Primary Osteoarthritis of the Hip

Definition

• Degeneration of the tissues of the hip joint, including hyaline cartilage, fibrocartilage, bone & synovium

Prevalence

• 3% to 6% in the Caucasian population
• Asian, black, & East Indian populations have very low prevalence of hip Osteoarthritis

Types

• Primary osteoarthritis (Osteoarthritis) of the hip (90%)
  • a diagnosis made by exclusion
• Secondary osteoarthritis of hip
  • osteonecrosis, trauma, sepsis, or rheumatoid arthritis
  • congenital hip disease & slipped capital femoral epiphysis

Aetiology

• Genetic
  • Family studies from Sweden, Britain, & the United States show ↑ rates of hip Osteoarthritis in first-degree relatives of the index patient when compared with the normal population
  • low prevalence of hip Osteoarthritis in Asian & black populations in their native countries; the low incidence of total joint replacement for primary Osteoarthritis in Asian, black, & Hispanic populations in North America; & the familial association of hip Osteoarthritis in Caucasians all suggest that genetic factors may be involved in the occurrence of this disease
  • Rate of THRCaucasians 75 per 100,000 persons
    • blacks had half the incidence
    • Asians had only one tenth.
• Location
  • incidence of Osteoarthritis was not related to latitude or longitude

• Body Weight
  • Osteoarthritis of the knee has been shown to be consistently related to obesity
  • Hip Osteoarthritis: controversial
  • no relationship between body weight or body-mass index & the occurrence of hip Osteoarthritis. However, other studies have shown an ↑ risk of Osteoarthritis of the hip in obese individuals
• Occupational Factors
  • Occupations requiring heavy lifting, farming, & elite sports activity are associated with ↑ rates of hip Osteoarthritis
  • ? exacerbate hereditary predisposition to Osteoarthritis of the hip
    • work
      • physical demands of work have been estimated to account for 40% of cases of hip Osteoarthritis
    • carrying heavy loads
    • farmers
    • track, field, & racket sports soccer players
• Other Anatomic Considerations
  • DDH
  • acetabular abnormality
  • femoral anteversion
    • not shown

Predisposing Anatomic Abnormalities

• Hip dysplasia
  • If primary Osteoarthritis of the hip is due to a subtle dysplasia, it should be seen frequently in Japanese persons, with their extremely high rate of dysplasia; however, primary Osteoarthritis is rare in that population
  • incidence of DDH in Caucasians is 0.5%. If Osteoarthritis developed in all children with DDH, this would account for only one eighth of the cases of Osteoarthritis in the Caucasian population
  • In summary, when controlled studies of acetabular measurements are done & the rates of DDH & Osteoarthritis for each racial subgroup are considered, DDH accounts for only a small percentage (5% to 10%) of hip Osteoarthritis in Caucasians
• clinical SUFE in the adolescent occurs in only 1 of every 800 boys (an incidence of only 0.125%)
  • Anatomically normal femora accounted for more than 80% of the Osteoarthritis in their series
  • Furthermore, although there is little primary Osteoarthritis in the black & Polynesian populations, as well as a low incidence of THR performed because of Osteoarthritis, these populations have two to four times the rate of SUFE in Caucasians.

Grading

Kellgren grading was used to describe the degree of hip arthritis.

Grade	Description
0	None
1	Doubtful
2	Minimal
3	Moderate
4	Severe

Original publication Kellgren JH, Lawrence JS. Radiological assessment of osteo-arthrosis. Ann Rheum Dis. 1957;16(4):494-502.

References

JAAOS

Contribution

Phong Tran

Reviewed by Professor Phong Tran, Head of Orthopaedic Surgery, Western Health. Last updated 10 October 2026.