Tetsuya Matsuura

The Most Effective Exercise for Strengthening the Supraspinatus Muscle Evaluation by Magnetic Resonance Imaging

Background Electromyography has been used to determine the best exercise for strengthening the supraspinatus muscle, but conflicting results have been reported. Magnetic resonance imaging T2 relaxation time appears to be more accurate in determining muscle activation. Purpose To determine the best exercises for strengthening the supraspinatus muscle. Study Design Criterion standard. Methods Six male volunteers performed three exercises: the empty can, the full can, and horizontal abduction. Immediately before and after each exercise, magnetic resonance imaging examinations were performed and changes in relaxation time for the subscapularis, supraspinatus, infraspinatus, teres minor, and deltoid muscles were recorded. Results The supraspinatus muscle had the greatest change among the studied muscles in relaxation time for the empty can (10.5 ms) and full can (10.5 ms) exercises. After the horizontal abduction exercise the change in relaxation time for the supraspinatus muscle (3.6 ms) was significantly smaller than that for the posterior deltoid muscle (11.5 ms) and not significantly different from that of the other muscles studied. Conclusion The empty can and full can exercises were most effective in activating the supraspinatus muscle.

Conservative Treatment for Osteochondrosis of the Humeral Capitellum

Background Conservative treatment is recommended for the early stage of osteochondrosis of the humeral capitellum. However, the outcome of conservative treatment has not been well documented. Hypothesis Osteochondrosis of the humeral capitellum detected at an early stage responds well to conservative treatment. Study Design Cohort study; Level of evidence, 3. Methods We retrospectively reviewed 176 patients with osteochondrosis of the humeral capitellum. There were 134 lesions that were stage I (radiolucent area) in patients with a mean age of 11.5 years and 42 lesions that were stage II (nondisplaced fragments) in patients with a mean age of 13.9 years based on anteroposterior radiographs of the elbow in 45° of flexion. Conservative treatment was performed on 101 patients. The remaining 75 patients did not follow the authors’ advice. Conservative treatment consisted of discontinuation of heavy use of the elbow for at least 6 months. Follow-up radiographs were taken at 1 -month intervals. At a mean follow-up of 24 months, all patients were evaluated clinically and radiographically. Results Conservative management produced healing in 90.5% of stage I lesions and 52.9% of stage II lesions. The mean period required for healing was 14.9 months in stage I and 12.3 months in stage II. Sixty-six of 84 (78.6%) stage I patients and 9 of 17 (52.9%) stage II patients returned to competitive-level baseball. Of the 75 patients who did not follow our advice, healing was observed in 17 (22.7%). The healing rate was higher for the 101 patients who followed our advice as opposed to the 75 patients who did not. Conclusion Osteochondrosis of the humeral capitellum can be successfully treated conservatively if treatment is begun in an early stage of the disease.

Hamstring muscle function after tendon harvest for anterior cruciate ligament reconstruction: evaluation with T2 relaxation time of magnetic resonance imaging.

Background Regeneration of the semitendinosus and gracilis tendons after harvesting for anterior cruciate ligament reconstruction has been reported; however, muscle belly function after tendon regeneration has not been well documented. Hypothesis The semitendinosus and gracilis muscles are highly activated during knee flexion if their tendons are well regenerated after anterior cruciate ligament reconstruction. Study Design Descriptive laboratory study. Methods Hamstring muscle activation in 11 patients who had undergone anterior cruciate ligament reconstruction with semitendinosus and gracilis tendons was evaluated by measuring the increase of T2 relaxation time measured via magnetic resonance imaging after knee flexion exercise. Tendon regeneration was evaluated via magnetic resonance imaging. Results Both muscles increased T2 relaxation time after knee flexion exercise in the operated legs, and there was no significant difference in those values between the operated and nonoperated legs. All the semitendinosus tendons were regenerated at or below the joint line, but no gracilis tendons were observed beyond the joint line. The results indicated that both muscles were highly recruited during knee flexion, regardless of the degree of their tendon regeneration. Conclusion The semitendinosus and gracilis muscles are able to restore or maintain their contractile capability after harvest of their tendons for anterior cruciate ligament reconstruction, regardless of the degree of regeneration.

The Value of Using Radiographic Criteria for the Treatment of Persistent Symptomatic Olecranon Physis in Adolescent Throwing Athletes

Background Previously published reports present a variety of nonoperative and operative treatments for a persistent olecranon physis. However, the radiographic indication for the operative treatment is not clear. Hypothesis Our radiographic classification of persistent olecranon physis is helpful in formulating treatment decisions. Study Design: Cohort study; Level of evidence, 3. Methods Sixteen male baseball players with persistent olecranon physis were retrospectively evaluated. The mean age at first presentation was 14.7 years (range, 12-17 years). The lesion was classified into 2 stages based on radiographic appearance. Stage I demonstrated widening of the olecranon epiphyseal plate when compared with the contralateral elbow on the lateral view. Sclerotic change indicated stage II. All patients underwent nonoperative treatment for at least 3 months. Follow-up radiographs were taken at 1-month intervals. Operative treatment was provided to the patients whose condition had failed to improve after nonoperative treatment. Results Of the 16 patients, 12 had stage I lesions and 4 had stage II lesions. Nonoperative management produced healing in 91.7% of patients with stage I lesions and none of the patients with stage II lesions. Conclusion Our radiographic classification of persistent olecranon physis is useful for treatment decision making. In addition, our results demonstrated that sclerotic change is a high predictive indicator of the need for operative treatment.

Prevalence of Osteochondritis Dissecans of the Capitellum in Young Baseball Players Results Based on Ultrasonographic Findings

Background: Osteochondritis dissecans (OCD) of the capitellum is a well-recognized cause of elbow pain and disability in adolescent athletes. However, little is known about the prevalence of OCD in adolescent baseball players. Purpose: To determine the prevalence of OCD in baseball players aged 10 to 12 years based on ultrasonographic findings and to investigate the clinical characteristics of those with OCD lesions. Study Design: Descriptive epidemiology study. Methods: A total of 1040 players aged 10 to 12 years completed a questionnaire, ultrasound imaging, and radiographic examination to investigate OCD. Sonographic findings were classified into 5 grades (0, 1a, 1b, 2, and 3). Subjects with grade 1a, 1b, 2, or 3 were considered to have abnormal findings of the capitellum and were advised to undergo radiography. Radiographic and ultrasonographic findings were then compared. The prevalence of OCD was calculated, and differences by age and player position were determined. Results: Of the 1040 players, 33 (3.2%) had an abnormal finding on initial ultrasonography screening, and all 33 agreed to undergo radiography. Of them, 22 (66.7%) were found to have OCD of the capitellum on radiographs, giving an overall prevalence of 2.1%. Seven subjects (31.8%) had no history of elbow pain. Based on the radiographic classification, 20 subjects (90.9%) had stage I lesions. Analysis of OCD by age and player position revealed no significant differences. Conclusion: The prevalence of OCD of the capitellum was 2.1% in 1000 baseball players aged 10 to 12 years, with no differences in prevalence according to age or player position.

Elbow Injuries in Youth Baseball Players Without Prior Elbow Pain: A 1-Year Prospective Study

Background: Many risk factors for throwing injuries have been proposed. However, little is known about the risk factors for elbow injuries, particularly on physeal injuries in youth baseball players without prior elbow pain. Purpose: To investigate the risk factors for elbow injuries with a focus on physeal injuries that could predispose youth baseball players without elbow pain to elbow injuries. Study Design: A prospective epidemiology study. Methods: In 2006, 449 players without prior elbow pain were observed prospectively for 1 season to study injury incidence in relation to specific risk factors. The average age was 10.1 years (range, 7-11 years). One year later, all players were examined by administering a questionnaire, physical examination, and radiographic examination. Data for the groups with and without elbow pain were analyzed using multivariate logistic regression models. Results: Among the 449 participants, 30.5% reported episodes of elbow pain during the season. Of the players who reported elbow pain, 72.3% presented abnormal findings on physical examination, and of those players, 81.4% had radiographic abnormalities. Multivariate analysis showed that the age of 12 years (at 1-year examination), pitcher and catcher positions, and playing more than 100 games per year were risk factors for elbow pain. Conclusion: It is expected that 30% of youth baseball players have elbow pain each year, and nearly 60% of players with elbow pain exhibit radiographic abnormalities. The age of 12 years, pitcher and catcher positions, and playing more than 100 games per year are risk factors for elbow pain.

Epidemiology of shoulder and elbow pain in youth baseball players

ABSTRACT Objectives: There are relatively few published epidemiological studies examining the differences in the risk of shoulder and elbow pain in young baseball players. The purpose of this study was to investigate risk factors for shoulder and elbow pain in child and adolescent baseball players. Methods: A total of 1563 players aged 7 to 12 years participated in this investigation. Subjects were asked whether they had experienced episodes of shoulder or elbow pain. We investigated the following risk factors for shoulder and elbow pain: age, position, years of baseball experience, and training hours per week. Data from the groups with and without shoulder and elbow pain were analyzed using multivariate logistic regression models. Results: Among the 1563 participants, 15.9% and 29.2% reported episodes of shoulder and elbow pain, respectively. Multivariate analysis showed that shoulder pain was associated with age 10, 11, and 12 years, and that elbow pain was associated with age 10, 11, and 12 years, playing catcher, and >2 years of baseball experience. Training hours per week were not associated with either shoulder or elbow pain. Conclusion: In over 1000 baseball players aged 7 to 12 years, 15.9% reported episodes of shoulder pain, while 29.2% reported elbow pain in the throwing arm. The associated risk factors were different for each type of pain. Shoulder pain was associated with increased age while elbow pain was associated with increased age, increased years of baseball experience, and playing catcher.

Foraminoplastic transforaminal percutaneous endoscopic discectomy at the lumbosacral junction under local anesthesia in an elite rugby player

Percutaneous endoscopic discectomy (PED) is the least invasive disc surgery available at present. The procedure can be performed under local anesthesia and requires only an 8 mm skin incision. Furthermore, damage to the back muscle is considered minimal, which is particularly important for disc surgery in athletes. However, employing the transforaminal (TF) PED approach at the lumbosacral junction can be challenging due to anatomical constraints imposed by the iliac crest. In such cases, foraminoplasty is required in addition to the standard TF procedure. A 28-year-old man who was a very active rugby player visited us complaining of lower back and left leg pain. His visual analog scale (VAS) score for pain was 8/10 and 3/10, respectively. MRI revealed a herniated nucleus pulposus at L5-S level. TF-PED was planned; however, the anatomy of the iliac crest was later found to prevent access to the herniated mass. Foraminoplasty was therefore performed to enlarge the foramen, thereby allowing a cannula to be passed through the foramen into the canal without causing exiting nerve injury. The herniated mass was then successfully removed via the TF-PED procedure. Pain resolved after surgery, and his VAS score decreased to 0/10 for both back and leg pain. The patient returned to full rugby activity 8 weeks after surgery. In conclusion, even with an intracanalicular herniated mass at the lumbosacral junction, a TF-PED procedure is possible if additional foraminoplasty is adequately performed to enlarge the foramen.

Angiogenesis and myogenesis in mouse tibialis anterior muscles during distraction osteogenesis: VEGF, its receptors, and myogenin genes expression.

Angiogenesis and myogenesis occur in the surrounding skeletal muscles following distraction osteogenesis, but their molecular mechanisms remain unclear. The present study investigated morphological features of lengthened muscles and the time course change of vascular endothelial growth factor (VEGF), its receptors (VEGFR‐1 and VEGFR‐2) and myogenin gene expression profiles related to angiogenesis and myogenesis in tibialis anterior (TA) muscles with a mouse model of distraction osteogenesis, which involves 1 week of waiting period (latency phase), 2 weeks of intermittent distraction (distraction phase), and 5 weeks of remodeling period (consolidation phase). Macroscopic findings showed that lengthened TA muscles increased to approximately 42% longer and 10% heavier at the end of the process when compared to pre‐surgery. During the distraction phase, VEGF and its receptors were induced in the vascular endothelial cells, myogenin‐positive satellite cells and myocytes, and subsequently, capillary progression and myogenesis were increased. Real‐time RT‐PCR showed that Vegf, Vegfr‐1, Vegfr‐2, and myogenin genes expression was enhanced during the muscle lengthening. Vegf and Vegfr‐1 were upregulated following the recession of angiogenesis at the consolidation phase. We conclude that upregulation of VEGF and its receptors by mechanical tension‐stress could be involved in the process of angiogenesis and myogenesis in lengthened muscles.

State-of-the-art ultrasonographic findings in lower extremity sports injuries

Athletes sometimes experience overuse injuries. To diagnose these injuries, ultrasonography is often more useful than plain radiography, computed tomography (CT), or magnetic resonance imaging (MRI). Ultrasonography can show both bone and soft tissue from various angles as needed, providing great detail in many cases. In conditions such as osteochondrosis or enthesopathies such as Osgood-Schlatter disease, Sinding-Larsen-Johansson disease, bipartite patella, osteochondritis dissecans of the knee, painful accessory navicular,and jumpers knee, ultrasonography can reveal certain types of bony irregularities or neovascularization of the surrounding tissue. In patients of enthesopathy, ultrasonography can show the degenerative changes at the insertion of the tendon. Given its usefulness in treatment, ultrasonography is expected to become essential in the management of overuse injuries affecting the lower limb in athletes. J. Med. Invest. 62: 109-113, August, 2015.