Efficacy of S-Flurbiprofen Plaster for Analgesia Following Total Hip Arthroplasty.

PURPOSE: S-flurbiprofen (SFP) plaster, a non-steroidal anti-inflammatory drug preparation that penetrates effectively into deep tissue, is currently used as a conservative treatment for osteoarthritis. We investigated the analgesic and adverse effects of SFP plaster after total hip arthroplasty (THA). METHODS: A retrospective comparative study identified 100 patients who underwent primary THA in our department. Group A consisted of 50 patients who received the selective cyclooxygenase-2 inhibitor celecoxib for 14 days after surgery, while Group B consisted of 50 patients who received SFP plaster for 14 days after surgery. We noted the numerical rating pain intensity scale (NRS) score, body temperature, and adverse effects of the analgesics. RESULTS: Groups A and B showed no significant difference in NRS scores (p > 0.05). The body temperature was significantly higher in Group B than in Group A on days one, two, three, and five (p < 0.01). In Group A, two patients (4%) showed drug-induced renal dysfunction, and one patient (2%) showed gastrointestinal disturbance. Patients in Group B showed no systemic or local adverse effects. CONCLUSIONS: The application of SFP plaster after THA provided an analgesic effect similar to that obtained with oral celecoxib without causing obvious side effects. Applying an SFP plaster may be an effective solution for postoperative analgesia.

Investigation of the Usefulness of Implants With Locking Mechanisms for Diffuse Idiopathic Skeletal Hyperostosis (DISH)-Induced Thoracic and Lumbar Fractures in Patients Operated in the Prone Position.

Background Diffuse idiopathic skeletal hyperostosis (DISH) is a disease that causes bone growth in the spine and musculoskeletal system, and even minor trauma can cause fractures that often require surgery. DISH-induced fractures show a tendency for bone loss when operated in the prone position, which can lead to poor fusion and implant failure; therefore, surgery in the lateral recumbent position is often recommended. However, inserting a pedicle screw (PS) in the lateral recumbent position is technically difficult. This study examined the effectiveness of the repair and fixation of thoracic and lumbar spine fractures using implants with locking mechanisms in the prone position in patients with DISH. Methods We retrospectively analyzed the data from 11 patients (six males and five females; mean age: 87 years) who underwent surgery for thoracic and lumbar fractures caused by DISH between December 2023 and June 2024. Surgery was performed in the prone position using PSs or transdiscal screws (TSDs) for DISH. Ennovate® implants manufactured by B-BRAUN were used. The fixed range was three above-three below for PSs and two above-two below for TSDs. The evaluation parameters were the height/level of injury, operative time, blood loss, local kyphosis angle, anterior wall height ratio, and complications. The local kyphosis angle was measured as the angle between the upper and lower endplates of the fractured vertebrae. The ratio of the anterior wall height was evaluated. Results The average operative time was 87 min (52-172 min), and the average blood loss was 40ml (10-140 ml). The preoperative and postoperative local kyphosis angle was -8.7° and -2.4°, respectively, and the average local kyphosis angle improvement was 6.3° (0.1-14°). The preoperative and postoperative anterior wall height ratio was 132% and 110%, respectively, and the average anterior wall height ratio improvement was 22% (2-82%). No complications, such as screw deviation, implant loosening, loss of correction, or skin problems, were observed. Conclusion This study demonstrated that DISH-induced thoracic and lumbar spine fractures could be repaired and fixed using implants with locking mechanisms in the prone position. The prone position is familiar to spine surgeons and is considered safe. Additionally, screw migration may occur due to decreased bone density in the vertebral bodies with DISH; in such cases, it would be better to fix the screw without forcing it to be repositioned.

Alexis® Orthopedic Protector Provides Wound Protection and Aids in Hypertrophic Scar Prevention in Total Hip Arthroplasty.

PURPOSE: Total hip arthroplasty (THA) is one of the most widely performed orthopedic surgeries. Techniques for small skin incisions and preservation of muscles and tendons have been developed. However, avoiding skin complications and muscle damage due to forced deployment and surgical manipulation is challenging. This study aimed to investigate whether the use of Alexis® Orthopedic Protector (Applied Medical Resources Corp., Rancho Santa Margarita, CA, USA) affects postoperative outcomes. METHODS: This was a retrospective cohort study including 118 patients who underwent primary THA by the same surgeon at our single institution between March 2021 and March 2023. Protectors were used alternately for each operation. Fifty-nine patients were in the protector-using group (P group), and 59 were in the nonprotector-using group (N group), with comparisons made between groups. Protectors were placed under the fascia in all patients. RESULTS: Preoperative blood tests showed no difference in renal and hepatic function between the two groups. No differences in postoperative C-reactive protein (CRP) and creatine kinase (CK) values or in the Japanese Orthopedic Association Hip Disease Evaluation Questionnaire (JHEQ) and Numerical Rating Scale (NRS) scores were observed. Postoperative redness was significantly higher in the N group than in the P group (49.2% vs. 7%). The percentage of hypertrophic scars at three months postoperatively was 18.6% in the N group and 7% in the P group. Furthermore, the Japan Scar Workshop Scar Scale (JSS) indicated that hypertrophic scars were significantly worse in the N group than in the P group (p = 0.0012). CONCLUSION: Alexis® Orthopedic Protectors can not only provide short-term wound protection but also reduce the rate and degree of hypertrophic scarring.

Efficiency of Long Lateral Mass Screw in Posterior Cervical Fusion.

INTRODUCTION: Long lateral mass screw (LLMS) technique for posterior cervical fusion has been performed in our hospital since 2019. In this study, the LLMS insertion technique, deviation rate, and insertion torque have been described. Moreover, several major concerns associated with LLMS have been adequately addressed. METHODS: This study included 58 patients (43 men and 15 women) who had undergone LLMS surgery at our hospital during the four-year period from December 2019 to December 2023, and were evaluated using postoperative CT. The evaluation parameters included the screw length at each vertebral segment, screw angle in the sagittal section, distance between the screw heads, and complications. RESULTS: The median screw length at C3 was 23.0 mm (22.0-24.0 mm), the screw angle was 36.1° (31.6-41.8°), and the distance between screw heads was 13.8 mm (11.6-17.2 mm). The median screw length at C4 was 22.0 mm (21.0-24.0 mm), the screw angle was 36.2° (28.7-40.7°), and the distance between screw heads was 15.9 mm (13.0-19.0 mm). The median screw length at C5 was 21.0 mm (20.0-22.0 mm), the screw angle was 35.6° (28.0-39.7°), and the distance between screw heads was 17.6 mm (15.1-20.4 mm). The median screw length for C6 was 20.0 mm (19.0-22.0 mm), the screw angle was 29.2° (25.2-36.8°), and the distance between screw heads was 20.4 mm (16.1-24.4 mm). CONCLUSION: The major limitations of the LLMS technique were inadequate screw angle, difficulty inserting long screws, inadequate decompression, and the inability to perform cervical laminoplasty. However, these limitations did not substantially affect the efficiency of LLMS. LLMS has fewer complications and can insert longer screws than LMS.

Pediatric Traumatic Cervical Distraction Injury: A Case Report.

Spinal cord injury due to trauma is rare in children. We report our experience with the surgical treatment of a cervical spinal cord injury in a one-year-old child with quadriplegia due to traffic trauma. The patient was a girl aged one year and five months. Physical examination findings were quadriplegia and loss of consciousness. Plain computed tomography (CT) of the cervical spine showed a vertical distraction injury of C6/7, and magnetic resonance imaging (MRI) showed spinal cord injuries of C1/2 and C6/7. Based on these findings, a diagnosis of C1/2 and C6/7 spinal cord injury (Frankel A) was made. The patient's state of consciousness did not change during the first week after injury; she was managed systemically with a ventilator. On the 10th day after the injury, her consciousness improved, and she was placed in a pediatric halo vest for weaning. However, as the alignment worsened, we operated. A 5 cm posterior incision was made at the median of C5/6/7. Only the spinous process was deployed, a Nespron tape (Alfresa Pharma Corporation, Osaka, Japan) was wrapped between C5/6 and C6/7, and an autologous iliac bone graft was placed at the C6/7 bilateral facet joint. Six months after surgery, bone fusion was complete. At one year and six months postoperatively, tetraplegia had not improved. Radiographs showed no growth disturbances despite residual alignment abnormalities.

Minimally Invasive Trans-sacral Canal Plasty for Lumbar Canal Stenosis.

Objective The elderly population is increasing in Japan. Along with the increase in the elderly population, the number of patients with lumbar degenerative diseases is also on the rise. In general, elderly patients tend to have more complications and are at higher risk for surgery. Many elderly people suffer from lumbar degenerative disease. We reviewed our initial experience with trans-sacral canal plasty (TSCP) for patients with lumbar spinal canal stenosis and examined the pertinent literature for this report. Methods An analytical observational study was performed on 120 patients with lumbar spinal canal stenosis who underwent TSCP at our single institution from March 2019 to October 2021. These patients had leg pain and/or lower back pain due to degenerative lumbar disease. Patients who had coagulation abnormality, pregnancy, contrast allergy, pyogenic spondylitis, or spinal metastasis were excluded. Results Immediately after TSCP, the average Visual Analog Scale (VAS) score for back pain improved from 58.2 to 29.3, and for leg pain from 72.0 to 31.3. Two years after TSCP, the average VAS score for back pain increased slightly and the average score for leg pain remained almost the same. Additional surgery was performed in 37 of 120 (31%) patients who underwent TSCP. The additional surgery group had significantly worse back pain at one and three months postoperatively than the conservative treatment group. The additional surgery group had significantly worse leg pain immediately after TSCP and at one and three months postoperatively than the conservative treatment group. Logistic regression analysis demonstrated that a decreased spinal canal area (OR 0.986, p = 0.039) was associated with additional surgery. Conclusions We reviewed the outcomes of TSCP at our hospital. The average VAS score for back pain and leg pain improved. However, 31% of patients who underwent TSCP required additional surgery. It was found that the spinal canal area was a major factor in the need for additional surgery.

Advantageous properties of a new fungicide, isofetamid.

The fungicidal properties of a new fungicide, isofetamid, were examined to assess its antifungal spectrum, mode of action, and effects on the infection process of Botrytis cinerea. Additionally, we investigated its fungicidal activity against isolates of B. cinerea resistant to existing fungicides. In mycelial growth inhibition tests, isofetamid exhibited excellent fungicidal activity against ascomycetes but showed no activity against basidiomycetes and oomycetes. Respiratory enzyme assay using mitochondria revealed that isofetamid inhibited succinate dehydrogenase activity prepared from B. cinerea and other ascomycetes fungi used in the study. On the other hand, the activity of mitochondria prepared from Pythium, potato and rat were not inhibited. Isofetamid inhibited also many stages of the infection processes in B. cinerea. Furthermore, it exhibited high fungicidal activity against B. cinerea isolates that were resistant to existing fungicides.

Debridement, Antibiotics, and Implant Retention for a Rare Serratia marcescens Infection after Total Knee Arthroplasty: A Case Report.

Introduction: Recently, Serratia marcescens was reported to cause nosocomial infections. Case Report: In this study, we report a case of S. marcescens infection occurring after total knee arthroplasty (TKA) in a 72-year-old woman. The patient had undergone TKA for knee osteoarthritis. She had a past medical history of diabetes mellitus, for which she was receiving cefazolin sodium. Six days after surgery, redness and effusion were observed in the wound, and post-operative infection was suspected. Thus, the patient was treated with linezolid, clindamycin, and tazobactam/piperacillin hydrate post-operatively. Twelve days after TKA, reinfection was suspected; hence, washing and debridement were repeated. Conclusion: In this case, remission of S. marcescens infection was achieved without the need to remove the implant by cleaning, debridement, and the use of sensitive antimicrobial agents.

Predicting Skeletal-related Events Using SINS.

STUDY DESIGN: Predictive study utilized retrospectively collected data. OBJECTIVE: The primary objective was to evaluate the predictive association between the Spine Instability Neoplastic Score (SINS) and Skeletal-related events (SREs). Secondary objectives included examining characteristics of cases with SINS < 6 among those who developed SRE, and evaluating the impact of additional predictors on prediction accuracy. SUMMARY OF BACKGROUND DATA: Advances in cancer treatment have prolonged the lives of cancer patients, emphasizing the importance of maintaining quality of life. Skeletal-related events from metastatic spinal tumors significantly impact quality of life. However, currently, there is no scientifically established method to predict the occurrence of SRE. SINS, developed by the Spine Oncology Study Group, assesses spinal instability using six categories. Therefore, the predictive performance of SINS for SRE occurrence is of considerable interest to clinicians. METHODS: This predictive study utilized retrospectively collected data from a single-center registry comprising over 1,000 patients with metastatic spinal tumors. SINS and clinical data were collected. Logistic regression was used to create a prediction equation for SRE using SINS. Additional analyses explored factors associated with SRE in patients with SINS < 6. RESULTS: The study included 1,041 patients with metastatic spinal tumors. SRE occurred in 121 cases (12%). The prediction model for SRE using SINS demonstrated an area under the curve (AUC) of 0.832. Characteristics associated with SRE included lower female prevalence, surgeries to primary sites, bone metastases to non-spinal sites, and metastases to other organs. A post hoc analysis incorporating additional predictors improved the AUC to 0.865. CONCLUSION: The SINS demonstrated reasonable predictive performance for SRE within one month of the initial visit. Incorporating additional factors improved prediction accuracy. The study emphasizes the need for a comprehensive clinical prediction model for SRE in metastatic spinal tumors.

Survey of Osteoarthritis of the Shoulder in Patients who Underwent Knee Arthroplasty for Knee Osteoarthritis.

The relationship between osteoarthritis (OA) of the lower extremity and shoulder OA has not been established. This study evaluated the prevalence of shoulder OA in patients with knee OA. We collected contrast-enhanced computed tomography (CECT) images of the shoulder joints of 105 patients with knee OA that were taken 1 week after they underwent primary knee arthroplasty to check for venous thromboembolism (VTE). The images were compared with CECT images of 110 control-group patients that were taken for the purpose of differentiating VTE. Shoulder OA was present in a significantly higher percentage of patients with knee arthroplasty than controls (29% versus 15%), and the difference was particularly pronounced in patients in their 70s (33%) compared to age-matched controls (11%). Patients with knee OA often use arm support to stand up or walk due to knee joint pain and muscle weakness, which places the weight-bearing shoulder at risk of developing OA.

Comparison between Cases of Total Hip Arthroplasty Followed by Colonna Capsular Arthroplasty and Lorenz Cast Reduction in Patients with Developmental Dysplasia of the Hip.

Most patients with developmental dysplasia of the hip (DDH) now receive closed-reduction treatment within 6 months after birth. The long-term outcomes of patients with late-detection DDH have remained unclear. We reviewed the clinical records of 18 patients who underwent Colonna capsular arthroplasty (n=8) or closed reduction (n=10) for developmental dysplasia of the hip as infants or young children and underwent total hip arthroplasty approximately in midlife. Both the Colonna capsular arthroplasty and closed reduction groups achieved good clinical results after total hip arthroplasty. However, the operating time was longer and the improvements of hip range of motion and clinical score were significantly worse in the Colonna capsular arthroplasty group than in the closed reduction group.

Fungicidal spectrum and biological properties of a new fungicide, pyriofenone.

Pyriofenone is a new fungicide developed by Ishihara Sangyo Kaisha, Ltd. To determine the fungicidal spectrum of pyriofenone, in vivo pot tests and in vitro mycelial growth-inhibition tests were conducted. Pyriofenone showed excellent activity against wheat and cucumber powdery mildew and moderate efficacy against rice blast in the pot tests. In the mycelial growth-inhibition tests, most fungi were not affected by pyriofenone except for Botrytis cinerea, Helminthosporium sacchari, Pseudocercosporella herpotrichoides, Pyricularia oryzae, Rosellinia necatrix, and Verticillium dahliae. The fungicidal properties of pyriofenone on powdery mildew in cucumber and wheat were evaluated precisely. Pyriofenone exhibited excellent preventive and residual activities. It had high rainfastness in the cucumber leaves against powdery mildew. Pyriofenone also showed inhibitory activity on lesion development upon application until 2 days after inoculation, and the lesion expansion and sporulation of the cucumber powdery mildew fungus were effectively controlled. Furthermore, pyriofenone showed translaminar and vapor activities.

Subchondral fatigue fracture of the femoral head with acetabular dysplasia treated by transposition osteotomy of the acetabulum: a case report.

Introduction: Subchondral insufficiency fracture of the femoral head commonly occurs in older women with osteoporosis. However, subchondral fatigue fracture of the subchondral femoral head is rare. We present a rare case of fatigue fracture of the subchondral femoral head with acetabular dysplasia. Case Report: The patient was a 16-year-old male, height 180 cm, weight 112 kg, and body mass index 34.6 kg/m2. Continuous right hip pain appeared after club activity of table tennis a month before admission to our department. Pain was observed on deep flexion of the right hip joint. The FADIR test was positive. X-ray images showed a depressed deformity of the right femoral head loading portion. In addition, the center-edge angle was 10° on the right and 21° on the left, tear drop distance was 12 mm on the right and 8 mm on the left, and bilateral acetabular dysplasia was noted. In magnetic resonance imaging, the T1-weighted image shows low-intensity signal and the T2-weighted image shows high-intensity signal, indicating a fatigue fracture of the femoral head with subchondral depression. Thus, transposition osteotomy of the acetabulum was performed in this case. Postoperatively, the depression portion showed gradual remodeling, and the patient returned to sports after 6 months. Because this patient was highly obese with acetabular dysplasia, a large shear force was applied to the loading portion of the femoral head relative to the acetabular rim. The femoral head was repeatedly forced, resulting in a fatigue fracture. We believe that the stress applied to the depressed portion was dispersed by the transposition osteotomy of the acetabulum, resulting in remodeling. Conclusion: This is the first report of the transposition osteotomy of the acetabulum for a subchondral fatigue fracture of the femoral head with acetabular dysplasia. Thus, this may serve as a reference in the management of such rare occurrences and pave the way for further understanding of this condition.

Relationship Between Preoperative Psoas Major Muscle Quality and Forgotten Joint Score-12 in Patients After Total Hip Arthroplasty.

Background: There are limited reports on the factors affecting the Forgotten Joint Score-12 (FJS-12) in patients after total hip arthroplasty (THA). Therefore, this study aimed to determine whether the quantity and quality of the preoperative psoas muscle are related to the FJS-12 in post-THA patients. Methods: This retrospective cohort study used mailed questionnaires and medical records. Questionnaires containing the FJS-12 were mailed to 752 patients who underwent THA at our hospital between April 2015 and August 2020. The quantity and quality of the psoas major muscle were measured by computed tomography. The association between FJS-12 and the quantity and quality of the psoas major muscle was assessed by logistic regression analysis adjusted for potentially relevant factors. Results: In total, 484 patients were included in the analysis. The FJS-12 score of the analyzed subjects was 75 points. Poor psoas major muscle quality was associated with a poor group of patients scoring <50 on the FJS-12. This association was independent of the adjustment factors. However, the quantity of psoas muscle was not associated. Conclusions: The quality of the psoas major muscle is associated with FJS-12. In the rehabilitation of patients undergoing THA, focusing on the quality of the psoas major muscle may help achieve the ultimate goal.

Comparison of tibial implant positioning between symmetrical and anatomical design implants in unicompartmental knee arthroplasty for Japanese patients.

PURPOSE: In unicompartmental knee arthroplasty (UKA) procedures, maximizing the bone coverage of the tibial implant and eliminating the medial and posterior overhang would be optimal. We commonly used Physica ZUK® (ZUK), which is a symmetrical design. Alternatively, since Persona Partial Knee® (PPK) was developed in 2017 with an anatomical design to improve bone coverage, we started PPK. We hypothesized that the PPK facilitated better bone coverage than the ZUK without obvious overhangs. This study evaluated the bone coverage and the medial and posterior overhang of these differently designed tibial implants. METHODS: Seventy-nine knees from 68 patients who underwent UKA were evaluated. Cases were categorized into the ZUK (41 knees) and PPK (38 knees) groups. CT images were acquired before surgery and 1 week after surgery. We measured the tibial bone coverage, and the medial and posterior overhang by 3D software. RESULTS: The bone coverages were 103.8 ± 4.8% and 102.0 ± 3.0%, the medial overhangs were 2.2 ± 1.2 mm and 1.4 ± 1.1 mm, and the posterior overhangs were 0.6 ± 1.3 mm and 0.4 ± 1.2 mm for the ZUK and PPK groups, respectively. The bone coverage and medial overhang were significantly different between the groups, with ZUK being larger. CONCLUSION: Patients who received PPK had significantly smaller medial overhangs and better bone coverage. PPK is more likely to give better results than ZUK.

Possibility of Predicting Pelvic Inclination Following Total Hip Arthroplasty Based on the Preoperative State: Sacral Slope and Pelvic Incidence Minus Lumbar Lordosis as Predictive Factors.

Following total hip arthroplasty (THA), some patients exhibit anterior or posterior pelvic tilt (PT). This case- control study investigated whether changes to PT following THA can be preoperatively predicted. METHODS: 135 patients with hip osteoarthritis who underwent THA were assessed. The parameters measured preoperatively and one year postoperatively were lumbar lordosis (LL) based on plain X-ray and pelvic incidence (PI), PT, and sacral slope (SS), all of which were measured as pelvic morphological angles. Patients were classified into groups (A-E) based on the degree of post-THA PT, and their preoperative conditions were compared. PI minus LL was used to evaluate spinal alignment and pelvic balance. RESULTS: Overall, 33%, 30%, 21%, 13%, and 3% of the hips of patients in Groups A, B, C, D, and E were postoperatively assessed. In Groups A-E, the SS values were 34.6°±8.9°, 37.6°±8.4°, 37.9°±8.9°, 42.6°±9.5°, and 60.0°±11.1°, whereas the PI minus LL values were 2.9°±15.0°, 1.2°±13.6°, 3.6°±17.7°, 12.7°±13.1°, and -1.3°±11.7°, respectively. CONCLUSIONS: Following THA, 70% of patients experienced posterior PT. Pre-THA SS ≥45° or PI minus LL ≥15° signified marked postoperative posterior tilt and could predict postoperative PT following THA. These findings are useful for implant placement, as they can predict pelvic inclination.

Factors Associated with Surgical Field Bacterial Detection during Total Hip Arthroplasty.

Total hip arthroplasty (THA) provides relief from hip pain and improves hip function. However, periprosthetic joint infection (PJI) remains an area of concern. We examined the detection rate of bacteria from surgical fields in wound closure, along with the relationship between bacterial detection rate and type of antiseptic, surgery time, and surgeon experience for 500 patients who underwent THA at our department. The mean age at surgery was 64.3 (± 27.3) years. The bacterial detection rate was 4.6%. None of the cases revealed PJI. No significant association between the detection rate and type of antiseptic used or surgery time was observed. However, for patients treated by surgeons with < 10 years of orthopedic experience, a detection rate of 7.3% was found, while a rate of 1.3% was observed for those treated by surgeons with ≥ 10 years of orthopedic experience. This finding indicated that orthopedic experience of less than 10 years was significantly associated with an increased bacterial detection rate (chi-square test, p=0.002). The detection rate was associated with surgeon experience but not with antiseptic type or surgery time. It is possible that intraoperative handling may increase the number of bacteria in surgical fields in wound closure.

Survey of Shoulder Osteoarthritis in Patients who Underwent Total Hip Arthroplasty for Hip Osteoarthritis.

To the best of our knowledge, no previous studies have reported a relationship between osteoarthritis (OA) of the lower limbs and OA of the shoulder joints. We evaluated the correlation between shoulder OA and hip OA. We collected contrast-enhanced computed tomography (CECT) images of the shoulder joints of 159 patients with hip OA who underwent primary total hip arthroplasty (THA). The images, taken 1 week after THA to monitor venous thromboembolism (VTE), were used to examine the prevalence of shoulder OA. They were compared with those of 103 controls who underwent CECT during the same period to monitor VTE. Shoulder OA was observed in 15% of the controls and 24% of the THA patients. Although the rate was somewhat higher in the THA group, the difference was not significant. However, in the THA group, significantly more patients with bilateral hip OA (33%) had shoulder OA than those with unilateral hip OA (17%). In summary, the prevalence of shoulder OA was significantly higher in patients with bilateral hip OA. In these patients, pain and instability in the hip joints require them to use arm support to stand up or walk, putting the weight-bearing shoulder at risk of developing OA.

An Avulsion Fracture of the Lesser Trochanter of the Femur with Prodromal Symptoms in an adult: A Case Report and Review of Literature.

Introduction: An avulsion fracture of the lesser trochanter of the femur in adults is rare and should be differentiated from neoplastic lesions. We present a rare case of avulsion fracture of the lesser trochanter of the femur with prodromal symptoms in an adult. Case Report: A right-handed 40-year-old man with gradual-onset left hip joint pain resulting from baseball pitching consulted a neighborhood doctor. X-ray images did not show any obvious anomalies; however, the pain persisted. Two months after the onset of pain, he stumbled when getting into a car, and the pain worsened. He was then brought into our hospital's emergency unit, and an avulsion fracture of the lesser trochanter of the left femur was detected. Due to mild displacement (<20 mm) and no neoplastic lesions by gadolinium-enhanced magnetic resonance imaging and the technetium scintigraphy, he was managed conservatively. During the final follow-up, 1 year after the onset of symptoms, non-union of the lesser trochanteric fracture was noticed. However, there were no pain and no limited range of motion at the hip joint; therefore, he had no problems with daily activities and sports. Conclusion: The avulsion fracture of the lesser trochanter of the femur in our patient may have been caused by repeated flexion, adduction, and internal rotation of the hip joint during baseball pitching. Although bone union was not achieved, his condition was managed successfully using conservative treatment. Our experience offers a few key learning points to manage such rare fracture occurrences in adults and suggests that conservative treatment is often sufficient for mild displacement (<20 mm) of the fracture.