The Common Vein Copyright 2011
Definition
Fractures of the humerus are usually caused by a fall on an outstretched arm and proximal humeral fracture is a common injury in osteoporotic elderly women. Younger patients sustain proximal humeral fractures from high energy trauma. Pathologic fractures can also occur in the humerus. Distal humeral fractures occur with lower energy traumas in the elderly, while high velocity trauma and sporting accidents cause most distal humerus fractures in the young. Gunshot wounds and crush injuries are less common causes
The humeral shaft fracture patterns depend on the type of force that caused the injury. A compressive force causes proximal or distal fractures. A bending force causes transverse shaft fractures. Torsional forces cause spiral shaft fractures. Torsional forces with bending cause oblique fractures with a possible butterfly fragment.
It results in damage to the bone cortex and disruption of other soft tissue structures.
Proximal humerus fractures are classified according to the Neer Classification system. This classification system breaks down the proximal humerus into 4 parts; anatomic neck, surgical neck, greater tuberosity, and lesser tuberosity. A part is defined if there is greater than 1 cm displacement of a fracture fragment or if there is greater than 45 degrees of angulation. A one part fracture has no displaced fragments. A one part fracture can have a single or multiple fracture lines. A two part fracture is defined as either anatomic neck, surgical neck, greater tuberosity, or lesser tuberosity. The three part fractures are commonly the surgical neck with greater tuberosity, surgical neck with lesser tuberosity. The four part fractures are “Classic” or all four parts, or “valgus impacted”. Articular loss fractures are known as impression fracture and the head split. There can be an associated dislocation, these injuries are known as fracture-dislocations.
Humeral shaft fractures are classified by open vs closed, location, degree of displacement, direction and character, condition of the bone, and if there is articular extension. The locations on the shaft are the proximal, middle, or distal third of the diaphysis. The degree is either displaced or non-displaced. The direction and character are transverse, oblique, spiral, segmental, or comminuted.
Distal humeral fractures are classified as being supracondylar, transcondylar, intercondylar, condylar, capitellum, trochlea, lateral epicondyle, medial epicondyle, and supracondylar process fractures. These fractures are described anatomically. Supracondylar fractures are further subdivided based on the mechanism being either extension or flexion when the fracture occurred. Extension supracondylar fractures are more common than the flexion type. The most common type of distal humerus fracture is the intercondylar fracture.
The fracture may be complicated in the acute phase by neurovascular injury, or in the subacute or chronic phases by nonunion, malunion, infection, osteonecrosis, or osteoarthritis. Shoulder or elbow stiffness, myositis ossificans, heterotopic bone formation, and deformity are more specific for fractures of the humerus. Radial nerve injuries are common with humeral shaft fractures. The Volkmann ischemic contracture can occur with distal humerus fractures.
The diagnosis of this injury is usually made by a combination of physical examination and x-ray imaging.
Imaging includes the use of plain x-rays, and if indicated CT-scan, or MRI.
Proximal humerus fractures can be treated non-operatively or operatively. Approximately 85% of proximal humerus fractures are non-displaced and can be treated with a sling and swathe for comfort. Anatomic neck fractures may require ORIF or a shoulder hemiarthroplasty. Percutaneous fixation is an option for two-part surgical neck fractures. Greater tuberosity fractures with displacement may require ORIF with a rotator cuff repair. Lesser tuberosity fractures can be treated closed unless joint motion is compromised, then ORIF is performed. Three part fractures that cannot be reduced closed, require surgery in all patients except the severely debilitated. A hemiarthropasty can be done in older patients who can tolerate surgery. Four part fractures are treated by ORIF in young patients and by hemiarthroplasty in the elderly.
Fracture-dislocations of the proximal humerus are treated differently based on the “number of parts”. Two part fracture-dislocations are treated closed generally. Three part and four part fracture-dislocations are treated with ORIF in young patients and by hemiarthroplasty in the elderly.
Humeral shaft fractures are generally managed non-operatively with over a 90 % success rate for healing. Coaptation splints are typically used in the emergency department and then converted to a functional brace 7 to 14 days after the initial injury. Hanging casts, shoulder spica casts, and throacobrachial immobilization (Velpeau dressing) are also used. Patients usually use a sling for comfort. The operative indications for humeral shaft fractures are multiple trauma, inadequate trial of non-operative treatment, pathologic fractures, vascular injuries, “floating elbow”, segmental fractures, if intraarticular extension, bilateral humeral fractures, and open fractures. Surgery can be performed with plates and screws, an intramedullary nail, or with an external fixation device.
Distal humerus fractures are treated to achieve an anatomic articular reduction with a stable articulation surface. Extension type supracondylar fractures are treated nonoperatively with a long arm splint then a posterior splint if there is minimal or no displacement of fragments. Severely comminuted fractures in the elderly can be treated nonoperatively as well. Operative indications include displacement, vascular compromise, and if the fracture is open. Extension type supracondylar fractures are treated with plate and screw fixation or total replacement. Flexion type supracondylar fractures are treated nonoperatively if minimally displaced in a posterior elbow splint, but are treated with plate and screw fixation or total elbow replacement if displacement of fracture fragments is present. Transcondylar fractures are treated nonoperatively for minimally displaced fractures. Operative indications include displaced fractures, open fractures, or unstable fractures. Transcondylar fractures are surgically repaired with plate and screw fixation or total elbow arthroscopy. The intercondylar fractures are the treated with casting, traction, or gravity traction making a “bag of bones” for nondisplaced fractures or the elderly. Operative repair of intercondylar fractures includes ORIF or total elbow arthroplasty. Condylar fractures are treated nonoperatively for nondisplaced fractures and with screw fixation for displaced fractures. Capitellum fractures are treated by immobilization for 3 weeks in a posterior splint for nondisplaced fractures. ORIF or excision of fragments can be performed for displaced capitellum fractures. Medial epicondyle fractures are treated with a posterior splint with a forearm pronated and the wrist and elbow flexed for 2 weeks if the fragment is minimally displaced. Excision or ORIF can be performed if there are displaced fragments, elbow instability, or ulnar nerve symptoms. Fractures of the supracondylar process are treated nonoperatively with a posterior elbow splint in flexion.
The Normal Proximal Humerus |
|
Courtesy Ashley Davidoff MD 46662c01.800 |
References
Davis MF, Davis PF, Ross DS. Expert Guide to Sports Medicine. ACP Series, 2005.
Elstrom J, Virkus W, Pankovich (eds), Handbook of Fractures (3rd edition), McGraw Hill, New York, NY, 2006.
Koval K, Zuckerman J (eds), Handbook of Fractures (3rd edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Lieberman J (ed), AAOS Comprehensive Orthopaedic Review, American Academy of Orthopaedic Surgeons, 2008.
Moore K, Dalley A (eds), Clinically Oriented Anatomy (5th edition), Lippincott Williams & Wilkins, Philadelphia, PA, 2006.
Wheeless’s Textbook of Orthopaedics: Fractures of the Humerus Menu (http://www.wheelessonline.com/ortho/fractures_of_the_humerus)