BASE OF THUMB ARTHRITIS Flashcards
Stabilisers of thumb CMC joint
Bony vs. soft-tissue or static vs. dynamic
Static stabilisers
1. Bony stability minimal = incongruent biconcave saddle
2. Capsule and ligaments = 4 main ligaments
Volar-ulnar/ anterior oblique/ Beak ligament
- main stabiliser of joint
- volar tubercle of trapezium to volar ulnar aspect of MC base
- degree of attenuation = Eaton-Littler stage
Intermetacarpal ligament
- primary restraint to radial translation of MC base
- base of IF MC to base of thumb MC
Dorsoradial ligament
- primary restraint to dorsal subluxation of MC base
- strongest and thickest ligament
Posterior oblique ligament
Dynamic stabilisers = tendons crossing joint
Volar side = FCR tendon
Dorsal side = APL, EPB and EPL tendons
Thumb movements
4 simple uniplanar vs. 2 complex multiplanar movements
Simple uniplanar movements
1. Flexion = toward IF in plane of palm
2. Extension = away from IF in plane of palm
- also radial abduction
3. Palmar abduction = away from plane of palm
4. Adduction = toward plane of palm
Complex multiplanar movements
1. Opposition (thumb to LF) = abduction and flexion
2. Retropulsion (thumb off table) = abduction and extension
JRF across thumb CMCJ with pinch
JRF across CMCJ is 13x pinch force
3 risk factors for thumb CMCJ arthritis
- Female gender
- Generalised ligament laxity/ hyperlaxity syndrome like EDS
- Increased BMI
Aetiology of thumb CMCJ arthritis
4IT CASH or traumatic vs. atraumatic Traumatic - Fracture = Bennett or Rolando - Ligament injury = Beak ligament disruption - Dislocation Atraumatic - Idiopathic/ primary = most common - Inflammatory
Special radiographic views for thumb CMCJ
- Robert’s view = forearm in hyperpronation with dorsum of thumb flat against cassette
- Bett’s/ Gedda’s view = hand in 30deg pronation
Effect of flexion and extension on thumb CMCJ
Thumb flexion unloads volar aspect of joint
Thumb extension increases load through volar aspect
Volar aspect of joint affected 1st
Explains splinting in abduction and flexion to unload
5 deformities associated with thumb CMCJ arthritis
- Dorsoradial subluxation of MC base
- Thumb adduction
- 1st webspace contracture
- Thumb MP hyperextension to compensate for decreased ROM and to enable grasp = causes attenuation of volar plate
- Thumb IP flexion
Classification of thumb CMCJ arthritis
Eaton and Littler classification = radiographic classification with 4 stages
Stage I = joint space widening due to synovitis
Stage II = some joint space narrowing with small (< 2mm) osteophytes
Stage III = severe joint space narrowing with large (> 2mm) osteophytes
Stage IV = pantrapezial including STT arthritis
Differentials for radial-sided wrist pain
Bony vs. soft-tissue Bony causes 1. Distal radius fracture 2. Scaphoid fracture 3. Perilunate/ lunate dislocation 4. Base of thumb fracture 5. Radiocarpal arthritis 6. SLAC/ SNAC wrist 7. Base of thumb arthritis 8. STT arthritis Soft-tissue causes 1. SL ligament injury 2. FCR tendonitis 3. DeQuervain's tenosynovitis 4. Intersection syndrome 5. SRN neuroma
Main non-operative options with thumb CMCJ arthritis
- NSAIDs
- Physio = abduction and flexion stretches to prevent adduction and extension contractures
- Splinting = abduction and flexion to unload volar joint
- CS injections
2 main groups of surgical options for thumb CMCJ arthritis
Joint preserving/ salvage vs. joint sacrifice
Joint preserving options = Stage I or II
1. CMCJ arthroscopic debridement/ synovectomy
- dorsoradial portal = radial to APL
- dorsoulnar portal = between EPL and EPB
2. Beak ligament reconstruction = Eaton-Littler procedure
3. Metacarpal extension osteotomy (MEO)
Joint sacrificing options = Stage III or IV
1. Excision
2. Arthrodesis
3. Arthroplasty
- silicone, zerconia and condylar implants have poor results
Beak ligament reconstruction (Eaton-Littler procedure): Advantages Disadvantages Indications Contraindications Technique
- Advantages
- joint preservation
- joint stability - Disadvantages
- technically demanding
- prolonged recovery = immobilisation
- complications = failure of reconstruction - Indications
- CMCJ instability
- no arthritis - Contraindications
- CMCJ arthritis - Technique
- FCR or PL tendon graft
- FCR left attached distally to base of IF MC
- passed volarulnar to dorsoradial through base of thumb MC, over APL and sutured back onto itself
- reconstructs 3 of 4 ligaments = anterior oblique, intermetacarpal and dorsoradial ligaments
- 80-90% success rate with Stage I or II disease
Metacarpal extension osteotomy (MEO): Advantages Disadvantages Indications Contraindications Technique
- Advantages
- joint preservation
- unloads volar part of joint
- improves ROM - Disadvantages
- technically demanding
- prolonged recovery = immobilisation
- complications = nonunion - Indications
- early stage (I or II) disease - Contraindications
- involvement of > 1/3 volar joint = Stage III or IV disease
- CMCJ instability
- MP hyperextension deformity > 10deg = needs volar capsulodesis or fusion - Technique
- dorsal closing wedge osteotomy to unload volar aspect of CMCJ and improve ROM
- 80-90% success rate with Stage I or II disease
Trapezectomy (excision arthroplasty): Advantages Disadvantages Indications Contraindications Technique
- Advantages
- technically easier
- faster recovery = no prolonged immobilisation
- lower complication rate - Disadvantages
- theoretical risk of MC subsidence causing pain due to impingement between MC base and scaphoid
- theoretical risk of decreased grip strength - Indications
- late/ advanced/ end stage (III or IV) disease - Contraindications
- CMCJ instability - Technique
- Wagner or dorsal approach
- cruciate osteotomy and piecemeal excision
- assess trapezoid = excise proximal 1/3 if arthritic
- stress MC to assess subsidence = consider LRTI
- radial 1/2 of FCR left intact distally, passed through base of thumb MC and sutured onto itself, excess tendon anchovied and used as spacer
