Anatomical Overview

Pediatric bone is most vulnerable to injury about the physes (growth plates), which contribute to longitudinal bone growth. Biomechanically, open growth plates are the weakest points within the pediatric musculoskeletal system, and therefore they are more prone to injury than fully ossified bone. The surrounding ligaments are 2–3 times stronger than the physis and are therefore less susceptible to injury in the skeletally immature patient. The ossifying bones are the first areas impacted by repetitive compressive and tensile forces in gymnastics and high frequency throwing sports in young athletes.

The physis, situated between the metaphysis and epiphysis, consists of germinal cells responsible for increasing bone length. The physis is further separated into three chondrocyte zones: reserve/resting, proliferative, and hypertrophic. The reserve/resting zone, which is adjacent to the epiphysis, is known to have irregular chondrocytes, low rates of proliferation, and cartilage for bone growth, putting this zone at the greatest risk of a growth arrest injury ( Fig. 24.1 ). As the chondrocytes multiply, they become stacked and organized in the proliferative zone, where actual bone growth takes place. The cells then travel from the proliferative zone to the hypertrophic zone where they mature, degenerate, and begin calcification. The hypertrophic zone is considered the weakest zone and is at greatest risk for fracture. Overuse injuries at the hypertrophic zone can potentially lead to physeal widening, calcification, fracture, and premature closure of the physis.

Histological photograph identifying the normal human physis anatomy: (A) Epiphyseal bone, (B) resting/reserve zone, (C) proliferative zone (D) hypertrophic zone, and (E) metaphyseal bone.

Courtesy of Motomi Entomo-Iwamoto, DDS, PhD.

An apophysis is the region of the bone where tendon attaches to the ossifying cartilaginous area. The tension of the tendon attachment on the apophysis can adversely affect the formation of the bone via prolonged, high velocity loading. Inadequate healing of ossifying bone can influence the player’s future success in their sport of choice. Pediatric sports-related injuries are greatly impacted by the frequency, velocity, and direction of forces to bone, tendon, and ligaments.

Anatomy and Classification

The elbow consists of the ulnohumeral joint, radiocapitellar joint, and proximal radioulnar joint. Congruency of the elbow joint allows for extension, flexion, and axial rotation of the forearm. The ligaments of the elbow consist of the medial collateral ligament (also known as the ulnar collateral ligament or UCL), the pronator/flexor mass, and the lateral collateral ligament (also known as the radial collateral ligament or RCL), all of which contribute to elbow stability. Although the pronator/flexor mass primarily protects against valgus torque, the lateral collateral ligament complex stabilizes the radial head from posterior subluxation, in addition to protecting against varus stress. Three bundles form the medial collateral ligament: the anterior, posterior, and transverse bundles. The anterior bundle serves as the primary stabilizer against valgus and internal rotary forces, while the posterior bundle is a secondary stabilizer at 120 degrees of elbow flexion. Both of these bundles attach directly to the medial epicondyle. The transverse bundle does not contribute to stability of the elbow.

Six physes about the elbow ossify between 1 and 17 years old, with high variability regarding the exact timing of physeal closure depending on the individual. Use of the mnemonic, CRITOE (capitellum, radial head, internal/medial epicondyle, trochlea, olecranon, external/lateral epicondyle) starting at 1 year old and continuing in 2-year increments, is helpful in remembering the ossification sequence about the elbow ( Fig. 24.2 ). Ossifying physes at the elbow in the preadolescent athlete contribute to the risk of injury at the elbow. The medial epicondyle begins ossification around 6 years old, but does not fuse to the humerus until 14–17 years old, forming a vulnerable area susceptible to valgus forces, predominantly in overhead-throwing athletes. The valgus distraction (displacement or force away from the midline of the body/stress on the medial aspect of elbow) on the medial epicondyle apophysis can lead to little league elbow.

Radiograph of a 7-year-old male with labeled ossification centers about the elbow: (C) capitellum, (R) radial head, (I) internal/medial epicondyle, (T) trochlea, (O) olecranon, and (E) external/lateral epicondyle.

Courtesy of Joshua M. Abzug, MD.

Clinical Assessment

Patients with medial epicondyle apophysitis (little league elbow) present with insidious and gradual onset of medial elbow pain. The patient may report arm fatigue, particularly during the stride/early cocking and cocking stages of throwing motion ( Fig. 24.3 ). Complaints of point tenderness at the medial epicondyle, edema, and decreased throwing velocity and strength are common. Range of motion about the elbow is typically unaffected; however, a contracture greater than 15 degrees, ecchymosis, catching or a “popping” sound when throwing, is indicative of an avulsion fracture. Furthermore, as throwing involves the entire upper extremity, it is important to note that excessive external rotation of the shoulder, with concomitant decreased internal rotation of the shoulder, a condition known as glenohumeral rotation deficit (GIRD) can lead to increased valgus stress being placed on the medial aspect of the elbow. It is always important to obtain a detailed history of pitch counts and pitch types, as these injuries are often a result of repetitive high valgus forces.

Stages of throwing in baseball.

Adapted from Pinkowsky G, Hennrikus W. The throwing athlete. In: Abzug JM, Kozin SH, Zlotolow DA, editors. The Pediatric Upper Extremity . New York: Springer; 2015:1635–1666.

The diagnosis of medial epicondyle apophysitis is largely based on the clinical examination given the variability of radiographic findings. However, obtaining radiographs of the contralateral side can assist in observing if there is apophysis widening or a fracture present. ( Fig. 24.4 ). A widening of the medial epicondyle physis is indicative of early injury, and if play is continued, progression to a UCL tear or medial epicondyle avulsion fracture is possible. The older athlete may also have ulnar nerve irritation or even instability of the nerve during throwing. A study by Wei et al. showed that magnetic resonance imaging (MRI) does not commonly provide findings beyond the information obtained from a thorough history, physical examination, and plain radiographs and is therefore not necessary for true cases of medial epicondyle apophysitis.

Plain radiograph (AP view) of a 13-year-old baseball pitcher with little league elbow. Note the physeal widening of the medial epicondyle epiphysis.

Courtesy of Joshua M. Abzug, MD.

Prevention

Rest is of utmost importance in the prevention of medial epicondyle apophysitis. Pitchers are not the only athletes at risk for medial epicondyle apophysitis; catchers, volleyball players, tennis players, and football quarterbacks are also vulnerable to the valgus stresses of the overhead thrower. Such athletes should play a maximum of 8 months out of the year to allow their bodies time to rest and prevent long-term damage. Avoidance of participation in more than one game per day, playing on multiple teams, pitching and catching in the same game, and pitching for more than three consecutive days are also measures that should be taken to prevent injury. Young athletes should not play through pain. Both the Major League Baseball Association and the Little League Association support the need for young players to rest their throwing arm between games. As a preventative measure, the USA Baseball organization with collaboration from the American Sports Medicine Institute has set forth pitching guidelines and recommendations via the Pitch Smart Program ( Table 24.1 ). However, the amount and types of pitches thrown during practices are not defined or taken into account in these counts. On a positive note, the minimum age for the types of pitches has begun to be considered in their recommendations.

The importance of resting between games and making sure every young athlete has an off-season from overhead-throwing sports, at least 3 months (4 months preferred), is integral to preventing overuse injuries. Pitching more than 100 pitches in a year can significantly increase the risk for injury. Lyman et al. reported that pitchers who threw 600–800 pitches in one season were 234% more likely to sustain an elbow injury. The combination of fatigue and overuse greatly impact biomechanical form when throwing. When tired, young athletes are less likely to maintain optimal stance amplifying potential valgus elbow injury.

Additionally, overall conditioning of the core, pelvis, and shoulder girdle are essential in preventing elbow injuries in overhead-throwing athletes. The biomechanical form of the shoulder girdle should be evaluated to minimize stress on the shoulder and elbow. Proper pitching mechanics from trunk to hand and conditioning addressed in childhood can limit overuse injuries as the athlete ages.

Yukutake et al. formulated a risk evaluation tool consisting of six questions to identify risk factors for sustaining throwing injuries. The authors found the most significant indicators to be pain in the extremity during the preseason and the participation of 7 days of independent training. ( Appendix 1 ). Education is a critical component in the prevention of these injuries. Providing simple surveys, such as those composed by Yukatake et al., can bring awareness of risk factors to players, their families, and the coaching staff. Instruction on the importance of listening to one’s body and resting after experiencing pain is another necessary part of prevention, particularly in the ever-increasing competitive sporting world that often promotes a “play through the pain” mentality. General pitching guidelines do not include pitches thrown in practices and types of pitches; however, the hazards of throwing breaking pitches (ex. curveball, slider, or slurve) in young athletes are a source of continued debate ( Table 24.2 ). The technique involves greater finger involvement and wrist movement causing the ball to spin and change trajectory. In general, it is considered risky and ill-advised practice for any athlete under 14 years old to throw breaking pitches due to their decreased neuromuscular control and limited biomechanical form. Additional factors associated with prevention of injury include physical condition, nutrition, hydration, and environment. These previously mentioned factors influence the overall health and endurance of the young athlete and should not be overlooked.

Conservative Treatment

In the absence of a medial epicondyle fracture, conservative treatment of medial epicondyle apophysitis consists of 4–6 weeks of complete rest from all sports-related activities, supplemented with icing and antiinflammatory medication. Practitioners may also recommend a long-arm orthosis if compliance is in question or the patient is in substantial pain. If the radiographs demonstrate a widening of the apophysis and/or an avulsion fracture with less than 5 mm of displacement, the patient should be placed in a long arm cast or orthosis at 90 degrees of flexion with the forearm in neutral rotation for 4 weeks ( Fig. 24.5 ). A course of occupational or physical therapy is subsequently recommended to gradually rehabilitate and strengthen the affected extremity. A progressive therapy program that starts with joint mobility and range of motion (ROM), followed by the initiation of biomechanical patterns needed for throwing and ending with increasing stress to facilitate tissue adaption for throwing is recommended to fully rehabilitate the upper extremity. Return to throwing within a structured sport is not recommended for at least 3 months. The patient’s throwing mechanics and technique must be evaluated and modified as necessary during this time period.

(A) Clinical photograph of a pediatric hinged elbow brace in full extension. (B) Note the adjustable range of motion dial that can be modified as therapy progresses.

Courtesy of Joshua M. Abzug, MD.

Progressive medial epicondyle apophysitis may also lead to a partial or complete tear of the UCL, particularly in the preadolescent and adolescent populations. The conservative management of a UCL tear depends on the severity of the tear: a 1–2 week immobilization period in a hinged elbow brace may be recommended with ice and antiinflammatory medications in partial tears. Early protected motion can be introduced to limit elbow stiffness and muscle atrophy, which consists of a hinged elbow brace limiting valgus force and elbow extension/flexion motion in a pain-free arc of movement, typically 10–100 degrees. The brace facilitates realigning the tears in the collagen fibers, as the ligament begins to heal. Additionally, performing isometric exercises to the shoulder, elbow, and wrist will also assist in limiting atrophy while the affected extremity is immobilized. During the initial 2 weeks postinjury, passive shoulder external rotation should be avoided due to the valgus force it can produce on the elbow. The nonpainful arc of motion is progressed by 5–10 degrees per week in both elbow extension and flexion, with return of full motion by week 4, including forearm rotation. At approximately week 5, static and dynamic stability exercises are introduced. Advancing to isotonic exercises for the upper extremity by weeks6–7 and advanced strengthening such as the Thrower’s Ten exercises ( Appendix 2 ) ( Appendix 3 ) and plyometrics are included in the rehabilitation. Following the completion of the throwing program, stability, and isotonic exercises without return of symptoms, the athlete may start an interval sport program completely pain-free and then may return to competitive sports. Such interval sport programs consist of evaluation of sport-specific drills with the use of a plyometric ball. Return of symptoms and pain need to be monitored, particularly with increased throwing distances or frequencies throughout therapy.

Although most patients with little league elbow can be treated conservatively with success, if medial elbow pain persists or worsens there is an increased likelihood of progression to a medial epicondyle avulsion fracture or complete tear of the UCL requiring surgical intervention.

Operative Intervention

Displaced medial epicondyle avulsion fractures in overhead-throwing athletes are best treated surgically with open reduction and internal fixation. Early active range of motion (AROM) is begun at 2–3 weeks postoperatively. For cases with an associated UCL tear, reconstruction via the Tommy-John procedure or repair via the docking procedure, may be performed warranting a specific, regimented rehabilitation protocol. The general guidelines and timeline for rehabilitation following UCL surgery utilizing either an autograft or the docking surgical technique can be seen in Appendices 4 or 5 , respectively.

Rehabilitation

At the initiation of therapy, general conditioning and postural control should be assessed. In addition, it is fundamental to evaluate scapular and shoulder function, as it directly impacts the forces on the elbow. The therapist should use the nonthrowing side for comparison, given that the throwing scapula often postures anteriorly tilted, protracted, and depressed. Kyphotic posture can mask a weak serratus anterior by orienting the scapula in a protracted position. The serratus anterior is weak if the thoracic spine is extended and the scapula wings while in a quadruped position. Frequently, overhead-throwing athletes will display decreased internal rotation and horizontal adduction, described as GIRD, with an associated excessive amount of external rotation. In such instances, the use of the sleeper stretch for prevention of posterior capsule tightness is important to include as part of a comprehensive home exercise program. Evaluation of the glenohumeral joint is necessary to assess for muscle imbalances contributing to an anterior positioning of the humeral head, even after scapular realignment is addressed. Examining the position of the humeral head and palpation of the rotator cuff muscles, in addition to manual muscle testing of the shoulder, assist the practitioner in deducing the cause of protracted positioning. The pulling of the humeral head anteriorly can be attributed to pectoralis tightness, limited thoracic extension, lower trapezius weakness, posterior capsule tightness, and forward head posture. In throwing, scapular control by the upper trapezius, serratus anterior, and lower trapezius ensure that the scapula is tilted posteriorly, is elevated, and is upwardly rotated to achieve a successful throw. As such, sequential firing, scapular kinematics, stability, and control of the proximal muscles should be addressed through neuromuscular reeducation and isometric exercises for the shoulder and scapula in the early stages of therapy, before progressing to therapy for the elbow. The therapist should also assess synergistic core activation of all the abdominal muscles: rectus abdominus, transverse abdominis, obliques, and lower abdominals including the pelvic floor. Ensuring that the patient is utilizing diaphragmatic breathing as opposed to accessory breathing, which can lead to shortening of the periscapular muscles, particularly in the pediatric patient, is necessary.

Concurrently, the initial phase of rehabilitation should focus on decreasing inflammation and elbow ROM in a pain-free arc. Edema management can be addressed with cryotherapy and compression. AROM is initiated in a pain-free arc, progressing to active assistive range of motion (AAROM) if a flexion contracture is present before immobilization, until full ROM is obtained. If possible, obtaining elbow extension measurements preseason and/or preinjury is helpful in planning rehabilitation goals, as the preinjury elbow motion may lack 3–5 degrees of full extension and is more likely to develop flexion contractures. Tightness in the joint capsule, formation of scar tissue in the brachialis and adhesions in the anterior capsule limit the full extension of the elbow and bilateral measurements can differ by as much as 5–6 degrees. In addition to AAROM, grade I and II mobilizations may assist in improving ROM. Specifically, when end range of elbow extension is difficult to obtain, humeroulnar posterior glide oscillations and low-load long duration stretch can be helpful. The intensity of mobilizations and stretching is dependent on the healing of the tissues and the report of pain during limited motion. If there is pain before application of resistance, gentle and graded stretching supports the healing structures in the safest manner.

The second phase of rehabilitation should include isometric elbow strengthening along with continued strengthening of the shoulder and scapula. Rotator cuff muscle strengthening against gravity and the use of exercise bands is added. Isotonic elbow strengthening is included when full AROM is achieved. It is best to begin with concentric and progress to eccentric elbow extension/flexion, wrist extension/flexion, and forearm supination/protonation. Beginning proprioceptive training to limit muscle fatigue may also be initiated in this phase. Graded closed chained exercises are also added to dynamically strengthen the upper extremity stabilizers and core.

The third phase of rehabilitation consists of further dynamic strengthening of the core and upper extremities. Increased strengthening of eccentric elbow flexion is an important focus, as eccentric control limits abutment of the olecranon in the fossa during deceleration and the biceps acts as a stabilizer during follow-through of a throw. Dynamic closed chained exercises, plyometrics, and a throwing program should be completed during this phase of rehabilitation ( Video 1 ). Throughout this process, it is important to keep in mind skeletal maturity, workload limits, and the biomechanics of throwing. The amount of torque at the shoulder and elbow during an overhead throw increases between the ages of 12 and 15, thereby increasing the importance of biomechanical control while throwing to limit the risk of injury, as the skeletal system achieves maturity. A comprehensive list of dynamic exercises that are commonly incorporated into rehabilitation protocols for athletes recovering from little league elbow can be found in Appendix 6 .

Various throwing programs have been created to promote full preinjury recovery given the biomechanical demands unique to each throwing phase. Early and late cocking stages apply significant valgus overload and distraction to the medial elbow. The position of the pelvis, trunk, and ipsilateral one-foot balance during the windup stage impacts the arm speed during acceleration. Peak elbow valgus torque is present just before the acceleration, right before maximum shoulder external rotation. Observation and feedback are necessary to provide the patient with optimal pitching technique as they return to throwing. The “Thrower’s Ten program” and the “Advanced Thrower’s Ten Program” are two common throwing programs for youth athletes to follow, both in-season and for out of season training. ( Appendix 2 ) ( Appendix 3 ). In addition, the University of Delaware and the Mayo Clinic created training programs, the Interval Throw Program, which provides throwing limits based on distance and intensity for little league players based on age. ( Appendixes 7–9 ). Following the completion of a throwing program without return of pain or symptoms, the athlete is advised to complete an interval sports program as it is much more comprehensive and focuses on the use of the extremity and its demands relevant to different sports.

Anatomy and Classification

OCD of the elbow is commonly observed on the distal anterolateral aspect of the humerus due to the poorly vascularized capitellum. OCD of the capitellum affects the subchondral bone as well as the overlying cartilage of the central or lateral aspect of the capitellum. OCD is differentiated from Panner’s disease, which is an osteochondrosis of the entire capitellum and occurs in younger patients, 5–10 years old. Panner’s disease does not present with loose bodies.

Initially when an OCD occurs, the capitellum will demonstrate some subchondral flattening or sclerotic bone with disturbance of the articular cartilage. As the disease progresses, limited blood supply to the area causes the bone and cartilage to separate and form a loose body, which can impact motion, cause pain and lead to a popping/catching sensation with elbow motion.

Clinical Assessment

Patients with OCD classically report pain on the lateral or central aspect of the elbow and may remark about a “catching or popping” due to a loose body. Less than 20% of patients present with edema over the affected region. Radiocapitellar tenderness to palpation may be present, along with decreased elbow extension or crepitus. The active radiocapitellar compression test, in which the examiner places the patient’s elbow in full extension and the patient actively pronates and supinates the forearm, can be used to illicit lateral elbow pain in a patient with an OCD. A positive test result reveals either an OCD or medial ulnar collateral ligament weakness and indicates the need for further work-up, typically with advanced imaging such as an MRI.

Given the limited symptomatic presentation before fragmentation, radiographic imaging is a crucial component of the diagnostic work-up. Radiographs positive for an OCD will demonstrate subchondral flattening, sclerotic bone, and/or radiolucency during the early stages ( Fig. 24.6 ). If plain radiographs do not demonstrate an abnormality, an MRI can be obtained to further evaluate for an OCD lesion ( Fig. 24.7 ). In the context of the diagnostic evaluation, assessing the stability of the OCD lesion is imperative, as instability may impact the decision for surgical intervention.

Radiographs of an elbow OCD in a 13-year-old female volleyball player. Note the lucency in the capitellum: (A) AP view, (B) oblique view, and (C) lateral view.

Courtesy of Joshua M. Abzug, MD.

Sagittal slice of an elbow MRI with an OCD lesion of the capitellum (bottom arrow) and a corresponding loose body in the joint space (top arrow).

Courtesy of Joshua M. Abzug, MD.

Prevention

As a result of the multifactorial etiology of OCD of the capitellum, preventive strategies are limited. Due to a possible genetic link, if the patient has a family history of OCD, it may be recommended that they limit the amount of time participating in an overhead-throwing sport or upper extremity weight-bearing sport, such as gymnastics. In general, a pediatric athlete is unaware of the development of the OCD until there are obvious signs of pain or difficulty with ROM. Once a lesion on the subchondral bone of the elbow is identified, compliance to activity modification of limiting axial load on the radiocapitellar joint and rest is imperative. Early detection of an OCD and immediate activity modification with cessation of the sport and rest have been observed to induce spontaneous healing. However, the importance of continued monitoring of the subchondral bone in the wake of recovery is recommended to safeguard against OCD reoccurrence.

Conservative Treatment

The optimal method of nonoperative treatment of OCD of the capitellum is debated and varies across current literature. Current treatments include termination of the aggravating sport, casting, utilizing a hinged elbow brace, and rest. Management is dependent on the stability of the lesion, the cartilage integrity, and the condition of the capitellar physis. Stable lesions can be treated with a hinged elbow brace, activity modification, and rest and typically demonstrate improvement of symptoms within 3–12 weeks. Additional indications for conservative management include an open capitellar physis, less than a 20-degree limitation in elbow extension/flexion, and/or a primarily intact capitellum on radiographs without fragmentation or instability. Current literature supports nonoperative management for stable OCD lesions, particularly in the young athlete.

Patients should be followed with radiographs in 6–8 week increments to ensure consistency between radiograph improvements and verbalized pain symptoms. Despite reports of improvements in pain, radiographs may not always reflect the same improvements in the radiolucency about the lesion. Therefore, initiation of exercises and activities needs to be carefully weighed with images and patient reports, because increased radiocapitellar stress can cause regression in an unprepared elbow. As radiographs demonstrate recalcification and the patient reports anecdotal improvements, gentle ROM is initiated in occupational or physical therapy. Although patients may be anxious to return to their sport, the patient and family should be counseled to avoid overhead and extended elbow activity to allow the articular surface of the capitellumto fully heal. In the case of failed conservative treatment, surgical intervention may be required.

Operative Intervention

Once operative intervention is determined to be necessary, the specific procedure performed will be dictated by the location and size of the OCD lesion, as well as the presence/absence of a stable cartilage cap or loose bodies. For example, lateral uncontained lesions may be preferably treated with an osteochondral autograft transfer (OATS) procedure, while contained lesions located centrally on the capitellum may be optimally treated with microfracture.

When loose bodies are present, arthroscopic removal or fragment fixation may be attempted. When unstable OCD lesions are observed, in situ fixation may be the ideal intervention. This can be performed using bone pins, Kirschner wires, absorbable pins, Herbert screw fixation, or other implants, such as darts, designed specifically to stabilize OCD lesions.

When full excision of the OCD lesion is not necessary, the surgeon may elect to proceed with a microfracture procedure. Following the removal of any fraying cartilage, a microfracture pick is used to place a number of small holes in the subchondral bone to stimulate bleeding and an inflammatory response with the goal of new cartilage formation. Cartilage restoration using osteochondral autograft transfer (OATS), is indicated for large, unstable lesions, and those covering most the articular surface. These procedures involve the harvesting of bone and intact articular cartilage, typically from the knee in an area with less weight-bearing. The osteochondral plugs are then grafted at the site of the OCD lesion.

Rehabilitation

Depending on the surgical procedure performed, the severity of the injury, and complications, postoperative care will vary. Control of pain and edema are in the forefront of rehabilitation and patients are reminded to avoid aggravating activities, such as prematurely returning to sports and radiocapitellar stress by avoiding full elbow extension on the affected upper extremity. General guidelines for rehabilitation following arthroscopic debridement, microfracture ( Table 24.3 ), and alternative operative procedures warrant 3–5 months for full return to sport ( Table 24.4 ).

Table 24.3

General Rehabilitation Protocol Following Microfracture or Arthroscopic Debridement of OCD of the Capitellum.

Weeks Post-Op	Focus of Rehab
Week 1	• Transition from postoperative dressing to hinged elbow brace and initiate gentle active range of motion under the guidance of an occupational or physical therapist • Edema management • Scar management
Week 4	• Following physician clearance, initiate active assistive range of motion if full range of motion not achieved
Week 6	• Following physician clearance, initiate passive range of motion if full range of motion is not achieved
Weeks 8–12	• Wean from hinged brace when no pain or complications with motion • Begin light strengthening when no pain and full range of motion is achieved
Weeks 10–12	• Dynamic stability and strengthening to entire affected upper extremity • Throwing program
Months 3–4	• Full return to sport

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