Trapezoid metacarpal (TMC) arthritis (also known as arthrosis) is arthritis of the first carpus metacarpal (CMC) joint of the thumb. The CMC joint or TMC joint of the thumb plays a vital role in the normal function of the thumb. It is the most important joint that connects the wrist to the wrist metacarpal. Osteoarthritis in TMC is a severely disabling disease; it occurs 20 times more frequently than average in older women. 
Carpometacarpal Joint of the hand
Ligaments of the TMC joint and their functions
The major ligaments of the TMC joint are as follows:   
- The dorsoradial ligaments (DRL)
- 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. Functions of the ligaments (table adapted from Blige & Karalezli 2015 
Ligament Function The shortest and thickest ligament of the dorsal radius. The primary stabilizer against dorsal translation of the joint is the superficial stabilizer against volar joint subluxation by the anterior oblique, also known as the coracoid ligament. It acts as a pivot master joint stabilizer Oblique stabilization after dorsal translation Intermetacarpal stabilization Ulnar collaterals help stabilize volar joint subluxation during radial translation
Although there is controversy regarding the primary stabilizer of the TMC combination, several studies have concluded that DRL is the primary stabilizer  
Stages of CMC
CMC stages are usually classified according to the Eaton-Litter classification obtained by radiological procedures or arthroscopy . This is a staging scheme with four distinct stages based on laxity of the synovitis joint space and joint capsule .
Following are the four stages of Eaton-Litter classification :
Stage I: Synovitis Phase
- Articular contours are normal
- TMC Joints may widen, suggesting joint effusion or ligamentous laxity
- No osteophyte formation
Stage II: Significant Capsular Laxity
- Narrowing of CMC joint
- Formation of small osteophytes on the ulnar side of the distal trapezoidal articular surface
- No or 1/3rd CMC joint subluxation
Stage III: Significant Joint Destruction
- Further narrowing of the joint space with cystic changes and osteosclerosis
- Osteophytes protruding from the distal trapezoidal ulnar border
- Radial and dorsal moderate subluxation of the base of the first metacarpal
- Mild arthrosis of navicular joint
Stage IV: Pantrapezial Arthritis
- Major subluxation of the joint
- Narrowing of the yolk sac as in section 3
- Cystic and sclerotic subchondral tumors in the sacrum
- Severe prolapse and degeneration of the scaphotrapezial joint
Causes of TMC arthritis are:
- CMC joints used too often
- Lesion of the ligaments or a fracture.
- CMC joint weakness may be an increased genetic risk factor for muscle injury triggered primarily in the development of rheumatoid arthritis. Also leads to hyperextension which is another important trigger for arthritis.
- Cruciate weakness of the elbow (anterior oblique ligament). These muscles are the most important stabilizers of the elbow.  .
- Using the thumb in the profession, for example, physical therapists Work-related thumb pain is a common problem among physical therapists administering manual techniques. Factors that appear to be associated with thumb pain include CMC mobility and thumb strength .
Signs and Symptoms
The first signs of thumb arthritis are
- Painful tenderness and stiffness at the base of the thumb. This happens when you pinch or grip something between your thumb and forefinger, or when you apply light force when turning a key in a lock or turning a doorknob. Pain after activity may also be a feature.
- Reduced strength and range For example, opening cabinets or making buttons up can be difficult.
- Appearance. The joints may be swollen or bony. The joints may appear triangular and enlarged.
- Medical and family history
- Swelling or inflammation appearing on the first CMC joint
- Thumb CMC grind test
- Plain radiographs showing degenerative changes (bone spurs thinning of cartilage loss of joint space) in the involved joints are usually diagnostic.
The differential diagnosis of Rhizarthrosis includes:  .
- De Quervain’s disease
- Trigger thumb
- Scaphoid fracture
- Flexor carpi radialis (FCR).
- Scaphotrapezial arthritis
- Wrist arthritis
- Subsesamoid arthritis
Prevention is the first option for CMC neuropathy and can improve symptoms in most cases. These include
For example try to avoid: clenching your arms when carrying objects; conventional movements involving pinching or twisting
- range-of-motion and stretching exercises to improve the wrist.
- Go ahead for strength exercises including for the intrinsic and extrinsic thumb muscles and finger muscles.
- Dexterity and fine motor exercises for hands and fingers.  .
- Use of heat or cold therapy
- Electrotherapeutic techniques used For example Therapeutic Ultrasound TENS. Ultrasound has been found to have the ability to induce many therapeutic benefits such as improved pain and positive functional outcomes for neuropathology and good phonophoresis hyaluronan implants.  .
- Acupuncture is administered. It may work in pain relief for some people.
- Clinical trials have provided evidence that a combination of joint stimulating muscle stimulation and exercise helps CMC joint pain.
- Pain splints designed to help reduce pain have prevented or prevented disability from becoming worse. To be worn at night during fires and during heavy manual labor.
- Topical medications such as capsaicin or diclofenac applied to the skin over the joints
- Over-the-counter pain relievers, such as acetaminophen, ibuprofen or naproxen sodium
- Prescription pain relievers, such as celecoxib (Celebrex) or tramadol (Conzip Ultram)
- injection. Corticosteroid injections can temporarily relieve pain and reduce inflammation. 
None of the above treatments will help if the diagnosis of “root nodule” is made too late. Surgery may be unavoidable due to severe pain and motion limitations. The following options are usually offered for surgery:
- Arthroscopy: Removal of part of the trapezium bone
- Arthrodesis to fuse the first metacarpal and trapezium bones
- Arthroplasty by reconstruction of the joint using a prosthesis, such as Swanson’s trapezoidal implant arthroplasty  or the Artelon spacer. [twenty two]
Other treatment techniques may also include:
- Denervation of the TMC joint
- Reconstruction of the volar coracoid ligament
- Suture button suspensionplasty
Possible complications after surgery include:
- Incision tenderness
- Joint Stiffness
- Mild metacarpal subsidence
2. Uncommon Complications
- Nerve irritation/numbness
- Recurrent pain
- Tendon anchovy extrusion
- Tendon adhesions or ruptures
- Deep vein thrombosis
- Pulmonary embolus
- Myocardial infarction
- Mild metacarpal subsidence
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