Methods: The study included 85 players. Participants were divided into two groups: pitchers and fielders. The association between the laterality of spondylolysis and the throwing/batting side in the overall cohort and between the two groups was evaluated. Results: Among pitchers, 16 lesions appeared on the throwing side and 32 on the nonthrowing side (p =0.029). For fielders, no notable difference was observed between the two sides (p =0.363). Furthermore, batting preference did not influence the laterality of spondylolysis in either group. Conclusions Adolescent baseball players, particularly pitchers, exhibited a higher incidence of lumbar spondylolysis on the side opposite their throwing arm. The findings of this study highlight the significant effect of asymmetrical sporting activities on the development of spondylolysis, to which pitchers are particularly susceptible.

Knee swelling after total knee arthroplasty (TKA) is common and can lead to loss of functional performance. The aim of this study was to reveal the factors related to knee swelling after TKA. In total, 86 patients who underwent unilateral TKA were enrolled. Changes in thigh circumference at 0, 5, and 10 cm proximal from upper pole of the patella were evaluated. In addition, age, body mass index, operation time, blood loss volume, C-reactive protein, albumin, and D-dimer levels, and changes in knee flexion were also assessed preoperatively and at 7 days postoperatively. Thigh circumference at all sites increased postoperatively. Changes in thigh circumference at the superior edge of the patella correlated with changes in knee flexion (r =－0.33, p < 0.01). No significant correlation was found between the other factors. In conclusion, this study revealed a correlation between swelling and flexion after TKA, but no correlation between other factors pre-, intra-, or postoperatively. It is thus necessary to consider other factors in the future.

Objective: As a minimal invasive surgery for the treatment of thumb carpometacarpal joint (trapeziometacarpal [TMC]) arthritis, we performed an arthroscopic synovectomy for Eaton stage II to IV arthritis.Patients and Methods: We included patients who were effectively treated with a corticosteroid injection, experienced recurrence of TMC pain, and had no major instability of the TMC. Surgery was performed in 17 female patients. Synovectomy was performed, when possible, using radiofrequency and a shaver. The mean follow-up period was 27.2 months.Results: Two patients required additional surgery; however, 15 patients were satisfied with the outcome. The mean visual analogue scale score improved from 8.8 preoperatively to 2.2 postoperatively.Conclusion: Arthroscopic synovectomy is indicated to be an effective treatment for stage II to IV TMC arthritis. The goal of this treatment was to relieve severe pain minimally invasively. Furthermore, if symptoms remain or reoccur, another curative procedure can be chosen.

Objective: Lumbar spondylolysis, caused by stress fracture of the pars interarticularis may lead to a bony defect or spondylolisthesis. In adolescents, its surgical treatment employs the smiley face rod method for direct reduction of pseudoarthrotic spondylolysis and spondylolisthesis. Clinical outcomes of this treatment have been occasionally described; however, implant removal has not been discussed previously. We present a patient with lumbar spondylolysis with grade 1 slip at the 5th lumbar vertebra (L5) per the Meyerding classification.Patient: A 14-year-old boy presented with chronic severe lower back pain. Since conservative therapy did not resolve pain or enable resuming sports activities, the smiley face rod repair was performed 7 months after the initial treatment.Result: Anterior slippage of the L5 was surgically reduced. The patient wore a brace for 3 months postoperatively, and partial bone fusion was noted 6 months postoperatively. He resumed his sports activity 8 months postoperatively, and absolute bone fusion was confirmed 18 months postoperatively. Implant removal was performed 3 years postoperatively. Grade 1 slip was corrected with absolute bone fusion, and long-term follow-up revealed good results in terms of healing and rehabilitation.Conclusion: Smiley face rod method that allows for implant removal after bone fusion is suitable for adolescents.

Objective: The aim of this study was to determine the prevalence of curable and pseudoarthrosis stages of adolescent lumbar spondylolysis under high school students complaining of and seeking medical consultation for low back pain.Patients and Methods: We analyzed age, sex, morbidity, presence of spina bifida occulta (SBO), and competitive sport discipline of patients with lumbar spondylolysis. We then stratified their pathological stage using a modified classification system via magnetic resonance imaging and computed tomography.Results: Of 507 patients, 451 lesions in 268 patients were diagnosed with lumbar spondylolysis (average age, 14.7 years; sex ratio, 215:53 male/female). Morbidity levels were as follows: L1, 1 lesion in 1 patient; L2, 9 lesions in 5 patients; L3, 38 lesions in 25 patients; L4, 106 lesions in 74 patients; L5, 297 lesions in 189 patients, and SBO verified in 111 patients. A total of 264 patients played a specific sport: baseball, 93; soccer, 49; volleyball, 21; track and field, 21; basketball, 20; others, 164. The prevalence of curable- and pseudoarthrosis-stage lumbar spondylolysis was 206 lesions in 142 patients, and 141 lesions in 87 patients, respectively.Conclusion: With 59.3% of patients having curable-stage lumbar spondylolysis, adolescent athletes with low back pain are urged to seek consultation. Furthermore, clinicians should perform magnetic resonance imaging to avoid misdiagnosis.

Objective: Spontaneous spinal epidural hematoma is rare and therefore difficult to diagnose. This study evaluated the clinical features of this condition in patients admitted to our hospital.Patients and Methods: We evaluated 12 patients with spontaneous spinal epidural hematoma who were treated at our hospital. We investigated the following variables in these patients: underlying diseases, medications used, initial symptoms, spinal level affected, whether transported to the hospital by ambulance, department where first evaluated, mass lesion on computed tomography with soft tissue window settings, time interval between symptom onset and diagnosis, treatment received, and Frankel classification on arrival and when last observed.Results: Five patients reported the use of antiplatelet or anticoagulant drugs. All patients in this study reported acute onset of severe pain as the initial symptom, and 10 patients reported some degree of paralysis accompanying the pain. With respect to the morbidity level, the cervical region was the most common site of involvement (n=7). Ten patients were transported to the hospital at night via ambulance. Five patients first visited the Department of Internal Medicine. Seven patients presented with a mass lesion on computed tomography with soft tissue window settings. The time interval between symptom onset and diagnosis ranged from 2 hours to 6 days. Three and 9 patients received conservative and surgical treatments, respectively. No patient showed worsening of Frankel classification.Conclusion: Acute onset of severe pain was the most characteristic clinical symptom. Spontaneous spinal epidural hematoma should be included in the differential diagnosis. Computed tomography with soft tissue window settings may rule out cerebrovascular disease and cardiovascular disease, and specifically detect a hematoma. Subsequent magnetic resonance imaging can diagnose a spontaneous spinal epidural hematoma at an early stage.

Purpose: This study aimed to examine the characteristics of lumbar spondylolysis with acute lumbar spondylolysis on one side and pseudoarthrotic spondylolysis on the other, relative to acute lumbar spondylolysis on one side only.Patients and Methods: Short-tau inversion recovery images obtained through magnetic resonance imaging were used to diagnose 58 patients with acute lumbar spondylolysis with bone marrow edema on one side only. A total of 20 patients who had pars defects on the contralateral side (terminal-stage pseudoarthrotic spondylolysis) were included in the contralateral pseudoarthrosis group (P group). The remaining 38 patients with normal images for the contralateral pars interarticularis were included in the unilateral lesion group, in which the contralateral side was normal (U group). We investigated the union rate, age, sex, lesion laterality, vertebral level, pathological stage, and existing spina bifida occulta in both groups.Results: The P group was characterized by a higher proportion of right-side cases, L5 lesions, more progressed pathological stage, and spina bifida occulta and a significantly lower union rate than the U group.Conclusion: The union rate in patients with lumbar spondylolysis with acute lumbar spondylolysis on one side and pseudoarthrotic spondylolysis on the opposite side was only 15%. We should inform patients with acute unilateral spondylolysis lesions and contralateral pseudoarthrosis about this poor union rate and urge them to choose their therapy accordingly.

Patients with lumbar spondylolysis may have poor lumbo-pelvic function and improving lumbar segmental stability may take time. It is assumed that the stronger the lordosis, the poorer the lumbo-pelvic function; however, to our knowledge, evidence of this relationship is lacking. To clarify the relationship between lumbosacral alignment and lumbo-pelvic function in lumbar spondylolysis, we assessed lumbar lordosis and sacral slope in the standing lateral view on plain X-rays and Sahrmann Core Stability Test (SCST) results in 66 adolescents with lumbar spondylolysis with bone marrow edema. Based on SCST results, the patients were divided into those with level 1 or 2 core stability (low group) and those with level 3 or higher core stability (high group). No significant difference was found in lumbosacral alignment between the two groups. In adult patients with spondylolisthesis, the lumbar lordosis angle and sacral slope increases to maintain the center of gravity, but no such increase in compensation was evident in our patients who were young and without slip. These findings suggest that lumbo-pelvic function does not affect lumbosacral alignment in adolescents with spondylolysis. It should be noted that using the SCST alone to evaluate motor control may not be precise enough to determine the relationship between lumbosacral alignment and lumbo-pelvic function because the SCST may not have high enough sensitivity to assess trunk extensor muscles.