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Recognizing Upper-Extremity Stress Lesions

Thomas D. Cervoni, MD; Joseph R. Martire, MD; Leigh Ann Curl, MD; Edward G. McFarland, MD

THE PHYSICIAN AND SPORTSMEDICINE - VOL 25 - NO. 8 - AUGUST 97


In Brief: Athletes in sports such as baseball, gymnastics, weight lifting, javelin, and racket sports are susceptible to stress lesions in the bones of the upper extremities. Injuries range from periostitis to bone spurs to stress fractures. Injuries in adolescents typically involve the growth plates, while midshaft injuries at the area of muscle insertion are more common in adults. It's especially important to detect these injuries in adolescents because untreated stress lesions at growth plates can have serious consequences. Plain films demonstrate obvious fractures and physeal injuries, but triple-phase bone scans are often needed to define the extent of stress lesions.

Stress fractures of the upper extremity are relatively rare. Orava et al (1) studied 142 stress fractures in athletes and found 2.8% in the upper extremity. What makes diagnosing this injury a challenge is that it is often young, healthy athletes who present with an upper-extremity stress fracture, and this injury occurs in normal as well as osteopenic bone.

Stress fractures are most commonly encountered in the weight-bearing bones of the lower extremities. In a series of 320 athletes with stress fractures, Matheson et al (2) reported that 49% occurred in the tibia and 25% in the tarsal bones. Similarly, in a study of stress fractures, McBryde (3) reported that 3% of stress fractures occur in the upper extremities. Throwing or racket sports, as well as sports in which the upper extremity bears weight (eg, gymnastics), generate tremendous forces across the bones of the upper extremities and have been associated with recognized sport-specific overuse patterns.

Bone Behavior Under Stress

At normal levels of activity, tissue breakdown and repair are balanced; however, when activity increases and tissue breakdown exceeds normal repair, tissue fails and symptoms develop. Other factors besides activity can contribute to tissue breakdown and inhibit repair; in women these factors include eating disorders and hormone imbalances.

Overuse injury to bone results in stress fractures—propagating microfractures of bone that result from prolonged, repetitive muscle or gravitational overload exceeding the bone's ability to maintain itself according to Wolff's law (whereby the structure of the bone adapts in response to the direction and magnitude of the forces acting on it). The two main types of bony stress fractures are fatigue fractures (abnormal stress on normal bone) and insufficiency fractures (normal stress on abnormal bone). With either type, there is an imbalance between the amount of stress and the bone's remodeling capacity.

In response to injury, the periosteal tissue lining the bones is activated in the acute repair process. This is called periostitis, or inflammation of the lining adjacent to the bony cortex, as evidenced by the widening and separation of the periosteum often seen on plain radiographs. Bone spurs are chronic bony prominences seen in response to normal or abnormal stresses. Bone spurs can appear normally and often do not correlate with symptoms, unlike periostitis. Stress reactions and microfractures within the bone occur when breakdown exceeds repair, and can eventually lead to macroscopic stress fractures.

Though painful, microfractures are initially not evident on radiographs. With repetitive injury and attempted healing, eventually a macroscopic stress fracture can be seen on radiographs. Without treatment, complete structural failure or bicortical fractures can cause prolonged symptoms.

It is important to note that there are normal bony prominences that develop in response to increased stress, most notably the tuberosities throughout the body. Also, there are other diaphyseal areas of focal cortical thickening from normal muscle forces that can be confused with abnormal stress lesions, tumors, or infection. They are called "tug lesions," and a typical example is the deltoid insertion on the humeral shaft (4). If activity and intensity increase, stress fractures can then occur at the bony shaft, at times adjacent to the normal tug lesion.

Adolescents' Injuries

Growing athletes are particularly susceptible to overuse injury at the open growth plates (physes). Stress overload at the physis can impair ossification and can, when prolonged, result in physeal widening that can be appreciated on plain radiographs. Examples of physeal stress lesions include proximal humeral epiphysiolysis (Little League shoulder), medial epicondylar apophysitis (Little League elbow), olecranon physeal stress fracture, and distal radial physeal stress injury (gymnast's wrist).

[FIGURE 1] Humerus. Proximal humeral epiphysiolysis, first called "Little Leaguer's shoulder" by Dotter in 1953, is seen in adolescent throwers usually between ages 12 and 15 (4). This usually occurs in the dominant arm as a result of excessive throwing and is a traction injury of the physeal plate. The hallmark finding is uniform widening of the proximal humeral growth plate (figure 1). Minor fragmentation of the lateral epiphysis is occasionally noted. Periostitis and endosteal callus formation can be seen on the bone scan during healing.

Elbow. In skeletally immature throwing athletes, the medial epicondyle apophysis usually fails before the medial collateral ligament (MCL) does. The chronic pull of the MCL may cause a traction apophysitis or avulse the apophysis of the medial epicondyle. Widening with delayed closure or fragmentation of the epicondyle may be seen. In some cases, the ossification center may remain permanently unfused. Associated spurs in the lateral margin of the trochlea have been described. Increased uptake is seen on the bone scan throughout the apophysis. Chronic lateral compression can lead to local avascular necrosis or osteochondrosis (Panner's disease) of the humeral capitellum (5).

Little League elbow is a common example of elbow stress fractures in young throwing athletes. Seen in adolescent pitchers, it is caused by stress induced in the late cocking and early acceleration phases of the throwing cycle. The movements exert excessive traction on the medial epicondyle apophysis and excessive impaction laterally at the radiocapitellar joint (figure 2) (6,7).

[FIGURE 2] Because of valgus overload and high axial compression, gymnasts may develop osteochondrosis of the humeral capitellum, of which seven cases were described by Singer and Roy (8).

Olecranon physeal stress fractures result from overuse in adolescent baseball and tennis players. Hyperemia of the ossification center and subsequent overgrowth and delayed closure of the growth plate have been described in these athletes. Chronic incongruity between the hypertrophied olecranon and the smaller fossa can lead to pain, loose bodies, and arthritis. Triceps overload and traction olecranon apophysitis have also been reported in javelin throwers (4).

Distal radius. The distal radial epiphyseal plate is the classic location of injury in "gymnast's wrist," though the term has been used to describe a spectrum of various bony and soft tissue injuries (table 1: not shown). Unlike other growth plate overuse syndromes in adolescents, this is a compression injury. Repetitive performance on the pommel horse and uneven bars causes excessive wrist loading. Markolf et al (9) studied these wrist-loading patterns in 17 elite male gymnasts who performed pommel horse exercises and found overall wrist loading rates of 5.2 to 10.6 times body weight. These loads are comparable to heel strike during running.

DiFiore et al (10) analyzed the factors associated with wrist pain in gymnasts and concluded that advanced age, increased training intensity and skill level, and entering the sport at an older age were important determinants in the development of wrist pain in gymnasts. Irregular widening of the physis is noted, as well as flaring of the metaphysis and delayed closure of the growth plate. The distal ulnar physis may also be involved. The diagnosis can be made with a good history and physical supported by plain radiographs. When needed, triple-phase bone scanning (TPBS) will demonstrate increased uptake across the physis.

[FIGURE 3] Skateboarders, in-line skaters, and weight lifters can also present with wrist pain and distal radial stress lesions. Repetitive handstands while skateboarding can lead to severe wrist pain and classic, intense uptake across the physis on TPBS (figure 3). As with skateboarding, many of the maneuvers of the freestyle in-line skater involve axial, shear, and torsional forces on the wrists. A classic case in a 15-year-old male in-line skater has been described by Carter et al (11). Radiographic changes include flattening of the medial radial epiphysis, cysts, sclerosis, physeal widening and irregular changes, and metaphyseal flaring. Similar changes in the wrists as well as Salter-Harris fractures have been described in weight lifters (4).

The Adult Injury Spectrum

While upper-extremity stress fractures in adolescents are more common at growth plates, adult's lesions are more common in the diaphyses of the bone and the periarticular sites. In the diaphysis, common locations are near large-muscle insertions where there is localized stress on the bone. Upper-extremity stress fractures in adults have been reported primarily in the humeral shaft, olecranon process, ulnar shaft, and distal radius.

Humerus. Forceful repeated resistance to abduction of the upper arms places excessive traction stress and strain on the humeral periosteal insertion of the pectoralis major muscle. The injury is common in gymnasts who perform on iron rings and weight lifters who do lateral curls. In gymnasts, this lesion is referred to as "ringman's lesion (12)." The condition is often bilateral, and bone scans demonstrate focal periostitis and associated inflammatory response in the adjacent soft tissues.

[FIGURE 4] Humeral "shin splints" or periostitis is also seen in baseball pitchers, javelin throwers, and tennis players, and stress fractures of the humeral shaft of the dominant arm are also seen in throwers (figure 4). Instances of complete humeral fractures have been described in adult baseball pitchers.

Elbow. The elbow in adult throwing athletes is also susceptible to overuse injury from medial traction and lateral compression (figures 5 and 6). Except for growth plate closure, injuries in adults are similar to those in adolescents. Valgus stress radiographs may show medial joint opening from chronic stretch of the medial collateral ligament.

Ulna. Ulnar shaft stress fractures have been reported after forearm curls in weight lifters and pitchfork use in farmers, and in water polo players, baseball pitchers, tennis players, bowlers, football players, volleyball players, martial arts participants, and wheelchair and crutch users. Meese and Sebastianelli (13) reported two cases of periostitis of the ulnar shaft, one in a bowler and one in a football center. The bowler was playing three games three times a week, and the football center had increased pain when lifting weights and blocking opponents. With modification of activity and treatment, both returned to asymptomatic previous levels of sports activity by 6 weeks. Bell and Hawkins (14) reported a stress fracture of the distal ulna in a competitive tennis player. They concluded that two-handed backhand and topspin forehand strokes increased the load on the distal ulna.

Distal radius. As in adolescents, distal radius stress fractures have been described in adults. Mandelbaum et al (15) studied 38 collegiate gymnasts and discovered that all had significantly greater positive ulnar variance than the controls. This may represent growth disturbance of the distal radius in younger, developing gymnasts that leads to radial shortening and positive ulnar variance when they are collegiate gymnasts. The pommel horse routine was consistently responsible for wrist pain in this group of gymnasts.

The Diagnostic Strategy

The keys to diagnosing a stress fracture of the upper extremity are a thorough patient history, a careful physical examination, and imaging studies as needed.

History. As is typical of all stress lesions, a single traumatic event is rarely elicited in the history. More typical is a change in the patient's activity level that preceded the development of symptoms—initiation of a new or additional sport, or a change in the frequency, duration, or intensity of participation in an established sport. For some patients, a change in equipment or technique may contribute to symptom development.

[FIGURE 5]

The primary symptom in overuse or stress injury is pain only during the offending activity. However, if the injury is long-standing and the extent of injury more significant, pain can persist after activity and may even be present with activities of daily living. In patients who have chronic pain, other conditions such as tumor, infection, or juvenile arthritis must also be considered.

Physical examination. Physical examination early in the clinical course will demonstrate normal muscle mass and range of motion, and focal pain at the injury site. In more severe or chronic cases, there may be localized swelling with erythema or warmth and limited range of motion such as decreased elbow extension with Little League elbow. Usually there is no fever, leukocytosis, or elevated erythrocyte sedimentation rate.

Imaging. In athletes complaining of persistent bone or joint pain, plain film radiographs are always the first imaging test performed. Anteroposterior, lateral, and oblique views are often needed because the findings may be subtle and better seen on certain projections. The hallmark of physeal stress injuries is widening of the growth plate seen on plain radiographs, though in early cases the radiographs will be normal. Comparison views of the contralateral side are often helpful. Later radiographs may demonstrate periosteal reaction and cortical hypertrophy. In advanced cases, linear sclerosis with unicortical disruption may be seen.

If radiographs are negative and the pain persists, then TPBS is suggested because it is well tolerated by patients and highly accurate, and it allows the physician to evaluate large anatomic areas. TPBS is the gold standard in the evaluation and early detection of stress injuries because it allows the radiologist to accurately assess for increased metabolic activity. By using careful diagnostic imaging criteria, stress fractures can be differentiated from periostitis (16). TPBS is also more readily available and less expensive than magnetic resonance imaging (MRI).

MRI is indicated if the bone scan is negative or if problems such as tumor, soft-tissue injury and/or joint injury are suspected.

Managing Stress Lesions

[FIGURE 6] Treatment of physeal injuries or stress fractures consists primarily of rest from the offending sport. Asymptomatic activity and exercise can be permitted. Some athletes can be advised to change their role on the team temporarily, such as switching from pitching to first base. Periostitis usually responds to rest and anti-inflammatory medications. Complete fractures, however, require casting or bracing until the patient is asymptomatic. Ice, stretching, range-of-motion exercises, occasional anti-inflammatory medications, aerobic conditioning, and cross-training can be included in the treatment plan. Return to sports is based on symptoms, not on follow-up bone scans. The TPBS usually demonstrates persistent activity long after the clinical symptoms have resolved. With complete stress fractures, a rest period of 6 weeks or longer is usually required before return to full activity. Fractures that displace or involve a joint may require reduction and internal fixation.

Most injuries heal without any long-term sequelae. However, misdiagnosis or neglect can lead to devastating problems. For example, continued pitching with Little League elbow can lead to avascular necrosis of the capitellum, early arthritis, and joint destruction. Medial collateral ligament instability can also occur. Chronic untreated olecranon physeal stress fractures can cause olecranon hypertrophy, loose bodies, early arthritis, triceps weakness, and elbow stiffness and pain. Chronic compression on a growing physis can lead to partial growth arrest, limb length inequality, and angular deformity. One case of an acquired Madelung's deformity has been described in an athlete with gymnast's wrist (17). Complete bicortical fracture of an untreated stress lesion is unusual in the upper extremity but can occur.

Promising Outcomes

Though generally rare, stress lesions must be included in the differential diagnosis of athletes presenting with upper-extremity pain. With prompt diagnosis and treatment of osseous stress lesions, the prognosis for full recovery and return to sports is excellent.

References

  1. Orava S, Puranen J, Ala-Ketola L: Stress fractures caused by physical exercise. Acta Orthop Scand 1978;49(1):19-27
  2. Matheson GO, Clement DB, McKenzie DC, et al: Stress fractures in athletes: a study of 320 cases. Am J Sports Med 1987;15(1):46-58
  3. McBryde AM Jr: Stress fractures in athletes. J Sports Med 1975;3(5):212-217
  4. Keats TE: Radiology of Musculoskeletal Stress Injury. Chicago, Year Book Medical Publishers, 1990, pp 1-34
  5. Newberg AH: The radiographic evaluation of shoulder and elbow pain in the athlete. Clin Sports Med 1987;6(4):785-809
  6. Jobe FW, Nuber G: Throwing injuries of the elbow. Clin Sports Med 1986;5(4):621-636
  7. Slocum DB: Classification of elbow injuries from baseball pitching. Tex Med 1968;64(3):48-53
  8. Singer KM, Roy SP: Osteochondrosis of the humeral capitellum. Am J Sports Med 1984;12(5):351-360
  9. Markolf KL, Shapiro MS, Mandelbaum BR, et al: Wrist loading patterns during pommel horse exercises. J Biomech 1990;23(10):1001-1011
  10. DiFiore JP, Puffer JC, Mandelbaum BR, et al: Factors associated with wrist pain in the young gymnast. Am J Sports Med 1996;24(1):9-14
  11. Carter SR, Aldridge MJ, Fitzgerald R, et al: Stress changes of the wrist in adolescent gymnasts. Br J Radiol 1988;61(722):109-112
  12. Martire JR, Levinsohn EM: Imaging of Athletic Injuries: A Multimodality Approach. New York City, McGraw-Hill, Inc, 1992, pp 181-279
  13. Meese MA, Sebastianelli WJ: Periostitis of the upper extremity, a report of two cases and literature review. Clin Orthop 1996;Mar(324):222-226
  14. Bell RH, Hawkins RJ: Stress fracture of the distal ulna: a case report. Clin Orthop 1986;Aug(209):169-171
  15. Mandelbaum BR, Bartolozzi AR, Davis CA, et al: Wrist pain syndrome in the gymnast: pathogenetic, diagnostic, and therapeutic considerations. Am J Sports Med 1989;17(3):305-317
  16. Martire JR: The role of nuclear medicine bone scans in evaluating pain in athletic injuries. Clin Sports Med 1987;6(4):713-737
  17. Vender MI, Watson HK: Acquired Madelung-like deformity in a gymnast. J Hand Surg (Am) 1988;13(1):19-21

Dr Cervoni is an orthopedic sports medicine fellow at Johns Hopkins University in Baltimore. Dr Martire is director of nuclear medicine at The Union Memorial Hospital in Baltimore, an assistant professor of radiology at Johns Hopkins University, and an editorial board member of The Physician and Sportsmedicine. Dr Curl is assistant director and Dr McFarland is director of the section of sports medicine and shoulder surgery in the Department of Orthopaedic Surgery at Johns Hopkins University. Address correspondence to Edward G. McFarland, MD, Johns Hopkins University, Section of Sports Medicine and Shoulder Surgery, Dept of Orthopaedic Surgery, 2360 W Joppa Rd, Suite 205, Lutherville, MD 21093.


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