Cannulated screw fixation of refractory olecranon stress fractures with and without associated injuries allows a return to baseball

Elbow injuries in overhead throwing athletes: clinical evaluation, treatment, and osteopathic considerations

Injury to the elbow is very common in the throwing athlete and can potentially lead to long absences from play and, in the most severe scenarios, medical retirement. The throwing motion is a highly complex series of movements through the entire kinetic chain that results in very high angular velocities and valgus forces at the elbow joint. The repetitive nature of overhead throwing in combination with the high levels of accumulated force at the elbow puts both pediatric and adult athletes at risk of both acute and chronic overuse injuries of the elbow. This review provides an update on common injuries in the throwing athlete and covers clinical presentation, diagnosis, and treatment of these injuries.

Non-Medial Ulnar Collateral Ligament Elbow Pathology in the Thrower: Valgus Extension Overload, Osteochondritis Dissecans, Olecranon Stress Fracture, and Ulnar Nerve

Injury rates in baseball players reach as high as 5.8 per 1000 at the professional level. Recent data have singled out the elbow as the leading cause of injured list necessitating injuries and the costliest injury location in professional baseball. While the medial ulnar collateral ligament (MUCL) has gained the largest notoriety in this population, elbow injury in the thrower occurs as a spectrum of pathologies. These pathologies may encompass other injuries often resulting from or occurring in conjunction with MUCL insufficiency. These conditions include valgus extension overload syndrome, osteochondritis dissecans, olecranon stress fractures, and ulnar nerve pathology.

Postoperative Imaging in the Throwing Athlete

Overhead throwing subjects the shoulder and elbow to substantial stresses, resulting in unique injury patterns that need to be recognized to allow appropriate treatment and return to sport. At the elbow, the ulnar collateral ligament (UCL) is the primary static restraint to valgus stress and the most commonly injured structure. UCL reconstruction is the most frequent surgical procedure in throwers and may be performed along with ulnar nerve transposition and flexor-pronator mass procedures. Posteromedial impingement and valgus extension overload syndrome are related entities that result in intra-articular pathology, such as osteophytes or bodies lodged within the olecranon fossa, also warranting excision at the time of UCL reconstruction. Shoulder injuries involve the rotator cuff (partial-thickness articular-sided tear), labrum (superior anteroposterior labral tear), and capsule (glenohumeral internal rotation deficit). Surgical options such as cuff repair, labral debridement or repair, and capsular release or tightening therefore target these structures.

Osseous Stress Injuries: Treatment Algorithms and Return to Play

Osseous stress injuries are common in athletes. Specifically, lower extremity injuries are prevalent in running athletes and upper extremity injuries are prevalent in throwing athletes. Such injuries are suspected when there is focal bone tenderness and increased pain with the inciting activity. In elite athletes, osseous stress injuries are a relatively common culprit in lost play time. Thus rapid diagnosis and treatment is imperative to expedite return to play (RTP). The radiologist's role in these cases is not only for diagnosis, but also to grade the injury, which has implications in determining a treatment regimen. The high sensitivity and specificity of magnetic resonance imaging is thus the preferred imaging modality. This article discusses common osseous stress injuries, the imaging findings, and how different treatment regimens affect RTP.

Retrograde headless compression screw fixation of olecranon stress fractures in throwing athletes: a novel technique

Background

An olecranon stress fracture (OSF) is a rare injury most commonly seen in high-level overhead throwing athletes with no clear consensus on surgical treatment. The most common surgical treatment described in the literature is cannulated screw fixation but there have been high rates of reported hardware irritation and need for subsequent hardware removal.

Hypothesis/Purpose

This study describes a novel surgical technique in the treatment of OSFs in high-level throwing athletes using retrograde headless compression screws. We hypothesized that patients would have excellent outcomes and decreased rates of hardware irritation postoperatively.

Methods

A retrospective review of competitive-level throwing athletes who sustained OSFs that were treated operatively using a novel technique using retrograde cannulated headless compression screws to avoid disruption of the triceps tendon. Postoperative outcome measures obtained included the Disabilities of the Arm, Shoulder and Hand score, Mayo Elbow Performance Score, Simple Elbow Test score, Single Assessment Numerical Evaluation score, Visual Analog Scale, arch of motion, and time to return to sport as well as level returned to. Radiographs were obtained routinely at 2-week, 6-week, 12-week, 6-month, 1-year, and 2-year follow-up.

Results

Five of 5 patients who met inclusion criteria were available for final follow-up. Mean age at time of surgery was 20 years (range 17-24). Mean follow-up was 17 months (range 4-33). All patients were baseball players, 4 of which were pitchers and 1 position player. All patients were able to return to sport at the same level or higher at a mean of 5.8 months (range 3-8). Postoperatively, mean arch of motion was 138°, Visual Analog Scale score was 0, Single Assessment Numerical Evaluation score was 90, Disabilities of the Arm, Shoulder and Hand score was 2.0, Mayo Elbow Performance Score was 100, and Simple Elbow Test score was 12. There was no incidence of hardware removal.

Conclusion

This study presents a novel surgical technique in the treatment of OSFs in high-level throwing athletes. The results presented demonstrate that this technique is safe and effective for getting athletes back to play quickly without any complications of hardware irritation which has previously shown to be a significant problem in prior literature.

Elbow Arthroscopy for Posteromedial Impingement and Fixation of Olecranon Stress Fracture

Posteromedial elbow impingement due to valgus extension overload often develops as a result of excessive valgus and extension force during repetitive overhead throwing activities. Impingement classically occurs in throwing athletes such as baseball, tennis, softball, or lacrosse players. If isolated, arthroscopic removal of the posteromedial olecranon osteophytes shows excellent postoperative satisfaction, return to sport rates, and return to previous level of activity. This Technical Note describes treatment of posteromedial elbow impingement syndrome and associated olecranon stress fracture treated with arthroscopic removal of posteromedial osteophytes and arthroscopic-assisted screw fixation.

Evaluation and management of elbow injuries in the adolescent overhead athlete

With an increased interest in youth sports, the burden of overhead throwing elbow injuries accompanying early single-sport focus has steadily risen. During the overhead throwing motion, valgus torque can reach and surpass Newton meters (N m) during the late cocking and early acceleration phases, which exceeds the tensile strength (22.7–33 N m) of the ulnar collateral ligament. While the ulnar collateral ligament serves as the primary valgus stabilizer between and degrees of elbow flexion, other structures about the elbow must contribute to stability during throwing. Depending on an athlete’s stage of skeletal maturity, certain patterns of injury are observed with mechanical failures resulting from increased medial laxity, lateral-sided compression, and posterior extension shearing forces. Together, these injury patterns represent a wide range of conditions that arise from valgus extension overload. The purpose of this article is to review common pathologies observed in the adolescent overhead throwing athlete in the context of functional anatomy, osseous development, and throwing mechanics. Operative and non-operative management and their associated outcomes will be discussed for these injuries.

A Review of Workload-Monitoring Considerations for Baseball Pitchers

Because of the unique demands of a pitch, baseball players have the greatest percentage of injuries resulting in surgery among high school athletes, with a majority of these injuries affecting the shoulder and elbow due to overuse from throwing. These injuries are believed to occur because of repeated microtrauma to soft tissues caused by the repetitive mechanical strain of throwing. Researchers and practitioners have suggested that baseball pitchers' workloads are a significant risk factor for injury in adolescent players, resulting in lost time and slowing of performance development. The purpose of our review was to investigate the current research relative to monitoring workload in baseball throwers and discuss techniques for managing and regulating cumulative stress on the arm, with a focus on preventing injury and optimizing performance in adolescent baseball pitchers.

Elbow Fractures

The elbow joint consists of the humeroulnar, humeroradial, and proximal radioulnar joints. Elbow stability is maintained by a combination of static and dynamic constraints. Elbow fractures are challenging to treat because the articular surfaces must be restored perfectly and associated soft tissue injuries must be recognized and appropriately managed. Most elbow fractures are best treated operatively with restoration of normal bony anatomy and rigid internal fixation and repair and/or reconstruction of the collateral ligaments. Advanced imaging, improved understanding of the complex anatomy of the elbow joint, and improved fixation techniques have contributed to improved elbow fracture outcomes.

Injuries and Conditions Affecting the Elbow Flexor/Pronator Tendons

Common flexor-pronator tendon injuries and medial epicondylitis can be successfully treated nonoperatively in most cases. Operative treatment is reserved for patients with continued symptoms despite adequate nonoperative treatment or in high-level athletes with complete rupture of the common flexor-pronator tendon. The physical examination and workup of patients with flexor-pronator tendon injuries should focus on related or concomitant pathologies of the medial elbow. The gold standard for surgical treatment of flexor-pronator tendon ruptures or medial epicondylitis includes tendon debridement and reattachment.

Olecranon Stress Fracture

Olecranon stress fractures are a rare upper extremity fracture that primarily affects throwing athletes. The incidence of olecranon stress fractures are increasing owing to the number of patients playing and the volume of engagement in competitive sports, especially in the pediatric population. However, olecranon stress fractures can present a challenge from a management and a rehabilitation perspective owing to their vague presentation, thereby affecting how these patients are diagnosed and managed. Therefore, it is imperative to further evaluate the disease process, diagnosis, and treatment of this condition to best manage our patients.

Imaging of the post-operative medial elbow in the overhead thrower: common and abnormal findings after ulnar collateral ligament reconstruction and ulnar nerve transposition

Ulnar collateral ligament (UCL) reconstruction is now being performed more commonly and on younger patients than in prior decades. As a result, radiologists will increasingly be asked to evaluate elbow imaging of patients presenting with pain who have had UCL reconstruction. It is essential for radiologists to understand the normal and abnormal imaging appearances after UCL reconstruction and ulnar nerve transposition, which is also commonly performed in overhead-throwing athletes. Doing so will allow radiologists to provide accurate interpretations that appropriately guide patient management.

Performance and Return to Sport After Open Reduction and Internal Fixation of the Olecranon in Professional Baseball Players

BACKGROUND

The results of open reduction and internal fixation (ORIF) of stress reactions and fractures of the olecranon among professional baseball players with regard to return to sport (RTS) are unknown.

PURPOSE/HYPOTHESIS

To determine the RTS rate and performance of professional baseball players after ORIF of acute, displaced olecranon fractures and olecranon stress fractures and to compare the RTS rate and performance with that of matched controls. The authors hypothesized that there is a high rate of RTS among professional baseball players after ORIF of acute, displaced olecranon fractures and olecranon stress fractures with no significant difference in rate of RTS or performance between cases and controls.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

All professional baseball players who underwent ORIF of the olecranon between 2010 and 2016 were included. Demographic and performance data (before and after surgery) for each player were recorded. Performance metrics were then compared between cases and a group of matched controls.

RESULTS

Overall, 52 professional baseball players (mean ± SD age, 22.6 ± 3.6 years) underwent ORIF of an olecranon fracture. The majority of players sustained a primary olecranon stress fracture (73%) that was fixed with 1 screw (60%), with an overall RTS rate of 67.5%. No difference in RTS rate existed between matched controls and the cases. No significant difference existed between the primary pre- and postoperative performance metrics (ie, change in performance) for pitchers who underwent ORIF of an acute, displaced olecranon fracture or ORIF of a primary olecranon stress fracture. No significant difference existed between pitchers who underwent ORIF of a primary olecranon stress fracture and matched controls in any of the primary performance metrics. Three cases and 2 controls underwent ulnar collateral ligament reconstruction later in their careers after olecranon ORIF.

CONCLUSION

Professional baseball players who undergo ORIF of an olecranon fracture (acute, displaced, or stress) have an RTS rate of 67.5% (57.6% to the same or higher level), which is no different from natural attrition among matched controls. No decline in performance metrics was seen among players who were able to RTS when compared with their preoperative performance or the performance of matched controls.

Approach to Medial Elbow Pain in the Throwing Athlete

PURPOSE OF REVIEW

Injury to the ulnar collateral ligament is the most common, significant injury affecting the medial elbow of the overhead athlete. However, there are many other significant sources of pathology that should be considered. This review seeks to present a broad range of conditions that providers should consider when evaluating the overhead athlete with medial elbow pain.

RECENT FINDINGS

Recent biomechanical studies have deepened understanding of the anatomy and function of the anterior bundle of the ulnar collateral ligament germane to the overhead athlete. Orthobiologics hold potential for expanding the role of non-operative treatment for ulnar collateral ligament injuries. In addition to injury to the ulnar collateral ligament, providers should be prepared to diagnose and treat valgus extension overload, proximal olecranon stress fracture, ulnar nerve pathology, common flexor - pronator mass injury, and, in adolescents, medial epicondylar avulsion, when managing medial elbow pain in the overhead athlete.

Shoulder and Elbow Fractures in Athletes

PURPOSE OF REVIEW

The purposes of this review are to discuss the management of shoulder and elbow fractures in athletes to optimize the return to sport and to highlight treatment impact on the return to play.

RECENT FINDINGS

Fractures of the shoulder and elbow can have profound implications in an athlete career. Recent technique of fractures management trended toward to preserve soft tissue which is critical for an early recovery in athletic population. Arthroscopy presents a strong interest for the treatment of intra-articular fracture, and minimally invasive approach as developed in humeral shaft fracture can be considered to avoid soft tissue damage. Non-articular, stable, and minimally displaced fractures are mainly treated conservatively. However, we encourage a more aggressive approach in shoulder and elbow injuries in the athletes including minimally invasive and stable fixation to preserve vascularity and muscle environment.

Olecranon Apophyseal Nonunion in Adolescent Judo Players: A Report of Two Cases

Olecranon apophyseal nonunion is an elbow injury from overuse that affects adolescent athletes such as baseball pitchers who participate in overhead throwing sports. However, such injury is rare in collision sports. Here, we report two patients with this condition who are Judo athletes. The purpose of this report was to describe three elbows with olecranon apophyseal nonunion in two adolescent patients participating in Judo. This is a case series; the level of evidence is 4. Two 15-year-old patients were evaluated. One suffered from unilateral and the other from bilateral chronic posterior elbow pain. They were diagnosed with olecranon apophyseal nonunion, which was treated using internal fixation and bone grafting. Radiographic evidence of the apophyseal union was observed four months postsurgery. Two elbows were treated with tension band wiring, then they underwent hardware removal six months postsurgery. Both patients returned to their previous levels of activities six months postsurgery. Internal fixation using autologous bone grafting was a useful treatment for these Judo athletes with olecranon apophyseal nonunion.

Elbow Surgery in Athletes

Injuries and disorders of the elbow in athletes are common especially among throwing athletes. Common injuries encountered in the throwing athlete include ulnar collateral ligament injuries, ulnar neuritis, capitellar osteochondritis dissecans, valgus extension overload with posterior olecranon impingement, olecranon stress fracture, and loose bodies. A thorough knowledge of both the functional anatomy as well as throwing biomechanics are required to properly diagnosis and treat these problems. Nonoperative and surgical techniques have continued to advance over the last 25 years allowing for improved prognosis and return to play for athletes affected with elbow pathology.

Stress Fractures of the Elbow in the Throwing Athlete: A Systematic Review

Background:

Stress fractures of the elbow are rare in throwing athletes and present a challenge from both a management and rehabilitation perspective. Although the incidence of stress fractures of the elbow is increasing, there is a lack of data in the literature focused on throwers.

Purpose:

To evaluate studies regarding the management and outcomes of stress fractures of the elbow in throwing athletes.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was conducted by searching the Scopus, PubMed, and Cochrane Library electronic databases to identify studies reporting on the management and outcomes of stress fractures in overhead-throwing athletes. Management data included nonoperative and operative modalities, and outcome data included return to play, encompassing the timing and level of activity. Studies were excluded if the stress fracture of the elbow was not a result of a sport injury attributed to throwing or if the study failed to report whether an athlete returned to play.

Results:

Fourteen studies met the inclusion criteria and were included in this analysis. There were 52 patients in total (50 male, 2 female) with a mean age of 19.7 years (range, 13-29.1 years). The olecranon was the most common location of the stress fracture (51 patients; 98.1%), followed by the distal humerus (1 patient; 1.9%). The majority of patients (n = 40; 76.9%) were treated operatively. Of the 40 patients who were treated surgically, 14 (35.0%) underwent a period of conservative treatment preoperatively that ultimately failed because of persistent nonunion or continued elbow pain. A total of 50 patients (96.2%) returned to sport either at or above their preinjury level. Of the 2 patients (3.8%) who did not return to sport, 1 did not return because of continued elbow pain postoperatively, and the other was lost to follow-up. Complications occurred in 9 patients (17.3%), all of whom were treated surgically.

Conclusion:

On the basis of this systematic review, the majority of elbow stress fractures were treated operatively and approximately one-third after a period of failed nonoperative management. The return-to-sport rate was high. Further, higher level studies are needed to optimize management and return-to-sport rates in this population.

Elbow Injuries in the Adolescent Thrower

PURPOSE OF REVIEW

With an increasing rate of adolescent elbow injuries, especially in throwing athletes, the purpose of this review is to investigate the current literature regarding the diagnosis, treatment, and non-operative and operative outcomes of medial epicondyle fractures, ulnar collateral ligament repair, osteochondritis dissecans of the elbow, and olecranon stress fractures.

RECENT FINDINGS

Acceptable outcomes with both non-operative and operative treatments of medial epicondyle fractures have been reported, with surgical indications continuing to evolve. Unstable osteochondritis dissecans lesions, especially in patients with closed growth plates, require operative fixation, and emerging open and arthroscopic techniques including lesion debridement, marrow stimulation, autograft transfer, and allograft transplantation are described with good outcomes. Ulnar collateral repair has emerged as an exciting treatment option for an avulsion of either end of the ligament in young throwing athletes, with faster rehabilitation times than traditional ulnar collateral ligament reconstruction. Olecranon stress fractures are increasing in prevalence, and when a non-operative treatment course is unsuccessful, athletes have a high return-to-play rate after percutaneous cannulated screw placement. With proper indications, non-operative and operative treatment modalities are reported with a high return-to-play and acceptable clinical outcomes for common elbow injuries, including medial epicondyle fractures, ulnar collateral ligament repair, osteochondritis dissecans of the elbow, and olecranon stress fractures, in adolescent throwing athletes. Further research is needed to better define treatment algorithms, surgical indications, and outcomes.

Olecranon physeal nonunion in the adolescent athlete: identification of two patterns

BACKGROUND

This study aimed to present the outcomes of patients undergoing surgical management of persistent, symptomatic olecranon physes.

METHODS

Consecutive patients undergoing surgical management for symptomatic persistent olecranon physeal abnormalities were reviewed. Preoperative data, intraoperative findings, and postoperative clinical outcomes including physical examination findings, radiographs, complications, and reoperations were analyzed.

RESULTS

A total of 13 elbows in 12 patients (100% male; average age, 18 ± 4 years) were identified. All patients were pitchers at the high-school or college level. Two unique radiographic patterns were identified: distal persistent olecranon physis (n = 9), identified by an irregular sclerotic lucency at the site of the olecranon physis; and proximal persistent olecranon physis (n = 4), identified by a radiolucency exiting proximal to the triceps insertion at the site of an accessory ossification center that failed to unite. Surgical management included débridement, autograft bone grafting, and internal fixation. There were 3 reoperations (1 for infection, 2 for painful hardware). All patients achieved successful radiographic union (average, 8 ± 2 weeks). At an average follow-up of 4.4 ± 1.2 years, the average postoperative Disabilities of the Arm, Shoulder, and Hand score was 1.1 ± 1.6; the Mayo Elbow Performance Score was 98.5 ± 2.4; the American Shoulder and Elbow Surgeons score was 99.3 ± 0.4; and average Likert score for satisfaction was 9.95 ± 0.2. At final follow-up, there were no significant differences in strength, motion, or stability in comparing the operative with the nonoperative elbow (P > .05 for all).

CONCLUSIONS

Two unique patterns of olecranon physeal abnormalities in young, overhead throwing athletes have been identified. Open reduction with internal fixation is clinically and radiographically successful in obtaining union and symptom resolution in these patients.

Prevalence of posterior elbow problems in Japanese high school baseball players

BACKGROUND

Various posterior elbow problems cause posterior elbow pain among baseball players. We aimed to determine the prevalence and diagnoses associated with posterior elbow problems and post-treatment recovery time for returning to sports in Japanese high school baseball players when treated in the off-season.

METHODS

A total of 576 Japanese high school baseball players who participated in baseball skill training camp during the off-season were enrolled in the study. The elbow of each player's throwing arm was assessed by use of a questionnaire and physical examination. Players with abnormal results were advised to visit the hospital. Players who visited the hospital were initially treated conservatively and underwent surgery if necessary. Retrospectively, players with positive physical examination results associated with posterior elbow pain, defined as olecranon tenderness and/or a positive elbow extension impingement test, were selected. Information about their position, elbow pain, physical examination results, diagnosis, treatment, and recovery time before returning to playing sports was assessed.

RESULTS

Olecranon tenderness and/or positive elbow extension impingement test results were found in 76 players (13.2%). Of these, 33 agreed to visit the hospital for further diagnostic imaging and 25 players (75.8%) were diagnosed with posteromedial elbow impingement. By the next spring, 87.9% of players returned to sport, and 100% of players returned to sport before the next summer. The average recovery period was 77 ± 47 days.

CONCLUSION

Physical examinations related to posterior elbow injuries were positive in 13.2% of high school baseball players. The most common diagnosis for posterior elbow pain was posteromedial elbow impingement. All players returned to competitive sports activity levels within 77 ± 47 days.

Alteration of Stress Distribution Patterns in Symptomatic Valgus Instability of the Elbow in Baseball Players: A Computed Tomography Osteoabsorptiometry Study

BACKGROUND

Repetitive valgus stress applied during a throwing motion can lead to various elbow disturbances, including ulnar collateral ligament (UCL) injury. Subchondral bone density reportedly reflects the cumulative force on a joint surface under actual loading conditions.

PURPOSE

(1) To evaluate the distribution of subchondral bone density across the elbow joint in asymptomatic baseball pitchers and symptomatic valgus instability pitchers and (2) to clarify the alterations in stress distribution pattern associated with symptomatic UCL insufficiency pitching activities.

STUDY DESIGN

Controlled laboratory study.

METHODS

Computed tomography (CT) imaging data were collected from the dominant-side elbow of 7 nonathletic volunteers (controls), 12 asymptomatic pitchers (asymptomatic group), and 12 symptomatic valgus instability pitchers with UCL insufficiency (symptomatic group). Bone mineral density across the elbow joint was measured with CT osteoabsorptiometry. A 2-dimensional mapping model was divided into 4 areas of the distal end of the humerus and 5 areas of the ulna with the radial head. The locations and percentages of high-density areas on the articular surface were quantitatively analyzed.

RESULTS

High-density areas in the asymptomatic and symptomatic groups were found in the anterolateral and posteromedial parts of the humerus and in the radial head, posteromedial to the ulna. The high-density areas in the anterior and posteromedial of the humerus, the radial head, and the posteromedial part of the ulna in the controls were smaller than those in the baseball group. In the symptomatic group, the percentages of high-density areas in the anterolateral part of the humerus (mean, 36.3%; 95% CI, 31.9%-40.7%) and the anterolateral part of the ulna (mean, 31.7%; 95% CI, 24.3%-39.1) were significantly greater than those in the asymptomatic group (P = .047 and P < .0001, respectively).

CONCLUSION

Symptomatic UCL insufficiency was associated with characteristic high-stress distribution patterns on the anterolateral part of the capitellum and the anterolateral part of the ulna. The current results indicate that symptomatic UCL insufficiency produces excessive and cumulative stress in the elbow joint.

CLINICAL RELEVANCE

The information obtained from the CT images can useful for early detection of overstress conditions of the elbow joint.

Elbow Trauma in the Athlete

In caring for athletes, the physician must be able to accurately diagnose and appropriately treat all forms of elbow injuries. Traumatic injuries to the elbow are common in the athlete. The late cocking phase of throwing produces tremendous valgus stress on the elbow that can lead to medial epicondyle avulsion fractures in adolescents or rupture of the medial ulnar collateral ligament in skeletally mature overhead throwers, such as baseball pitchers and javelin throwers. Common traumatic elbow injuries suffered by athletes, surgical techniques for operative repair of these injuries, as well as postoperative rehabilitation protocols and the clinical results are presented.

The thrower's elbow

Overhead throwing activities expose the elbow to tremendous valgus stress, making athletes vulnerable to a specific constellation of injuries. Although baseball players, in particular pitchers, are the athletes affected most commonly, overhead throwing athletes in football, volleyball, tennis, and javelin tossing also are affected. The purpose of this review is to review the anatomy, biomechanics, pathophysiology, and treatment of elbow disorders related to overhead throwing athletes. Although focus is on management of ulnar collateral ligament injuries, all common pathologies are discussed.

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.