Rhizarthrosis

Original Editor - Jona Van den Broeck Top Contributors - Kirenga Bamurange Liliane, Lucinda hampton, Kim Jackson, Anas Mohamed, Jona Van den Broeck and Rosie Swift

Introduction

Trapeziometacarpal (TMC) arthritis ( also known as Rhizarthrosis ) is arthritis of the first carpometacarpal (CMC) joint of the thumb. The CMC joint of the thumb, or TMC joint plays a critical role in the normal functioning of the thumb. It is the most important joint connecting the wrist to the metacarpus. Osteoarthritis of the TMC is a severely disabling condition; up to twenty times more common among elderly women than in average.

Stages of CMC

The CMC stages are usually classified according to the Eaton-Litter Classification which is obtained through radiological procedures or arthroscopy . It's a staging protocol with four different stages based on synovitis, joint space, and the laxity of the capsule .

The four stages of Eaton-Litter Classification

Stage I: Synovitis Phase

• Articular contours are normal
• Possible widening of TMC joint that suggests joint effusion or ligament laxity
• No osteophyte formation

Stage II: Significant Capsular Laxity

• Narrowing of CMC joint
• Small osteophyte formation at the ulnar side of the distal trapezial articular surface
• No or 1/3rd CMC joint subluxation

Stage III: Significant Joint Destruction

• Further joint space narrowing with cystic changes and sclerotic bone
• Prominent osteophytes at the ulnar border of distal trapezium
• Moderate subluxation radially and dorsally at the base of the first metacarpal
• Mild arthrosis of the scaphotrapezial joint

Stage IV: Pantrapezial Arthritis

• Major subluxation of the joint
• Narrowing of the joint space as in stage 3
• Cystic and sclerotic subchondral bone changes
• Significant erosion and destruction of scaphotrapezial joint

<section> Stage 2: Significant Capslar Laxity

• Narrowingof CMC Joint
• Mild Subchondral sclerotic changes
• Small ( < 2mm) osteophyte formation commonly at the distal trapezial articular surface
• No or < 1/3 CMC joint sbluxation in any projection

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Etiology

Causes of TMC arthritis are:

• Excessive repetitive use of the CMC joint of the thumb
• Subluxation
• Lesion of the ligaments or a fracture.
• Laxity of the CMC joint can be hereditary, increased risk for ligament injuries, a primary stimulus in the development of arthritis. Also causes a hyperextension, which is another primary stimulus for the development of arthritis.
• Weakness of the cross links of the fingers (ligament oblique anterior). These ligaments are the most important stabilisers of the fingers. 
• Using thumb in occupation, For example, Work-related  thumb  pain  in  physiotherapists is a prevalent problem among physiotherapists who administer manual  techniques. Factors  that  appear to be associated  with  thumb  pain  include  CMC  mobility  and thumb   strength.

Signs and Symptoms

The first signs of arthritis in the thumb are

• pain, tenderness, and stiffness at the base of your thumb. This occurs with gripping, pinching, or clasping something between the thumb and index fingers or when a mild force, such as when you twist a key in a lock or turn a door handle. An ache after activity can also be a feature.

• Decreased strength and range of motion, For example, opening jars or doing up buttons may become difficult.

• Appearance. The joint may become swollen or develop a bony bump. The joint may appear squarish and enlarged.

Diagnosis

• Noticeable lumps or swelling on the first CMC joint
• Thumb CMC grind test
• Plain radiographs showing degenerative changes (bone spurs, thinning of cartilage, loss of joint space) in affected joints are usually diagnostic.

Treatment

Conservative measures are the first options for CMC arthritis and can ameliorate symptoms in most cases. These include

Behaviour modification

For example, Try to avoid: clenching your hands when carrying things; repetitive movements that involve pinching or twisting

^{Physiotherapy}

Techniques include

• range-of-motion and stretching exercises to improve thumb motion.

• Advance to include strength exercise for the thump and fingers.

• Dexterity and fine motor exercises for the hand and thumb.
• Application of therapeutic heat or cold
• Application of electro therapeutic techniques, For example, Therapeutic Ultrasound, TENS. Ultrasound has been found to have the ability to evoke a broad range of therapeutically beneficial such as improved pain and functional outcomes, positive cartilage healing properties and positive phonophoresis for hyaluronan.
• Acupuncture. May work in pain relief for some people.
• Splinting, designed to help reduce pain, prevent deformity, or prevent deformity from getting worse. To wear at night, during flare ups and when doing heavy work with hand.
• Clinical trials have provided evidence that a combination of joint mobilization, neural mobilization, and exercise helps with CMC joint pain.

Pain relief

Options include

• Topical medications, such as capsaicin or diclofenac, which are applied to the skin over the joint
• Over-the-counter pain relievers, such as acetaminophen, ibuprofen or naproxen sodium
• Prescription pain relievers, such as celecoxib (Celebrex) or tramadol (Conzip, Ultram)
• Injections. Corticosteroid injections can offer temporary pain relief and reduce inflammation.

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^Surgery

If the diagnosis of ‘rhizarthrosis’ is determined too late, none of the above treatments will be helpful. Because of severe pain and movement restriction, surgery could be inevitable.