1st CMC Arthritis Senario

Question 1

Aggravating and Alleviating

Answer 1

1. Aggravating
   
   1. movement
      
      1. writing
      2. turning door knobs or keys
      3. using scissors
      4. opening jars
   2. pinch
2. Alleviating
   
   1. rest
   2. NSAIDs

Question 2

ADLs

Answer 2

1. Handwriting
2. Use of scissors
3. Doorknob use
4. Key use
5. Opening jars

Question 3

Deformity

Answer 3

1. dorsoradial prominence of thumb MC base
   
   1. subluxation
   2. osteophyte
   3. inflammation
2. Adducted posture of thumb

Question 4

Feel

Answer 4

1. TTP - volar, dorsal, or radial CMC joint capsule
2. Palpate joints
   
   1. CMC
   2. MCP
   3. ST – 1 cm proximal to CMC
   4. Do not palpate directly over course of ABPL, EPB to avoid mistaking with deQuervain

Question 5

Move

Answer 5

1. Active and passive
   
   1. IP, MP, basal joints
   2. Compare to other side
2. Assess amount of MC hyperextension during thumb pinch
   
   1. note if hyperextension is painful or painless
3. Check for crepitus
4. Check for adduction contracture
5. Decreased hand spread width
6. Note difference into angle between first and second metacarpal in full palmar abduction and radial deviation compared to other side

Question 6

Special Tests

Answer 6

1. Grind test
   
   1. Rotation with axial compression reproduces pain
2. Assess instability of 1^st CMC
   
   1. increased laxity
      
      1. ? attenuation of volar beak ligament
   2. decreased laxity
      
      1. significant joint degeneration and osteophytes
3. Measure pinch strength
4. Finkelstein test (r/o DeQuervain)
5. check for triggering
6. tinnels
7. phalen test
8. check UCL stabilty

Question 7

Imaging

Answer 7

1. Roberts’ view
   
   1. Full pronation with thumb extension and dorsum on the XR cassette
   2. A true AP of the thumb
2. stress views
   
   1. PA centered on both thumbs
   2. 30 degree oblique
   3. Patient presses opposing thumbs together
3. lateral key pinch view to assess dynamic loss of basal jt height
4. xray findings
   
   1. OA
      
      1. Osteophytes, sclerosis, asymmetric joint narrowing, subchondral cysts
   2. dorsoradial subluxation of 1^st MC base
5. Staging (Eaton)
   
   1. Stage 1
      
      1. Joint contour normal
      2. Joint space may be widened (synovitis)
      3. Mild subluxation
   2. Stage 2
      
      1. Joint contour normal
      2. Slight joint space narrowing
      3. Mild sclerosis
      4. Osteophytes < 2 mm
   3. Stage 3
      
      1. Joint narrowing with sclerotic or cystic changes in subchondral bone
      2. Osteophytes > 2 mm
      3. Scaphotrapezial joint intact
   4. Stage 4
      
      1. Pan trapezial arthritis

Question 8

Diagnosis or DDx

Answer 8

1. Differential Diagnosis
   
   1. De Quervain’s tenosynovitis
   2. MP arthrosis
   3. Intercarpal or radiocarpal arthrosis
   4. Scaphoid nonunion
   5. SRN compression

Question 9

Treatment Goal

Answer 9

• Decreased Pain
• Improvement in grip and pinch strength

Question 10

Non-operative Rx

Answer 10

1. Initial treatment for all stages
2. Activity modification
   
   1. Larger diameter writing tools
   2. Larger diameter golf clubs
   3. Reading stand for books
3. Thumb Spica Splint (prefabricated thermoplastic hand-based splint) X 3-6 weeks
4. NSAIDs X 2-3 weeks
5. Corticosteroid injections
   
   1. XR guided in # clinic
   2. Assistant to apply longitudinal traction to thumb to distract joint
   3. Sterile prep and drape
   4. Dorsoradial injection with 21g needle (40 mg methylprednisolone and 1 cc 2% xylo)

Question 11

Operative

Answer 11

1. Stage 1
   
   1. CMC synovectomy and debridement (arthroscopic)
   2. Metacarpal osteotomy
   3. Ligament reconstruction with FCR in case of joint laxity
2. Stage 2
   
   1. Arthroscopic debridement and tendon interposition
   2. Partial trapeziectomy with tendon interposition
   3. Metacarpal osteotomy
   4. Prosthetic arthroplasty
      
      1. Metallic
      2. Silicone implant contraindicated for active patient with OA
         
         1. dislocation
         2. recurrent pain
         3. synovitis
   5. Complete trapeziectomy and ligament reconstruction and tendon interposition (LRTI)
   6. Trapeziometacarpal arthrodesis
      
      1. Optimal position
         
         1. 30-40 deg of palmar abduction
         2. 35 deg of radial abduction
         3. 15 deg of pronation
      2. reserved for young labourer
      3. resultant limitations
         
         1. inability to lay hand flat
3. Stage 3
   
   1. Partial trapeziectomy with tendon interposition
   2. Prosthetic arthroplasty
   3. Complete trapezoidectomy and ligament reconstruction and tendon interposition (LRTI)
   4. Trapeziometacarpal arthrodesis
4. Stage 4

Complete trapezoidectomy and ligament reconstruction and tendon interposition (LRTI)