The elbow joint (Figures 22-1, 22-2, 22-3, 22-4, 22-5, and 22-6) is a compound synovial joint and consists of the radiohumeral (radiocapetellar), ulnohumeral (trochlear), and proximal radioulnar articulations. The movements of elbow flexion and extension occur at the ulnohumeral joint and range between 150 and 160 degrees, with between 0 and 10 degrees of hyperextension. The main flexor muscles are biceps brachii and brachialis, whereas the main extensor muscle is triceps. The movements of supination and pronation occur at the proximal radioulnar joint and the radiohumeral joint. Biceps brachii muscle and supinator muscles are the primary supinators, whereas the pronator teres is the primary pronator. The ulnar or medial collateral ligament is the major stabilizer of the elbow joint during the throwing motion. The timing of appearance of secondary ossification centers around the elbow is listed in Table 22-1. All fuse to form a singe epiphysis between 14 and 17 years of age. The distal humeral physis contributes approximately 20% to final length of humerus.
Secondary Ossification Center | Age at Appearance (y) |
|---|---|
Capitellum | 1–2 |
Radial head | 4–5 |
Inner (medial) epicondyle | 5–7 |
Trochlea | 9–10 |
Outer (lateral) epicondyle | 10–12 |
Common fused elbow epiphysis | 14–17 |
The elbow itself is richly supplied with blood, and has a robust collateral circulation, except for the lateral condyle which has an end arterial blood supply without significant arterial collateral supply. This leads to an increased susceptibility to osteonecrosis with lateral condyle fractures. The ligaments about the elbow are closely associated with growth plates, and this can lead to avulsion or displacement injury of the apophyses during periods of rapid growth, as the ligaments themselves are stronger than the physes at this time in development.
Fractures about the elbow can occur through the metaphysis (torus, buckle, or complete), physis (Salter-Harris type), or apophyses (avulsions). Eighty percent of all sport-related acute fractures in children and adolescents are of upper extremities and between 7% and 9% of these are about the elbow. Fractures about the elbow are relatively more common in boys and peak incidence is between 5 and 10 year of age.
Most elbow fractures are owing to a fall on an outstretched arm in various positions (extension type), though some fractures are owing to direct impact to the flexed elbow as in a fall while performing gymnastics and landing incorrectly (flexion type). A sudden varus or valgus force to the forearm and elbow can also result in apophyseal avulsion fractures of the lateral side or the medial side respectively. The type of fracture depends on the direction of force, the amount of energy imparted to the elbow, and the level of skeletal maturity of the athlete. Major elbow fractures are listed in Table 22-2.1–6
Fracture | Comments |
|---|---|
Supracondylar | Break above condyles of humerus. Increased risk with elbow recurvatum. Most are extension type from FOOSH. Peak at 5–8 y. Rare after age 15 y. High risk for neurovascular complications |
T-condylar | Codyles split by intra-articular extension of the T-component Caused by direct impact to flexed elbow by a fall. Peak at 12–13 y. |
Lateral condyle physis | Fracture caused by forced varus movement, as in push-off with sudden extension of elbow. Increase risk with cubitus varus elbow. High risk for avascular necrosis of lateral condyle, delayed ulnar nerve palsy. |
Lateral epicondyle | Apophyseal avulsion. Similar mechanism as lateral condyle fracture. Extremely rare. |
Medial condyle physis | Caused by direct fall on outstretched arm. Rare before age 8 y. |
Medial epicondyle | Apophyseal avulsion fracture. Seen with throwing, sudden forceful valgus stress during late cocking, early acceleration phase of pitching in baseball. Peak at 11–12 y. High association with elbow dislocations. Fractures epicondyle may get trapped in the joint. |
Olecranon | Caused by overload of triceps. Rarely seen as an isolated fracture. Most are associated with other elbow fractures. |
Radial head and neck | Neck fractures more common in children. Caused by direct impact or FOOSH. Check for associated distal radioulnar joint injury–Essex–Lopresti injury in which the athlete presents with pain at elbow and wrist. |
The athlete presents with a history of a fall on outstretched arm or a sudden, forceful impact to the elbow. The elbow with an acute fracture is painful, swollen, and tender. The athlete is reluctant to move the elbow and typically will hold the injured arm supported by the other hand. In displaced fractures, there will be apparent deformity, whereas nondisplaced fractures will only have mild swelling and can be initially difficult to recognize clinically and often by x-ray as well. Given the history that can result in elbow fractures, the physician’s assessment should be guided by a high index of suspicion, in cases in which findings of examination are minimal. Always assess perfusion, arterial pulses, and sensation to touch distally. Assess wrist and finger movements and strength. If a fracture is apparent or suspected, the elbow and the arm should be placed in a well-padded splint in neutral position (elbow at 90-degree flexion) with an arm sling (Figure 22-7) and the standard x-rays should be obtained before further manipulation of the elbow.
Standard x-rays of the elbow include AP view with elbow in extension, and a lateral view with the elbow at 90-degree flexion in neutral position. In the skeletally immature athlete, always obtain comparison views of the uninjured side. On the AP view, look for metaphyseal or epiphyseal fractures. Look for any asymmetry of the ossification center of the lateral condyle. On the lateral view, look for the normally well-defined teardrop appearance just above the capitellum, and posterior fat pad sign (Figure 22-8). For adequate evaluation of condyle fractures, varus or valgus stress views may be indicated.
Initial treatment consists of immobilization in a well-padded posterior splint, a sling, ice, and elevation, with repeat neurovascular checks and orthopedic referral (Box 22-1). All displaced fractures, open fractures, and those associated with any neurovascular signs must be seen by orthopedic surgeon emergently. The athletes can expect to return to sports in approximately 8 to12 weeks in most cases when they have no elbow pain, and have full range of pain free elbow movements.
Fractures about the elbow |
Elbow dislocations |
Forearm bone fractures |
Complete tear of ulnar collateral ligament of thumb metacarpophalangeal joint |
Displaced fracture of scaphoid |
Nonunion of scaphoid fracture |
Fractures of other carpal bones |
Scapholunate dissociation |
Closed flexor digitorum profundus avulsions |
All open fractures of the hand bones |
Displaced and angulated fractures of the metacarpals and phalanges |
Thumb metacarpal fractures |
Failure of closed reduction of dislocated metacarpophalaeal and interphalangeal joints |
Elbow dislocations are relatively rare in childhood, most are posterior, and account for <6% of pediatric elbow injuries. Most pediatric age elbow dislocations are seen in adolescent boys (70%) at 13 to 14 years of age. Up to 50% of elbow dislocations are associated with fractures of the medial epicondyle. Monteggia fractures are a variant of elbow dislocations and include a fracture of the ulna with a radial head dislocation.
Posterior dislocations occur with hyperextension of the elbow as in a fall on an extended outstretched arm.
The athlete presents with a history of fall on outstretched arm and a sudden onset of severe pain and swelling of the elbow. The deformity is apparent on examination. The olecranon will be prominent, the elbow is held in flexion, and the injury is usually closed. The adolescent is reluctant to move the arm. A meticulous neurovascular assessment must be done. Clinical differentiation of posterior elbow dislocation from supracondylar fracture may be difficult.
The athlete should be seen immediately in the emergency department and orthopedic consultation should be obtained. After x-rays have confirmed that there are no associated fractures, closed reduction is attempted under appropriate analgesia (Figure 22-10). The elbow usually is easily reducible and stable. Postreduction x-rays should be obtained. The arm is immobilized in a splint for 3 weeks with orthopedic follow-up.
Figure 22-10
Technique for closed reduction of posterior dislocation of the elbow. With the athlete lying prone on the examination table and the arm with dislocated elbow hanging over the edge of the table as shown, weight (5–10 lbs) is suspended with a strap around the wrist for approximately a period of 5 to 10 minutes by which most posterior dislocations tend to reduce.
UCL sprains may result in partial-thickness or full-thickness complete tear. A full-thickness tear results in elbow instability. Acute sprains of UCL are rare in young children and most are seen in adolescents nearing skeletal maturity.
The ulnar or medial collateral ligament, particularly the anterior band provides stability to the elbow in conjunction with the bony anatomy, and it acts as a restraint to valgus stress of the elbow, especially during overhead throwing motion. Ulnar collateral ligament injury is most commonly associated with valgus extension overload during the pitching or throwing motion.
The athlete will present with sudden onset medial elbow pain and tenderness, and in some cases may have paresthesias, pain, or weakness in the ulnar nerve distribution, over the ulnar border of the hand, ring, and little fingers. The elbow is best examined in slight flexion, with a small valgus load applies to the forearm (Figure 22-11). There will be discomfort with this maneuver and with a milking maneuver (Figure 22-12), which will localize the posterior band of the UCL.
Figure 22-12
Milking maneuver. The elbow is held at 90-degree flexion with shoulder in 90-degree abduction. The examiner places one hand over the medial elbow and with the other hand grasps the athlete’s hand and thumb. The arm is supinated and externally rotated while maintaining a valgus stress at the elbow. Assess for pain or instability of the medial elbow.
Look for osteophytes, loose bodies, and osteochondritis dissecans on standard x-rays. Instability is not always obvious on physical examination, or by static imaging, and may require stress films. MRI or MR arthrogram may be indicated to delineate the degree and nature of the ulnar collateral ligament injury, and associated soft tissue and cartilage injuries about the elbow.
Grade 1 (stretch) and 2 (partial-thickness) sprains are initially treated conservatively. The usual treatment is rest, ice, a short period of sling use, and NSAIDs. Once the athlete has no pain in the elbow, range of motion, and progressive strengthening exercises are started. Six weeks after injury, the stability of the elbow is reassessed. If a grade 3 (full-thickness) sprain is diagnosed, and the athlete wishes to return to competitive throwing, a surgical reconstruction is often recommended. In those with a partial-thickness tear but persistent pain and dysfunction despite 3 months of conservative care, surgical reconstruction may be considered. Many young athletes will undergo collateral ligament reconstruction to improve function in the elbow, and at the same time address other coexisting elbow pathology through the arthroscope, such as loose bodies, cartilage injury, and posterior osteophytes.7–9
Fractures of the forearm can involve radius, ulna, or both. Most are distal radius or ulnar physeal or metaphyseal fractures. Physeal fractures are classified based on the Salter-Harris classification of acute growth plate fractures (see Chapter 19). Metaphyseal fractures can be incomplete (torus or greenstick) or complete fractures.
Distal radius fractures comprise 8% to 15% of pediatric fractures. Distal radius fractures can occur with either a fall on outstretched arm or a direct blow to the distal forearm and are seen in such activities as roller skating, skate boarding, and inline skating. The incidence of fractures of the distal metaphysis of the radius peaks in adolescents during peak growth velocity. Distal metaphyseal fractures can be torus, buckle, or complete fractures. Fractures of the distal radius physis are the most common physeal injury with a peak incidence at 13 to 14 years in boys and 9 to 10 years in girls.
Most distal ulnar fractures are metaphyseal fractures, distal ulna physeal fractures are rare. Distal ulnar fractures are most common in ice hockey and other stick sports such as lacrosse and field hockey. Metalphyseal fractures of both the radius and ulna peak at 11 to 12 year of age in girls and 13 to 14 years in boys. Galleazi fractures are forearm fractures with displacement or instability of the distal radioulnar joint.
Most are because of a fall on an outstretched extended hand, and rarely are because of a direct impact to the arm or wrist.
The young athlete will present with pain around wrist and distal forearm after a fall, usually with a swollen tender wrist and limited motion of the wrist caused by pain. Nondisplaced, torus, and greenstick fractures may go unrecognized for days until the athlete is seen because of continued wrist pain and x-ray is obtained. Deformity of the distal forearm and wrist will be apparent with significantly displaced fractures.
A pronator fat pad sign on lateral x-rays is an indication of occult fracture of the distal radius metaphysis or physis. Carefully look for torus or greenstick fractures.
Fractures of the scaphoid are classified into midwaist, distal pole, and proximal pole fractures (Figure 22-14).10–12 Scaphoid fractures are the most common (60%) carpal bone fractures in children accounting for 0.45% of upper extremity fractures and 2.9% of hand and wrist fractures in children. The ossific nucleus of the scaphoid appears by age 5 to 6 years and is fully ossified between the ages of 13 and 14 years. The peak incidence of scaphoid fractures in the skeletally immature adolescent is at 15 years of age and most are distal pole fractures.
The classic mechanism of injury for a scaphoid fracture is a fall on an outstretched hand with large tensile forces acting across the scaphoid.
The athlete presents with a history of fall on an outstretched hand and wrist pain exacerbated with movements. The athlete often presents late, a few weeks after the injury with complaints of an aching and stiff as well as a somewhat painful and swollen wrist. Such injuries are more common in gymnastics, as the gymnast’s wrist is repeatedly placed under a heavy load. On examination, there may be tenderness over the snuff box and over the distal pole of the scaphoid.
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