22 Humeral Shaft Fractures

10.1055/b-0040-176963

22 Humeral Shaft Fractures

Lisa K. Cannada and Ugochi Okoroafor

Introduction

Humeral shaft fractures comprise approximately 3% of extremity fractures and 20% of humerus fractures. This chapter will explore the indications for nonoperative versus operative management of humerus fractures. Several surgical approaches are described in detail. Advantages and disadvantages are different fixation methods, most commonly plates and nails, are discussed.

I. Preoperative

History and physical examination
1. Mechanism of injury:
  1. Fall from standing more common in elderly.
  2. High-energy trauma more common in younger patients.
2. Physical examination:
  1. Perform thorough sensory, motor, and vascular examination to identify any deficits.
  2. Pain, swelling, and deformity.
3. Radial nerve palsy most common:
  1. Holstein Lewis—spiral distal third shaft fracture. Commonly associated with radial nerve palsy.
Anatomy
1. Deforming forces—deltoid, pectoralis major, brachialis, coracobrachialis, brachioradialis, biceps, and triceps (▶ Fig. 22.1 a–c):
  
  Fig. 22.1 Deforming forces associated with a proximal humerus fracture (a) proximal to the pectoralis major insertion; (b) between the deltoid and pectoralis insertion; (c) and distal to the deltoid insertion.
  1. Fracture proximal to pectoralis major insertion—external rotation and abduction of the proximal fragment due to rotator cuff. Adduction of distal fragment by pectoralis major and deltoid.
  2. Fracture between pectoralis major and deltoid—adduction and internal rotation of proximal fragment by pectoralis major, teres major, and latissimus dorsi; abduction of distal fragment by deltoid.
  3. Fracture distal to deltoid—abduction and flexion of proximal fragment by deltoid, and shortening of distal fragment due to pull from triceps, biceps, and coracobrachialis.
2. Neurologic (▶ Fig. 22.2 ):
  
  Fig. 22.2 Structures at risk associated with a posterior approach (red line) to the humerus.
  1. Radial nerve—courses along spiral groove, and crosses from medial to lateral approximately 20 cm proximal to medial epicondyle.
  2. Ulnar nerve travels posterior to the medial epicondyle.
  3. Axillary nerve wraps around the proximal humerus from medial to lateral.
Imaging
1. Radiographs—anteroposterior (AP) and lateral of the humerus.
2. Always obtain X-rays of the joint above and below—shoulder and elbow AP and lateral.
3. Computed tomography (CT) not indicated in fractures of the humeral shaft.
4. Magnetic resonance imaging (MRI) typically not necessary, unless suspect pathologic fracture and trying to identify lesion.
Classification: There is not a commonly used “named” fracture classification for humeral shaft fractures.
1. Arbeitsgemeinschaft für osteosynthesefrage/orthopaedic trauma association (AO/OTA) classification:
  1. Type 12A—simple fractures:
    - i. A1—simple spiral.
    - ii. A2—simple oblique.
    - iii. A3—simple transverse.
  2. Type 12B—wedge fracture:
    - i. B2—intact wedge.
    - ii. B3—fragmented wedge.
  3. Type 12C—multifragmentary:
    - i. C2—intact segmental fracture.
    - ii. C3—fragmentary segmentalfracture.

II. Treatment

Initial management
1. Coaptation splint for initial management—U-shaped splint splint extending from axilla to the neck laterally and sling.
2. Parameters for acceptable reduction limited by small retrospective studies without correspondence to the following validated functional outcome scores: < 20 degrees anterior-posterior (sagittal) angulation, < 30 degrees varus valgus angulation, and < 3 cm shortening.
Definitive management
1. Nonoperative management
  1. Sarmiento functional brace—typically converted from a splint to brace approximately one-week postinjury when pain and swelling improve:
    - i. Affects reduction through tissue compression.
    - ii. Fracture heals by secondary bone healing.
    - iii. Indications—most closed diaphyseal fractures. Patient must be able to maintain semi-upright position during early treatment phase.
    - iv. Contraindications to bracing—axial distraction between fracture fragments, open fractures with significant soft tissue injury, bilateral humeral fractures, fractures with associated vascular injuries, ipsilateral brachial plexus injury, and nonambulatory polytrauma patients.
    - v. Radial nerve palsy is NOT a contraindication to bracing.
    - vi. Risk contributing to failure of nonoperative management—simple, transverse fractures, distal one-third fractures, proximal one-third fractures (conflicting evidence), distraction at fracture site, brachial plexus injury, large body habitus, pendulous breasts, and unbraceable arm.
    - vii. Best results with midshaft fractures, and spiral and oblique patterns.
    - viii. Need close follow-up, and follow-up radiographs should include upright films.
    - ix. Instructions to patients must be clear—tighten brace daily, some surgeons recommend sleeping upright initially until the fracture begins to heal, and physical therapy ordered for range of motion (ROM) of shoulder, elbow, wrist and hand.
2. Absolute surgical indications:
  1. Vascular injury.
  2. Floating elbow.
  3. Failure of trial of nonoperative management.
  4. Open fracture.
3. Relative surgical indications:
  1. Polytrauma patient—provides ability to bear weight.
  2. Segmental fracture.
  3. Intra-articular extension.
  4. Pathologic fracture.
  5. Brachial plexus injury.
  6. Bilateral humeral shaft fracture.
  7. Obese patient.
  8. Large breasts.
    - i. Soft tissue interposition.
4. Indications for radial nerve exploration in the setting of radial nerve palsy:
  1. Open fracture.
  2. Penetrating injury.
  3. High-energy gunshot wound (rifle or close-range shotgun).
  4. Vascular injury.
  5. Nerve deficit after closed reduction, although this is controversial.
Surgical approaches
1. Anterior approach:
  1. Proximally, dissect between the deltoid (axillary nerve) laterally and the pectoralis major (medial and lateral pectoral nerves).
  2. In the midshaft and distally, mobilize the biceps medially (musculocutaneous nerve).
  3. Deep dissection continues by splitting the brachialis to expose the humerus. The brachialis has dual innervation, allowing it to be safely divided down the center (musculocutaneous nerve medially and radial nerve laterally).
2. Anterolateral approach (▶ Fig. 22.3 a–c):
  
  Fig. 22.3 Anterolateral approach to the humerus: (a) planned skin incision; (b) superficial dissection; (c) deep dissection between the biceps and brachialis medially, and the brachioradialis laterally, to expose the humerus.
  1. Preferred for proximal third fractures, and can also be used for midshaft fractures.
  2. Interval between biceps/brachialis medially (musculocutaneous nerve) and brachioradialis laterally (radial nerve).
  3. Advantages—supine, can extend proximally via deltopectoral approach, no direct nerve exposure, and good for positioning in polytrauma patient.
  4. Disadvantages—less direct exposure of radial nerve, and not ideal for distal humerus fractures.
3. Posterior approach—triceps splitting or triceps sparing (▶ Fig. 22.4 a–c):
  
  Fig. 22.4 Posterior approach to the humerus: (a) planned skin incision; (b) deep dissection with mobilization of the triceps and clear depiction of the radial nerve; and (c) plate fixation of the humerus fracture with radial nerve lying posterior to the implant.
  1. No internervous plane.
  2. Preferred for midshaft and distal third fractures.
  3. Advantages—direct exposure of the radial nerve, and can be applied a broad plate to flat surface of distal humerus for distal fractures.
  4. Disadvantages—not ideal for proximal fractures, prone or lateral positioning required, and requires mobilization of radial nerve for plate application (▶ Fig. 22.5 a, b).
    
    Fig. 22.5 Lateral positioning in preparation of a posterior approach to the humerus: (a) Fluoroscopy is located at the head of the bed; and (b) positioning aids may facilitate reduction and imaging.
4. Lateral approach:
  1. Can be used for distal one-third fractures. This also represents an alternative approach in revision surgery.
  2. Interval between triceps and brachioradialis.
  3. Advantages—allows radial nerve exposure, extensile approach can be used, and supine positioning.
  4. Disadvantage—not commonly used, and risk to posterior antebrachial cutaneous nerve.
Fixation techniques
1. External fixation:
  1. Indications—burns, extensive soft tissue injury, grossly contaminated open fracture, associated neurovascular injury, and infected nonunion.
  2. Advantages—good for cases with extensive soft tissue compromise, and shorter operative time in setting of damage control orthopaedics.
  3. Disadvantages—nonanatomic reduction.
2. Open reduction and internal fixation (ORIF):
  1. Recommend a nonlocking large fragment (4.5 mm) narrow compression plate in most instances.
  2. Orthogonal dual plating with small fragment (3.5 mm) fixation has also been described. This provides an alternative in small patients with a narrow humerus.
  3. Minifragment plates assist with reduction.
  4. Advantages—direct visualization of fracture reduction and radial nerve, avoid shoulder pain associated with antegrade nail or elbow pain associated with retrograde nail, allows nerve exploration if needed, more predictable healing, anatomic reduction, and literature supports weight bearing in polytrauma patients fixed with plates.
  5. Disadvantage—longer incision, greater potential for iatrogenic nerve injury compared to intramedullary nail (IMN), load bearing, and greater risk of infection compared to IMN.
3. IMN:
  1. Relative indications—segmental fractures, osteopenic bone, pathologic fractures, fractures with extension to surgical neck, and comminuted fractures.
  2. Antegrade—proximal third or midshaft fracture.
    - i. Entry point—medial to the greater tuberosity through rotator cuff and typically just lateral to the articular surface.
    - ii. Historically, higher incidence of shoulder pain or impingement compared to ORIF. Seat nail deep to cuff to avoid impingement.
    - iii. Recent studies have shown equivalent shoulder and elbow function, union rates, and complications between nails and plates.
  3. Retrograde—distal third or midshaft fracture.
    - i. Technically difficult, especially with commercially available locked IMNs.
    - ii. Entry point proximal to olecranon fossa.
    - iii. Higher incidence of elbow pain compared to ORIF and iatrogenic fracture at insertion site.
  4. Advantages—smaller incision, immediate weightbearing, does not require direct fracture exposure, smaller bending loads compared to plate, and load sharing.
  5. Disadvantages—higher complication rate, higher risk of reoperation, risk to radial nerve with lateral to medial screws distally, risk to musculocutaneous nerve with AP screws distally, and higher incidence of shoulder or elbow pain.
Complications
1. Nonunion:
  1. Historical reports demonstrated nonunion rates of 2 to 7% with closed treatment and bracing; however, recent literature has reported nonunion rates of up to 20%.
  2. Higher rate for open fractures compared to close.
  3. Five percent rate reported with operative management.
  4. Risk factors—transverse fracture, elderly, osteoporosis, endocrine disorder, radiation therapy, and steroid use.
2. Malunion:
  1. Most commonly observed with transverse fracture pattern.
  2. More often associated with nonoperative treatment—There is conflicting evidence as to whether proximal one-third fractures have a higher rate of nonunion when treated nonoperatively.
3. Radial nerve palsy:
  1. Reported incidence from 1 to 34% (average of 12%).
  2. Increased rate of radial nerve laceration or entrapment observed with spiral distal third (Holstein-Lewis fracture).
  3. Increased incidence of neuropraxia with transverse middle third fractures.
  4. Increased rate with higher energy injuries.
  5. Overall recovery rate of 88%.
  6. Spontaneous recovery in 99% of patients managed with Sarmiento bracing.
  7. Consider a baseline electromyogram/nerve conduction velocity (EMG/NCV) after 6 weeks but average nerve recovery time is 3 to 6 months.
4. Infection after surgical fixation—Higher rate with ORIF (3%) compared to IMN (1.5%).
5. Loss of shoulder ROM—6 to 36% incidence after antegrade humeral nail.
Rehabilitation
1. Protocol for nonoperative management:
  1. Initial coaptation splint in emergency department.
  2. Change to Sarmiento functional brace within 1 to 2 weeks.
  3. May recommend upright position for sleeping initially (may sleep in chair or elevate head of bed [HOB]).
  4. Initial pendulum exercises and active elbow motion.
  5. Active shoulder exercises delayed until fracture is stable.
2. Postop protocol for ORIF:
  1. Dry dressing postoperatively or Sarmiento brace.
  2. Edema glove.
  3. Immediate shoulder and elbow ROM.
  4. Avoid shoulder abduction > 90 degrees for 4 weeks.
  5. Weightbearing per surgeon preference based on fracture pattern and plate used, typically weight bearing as tolerated (WBAT) in awake and alert patient with good fixation of an extraarticular fracture.
3. Postop protocol for IMN fixation:
  1. Dry dressing postoperatively.
  2. Edema glove.
  3. Immediate shoulder and elbow ROM.
  4. WBAT immediately postop.
Outcomes
1. Nonoperative management successful in approximately 90% of cases, especially isolated fractures.
2. Transverse and short oblique humeral shaft fractures most likely to fail nonoperative management.
3. No evidence from randomized controlled trials (RCTs) to determine whether outcome is better with surgical versus nonsurgical management.