Introduction
Osteoarthritis (OA) of the hands is sometimes referred to as nodal arthritis. It results from the loss of cartilage at synovial joints and is often accompanied by the degeneration of underlying bone. Inflammation is not usually involved.
Epidemiology
- Incidence: 6000.00 cases per 100,000 person-years
- Peak incidence: 70+ years
- Sex ratio: more common in females 2:1
| Condition | Relative incidence |
|---|---|
| Osteoarthritis of the hand | 1 |
| Rheumatoid arthritis | 0.01 |
| <1 | 1-5 | 6+ | 16+ | 30+ | 40+ | 50+ | 60+ | 70+ | 80+ |
Aetiology
Risk factors:
- Genetics: Genes that encode for ‘collagen type II’ are thought to be involved especially in interphalangeal involvement. There is ongoing research into this.
- Previous trauma of a joint increases the risk of having OA in that joint
- Obesity
- Hypermobility of a joint increases the risk of OA in that joint
- Occupation e.g. cotton workers and farmers are more susceptible to hand OA
- Osteoporosis reduces the risk of OA
Clinical features
Features:
- Usually bilateral: Usually one joint at a time is affected over a period of several years. The carpometacarpal joints (CMCs), distal interphalangeal joints (DIPJs) are affected more than the proximal interphalangeal joints (PIPJs).
- Episodic joint pain: An intermittent ache. Provoked by movement and relieved by resting the joint.
- Stiffness: Worse after long periods of inactivity e.g. waking up in the morning. Stiffness lasts only a few minutes compared to the morning joint stiffness seen in rheumatoid arthritis.
- Painless nodes (bony swellings): Heberden’s nodes at the DIPJs, Bouchard’s Nodes at the PIPJs. These nodes are the result of osteophyte formation.
- Squaring of the hand: Deformity of the carpometacarpal joint of the thumb resulting in fixed adduction of the thumb.
- Functionally patients do not usually have any problems. If there is severe involvement of the DIPJs, there may be reduced grip strength which can result in disuse atrophy.
Investigations
Investigations:
- X-ray: radiologically there are osteophytes and joint space narrowing. Often signs may be visible on X-ray, before symptoms develop