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; it is up to twenty times more common among elderly women than on average.

Carpometacarpal Joint of the hand

Ligaments of the TMC Joint and their functions

The main ligaments of the TMC Joint are as follows:

• The dorsoradial ligaments (DRL)
• The superficial anterior oblique ligament (AOL)
• The deep anterior oblique ligament (AOL)
• The intermetacarpal ligament (IML)
• The ulnar collateral ligament
• The posterior obique ligament

Table 1. The Functions of the ligaments (table adapted from Blige & Karalezli 2015

Ligament		Function
Dorsoradial		Shortest and thickest ligament. Primary stabilizers against dorsal translation of the joint
Anterior oblique	Superficial	Stabilization against volar joint subluxation
Anterior oblique	Deep	It is also known as beak ligament. It acts as a pivot primary joint stabilizer against dorsal translation
Posterior oblique		Stabilization of rotation
Intermetacarpal		Stabilization during radiovolar translation
Ulnar collateral		Helps to stabilize against the volar joint subluxation

Although there is a controversy about the primary stabilizers of the TMC Joint, several studies concluded the DRL to be the primary stabilizers

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 .

Here are 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 Capsular Laxity

• Narrowing of 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 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 stabilizers 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

• Medical and family history
• 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.

Differential Diagnosis

The differential diagnosis of Rhizarthrosis includes:

• De Quervain's disease
• Trigger thumb
• Scaphoid fracture
• Flexor Carpi Radialis (FCR) tenosynovitis
• Scaphotrapezial arthritis
• Wrist arthritis
• Subsesamoid arthritis

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 intrinsic and extrinsic muscles of the thumb and muscles of the fingers.

• Dexterity and fine motor exercises for the hand and thumb.
• Application of therapeutic heat or cold
• Application of electrotherapeutic 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.
• Clinical trials have provided evidence that a combination of joint mobilization, neural mobilization, and exercise helps with CMC joint pain.
• 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.

Rhizarthrosis splint

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.

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. The following options are usually offered for surgery:

• Arthroscopy: resecting a part of the trapezium bone
• Arthrodesis to fuse the first metacarpal bone and the trapezium bone
• Arthroplasty to reconstruct the joint by the use of a prosthesis such as Swanson’s trapezium implant arthroplasty  or the Artelon spacer.

Other treatment techniques may also include:

• Denervation of the TMC joint
• Reconstruction of the volar beak ligament
• Suture button suspensionplasty

Complications

Complications that may arise after surgery include:

Common complications

• Swelling
• Bruising
• Incision tenderness
• Joint Stiffness
• Mild metacarpal subsidence

2. Uncommon Complications

• Hematoma
• Infection
• Nerve irritation/numbness
• Recurrent pain
• Tendon anchovy extrusion
• Tendon adhesions or ruptures
• Deep vein thrombosis
• Pulmonary embolus
• Myocardial infarction
• Death
• Mild metacarpal subsidence