أ. د حسان النعمانى

استاذ - رئيس الجامعة - جامعة سوهاج

كلية الطب

العنوان: العنوان الشخصى : ش الجمهورية بسوهاج -عنوان العمل : مبنى الادارة المركزية - الدور الثالث -جامعة سوهاج

إعجاب

Radial head fractures

2018-10-21 19:53:50 |

Introduction

Epidemiology
- incidence
  - 1.5-4% of all fractures
  - radial head fractures are among the most common elbow fractures (33%)
Pathophysiology
- mechanism of injury
  - fall on outstretched hand
  - elbow in extension + forearm in pronation
    - most force transmitted from wrist to radial head
Associated injuries
- 35% have associated soft tissue or skeletal injuries including
  - ligamentous injury
    - lateral collateral ligament (LCL) injury
      - most common (up to 80% on MRI)
    - medial collateral ligament (MCL) injury
    - combined LCL/MCL
  - Essex-Lopresti injury
    - distal radioulnar joint (DRUJ) injury
    - interosseous membrane disruption
  - other elbow fractures
    - coronoid fracture
    - olecranon fracture
  - elbow dislocation
    - terrible triad (elbow dislocation, radial head fracture, coronoid fracture)
  - carpal fractures
    - scaphoid fracture

Anatomy

Osteology
- elbow joint contains two articulations
  - ulnohumeral (hinge)
  - radiocapitellar (pivot)
    - 60% load transfer across elbow joint
- proximal radius
  - nonarticular portion of the radial head is a ~90 degree arc from radial styloid to Lister's tubercle (safe zone for hardware placement)
Ligaments
- lateral collateral ligament complex
  - lateral ulnar collateral ligament (LUCL)
    - primary stabilizer to varus and external rotation stress
    - deficiency results in posterolateral rotatory instability
  - radial collateral ligament (RCL)
  - accessory lateral collateral ligament
  - annular ligament
    - stabilizes proximal radioulnar joint
- medial (ulnar) collateral ligament (MCL)
  - three bundles
    - anterior bundle
      - primary stabilizer to valgus stress (radial head is second)
    - posterior bundle
    - transverse bundle
Biomechanics
- radial head confers two types of stability to the elbow
  - valgus stability
    - secondary restraint to valgus load at the elbow, important if MCL deficient
  - longitudinal stability
    - restraint to proximal migration of the radius
    - contributions from interosseous membrane and DRUJ
    - load-sharing from wrist to radiocapitellar joint, dependant on radiocapitellar surface area
    - loss of longitudinal stability occurs when
      - radial head fracture + DRUJ injury + interosseous membrane disruption (Essex-Lopresti)
        
        radial head must be fixed or replaced to restore stability, preventing proximal migration of the radius and ulnocarpal impaction

Classification

Mason Classification (Modified by Hotchkiss and Broberg-Morrey)
Type I	Nondisplaced or minimally displaced (<2mm), no mechanical block to rotation
Type II	Displaced >2mm or angulated, possible mechanical block to forearm rotation
Type III	Comminuted and displaced, mechanical block to motion
Type IV	Radial head fracture with associated elbow dislocation

Presentation

Symptoms
- pain and tenderness along lateral aspect of elbow
- limited elbow or forearm motion, particularly supination/pronation
Physical exam
- range of motion
  - evaluate for mechanical blocks to elbow motion
    - flexion/extension and pronation/supination
    - aspiration of joint hematoma and injection of local anesthesia aids in evaluation of mechanical block
- stability
  - elbow
    - lateral pivot shift test (tests LUCL)
    - valgus stress test (tests MCL)
  - DRUJ
    - palpate wrist for tenderness
    - translation in sagittal plane > 50% compare to contralateral side is abnormal
      - may be difficult to determine on exam, can get dynamic CT scan in neutral, pronation and supination for subtle injury
  - interosseous membrane
    - palpate along interosseous membrane for tenderness
    - radius pull test
      - >3mm translation concerning for longitudinal forearm instability (Essex-Lopresti)

Imaging

Radiographs
- recommended views
  - AP and lateral elbow
    - check for fat pad sign indicating occult minimally displaced fracture
- additional views
  - radiocapitellar view (Greenspan view)
    - oblique lateral view of elbow
    - beam angled 45 degrees cephalad
    - allows visualization of the radial head without coronoid overlap
    - helps detect subtle fractures of the radial head
CT
- further delineate fragments in comminuted fractures
- identify associated injuries in complex fracture dislocations

Treatment

Nonoperative
- short period of immobilization followed by early ROM
  - indications
    - isolated minimally displaced fractures with no mechanical blocks (Mason Type I)
  - outcomes
    - elbow stiffness with prolonged immobilization
    - good results in 85% to 95% of patients
Operative
- ORIF
  - indications
    - Mason Type II with mechanical block
    - Mason Type III where ORIF feasible
    - presence of other complex ipsilateral elbow injuries
  - outcomes
    - # fragments
      - ORIF shown to have worse outcome with 3 or more fragments compared to ORIF with < 3 fragments
    - isolated vs. complex
      - ORIF isolated radial head fractures versus complex radial head fractures (other associated fracture/dislocation) show no significant difference in outcomes at 4 years
      - isolated fractures trended towards better Patient-Rated Elbow Evaluation score, lower complication rate and lower rate of secondary capsular release
- fragment excision (partial excision)
  - indications
    - fragments less than 25% of the surface area of the radial head or 25%-33% of capitellar surface area
  - outcomes
    - even small fragment excision may lead to instability
- radial head resection (complete excision)
  - indications
    - low demand, sedentary patients
    - in a delayed setting for continued pain of an isolated radial head fracture
  - contraindications
    - presence of destabilizing injuries
    - forearm interosseous ligament injury (>3mm translation with radius pull test)
    - coronoid fracture
    - MCL deficiency
- radial head arthroplasty
  - indications
    - comminuted fractures (Mason Type III) with 3 or more fragments where ORIF not feasible and involves greater than 25% of the radial head
    - elbow fracture-dislocations or Essex Lopresti lesions
      - radial head excision will exacerbate elbow/wrist instability and may result in proximal radial migration and ulnocarpal impingement
  - outcomes
    - radial head fractures requiring replacement have shown good clinical outcomes with metallic implants
    - compared to ORIF for fracture-dislocations and Mason Type III fractures, arthroplasty results in greater stability, lower complication rate and higher patient satisfaction
- retrograde titanium nail reduction and stabilization
  - indications
    - not yet considered mainstream treatment as it is in the pediatric population
  - outcomes
    - small powered case studies show good outcomes

Techniques

Approaches to Radial Head
- overview
  - PIN crosses the proximal radius from anterior to posterior within the supinator muscle 4cm distal to radial head
  - in both Kocher and Kaplan approaches, the forearm should be pronated to protect PIN
    - pronation pulls the nerve anterior and away from the surgical field
- Kocher approach
  - interval
    - between ECU (PIN) and anconeus (radial n.)
  - key steps
    - incise posterior fibers of the supinator
    - incise capsule in mid-radiocapitellar plane
      - anterior to crista supinatoris to avoid damaging LUCL
  - pros
    - less risk of PIN injury than Kaplan approach (more posterior)
  - cons
    - risk of destabilizing elbow if capsule incision is too posterior and LUCL is violated, which lies below the equator of the capitellum
- Kaplan approach
  - interval
    - between EDC (PIN) and ECRB (radial n.)
  - key steps
    - incise mid-fibers of supinator
    - incise capsule anterior to mid-radiopatellar plane (have access)
  - pros
    - less risk of disrupting LUCL and destabilizing elbow than Kocher approach (more anterior)
    - better visualization of the coronoid
  - cons
    - greater risk of PIN and radial nerve injury
ORIF
- approach
  - Kocher or Kaplan approach
- plates
  - fracture involved head and neck
  - posterolateral plate placement
    - safe zone (nonarticular area) consists of 90-110 degree arc from radial styloid to Lister's tubercle, with arm in neutral rotation to avoid impingement of ulna with forearm rotation
  - bicipital tuberosity is the distal limit of plate placement
    - anything distal to that will endanger PIN
  - countersink implants on articular surface
- screws
  - headless compression screws (Hebert) if placed in articular surface
  - better elbow range of motion and functional outcome scores at 1 year compared to plate fixation
Radial Head Resection
- approach
  - Kocher or Kaplan approach
- complications after excision of the radial head include
  - muscle weakness
  - wrist pain
  - valgus elbow instability
  - heterotopic ossification
  - arthritis
  - proximal radial migration
  - decreased strength
  - cubitus valgus
Radial head arthroplasty
- approach
  - Kocher or Kaplan approach
- technique
  - metal prostheses
    - loose stemmed prosthesis
      - that acts as a stiff spacer
    - bipolar prosthesis
      - that is cemented into the neck of the radius
  - silicon replacements are no longer used
    - indepedent risk factor for revision surgery
- complications
  - overstuffing of joint that leads to capitellar wear problems and malalignment instability
  - overstuffing of joint is best assessed under direct visualization

المرفقات

1540151626 - radial head fr.pdf 0

الملحقات

Forearm fractures

2018-10-23 00:45:47 Radial head fractures

Adult Forearm Fractures Your forearm is made up of two bones, the radius and ulna. In most cases of adult forearm fractures, both bones are broken. Fractures of the forearm can occur near the wrist at the farthest (distal) end o إقراء المزيد

تواصل معي

العنوانالعنوان الشخصى : ش الجمهورية بسوهاج -عنوان العمل : مبنى الادارة المركزية - الدور الثالث -جامعة سوهاج
رقم الهاتف1002554984
الفاكس932332761
البريد الإلكترونيhassan.noaman@med.sohag.edu.eg

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