Summary

Osteoarthritis (OA) is a progressive disorder of the synovial joints characterised by the degeneration of articular cartilage and secondary changes in the underlying bone (sclerosis, osteophytes). It is the most common form of arthritis. Symptoms include mechanical pain (worse with activity, better with rest), stiffness ("gelling" after inactivity <30 mins), and crepitus. The Hip, Knee, Spine, and Hands (Base of thumb/DIPs) are most affected. Management follows a stepwise approach: Education/Weight Loss/Physio -> Analgesia -> Injections -> Joint Replacement (Arthroplasty). [1,2]

Key Facts

• Definition: Failure of repair of articular cartilage damage.
• Prevalence: 10% of men and 18% of women >60 have symptomatic OA.
• Risk Factors: Age, Obesity (Knee OA risk x4), Trauma (Post-traumatic OA).
• X-Ray Signs: L.O.S.S. (Loss of joint space, Osteophytes, Subchondral Sclerosis, Subchondral Cysts).
• Hand Signs: Heberden's Nodes (DIP), Bouchard's Nodes (PIP), Squaring of thumb base (1st CMCJ).

Clinical Pearls

"It's not just aging": While age is the biggest driver, OA is active pathology. It involves inflammatory mediators (IL-1) and enzyme activity (MMPs). It is "failed repair", not just passive wearing out (like a tire).

"Treat the Patient, Not the X-Ray": Many patients have terrible X-rays (KL Grade 4) but no pain. Conversely, some have mild changes and severe pain. Only operate on symptoms, never pictures.

"Referred Pain": 30% of "Knee Pain" comes from the Hip. The obturator nerve supplies both. ALWAYS examine the hip in any patient complaining of knee pain, especially if the knee examination is normal.

"Night Pain": Mechanical OA pain should stop when you lie down. If a patient has severe night pain that wakes them from sleep, consider:

1. Very severe end-stage OA.
2. Malignancy (Metastasis).
3. Infection.

          SYMPTOMATIC OSTEOARTHRITIS
                     ↓
             CORE TREATMENTS (All)
       (Education, Physio, Weight Loss)
                     ↓
             PHARMACEUTICALS
       (Paracetamol, Topical NSAIDs)
       (Avoid Opiates if possible)
                     ↓
             INTRA-ARTICULAR
       (Steroid Injection for flares)
                     ↓
        END STAGE + REFRACTORY PAIN?
                     ↓
             JOINT REPLACEMENT

1. Non-Surgical (The Foundation)

• Weight Loss: The most effective intervention for Knee OA. Every 1lb lost removes 4lbs of force from the knee.
• Physio: Strengthening the Quads offloads the knee.
• Unloader Braces: Shift load away from the damaged compartment.
• Walking Stick: Use in the Waiters Hand (Opposite side to the bad leg). Reduces hip joint reaction force by 50%.

2. Pharmacological

• Oral: Paracetamol (weak). NSAIDs (effective but gastric risK).
• Topical: NSAID gels (Diclofenac) - safer for elderly.
• Injections:
  • Corticosteroid: Good short term relief (3-6 weeks).
  • Hyaluronic Acid: Lubricant. Expensive. Evidence is mixed (NICE does not recommend).

3. Surgical: Arthroplasty (Replacement)

• Total Hip Replacement (THR):
  • Replaces Acetabulum (Cup) and Femoral Head (Ball).
  • "The Operation of the Century" (Lancet). >95% satisfaction.
  • Lifespan: 15-20 years.
• Total Knee Replacement (TKR):
  • Resurfacing the ends of the femur and tibia.
  • Satisfaction lower (80%). "The forgotten hip vs the grumbling knee".
  • Recovery is harder (painful rehab).

• Approaches:
  • Posterior: Most common in UK. Splits Gluteus Maximus. Risk of posterior dislocation.
  • Anterolateral: Lower dislocation risk. Risk of limp (Gluteus medius damage).
  • Direct Anterior: Muscle sparing. Faster recovery? Technically demanding.
• Fixation:
  • Cemented: "Grout" holds the stem. Better for osteoporotic bone (Elderly). Immediate fixation.
  • Uncemented: Titanium surface (Hydroxyapatite). Bone grows into the metal. Better for young/active.

Key Studies

1. OARSI Guidelines: Weight loss and Exercise are the only "Level 1A" treatments.
2. Moseley et al. (2002): Arthroscopy for OA (Washout) is Placebo. Do not fuse washout for degenerative knees.
3. Charnley: The father of the low-friction arthroplasty (HIP).

What is Osteoarthritis?

The smooth protective cap (cartilage) on the ends of your bones acts like Teflon. In OA, this wears away, leaving a rough surface. It's like a rusted hinge - it grinds and moves poorly.

Should I stop walking to save the joint?

Absolutely not. "Motion is Lotion". Cartilage has no blood supply; it feeds by being sponged during movement. If you stop moving, the joint starves and stiffens up. Walk little and often.

Will I need a replacement?

Only if the pain stops you sleeping or doing the things you love. We don't operate on X-rays, only on people. If you can manage, keep your own joint as long as possible.

Can I inject "Jelly" (Oil) into it?

Some private clinics offer Hyaluronic acid. It lubricates the joint for a while, like oiling a squeaky hinge, but it doesn't regrow the cartilage. It buys time, not a cure.