Nonunion of the olecranon epiphysis treated with sliding bone graft and tension band wire. A case report

Classification of Olecranon Stress Fractures in Baseball Players

BACKGROUND

Although the onset mechanism of an olecranon stress fracture (OSF) due to a throwing disorder is believed to involve valgus extension overload, olecranon posteromedial impingement, or triceps traction force, this issue is still debated in the literature.

PURPOSE

To establish a classification system for the different types of OSFs to improve diagnosis and clarify the onset mechanism.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 200 baseball players (198 male, 2 female; mean age, 16.1 years; age range, 13-27 years) who were diagnosed with an OSF from January 1987 to July 2012 were studied. Combined disorders as well as the direction and form of the fracture line were analyzed on plain radiographs, computed tomography, and magnetic resonance imaging. Furthermore, the presence or absence of ulnar collateral ligament (UCL) injuries and avulsion fractures of the lower pole of the medial epicondyle was determined by imaging findings to calculate the combined percentage of OSFs. In addition, the prevalence of OSFs was evaluated among patients who were evaluated between April 2008 and March 2011 for throwing elbow disorders.

RESULTS

There were 5 types of OSFs identified in the new classification system: physeal, classic, transitional, sclerotic, and distal. The physeal type was further separated into stages 1 to 4 based on severity. The mean age for each type identified was as follows: physeal, 14.1 years; classic, 18.6 years; transitional, 16.9 years; sclerotic, 18.0 years; and distal, 19.6 years. A concomitant UCL injury and/or medial epicondyle avulsion fracture was diagnosed in 71% to 95% of cases, depending on the OSF type. Among baseball-related elbow disorders, the incidence of OSFs was 5.4%.

CONCLUSION

This study presents a new classification system for the different types of OSFs based on the origin and direction of the fracture plane. This new system was strongly influenced by the age at symptom onset. Such information is essential for successful open reduction and internal fixation by ensuring that fixation pressure is perpendicular to the fracture plane, which will avoid the recurrence of stress fractures. In addition, the prevalence of UCL injuries suggests that it is a major risk factor for the development of OSFs.

Valgus extension overload syndrome and stress injury of the olecranon

Basic science studies have improved our understanding of the pathomechanics for valgus extension overload and olecranon stress fractures. These disorders result from repetitive abutment of the olecranon into the olecranon fossa combined with valgus torques, resulting in impaction and shear along the posteromedial olecranon. The patient history and physical examination are similar for each disorder. Imaging studies including plain radiographs, computed tomography, MRI or bone scan may be necessary for accurate diagnosis. Clinical and basic science support mandatory and careful assessment of the medial collateral ligament when valgus extension overload is identified and limited debridement of the olecranon when surgery is indicated. For stress fractures that fail nonoperative management, treatment with internal fixation provides good results.

Return to sport following elbow surgery

Although less common than injuries to the knee or shoulder, elbow injuries can be a substantial challenge to sports medicine providers. Many elbow problems respond to routine nonoperative measures including periods of activity modification and physical therapy, but others may ultimately require surgery. Following surgery, appropriate attention to rehabilitation is important to achieve optimal function. This article addresses some of the more common sports-related operative elbow pathology, basic principals of surgery (with an emphasis on techniques only where it may impact rehabilitation or return-to-sport decisions), and return-to-play decisions (including typical "targeted" time frames). The emphasis is on an understanding of sport-specific functional demands and the difficult assessment of reinjury risk following surgery.