Rhizarthrosis (Thumb Osteoarthritis): Symptoms and Treatment

Rhizarthrosis (thumb osteoarthritis)

Rhizarthrosis is osteoarthritis of the trapeziometacarpal joint, located at the base of the thumb. It is one of the most frequent and debilitating forms of hand osteoarthritis, as the thumb participates in approximately 50% of the hand’s gripping functions. Rhizarthrosis predominantly affects women after 50 years of age, with a radiographic prevalence exceeding 30% in women over 60. Pain at the base of the thumb during daily activities (opening jars, turning keys, writing) is the most characteristic symptom.

Table of Contents

• Anatomy of the Trapeziometacarpal Joint
• Causes and Risk Factors
• Stages of Rhizarthrosis (Eaton-Littler Classification)
• Symptoms
• Diagnosis
• Conservative Treatment
• Physiotherapy and Rehabilitation
• Surgical Treatment
• Recovery Times
• Prevention and Practical Tips
• Frequently Asked Questions (FAQ)
• Frequently Asked Questions
• Resources
• Sources and Scientific References

Anatomy of the Trapeziometacarpal Joint

The trapeziometacarpal (TMC) joint is a saddle joint that connects the first metacarpal to the trapezium bone of the carpus. This unique conformation allows the thumb movements on multiple planes:

• Flexion-extension
• Abduction-adduction
• Opposition: the most important movement, which allows the thumb to touch the tips of the other fingers
• Circumduction: combination of the previous movements

The stability of the joint is guaranteed by a complex ligamentous system:

• Anterior oblique ligament (beak ligament): the most important for stability; its degeneration is considered the initial factor in rhizarthrosis
• Dorsal radial ligament
• Intermetacarpal ligament (between the first and second metacarpals)
• Posterior oblique ligament

The TMC joint is subjected to enormous compressive forces during gripping activities: the forces acting on the base of the thumb during a pinch grip can reach values up to 12 times the force applied by the fingers.

Causes and Risk Factors

Cartilage degeneration

As in all forms of osteoarthritis, the process begins with the degeneration of articular cartilage, which loses its ability to cushion and distribute loads. In the case of rhizarthrosis, laxity of the anterior oblique ligament causes dorsal subluxation of the first metacarpal, increasing the load on reduced articular surfaces and accelerating cartilage wear.

Main risk factors

Female sex: women are affected 10-15 times more frequently than men, probably due to:

• Smaller TMC joint with less congruence
• Greater ligamentous laxity
• Hormonal influences (estrogen decline in menopause)

Age: incidence progressively increases after 40 years of age

Genetic predisposition: family history of hand osteoarthritis

Repetitive mechanical stress: work or hobby activities that require repeated forceful gripping with the thumb (sewing, gardening, manual labor)

Joint hypermobility: generalized ligamentous laxity

Previous trauma: fractures or dislocations of the base of the thumb

Stages of Rhizarthrosis (Eaton-Littler Classification)

Symptoms

Pain

• Location: at the base of the thumb, in the “anatomical snuffbox” or slightly more palmar
• Characteristics: dull pain that worsens with use and improves with rest
• Provoking activities: opening jars, turning keys, unscrewing caps, sewing, writing, using scissors
• Evolution: initially intermittent, progressively becomes more constant

Stiffness

• Reduced opposition and abduction movement of the thumb
• Morning stiffness generally lasting less than 30 minutes (unlike rheumatoid arthritis)
• Progressive difficulty fully opening the hand

Deformity

• Dorsal subluxation: the base of the first metacarpal protrudes dorsally, creating a visible prominence
• “Z” deformity of the thumb: hyperextension of the metacarpophalangeal joint and flexion of the interphalangeal joint as compensation for TMC subluxation
• Thenar eminence atrophy: reduction of the musculature at the base of the thumb in advanced stages

Loss of function

• Reduced grip strength (up to 50-80% in advanced stages)
• Difficulty with daily activities: dressing, cooking, writing
• Inability to perform fine pinch grips
• Joint crepitus during movement

Diagnosis

Clinical examination

• Axial compression test (grind test): compression and rotation of the first metacarpal on the trapezium — positive if it causes pain and crepitus
• Lateral stress test: instability in abduction-adduction
• Palpation: pain on pressure over the TMC
• Mobility assessment: limitation of opposition and abduction
• Grip strength: measured with a dynamometer, compared to the opposite side

Instrumental examinations

• Radiography: first-level examination, shows narrowing of joint space, osteophytes, subluxation, and sclerosis. Robert’s projection (true anteroposterior of the TMC) for accurate evaluation
• Ultrasound: assesses synovitis, effusion, ligament integrity
• Magnetic resonance imaging: useful in early stages when radiography is normal, shows bone edema, cartilage and ligament involvement
• CT scan: rarely necessary, useful for surgical planning

Conservative Treatment

Conservative treatment is the first choice in stages I-III and can provide significant symptom relief in most patients.

Splint

The TMC splint is the cornerstone of conservative treatment:

• Resting splint: immobilizes the TMC while leaving the fingers free, to be worn at night and during flare-ups
• Functional splint: maintains the TMC in the correct position while partially allowing movements, ideal for daily activities
• Duration: at least 3-6 months of regular use to assess efficacy
• Efficacy: 50-70% pain reduction in many patients

Medications

• Topical NSAIDs: diclofenac or ketoprofen gel on the base of the thumb (effective and with fewer side effects than oral NSAIDs)
• Oral NSAIDs: for short periods during flare-ups
• Paracetamol: as a basic analgesic
• Corticosteroid injections: intra-articular injection into the TMC, temporary efficacy (weeks-months)
• Hyaluronic acid injections: viscosupplementation, promising results but still limited evidence

Instrumental physical therapy

• Laser therapy: pain and inflammation reduction
• Therapeutic ultrasound: stimulation of local metabolism
• Paraffin therapy: warm paraffin baths for stiffness and pain
• Tecar therapy: tissue biostimulation

Physiotherapy and Rehabilitation

Rehabilitation is fundamental both in conservative treatment and after surgical intervention.

Phase 1 — Protection and pain management (weeks 1-4)

Therapeutic education:

• Joint protection: teach gripping techniques that reduce stress on the TMC
• Use ergonomic, enlarged handles for tools and pens
• Distribute the load over multiple fingers instead of concentrating it on the thumb
• Avoid prolonged lateral pinch grips

Thermotherapy:

• Warm hand baths (10-15 minutes) before exercises
• Application of ice after activities that cause pain

Gentle mobilization:

• Flexion-extension movements of the TMC within the pain-free range
• Slow and controlled thumb circumduction
• Self-mobilization of the first web space (space between thumb and index finger)

Phase 2 — Stabilization and strengthening (weeks 4-12)

TMC stabilization exercises:

• Pinch grip with soft therapeutic putty (10 repetitions, 3 sets)
• Thumb opposition to each finger with light elastic resistance
• Thumb abduction against resistance of a thin elastic band
• Isometric exercise: press the thumb against the side of the index finger, holding for 5 seconds

Thenar musculature strengthening:

• Exercises with balls of different resistance (squeeze ball)
• Thumb extension against elastic band (extensor strengthening)
• Radial abduction against resistance (long abductor strengthening)

Global hand strengthening:

• Grip with light-medium resistance hand grip
• Fine manipulation exercises (picking up small objects, turning coins)
• Use of therapeutic putty for all hand movements

Phase 3 — Functionality and prevention (from 3 months onwards)

• Resumption of daily activities with joint protection techniques
• Maintenance of exercises 3-4 times a week
• Continuous use of the splint during stressful activities
• Adaptation of work tools and household utensils

Surgical Treatment

Surgery is indicated when conservative treatment of at least 6 months does not provide adequate pain relief, in stages III-IV with significant deformity and functional loss.

Main surgical techniques

Trapeziectomy (with or without suspension arthroplasty):

• Removal of the trapezium bone, with possible ligament reconstruction using a tendon (e.g., flexor carpi radialis)
• Most commonly used technique, excellent long-term results for pain
• May result in slight reduction of grip strength

Arthrodesis (joint fusion):

• Fusion of the TMC in a functional position
• Indicated in young, active patients with high functional demands
• Eliminates pain but sacrifices TMC mobility

Trapeziometacarpal prosthesis:

• Implantation of an artificial joint
• Variable results, risk of loosening over time

Post-surgical rehabilitation

• Weeks 0-4: fixed splint, long finger movements allowed
• Weeks 4-6: progressive splint removal, active assisted mobilization
• Weeks 6-10: progressive strengthening, increased hand use
• Months 3-6: gradual return to activities with full functionality
• Full strength recovery generally requires 4-6 months

Recovery Times

Prevention and Practical Tips

Daily ergonomics

• Use enlarged handles on pens, cutlery, kitchen utensils
• Prefer jars with wide screw caps or use a jar opener
• Use spring-loaded scissors that open automatically
• Open doors with the palm of the hand rather than with a pinch grip on the handle
• Distribute the weight of objects over both hands

Joint protection

• Avoid prolonged lateral pinch grips (e.g., holding a key or paper between thumb and index finger for a long time)
• Use both hands to lift pots and plates
• Purchase utensils with ergonomic and non-slip handles
• Wear the splint during activities that stress the thumb

Maintenance exercises

• Thumb mobilization every morning (5 minutes)
• Light strengthening exercises with putty 3 times a week
• Warm hand baths before exercises

Frequently Asked Questions (FAQ)

Frequently Asked Questions

Can rhizarthrosis affect both hands?

Rhizarthrosis can indeed affect both hands, although the severity and onset may differ between them. It is common for osteoarthritis to manifest bilaterally, impacting daily activities requiring fine motor skills in both thumbs.

Can rhizarthrosis be prevented?

While complete prevention of rhizarthrosis may not be possible due to genetic and age-related factors, certain strategies can help mitigate its progression. Adopting ergonomic practices, protecting the joints from excessive stress, and performing maintenance exercises are recommended.

Should the splint be worn constantly?

The recommended duration for wearing a splint for rhizarthrosis varies based on individual symptoms and the stage of the condition. A healthcare professional typically provides specific guidance on when and how long to wear the splint to optimize pain relief and joint support.

Is full functionality recovered after surgery?

Surgical intervention for rhizarthrosis aims to significantly improve pain and restore a substantial degree of thumb function. Post-surgical rehabilitation with a physical therapist is crucial for optimizing recovery and regaining strength and mobility. While significant improvement is expected, the extent of functional recovery can vary among individuals.

Sources and Scientific References

1. Chevalier X et al. (2012). [Rhizarthrosis]. Rev Prat. 62:639. PubMed
2. Falkner F et al. (2022). [Conservative treatment options for symptomatic thumb trapeziometacarpal joint osteoarthritis]. Orthopade. 51:2-8. DOI | PubMed
3. Messina A (2000). [Vascularized surgical rotation of a bi-articular trapezoid-trapeziometacarpal complex for the treatment of severe rhizarthrosis of the thumb]. Chir Main. 19:134-40. DOI | PubMed
4. Van Innis F et al. (1983). [Trapeziectomy in rhizarthrosis]. Ann Chir Main. 2:365-7. DOI | PubMed
5. Corain M et al. (2025). The Use of Collagen-Based Filler for Trapeziometacarpal Osteoarthritis: Long-Term Follow-Up and Future Applications. Cartilage.:19476035251354926. DOI | PubMed