Also known as small joint arthritis, this is a very common condition. The fingers contain multiple joints — each finger has three joints, the metacarpophalangeal (MCP) joint, the proximal interphalangeal (PIP) joint in the middle of each finger, and the distal interphalangeal (DIP) joint at the fingertips. Any of these may be affected by osteoarthritis or inflammatory arthritis.

Osteoarthritis is by far the most common form. The protective cartilage that cushions the joint surfaces gradually wears away, causing bone-on-bone contact, pain, swelling, stiffness and the development of bony lumps at the affected joints. It affects the DIP and PIP joints mostly bit it can also affect MCP joints.

Rheumatoid arthritis is an autoimmune inflammatory condition that attacks the lining of the joint capsule (synovium), causing progressive loss of cartilage and disruption of joint mechanics. Mostly, rheumatoid arthritis affects the MCP joints.

Both conditions can progress to the point where pain and deformity are severe enough to warrant surgical intervention. The choice of surgical procedure — joint replacement or joint fusion — depends on which joint is affected, the type of arthritis, the degree of deformity, the patient’s age, activity level, functional requirements and preferences.

• Pain and tenderness in one or more finger joints, usually worse with activity and better with rest.
• Bony lumps, swellings and deformity of affected joints.
• Loss of joint movement range.
• Weakness and reduced dexterity

Finger joint replacement (arthroplasty) removes the damaged arthritic joint surfaces and replaces them with prosthetic components, aiming to restore pain-free movement while preserving the functional arc of the finger. The concept is similar to hip or knee replacement, adapted for the small joints of the hand.

Joint replacements do not restore a normal range of motion; typically the range will be approximately half of the normal joint range.

Silicone joint replacement implants have been used for decades. They provide pain relief in almost all cases. The silicone spacer acts as a hinge, allowing flexion and extension. They are durable and well-tolerated. Any of the 3 finger joints can be treated with silicone joint replacements.

Surface replacement arthroplasty (SRA) — using metal and polyethylene components. These are more complex types of implant. They offer no clear advantage over the silicone joint replacements and have a higher rate of revision and complications. Mr Harley does not typically use these.

Usually the treated finger will be bandaged to its neighbour and immediate gentle exercise will be advised.

Arthrodesis is a procedure in which the arthritic joint surfaces are removed and the two bones on either side of the joint are fused together in a fixed, functional position. This may be done using internal fixation such as a headless compression screw or pins.

Once fused the joint is pain free but it will have no movement range. Although the loss of movement at the joint may seem disadvantageous, it is important to understand that an arthritic joint has usually lost movement range of movement. Adjacent finger joints will typically compensate, and most patients adapt readily to the fused position.

The position in which the joint is fused is selected to optimise function.

The main advantage of arthrodesis is joint stability in the context of patients who do forceful jobs or activities.