Osteochondritis Dissecans of the Elbow
Diagnosis, Treatment, and Prevention
Trevor L. Hall, MD; Anthony M. Galea, MD
THE PHYSICIAN AND SPORTSMEDICINE - VOL 27 - NO. 2 - FEBRUARY 1999
In Brief: Osteochondritis dissecans (OCD) is an inflammation of the bone and cartilage that usually affects adolescents and young adults. A 16-year-old baseball player who had chronic elbow pain illustrates the typical course of OCD of the elbow. Radiographs may be diagnostic, but bone scan is a more sensitive diagnostic tool, and magnetic resonance imaging offers information for staging and characterization of lesions. If symptoms do not resolve with rest, surgery is recommended, including loose-body removal with curettage or drilling. The prognosis is good with early diagnosis and treatment. Left untreated, OCD may progress to degenerative joint disease. Prevention includes strengthening and stretching exercises and limits on throwing activities.
Overuse injuries of the elbow are common in throwing sports such as baseball. An uncommon but important example of these is osteochondritis dissecans (OCD) of the elbow, "a localized injury or condition affecting an articular surface that involves separation of a segment of cartilage and subchondral bone" (1). The area of the elbow most frequently affected is the anterolateral surface of the humeral capitellum (2-4). The following case provides a springboard for discussion of the clinical aspects and management of OCD of the elbow, which, if left untreated, can lead to long-term disability.
A 16-year-old male right-handed pitcher, who had played 5 years of competitive baseball, presented with a 2-year history of right elbow pain. He had been treated with activity modification, physical therapy, and throwing technique analysis, but had continued to pitch in spite of pain. During the second year of his symptoms, the pain worsened, his pitching performance declined, and he began having episodes of locking, which prompted him to seek an assessment.
Physical examination revealed a loss of 10° of extension and flexion limited to 100° (normal, 140° to 150°). The ulnar collateral ligament showed mild laxity with a good end point, and there was tenderness at the radiocapitellar joint and at the medial epicondyle.
Plain radiographs (figure 1) showed multiple loose bodies in the anterior ulnar region of the elbow joint compartment, as well as ossification within the medial epicondylar bursa. Magnetic resonance imaging (figure 2) demonstrated several abnormalities, including a 5-mm depression on the anterior aspect of the capitellum, osteochondral fragments, and a small joint effusion and degenerative changes within the coronoid process and the anterior aspect of the trochlea.
A diagnosis of OCD of the elbow was made, and the patient was referred to an orthopedic surgeon. Arthroscopy was suggested, but the patient decided to quit playing baseball rather than undergo surgery. Eighteen months after presentation, the patient reported that he was pain-free with activities of daily living, but that he had symptoms when he threw a ball hard. Since he was satisfied with his level of activity, he declined further follow-up.
Elbow pain in young throwers is commonly known as Little League elbow, which can involve injury to both the medial and lateral sides of the joint. Injury of the medial side is more common and usually consists of distortion or avulsion of the medial epicondylar apophysis. Damage on the lateral side often consists of OCD of the capitellum, which is much less common than medial injury, but can have rare, severe, long-term consequences.
The incidence and prevalence of OCD of the elbow have not been determined, but it appears to be a rare disorder (1,5,6). Adolescents and young adults are most commonly affected (2,4,7-9), and most cases occur in males, reflecting the greater number of male throwing athletes. The onset of symptoms usually occurs between the ages of 9 and 15 (4,7), although diagnosis may occur years later. Brown et al (7) reported an average interval of 1 year between symptom onset and initial presentation, but in one case series (10) it was found that the average duration of symptoms before diagnosis was 3 to 4 years, and the mean age at diagnosis varied from 17 to 20 (7,10). In two case series (8,9), the mean duration of symptoms prior to surgery was 1 to 2 years.
OCD is more common in athletes who participate in throwing sports such as baseball (2,4,7-10), particularly pitchers (see "Causes of OCD of the Elbow and Related Disorders," below). However, OCD can also affect athletes in wrestling, football, tennis, gymnastics, shooting, shot put, and golf (9-11).
Though OCD usually affects the dominant arm, it can also involve the nondominant arm or be bilateral (4,12). Some authors have also reported (2,4) that OCD tends to occur in families, suggesting a possible constitutional predisposition and/or multifactorial etiology.
Nearly 90% of patients present with a history of elbow pain, and almost 55% report a loss of range of motion (4,7). The onset of symptoms is usually gradual; the pain is usually intermittent and occurs with activity, especially throwing. Other symptoms and signs include clicking, grinding, stiffness, and swelling, while patients with more advanced disease may have loose-body sensations and locking (2-4,7,8). Symptoms typically impair athletic performance as long as the patient participates in the offending activity.
A history of acute injury has been reported (7,8,10) in 14% to 36% of cases, and the diagnosis of osteochondral fracture must always be entertained when acute trauma occurs.
Radiographs. Initial investigations include plain radiographs, which may show findings such as radiolucency or rarefaction of the lateral or central portion of the capitellum. In advanced stages, loose bodies, radial head hypertrophy, and osteophyte formation may be apparent (1,2,7,13).
Unfortunately, radiographs may fail to show the lesion (14). In one case series (8), surgical findings confirmed that only 64% of capitellar OCD lesions and 30% of loose bodies were revealed by plain radiographs, and arthrogram provided no additional information.
Bone scan. Bone scintigraphy will be positive if there is osteoblastic activity or increased vascularity at the site of the OCD lesion. Since a bone scan can detect such minute changes in lesion activity, it provides a sensitive means of identifying OCD lesions (14). Cahill and Berg (12) proposed using bone scan results as part of a staging system for OCD lesions of the knee and suggested its usefulness as a prognostic indicator.
MRI. Magnetic resonance imaging (MRI) is useful for a number of reasons. It can help identify the stage of a lesion, since fragment detachment is indicated on T2-weighted images by the intervening fluid interface. Studies have shown that MRI aids in the detection and staging of OCD lesions of the knee and ankle as well as in the visualization of loose bodies and in monitoring healing (1).
Murphy (15) reported on 11 patients who had elbow pain and swelling; MRI identified 3 who had OCD of the elbow, and all 3 cases were confirmed by operative findings. Ho (16) described the use of MRI in evaluating the integrity of the overlying articular cartilage for potential instability of osteochondral fragments in OCD of the elbow. In addition, MRI can facilitate early treatment because it can reveal radiographically occult osseous changes such as contusions and stress reactions before detachment or fragmentation has occurred.
CT. Computed tomography (CT) provides good osseous architectural detail, but its usefulness in determining the stage of a lesion and assessing fragment separation is limited (14,17). Unlike MRI, CT does not show the fluid interface between the fragment and its bed, and, unlike scintigraphy, CT does not detect activity of an OCD lesion.
The choice of conservative or operative treatment depends on lesion size and site, the presence of loose bodies, and the condition of the articular cartilage of the capitellum and radial head.
Conservative measures. Once an athlete becomes symptomatic, he or she should avoid throwing and other aggravating activities until symptoms subside.
Early OCD lesions in younger patients are thought to respond well to conservative measures (1). Early OCD lesions of the humeral capitellum as well as inflammation of the medial epicondylar apophysis—the most common cause of elbow pain in adolescent throwers—should respond to modified activity (no throwing or physical loading of the painful elbow), nonsteroidal anti-inflammatory medication, icing, and physiotherapy such as forearm flexor and extensor strengthening and stretching (18). Pappas (3) noted that nonsurgical management yields better results in skeletally younger patients (boys who are 13 and younger and girls who are 11 and younger) than in older ones and worse results in patients who have more advanced OCD lesions than those with less advanced ones.
When elbow pain resolves, patients may return to activity gradually, as has been described by Congeni (18), and throwing technique problems should be addressed. Radiologic evidence of healing may be obtained by using MRI and serial bone scintigraphy (1,12).
Surgery. Surgery should be considered if conservative measures fail after a trial of at least 8 to 12 weeks. Of the many surgical options, arthroscopic debridement with curettage and drilling of the OCD lesion bed is one of the most commonly done.
Studies assessing the outcome of surgery have been conducted (table 1), but findings require cautious interpretation for a number of reasons. The studies vary substantially in the subjects' age at diagnosis and treatment and in the mechanism of injury, duration of symptoms before treatment, and years of follow-up. There are also differences in the diagnostic criteria, staging of OCD lesions, indications for surgery, and surgical techniques. All of these may affect outcomes and limit the usefulness of comparisons. Randomized, controlled studies are obviously needed to determine the optimal treatment for this condition.
Since OCD of the elbow is an overuse injury, prevention is the most effective management strategy. Young athletes involved in throwing activities, along with coaches and parents, need to be informed about the vulnerability of the elbow. Teaching them about Little League elbow and the potential seriousness of OCD of the elbow is important for primary prevention (19). Other preventive steps include mandatory pitch counts per game or practice in Little League baseball. Although researchers have not defined the optimal numbers, limiting young pitchers to 90 to 100 pitches per game has been a reasonable suggestion (18). Limiting the number of innings per game and per week (eg, 6 innings per week) as well as the number of practices has also been suggested (5).
Proper technique and conditioning are important preventive measures for baseball players and other at-risk athletes such as javelin throwers. Injury is common when an activity involves a whipping or snapping motion with the arm in a relatively horizontal position during delivery. Baseball pitchers should avoid opening their lead shoulder and lifting their back foot from the ground too soon (20). Strengthening of forearm muscles, including flexors and extensors, should begin before the season starts (18).
Taking such steps can limit wear and tear on young elbows and help young athletes avoid overuse injuries that take them away from the games they love to play. In symptomatic patients, timely diagnosis and treatment can help them limit and recover from the effects of OCD of the elbow.
Causes of OCD of the Elbow and Related Disorders
Elbow pain in young throwers, often called Little League elbow, reflects a range of injuries resulting from stresses on both sides of the joint. Lateral stresses can lead to osteochondritis dissecans of the capitellum, while medial stresses may injure the medial epicondylar apophysis.
Osteochondritis dissecans. The pathophysiology of osteochondritis dissecans (OCD) of the elbow has not been completely explained. However, evidence suggests that it develops in genetically and anatomically susceptible individuals and involves capitellar osteochondral fatigue and fragmentation, most commonly caused by abnormal chronic compressive and shearing forces to the radiocapitellar joint.
In 1959, Haraldsson (1), describing the developmental vascular anatomy of the humeral capitellum, observed that the blood supply predominantly comes from vessels that enter the chondroepiphysis posteriorly. These vessels penetrate the developing osseous nucleus but do not communicate with the metaphysis or supply the capitellar articular surface. Various authors (2) suggest that the consequent tenuousness of blood supply to the capitellum in children results in capitellar ischemia or at least a predisposition to the development of OCD lesions.
The most likely cofactor in the development of OCD of the elbow is repetitive microtrauma to the radiocapitellar joint as a result of chronic overuse (3-6). As described by Tullos and King (7,8), the throwing motion, especially the acceleration and follow-through phases of pitching, imposes a valgus force on the elbow (figure 1: not shown). This results in compressive stress on the radiocapitellar joint. In the follow-through phase, elbow extension and forearm pronation add a shearing force to the compressive stress on the radiocapitellar joint.
According to one theory (2,3,9), these stresses eventually lead to subchondral bone fatigue fracture, which, failing to heal, results in bone resorption and separation of an osteochondral fragment from its underlying bed (figure 2: not shown). Without its osseous structural support and vascular supply, the separated fragment becomes an avascular, partial or complete osteochondral loose body.
In a series of 21 cases of OCD of the elbow, Brown et al (4) noted that most of the patients participated in throwing or racket sports, and he concluded that impingement at the radiocapitellar joint resulted in capitellar surface breakdown and radial head hypertrophy. Schenck et al (10), in a cadaveric study, noted that the capitellar surface was soft relative to the radial head and speculated that this mechanical disparity may predispose to OCD.
Medial compartment injury. Pathologic bony and soft-tissue changes other than OCD may occur in a young baseball player who has elbow pain. While it compresses the lateral structures of the elbow, the throwing motion (figure A: not shown) involves a distraction force to the medial structures, in particular the medial epicondylar origin of the wrist flexor tendons, the medial epicondylar apophysis, and the ulnar collateral ligament (8,11). Inflammation, fragmentation, and even avulsion of the apophysis (figure B: not shown) can occur and most likely account for most cases of Little League elbow (2,12,13). (See "Treating—and Preventing—Little League Elbow," March 1994, page 54, and "Osteochondritis Dissecans In a Young Pitcher: Why Early Recognition Matters," March 1997, page 85.)
Panner's disease. Panner's disease is an osteochondrosis involving rarefaction and fragmentation of the entire capitellar ossific nucleus in children usually between 4 and 8 years old; their prognosis is generally good, as the lesion tends to heal without late sequelae (2,3,14). Whether these changes are similar to osteochondroses such as Legg-Calvé-Perthes disease (2) or are a different stage of OCD is still debated.
Dr Hall is a lecturer in the department of family and community medicine at the University of Toronto and practices at the Sport Centre for Advanced Research and Education at Women's College Hospital in Toronto and at Waterloo Sports Medicine Centre in Waterloo, Canada. Dr Galea is the director of the Institute of Sports Medicine and Human Performance in Toronto and the physician for the Canadian national freestyle ski team. Both are members of the Canadian Academy of Sport Medicine. Address correspondence to Trevor L. Hall, MD, Waterloo Sports Medicine Centre, 65 University Ave E, Suite 5, Waterloo, ON, Canada N2J 2V9.