TOTAL ELBOW ARTHROPLASTY - JOINT RECONSTRUCTION
Linked vs Unlinked Design | Rheumatoid Arthritis Classic Indication | Ulnar Nerve Protection Critical | Triceps Management Essential
TEA IMPLANT DESIGN CLASSIFICATION
Critical Must-Knows
- Classic indication: Rheumatoid arthritis with severe joint destruction and minimal bone loss
- Ulnar nerve management: Must be identified, protected, and often transposed anteriorly
- Triceps-sparing approach: Preserves extensor mechanism, allows early rehabilitation
- Weight restriction: Lifetime limit of 2-5kg lifting to reduce bushing wear and loosening
- Linked implants: Sloppy hinge design allows 7-10 degrees varus-valgus laxity to reduce stress
Examiner's Pearls
- "Linked TEA is preferred for bone loss, instability, or revision - relies on hinge for stability
- "Ulnar nerve palsy is the most common neurological complication - always identify and protect
- "Triceps insufficiency causes significant functional deficit - extensor mechanism is critical
- "Aseptic loosening at ulna is more common than humerus due to smaller bone stock
Clinical Imaging
Imaging Gallery
Critical Total Elbow Arthroplasty Exam Points
Linked vs Unlinked Design
Linked (semi-constrained) implants have a sloppy hinge mechanism allowing 7-10 degrees varus-valgus laxity. Used when soft tissues are incompetent or bone loss is significant. Unlinked implants rely on intact ligaments and soft tissues for stability. Similar concepts to constrained vs unconstrained knee arthroplasty.
Ulnar Nerve Management
The ulnar nerve must be identified, protected, and often transposed anteriorly during TEA. It runs posterior to the medial epicondyle and is at risk during surgical approach. Ulnar nerve palsy is the most common neurological complication (5-10%). Pre-existing neuropathy is common in RA patients.
Triceps Mechanism
The triceps extensor mechanism is critical for elbow function. Approaches include triceps-on (Kocher), triceps-sparing (Bryan-Morrey), and triceps-reflecting (paratricipital). Triceps insufficiency causes significant functional limitation. Triceps-sparing approach allows earlier rehabilitation.
Weight Restriction Critical
Patients must adhere to lifelong weight restrictions (2-5kg) to minimize stress on the prosthesis. This prevents accelerated bushing wear and loosening. TEA is a semi-permanent solution - patients must understand activity limitations. Non-compliance leads to early failure.
Quick Decision Guide - TEA Implant Selection
| Patient Profile | Bone/Soft Tissue Status | Implant Choice | Key Pearl |
|---|---|---|---|
| Rheumatoid arthritis, low demand | Intact bone stock, competent ligaments | Unlinked (resurfacing) TEA | Preserves bone, relies on soft tissues |
| RA with bone loss, instability | Deficient bone, incompetent collaterals | Linked (semi-constrained) TEA | Hinge provides stability when soft tissues fail |
| Distal humerus fracture in elderly | Comminuted, osteoporotic bone | TEA (linked) or hemiarthroplasty | Better outcomes than ORIF in elderly with comminution |
| Failed prior TEA, bone loss | Significant bone deficiency | Revision TEA with long stems and allograft | Complex revision with bone grafting |
TEARSTEARS - TEA Complications
Memory Hook:Total Elbow Arthroplasty Results in TEARS if complications occur - Triceps, Erosion, Aseptic loosening, Rupture, Sepsis
LINCLINC - Linked TEA Indications
Memory Hook:Use LINKed TEA when there is LINC - Ligament incompetence, Instability, No bone, Complex revision
PRIMEPRIME - Pre-Op Assessment
Memory Hook:Before TEA, patients must be in PRIME condition - Prior surgery, Range, Infection, Muscle, Electrical nerve
Overview and Epidemiology
Total elbow arthroplasty (TEA) replaces the ulnohumeral and radiocapitellar articulations to restore a pain-free, functional arc of motion. It is performed less frequently than hip or knee arthroplasty due to the elbow's complex biomechanics and higher complication rates.
Epidemiology:
- Rheumatoid arthritis historically the most common indication (60-70%)
- Post-traumatic arthritis and acute distal humerus fractures increasing
- More common in females due to higher RA prevalence
- Complex anatomy and biomechanics make surgery technically demanding
Elbow Function Requirements
Functional arc of motion for activities of daily living is 30-130 degrees flexion and 50 degrees each of pronation and supination. TEA aims to restore this arc while providing stability and pain relief. Most patients achieve a functional arc post-operatively.
Etiology - Indications for TEA:
Primary Indications
- Rheumatoid arthritis: Classic indication with severe joint destruction
- Primary osteoarthritis: Less common, typically with stiffness
- Post-traumatic arthritis: Following distal humerus fracture malunion
- Hemophilic arthropathy: Severe recurrent hemarthrosis
Acute Trauma Indications
- Distal humerus fracture in elderly: Comminuted, osteoporotic bone
- Failed ORIF: Non-union or malunion with arthritis
- Unreconstructable fracture: When ORIF not possible
- Age greater than 65 with low demand and comminution: Better outcomes than ORIF
Contraindications:
- Absolute: Active infection, inadequate soft tissue coverage, non-functional upper limb (e.g., stroke)
- Relative: Young age (under 60), high activity level, prior septic arthritis, severe bone loss without reconstruction options
Anatomy and Biomechanics
The Elbow Joint Complex:
The elbow is a trochoginglymoid joint consisting of three articulations:
Elbow Joint Articulations
| Articulation | Bones | Motion | Stability Contribution |
|---|---|---|---|
| Ulnohumeral | Trochlea - trochlear notch | Flexion-extension (hinge) | Primary stability in extension |
| Radiocapitellar | Capitellum - radial head | Pronation-supination (pivot) | Secondary stabilizer, axial load (40%) |
| Proximal radioulnar | Radial head - radial notch of ulna | Forearm rotation | Minimal contribution to elbow stability |
Stability - Primary and Secondary Stabilizers:
Elbow Stability Hierarchy
Primary stabilizers: Ulnohumeral articulation (coronoid is critical), medial collateral ligament (MCL - anterior bundle), lateral collateral ligament complex (LUCL). Secondary stabilizers: Radial head, capsule, common flexor and extensor origins. Loss of primary stabilizers leads to instability that may require linked TEA.
Medial Collateral Ligament:
- Anterior bundle: Most important, origin at medial epicondyle, inserts on sublime tubercle of coronoid
- Posterior bundle: Tightens in flexion
- Transverse ligament: Minimal contribution
Lateral Collateral Ligament Complex:
- Radial collateral ligament
- Lateral ulnar collateral ligament (LUCL): Most important, prevents posterolateral rotatory instability
- Annular ligament: Stabilizes proximal radioulnar joint
Ulnar Nerve Anatomy:
Ulnar Nerve at Elbow
The ulnar nerve passes posterior to the medial epicondyle in the cubital tunnel. It lies between the medial epicondyle and olecranon, covered by Osborne's ligament (arcuate ligament). The nerve is at risk during medial approach and must be identified early. Pre-existing ulnar neuropathy is common in RA patients (15-25%).
Triceps Mechanism:
- Three heads: Long head (scapula), lateral head (humerus), medial head (deep, humerus)
- Inserts on olecranon via common triceps tendon
- Critical for elbow extension and function
- Preservation or secure repair essential for TEA success
Classification Systems
TEA Implant Design Classification
Based on constraint and stability mechanism:
| Design Type | Mechanism | Indications | Key Features |
|---|---|---|---|
| Linked (semi-constrained) | Sloppy hinge with 7-10 degrees varus-valgus | Bone loss, instability, RA, revision | Coonrad-Morrey, Discovery Elbow |
| Unlinked (resurfacing) | Ball and socket, relies on soft tissues | Primary OA, intact ligaments | Kudo, Capitellocondylar |
| Convertible | Can switch between linked and unlinked | Intraoperative flexibility | Latitude, Nexel |
| Hemiarthroplasty | Distal humerus replacement only | Acute fracture in elderly | Stryker Discovery Hemi |
Sloppy Hinge Concept
Linked (semi-constrained) TEA uses a sloppy hinge mechanism with 7-10 degrees of varus-valgus laxity. This is NOT a fully constrained hinge - the laxity allows stress transfer to soft tissues rather than concentrating all forces at the bone-cement interface, reducing loosening risk.
Clinical Assessment
History:
Pain Characteristics
- Location: Diffuse elbow pain, may radiate to forearm
- Timing: Activity-related and rest pain (advanced arthritis)
- Character: Grinding, mechanical symptoms
- Function: Difficulty with ADLs (dressing, eating, hygiene)
Associated Symptoms
- Stiffness: Loss of extension common, functional arc compromised
- Weakness: Grip strength reduced, difficulty lifting
- Instability: Giving way, recurrent dislocations
- Neurological: Numbness in ulnar distribution (ring, little fingers)
Physical Examination:
Inspection and Range of Motion
- Inspect: Swelling, muscle wasting (forearm), rheumatoid nodules, surgical scars, carrying angle
- Active ROM: Flexion (normally 145 degrees), extension (0-5 degrees hyperextension), pronation (80 degrees), supination (85 degrees)
- Passive ROM: May be preserved despite pain
- Functional arc: 30-130 degrees flexion, 50 degrees pronation/supination
Specific Tests
Elbow Physical Examination
| Test | Purpose | Technique | Positive Finding |
|---|---|---|---|
| Valgus stress test | MCL integrity | Elbow at 20-30 degrees flexion, apply valgus stress | Medial opening, pain |
| Posterolateral rotatory drawer | LUCL integrity / PLRI | Supination, valgus, axial load while extending from flexion | Clunk or apprehension |
| Triceps strength | Extensor mechanism function | Resist elbow extension against gravity | Weakness indicates triceps pathology |
| Tinel's at cubital tunnel | Ulnar nerve irritation | Tap posterior to medial epicondyle | Tingling in ulnar distribution |
Pre-Operative Ulnar Nerve Assessment
Pre-operative ulnar nerve evaluation is essential. Document any pre-existing sensory or motor deficits. Consider nerve conduction studies if neuropathy is suspected. Pre-existing ulnar neuropathy is common in RA (cubital tunnel syndrome). This affects surgical planning and informed consent.
Systemic Assessment for RA Patients
- Cervical spine: Atlantoaxial instability - flexion/extension radiographs if suspected
- Other joints: Hip, knee, shoulder involvement may affect priorities
- Medications: DMARDs, biologics may need adjustment peri-operatively
- Skin quality: Rheumatoid nodules, fragile skin at surgical site
Investigations
Imaging Studies:
Plain Radiographs
Essential first-line imaging:
- AP and lateral elbow radiographs
- Assess joint space, bone quality, deformity
- Measure carrying angle, alignment
- Look for loose bodies, osteophytes
- Assess bone stock for implant sizing
CT Scan
Advanced bony assessment:
- 3D reconstruction for complex deformity
- Bone stock assessment for revision
- Templating for implant selection
- Assess previous hardware if present
- Useful for acute fractures
Radiographic Features of Elbow Arthritis:
Radiographic Classification - Elbow Arthritis
| Grade | Joint Space | Osteophytes | Bone Changes |
|---|---|---|---|
| Mild | Minimal narrowing | Small osteophytes | Minimal sclerosis |
| Moderate | Moderate narrowing | Moderate osteophytes | Subchondral sclerosis and cysts |
| Severe | Bone on bone | Large osteophytes / ankylosis | Severe destruction, bone loss |
Laboratory Studies:
- Inflammatory markers: ESR, CRP - rule out infection, assess disease activity
- Rheumatoid factor, anti-CCP: Confirm RA diagnosis
- HbA1c: Diabetes control (infection risk)
- Nutritional markers: Albumin, lymphocyte count (healing capacity)
- Joint aspiration: If any concern for infection - cell count, culture, crystals
Rule Out Infection
Infection must be excluded before proceeding with elective TEA. History of prior septic arthritis is a relative contraindication. If any suspicion, aspirate the joint and send for cell count, culture, and inflammatory markers. Proceed with surgery only when infection is definitively ruled out.
Management Algorithm
Stepwise Management of Elbow Arthritis
Management Pathway for Elbow Arthritis
Conservative treatment trial:
- Activity modification and lifestyle counselling
- NSAIDs for pain and inflammation
- Physiotherapy for range of motion and strength
- Intra-articular corticosteroid injection (limited effect)
- Disease-modifying therapy for RA (optimize medical treatment)
Options before arthroplasty:
- Arthroscopic debridement: Remove loose bodies, osteophytes
- Outerbridge-Kashiwagi (O-K) procedure: Fenestration of olecranon fossa
- Synovectomy: RA with recurrent synovitis but minimal joint destruction
- Interposition arthroplasty: Distraction with fascia lata graft (young active)
Indications for TEA:
- Failed conservative management
- Severe joint destruction with pain and functional limitation
- Low-demand patient (age greater than 60 typical)
- Accepts lifelong weight restriction
- Adequate soft tissue coverage
For most patients with end-stage elbow arthritis who meet appropriate criteria, TEA provides reliable pain relief and functional improvement.
Surgical Technique
Pre-Operative Preparation
Templating:
- Size humeral and ulnar components on radiographs
- Assess for bone loss requiring augmentation
- Plan approach based on prior surgery, soft tissue quality
Patient Optimization:
- Optimize RA disease activity (coordinate with rheumatologist)
- Consider DMARD/biologic holiday peri-operatively (controversial)
- Glycaemic control for diabetics
- Nutrition assessment and optimization
Biologic Therapy
Biologic agents (TNF inhibitors, rituximab) are associated with increased infection risk. Consider withholding 2-4 weeks pre-operatively depending on agent half-life. Balance infection risk against disease flare. Multidisciplinary decision with rheumatology.
Informed Consent:
- Weight restriction lifelong (2-5kg)
- Potential for ulnar nerve symptoms
- Infection risk (2-5%)
- Loosening and revision possibility
- Triceps weakness possibility
- Periprosthetic fracture risk
Document all consent points and ensure patient understands activity restrictions.
Complications
Complications of Total Elbow Arthroplasty
| Complication | Incidence | Risk Factors | Management |
|---|---|---|---|
| Aseptic loosening | 10-15% at 10 years | High activity, obesity, poor cement technique | Revision TEA with long stems and bone graft |
| Infection | 2-5% | RA, diabetes, immunosuppression, prior surgery | I&D vs two-stage revision vs resection arthroplasty |
| Ulnar nerve palsy | 5-10% | Pre-operative neuropathy, traction injury, direct injury | Observation (most resolve), exploration if no recovery |
| Triceps insufficiency | 5% | Poor repair, avulsion, RA with poor tissue | Revision repair, tendon reconstruction |
| Instability (unlinked) | 5-10% | Soft tissue incompetence, component malposition | Convert to linked TEA or revision |
| Bushing wear (linked) | 5-10% | High activity, non-compliance with weight restriction | Bushing exchange if components stable |
| Periprosthetic fracture | 5% | Trauma, osteoporosis, stress risers | Fixation or revision depending on site |
Infection Management
Deep infection after TEA is a serious complication. Options include: (1) I&D with polyethylene exchange for acute infection with stable components, (2) Two-stage revision with antibiotic spacer for chronic infection, (3) Resection arthroplasty (flail elbow) if unable to eradicate infection. Antibiotic suppression may be considered in selected cases.
Aseptic Loosening:
- Most common mode of failure long-term
- Ulnar component loosens more often than humeral (smaller bone stock)
- Presents with pain, decreased motion, radiographic lucency
- Revision with long-stemmed components and bone grafting
Rehabilitation
Post-Operative Rehabilitation Protocol
Protection phase:
- Posterior splint in 90 degrees flexion
- Elevation for swelling control
- Finger and wrist motion encouraged
- Wound care and monitoring
- Ulnar nerve function assessment
Gentle mobilization:
- Begin active-assisted range of motion
- Gravity-assisted extension
- Forearm rotation exercises
- Avoid resisted extension (protects triceps repair)
- Hinged brace may be used
Controlled strengthening:
- Progress to active motion
- Light resistance exercises
- Continue avoiding heavy lifting (weight restriction education)
- Functional activities for ADLs
- Continue triceps protection
Maintenance phase:
- Transition to home exercise program
- Reinforce lifelong weight restriction (2-5kg)
- Return to low-demand activities
- Regular clinical and radiographic follow-up
- Annual surveillance recommended
Weight Restriction Counselling
Lifelong weight restriction (2-5kg) is critical for TEA longevity. Patient education and compliance are essential. Repetitive or single heavy lifting accelerates bushing wear, component loosening, and periprosthetic fracture risk. This must be discussed at consent and reinforced at every follow-up visit.
Outcomes
Results and Survivorship:
Functional Outcomes:
- Significant pain relief in greater than 90% of patients
- Improvement in range of motion (typically 30-130 degree arc achieved)
- Improved ability to perform activities of daily living
- Patient satisfaction generally high when expectations managed
Comparison by Indication:
Outcomes by Primary Diagnosis
| Diagnosis | Pain Relief | ROM Improvement | Survivorship | Notes |
|---|---|---|---|---|
| Rheumatoid arthritis | Excellent | Good | 85-90% at 10 years | Best studied indication |
| Post-traumatic arthritis | Good | Fair | 75-85% at 10 years | Higher revision rate |
| Acute distal humerus fracture | Good | Variable | 80-90% at 5 years | Better than ORIF in elderly |
| Revision TEA | Fair-Good | Fair | 60-70% at 10 years | Complex, higher failure |
Factors Affecting Outcome:
- Patient selection (low-demand, compliant with restrictions)
- Surgical technique and implant position
- Bone quality and soft tissue health
- Adherence to weight restrictions
- Underlying diagnosis (RA better than post-traumatic)
Evidence Base
TEA vs ORIF for Distal Humerus Fractures in Elderly
- Randomized trial comparing TEA to ORIF for distal humerus fractures in patients over 65
- 25 patients randomized to each group
- TEA group had better functional outcomes (MEPS and DASH scores)
- Fewer complications and re-operations in TEA group
- Comparable ROM between groups
Long-Term Survivorship of Coonrad-Morrey TEA
- Retrospective review of 461 Coonrad-Morrey linked TEAs
- Mean follow-up 12 years (range 2-30 years)
- Overall survivorship: 92% at 10 years, 74% at 20 years
- Revision for any reason: 16% at 10 years
- Rheumatoid arthritis had best survivorship
Triceps-Sparing vs Triceps-Reflecting Approach
- Systematic review comparing triceps-sparing and triceps-reflecting approaches
- Triceps-sparing associated with lower rate of triceps complications
- Similar functional outcomes between approaches
- Triceps-reflecting provides better exposure for complex cases
Ulnar Nerve Management in TEA
- Systematic review of 3,259 TEAs examining ulnar nerve outcomes
- Pre-operative ulnar neuropathy present in 25% of RA patients
- Post-operative new or worsened ulnar symptoms in 10%
- Anterior transposition does not definitively prevent postoperative neuropathy
TEA for Post-Traumatic Arthritis Outcomes
- Retrospective review of 89 TEAs for post-traumatic arthritis
- Mean follow-up 8.5 years
- 75% survivorship at 10 years (lower than RA)
- Higher complication rate than primary RA TEA
- Stiffness and heterotopic ossification more common
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
Scenario 1: Rheumatoid Elbow for TEA (~2-3 min)
"A 68-year-old woman with a 30-year history of rheumatoid arthritis presents with severe right elbow pain and stiffness. She has difficulty with activities of daily living including feeding and hygiene. She has failed medical management including biologics and has had one intra-articular steroid injection with minimal relief. On examination, range of motion is 50-100 degrees, she has a 10-degree fixed flexion deformity, and there is crepitus with motion. Radiographs show bone-on-bone narrowing of the ulnohumeral joint with erosions and cyst formation. How would you manage this patient?"
Scenario 2: Distal Humerus Fracture in Elderly (~3-4 min)
"An 82-year-old woman presents after a fall with a displaced comminuted intra-articular distal humerus fracture. CT scan shows a highly comminuted C3 fracture with significant articular involvement and osteoporotic bone. She lives independently, is right-hand dominant, and has well-controlled diabetes. Her pre-injury function was normal. What are your treatment options and which would you recommend?"
Scenario 3: Post-TEA Ulnar Nerve Palsy (~2-3 min)
"A 70-year-old woman is 48 hours post total elbow arthroplasty for rheumatoid arthritis. She reports numbness in her ring and little fingers and is unable to spread her fingers apart. On examination, she has intrinsic weakness with loss of finger abduction. Her wound is healing well with no signs of hematoma. How do you assess and manage this complication?"
MCQ Practice Points
Implant Design Question
Q: What is the key difference between linked and unlinked total elbow arthroplasty? A: Linked (semi-constrained) TEA has a sloppy hinge mechanism connecting humeral and ulnar components, providing inherent stability. It allows 7-10 degrees of varus-valgus laxity. Unlinked TEA relies on intact soft tissues (collateral ligaments) for stability. Linked is preferred for RA, bone loss, instability; unlinked for primary OA with intact ligaments.
Ulnar Nerve Question
Q: What is the most common neurological complication of total elbow arthroplasty? A: Ulnar nerve palsy (5-10%). The ulnar nerve runs posterior to medial epicondyle and is at risk during medial exposure. Pre-existing ulnar neuropathy is common in RA patients (15-25%). Most post-operative palsies are neurapraxia and recover spontaneously. The nerve should be identified early, protected, and often transposed anteriorly.
Survivorship Question
Q: What is the expected 10-year survivorship of total elbow arthroplasty for rheumatoid arthritis? A: 85-90% 10-year survivorship. Rheumatoid arthritis remains the best indication for TEA with the most predictable outcomes. Post-traumatic arthritis and younger patients have lower survivorship. Most failures are due to aseptic loosening or infection.
Triceps Question
Q: Why is preservation or secure repair of the triceps mechanism critical in total elbow arthroplasty? A: The triceps is the only extensor of the elbow. Triceps insufficiency leads to significant functional deficit with inability to extend against gravity. Unlike the knee where quadriceps weakness is partly compensated, there is no alternative elbow extensor. Secure repair with transosseous sutures is essential.
Weight Restriction Question
Q: What is the recommended lifelong weight restriction after total elbow arthroplasty? A: 2-5 kg repetitive or single lifting. This is critical for implant longevity. The elbow transmits 3-4x body weight during activities, and the prosthesis is subject to significant forces. Non-compliance leads to accelerated bushing wear, loosening, and periprosthetic fracture. This must be emphasized at every follow-up.
Medicolegal Considerations
Documentation Requirements
Key medicolegal points for total elbow arthroplasty:
-
Informed consent must include:
- Lifelong weight restriction (2-5kg) and activity limitations
- Ulnar nerve palsy risk (5-10%), often temporary
- Infection risk (2-5%), may require multiple surgeries
- Aseptic loosening and need for future revision
- Triceps weakness possibility
- Periprosthetic fracture risk
-
Pre-operative documentation:
- Comprehensive neurological examination including ulnar nerve
- Document pre-existing ulnar symptoms (common in RA)
- Assessment of previous surgery, skin quality, infection history
- Radiographs and CT showing bone stock
-
Operative notes:
- Ulnar nerve identification, management, transposition if performed
- Triceps management and repair technique
- Implant details, cement technique
- Range of motion at completion
-
Post-operative care:
- Clear rehabilitation protocol provided
- Weight restriction counselling documented
- Follow-up plan with annual surveillance
Australian-Specific Considerations:
- Body mass index and manual occupation are relative contraindications
- Access to specialized revision surgery may be limited in regional areas
- Workers' compensation: Thorough documentation of occupational demands and restrictions
- Coordinate with rheumatology for biologic management in RA patients
Australian Context
Orthopaedic Training Considerations:
- Total elbow arthroplasty is a relatively low-volume procedure in Australian training programs
- AOANJRR (Australian Orthopaedic Association National Joint Replacement Registry) provides national data on TEA outcomes
- Fellowship training at upper limb specialized centers is valuable for exposure
Healthcare System Factors:
- Access to specialized upper limb surgeons may be limited in rural and remote areas
- Telehealth consultation useful for pre-operative assessment and follow-up in regional patients
- Transfer to major metropolitan center may be required for complex revision surgery
Registry Data:
- AOANJRR reports TEA outcomes annually, allowing benchmarking against national data
- Linked designs remain predominant in Australian practice
- Rheumatoid arthritis and post-traumatic arthritis are most common indications
Orthopaedic Exam Relevance:
- TEA appears in both written and viva components of the Orthopaedic examination
- Focus on indications, implant selection (linked vs unlinked), surgical approach, and complications
- Understanding evidence comparing TEA to ORIF for elderly distal humerus fractures is frequently examined
TOTAL ELBOW ARTHROPLASTY
High-Yield Exam Summary
Key Anatomy and Biomechanics
- •Elbow: Trochoginglymoid joint - ulnohumeral (hinge), radiocapitellar (pivot), proximal radioulnar
- •Primary stabilizers: Ulnohumeral joint (coronoid critical), MCL anterior bundle, LUCL
- •Secondary stabilizers: Radial head, capsule, common flexor/extensor origins
- •Ulnar nerve: Posterior to medial epicondyle in cubital tunnel - at risk during surgery
- •Functional arc: 30-130 degrees flexion, 50 degrees pronation/supination
Implant Selection
- •Linked (semi-constrained): Sloppy hinge with 7-10 degrees varus-valgus laxity - for RA, bone loss, instability
- •Unlinked (resurfacing): Relies on soft tissues - for primary OA with intact ligaments
- •Cemented fixation: Gold standard especially for poor bone quality (RA, osteoporosis)
- •Linked preferred for trauma (ligament integrity uncertain), revision, bone deficiency
Surgical Approach
- •Bryan-Morrey: Triceps-reflecting - good exposure, most commonly used for primary TEA
- •Triceps-sparing (paratricipital): Preserves extensor mechanism, limited exposure
- •Ulnar nerve: Identify early, protect, transpose anteriorly subcutaneously
- •Triceps repair: Critical for function - crossed cruciate suture through drill holes
Complications
- •Aseptic loosening: 10-15% at 10 years, ulna loosens more than humerus
- •Infection: 2-5%, two-stage revision or resection arthroplasty if cannot eradicate
- •Ulnar nerve palsy: 5-10%, most neurapraxia that recovers
- •Triceps insufficiency: 5%, significant functional deficit if occurs
- •Bushing wear: Linked TEA complication from high activity or non-compliance
Outcomes and Key Pearls
- •Survivorship: 85-90% at 10 years, 75-80% at 15 years
- •RA has best outcomes, post-traumatic arthritis has higher failure
- •Weight restriction: 2-5kg lifelong - critical for implant longevity
- •TEA vs ORIF for elderly distal humerus fracture: TEA has better outcomes (McKee RCT)
- •Document pre-operative ulnar nerve status - medicolegal importance