Osteoarthritis of Hip

Introduction - Joint's Slow Grind

• Chronic, progressive degeneration of hip articular cartilage; "wear & tear" arthritis.
• Results in joint pain, stiffness, ↓ function, and ↓ range of motion (ROM).
• Types:
  • Primary (Idiopathic): Most common, age-related (typically >50 yrs).
  • Secondary: Due to pre-existing conditions (e.g., trauma, Developmental Dysplasia of Hip (DDH), Femoroacetabular Impingement (FAI), Avascular Necrosis (AVN), Perthes disease).
• Key pathology: Cartilage loss, osteophyte formation, subchondral sclerosis.
• Prevalence ↑ with age, obesity, genetics, previous joint injury.

⭐ Osteoarthritis of the hip is the most common form of arthritis affecting this joint, primarily characterized by cartilage degradation and osteophyte formation.

Risk Factors - Pathway to Pain

• Primary (Idiopathic):
  • Age >50 years
  • Female (post-menopause)
  • Genetics
  • Obesity (BMI >30): stress, adipokines
• Secondary:
  • Trauma (fractures)
  • Developmental (DDH, Perthes, SUFE)
  • Inflammatory (RA)
  • AVN
  • Occupational stress
• Pathway: Cartilage loss → bone changes (sclerosis, cysts) → osteophytes → synovitis → pain.

⭐ Previous hip injury significantly increases the risk of developing secondary osteoarthritis.

Clinical Features - Groans & Gaits

• Pain (Groans):
  • Insidious onset, deep aching character.
  • Location: Groin (commonest, C-sign), anterior thigh, buttock; may refer to knee.
  • Worse with activity/weight-bearing, improves with rest.
  • "Start-up" pain after inactivity.
• Stiffness:
  • Morning stiffness, typically < 30 minutes.
  • Gelling phenomenon (stiffness after rest).
• Gait Disturbances (Gaits):
  • Antalgic gait (shortened stance phase on affected side).
  • Trendelenburg gait (due to abductor weakness, pelvis drops on contralateral side).
  • Limp.
• Functional Limitation: Difficulty with ADLs (e.g., stairs, putting on socks/shoes).

⭐ Restricted and painful internal rotation is often the earliest clinical sign of hip osteoarthritis.

Diagnosis - Imaging Insights

• X-ray (AP pelvis & lateral hip): Initial & primary imaging.
  • Hallmark findings (📌 Mnemonic: LOSS):
    • Loss of joint space (superior > medial)
    • Osteophytes (femoral & acetabular)
    • Subchondral sclerosis
    • Subchondral cysts
• Kellgren-Lawrence (KL) Grading: Assesses severity (Grade 0-4).
  • Grade 2: Definite osteophytes, possible joint space narrowing (JSN).
  • Grade 3: Moderate osteophytes, definite JSN, some sclerosis.
  • Grade 4: Large osteophytes, severe JSN, marked sclerosis, cysts.

⭐ Earliest sign on X-ray: Osteophytes, often at the femoral head-neck junction or acetabular rim.

• MRI: Not routine; for early changes or when X-ray is normal but suspicion high (cartilage loss, labral tears, bone marrow edema).

Management - Motion Makeover

• Goals: Pain relief, ↑ function, delay progression.
• Conservative:
  • Lifestyle: Weight loss (if BMI > 25), activity modification.
  • Physiotherapy: Exercises, assistive devices (cane).
  • Pharmacological: Paracetamol, NSAIDs, intra-articular corticosteroids/hyaluronic acid.

![Post-op X-ray of Total Hip Replacement](https://ylbwdadhbcjolwylidja.supabase.co/storage/v1/object/public/notes/L1/Orthopaedics_Degenerative_Disorders_Osteoarthritis_of_Hip/e285df22-445a-4483-a5be-54516d0ad4dc.gif)

• Surgical Details:
  • Total Hip Replacement (THR): Primary choice for advanced OA.
  • Osteotomy: Realigns joint; for younger patients.

⭐ Total Hip Replacement (THR) is one of the most successful and cost-effective surgical interventions in medicine.

High‑Yield Points - ⚡ Biggest Takeaways

• Groin/anterior thigh pain, worse with activity, is characteristic of hip OA.
• Loss of internal rotation is an early and significant clinical sign.
• Radiographs reveal superolateral joint space narrowing, osteophytes, and subchondral sclerosis/cysts.
• Morning stiffness is typically brief, lasting < 30 minutes.
• Trendelenburg gait may be present due to abductor muscle weakness or pain.
• Total Hip Arthroplasty (THA) is the definitive surgical treatment for advanced, debilitating disease.
• Major risk factors include advanced age, obesity, and prior hip joint injury or disease.