MCP joint problems - ulnar drift

aetiology
Effect of RA on MCP joint

Synovitis

·      synovitis with distension of capsule and surrounding structures

·      prediliction for

·      radial collateral with radial laxity

·      radial sagittal band with ulnar subluxation of tendon

Articular destruction

·      erosion of MCP jt with joint collapse

·      esp. under radial collateral

·      leads to relative lengthening of collateral ligaments

·      esp. radial

Compounding factors

Anatomy

·      ulnar interossei stronger than radial interossei

·      ulnar vector of long extensor pull

·      esp. if tendon subluxed ulnarward

Physiology

·      forces act in ulnar direction

·      gravity

·      key pinch

·      power grip

Pathology

·      wrist joint involvement with radial deviation

·      fingers drift ulnarward to compensate

clinical

·      starts with synovitis of MCP joint

·      progressive ulnar drift

·      base of P1 subluxes ulnarward and volarward

·      deformity becomes fixed

·      contracture of ulnar structures and stretching of radial structures

·      wrt. intrinsics, sagittal bands and collaterals

treatment
Synovitis with minimal ulnar drift

MCP synovectomy

·      single joint approached through longitudinal incision

·      multiple joints approached through transverse incision

·      extensor hood incised along ulnar side of long extensor

·      capsule opened longitudinally

·      thorough synovectomy

·      beneath collaterals

·      from recess over volar plate under MC head

Ulnar intrinsic release

·      ulnar interossei divided at MCP joint

·      through sagittal and oblique fibres of extensor expansion on ulnar side of extensor tendon

·      defunction attachment to volar plate and base of proximal phalanx

·      similarly release abductor digiti minimi

Postoperative

·      splint MCPs in extension for 2 weeks

Synovitis with correctable ulnar drift

MCP synovectomy

·      as above

·      radial collateral

·      release radial collateral at origin

·      subsequently reattach proximally and dorsally through drillhole

·      ulnar collateral

·      release if contracted

·      volar plate

·      release from MC neck to restore hyperextension

·      recentre extensor tendon

·      reattach extensor hood with plication of radial sagittal fibres

Crossed intrinsic transfer

·      release ulnar interossei and AbDM

·      transfer to radial side of adjacent digit

·      reinsert through radial lateral band

·      transfer EIP into radial side if significant index drift

Synovitis with fixed ulnar drift and volar subluxation

Interposition arthroplasty

·      MC head resected

·      soft tissue interposed

Volar plate

·      volar plate freed proximally

·      free proximal edge sutured to dorsal lip of MC neck

Silastic arthroplasty

·      enough bone resected from MC head and proximal phalanx base

·      Swanson silicon arthroplasty inserted

Soft tissue reconstruction

·      as above

Interphalangeal joints

synovitis
Clinical

·      pain and swelling of IP joint

·      limitation of active and passive movement

Treatment

·      dorsomedial incision

·      synovectomy

·      careful closure of capsule and reconstitution of extensor apparatus

Ankylosis
Clinical

·      stiff joint in abnormal position

Treatment

Arthrodesis

·      dorsomedial incision

·      extensor apparatus and capsule split in midline

·      collateral ligaments divided

·      base of middle phalanx cut off square

·      head of proximal phalanx cut off obliquely

·      aim for flexion of

·      PIP jt - 10o for 2nd, 20o for 3rd, 30o for 4th, 40o for 5th

·      DIP jt - 10o

·      stabilise with crossed K wires

·      capsule and extensor expansion reconstituted

Arthroplasty

·      silicone implant

·      extensor reconstruction as below

instability
Clinical

·      loss of ligamentous support

·      joint flail

Treatment

·      arthrodesis or arthroplasty as above

boutonniere deformity

·      consists of

·      PIP flexion (primary)

·      DIP and MCP hyperextension (secondary)

Aetiology

·      PIP synovitis stretches central slip

·      leads to PIP jt flexion

·      lateral bands displace volarward and become fixed

·      lateral bands exert undue extensor force across DIP jt

·      DIP jt lapses into hyperextension

·      MCP hyperextends to compensate for PIP flexion

·      deformity becomes fixed

·      PIP flexion - volar plate contracts

·      DIP hyperextension - oblique retinacular fibres contract

Clinical

Mild

·      slight lag in PIP jt extension

·      correctable passively

·      PIP extension limits DIP jt flexion

Moderate

·      significant PIP jt flexion deformity

·      still correctable passively

·      secondary DIP and MCP hyperextension

Severe

·      PIP jt flexion cannot be corrected passively

Treatment

Mild

·      tenotomy of terminal slip to improve DIP jt flexion

Moderate

·      shortening of central slip and dorsal reduction of lateral bands

·      dorsomedial incision

·      lateral bands separated from central slip

·      synovectomy of PIP jt performed

·      5 mm of central slip resected and tendon repaired

·      transverse retinacular bands released volar to lateral bends

·      lateral bands brought dorsally and sutured to each other

·      tenotomy of terminal slip to improve DIP jt flexion

·      K-wire across PIP jt to maintain full extension

Severe

·      joint preserved

·      extensive release to restore extension

·      reconstruction as above

·      joint destroyed

·      PIP arthroplasty

·      PIP arthrodesis

swan neck deformity
Aetiology

Synovitis

·      most common

·      primary PIP jt involvement

·      laxity of volar plate and PIP jt hyperextension

·      weakening of lateral band support and dorsal subluxation of lateral bands

·      primary MCP jt involvement

·      weaking of capsular support and MCP volar subluxation

·      intrinsic shortness and contracture

Other

·      rupture of terminal slip (mallet finger)

·      allows dorsal subluxation of lateral bands

·      rupture of FDS tendon

·      removes force restraining PIP hyperextension

Classification

·      may cause significant functional loss

·      related to loss of motion at PIP jt

·      classified according to

·      PIP jt flexion

·      status of PIP jt

Flexible PIP jt

·      due to stretching of PIP jt volar plate with PIP jt hyperextension

·      may be precipitated by

·      rupture of terminal slip with mallet finger

·      rupture of FDS with increased hyperextension

Treatment

Flexor tenodesis

·      when PIP jt synovitis primary

·      Brunner incision

·      flexor tendons exposed

·      one slip of FDS divided 1.5 cm proximal to PIP jt

·      left attached distally

·      PIP jt flexed 30o

·      detached slip advanced proximally

·      passed through slit in A2 pulley and sutured back on itself

DIP fusion

·      when mallet deformity primary

·      fused with

·      crossed K wires

·      cerclage wire

·      Herbert screw

Partial limitation PIP jt flexion

·      flexion limited by tightness of ulnar intrinsics

·      demonstrated with Bunnell test

·      PIP jt flexion limited with MCP jt extension and radial deviation

·      flexion restored with MCP jt flexion and ulnar deviation

·      may be MCP jt volar subluxation

Treatment

·      relief of intrinsic tightness

·      may need to address MCP jts

Intrinsic release

·      dorsomedial incision over PIP jt

·      longitudinal incision in ulnar sagittal band

·      oblique fibres released

MCP arthroplasty

·      with associated MCP jt involvement

Fixed PIP jt flexion

·      contracture of

·      extensor mechanism

·      collateral ligaments

·      intrinsics

·      skin

·      may be flexor tenosynovitis

Treatment

·      restore passive ROM

·      address flexor tendons

Intrinsic release

·      as above

Lateral band mobilisation

·      lateral bands freed from central slip with two parallel longitudinal incisions

Manipulation

·      gentle MUA of PIP jts

Flexor synovectomy

·      if active ROM less than passive ROM

Stiff PIP jt with destruction

·      treat with

·      PIP arthroplasty

·      PIP arthrodesis

Thumb

boutonniere

·      Nalebuff type 1

·      Z deformity

·      MCP jt flexion and IP jt hyperextension

Aetiology

·      synovitis of MCP jt

·      extensor hood stretched

·      EPL tendon displaced ulnarward and volarly

Treatment

Synovectomy of MCP jt and EPL transfer

·      for early deformity

·      longitudinal dorsomedial incision from MCP jt to IP jt

·      EPL split longitudinally

·      ulnar 1/2 detached proximally

·      distal end remains attached to adductor pollicis

·      radial 1/2 detached distally and mobilised

·      synovectomy of MCP jt performed

·      radial EPL passed through drillhole in base of P1

·      sutured to itself with MCP jt in full extension

·      extensor hood reconstructed with EPB and ulnar EPL

Arthrodesis

·      for unstable MCP jt

·      IP jt may also be unstable

·      use cerclage wire and oblique K wire

swan neck

·      Nalebuff type 3

Aetiology

·      disease at CMC jt

·      leads to dorsal and radial subluxation of jt

·      result is adduction contracture

·      secondary MCP jt hyperextension occurs if volar plate lax

Treatment

Mild

·      interposition arthroplasty of CMC jt

·      may require MCP jt arthrodesis

Technique

·      zigzag incision from proximal 1/3 of MC along 1st extensor compartment

·      radial NV structures protected

·      CMC jt and scaphotrapezial jt opened

·      trapezium removed piecemeal

·      PL harvested

·      folded into anchovy and inserted in space

Severe

·      CMC and MCP arthrodesis