Two-year follow-up study of subchondral surface irregularities of the capitellum on ultrasonography in baseball players under the age of 10 years

Deep Learning-Based Computer-Aided Diagnosis of Osteochondritis Dissecans of the Humeral Capitellum Using Ultrasound Images

BACKGROUND

Ultrasonography is used to diagnose osteochondritis dissecans (OCD) of the humerus; however, its reliability depends on the technical proficiency of the examiner. Recently, computer-aided diagnosis (CAD) using deep learning has been applied in the field of medical science, and high diagnostic accuracy has been reported. We aimed to develop a deep learning-based CAD system for OCD detection on ultrasound images and to evaluate the accuracy of OCD detection using the CAD system.

METHODS

The CAD process comprises 2 steps: humeral capitellum detection using an object-detection algorithm and OCD classification using an image classification network. Four-directional ultrasound images of the elbow of the throwing arm of 196 baseball players (mean age, 11.2 years), including 104 players with normal findings and 92 with OCD, were used for training and validation. An external dataset of 20 baseball players (10 with normal findings and 10 with OCD) was used to evaluate the accuracy of the CAD system. A confusion matrix and the area under the receiver operating characteristic curve (AUC) were used to evaluate the system.

RESULTS

Clinical evaluation using the external dataset resulted in high AUCs in all 4 directions: 0.969 for the anterior long axis, 0.966 for the anterior short axis, 0.996 for the posterior long axis, and 0.993 for the posterior short axis. The accuracy of OCD detection thus exceeded 0.9 in all 4 directions.

CONCLUSIONS

We propose a deep learning-based CAD system to detect OCD lesions on ultrasound images. The CAD system achieved high accuracy in all 4 directions of the elbow. This CAD system with a deep learning model may be useful for OCD screening during medical checkups to reduce the probability of missing an OCD lesion.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Prevalence of osteochondritis dissecans of the capitellum in elementary school baseball players based on ultrasonographic screening: a 15-year overview in Tokushima, Japan

Background

Although several operative procedures have evolved for capitellar osteochondritis dissecans (OCD), the best outcome is achieved by early detection and conservative treatment. The objective of this study was to clarify changes in the prevalence of capitellar OCD in young baseball players over a long-term period based on consistent criteria in Tokushima, Japan between 2006 and 2020.

Methods

The number of players who underwent screening and the discovery rate of capitellar OCD during the study period were investigated. School grade and radiographic stage were also evaluated.

Results

The confirmation rate was significantly higher when ultrasonographic screening was performed than when screening was based on physical findings (65.8% vs. 1.9%, P < .001). The overall incidence of OCD in elementary school players based on ultrasonographic screening was 1.4% during the 10-year study period. Twenty-one (10.8%) of the 195 players identified to have OCD had experienced lateral elbow pain. When classified radiographically, the lesion was stage I in 73.3% of cases, stage II in 24.1%, and stage III in 2.6%. No cases of OCD were diagnosed before the fourth grade. The prevalence rates increased gradually from the fourth grade to the sixth grade.

Conclusion

Ultrasonographic screening could be more effective for detecting capitellar OCD than screening based on physical findings. The overall prevalence of OCD among elementary school players was 1.4% over 10 years. The prevalence rates increased gradually from the fourth grade onwards.

Deep learning-based osteochondritis dissecans detection in ultrasound images with humeral capitellum localization

PURPOSE

Osteochondritis dissecans (OCD) of the humeral capitellum is a common cause of elbow disorders, particularly among young throwing athletes. Conservative treatment is the preferred treatment for managing OCD, and early intervention significantly influences the possibility of complete disease resolution. The purpose of this study is to develop a deep learning-based classification model in ultrasound images for computer-aided diagnosis.

METHODS

This paper proposes a deep learning-based OCD classification method in ultrasound images. The proposed method first detects the humeral capitellum detection using YOLO and then estimates the OCD probability of the detected region probability using VGG16. We hypothesis that the performance will be improved by eliminating unnecessary regions. To validate the performance of the proposed method, it was applied to 158 subjects (OCD: 67, Normal: 91) using five-fold-cross-validation.

RESULTS

The study demonstrated that the humeral capitellum detection achieved a mean average precision (mAP) of over 0.95, while OCD probability estimation achieved an average accuracy of 0.890, precision of 0.888, recall of 0.927, F1 score of 0.894, and an area under the curve (AUC) of 0.962. On the other hand, when the classification model was constructed for the entire image, accuracy, precision, recall, F1 score, and AUC were 0.806, 0.806, 0.932, 0.843, and 0.928, respectively. The findings suggest the high-performance potential of the proposed model for OCD classification in ultrasonic images.

CONCLUSION

This paper introduces a deep learning-based OCD classification method. The experimental results emphasize the effectiveness of focusing on the humeral capitellum for OCD classification in ultrasound images. Future work should involve evaluating the effectiveness of employing the proposed method by physicians during medical check-ups for OCD.

One-year follow-up ultrasonographic study of the subchondral bone surface of the distal femoral epiphysis in children aged 9-11 years

The aim of this study was to investigate the subchondral bone surface of the distal femoral epiphysis and monitor the morphologic changes on ultrasonography (US) in growing children. A total of 160 football players aged 9-11 years underwent ultrasonographic examination of both knees. The regularity of the subchondral bone surface of the femoral condyles was classified as grade 0 (smooth), 1 (focal semilunar depression or indentation) or 2 (broad irregularity). The relationship between age and frequency of irregularity was analyzed. Children with a grade 2 were referred for radiography and MRI to check for osteochondritis dissecans (OCD). All players underwent repeat examination 1 year later. On initial examination, 82/320 knees (25.6%) were categorized as grade 0, 237/320 (74.1%) as grade 1 and 1 (0.3%) as grade 2. Logistic regression analysis revealed a significant association of increasing age with decreased irregularity of subchondral bone in the lateral and medial condyles (P = 0.019 and P < 0.001 for trend, respectively). One year later, logistic regression analysis showed that increasing age was significantly associated with decreased appearance of subchondral bone irregularity in the medial condyle (P = 0.005 for trend) and a greater likelihood of disappearance of irregularity in both condyles (P < 0.001 for trend). Of five knees classified as grade 2, four had evidence of OCD on radiography and MRI. Subchondral bone surface irregularity of the distal femoral epiphysis was more common on US in growing children aged 9-11 years, and transition from an irregular to a smooth outline accelerated after age 10 years. US is a reliable method for assessing the morphology of the distal femoral epiphysis and could be a useful screening tool for detecting OCD.

Limiting the Pitch Count in Youth Baseball Pitchers Decreases Elbow Pain

Background

Reducing the number of pitches thrown is regarded as the most effective way to prevent throwing injuries in youth baseball pitchers. However, few studies have compared the effectiveness of limiting the pitch count versus the limiting the number of innings pitched in terms of elbow injuries.

Hypothesis

We hypothesized that, compared with inning limits, pitch count limits would lead to greater decreases in elbow pain, range of motion deficits, positive moving valgus stress test results, and the risk of capitellar osteochondritis dissecans (OCD).

Study Design

Cohort study; Level of evidence, 3.

Methods

This study retrospectively reviewed baseball pitchers aged 8 to 12 years in 2017 and 2018. Inning and pitch count limits in games were set to a daily maximum of 7 innings in 2017 and 70 pitches in 2018. Elbow pain, range of motion, and moving valgus stress test results were evaluated. The presence of capitellar OCD was assessed on ultrasonographic and radiographic images.

Results

A total of 352 pitchers in 2017 and 367 pitchers in 2018 participated. The mean pitch count per game was lower in the pitch count limit (CL) group (52.5 ± 16.0) than in the inning limit (IL) group (98.2 ± 19.5) (P < .001). Compared with the IL group, the CL group had significantly lower rates of elbow pain (40.9% vs 31.9%, respectively; P = .01) and reduced flexion (19.0% vs 10.6%, respectively; P = .001). Multivariate analysis revealed a significant association between elbow pain and age in both the IL and the CL groups (P < .0001 and P = .02, respectively) and between OCD and elbow pain in the CL group (P = .04).

Conclusion

A pitch count limit of ≤70 pitches per day for baseball pitchers ≤12 years could be more protective against elbow pain and reduced flexion than a limit of ≤7 innings per day, but it may not be effective for reducing the risk of capitellar OCD.

Osteochondritis Dissecans of the Capitellum :Review of the Literature

Osteochondritis dissecans (OCD) of the capitellum is a leading cause of elbow disability in adolescent baseball players. Previous studies have not found an association of player position with capitellar OCD. Elbow pain and a longer playing history might be related to progression of capitellar OCD but do not in themselves increase the risk of development of the condition. The cause of capitellar OCD is likely to include a combination of repetitive microtrauma and internal factors, such as ischemia and genetic predisposition. A combination of radiography, computed tomography, magnetic resonance imaging, and ultrasonography have aided our understanding of the pathology of capitellar OCD. Screening using ultrasonography enables early detection and provides an opportunity for successful conservative treatment. Treatment has conventionally included both operative and nonoperative measures based on the stage and size of the lesion, skeletal maturity, subjective symptoms, and structural integrity of the cartilage. Early-stage lesions respond better to nonoperative treatment than those in more advanced stages. Operative indications include persistent symptoms despite nonoperative treatment, symptomatic loose bodies, and displacement or detachment of fragments. J. Med. Invest. 67 : 217-221, August, 2020.

Cumulative Incidence of Osteochondritis Dissecans of the Capitellum in Preadolescent Baseball Players

PURPOSE

To quantify the 1-year cumulative incidence of capitellar osteochondritis dissecans (OCD) in preadolescent baseball players and identify the risk factors associated with this condition.

METHODS

In total, 1,275 school-aged baseball players (aged 6-11 years) without an established diagnosis of capitellar OCD were enrolled in this longitudinal, observational study. One year later, all players underwent ultrasonographic examination of the throwing elbow on the playing field. Elbows with abnormal ultrasonographic findings at this time then underwent radiographic examination. Data for the groups with and without capitellar OCD were analyzed using multivariate logistic regression models.

RESULTS

The 1-year cumulative incidence of capitellar OCD was 1.8% (95% confidence interval, 1.1%-2.7%). On multivariate analysis, players aged 10 to 11 years were 3.96 times more likely to have capitellar OCD (95% confidence interval, 1.10-18.97) than those aged 6 to 9 years; however, starting baseball at an earlier age, number of years played, training hours per week, player position, and history of elbow pain were not significantly associated with capitellar OCD. Only 34.8% of players with capitellar OCD reported elbow pain.

CONCLUSIONS

The risk of OCD of the capitellum developing within a 1-year period in preadolescent baseball players was 1.8%. Players aged 10 to 11 years had a significantly greater risk of capitellar OCD development than those aged 6 to 9 years.

LEVEL OF EVIDENCE

Level III, local nonrandom sample cohort.

Editorial Commentary: "There's No Crying in Baseball," But There Is Osteochondritis Dissecans of the Elbow

Osteochondritis dissecans of the capitellum is a rare and ultrasonically identifiable disease of the dominant elbow of preadolescent baseball players as young as 9 years of age. We must choose to protect these young players, either by initiating a screening program to identify the disease at an early stage when treatment results in an acceptable lifelong outcome or by vociferously limiting the daily, weekly, and yearly participation in this vulnerable group.