Elbow Fractures
Anatomy and Classification of Elbow Fractures
Fractures about the pediatric elbow are common; they account for 5%–10% of all fractures in children. The unique anatomy of the elbow has three articulations; the ulnohumeral joint that allows for flexion–extension, the radiohumeral joint that articulates in both flexion–extension and forearm rotation, and the proximal radioulnar joint that allows for forearm rotation. This bony relationship brings static osseous stability to the joint. Dynamic stabilizers include the medial collateral ligament, the lateral ulnar collateral ligament, and the 23 muscles that are associated with the elbow joint.
In addition, there are six secondary ossification centers in the elbow that often leads to confusion when assessing for and diagnosing pediatric elbow fractures. These centers develop in a predictable progression—capitellum, radius, medial epicondyle, trochlea, olecranon, and then the lateral epicondyle. The capitellum ossification center is first radiographically apparent at around 2 years old, and each subsequent ossification center appears sequentially about every 2 years ( Fig. 19.1 ).
Common fractures in the pediatric elbow include supracondylar humerus fractures, transphyseal distal humerus fractures, lateral condyle humerus fractures, medial epicondyle fractures, radial head and neck fractures, and olecranon fractures. Fortunately, most of these pediatric injuries heal quickly, and patients regain 90% of elbow motion and full function without the need for therapy. However, in certain elite-level athletes, early and full return of elbow motion is critical. Such sports include basketball, baseball pitching, gymnastics, and competitive cheerleading. In our experience, the most problematic fractures for this population include supracondylar humerus fractures, medial epicondylar fractures (both with and without a concomitant elbow dislocation), and olecranon stress fractures, although certainly any fracture around the elbow has the potential for causing stiffness.
Supracondylar humerus fractures
Supracondylar humerus fractures account for 50%–70% of pediatric elbow fractures, and most commonly occur between the ages of 3 and 6 years. The medial and lateral columns connect the articular surfaces of the trochlea and capitellum to the humeral shaft. The unique anatomy of the distal humerus predisposes fractures to occur in the thin area of bone between the medial and lateral columns where the coronoid fossa anteriorly and the olecranon fossa posteriorly are located. The fracture may occur in hyperextension when the olecranon acts as a fulcrum in the olecranon fossa, or may occur in flexion with an anteriorly directed force. In both cases, supracondylar humerus fractures generally occur at the level of the olecranon and coronoid fossae.
Extension supracondylar humerus fractures make up 95%–98% of supracondylar fractures and are generally classified by the Wilkins’ modification of the Gartland classification. Gartland type I fractures are nondisplaced or minimally displaced. Gartland type II fractures have posterior angulation with disruption of cortical continuity anteriorly but an intact posterior bony hinge. Type III injuries are completely displaced, with both posterior and anterior cortices fractured ( Fig. 19.2 ) . A type IV has been added, which describes a multidirectionally unstable fracture with complete loss of the periosteal hinge; these are diagnosed intraoperatively. Wilkins added subtypes A and B for type II fractures; type IIA fractures purely have extension deformity, while type IIB fractures have coronal and/or rotational malalignment.
Medial epicondyle fractures
Medial epicondyle fractures typically occur between ages 7 and 15 years, and are associated with concomitant elbow dislocations 60% of the time. The medial epicondyle is significant for the soft tissue stabilizers of the elbow that originate on it; the flexor pronator mass and the medial collateral ligament of the elbow are strong stabilizers that resist valgus instability. In addition, the ulnar nerve runs posteriorly to the medial epicondyle, making the nerve susceptible to injury in medial epicondyle fractures. There is no widely accepted classification system for medial epicondyle fractures; there does not even exist a commonly accepted definition of minimally or maximally displaced fractures, as there is poor accuracy and reliability in measuring displacement of the fragment on plain radiographs.
Olecranon stress fractures
Repeated traction forces across the olecranon physis occur in pediatric overhead throwing athletes and gymnasts. Traction apophysitis may occur, as the physis is weaker than the bone and the triceps tendon-bone insertion. With repeated force of the olecranon in the olecranon fossa during forceful elbow extension, a stress fracture may also develop in children whose olecranon physis has closed or is near closing. There is no classification system for these fractures.
Preoperative Evaluation and Treatment for Elbow Fractures
Although it is tempting to immediately examine the injured elbow, this should be delayed until the end of the examination. Evaluation of any injury in the elbow begins with palpation and inspection of the bones and joints above (humerus and shoulder) and below (forearm, wrist, and hand) the obviously injured area. The “floating elbow” variant (supracondylar humerus fracture with ipsilateral forearm fracture) occurs in approximately 5% of supracondylar humerus fractures and is associated with higher morbidity and complications, such as neuropraxia, pulselessness, and compartment syndrome. The skin should always be carefully inspected to rule out the possibility of an open fracture. In addition, signs of severe soft tissue injury such as ecchymoses, substantial swelling, and puckering should be noted as this may aid in determining the timing and urgency of treatment. Substantial global elbow swelling in the setting of a medial epicondyle fracture should alert the clinician to the possibility of a spontaneous relocation of a pediatric elbow dislocation.
A complete and thorough neurovascular exam should be performed. Because of young age and anxiety, some children may be uncooperative with the examination after an acute elbow injury and therefore parents should be warned that there is a possibility of discovering a neurologic injury later. Examining the contralateral uninjured extremity is helpful to establish baseline cooperation in the young, anxious child. Peripheral nerve injuries occur in 10%–15% of pediatric supracondylar fractures; the anterior interosseous and median nerve are the most commonly injured in extension-type supracondylar humerus fractures although the radial nerve can also be injured. Ulnar nerve injuries occur most commonly with flexion-type supracondylar fractures and medial epicondyle fractures. Elbow dislocations often occur in the setting of medial epicondyle fractures and have had reported iatrogenic injury of the median and ulnar nerves after reduction of the dislocation due to entrapment of the nerve in the joint.
It is always possible to establish the vascular status of an injured limb, even in an uncooperative child. In addition to noting warmth, color, and capillary refill of the ipsilateral hand, the presence of a palpable radial pulse can be ascertained on physical examination. If the presence of a palpable radial pulse is in doubt, use of a doppler ultrasound is helpful in ascertaining the presence of patent arterial flow to the hand. Nonpalpable pulses have been reported in 6% of Gartland type 3 supracondylar humerus fractures and may be due to spasm, extrinsic constriction, incarceration in the fracture site, thrombosis, or laceration. Although vascular injury is uncommon with medial epicondyle fractures and elbow dislocations, careful vascular assessment is mandatory, especially after reduction of an elbow dislocation.
The final step in evaluating the child with an elbow fracture is to carefully and gently palpate the injured elbow; performing this step first will lead to pain and the child’s subsequent distrust of the examiner. Supracondylar fractures have tenderness both medially and laterally over the supracondylar ridges. Lateral condyle fractures have tenderness over the lateral ridge, and medial epicondyle fractures have tenderness medially. Careful palpation of both the olecranon and radial neck will also help to assess for a fracture in those areas. Valgus instability that can be seen in the setting of a medial epicondyle fracture is often only possible to elicit when the child is completely anesthetized. Olecranon apophyseal stress fractures have tenderness over the apophysis, but patients have intact active elbow extension; patients with displaced olecranon fractures are unable to extend their elbow.
Good quality radiographs of the injured elbow are essential to diagnosis. True anteroposterior (AP) and lateral orthogonal views must be obtained, with oblique views if a lateral condyle humerus fracture or occult fracture is suspected. Contralateral radiographs of the uninjured elbow can be helpful to differentiate incomplete ossification from a fracture in an unossified elbow. Any forearm or wrist tenderness should alert the clinician to the possibility of an ipsilateral forearm or wrist fracture, and orthogonal forearm or wrist radiographs should be obtained.
Surgical Steps, Indications for Immobilization, and Postoperative Rehabilitation for Elbow Fractures
The surgical technique for elbow fracture varies for each type of fracture.
Supracondylar humerus fractures
Surgical steps
Closed reduction and percutaneous pinning is the mainstay of treatment of displaced pediatric supracondylar humerus fractures. With the child supine under general anesthesia, longitudinal traction is first applied to obtain length. Coronal plane malalignment and displacement is then corrected, then a gentle hyperflexion movement with an anteriorly directed force over the distal fragment reduces the fracture. Two or three percutaneous laterally based entry pins are then placed retrograde, entering the capitellum and exiting the medial cortex of the distal humerus ( Fig. 19.3 ). Occasionally, fracture pattern or fracture instability dictates the need for a medial entry pin, but this pin does endanger the ulnar nerve as it courses posterior to the medial epicondyle ( Fig. 19.4 ). Rarely, an open reduction is performed for an irreducible fracture or for neurovascular exploration. The child is immobilized for 3–4 weeks in a long arm splint or cast, and the pins are then removed in the clinic.
Indications for immobilization
Postoperatively after a supracondylar humerus fracture, children are placed in a long arm splint or cast with their elbow flexed less than 90 degrees, especially if a medial pin was placed that may cause a traction injury to the ulnar nerve. Supracondylar humerus fractures that are treated nonoperatively are generally immobilized in a long arm cast flexed to 90 degrees. Children are immobilized in the long arm splint or cast for 3–4 weeks.
Postoperative rehabilitation
The week the splint or cast is removed, children are given a home exercise program due to frequent elbow stiffness, particularly in elbow extension. The home exercise program consists of early active assistive range of motion (ROM), early active ROM, and early gentle passive ROM focusing on elbow extension but also including elbow flexion, forearm protonation, and forearm supination. Children are to complete the home exercise program three times a day for 1 month. Most children only require a home exercise program for elbow ROM and do not require any further rehabilitation. Goals for the postoperative phase for most children are a pain-free elbow, a functional elbow, and a stable elbow, which are obtained with only a home exercise program.
However, for pediatric athletes, the goals are unique. For pediatric athletes, end ROM in elbow extension is necessary. Basketball players require full elbow extension for success in free throws. Gymnasts need full elbow extension for elbow extension symmetry on rings and symmetrical weight bearing while tumbling. Cheerleaders require full elbow extension to perform stunts where holding a formation safely needs to have full elbow extension. For these athletes, elbow symmetry is also necessary when tumbling safely. These athletes are not able to participate to their full potential in their sports if they do not achieve full extension of their elbow. With an increase in high-level pediatric athletes, the need for full elbow extension is more often seen. For pediatric athletes, their sport is often their most meaningful “occupation” in their life. In these cases, serial orthoses to obtain end range of elbow extension may be necessary. Serial orthoses are beneficial for improving elbow extension, because it maintains shortened tissue at maximum tolerable length without stress, and adjustments are easily made to the orthoses.
Serial elbow extension orthoses are fabricated with maximum elbow extension and the forearm in neutral. An elbow extension orthosis can be fabricated with Aquaplast or a similar material and is applied to the radial surface of the forearm and humerus ( Fig. 19.5 ). Depending on the age of the child, thicker material such as 1/8 in. is required for older children; whereas, 1/16 in. can be used for younger children with an additional bar for reinforcement. The orthosis should allow for easy movement of the shoulder and wrist. The orthosis should be worn for 23 hours a day for ideal results. Once a week, the orthosis is remolded for increased extension. Before remolding, passive range of motion (PROM) to the elbow in extension and moist heat is recommended to achieve maximum stretch. Four to six weeks of orthosis adjustments are required depending on individual improvements and compliance. Once end ROM is achieved, extension is maintained with a nighttime orthosis for 3 months ( Table 19.1 ).
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