Age-Specific Prevalence and Clinical Characteristics of Humeral Medial Epicondyle Apophysitis and Osteochondritis Dissecans: Ultrasonographic Assessment of 4249 Players

Abstract

Background: Traction apophysitis of medial epicondyle (MEC) lesions and osteochondritis dissecans (OCD) of the capitellum are common elbow injuries in adolescent baseball players. However, the age-specific prevalence of these pathologies and their influence on elbow pain remain unknown.

Purpose: To investigate the age-specific prevalence of each MEC lesion and capitellar OCD and to identify the incidence of elbow pain in each condition.

Study design: Descriptive epidemiology study.

Methods: Study participants consisted of 4249 baseball players aged 6 to 17 years. A questionnaire was used to assess history of elbow pain, and morphological changes of the elbow joint were assessed using ultrasonography.

Results: Regarding MEC lesions, fragmented (FG) and irregular (IR) lesions both reached their greatest respective prevalence at 11 to 12 years of age. After 14 years of age, IR decreased sharply, whereas FG was maintained at approximately 10%. Hypertrophic (HT) lesions increased sharply, reaching over 50% at 16 years of age, while there was a decrease in IR and FG lesions in the same age group. The prevalence of capitellar OCD remained the same (approximately 2%) throughout all ages except for in players aged 7 to 8 years (>7%). Players with MEC lesions had significantly greater prevalence of a history of elbow pain compared with those without (68.0% vs 39.1%) and were at a significantly greater risk for FG lesions (odds ratio [OR], 4.04; 95% CI, 3.16-5.22) compared with IR (OR, 3.22; 95% CI, 2.44-4.27) and HT lesions (OR, 2.03; 95% CI, 1.75-2.36). Players with capitellar OCD also had a significantly greater risk of a history of elbow pain (OR, 2.34; 95% CI, 1.40-4.11).

Conclusion: Controlling the amount of practice and its intensity according to the condition of each player in the preadolescent and adolescent periods may be important in accelerating bony healing and decreasing preventable elbow pain in adulthood.

Keywords: age-specific prevalence; elbow pain; medial epicondylar apophysitis; osteochondritis dissecans.

Figure 1.

Ultrasonographic examination of the medial elbow. The elbow was flexed 90° and the forearm was placed in the supinated position. (A) A linear transducer was placed on the medial aspect of the elbow to obtain an image that included (B) the top of the medial epicondyle (MEC) (*), the anterior bundle of the medial ulnar collateral ligament (MUCL), and the sublime tubercle. (C) The MUCL (arrow) was identified as a band-like structure that attached to the MEC and sublime tubercle.

Figure 2.

Medial epicondyle (MEC) lesion diagnostic criteria. The morphology of the anteroinferior aspect of the MEC, where the medial ulnar collateral ligament is attached, was classified into 4 types: (A) normal, (B) irregular, (C) fragmentated, and (D) hypertrophic.

Figure 3.

Ultrasonographic examination of the humeral capitellum. The transducer was first placed on (A) the anterolateral aspect of the elbow in the maximally extended position and then moved to (B) the posterolateral aspect of the elbow in the maximally flexed position. *Humeral capitellum.

Figure 4.

Diagnostic criteria of capitellar osteochondritis dissecans (OCD). (A) No OCD: the subchondral bone is smooth in the normal capitellum. (B) Capitellar OCD was diagnosed by irregularity or fragmentation of the subchondral bone of the capitellum (arrowhead).

Figure 5.

History of elbow pain started to increase at 8 years of age and dramatically rose beginning at 9 years, reaching approximately 50% by the end of 12 years. Seventy percent of players reported a history of elbow pain at the end of high school (age 17 years).

Figure 6.

Prevalence of each type of medial epicondyle (MEC) lesion by age. The prevalence of fragmented (FG) and irregular (IR) lesions reached a peak at 11 to 12 years of age. After 14 years of age, IR lesions decreased dramatically whereas FG were maintained at approximately 10%. The prevalence of hypertrophic (HT) lesions increased sharply to 50% at 16 years of age, whereas IR and FG decreased during that time. N, normal.

Figure 7.

Prevalence of capitellar osteochondritis dissecans (OCD) by age. The prevalence remained at almost the same level at all ages, except for between the ages of 7 and 8 years, where it rose to more than 7%.