internal rotation, adduction past midline. Duration varies (6-12 weeks). Anterior approach may have fewer precautions.
Outcomes and Prognosis
THA Outcomes
Survival: 95%+ at 15 years in correctly selected patients.
Function: Dramatic pain relief and functional improvement.
Satisfaction: Over 90% satisfied.
Revision risk: Higher in young, active patients. Polyethylene wear, loosening, infection main causes.
Non-Operative Outcomes
Natural history: Progressive deterioration. Rate varies.
Conservative treatment: Symptom management. Does not alter disease progression.
Controversies and Areas of Uncertainty
Repeated Steroid Injections
The McAlindon JAMA trial showed scheduled intra-articular triamcinolone caused greater cartilage loss with no durable pain benefit (in the knee). Whether repeated hip injections accelerate joint failure or compromise later arthroplasty remains debated; most now reserve injection for short-term flare relief or diagnosis.
Optimal Timing of THA
PROHIP confirms THA outperforms exercise once a surgical indication exists, but around 1 in 5 patients improve enough with exercise to defer surgery. Defining the "tipping point" - and avoiding both premature and unduly delayed surgery - is unresolved.
Surgical Approach
Direct anterior versus posterior approach remains contested: anterior may speed early recovery but carries a learning curve and lateral femoral cutaneous nerve risk. Registry data show approach matters less than surgeon volume and experience.
Hip Preservation vs Early Arthroplasty
In young dysplastic or FAI hips, the threshold of remaining cartilage at which PAO or arthroscopy still works (versus proceeding to THA) is uncertain; established radiographic OA predicts PAO failure.
Disease-Modifying Drugs
There is no proven disease-modifying drug for hip OA. Glucosamine, chondroitin and hyaluronic acid injection lack convincing evidence in the hip (ACR strongly recommends against hip viscosupplementation). All current treatment is symptomatic or surgical.
Evidence Base and Key Studies
PROHIP: Total Hip Replacement vs Resistance Training for Severe Hip OA
- Multicentre RCT, 109 patients aged 50+ with severe hip OA and a surgical indication
- Oxford Hip Score improved 15.9 points with THA vs 4.5 with resistance training (difference 11.4, 95% CI 8.9 to 14.0, P less than 0.001) at 6 months
- 21% of the training group crossed over to THA by 6 months; 9% of surgical group had not had surgery
- Serious adverse events similar between groups, mostly known THA complications
How Long Does a Hip Replacement Last? Registry Meta-Analysis
- Systematic review and meta-analysis of case series plus AOANJRR and Finnish registry data (over 215,000 registry THAs)
- 25-year pooled survival was 77.6% from case series but only 57.9% from national registries
- Registry estimates regarded as less biased - about 58% of hip replacements last 25 years
- Case-series data systematically overestimate implant longevity
Intra-articular Triamcinolone vs Saline: Cartilage and Pain
- 2-year double-blind RCT, 140 patients with symptomatic knee OA and synovitis (40 mg triamcinolone every 12 weeks vs saline)
- Triamcinolone caused significantly greater cartilage volume loss (-0.21 vs -0.10 mm; difference -0.11 mm)
- No significant difference in pain between steroid and saline at 2 years
- Does not support repeated scheduled corticosteroid injection for symptomatic OA
Exercise for Osteoarthritis of the Hip (Cochrane Review)
- Meta-analysis of 10 RCTs (549-715 participants) of land-based exercise vs no exercise
- High-quality evidence: exercise reduced pain (SMD -0.38) and improved physical function (SMD -0.38)
- Benefit sustained for at least 3 to 6 months after stopping supervised treatment
- No clear effect on quality of life; adverse events rare and minor
ACR Classification Criteria for Hip OA
- Multicentre study of 201 patients deriving classification criteria for hip OA
- Combined clinical plus radiographic criteria: hip pain plus 2 of - osteophytes, joint space narrowing, ESR under 20 mm/hr (sensitivity 89%, specificity 91%)
- Clinical-only tree uses pain, internal rotation, morning stiffness 60 min or less, age over 50
- Radiographic osteophytes best separated OA from other causes of hip pain
Global Burden of Osteoarthritis 1990-2020 (GBD 2021)
- 595 million people had OA in 2020 (7.6% of the global population), up 132% since 1990
- Hip OA cases projected to rise 78.6% by 2050 driven by ageing and population growth
- High BMI contributed to about 20% of OA burden
- Late-stage joint replacement is highly effective but may be out of reach in lower-resource settings, worsening health inequity
Bernese Periacetabular Osteotomy: 30-Year Experience
- Review of the Bernese PAO for dysplasia and acetabular retroversion 30 years after first description
- With optimal reorientation and a spherical head, 10-year cumulative hip survivorship is 80 to 90%
- Original first-75-patient series: 20-year survivorship 60%, falling to about 30% at 30 years
- PAO is now the standard joint-preserving procedure for symptomatic dysplasia in adolescents and adults
Exam Viva Scenarios
Use these scenarios to practise clinical reasoning and management decisions
Scenario 1: Classic Hip OA
"A 68-year-old woman presents with 2 years of progressive right groin pain worse with walking and stairs. She has stiffness in the morning for 20 minutes. X-rays show joint space narrowing, osteophytes, and subchondral sclerosis. She has not tried any formal treatment. What is your management?"
Scenario 2: Young Patient with OA
"A 42-year-old active man presents with bilateral hip pain and stiffness. X-rays show moderate bilateral hip OA with acetabular dysplasia (CE angle 18 degrees). He is frustrated with symptoms affecting his tennis. What is your approach?"
Scenario 3: Failed Conservative Treatment
"A 72-year-old woman has tried physiotherapy, lost 8kg, uses a walking stick, and has had two steroid injections over 18 months. She still has significant right hip pain limiting her to walking 200m and disturbing her sleep. X-rays show bone-on-bone changes. She asks about her options. What would you advise?"
MCQ Practice Points
Classic Presentation
Q: Where does true hip pathology cause pain? A: GROIN. Lateral pain = trochanteric bursitis. Buttock pain = sacroiliac or lumbar spine.
First Motion Lost
Q: What is the first motion lost in hip OA? A: Internal rotation. Often most painful as well. Test at 90 degrees flexion.
X-ray Findings
Q: What are the radiographic features of OA (LOSS)? A: Loss of joint space, Osteophytes, Subchondral Sclerosis, Subchondral cysts.
Kellgren-Lawrence
Q: What is Kellgren-Lawrence Grade 4? A: Large osteophytes, marked joint space narrowing, severe sclerosis, cysts, bone-on-bone. End-stage OA.
First Line Treatment
Q: What is first-line treatment for hip OA? A: Conservative: weight loss, exercise, physiotherapy, acetaminophen, walking aids. NSAIDs with caution.
THA Survival
Q: What is 15-year survival of THA? A: Greater than 95% in correctly selected patients. Higher revision in young, active patients.
Guidelines, Registries & Global Practice
Global Epidemiology
- 595 million people lived with osteoarthritis worldwide in 2020 (7.6% of the global population); hip OA cases are projected to rise about 79% by 2050 with population ageing.
- High BMI accounts for roughly one-fifth of total OA burden, making obesity the dominant modifiable risk factor.
- Symptomatic radiographic hip OA prevalence rises steeply after age 50; secondary OA (DDH, FAI, AVN, post-trauma) predominates in younger patients.
Side-by-Side Major Guidelines
How Major Societies Frame Hip OA Management
| Body | Core Recommendation | Notable Position |
|---|---|---|
| NICE (UK, 2022) | Therapeutic exercise as core treatment for all; offer arthroplasty when QoL substantially impaired | Do NOT refer based on age, sex, BMI or smoking alone; paracetamol/weak opioids deprioritised |
| OARSI (international) | Strongly recommends exercise and weight management; arthritis education core | Conditional support for topical/oral NSAIDs; IA steroid for short-term relief |
| AAOS (US, hip OA) | Strong evidence for NSAIDs and physical therapy; THA effective for end-stage disease | Limited/inconclusive evidence for viscosupplementation and glucosamine in the hip |
| ACR/AF (US) | Strongly recommends exercise, weight loss, oral/topical NSAIDs; conditional IA steroid | Strongly recommends AGAINST hyaluronic acid injection in the hip |
Registry Evidence
- National registries (AOANJRR, NJR for England and Wales, Swedish and Norwegian arthroplasty registries) consistently show THA among the most successful elective operations, yet report lower long-term survival than single-centre case series.
- Pooled registry data indicate about 58% of hip replacements survive to 25 years, versus the over-optimistic 78% from case series - the figure to quote when consenting younger patients.
- Registries demonstrate higher revision rates in younger, more active patients and have driven away from metal-on-metal bearings after high early-revision signals.
High- vs Limited-Resource Practice
Well-Resourced Settings
- Timely access to elective THA, advanced bearings, navigation/robotics in some centres
- Registry-guided implant selection and outcome surveillance
- Multidisciplinary conservative care (physiotherapy, weight-management programmes)
Limited-Resource Settings
- Arthroplasty may be unaffordable or unavailable, leading to prolonged conservative management and disability
- Greater reliance on analgesia, exercise and walking aids; later presentation with advanced disease
- GBD highlights this access gap as a driver of global health inequity
Orthopaedic Exam Relevance
Hip OA is extremely common in viva. Know conservative treatment first, THA indications, and be able to consent a patient with registry-based longevity figures (around 58% at 25 years). Discuss approaches, complications, and manage expectations appropriately.
HIP OSTEOARTHRITIS
Clinical summary
Presentation
- •Groin pain (true hip)
- •Activity-related, improves with rest
- •Morning stiffness (less than 30 min)
- •Internal rotation first lost
Radiograph (LOSS)
- •Loss of joint space
- •Osteophytes
- •Subchondral Sclerosis
- •Subchondral cysts
Conservative (WIPE)
- •Weight loss
- •Injections (steroid)
- •Physiotherapy
- •Exercise and NSAIDs
Kellgren-Lawrence
- •Grade 1: doubtful narrowing
- •Grade 2: definite osteophytes
- •Grade 3: definite narrowing
- •Grade 4: bone on bone
THA Indications
- •Failed conservative treatment
- •Significant functional impairment
- •Impact on quality of life
- •Radiographic OA
Secondary Causes (DAFT)
- •DDH (dysplasia)
- •AVN
- •FAI
- •Trauma