Epidemiology and prognosis of osteoarthritis

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Joost Dekker PhDDepartment of Rehabilitation Medicine & Department of Psychiatry VU University Medical Center, Amsterdam, Netherlands

Contents

• Definitions

• Prevalence, Incidence

• Prognostic factors for development of OA

• Course and prognosis of activity limitations in OA

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Definitions

• Radiographic OA– Kellgren – Lawrence grading – KL ≥ 2 (KL ≥ 1)

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Kellgren & Lawrence grading

0 - No radiographic features of osteoarthritis

1 - Possible joint space narrowing and osteophyte formation

2 - Definite osteophyte formation with possible joint space narrowing

3 - Multiple osteophytes, definite joint space narrowing, sclerosis and possible bony deformity

4 - Large osteophytes, marked joint space narrowing, severe sclerosis and definite bony deformity

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Definitions

• Radiographic OA– Kellgren – Lawrence grading – KL ≥ 2 (KL ≥ 1)

• Symptomatic OA– Radiographic + symptoms (pain, stiffness)

• Clinical OA– Symptoms

– American College of Rheumatology (ACR) criteria– Knee pain in older people

• Activity limitations in OA5

• Prevalence and Incidence

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Suri et al, PM&R, 2012

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• Prognostic factors for development of OA (radiographic, symptomatic)

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10Suri et al, PM&R, 2012

Suri, Morgenroth and Hunter, PM&R, 2012

• Figure 1: Potential risk factors • Narrative review

• Evidence for some risk factors for incidence/progression of OA– Age, gender, overweight/obesity– Joint injury, limb-length inequality, alignment, hip dysplasia

• Evidence for other risk factors less clear

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Silverwood et al, 2015

• Meta-analysis

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Silverwood et al, 2015

• Systematic review– Overweight, obesity– Previous knee injury– Female gender– Age– Occupational factors (see also Ezzat et al, Physiotherapy Canada, 2014)

– Intense physical activity

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Risk factors for the development of OA (radiographic, symptomatic)• Evidence from meta-analyses and systematic reviews

– Systemic factors : Age, gender, overweight/obesity– Local factors: Joint injury, limb-length inequality, alignment,

hip dysplasia, occupational factors, intense physical activity, muscle weakness

• Rapid developments– Evidence will change

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• Course and prognosis of activity limitations

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Course of activity limitations

• Highly variable

• Worse, stable and better functioning

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Dekker, 2009

Course of activity limitations in early knee OA

Holla et al, 2014 19

Characteristics of the subgroups

• Subgroup 2 (‘moderate outcome’) compared with Subgroup 1 (‘good outcome’) –Higher BMI –Greater knee pain, hip pain–Less vitality/more fatigue–≥3 comorbidities

• Subgroup 3 (‘poor outcome’) compared with Subgroup 1 (‘good outcome’)–Younger age–Greater knee pain, hip pain–Bony tenderness, lower range of active knee flexion, osteophytosis–Less vitality/more fatigue–Resting/avoidance of activity–≥3 comorbidities

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Prognosis of pain and physical functioning in knee OA - Systematic review

• Strong evidence on– Knee characteristics

– worsening in radiographic osteoarthritis

– bilateral knee symptoms– higher knee pain at baseline– worsening of knee pain– pain on patella-femoral joint

compression– lower knee extension strength

• Strong evidence on– Clinical factors

– lower walking speed– more disability– higher morbidity count– poor general health

– Psychosocial factors – lower vitality– poor mental health– more depressive symptoms.

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de Rooij et al, submitted

Summary

• Radiographic OA, Symptomatic OA, Clinical OA, Activity limitations in OA

• Risk factors for the development of OA (radiographic, symptomatic)

– Systemic factors : Age, gender, overweight/obesity– Local factors: Joint injury, limb-length inequality, alignment,

hip dysplasia, occupational factors, intense physical activity, muscle weakness

• Activity limitations in OA– Highly variable– Knee characteristics, clinical factors, psychosocial factors

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