Distal Humerus Fractures - Trauma

summary
- Distal Humerus Fractures are traumatic injuries to the elbow that comprise of supracondylar fractures, single column fractures, column fractures or coronal shear fractures.
- Diagnosis is made with plain radiographs of the humerus and elbow. CT scan is helpful for intra-articular assessment and operative planning.
- Treatment is usually open reduction and internal fixation.

Epidemiology
- Incidence
  - accounts for 0.5-7% of all fractures
  - accounts for 30% of elbow fractures
- Demographics
  - most common in young males and older females
- Anatomic location
  - distal intercondylar fractures are the most common fracture pattern

Etiology
- Forms
  - distal humerus fractures are traumatic injuries that include
    
    supracondylar fractures
    
    single column (condyle) fractures
    
    bicolumn fractures
    
    coronal shear fractures
- Pathophysiology
  - mechanism
    
    low energy falls in elderly
    
    high energy impact in younger population
  - pathoanatomy
    
    elbow position affects fracture type
    
    elbow flexed < 90°
    
    axial load leads to transcolumnar fracture
    
    direct posterior blow leads to olecranon fracture with or without distal humerus involvement
    
    elbow flexed > 90°
    
    may lead to intercondylar fracture
- Associated injuries
  - elbow dislocation
  - terrible triad injury
  - floating elbow
  - Volkmann contracture
    
    results from missed forearm compartment syndrome

Anatomy
- Osteology
  - elbow is a hinged joint
  - trochlea
    
    articulates with sigmoid notch
    
    allows for flexion and extension
  - capitellum
    
    articulates with proximal radius
    
    allows for forearm rotation
- Muscles
  - common flexors (originate from medial epicondyle)
    
    pronator teres
    
    flexor carpi radialis
    
    palmaris longus
    
    FDS
    
    FCU
  - common extensors (originate from lateral epicondyle)
    
    anconeus
    
    ECRL
    
    ECRB
    
    extensor digitorum comminus
    
    EDM
    
    ECU
- Ligaments
  - medial collateral ligament
    
    anterior bundle originates from distal medial epicondyle
    
    inserts on sublime tubercle
    
    primary restraint to valgus stress at the elbow from 30-120°
    
    tight in pronation
  - lateral collateral ligament
    
    originates from distal lateral epicondyle
    
    inserts on crista supinatorus
    
    stabilizer against posterolateral rotational instability
    
    tight in supination
- Nerves
  - ulnar nerve
    
    resides in the cubital tunnel in a subcutaneous position below the medial condyle
  - radial nerve
    
    resides in the spiral groove 15cm proximal to distal humeral articular surface
    
    runs between brachioradialis and brachialis proximal to elbow
    
    divides into PIN and superficial radial nerve at the level of the radial head

                        Classification
                    
                        Can be classified as
                    
                        supracondylar fractures
                    
                        distal single column fractures 
                    
                        subclassified using Milch classification system (see table)
                    
                        lateral condyle more common than medial
                    
                        distal bicolumnar fractures 
                    
                        classified using Jupiter classification system (see table)
                    
                        5 major articular fragments have been identified
                    
                        capitellum/lateral trochlea
                    
                        lateral epicondyle
                    
                        posterolateral epicondyle
                    
                        posterior trochlea
                    
                        medial trochlea/epicondyle
                    
                                            AO/OTA Classification of Distal Humerus Fractures
                                        
                                            Type A
                                        
                                            Extra-articular (supracondylar fracture), 80% are extension type; epicondyle
                                        
                                            Type B
                                        
                                            Intraarticular- Single column (partial articular-isolated condylar, coronal shear, epicondyle with articular extension)
                                        
                                            Type C
                                        
Intraarticular- Both columns fractured and no portion of the joint contiguous with the shaft (complete articular)
                                        
                                            Each type further divided by degree and location of fracture comminution
                                        
                                            Milch Classification of Single Column Condyle Fractures
                                        
                                            Milch Type I
                                        
                                            Lateral trochlear ridge intact
                                        
                                            Milch Type II
                                        
                                            Fracture through lateral trochlear ridge
                                        
                                            Jupiter Classification of Two-Column Distal Humerus Fractures
                                        
                                            High-T
                                        
                                            Transverse fx proximal to or at upper olecranon fossa
                                        
                                            Low-T
                                        
                                            Transverse fx just proximal to trochlea (common)
                                        
                                            Y
                                        
                                            Oblique fx line through both columns with distal vertical fx line
                                        
                                            H
                                        
                                            Trochlea is a free fragment (risk of AVN)
                                        
                                            Medial lambda
                                        
                                            Proximal fx line exists medially
                                        
                                            Lateral lambda
                                        
                                            Proximal fx line exists laterally
                                        
                                            Multiplane T (not pictured)
                                        
                                            T type with an additional fracture in coronal plane

Presentation
- Symptoms
  - elbow pain and swelling
- Physical exam
  - gross instability often present
    
    avoid ROM due to risk of neurovascular damage
  - neurovascular exam
    
    check function of radial, ulnar, and median nerves
    
    check distal pulses
    
    brachial artery may be injured
    
    if pulse decreased, obtain noninvasive vascular studies and consult vascular surgery if abnormal
  - monitor carefully for forearm compartment syndrome

Imaging
- Radiographs
  - recommended views
    
    AP
    
    lateral
  - additional views
    
    obtain wrist radiographs if elbow injury present or distal tenderness on exam
    
    oblique and traction radiographs may assist with surgical planning
    
    specifically used to evaluate if there is continuity of the trochlear fragment with the medial epicondylar fragment, this can influence hardware choice
- CT
  - often obtained for surgical planning
  - especially helpful when shear fractures of the capitellum and trochlea are suspected
- MRI
  - usually not indicated in acute injury

Treatment
- Nonoperative
  - cast immobilization
    
    indications
    
    nondisplaced Milch Type I fractures
- Operative
  - closed reduction and percutaneous pinning (CRPP)
    
    indications
    
    displaced Mich Type I fractures
  - ORIF
    
    indications
    
    supracondylar fractures
    
    intercondylar / bicolumnar fractures
    
    Milch Type II fractures
  - total elbow arthroplasty
    
    indications
    
    distal bicolumnar fractures in elderly patients

Techniques
- Cast Immobilization
  - technique
    
    immobilize in supination for lateral condyle fractures
    
    immobilize in pronation for medial condyle fractures
- ORIF
  - approach
    
    posterior superficial approach
  - exposures
    
    triceps-splitting (Campbell)
    
    technique
    
    split triceps tendon in midline down to olecranon
    
    triceps-sparing (paratricipital, Alonso-Llames, medial and lateral windows)
    
    indications
    
    extra-articular fractures
    
    fractures with a simple articular split
    
    technique
    
    elevate triceps from the humerus using medial and lateral windows
    
    can be converted to olecranon osteotomy if needed
    
    olecranon osteotomy
    
    indications
    
    complex intra-articular fractures
    
    fractures with a coronal splint
    
    contraindications
    
    total elbow arthroplasty is planned/may be required
    
    technique
    
    perform chevron (apex distal) osteotomy
    
    fixation of osteotomy performed using a combination of screws, K wires, tension band or plate
    
    complications
    
    AIN nerve injury
    
    check ability to flex thumb interphalangeal joint in recovery
    
    symptomatic hardware
    
    triceps-reflecting (Bryan-Morrey)
    
    technique
    
    reflect triceps tendon, forearm fascia, and periosteum off the olecranon from medial to lateral
    
    repair through transosseous drill holes
    
    immobilize to protect triceps repair for 4-6 weeks postoperatively
    
    triceps-reflecting anconeous pedicle (O'Driscoll)
    
    technique
    
    elevate anconeous subperiosteally from proximal ulna
    
    lateral muscles interval
    
    technique
    
    elevate the ECRB and part of the ECRL off of the supracondylar ridge
  - fixation
    
    perform provisional reduction with k-wires
    
    if metaphyseal injury is not comminuted, reducing one column to the metaphysis first may be beneficial
    
    perform fixation of articular fragments with countersunk/headless screws
    
    consider using positional screws when reducing trochlea to avoid narrowing it with compression
    
    perform fixation of condyles and epitrochlear ridge
    
    fix the lateral epicondyle using a tension band wire or plate
    
    fix the articular segment to the shaft using two plates in orthogonal planes
    
    new literature supports parallel plates
    
    if the ulnar nerve contacts medial hardware during flexion/extension, can perform an ulnar nerve transposition
    
    literature does not support decreased ulnar nerve symptoms with transposition
  - postoperative
    
    splint elbow in 70° of flexion
    
    remove splint at 48 hours post-operatively and initiate ROM exercises
    
    if osteotomy performed
    
    active and active-assisted flexion and extension for 6 weeks
    
    no active extension against gravity or resistance
    
    no restrictions to rotation
    
    if osteotomy not performed
    
    active motion against gravity without restrictions
    
    no restrictions to rotation
    
    start gentle strengthening program at 6 weeks and full strengthening program at 3 months
- Total Elbow Arthroplasty
  - indications
    
    communited articular fractures in osteoporotic bone
    
    inflammatory conditions (e.g. RA)
  - complications specific to this treatment
    
    activity restrictions (e.g. can not lift more than 5 pounds)
    
    implant loosening
    
    polyethylene wear
    
    periprosthetic fracture

Complications
- Elbow stiffness
  - most common
- Heterotopic ossification
  - seen in 8%
  - routine prophylaxis is not warranted due to increased rate of nonunion in patients treated with indomethacin
- Nonunion
  - low incidence
  - avoid excessive soft-tissue stripping
- Malunion
  - avoided by proper surgical technique
    
    cubitus valgus (lateral column fractures)
    
    cubitus varus (medial column fractures)
- AIN injury
  - can be seen with olecranon osteotomy
- Ulnar nerve injury
- DJD

Prognosis
- Majority of patients regain 75% of elbow motion and strength
  - goal is to restore elbow ROM 30-130° of flexion
- Total elbow arthroplasty has rates of implant survival >75% at 10 years if used with appropriate indications
- Unsatisfactory outcomes in up to 25%
  - treatment of these fractures is complex due to
    
    low fracture line of one or both columns
    
    metaphyseal fragmentation of one or both columns
    
    articular comminution
    
    poor bone quality

AO/OTA Classification of Distal Humerus Fractures
Type A	Extra-articular (supracondylar fracture), 80% are extension type; epicondyle
Type B	Intraarticular- Single column (partial articular-isolated condylar, coronal shear, epicondyle with articular extension)
Type C	Intraarticular- Both columns fractured and no portion of the joint contiguous with the shaft (complete articular)
	Each type further divided by degree and location of fracture comminution

Milch Classification of Single Column Condyle Fractures
Milch Type I	Lateral trochlear ridge intact
Milch Type II	Fracture through lateral trochlear ridge

Jupiter Classification of Two-Column Distal Humerus Fractures
High-T	Transverse fx proximal to or at upper olecranon fossa
Low-T	Transverse fx just proximal to trochlea (common)
Y	Oblique fx line through both columns with distal vertical fx line
H	Trochlea is a free fragment (risk of AVN)
Medial lambda	Proximal fx line exists medially
Lateral lambda	Proximal fx line exists laterally
Multiplane T (not pictured)	T type with an additional fracture in coronal plane