. Humeral shaft fractures. Musculoskeletal Medicine for Medical Students. In: OrthopaedicsOne - The Orthopaedic Knowledge Network. Created Jan 15, 2012 10:50. Last modified Mar 04, 2013 01:50 ver.17. Retrieved 2019-05-24, from https://www.orthopaedicsone.com/x/W4GTB.
Humeral Shaft (Diaphysis) can fracture following injury to the arm due to a direct fall or blow, automobile injury, gun shot wound, missile injury, and rarely, due to ball-throwing injuries. It may also result following low-energy injury or fall in patients with significant osteoporosis or skeletal metastases.
Structure and function
The portion of humerus stretching between upper border of pectoralis major muscle insertion (just below the surgical neck) to supracondylar ridge distally, constitutes the humeral shaft. On cross-section, the proximal ½ of shaft is cylindrical, whereas distally, it tapers to become triangular. The medullary canal, likewise, tapers and ends just superior to Olecranon fossa, which is in contrast to femoral and tibial metaphysic, which widens distally. This is important to prevent distraction of femoral shaft fractures during antegrade intra-medullary nailing.
The humeral diaphysis has abundant soft tissue envelop and receives rich blood supply from perforating branches of the brachial artery, which aids in fracture healing. Branches of brachial artery constitute the main blood supply to humeral diaphysis. The main nutrient artery enters the humerus medially, distal to midshaft and provides intra-medullary and periosteal circulation. Soft tissues surrounding the humeral shaft are divided into two compartments by medial and lateral muscular septa. The biceps brachii, coracobrachialis, and brachialis muscles (elbow flexors); median nerve, musculocutaneous nerve and brachial vessels occupy the anterior compartment, whereas, the triceps muscle (elbow extensors) and the radial nerve are contained in the posterior compartment. At the level of middle 1/3rd of humeral shaft, the radial nerve runs in the radial groove (spiral groove or radial sulcus) and remains in contact with the posterior surface for about 6.5cms. It exits the posterior compartment and enters the anterior compartment by piercing the lateral intermuscular septum. The ulnar nerve, proximally, lies in the anterior compartment and pierces the medial intermuscular septum to enter the posterior compartment near the distal 1/3rd of the humerus.
In US, it equally affects all age groups. A bimodal distribution with peaks in the third and seventh decades reported in European population.
It is a common injury, representing 3% to 5% of all fractures in Adults. 8% of Humeral Shaft fractures are Pathological.
It also represents 3% of all fractures in Children and constitutes less than 10% of humeral fractures in children. In children, they are more common under age 3 and above age 12.
Mechanism Of Injury:
Direct trauma to the arm resulting in transverse or comminuted fractures of the shaft is the most common mode of injury in these patients.
Spiral or Oblique fractures result from indirect injuries - a fall on an outstretched arm, especially in elderly patients. Rarely, ball-throwers can get this fracture pattern following violent muscular contractions of the arm muscles.
Patients usually present after a fall, direct blow or motor vehicle accident with mid-arm pain and shortened extremity.
Mid-arm area is tender to palpation and crepitus may be present on examination of arm.
Both the shoulder and elbow joints should be thoroughly evaluated, clinically and radiographically, as should the distal neurovascular status.
The incidence of concomitant radial nerve injuries is approximately 18%.
Routinely, humeral shaft fractures are descriptively classified as:
A) Based on Wound type:
75% fractures are closed.
B) Based on Location:
Radial Nerve Injury more common with Middle and Distal 1/3rd fractures .
C) Based on Degree of Displacement:
Displaced fractures through distal shaft are difficult to reduce and may show delayed healing or develop atrophic non-union.
D) Based on Anatomic Location:
1) Fracture line above the pectoralis major insertion.
In type 3: due to the deltoid pull on proximal fragment, fracture ends frequently displace and override.
E) Based on Direction:
Long Spiral, comminuted, and oblique fractures tend to heal rapidly compared to transverse fractures, due to larger available surface area.
F) Articular extension:
F) Intrinsic Condition of Bone:
Normal (Healthy Bone)
G) OTA Classification
Look for radial nerve injury in patients with middle 1/3rd to distal 1/3rd shaft fracture. Check for ECRL/ECRB, EDC, ECU, EIP, and EPL functions.
Suspect child abuse in a child presenting with humerus and other fractures, especially if younger than 18 months of age. If older than 18 months age, long bone fractures are more likely due to accidental trauma.
Look for associated injuries in form of:
Floating Elbow (Concomitant Ipsilateral Radius-Ulna and Humeral fractures).
Moreover, humeral shaft fractures may serve as a predictor of potential intra-abdominal pathology in multiply injured trauma patients.
Anteroposterior and lateral views of arm at 90° to each other, including the shoulder and elbow joints should be obtained first (a figure like this one).
DO NOT move the injured arm through the fracture site.
Traction views may be indicated in case of severely displaced fractures.
Contralateral arm radiographs aid in pre-operative planning.
Ultrasound has shown 93% sensitivity and 83% specificity in diagnosing long humeral and femoral fractures in emergency room setting.
Computed tomography (CT) and MRI scanning is rarely indicated.
Risk factors and prevention
Propensity to fall.
Child and Elderly abuse.
High Speed motor vehicle accidents.
Most cases of isolated diaphyseal humeral fractures are managed non-operatively and successfully unite with an acceptable alignment and restore the pre-injury functional level.
Nonoperative methods lead to good results with more than 90% union rates. Cast bracing appears to be the most effective.
In current practice, these injuries are treated with a hanging arm cast or a co-aptation splint for 5-15 days, which is changed to a functional brace in 5-15 days when reduction is adequate and initial fracture pain subsides.
A) Non-Operative Treatment:
With elbow flexed to 900, the arm is placed hanging in a Velcro cast with a sling placed on the radial aspect of the wrist.
An U-shaped splint with forearm suspended in cuff and collar can be used for initial stabilization.
Sling and Swathe (Velpeau’s Dressing or Thoracobrachial immobilization)
Most useful for non-compliant patients, children and elderly.
Only indicated in special circumstances as in recumbent patients and patients with large soft tissue defects.
This is the current gold standard method for conservative treatment of humeral shaft fractures. (a figure like fig 7 here)..
B) Operative (Open) Treatment:
Very few cases of Humeral Shaft Fractures need open reduction internal fixation (ORIF).
Absolute Indications for ORIF of Humeral Shaft Fractures:
Relative Indications for ORIF of Humeral Shaft Fractures:
Two basic ORIF techniques are used:
(1) Compression plate and screw fixation:
If ORIF is indicated, plate osteosynthesis is the gold standard
(2) Intramedullary nailing:
Two types of intramedullary nails are available:
C) External Fixation
External fixation is used in open humerus fractures as in burns, gunshot wounds or severe comminuted open injuries with defects of skin, bone, or soft tissue. Other indications may include osteitis and infected non-union and only when other means of management are not applicable or appropriate.
Complications include pin tract infection, neurovascular injury, and nonunion.
Union takes approximately 8 weeks but full recovery may take up-to a year.
Fracture healing rates for this injury are >95%, even with non-operative treatment
1) Radial nerve injury
Occurs in up to 18% of cases.
2) Vascular injury
Laceration of brachial artery with sharp ends of fracture fragments or with open penetrating injuries,
Occurs in up to 15% of cases
Incidence of malunion, mainly anterior angulation and varus variety is high.
Geriatric humeral shaft fractures can be prevented by fall prevention programs focusing on individual’s balance, strength, and conditioning to improve gait and safe ambulation. E.g. practicing tai chi has been shown to reduce the risk of falls and improve bone health.
Sir John Charnley wrote, “It is perhaps the easiest of the major long bones to treat by conservative methods".
Seen in Snowboarders, Skiers, Baseball Pithcers, and Softball players. Snowboarders more often fracture the left humerus at the diaphysis.
When it results in spiral/oblique fracture pattern and known as “ball-thrower’s fracture”. These fairly rare injuries tend to affect arm wrestlers and throwing athletes, especially pitchers, javelin throwers and discus throwers.
Humeral Shaft Fractures; Functional bracing; mid-shaft; radial nerve injury.
Develop a habit to assess distal neurovascular function in all long bone and extremity trauma.
In case of Humeral Shaft fractures, learn to aptly rule out radial nerve palsy by assessing function of the Extensors in fore-arm (ECRL/ECRB, EDC, ECU, EIP, and EPL).