Bone mineral density changes around the stem correlate with stress changes after total hip arthroplasty: A study using thermoelastic stress analysis.

Purpose: Thermoelastic stress analysis (TSA) was used to evaluate stress changes over the entire surface of a specimen. This study aimed to assess the relationship between femoral stress distribution, analysed using TSA and changes in bone mineral density (BMD) after total hip arthroplasty (THA). Methods: Stress changes in the simulated bone before and after taper-wedge stem insertion were measured using the TSA. Stress changes were compared with BMD changes around the stem 1 year after surgery in a THA patient (58 hips) with the same taper-wedge stem. Subsequently, we compared the correlation between stress changes and BMD changes. Results: TSA revealed significant stress changes before and after stem insertion, with prominent alterations in the proximal medial region. The BMD changes at 1 year post-THA exhibited a 15%-25% decrease in the proximal zones, while Zones 2-6 showed a -6% to 3% change. Notably, a strong positive correlation (0.886) was found between the stress change rate and BMD change rate. Conclusions: This study demonstrated a high correlation between femoral stress distribution assessed using TSA and subsequent BMD changes after THA. The TSA method offers the potential to predict stress distribution and BMD alterations postsurgery, aiding in implant development and clinical assessment. Combining TSA with finite element analysis could provide even more detailed insights into stress distribution. Level of Evidence: Case series (with or without comparison).

The association between variations in the number of thoracic and lumbar vertebrae and rib morphology in adolescent idiopathic scoliosis.

PURPOSE: Preoperative counting of thoracic and lumbar vertebrae is crucial in adolescent idiopathic scoliosis (AIS) due to reported anatomical variations and potential surgical site misidentification. This study investigated characteristics associated with the vertebral number variations AIS, particularly focusing on rib morphology. METHODS: Based on three-dimensional computed tomography, patients were categorized into the non-variant number group, comprising individuals with 12 thoracic and 5 lumbar vertebrae, and the variant number group, comprising individuals with different numbers of vertebrae. Additionally, the most caudal rib morphology was classified as normal, unilateral, or hypoplastic. RESULTS: A total of 359 patients were included in our study (41 males, 318 females, age: 16.3 ± 3.1 years), with 44 patients (12.3%) assigned to the variant number group. Logistic regression analysis identified unilateral ribs (odds ratio [OR]: 10.50) and lumbosacral transitional vertebrae (LSTV) (OR 6.49) as significant risk factors associated with variations. Further analysis revealed hypoplastic ribs as a significant risk factor associated with LSTV (OR: 4.58). 8 CONCLUSION: Our study suggests that abnormal rib morphology may be associated with vertebral number variations. Close attention to rib morphology is, therefore, warranted in cases with atypical vertebral numbers. Accordingly, to ensure surgical safety and accuracy, spine surgeons must communicate these variations to the surgical team, standardize nomenclature for describing them, and intraoperatively verify fusion levels with them.

Safety and feasibility of in-hospital autonomous transportation using a driverless mobility for patients with musculoskeletal disorders: preliminary clinical study to achieve mobility as a service in medical care.

BACKGROUND: Recent advancements in and the proliferation of autonomous mobility technology, such as intelligent wheelchairs, have made it possible to provide mobility services for patients with reduced mobility due to musculoskeletal disorders. In the present study, we conducted a preliminary clinical study to assess the safety and feasibility of in-hospital autonomous transportation using a driverless mobility (wheelchair) for patients with musculoskeletal disorders. METHODS: From January to February 2022, 51 patients with musculoskeletal disorders exhibiting gait disturbance who presented to our institution were included in the present study. Driverless mobility rides were conducted over a straight-line distance of 100 m from the orthopaedic outpatient reception to the payment counter after the outpatient consultation. We assessed the quality of life using an EQ-5D-5 L index and pain using a VAS score before riding the mobility to investigate the patient's condition. After the ride, a questionnaire survey was conducted to assess patient satisfaction on a 5-point scale. In addition, adverse events during the mobility ride were investigated. RESULTS: Overall satisfaction levels showed that 44 out of 51 (86%) patients rated the level as 3 or higher. There were no significant differences in the level of satisfaction based on the cause of disorders or EQ-5D-5 L Index. Among 19 patients who rated the level of satisfaction as 2-3, the ratio of postoperative patients and those with pain tended to be higher (p < 0.05). While 26 of 51 (51%) patients reported moments of feeling unsafe during the mobility ride, no actual adverse events, such as collisions, were observed. CONCLUSIONS: An in-hospital autonomous transportation service using a driverless mobility for patients with musculoskeletal disorders demonstrated high satisfaction levels and was safe with no severe adverse events observed. The expansion of autonomous mobility deployment is expected to achieve mobility as a service in medical care.

Developing a Novel Prosthetic Hand with Wireless Wearable Sensor Technology Based on User Perspectives: A Pilot Study.

Myoelectric hands are beneficial tools in the daily activities of people with upper-limb deficiencies. Because traditional myoelectric hands rely on detecting muscle activity in residual limbs, they are not suitable for individuals with short stumps or paralyzed limbs. Therefore, we developed a novel electric prosthetic hand that functions without myoelectricity, utilizing wearable wireless sensor technology for control. As a preliminary evaluation, our prototype hand with wireless button sensors was compared with a conventional myoelectric hand (Ottobock). Ten healthy therapists were enrolled in this study. The hands were fixed to their forearms, myoelectric hand muscle activity sensors were attached to the wrist extensor and flexor muscles, and wireless button sensors for the prostheses were attached to each user's trunk. Clinical evaluations were performed using the Simple Test for Evaluating Hand Function and the Action Research Arm Test. The fatigue degree was evaluated using the modified Borg scale before and after the tests. While no statistically significant differences were observed between the two hands across the tests, the change in the Borg scale was notably smaller for our prosthetic hand (p = 0.045). Compared with the Ottobock hand, the proposed hand prosthesis has potential for widespread applications in people with upper-limb deficiencies.

Varus knee osteoarthritis with ankle osteoarthritis demonstrates greater hindfoot inversion and larger ankle inversion loading during gait following total knee arthroplasty compared to varus knee osteoarthritis alone.

PURPOSE: Although patients with varus knee osteoarthritis (KOA) and concurrent ankle osteoarthritis (AOA) may experience increased ankle joint pain after total knee arthroplasty (TKA), the underlying mechanism remains unclear. This study aimed to investigate the effects of concurrent AOA on ankle and hindfoot alignment, frontal plane ankle and hindfoot biomechanics during gait following TKA and the clinical outcomes. METHODS: Twenty-four patients with varus KOA who underwent TKA were included in this retrospective cohort study. Patients were categorized into two groups: with and without AOA. Radiographic evaluations of lower-limb, ankle and hindfoot alignment, and knee and ankle clinical outcomes were conducted preoperatively and 6 months postoperatively. In addition, gait analyses were performed to investigate knee, ankle and hindfoot kinematics and kinetics. Each data was compared between patients with and without AOA. RESULTS: Concomitant AOA was found in eight ankles. The AOA group exhibited greater postoperative hindfoot varus and increased postoperative ankle pain than the non-AOA group. Gait analysis showed no significant differences in knee varus alignment or tibial tilt after TKA between the groups. However, the AOA group demonstrated significantly greater hindfoot inversion and larger ankle inversion loading. CONCLUSION: One third of patients who underwent TKA had concurrent AOA associated with hindfoot varus. Despite achieving proper coronal knee alignment postoperatively, these patients experienced greater hindfoot and ankle joint inversion load during gait. Surgeons should consider the inability to evert the hindfoot and the possibility of increased ankle joint pain when planning and performing TKA. LEVEL OF EVIDENCE: Level III.

A Novel Evaluation for Vertebral Artery Course Using 3D Magnetic Resonance Imaging with Computed Tomography -like Bone Contrast and Magnetic Resonance Angiography: A Proof of Concept Study.

OBJECTIVE: Vertebral artery (VA) injury poses a significant risk in cervical spine surgery, necessitating accurate preoperative assessment. This study aims to introduce and validate a novel approach that combines the Fast field echo that resembles a computed tomography using restricted echo spacing (FRACTURE) sequence with Time of Flight (TOF) Magnetic Resonance Angiography (MRA) for comprehensive evaluation of VA courses in the cervical spine. MATERIALS AND METHODS: A total of eight healthy volunteers and two patients participated in this study. The FRACTURE sequence provided high-resolution bone images of the cervical spine, while TOF MRA offered non-invasive vascular imaging. Fusion images were created by merging FRACTURE and MRA modalities to simultaneously visualize cervical spine structures and VA courses. Board-certified orthopedic spine surgeons independently evaluated images to assess the visibility of anatomical characteristics of the VA course by Likert-scale. RESULTS: The FRACTURE-MRA fusion images effectively depicted the extraosseous course of the VA at the craniovertebral junction, the intraosseous course of the VA at the craniovertebral junction, the VA entrance level to the transverse foramen, and the side-to-side asymmetry of bilateral VAs. Additionally, clinical cases demonstrated the utility of the proposed technique in identifying anomalies and guiding surgical interventions. CONCLUSIONS: The integration of the FRACTURE sequence and TOF MRA presents a promising methodology for the precise evaluation of VA courses in the cervical spine. This approach improves preoperative planning for cervical spine surgery with detailed anatomy and is a valuable alternative to conventional methods without contrast agents.

Retroperitoneal abscess associated with closed pelvic ring fracture diagnosed by fine free air on initial trauma pan computed tomography scan.

The patient was a 49-year-old male. He had a closed fracture of the pelvic ring that was treated successfully by avoiding anterior pelvic ring stabilization because of the presence of microscopic free air in the retroperitoneal space behind the pubic bone on initial whole-body trauma computed tomography scan. For his pelvic ring injury, transiliac rod and screw fixation was performed without the need for a pubic symphysis plate by developing the retroperitoneal space. His retroperitoneal abscess was treated by minimally invasive treatment of retroperitoneal abscess with computed tomography-guided percutaneous drainage. At 2 years postoperatively, there was no fever or elevated inflammatory response suspicious of retroperitoneal abscess recurrence. In this case, the presence of microscopic free air influenced the choice of treatment. Even in closed pelvic ring fractures, the presence of free air should be carefully considered when reading images.

Measurement of Postoperative Apical Vertebral Rotation Using Radiographic Images in Adolescent Idiopathic Scoliosis-Quantitative Evaluation Using Inverse Trigonometric Functions.

Introduction: Conventional methods for analyzing vertebral rotation are limited to postoperative patients who underwent posterior fusion. A previous methodology calculated vertebral rotation using inverse trigonometric functions based on the length of the pedicle screw (PS). Accordingly, this study evaluates rotational deformity in patients with postoperative adolescent idiopathic scoliosis (AIS) using inverse trigonometric functions. Methods: This retrospective single-center study includes patients with AIS who underwent posterior fusion surgery. Postoperative radiography and computed tomography (CT) scans were retrospectively evaluated. The magnification ratio was calculated using the rod diameter (δ=lateral/frontal rod diameter), and the visible screw lengths were measured using radiographs. The rotation angle was calculated using the apex of the main curve and the lower instrumented vertebra (LIV) (rotation angle=tan-1 (lateral PS length/(δ×frontal PS length))) immediately following the surgery as well as two and five years postoperatively. The correlation between the direct CT measurement and postoperative rotation angle progression was investigated. The crankshaft phenomenon (CSP) and distal adding-on (DAO) were evaluated as postoperative deformities. CSP was defined as a 5° increase in rotation angle. Results: Seventy-eight patients (age: 15.3±2.0 years, eight boys and seventy girls) were included. The rotation angle was strongly correlated with CT rotation measurements (r=0.87). The mean rotation angle at the apex and LIV did not change within five years postoperatively (mean: 0.5±3.6° and 0.4±3.4°, respectively). CSP and DAO were observed in 6.4% and 3.8% of patients, respectively. Conclusions: The inverse trigonometric method is useful to quantitatively evaluate the postoperative rotation angle and identify CSP.

The Optimal Patient Position on the Surgical Table for Lateral Lumbar Interbody Fusion in Adult Spinal Deformity Using Three-Dimensional Computed Tomography: A Retrospective Study.

Introduction: Lateral lumbar interbody fusion (LLIF) techniques have been extensively used in adult spinal deformity surgery. Preoperative knowledge of the optimal position of the patient on the surgical table is essential for a safe procedure. Therefore, this study aims to determine the optimal angle for positioning the patient on the surgical table during LLIF using three-dimensional computed tomography (3DCT). Methods: Data from 59 patients (2 males, 57 females, mean age 66.3±8.6 years) with adult spinal deformities treated by performing corrective spinal surgery were included in this observational retrospective study. Simulated fluoroscopic images were obtained using 3DCT images rotated from the reference position with the spinous process of S1 as the midline to the position with the spinous process in the center of the bilateral pedicle of T12-L5. The rotation angle of each vertebra was measured and defined as the optimal rotation angle (ORA). The angle that bisected the angle between the maximum and minimum ORA was defined as the optimal mean angle of the maximum and minimum ORA (OMA) and considered the optimal angle for the patient's position on the surgical table, as this position could minimize the rotation angle of the surgical table during surgery. A multiple regression analysis was performed to predict OMA. Results: Multiple regression analysis revealed the following equation: OMA=1.959+(0.238×lumbar coronal Cobb angle)+(-0.208×sagittal vertical axis). Conclusions: When the patient is placed on the surgical table by rotating them at the OMA, the rotation of the surgical table can be reduced, ensuring a safe and efficient surgical procedure.

Factors Influencing Optimal Bracing Compliance in Adolescent Idiopathic Scoliosis: A Single Center Prospective Cohort Study.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To identify factors contributing to optimal bracing compliance in adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: Poor brace compliance is a key factor affecting brace treatment success in AIS. Predictive factors influencing optimal brace compliance to achieve brace treatment success remain unknown. MATERIALS AND METHODS: This study included AIS patients, aged 10-15, with a Cobb angle of 20-40 degrees. Demographics data, radiographic assessments, and patient-reported outcomes (including the SRS-22r patient questionnaire) were collected. Brace compliance was monitored using in-brace thermometers, defining optimal bracing time as more than 18 hours/day. Multivariable logistic regression analysis was employed to identify predictors of optimal bracing time from the demographic and patient- reported outcomes score before bracing. RESULTS: Among 122 patients, 59.0% achieved optimal bracing time by six months. The achieved group indicated higher scores in satisfaction domain before bracing (3.3±0.7 vs. 3.1±0.6; P=0.034). Multivariable logistic regression analysis demonstrated that Satisfaction domain before bracing was an independent factor associated with achievement of the optimal bracing time (OR 1.97 [95%CI 1.00 - 3.89], P=0.049). The model with bracing at 1-month follow-up also demonstrated the bracing at 1-month was a significant factor (OR 1.52 [95%CI 1.30 - 1.79], P<0.001). CONCLUSION: Optimal bracing compliance in AIS is significantly influenced by pre-bracing satisfaction and brace compliance at earlier time point. These findings highlight the need to address psychological factors and early compliance in AIS bracing treatment. SRS-22r can be useful to identify the need for psychological support.

Characteristics of Lumbar Spondylolysis in Adolescent Baseball Players: Relationship between the Laterality of Lumbar Spondylolysis and the Throwing or Batting Side.

STUDY DESIGN: A retrospective, cross-sectional study was conducted to analyze the implications of asymmetric baseball movements on the incidence of spondylolysis. PURPOSE: This study aimed to evaluate the relationship between asymmetric movements and the laterality of spondylolysis. OVERVIEW OF LITERATURE: Baseball, characterized by its asymmetric throwing and batting, may disproportionately stress one side. Lumbar spondylolysis is a frequent cause of lower back pain in young athletes, particularly those involved in activities with consistent unilateral rotations such as baseball. However, whether a link exists between the laterality in spondylolysis and the dominant throwing/ batting side or whether disparities exist between pitchers and fielders remains unclear. 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.

Synovial Folds Impingement After Unicondylar Knee Arthroplasty.

Soft tissue impingement after total knee arthroplasty has been reported; however, complications after unicondylar knee arthroplasty (UKA) have rarely been reported. We report a rare case of synovial fold impingement that occurred after UKA and caused severe pain with clicking during knee flexion and extension. Diagnostic arthroscopy was performed 3 weeks after UKA and found that a hypertrophied and congested synovial fold in the medial compartment impinged on the femoral component during knee flexion and extension. After excising the synovial fold, the patient's symptoms improved. Synovial fold impingement is a complication that should be considered when patients complain of severe pain with clicking in the knee after UKA.

[Results of Watch and Wait after Chemoradiotherapy for Locally Advanced Rectal Cancer].

BACKGROUND: Watch and wait(W & W)for rectal cancer after chemoradiotherapy(CRT)is attracting attention. PURPOSE: To examine regimens and indications from the results of follow-up of cases undergoing W & W in our department. MATERIALS AND METHODS: CRT(SOX therapy 2-5 cycles, 45 Gy)was performed on patients with lower rectal cancer over a period of 2016 to 2020, and 7 patients with clinical complete response(cCR)were followed up. RESULTS: With a median follow-up of 33 months(10-74), 4 of 7 patients(57.1%)remained in cCR. Two patients had local relapse more than a year after the start of treatment, were able to undergo salvage surgery, and are alive after surgery. Patients with lateral lymph node metastasis before CRT had para-aortic lymph node metastasis at 8 months. CONCLUSIONS: Patients with maintained cCR were those with localized, node-negative disease. On the other hand, in patients with lymph node metastasis, including lateral metastasis, it was not possible to perform salvage surgery due to distant metastasis. Careful case selection and follow-up are necessary in the future.

Bisphosphonate-Related Atypical Femoral Fractures in Patients with Autoimmune Disease Treated with Glucocorticoids: Surgical Results for 20 Limbs.

BACKGROUND: Glucocorticoids induce osteoporosis, while bisphosphonates treat it, yet both can lead to atypical femoral fractures. Patients on both agents may face challenges in healing from such fractures due to their pathophysiology and pharmacological effects. METHODS: Intramedullary nail surgery was performed on 20 limbs in 19 patients with atypical femoral fractures and autoimmune diseases, who had received bisphosphonates for GC-induced osteoporosis. The average durations of glucocorticoid and bisphosphonate use were 17 and 9 years (standard deviation: 7.59 and 4.35), respectively, and the mean follow-up period was 66 months. Fifteen and five limbs were fractured at the subtrochanter and diaphysis, respectively. The surgical techniques (type of nail) and additional procedures performed in these cases were examined. The post-operative alignment and reduction status on radiographs were examined to determine their relationship with post-operative outcomes. RESULTS: Cephalomedullary long nails were inserted in nine limbs and antegrade intramedullary nails in 11 limbs. As an additional surgical procedure, open reduction, bone grafting and drilling were carried out on six, two, and five limbs, respectively. Regarding malalignment on radiographs, AP images showed varus in four limbs, and lateral images showed extension in two limbs. Regarding the cortical discontinuity, the distal fragment of the 11th limb shifted posteriorly in the lateral view. Gaps at the fracture sites were observed in 11 limbs. As a result, bone union was confirmed in 13 limbs. Five of the seven nonunion limbs required additional surgery. When comparing union and nonunion, open reduction and drilling were involved in nonunion limbs. CONCLUSION: The surgical outcomes of atypical femoral fractures in patients with autoimmune disease and on long-term glucocorticoids and bisphosphonates were poor. Although it is not possible to affirm for sure based on these results alone, management with prophylactic surgery before complete fracture is considered to be required to improve outcomes.

Association of Pars Defect Type with Clinical Outcome after Smiley Face Rod Methods for Terminal-Stage Spondylolysis.

Introduction: The smiley face rod method is an effective treatment for symptomatic terminal-stage spondylolysis. However, the risk factors for treatment failure are unknown. We investigated the association of pars defect type with the treatment outcomes of this method. Methods: We retrospectively examined data from 34 patients (18.0±6.7 years) with terminal-stage spondylolysis who underwent surgery using the smiley face rod method. The mean follow-up period was 44.9±21.4 months. The patients were divided into 2 groups: pars defect without bone atrophy or sclerosis (group A; 18 patients), and with bone atrophy and sclerosis (group B; 16 patients). We evaluated and compared the visual analog scale (VAS) score for back pain, bone union rate, and time to return to preinjury athletics level between the groups. Fisher exact and paired t tests were used to compare the variables between groups. The VAS score between the groups was compared using a 2-factor repeated-measures analysis of variance. Results: Within groups, the VAS score was significantly different over time (p<0.001). The VAS scores between groups were not significantly different. Patients in group A had a significantly higher bone union rate per pars at 6 months (group A, 65.7%; and group B, 37.5%, p=0.028) and 24 months after surgery (group A, 97.1%; and group B, 75.0%, p=0.011). All patients returned to their respective sports, and no significant differences were observed in the time to return to preinjury athletics level between the groups (p=0.055). Conclusions: The type of pars defect are associated with bone union after the smiley face rod method, but have little effect on postoperative symptoms.

The Effect of Axial Traction MRI on the Articular Cartilage Visibility in Thumb Carpometacarpal Arthritis.

OBJECTIVES: Thumb carpometacarpal arthritis has a high incidence. However, the degree of damage to the cartilage has not been accurately assessed. The purpose of this study was to examine the effects of axial traction of the thumb carpometacarpal joint during magnetic resonance imaging (MRI) on the visibility of articular cartilage in patients with thumb carpometacarpal arthritis and to evaluate the articular cartilage defect using MRI findings. MATERIALS AND METHODS: Forty-four patients with thumb carpometacarpal arthritis (14 males, 30 females) and a mean age of 67.3±8.6 years were classified according to Eaton Stages 1, 2, 3, and 4 in 2, 14, 24, and 4 patients, respectively. Axial traction MRI was performed with and without traction (3 kg) using 3-Tesla MRI (Siemens Magnetom Skyra) with a 3D T2* multiecho data imaging combination. The effectiveness of traction was verified using the joint space width before and after traction at five points (central, volar, dorsal, radial, and ulnar margins) and the original articular cartilage outline visibility classification (poor, intermediate, complete). The rate of remaining cartilage on each joint surface was also evaluated. Statistical significance was set at p<0.05 in this study. RESULTS: Joint space width increased significantly at all points with traction (P<0.01). The grade of articular cartilage outline visibility significantly improved from seven intermediate and 37 poor cases to 15 complete, 23 intermediate, and six poor cases (P<0.01). Significantly more articular cartilage remained in Stages 1-2 compared with Stages 3-4 arthritis of both articular surfaces (P<0.01 in first metacarpal, P=0.01 in trapezium). CONCLUSION: Axial traction of the thumb increased the joint space width and improved articular cartilage visibility in the thumb carpometacarpal joint. Our results suggested that axial traction MRI can be used for noninvasive evaluation of articular cartilage defects in patients with thumb carpometacarpal arthritis and aid in selecting the optimal surgical procedure.

Optimal Limb Position for the Stress Ultrasound Evaluation of Elbow Valgus Laxity in Baseball Players.

Background: The optimal limb position during stress ultrasound (SUS) evaluation of elbow valgus laxity has not been standardized. Purpose: To compare 2 elbow positions (at 90° and 30° of flexion) and report which position method better represents the increased valgus laxity characteristics of baseball players. Study Design: Controlled laboratory study. Methods: Eighteen college baseball players with no history of elbow pain or elbow disorders who belonged to a college baseball club between April and November 2021 participated in this study. The medial elbow joint space (MEJS) was recorded by ultrasonography at rest and under valgus stress, and the difference in MEJS between the conditions was considered the valgus laxity. For all participants, the MEJS was recorded at 90° and 30° of elbow flexion. In the 90° of flexion position, the participant was positioned in the supine position with abduction and external rotation of the shoulder, and 2.5 kgf of valgus stress was applied proximally to the wrist. In the 30° of flexion position, the participant was positioned in the sitting position with abduction and external rotation of the shoulder, and 3.0 kgf of valgus stress was applied to the ulnar head. Valgus laxity on the throwing and nonthrowing sides was compared between the 2 elbow positions using paired t tests or Wilcoxon signed-rank tests after checking the normality. Results: There was a significant difference in valgus laxity on the throwing side between the 90° and 30° of flexion positions (1.9 vs 1.1 mm, respectively; P = .002), whereas no significant difference between positions was seen on the nonthrowing side (P = .06). Conclusion: SUS with the elbow flexed at 90° more clearly detected valgus laxity in the study participants than the 30° of flexion position. Clinical Relevance: The quantitative evaluation of valgus laxity is important for baseball players to assess the risk of ulnar collateral ligament injury.

Correlation between preoperative CT scan of the paraspinal, psoas, and gluteus muscles and postoperative ambulatory status in patients with femoral neck fractures.

BACKGROUND: This study aimed to investigate the relationship between femoral neck fractures and sarcopenia. METHODS: This was a retrospective analysis of 92 patients with femoral neck fractures, from September 2017 to March 2020, who were classified into high ambulatory status (HG) and low ambulatory status (LG) groups. Ambulatory status was assessed before surgery, one week after surgery, at discharge, and during the final follow-up. To evaluate sarcopenia, muscle mass and fatty degeneration of the muscles were measured using preoperative CT. An axial slice of the superior end of the L5 vertebra was used to evaluate the paraspinal and psoas muscles, a slice of the superior end of the femoral head for the gluteus maximus muscle, and a slice of the inferior end of the sacroiliac joint for the gluteus medius muscle. The degeneration of the muscles was evaluated according to the Goutallier classification. RESULTS: The cross-sectional area of the gluteus medius and paraspinal muscles was significantly correlated with ambulatory status before the injury, at discharge, and during the final follow-up. CONCLUSIONS: Measurement of the gluteus medius and paraspinal muscles has the potential to evaluate sarcopenia and predict ambulatory status after femoral neck fractures.

Effect of urgent surgery within 8 hours compared to surgery between 8 and 24 hours on perioperative complications and neurological prognosis in patients older than 70 years with cervical spinal cord injury: a propensity score-matched analysis.

OBJECTIVE: This study aimed to investigate the effect of surgery within 8 hours on perioperative complications and neurological prognosis in older patients with cervical spinal cord injury by using a propensity score-matched analysis. METHODS: The authors included 87 consecutive patients older than 70 years who had cervical spinal cord injury and who had undergone posterior decompression and fusion surgery within 24 hours of injury. The patients were divided into two groups based on the time from injury to surgery: surgery within 8 hours (group 8 hours) and between 8 and 24 hours (group 8-24 hours). Following the preliminary study, the authors established a 1:1 matched model using propensity scores to adjust for baseline characteristics and neurological status on admission. Perioperative complication rates and neurological outcomes at discharge were compared between the two groups. RESULTS: Preliminary analysis of 87 prematched patients (39 in group 8 hours and 48 in group 8-24 hours) revealed that the motor index score (MIS) on admission was lower for lower extremities (12.3 ± 15.5 vs 20.0 ± 18.6, respectively; p = 0.048), and total extremities (26.7 ± 27.1 vs 40.2 ± 30.6, respectively; p = 0.035) in group 8 hours. In terms of perioperative complications, group 8 hours had significantly higher rates of cardiopulmonary dysfunction (46.2% vs 25.0%, respectively; p = 0.039). MIS improvement (the difference in scores between admission and discharge) was greater in group 8 hours for lower extremities (15.8 ± 12.6 vs 9.0 ± 10.5, respectively; p = 0.009) and total extremities (29.4 ± 21.7 vs 18.7 ± 17.7, respectively; p = 0.016). Using a 1:1 propensity score-matched analysis, 29 patient pairs from group 8 hours and group 8-24 hours were selected. There were no significant differences in baseline characteristics, neurological status on admission, and perioperative complications between the two groups, including cardiopulmonary dysfunction. Even after matching, MIS improvement was significantly greater in group 8 hours for upper extremities (13.0 ± 10.9 vs 7.8 ± 8.3, respectively; p = 0.045), lower extremities (14.8 ± 12.7 vs 8.3 ± 11.0, respectively; p = 0.044) and total extremities (27.8 ± 21.0 vs 16.0 ± 17.5, respectively; p = 0.026). CONCLUSIONS: Results of the comparison after matching demonstrated that urgent surgery within 8 hours did not increase the perioperative complication rate and significantly improved the MIS, suggesting that surgery within 8 hours may be efficient, even in older patients.

Characteristics of lumbar spondylolysis: L5 versus non-L5.

BACKGROUND: Fifth lumbar vertebra (L5) spondylolysis has a lower bone union rate than non-L5 spondylolysis, but the reason for this is unknown. This study aimed to evaluate the differences in patient and lesion characteristics between L5 and non-L5 spondylolysis. METHODS: A total of 410 patients with lumbar spondylolysis aged 18 years or younger who were treated conservatively were enrolled. Patients and lesions were divided into L5 and non-L5 (L2-L4) spondylolysis. Factors, including sex, age, presence of spina bifida occulta, stage of the main side lesion, whether the lesion was unilateral or bilateral, presence and stage of the contralateral side lesion and treatment duration, were evaluated at the first visit and compared between the two groups. RESULTS: A total of 250 patients with 349 lesions were included. The bone union rate of L5 lesions was lower than that of non-L5 lesions (75% vs. 86%, p = 0.015). Patients with L5 spondylolysis were more likely to be male (86% vs. 66%) and younger (14.0 vs. 14.6 years) than patients with non-L5 spondylolysis. Lesions of L5 spondylolysis were more likely to be in a progressive stage (28% vs. 15%), less likely to be in a pre-lysis stage (28% vs. 43%) and more likely to be in a contralateral terminal stage (14% vs. 5.3%, p = 0.013) compared with lesions of non-L5 spondylolysis. CONCLUSIONS: L5 spondylolysis was characterised by a lower bone union rate, more males, younger age, more progressive stage and more contralateral pseudarthrosis than non-L5 spondylolysis.