Wrist Replacement

Original Editor - Simisola Ajeyalemi

Top Contributors - Simisola Ajeyalemi, Peace Samuel, Rachael Lowe, Admin, Kim Jackson, Amanda Ager and Lucinda hampton

Description

Wrist replacement, also referred to as wrist arthroplasty is a surgical procedure in which the diseased or damaged joint is replaced with an artificial joint- a prosthesis. It aims to create a stable, pain-free joint with a functional range of movement when conservative treatments have failed.

Total wrist arthroplasty (TWA) is a motion preserving alternative to arthrodesis of the wrist and usually lasts for about 10 to 15 years. Implant survival of 90-100% at five years are mostly reported using newer second generation and third generation implants, but declines from five to eight years.

Total wrist replacements are non-weight bearing joints; heavy household or occupational activity, use of a walking aid or repetitive movements e.g. hammering will increase the speed and incidence of loosening of the implants stems and the ultimate failure of the implant. The ideal patient for a TWA should have a low demand lifestyle, should not need the upper extremity for regular ambulation and transfers. Young active patients and individuals with high physical demands are not considered good candidates for TWA.

Clinically Relevant Anatomy

The wrist/radiocarpal joint is a ellipsoid type of synovial joint. The wrist consists of two rows of carpal bones which forms the proximal segment of the hand and articulates proximally with the forearm via the wrist joint and distally with the five metacarpals. The ends of the bones are covered with articular cartilage. Cartilage is an elastic connective tissue whose purpose is to allow for a smooth, gliding motion between joints.^[1] Movements occurring in the wrist include flexion, extension adduction and abduction. Diseases such as osteoarthritis and rheumatoid arthritis, injury and infection can damage or wear out the articular cartilage. This may cause the wrist bones to rub against each other producing pain, stiffness and swelling of the wrist.

The Artificial Wrist

Earlier designs of wrist implants had high complications and failure rates, however, advances in prosthetic design have contributed to improved clinical outcomes and greater implant longevity. The implant is made from metal and plastic and has 2 components- radial and distal component.

The radial component: is the part that fits against the end of the radius bone. It is made up of two pieces- a flat metal piece with a stem that attaches down into the canal of the bone and a plastic cup that fits onto the metal piece, forming a socket for the artificial wrist joint.

The distal component: is the part that replaces the small wrist bones. This piece is made completely of metal. It is globe shaped to fit into the plastic socket on the end of the radius. It is attached by two metal stems that fit into the hollow bone marrow cavities of the carpal and metacarpal bones of the hand. The ellipsoidal head simulates the curvature of the natural wrist and allows for a functional range of movement.

The prosthesis typically is stable and should demonstrate approximately 35⁰ of flexion and 35⁰ of extension with modest tightness at full extensions.

Clinical Presentation

One of the common conditions encountered by hand surgeons is wrist arthritis. It can be caused by so many factors but subsequent abnormal joint loading produces a spectrum of symptoms, from mild swelling to considerable pain and limitations of motion as the involved joints degenerate.  Typical symptoms of arthritis at the wrist include:

• Pain

• Stiffness

• Swelling

• Reduced range of motion

• Clicking, cracking or grinding sounds on movement

Indications

Arthritis may result from a non-united or mal-united fracture of the scaphoid or distal radius, disruption of the intercarpal, radiocarpal, radioulnar, or ulnocarpal ligaments; avascular necrosis of the carpus; or a developmental abnormality. Other indications are:

• Wrist osteoarthritis

• Rheumatoid arthritis

• Post-traumatic arthritis

• Failed wrist fusion

• Advanced avascular necrosis of the carpal bones

• Kienbock disease

Contra-indications

• Infection at the wrist
• Severe ligamentous laxity in form of severe volar subluxation

• Highly active synovitis in patients with RA

• Systemic lupus erythematosus

• Patients with minimally functional hand

• Lack of active wrist extension

Complications of Wrist Arthroplasty

Significant complications arise from Wrist Arthroplasty and these include:

• Instability of the wrist
• Post-operative stiffness
• Infection
• Intraoperative fractures
• Dislocation of the wrist
• Loosening of implants
• Damage to the nerves or blood vessels,
• Implant failure
• Peri-prosthetic fractures

Diagnostic Tests

Wrist arthritis is usually diagnosed following a review of medical history, a physical examination, and an X-ray-which is characterized by loss of joint space between the bones. Additionally, blood tests may also be ordered to confirm the presence of rheumatoid factor which suggests rheumatoid arthritis.

Pre-Op

In patients with rheumatoid arthritis, a comprehensive pre-operative evaluation should be carried out. Prior to wrist arthroplasty, a hip or knee replacement surgery should be carried out to prevent weight bearing on the wrist prosthesis, improve hand balance and optimize rehabilitation of the digits.

Patients for wrist arthroplasty should temporarily discontinue medications such as methotrexate (anti rheumatic) and immune-modulating drugs after consulting with their rheumatologist to reduce the risk of infections and delayed wound healing. NSAIDs should also be reduced at least 10 days pre-operatively and 5 days post-operatively to reduce the risk of bleeding complications.

Radiographic assessment of bone quality, erosions, carpal collapse, carpal ulnar translations, volar subluxation and distal radioulnar joint. In PA view, the radial component should not extend beyond the edge of the styloid while the carpal component should not extend > 2mm over the margins of the carpus at osteotomy.

Pre-op rehabilitation includes exercises to maintain strength and function of non-affected extremity and other joints of affected extremity and education on post-operative exercises.

Post-Op Rehabilitation

Regaining function of the hand following TWA is largely dependent on post-operative physiotherapy. Physical therapy should be started early beginning with gentle mobiliation exercises and gradually progressing to resisted exercises.

0-2 weeks

• post-operative dressing

• wrist is immobilized in neutral alignment

• elevation of the limb to control swelling

• mobilization of adjacent joints- shoulder and elbow joints

3-5 weeks

• removal of post-operative dressing

• static splinting at 15⁰ of flexion(worn during exercise and at night)

• gentle passive and active range of motion exercises for the wrist and fingers

• scar massage

6-12 weeks

• full PROM at the wrist minimizing radial and ulnar deviation of the wrist

• dynamic splint

• gentle progressive strengthening of the wrist and hand

• gradual return to normal activities

Don'ts after Wrist Replacement

• do not lift more than 2 pound on a regular basis
• do not lift more than 10 pounds on occasional basis
• avoid placing your arm in extreme positions
• avoid impact loading- hammering, weight bearing

Outcome Measures

• Disabilities of Arm, Shoulder and Hand Score (DASH) - This is a self-administered region-specific outcome measure developed as a measure of self-rated upper-extremity disability and symptoms. It consists mainly of a 30-item disability/symptom scale, scored 0 (no disability) to 100.
• The Munich Wrist Questionnaire (MWQ) - The MWQ is a valid and reliable measure for a qualitative self-assessment of subjective and objective parameters (e.g. range of motion) of the wrist joint. It covers a broad application in clinical research and may facilitate the comparison of treatment results in wrist disorders.

• Patient Related Wrist Evaluation (PRWE) - This is used as a reliable, valid, and structurally sound questionnaire to assess pain and disability in patients with various wrist and hand injuries. Currently, PRWE has been translated into 21 languages.
• Quality-of-Life Measures - The Quality-of-Life Scale (QOLS), was originally created by American psychologist John Flanagan in the 1970's, has been adapted for use in chronic illness groups. It was originally a 15-item instrument that measured five conceptual domains of quality of life: material and physical well-being, relationships with other people, social, community and civic activities, personal development and fulfilment, and recreation. It has now been adopted as a 16 item where independence is being measured as a quality of life. The QOLS is scored by adding up the score on each item to yield a total score which can range from 16 to 112. There is no automated administration or scoring software for the QOLS.

• Michigan Hand Outcome Questionnaire (MHQ) - This was first developed at the University of Michigan in 1998. The MHQ uses rigorous psychometric principles to provide a multidimensional measure of the health status of patients with hand and wrist disorders. It consists of 37 items assessing 6 domains: overall hand function, activities of daily living, work, pain, aesthetics and satisfaction. It assesses the left and right hand separately, avoiding dominance effect and providing two distinct scales for aesthetics and satisfaction.

• Mayo Wrist Scores - A tool used to assess wrist function, pain, range of motion, grip strength and the ability to return to normal activities of daily living. The score is from 0 to 100 where 100 indicates a better condition.