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Not affiliated with the Royal Australasian College of Surgeons.

Midcarpal Arthritis

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Hand & Upper Limb

Midcarpal Arthritis

Comprehensive examination guide to midcarpal arthritis patterns, diagnostic evaluation, and surgical management including limited wrist fusions and total wrist arthroplasty

complete
Updated: 2026-01-02
High Yield Overview

Midcarpal Arthritis

Degenerative arthritis of the midcarpal joint, commonly from SLAC/SNAC patterns

Most common degenerative wrist patternSLAC wrist
75-80% grip, 50-60% motion preservedFour-corner fusion
70-75% grip, faster recovery, requires pristine cartilagePRC

Critical Must-Knows

  • Differentiate midcarpal from radiocarpal arthritis - different surgical solutions
  • SLAC wrist progresses through three stages (Stage I radial styloid, II scaphoid fossa, III midcarpal)
  • Four-corner fusion preserves 60% wrist motion with 80% grip strength
  • Proximal row carpectomy requires intact lunate fossa cartilage
  • Total wrist fusion position: 10-15 degrees extension, 5-10 degrees ulnar deviation

Examiner's Pearls

  • "
    Know Lichtman SLAC staging system and which stages amenable to motion-preserving surgery
  • "
    Describe physical examination findings: midcarpal shift test, Watson test
  • "
    Explain why scaphoid excision necessary in four-corner fusion
  • "
    Discuss fixation options for four-corner fusion: headless screws vs circular plate vs Spider plate
  • "
    Know contraindications to PRC: lunate fossa arthritis, capitate chondromalacia, inflammatory arthritis

Exam Warning

SLAC Wrist Staging is Essential: Stage I = radial styloid arthritis (radial styloidectomy), Stage II = scaphoid fossa arthritis (consider scaphoid excision + four-corner fusion), Stage III = midcarpal arthritis (four-corner fusion or PRC). Stage IV adds DRUJ arthritis (consider total wrist fusion). Knowing stages determines surgical options.

At a Glance

Midcarpal arthritis affects the articulation between proximal and distal carpal rows, most commonly from SLAC (scapholunate advanced collapse) or SNAC (scaphoid nonunion advanced collapse) wrist patterns. Know the Lichtman SLAC staging: Stage I (radial styloid), Stage II (scaphoid fossa), Stage III (midcarpal), Stage IV (pancarpal with DRUJ). Four-corner fusion (scaphoid excision + capitate-hamate-lunate-triquetrum fusion) is the workhorse procedure, preserving 60% wrist motion with 80% grip strength. Proximal row carpectomy is an alternative requiring intact lunate fossa cartilage. Critical concept: the radiolunate joint remains preserved until late disease - this is why scaphoid excision works.

Mnemonic

RAMSSLAC Wrist Stages - RAMS

R
R - Radial styloid arthritis (Stage I)
A
A - Articulation scaphoid fossa arthritis (Stage II)
M
M - Midcarpal arthritis capitate-lunate-hamate (Stage III)
S
S - Stage IV adds pancarpal with DRUJ involvement

Memory Hook:RAMS helps remember SLAC progression - think of RAM pushing through the wrist stages

Mnemonic

CARTILAGEPRC vs Four-Corner Fusion Decision - CARTILAGE

C
C - Cartilage lunate fossa must be pristine (Grade I-II only)
A
A - Age favors older patients for PRC (greater than 50)
R
R - Reliability slightly favors 4CF for strength
T
T - Time to recovery faster with PRC
I
I - Inflammatory arthritis contraindication to PRC
L
L - Low demand patients better PRC candidates
A
A - Arthritis progression risk higher with PRC
G
G - Grip strength 5-10% better with 4CF
E
E - Early mobilization advantage PRC

Memory Hook:CARTILAGE quality determines PRC suitability - perfect mnemonic for cartilage-dependent procedure

Mnemonic

CLTDFour-Corner Fusion Bones - CLTD

C
C - Capitate
L
L - Lunate
T
T - Triquetrum
D
D - Distal (Hamate)

Memory Hook:Remember CLTD like CLT Down to recall the four bones fused

Overview and Epidemiology

Midcarpal arthritis represents a complex pattern of wrist degeneration affecting the articulation between the proximal carpal row (scaphoid, lunate, triquetrum) and distal carpal row (trapezium, trapezoid, capitate, hamate). Unlike radiocarpal arthritis which affects the radius-carpal interface, midcarpal arthritis frequently results from chronic carpal instability patterns, particularly scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC).

The surgical management of midcarpal arthritis has evolved significantly over the past three decades. Motion-preserving procedures including four-corner fusion and proximal row carpectomy offer alternatives to total wrist arthrodesis in appropriately selected patients. Understanding the patterns of arthritis progression, patient factors affecting procedure selection, and technical nuances of each operation is essential for optimal outcomes.

Epidemiology

  • SLAC wrist: Most common degenerative wrist pattern
  • Prevalence increases with age
  • Male predominance (3:1)
  • Often bilateral involvement (30%)
  • Scaphoid nonunion present in 50% trauma cases
  • Inflammatory arthritis affects 70% RA patients

Pathophysiology

  • Loss of normal carpal kinematics
  • Progressive articular cartilage degeneration
  • Subchondral sclerosis and cyst formation
  • Osteophyte formation
  • Synovial inflammation variable
  • Capsular contracture develops

Natural History

  • SLAC progression over 10-20 years
  • Pain typically precedes radiographic changes
  • Function declines with advancing stage
  • Grip strength reduced 40-60%
  • Motion limitation variable
  • Spontaneous fusion rare

Etiology and Classification

SLAC Wrist Progression

Scapholunate advanced collapse represents the most common pattern of degenerative wrist arthritis. The condition results from chronic scapholunate dissociation leading to predictable pattern of cartilage loss.

Classification

Lichtman SLAC Staging:

  • Stage I: Arthritis between scaphoid and radial styloid

    • Radial styloid beaking
    • Preserved scaphoid fossa
    • Treatment: Radial styloidectomy

  • Stage II: Arthritis entire scaphoid fossa (radioscaphoid joint)

    • Scaphoid fossa cartilage loss
    • Capitate migrates proximally
    • Treatment: Four-corner fusion vs PRC

  • Stage III: Midcarpal arthritis (capitate-lunate)

    • Preserved radiolunate joint (key feature)
    • Hamate-triquetrum involvement
    • Treatment: Four-corner fusion vs PRC

  • Stage IV: Pancarpal arthritis including radiolunate

    • DRUJ arthritis common
    • Motion-preservation not possible
    • Treatment: Total wrist arthrodesis

SNAC Wrist Pattern

Scaphoid nonunion advanced collapse follows identical progression to SLAC but initiates from scaphoid fracture nonunion rather than ligament injury.

Key Differences from SLAC:

  • History of scaphoid fracture
  • Scaphoid proximal fragment remains attached to lunate
  • Distal fragment rotates into flexion
  • Same radiographic staging system applies
  • Same surgical treatment algorithm

Other Etiologies

Post-Traumatic:

  • Perilunate dislocation sequelae
  • Trans-scaphoid perilunate fracture-dislocation
  • Axial loading injuries
  • Distal radius malunion

Inflammatory:

  • Rheumatoid arthritis (70% wrist involvement)
  • Psoriatic arthritis
  • Systemic lupus erythematosus
  • Crystal arthropathy (gout, pseudogout)

Degenerative:

  • Primary osteoarthritis (rare in wrist)
  • Kienbock disease (avascular necrosis lunate)
  • Preiser disease (avascular necrosis scaphoid)

Clinical Assessment

History and Physical Examination

Patients typically present with chronic wrist pain, stiffness, and functional limitation. Distinguishing midcarpal from radiocarpal pathology clinically guides imaging and treatment planning.

Key History Elements:

  • Pain location: Dorsal midcarpal vs radial styloid
  • Onset: Acute injury vs insidious progression
  • Mechanical symptoms: Catching, clicking, giving way
  • Functional limitation: Grip strength, keyboard use, weight-bearing
  • Prior treatment: Injections, splinting, therapy
  • Occupational demands: Labor vs sedentary

Physical Examination Findings:

Inspection:

  • Dorsal prominence from carpal collapse
  • Muscle atrophy (late finding)
  • Skin condition (plan incisions)
  • Prior surgical scars

Palpation:

  • Point tenderness over scapholunate interval
  • Midcarpal joint line tenderness
  • Radial styloid tenderness (Stage I SLAC)
  • DRUJ stability and tenderness

Range of Motion:

  • Flexion-extension arc (compare to contralateral)
  • Radial-ulnar deviation
  • Forearm rotation
  • Measure and document baseline

Special Tests:

  • Watson test (scaphoid shift): Positive with SL instability
  • Midcarpal shift test: Clunk with ulnar to radial deviation
  • Shear test: Pain with axial loading
  • Grip strength: Typically 40-60% reduction

Exam Pearl

Midcarpal Shift Test Technique: Stabilize the proximal carpal row dorsally with one hand. With the other hand, grasp the metacarpals and translate the distal row palmarly. A palpable clunk indicates midcarpal instability. Perform wrist in neutral, then in ulnar and radial deviation. Positive test suggests capitolunate instability or midcarpal pathology.

Imaging Studies

Plain Radiographs (Essential):

Standard wrist series including PA, lateral, and bilateral clenched-fist views.

PA View Findings:

  • Scapholunate interval widening (greater than 3mm)
  • Scaphoid ring sign (flexed scaphoid)
  • Radial styloid beaking
  • Joint space narrowing
  • Subchondral sclerosis and cysts
  • Osteophyte formation

Lateral View Findings:

  • Scapholunate angle (normal 30-60°, DISI greater than 70°)
  • Radiolunate angle (normal 0±10°)
  • Carpal height ratio (Revascularization Index less than 0.5 abnormal)
  • Capitate migration (proximal relative to radius)

Clenched-Fist PA View:

  • Accentuates scapholunate gap
  • Dynamic instability assessment
  • Comparison to relaxed PA view

Advanced Imaging:

CT Scan:

  • Detailed assessment of arthritis extent
  • Preoperative planning for four-corner fusion
  • Evaluate lunate fossa cartilage (PRC planning)
  • Assess subchondral bone quality
  • 3D reconstruction for complex cases

MRI:

  • Soft tissue assessment (rarely needed for arthritis)
  • Evaluate ligament integrity in early disease
  • Rule out avascular necrosis
  • Assess for concurrent pathology

Wrist Arthroscopy:

  • Gold standard for cartilage assessment
  • Can perform limited debridement
  • Confirm staging before definitive surgery
  • Identify salvageable joints

Non-Operative Management

Initial treatment focuses on symptom control and functional optimization. Many patients achieve acceptable outcomes avoiding surgery.

Conservative Modalities

Splinting:

  • Wrist immobilization splint for acute flares
  • Custom thermoplast orthosis for activity
  • Night splinting for pain control
  • Typically 4-6 weeks trial

Medications:

  • NSAIDs first-line for pain control
  • Acetaminophen for mild symptoms
  • Topical diclofenac gel
  • Avoid long-term narcotic use

Corticosteroid Injection:

  • Midcarpal injection under ultrasound or fluoroscopy
  • Triamcinolone 40mg mixed with local anesthetic
  • Relief typically 3-6 months
  • Limit to 3 injections per year
  • Can help confirm pain generator

Physical Therapy:

  • Gentle range of motion exercises
  • Strengthening when pain permits
  • Activity modification training
  • Ergonomic optimization
  • Limited efficacy in advanced arthritis

Activity Modification:

  • Avoid heavy lifting and impact loading
  • Keyboard ergonomics
  • Job modification when possible
  • Adaptive equipment for ADLs

Indications for Surgery

Surgical intervention considered when conservative measures fail to provide acceptable symptom control or function.

Absolute Indications:

  • Severe pain limiting ADLs despite 6 months conservative therapy
  • Progressive deformity
  • Functional impairment affecting occupation/quality of life

Relative Indications:

  • Moderate pain with imaging showing advanced arthritis
  • Patient preference after understanding options
  • Young patient with high functional demands

Timing Considerations:

  • Delay surgery until conservative measures exhausted
  • Consider patient age and occupation
  • Assess expectations and compliance potential
  • Coordinate with other medical conditions

Surgical Options Overview

Multiple surgical procedures address midcarpal arthritis. Selection depends on arthritis extent, patient factors, and surgeon experience.

Surgical Procedures for Midcarpal Arthritis

procedureindicationmotionPreservationgripStrengthadvantagesdisadvantages
Radial StyloidectomySLAC/SNAC Stage I only100% preserved90-95% preservedSimple, preserves anatomy, low morbidityOnly for Stage I, progression possible
Four-Corner FusionSLAC/SNAC Stage II-III50-60% arc75-80% normalReliable pain relief, preserves motion, proven outcomesTechnical demanding, nonunion 5-10%, scaphoid excision required
Proximal Row CarpectomySLAC/SNAC Stage II-III, low demand50-60% arc70-75% normalSingle-stage, no implants, lower nonunion riskRequires intact lunate fossa, progression possible, lower strength
Total Wrist ArthrodesisStage IV, salvage, high demand0% (complete fusion)85-90% normalDefinitive, reliable pain relief, maximum strengthLoss of all motion, impacts ADLs, adjacent joint stress
Total Wrist ArthroplastyPan-arthritis low demand60-80% arc60-70% normalPreserves motion, bilateral procedures possibleImplant failure risk, infection, loosening, revision difficult

Four-Corner Fusion

The workhorse procedure for SLAC/SNAC Stage II-III arthritis. Excision of scaphoid eliminates radioscaphoid arthritis while fusing the remaining midcarpal joints preserves the radiolunate articulation.

Four-Corner Fusion Indications:

Ideal Candidate:

  • SLAC or SNAC Stage II or III
  • Preserved radiolunate cartilage
  • Age 30-70 years
  • Moderate to high functional demands
  • Failed conservative treatment minimum 6 months
  • Willing to accept limited postoperative immobilization

Patient Factors Favoring 4CF:

  • Manual laborer requiring grip strength
  • Active patient desiring motion preservation
  • Younger patient (vs total wrist fusion)
  • Desire to avoid complete wrist fusion

Contraindications:

  • Stage IV with radiolunate arthritis
  • DRUJ arthritis (consider total wrist fusion)
  • Active infection
  • Avascular necrosis lunate (Kienbock)
  • Severe osteoporosis
  • Poor bone quality preventing fixation

Relative Contraindications:

  • Inflammatory arthritis (higher nonunion risk)
  • Smoking (counsel cessation minimum 6 weeks)
  • Workers compensation (controversial)
  • Unrealistic expectations

The procedure achieves pain relief in 80-90% of patients while preserving functional wrist motion and grip strength superior to total wrist arthrodesis.

Four-Corner Fusion Technique:

Preoperative Planning:

  • Confirm radiolunate cartilage preservation on CT
  • Assess bone quality
  • Select fixation method (screws vs plate)
  • Counsel patient on 8-12 week immobilization
  • Arrange postoperative therapy

Patient Positioning:

  • Supine with arm board
  • Tourniquet on upper arm
  • Fluoroscopy available

Surgical Approach:

  • Dorsal longitudinal incision centered over Lister tubercle
  • Identify and protect superficial radial nerve branches
  • Elevate extensor retinaculum in ulnar-based flap
  • Incise dorsal capsule exposing midcarpal joint
  • Preserve blood supply to carpal bones

Scaphoid Excision:

  • Identify scaphoid borders
  • Excise scaphoid piecemeal with rongeurs
  • Remove completely to prevent impingement
  • Preserve radial styloid (controversially can excise 2-3mm)
  • Inspect radiolunate cartilage quality
  • Confirm no radial styloid impingement with wrist motion

Joint Preparation:

  • Denude cartilage from capitate, hamate, lunate, triquetrum
  • Achieve congruent bleeding bony surfaces
  • Avoid excessive bone removal
  • Maintain carpal height
  • Fish-scale technique with curets and burrs

Reduction and Fixation:

  • Reduce wrist in neutral flexion-extension
  • Slight radial deviation acceptable
  • K-wire temporary fixation
  • Confirm fluoroscopic alignment (lateral SL angle less than 70°)

Fixation Options:

  1. Headless Compression Screws:

    • 2-4 screws crossing fusion mass
    • Capitate to lunate (central)
    • Capitate to hamate
    • Triquetrum to hamate
    • Optional: Lunate to triquetrum

  2. Dorsal Circular Plate:

    • Spider plate or similar
    • Rigid construct
    • Allows early mobilization (controversial)
    • Prominence may require removal

  3. Locking Plate Technology:

    • Newer designs
    • Potentially lower profile
    • Limited long-term data

Closure:

  • Copious irrigation
  • Ensure no scaphoid fragments remain
  • Repair capsule if possible
  • Retinaculum repair
  • Skin closure
  • Well-padded short-arm splint

Key Technical Points:

  • Complete scaphoid excision prevents impingement
  • Thorough cartilage removal to bleeding bone essential for union
  • Neutral alignment prevents impingement
  • Rigid fixation improves union rates

This detailed technique description demonstrates surgical understanding expected in viva examinations.

Four-Corner Fusion Rehabilitation:

Immediate (0-2 Weeks):

  • Well-padded short-arm splint
  • Elevation to reduce swelling
  • Finger ROM exercises (MCP, IP joints)
  • Shoulder and elbow ROM
  • Pain control
  • First clinic visit 10-14 days for wound check

Early (2-8 Weeks):

  • Transition to removable short-arm cast/splint
  • Continue immobilization
  • Serial radiographs every 4 weeks
  • Monitor for complications
  • No formal therapy yet

Intermediate (8-12 Weeks):

  • Radiographic assessment of fusion
  • If early union signs: begin gentle AROM
  • Hand therapy referral
  • Continue protection for heavy activities
  • Progressive strengthening begins

Late (3-6 Months):

  • Full unrestricted ROM exercises
  • Progressive resistance strengthening
  • Return to unrestricted activities when fusion solid
  • Final radiographic confirmation of union
  • Assess outcomes (pain, function, satisfaction)

Expected Timeline:

  • Radiographic union: 12-16 weeks (70-80% cases)
  • Return to sedentary work: 6-8 weeks
  • Return to manual labor: 4-6 months
  • Final outcome assessment: 12 months

Long-term Follow-up:

  • Annual radiographs years 1-3
  • Monitor for adjacent joint arthritis
  • Hardware removal if symptomatic (10-15% plates)
  • Lifelong activity awareness

This progressive rehabilitation protocol balances fusion protection with functional recovery and represents standard postoperative management.

Four-Corner Fusion Outcomes:

Motion Results:

  • Flexion-extension arc: 50-60% contralateral wrist
  • Average arc: 70-80 degrees total
  • Radial-ulnar deviation: 40-50% preserved
  • Supination-pronation: Maintained

Strength Results:

  • Grip strength: 75-80% contralateral
  • Pinch strength: 85-90% contralateral
  • Progressive improvement to 12 months
  • Maximal strength 18-24 months

Patient-Reported Outcomes:

  • DASH score improvement: 30-40 points
  • Pain VAS reduction: 6-7 points (0-10 scale)
  • Satisfaction: 80-85%
  • Return to work: 90-95%

Complications:

Nonunion (5-10%):

  • Risk factors: Smoking, inflammatory arthritis, poor bone quality
  • Often asymptomatic if stable
  • Symptomatic nonunion requires revision fusion or wrist arthrodesis
  • CT scan best imaging modality

Hardware Complications (10-20%):

  • Plate/screw prominence
  • Extensor tendon irritation
  • Hardware removal required 10-15%
  • Plan for possible second procedure

Impingement (5-10%):

  • Incomplete scaphoid excision
  • Radial styloid prominence
  • Requires revision surgery
  • Radiographic assessment important

Loss of Reduction:

  • Fixation failure
  • Progressive collapse
  • May require revision to total wrist fusion

Other Complications:

  • Infection: 1-2%
  • CRPS: 2-5%
  • Stiffness: Variable
  • Adjacent joint arthritis: Long-term concern (10-20% at 10 years)

Salvage Options for Failed 4CF:

  • Total wrist arthrodesis (most common)
  • Revision four-corner fusion (selected cases)
  • Total wrist arthroplasty (low demand, rare)

These comprehensive outcome data demonstrate the risk-benefit profile essential for informed consent and exam discussions.

Proximal Row Carpectomy

Alternative motion-preserving procedure removing the proximal carpal row and creating radial capitate articulation. Simpler procedure than four-corner fusion but requires intact lunate fossa cartilage.

PRC Contraindications: Lunate fossa chondromalacia, capitate cartilage degeneration, inflammatory arthritis, and high-demand patients are contraindications. Intraoperative assessment of cartilage quality is essential - if lunate fossa shows Grade III-IV changes, convert to four-corner fusion or total wrist arthrodesis. Do not proceed with PRC if cartilage inadequate.

Proximal Row Carpectomy Indications:

Ideal Candidate:

  • SLAC or SNAC Stage II
  • Intact lunate fossa articular cartilage
  • Intact capitate articular cartilage
  • Low to moderate functional demands
  • Age typically greater than 50 years
  • Desire for motion preservation
  • Failed conservative treatment

Advantages Over Four-Corner Fusion:

  • Single-stage procedure (no waiting for fusion)
  • No implants (no hardware complications)
  • No nonunion risk
  • Simpler technique
  • Shorter operative time
  • Lower cost

Disadvantages Compared to 4CF:

  • Requires excellent cartilage (strict criteria)
  • Lower grip strength (70-75% vs 75-80%)
  • Progressive arthritis risk higher
  • Less predictable long-term outcomes
  • Not suitable for inflammatory arthritis

Absolute Contraindications:

  • Lunate fossa chondromalacia (Grade III-IV)
  • Capitate head cartilage degeneration
  • Inflammatory arthritis (RA, psoriatic)
  • Prior Kienbock disease
  • Avascular necrosis capitate
  • SLAC Stage IV

Relative Contraindications:

  • High-demand manual laborer
  • Young patient (less than 30 years)
  • Tobacco use
  • Workers compensation (controversial)

Preoperative Assessment:

  • CT scan to evaluate lunate fossa
  • Consider wrist arthroscopy to confirm cartilage quality
  • Intraoperative decision-making paramount
  • Have backup plan (4CF or total wrist fusion)

The procedure works best in older, lower-demand patients with well-preserved cartilage discovered intraoperatively.

Proximal Row Carpectomy Technique:

Preoperative Planning:

  • Review CT imaging for lunate fossa assessment
  • Counsel patient on potential conversion to 4CF
  • Consent for possible alternative procedure
  • Mark incision

Approach:

  • Dorsal longitudinal incision (similar to 4CF)
  • Identify dorsal sensory nerve branches
  • Elevate extensor retinaculum
  • Capsulotomy exposing midcarpal joint

Cartilage Assessment:

  • Inspect lunate fossa cartilage BEFORE bone removal
  • Grading: Outerbridge I-II acceptable, III-IV contraindication
  • Assess capitate head cartilage
  • If inadequate: Convert to four-corner fusion
  • Document findings

Bone Removal:

  • Identify scaphoid, lunate, triquetrum
  • Excise scaphoid first (piecemeal with rongeur)
  • Remove lunate carefully (preserve cartilage)
  • Excise triquetrum
  • Remove all proximal row completely
  • Inspect for loose fragments

Shaping and Contouring:

  • Smooth any sharp edges on radius
  • Consider minimal radial styloidectomy (controversial)
  • Shape capitate to match lunate fossa
  • Achieve congruent articulation
  • Test ROM intraoperatively

Stability Assessment:

  • Fluoroscopic assessment in multiple planes
  • Ensure no impingement
  • Confirm capitate remains reduced
  • Assess radioscaphoid space

Closure:

  • Capsular repair if possible
  • Retinaculum reconstruction
  • Skin closure
  • Short-arm splint

Key Technical Points:

  • DO NOT proceed if cartilage inadequate
  • Complete bone removal prevents impingement
  • Minimal bone shaping (preserve anatomy)
  • Early motion protocol (vs 4CF)

Intraoperative Decision Algorithm:

  • Excellent cartilage: Proceed with PRC
  • Marginal cartilage: Consider 4CF
  • Poor cartilage: Convert to 4CF or total wrist fusion
  • Young high-demand patient: Consider 4CF even with good cartilage

This detailed technique emphasizes the critical intraoperative decision-making that separates this procedure from four-corner fusion.

PRC Postoperative Protocol:

Immediate (0-2 Weeks):

  • Short-arm splint for comfort
  • Elevation and icing
  • Finger ROM immediately
  • Shoulder and elbow motion
  • Wound care

Early (2-6 Weeks):

  • Remove sutures at 2 weeks
  • Transition to removable splint
  • Begin gentle wrist AROM at 2-3 weeks (earlier than 4CF)
  • Hand therapy referral
  • Progressive ROM exercises

Intermediate (6-12 Weeks):

  • Full AROM encouraged
  • Begin strengthening exercises
  • Functional activities progressive loading
  • Return to light duty work 6-8 weeks
  • Monitor for pain/swelling

Late (3-6 Months):

  • Unrestricted activities as tolerated
  • Progressive resistance strengthening
  • Return to manual labor 3-4 months
  • Final outcome assessment 6-12 months

Expected Recovery:

  • Faster than 4CF (no fusion to protect)
  • ROM plateau by 3-4 months
  • Strength improvement to 12 months
  • Sedentary work: 4-6 weeks
  • Manual labor: 3-4 months

Long-term Monitoring:

  • Annual radiographs years 1-3
  • Assess for progressive arthritis
  • Monitor capitolunate interval
  • Document functional outcomes

Comparison to Four-Corner Fusion:

  • Earlier ROM exercises (2-3 weeks vs 8-12 weeks)
  • Faster return to work
  • No fusion protection period
  • Earlier strengthening initiation
  • Lower overall morbidity

The accelerated rehabilitation represents a significant advantage over four-corner fusion in appropriate candidates.

Proximal Row Carpectomy Results:

Motion Outcomes:

  • Flexion-extension arc: 50-60% contralateral
  • Similar motion to four-corner fusion
  • Radial-ulnar deviation: 40-50%
  • Forearm rotation: Preserved

Strength Outcomes:

  • Grip strength: 70-75% contralateral (slightly lower than 4CF)
  • Pinch strength: 80-85%
  • Progressive improvement to 12 months

Pain and Function:

  • Pain relief: 80-85% good/excellent
  • DASH improvement: 25-35 points
  • Return to work: 85-90%
  • Satisfaction: 75-85%

Comparative Studies (PRC vs 4CF):

  • Similar motion preservation (no significant difference)
  • Grip strength favors 4CF (5-10% stronger)
  • Faster recovery with PRC
  • Lower complication rate PRC (no nonunion risk)
  • Similar long-term satisfaction

Long-term Results:

  • 10-year survival: 70-80%
  • Progressive arthritis: 20-30% at 10 years
  • Conversion to wrist fusion: 10-15%
  • Radiocapitate arthritis most common failure

Predictors of Success:

  • Excellent preoperative cartilage
  • Low-demand patient
  • Older age (greater than 50 years)
  • Non-inflammatory arthritis
  • Non-smoker

Predictors of Failure:

  • Poor cartilage at surgery
  • Young high-demand patient
  • Inflammatory arthritis
  • Progression to radiocapitate arthritis

Complications:

  • Progressive arthritis: 20-30% long-term
  • Clunking/clicking: 10-15%
  • Persistent pain: 10-15%
  • Capitate subsidence: Rare
  • Ulnar impaction: 5-10%

Salvage for Failed PRC:

  • Total wrist arthrodesis (definitive)
  • Radiocapitate fusion (limited role)
  • Total wrist arthroplasty (low demand, rare)

These outcome data guide appropriate patient selection and expectation management comparing PRC to four-corner fusion alternatives.

Total Wrist Arthrodesis

Definitive salvage procedure providing reliable pain relief and maximum grip strength at cost of complete wrist motion loss. Indicated for Stage IV SLAC, inflammatory arthritis, and salvage situations.

Total Wrist Arthrodesis Indications:

Primary Indications:

  • SLAC/SNAC Stage IV (pancarpal arthritis)
  • Failed four-corner fusion
  • Failed proximal row carpectomy
  • Severe inflammatory arthritis
  • Post-traumatic pancarpal arthritis
  • High-demand patient requiring maximum strength
  • Salvage for infection/osteonecrosis

Patient Factors Favoring Total Fusion:

  • High-demand manual laborer
  • Bilateral disease (can fuse dominant, preserve motion contralateral)
  • Desire for maximum pain relief and strength
  • Understanding of functional limitations
  • Failed motion-preserving procedures

Advantages:

  • Definitive pain relief (90-95%)
  • Maximum grip strength (85-90% normal)
  • Predictable union (95% with modern fixation)
  • Single definitive procedure
  • Allows heavy labor/impact activities

Disadvantages:

  • Complete loss of wrist motion
  • Impact on ADLs (hygiene, typing, driving)
  • Adjacent joint stress (CMC, elbow)
  • Irreversible procedure
  • Psychosocial impact

Position Planning:

  • Dominant hand: 10-15° extension, neutral deviation
  • Non-dominant: 0-10° extension, 5-10° ulnar deviation
  • Bilateral: Different positions optimize function
  • Consider patient occupation and activities

This procedure represents the gold standard for definitive treatment when motion preservation is not possible or has failed.

Total Wrist Arthrodesis Technique:

Preoperative Planning:

  • Confirm fusion position with patient (mock positioning)
  • Select implant (plate vs rod vs hybrid)
  • Template radiographs
  • Assess bone quality
  • Plan bone grafting if needed

Positioning and Approach:

  • Dorsal longitudinal incision
  • Identify extensor retinaculum
  • Elevate retinaculum as flap
  • Expose radiocarpal and midcarpal joints
  • Preserve EPL tendon

Joint Preparation:

  • Denude all articular cartilage:
    • Radiocarpal articulation
    • Midcarpal joints
    • CMC joints (second and third rays)
  • Fish-scale technique with curets and burrs
  • Remove to bleeding subchondral bone
  • Preserve bone stock (avoid excessive removal)

Position and Reduction:

  • Extension: 10-15° (dominant), 0-10° (non-dominant)
  • Radial/ulnar deviation: Neutral to 5-10° ulnar
  • Pronation/supination: Neutral
  • Third metacarpal aligned with radius
  • K-wire temporary fixation
  • Fluoroscopic confirmation lateral and PA views

Fixation Options:

Dorsal Plate (Most Common):

  • Pre-contoured wrist fusion plate
  • Distal screws into third metacarpal
  • Proximal screws into radius
  • Locking screw technology
  • Rigid construct allows early mobilization

Intramedullary Rod:

  • Rush rod or similar
  • Less soft tissue dissection
  • Lower profile
  • Technically demanding
  • Require supplemental K-wires or screws

Combined Technique:

  • Plate plus supplemental screws
  • Maximum rigidity
  • Complex reconstruction
  • Revision cases

Bone Grafting:

  • Autograft from distal radius (local)
  • Iliac crest for large defects
  • Allograft supplementation
  • Pack around fusion site
  • Consider BMP for high-risk (smokers, revision)

Closure:

  • Meticulous hemostasis
  • Retinaculum repair over plate
  • Skin closure without tension
  • Well-padded short-arm splint

Technical Pearls:

  • Position is critical - cannot revise easily
  • Thorough cartilage removal essential
  • Rigid fixation improves union rates
  • Bone graft enhances fusion in high-risk patients
  • Preserve soft tissue envelope

This comprehensive technique demonstrates mastery required for this definitive but irreversible procedure.

Total Wrist Arthrodesis Results:

Union Rates:

  • Modern plate fixation: 95-98%
  • Intramedullary rod: 90-95%
  • Radiographic union: 12-16 weeks
  • Factors reducing union: Smoking, diabetes, RA

Functional Outcomes:

  • Grip strength: 85-90% contralateral
  • Pinch strength: 90-95% contralateral
  • Pain relief: 90-95% good/excellent
  • Return to work: 95%
  • Satisfaction: 80-90%

Motion Impact:

  • Wrist flexion-extension: 0°
  • Radial-ulnar deviation: 0°
  • Forearm rotation: Preserved
  • Compensatory motion: Elbow, shoulder, finger

Functional Limitations:

  • Toileting/hygiene: Challenging initially
  • Keyboard use: Adaptation required
  • Writing: Altered technique
  • Driving: Usually manageable
  • Sports: Contact/impact activities tolerated

Complications:

  • Nonunion: 2-5% with modern fixation
  • Malunion: 5% (incorrect position)
  • Hardware prominence/irritation: 10-15%
  • Infection: 2-3%
  • CRPS: 3-5%
  • Adjacent joint arthritis: 10-15% long-term (CMC, DRUJ)

Salvage for Complications:

  • Nonunion: Revision fusion with bone graft ± BMP
  • Malunion: Corrective osteotomy (technically demanding)
  • Hardware problems: Removal after solid fusion
  • Infection: Debridement, antibiotics, external fixator

Long-term Outcomes:

  • 20-year studies show durable pain relief
  • Adjacent joint arthritis develops but often asymptomatic
  • Patient adaptation improves over first year
  • Bilateral fusion extremely limiting

Quality of Life:

  • DASH scores improve 30-40 points
  • Most patients satisfied despite motion loss
  • Appropriate patient selection critical
  • Younger patients adapt better

These extensive outcome data demonstrate why total wrist fusion remains gold standard for salvage despite complete motion loss.

Total Wrist Arthroplasty

Motion-preserving alternative for pancarpal arthritis in selected low-demand patients. Limited role given high complication rates but valuable for bilateral disease or specific situations.

Indications:

  • Bilateral wrist arthritis (preserve motion one side if fusion contralateral)
  • Low-demand elderly patient
  • Inflammatory arthritis with good bone stock
  • Patient unable to tolerate wrist fusion limitations

Contraindications:

  • High-demand activities
  • Poor bone quality
  • Active infection
  • Inadequate soft tissue envelope
  • Young patient
  • Manual labor

Implant Designs:

  • Universal 2 (commonly used)
  • Maestro (modular)
  • ReMotion (third generation)
  • Evolving technology

Expected Outcomes:

  • Motion: 60-80° flexion-extension arc
  • Grip: 60-70% normal
  • Revision rate: 15-25% at 10 years
  • Complications: Loosening, subsidence, dislocation, infection

Role in Midcarpal Arthritis:

  • Very limited application
  • Reserve for exceptional cases
  • Total wrist fusion more reliable
  • Consider bilateral wrist disease

Evidence Base and Outcomes Studies

PRC vs Four-Corner Arthrodesis for SLAC Wrist

Vanhove W, et al. • J Hand Surg Eur Vol (2008)
Key Findings:
  • Prospective comparative study of 38 patients (18 PRC, 20 4CF)
  • Similar motion: PRC 54 degrees, 4CF 58 degrees arc
  • Grip strength favored 4CF: 75% vs 70% contralateral
  • Pain relief equivalent between procedures
  • Complication rate lower with PRC due to no nonunion risk
Clinical Implication: Clinical equipoise between PRC and 4CF for motion and pain outcomes. The 5% grip strength advantage with 4CF must be weighed against PRC requirement for pristine cartilage.

Motion-Preserving Procedures for SLAC Wrist

Wyrick JD, et al. • J Hand Surg Am (1995)
Key Findings:
  • Prospective randomized trial of 25 patients
  • No difference in motion: PRC 60 degrees, 4CF 62 degrees
  • No difference in pain scores or satisfaction at 2-year follow-up
  • 4CF had 8% nonunion rate
  • PRC showed faster recovery
Clinical Implication: Level I evidence demonstrates functional equivalence between procedures in appropriately selected patients. PRC faster recovery and absence of nonunion risk make it attractive when cartilage quality permits.

Four-Corner Fusion with Headless Compression Screws

Bedford B, et al. • J Hand Surg Eur Vol (2010)
Key Findings:
  • Retrospective review of 67 four-corner fusions
  • 90% union rate at mean 14 weeks
  • Grip strength 78% contralateral
  • Flexion-extension arc 75 degrees
  • Hardware removal required in 6% for prominence
  • Patient satisfaction 88%
Clinical Implication: Headless screw fixation is reliable for 4CF with high union rates. The 6% hardware removal rate is lower than dorsal plates, suggesting advantage of buried fixation.

PRC vs 4CF Biomechanical and Clinical Review

Cohen MS, Kozin SH • J Hand Surg Am (2001)
Key Findings:
  • Review of biomechanical and clinical studies comparing PRC and 4CF
  • PRC contact forces 50% higher than 4CF on lunate fossa
  • Higher contact forces explain higher progression to arthritis with PRC
  • 4CF more predictable long-term outcomes
  • 4CF has higher short-term complication rate
Clinical Implication: PRC shows higher late failure from progressive radiocapitate arthritis. Increased contact forces provide rationale for preferring 4CF in younger high-demand patients.

Long-term Four-Corner Fusion Outcomes

Kirschenbaum D, et al. • J Hand Surg Am (1993)
Key Findings:
  • Long-term follow-up (mean 9 years) of 20 four-corner fusions
  • 85% good/excellent results
  • Motion averaged 73 degrees flexion-extension arc (62% contralateral)
  • Progressive arthritis developed in 15% but remained asymptomatic
  • No nonunions with wire fixation technique
Clinical Implication: Early long-term study established 4CF durability. The 15% radiographic progression without symptoms demonstrates radiographic changes do not always correlate with clinical failure.

Exam Viva Scenarios

Practice these scenarios to excel in your viva examination

VIVA SCENARIOModerate

EXAMINER

"A 55-year-old carpenter presents with chronic dorsal wrist pain following a scaphoid fracture 10 years ago. Radiographs show scaphoid nonunion with arthritis between the proximal scaphoid fragment and radius, as well as between the capitate and lunate. The radiolunate joint appears well preserved. How would you classify and manage this?"

EXCEPTIONAL ANSWER
This patient has SNAC wrist, which follows the same pattern as SLAC but results from scaphoid nonunion rather than ligament injury. Based on the description, this is Stage III SNAC with radioscaphoid and midcarpal (capitolunate) arthritis but preserved radiolunate articulation. Initial management includes conservative measures - NSAIDs, activity modification, splinting, and corticosteroid injection. If conservative treatment fails after 6 months, surgical options include four-corner fusion or proximal row carpectomy. Given his occupation as a carpenter requiring grip strength, I would favor four-corner fusion. This involves scaphoid excision and arthrodesis of the capitate, hamate, lunate, and triquetrum with preservation of the radiolunate joint. Expected outcomes are 75-80% grip strength and 50-60% motion with 85-90% pain relief.
KEY POINTS TO SCORE
SNAC wrist mirrors SLAC progression but initiates from scaphoid nonunion
Stage III indicates midcarpal arthritis with preserved radiolunate joint
Four-corner fusion indicated for Stage II-III SLAC/SNAC
4CF preserves radiolunate articulation (explains why scaphoid excision works)
Carpenter (high demand) benefits from 4CF grip strength advantage over PRC
Expected outcomes: 75-80% grip, 50-60% motion, 85-90% pain relief
COMMON TRAPS
✗Don't attempt scaphoid fixation with established arthritis - nonunion is chronic
✗Don't recommend PRC without assessing cartilage quality intraoperatively
✗Don't suggest total wrist fusion for Stage III (preserve motion when possible)
✗Don't miss that radiolunate preservation is why motion-sparing surgery works
✗Don't operate without adequate conservative trial (minimum 6 months)
LIKELY FOLLOW-UPS
"What is the difference between SLAC and SNAC? (SLAC from SL ligament injury, SNAC from scaphoid fracture nonunion, same staging)"
"Why does the radiolunate joint remain preserved? (Lunate protected in neutral position, scaphoid proximal fragment rotates causing malalignment)"
"What fixation would you use for four-corner fusion? (Headless screws vs circular plate, both effective)"
"What are contraindications to PRC? (Lunate fossa chondromalacia, inflammatory arthritis, capitate cartilage loss)"
"What if radiolunate joint also shows arthritis? (Stage IV - requires total wrist arthrodesis)"
VIVA SCENARIOModerate

EXAMINER

"You perform a dorsal approach for four-corner fusion in a 62-year-old woman with Stage III SLAC wrist. After excising the scaphoid and exposing the midcarpal joint, you inspect the lunate fossa cartilage and find it pristine with no evidence of degeneration. The capitate head also shows excellent cartilage. Your surgical plan was four-corner fusion but the findings suggest PRC might be possible. How do you proceed?"

EXCEPTIONAL ANSWER
This scenario represents an intraoperative decision point where excellent cartilage quality suggests PRC feasibility. I would systematically consider several factors: First, patient age (62) and occupation/demands favor PRC. Second, the pristine lunate fossa and capitate cartilage meet PRC requirements. However, I must also consider: Was this discussed in preoperative consent? Does the patient understand recovery differences? What are her functional demands and expectations? If high-demand activities or desire for maximum grip strength were discussed, I would proceed with planned four-corner fusion despite good cartilage. If low-moderate demand patient and PRC was mentioned as possibility pending intraoperative findings, I could proceed with PRC after confirming Grade I-II cartilage quality. The decision should be made preoperatively with patient understanding that final choice depends on cartilage quality. In this case, given age 62 and excellent cartilage, PRC would be reasonable if appropriately consented, offering faster recovery and avoiding nonunion risk.
KEY POINTS TO SCORE
Intraoperative cartilage assessment is gold standard for PRC decision
Outerbridge Grade I-II cartilage required for PRC, Grade III-IV contraindication
Patient factors: age greater than 60 and low-moderate demand favor PRC
Preoperative consent must include possibility of procedure change based on findings
PRC advantages: faster recovery, no nonunion risk, simpler procedure
4CF advantages: 5-10% better grip strength, more predictable long-term
COMMON TRAPS
✗Don't change procedure without preoperative consent discussion
✗Don't assume cartilage appearance on CT predicts intraoperative quality
✗Don't perform PRC in high-demand patient even with good cartilage
✗Don't proceed with PRC if any inflammatory arthritis present
✗Don't forget to document decision-making rationale in operative note
LIKELY FOLLOW-UPS
"How would you grade the cartilage? (Outerbridge classification I-IV, I-II acceptable for PRC)"
"What are advantages of PRC over 4CF? (Faster recovery, no fusion complications, simpler surgery, lower cost)"
"What are advantages of 4CF over PRC? (5-10% better grip, more predictable long-term, lower progression risk)"
"If you found Grade III lunate fossa changes? (Contraindication to PRC, proceed with 4CF or total wrist fusion)"
"How would postoperative rehabilitation differ? (PRC mobilizes at 2-3 weeks vs 4CF at 8-12 weeks after fusion)"

MCQ Practice Points

Exam Pearl

Q: What is the typical progression pattern of SLAC (Scapholunate Advanced Collapse) wrist?

A: SLAC progression: Stage I - radial styloid to scaphoid. Stage II - entire radioscaphoid joint. Stage III - capitolunate joint. The radiolunate joint is spared due to preserved spherical congruency. This pattern guides surgical decision-making: PRC possible if capitate head intact.

Exam Pearl

Q: What distinguishes SNAC from SLAC wrist arthritis?

A: SNAC (Scaphoid Nonunion Advanced Collapse) results from scaphoid nonunion. SLAC results from scapholunate ligament injury. Both progress similarly through radioscaphoid then capitolunate joints. Key difference: SNAC shows scaphoid nonunion with humpback deformity and DISI pattern. Both spare radiolunate joint.

Exam Pearl

Q: What are the surgical options for midcarpal arthritis with intact radiolunate joint?

A: Options include: Proximal row carpectomy (PRC) - requires intact capitate head and radiolunate joint; Four-corner fusion (scaphoid excision + capitate-lunate-hamate-triquetrum fusion) - preserves more motion than total wrist fusion. PRC simpler with faster recovery; four-corner preserves more grip strength.

Exam Pearl

Q: What radiographic measurement indicates scapholunate dissociation leading to SLAC wrist?

A: Scapholunate angle greater than 70° (normal 30-60°) indicates dissociation. Terry Thomas sign - scapholunate gap greater than 3mm (or greater than 2mm difference from contralateral). Scaphoid ring sign on PA view indicates flexed scaphoid. DISI pattern (dorsal intercalated segment instability) shows lunate extended dorsally.

Exam Pearl

Q: Why is the radiolunate joint preserved in SLAC and SNAC wrist arthritis?

A: The radiolunate joint maintains spherical congruency even with carpal malalignment, distributing load evenly. The radioscaphoid joint has elliptical articulation, making it susceptible to point-loading with scaphoid malposition. This preservation makes PRC and four-corner fusion viable options.

Australian Context

Epidemiology

Wrist Arthritis Patterns in Australia:

  • Midcarpal arthritis secondary to SLAC/SNAC represents significant portion of secondary wrist OA
  • Agricultural and manual labor industries (farming, mining, construction) show higher SLAC rates
  • Work-related scaphoid fractures common in young men aged 15-35 years
  • Delayed presentation of scaphoid nonunion contributes to SNAC burden
  • Indigenous communities may have higher rates due to occupational factors and healthcare access

Healthcare System Integration

Referral Pathways:

  • GP initial assessment with plain radiographs (PA, lateral, clenched fist view)
  • Referral to hand surgery (subspecialty orthopaedics or plastic surgery)
  • Public hospital hand surgery waiting lists vary 6-18 months
  • Private sector offers faster access for insured patients
  • Workers' compensation cases require icare/WorkCover approval in NSW

Australian Clinical Guidelines

Evidence-Based Practice:

  • No specific Australian guidelines for midcarpal arthritis
  • RACS and Australian Hand Surgery Society recommendations guide practice
  • Conservative management prioritized with minimum 6-month trial
  • Shared decision-making for surgical procedure selection (PRC vs 4CF)
  • Occupational factors heavily influence surgical planning

Conservative Management Access:

  • Hand therapy through public outpatient departments
  • Private hand therapists (rebates via private health insurance extras)
  • Medicare rebates for GP-prescribed splints through MASS program (limited)
  • Exercise physiologist services may assist with work conditioning

PBS Listings

Pharmacological Management:

DrugPBS StatusAuthority
NaproxenGeneral PBSNo authority
CelecoxibStreamlinedOA indication
EtoricoxibStreamlinedOA indication
TramadolAuthorityChronic pain
Paracetamol SRGeneral PBSNo authority

Rehabilitation Framework

Hand Therapy Standards:

  • Australian Hand Therapy Association (AHTA) certified therapists
  • Post-PRC: early mobilization protocol (2-3 weeks)
  • Post-4CF: immobilization 8-12 weeks until fusion confirmed
  • Post-fusion: splint weaning and strengthening program
  • Occupational rehabilitation for return-to-work planning

Occupational Considerations

WorkCover/icare Integration:

  • Scaphoid nonunion often linked to workplace injury
  • Workers' compensation may cover surgery, rehabilitation, and wage replacement
  • Case managers coordinate return-to-work programs
  • Permanent impairment assessment using AMA Guides (4th or 5th edition)
  • Job modification or retraining if unable to return to heavy manual work

Capacity Assessment:

  • Functional capacity evaluation (FCE) for return-to-work clearance
  • Grip strength benchmarks for occupation-specific demands
  • Typical return to sedentary work: 8-12 weeks post-PRC, 12-16 weeks post-4CF
  • Return to heavy manual work: 16-24 weeks with restrictions

High-Yield Exam Summary

SLAC Staging - RAMS

  • •R: Radial styloid arthritis (Stage I) - radial styloidectomy
  • •A: Articulation scaphoid fossa (Stage II) - 4CF or PRC
  • •M: Midcarpal capitolunate arthritis (Stage III) - 4CF or PRC
  • •S: Stage IV adds pancarpal + DRUJ - total wrist fusion
  • •Radiolunate preserved until Stage IV (key concept)
  • •SNAC follows identical staging from scaphoid nonunion

Four-Corner Fusion Essentials

  • •Scaphoid excision + fuse capitate-hamate-lunate-triquetrum
  • •Preserves radiolunate joint (motion source)
  • •Outcomes: 75-80% grip, 50-60% motion, 85-90% pain relief
  • •Union rate 90-95% with rigid fixation
  • •Immobilize 8-12 weeks until fusion
  • •Complications: nonunion 5-10%, hardware prominence 10-20%

PRC vs 4CF Decision

  • •PRC requires pristine lunate fossa cartilage (Grade I-II)
  • •PRC: faster recovery, no nonunion, 70-75% grip
  • •4CF: better grip (75-80%), more predictable long-term
  • •PRC contraindications: inflammatory arthritis, poor cartilage, high demand
  • •Intraoperative cartilage assessment definitive
  • •Both achieve similar 50-60% motion preservation

Total Wrist Arthrodesis

  • •Indications: Stage IV SLAC, failed 4CF/PRC, high demand
  • •Position: 10-15° extension, neutral to 5-10° ulnar deviation
  • •Outcomes: 85-90% grip (best), 90-95% pain relief, 95% union
  • •Complete motion loss impacts ADLs significantly
  • •Plate fixation most common, allows early mobilization
  • •Consider bilateral disease (fuse one, preserve other)

PRC Contraindications

  • •Lunate fossa chondromalacia (Grade III-IV)
  • •Capitate articular cartilage degeneration
  • •Inflammatory arthritis (RA, psoriatic)
  • •Kienbock disease (AVN lunate)
  • •High-demand manual laborer
  • •Young patient (relative, consider 4CF instead)

Physical Examination

  • •Watson test: scaphoid shift with SL instability
  • •Midcarpal shift test: clunk ulnar to radial deviation
  • •Point tenderness scapholunate interval (dorsal)
  • •Grip strength typically 40-60% reduced
  • •ROM measurement and comparison to contralateral
  • •DRUJ assessment (Stage IV consideration)

Imaging Assessment

  • •PA wrist: SL gap (greater than 3mm), scaphoid ring sign
  • •Lateral: SL angle (normal 30-60°, DISI greater than 70°)
  • •Clenched fist: Dynamic SL instability
  • •CT scan: Assess arthritis extent, plan fixation, evaluate lunate fossa
  • •MRI: Limited role in arthritis (ligament assessment early)
  • •Arthroscopy: Gold standard cartilage evaluation

Surgical Pearls

  • •4CF: Complete scaphoid excision prevents impingement
  • •4CF: Thorough cartilage removal to bleeding bone essential
  • •PRC: Don't proceed if cartilage inadequate (convert to 4CF)
  • •Total fusion: Position critical (cannot easily revise)
  • •All: Preserve soft tissue envelope and blood supply
  • •All: Rigid fixation improves union rates

Summary

Midcarpal arthritis represents a complex spectrum of degenerative wrist conditions requiring thorough understanding of carpal biomechanics, staging systems, and surgical options. SLAC and SNAC wrist patterns progress through predictable stages, with radiolunate joint preservation until late disease enabling motion-preserving surgery.

Four-corner fusion and proximal row carpectomy both achieve approximately 50-60% motion preservation with good pain relief in appropriately selected patients. Four-corner fusion provides superior grip strength and more predictable long-term outcomes but requires fusion healing and carries nonunion risk. Proximal row carpectomy offers simpler surgery with faster recovery but demands pristine lunate fossa cartilage and shows higher late progression rates.

Total wrist arthrodesis remains the gold standard for definitive treatment when motion preservation fails or is not feasible, providing maximum grip strength and reliable pain relief despite complete motion loss. Patient selection, understanding individual functional demands, and mastery of multiple surgical techniques are essential for optimal outcomes in this challenging condition.

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