Purpose: The impact of postoperative nutritional status on clinical outcomes and biomechanics following total knee arthroplasty remains largely unknown. This study aimed to assess this question using the prognostic nutritional index to evaluate the nutritional status of orthopedic participants. Methods: Patients with knee osteoarthritis who underwent total knee arthroplasty (n=49) in Japan were divided into two groups based on their 1-week postoperative prognostic nutritional index. Group L patients had a prognostic nutritional index <40, whereas Group H comprised patients with a prognostic nutritional index ≥40. Postoperative improvements in Knee Injury and Osteoarthritis Outcome Score were evaluated. The patients performed squats under single-fluoroscopic surveillance in the sagittal plane for biomechanical evaluation. A two-dimensional/three-dimensional registration technique was employed to measure the tibiofemoral kinematics. The axial rotation of the femoral component relative to the tibial component and the anteroposterior translation of the medial and lateral femorotibial contact points were measured. Results: Group H showed significantly higher pain scores than Group L at 12 and 36 months postoperatively and a significantly higher symptom score at 36 months postoperatively. The kinematic comparison revealed that the axial external rotation in Group L was larger than that in Group H from 70° to 80° with flexion. Moreover, in the medial anteroposterior translation, Group L was more anteriorly located than Group H, with flexion beyond 30°. Conclusion The results suggest that a high postoperative nutritional status significantly improved pain and other symptoms and was associated with better knee biomechanics following total knee arthroplasty.

Purpose: The impact of postoperative nutritional status on clinical outcomes and biomechanics following total knee arthroplasty remains largely unknown. This study aimed to assess this question using the prognostic nutritional index to evaluate the nutritional status of orthopedic participants. Methods: Patients with knee osteoarthritis who underwent total knee arthroplasty (n=49) in Japan were divided into two groups based on their 1-week postoperative prognostic nutritional index. Group L patients had a prognostic nutritional index <40, whereas Group H comprised patients with a prognostic nutritional index ≥40. Postoperative improvements in Knee Injury and Osteoarthritis Outcome Score were evaluated. The patients performed squats under single-fluoroscopic surveillance in the sagittal plane for biomechanical evaluation. A two-dimensional/three-dimensional registration technique was employed to measure the tibiofemoral kinematics. The axial rotation of the femoral component relative to the tibial component and the anteroposterior translation of the medial and lateral femorotibial contact points were measured. Results: Group H showed significantly higher pain scores than Group L at 12 and 36 months postoperatively and a significantly higher symptom score at 36 months postoperatively. The kinematic comparison revealed that the axial external rotation in Group L was larger than that in Group H from 70° to 80° with flexion. Moreover, in the medial anteroposterior translation, Group L was more anteriorly located than Group H, with flexion beyond 30°. Conclusion The results suggest that a high postoperative nutritional status significantly improved pain and other symptoms and was associated with better knee biomechanics following total knee arthroplasty.

Purpose: The impact of postoperative nutritional status on clinical outcomes and biomechanics following total knee arthroplasty remains largely unknown. This study aimed to assess this question using the prognostic nutritional index to evaluate the nutritional status of orthopedic participants. Methods: Patients with knee osteoarthritis who underwent total knee arthroplasty (n=49) in Japan were divided into two groups based on their 1-week postoperative prognostic nutritional index. Group L patients had a prognostic nutritional index <40, whereas Group H comprised patients with a prognostic nutritional index ≥40. Postoperative improvements in Knee Injury and Osteoarthritis Outcome Score were evaluated. The patients performed squats under single-fluoroscopic surveillance in the sagittal plane for biomechanical evaluation. A two-dimensional/three-dimensional registration technique was employed to measure the tibiofemoral kinematics. The axial rotation of the femoral component relative to the tibial component and the anteroposterior translation of the medial and lateral femorotibial contact points were measured. Results: Group H showed significantly higher pain scores than Group L at 12 and 36 months postoperatively and a significantly higher symptom score at 36 months postoperatively. The kinematic comparison revealed that the axial external rotation in Group L was larger than that in Group H from 70° to 80° with flexion. Moreover, in the medial anteroposterior translation, Group L was more anteriorly located than Group H, with flexion beyond 30°. Conclusion The results suggest that a high postoperative nutritional status significantly improved pain and other symptoms and was associated with better knee biomechanics following total knee arthroplasty.

Purpose: The impact of postoperative nutritional status on clinical outcomes and biomechanics following total knee arthroplasty remains largely unknown. This study aimed to assess this question using the prognostic nutritional index to evaluate the nutritional status of orthopedic participants. Methods: Patients with knee osteoarthritis who underwent total knee arthroplasty (n=49) in Japan were divided into two groups based on their 1-week postoperative prognostic nutritional index. Group L patients had a prognostic nutritional index <40, whereas Group H comprised patients with a prognostic nutritional index ≥40. Postoperative improvements in Knee Injury and Osteoarthritis Outcome Score were evaluated. The patients performed squats under single-fluoroscopic surveillance in the sagittal plane for biomechanical evaluation. A two-dimensional/three-dimensional registration technique was employed to measure the tibiofemoral kinematics. The axial rotation of the femoral component relative to the tibial component and the anteroposterior translation of the medial and lateral femorotibial contact points were measured. Results: Group H showed significantly higher pain scores than Group L at 12 and 36 months postoperatively and a significantly higher symptom score at 36 months postoperatively. The kinematic comparison revealed that the axial external rotation in Group L was larger than that in Group H from 70° to 80° with flexion. Moreover, in the medial anteroposterior translation, Group L was more anteriorly located than Group H, with flexion beyond 30°. Conclusion The results suggest that a high postoperative nutritional status significantly improved pain and other symptoms and was associated with better knee biomechanics following total knee arthroplasty.

Purpose: The impact of postoperative nutritional status on clinical outcomes and biomechanics following total knee arthroplasty remains largely unknown. This study aimed to assess this question using the prognostic nutritional index to evaluate the nutritional status of orthopedic participants. Methods: Patients with knee osteoarthritis who underwent total knee arthroplasty (n=49) in Japan were divided into two groups based on their 1-week postoperative prognostic nutritional index. Group L patients had a prognostic nutritional index <40, whereas Group H comprised patients with a prognostic nutritional index ≥40. Postoperative improvements in Knee Injury and Osteoarthritis Outcome Score were evaluated. The patients performed squats under single-fluoroscopic surveillance in the sagittal plane for biomechanical evaluation. A two-dimensional/three-dimensional registration technique was employed to measure the tibiofemoral kinematics. The axial rotation of the femoral component relative to the tibial component and the anteroposterior translation of the medial and lateral femorotibial contact points were measured. Results: Group H showed significantly higher pain scores than Group L at 12 and 36 months postoperatively and a significantly higher symptom score at 36 months postoperatively. The kinematic comparison revealed that the axial external rotation in Group L was larger than that in Group H from 70° to 80° with flexion. Moreover, in the medial anteroposterior translation, Group L was more anteriorly located than Group H, with flexion beyond 30°. Conclusion The results suggest that a high postoperative nutritional status significantly improved pain and other symptoms and was associated with better knee biomechanics following total knee arthroplasty.

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.

Methods: A total of 224 consecutive patients with OVFs aged ≥65 years who received treatment within 2 weeks after the occurrence of injury were enrolled. The patients were followed up for 6 months thereafter. The criteria for evaluating the degree of independence were applied to evaluate ADLs. Multivariable analysis with a logistic regression model was performed to evaluate the risk factors for ADL decline. Results: In total, 49/224 patients (21.9%) showed a decline in ADLs. Of these, 23/116 patients (19.8%) in the rest group and 26/108 patients (24.1%) in the no-rest group experienced a decline in ADLs. In the logistic regression analyses, a diffuse low signal on T2- weighted magnetic resonance imaging (MRI) (odds ratio, 5.78; 95% confidence interval, 2.09–16.0; p=0.0007) and vertebral instability (odds ratio, 3.89; 95% confidence interval, 1.32–11.4; p=0.0135) were identified as independent factors in the rest and no-rest groups, respectively. Conclusions In patients with acute OVFs, a diffuse low signal on T2-weighted MRI and severe vertebral instability were independently associated with ADL decline in patients treated with and without initial bed rest, respectively.

Methods: Fifty-three patients with 57 fresh pre-lysis-stage lesions who had completed conservative treatment were included in the study (40 men, 13 women; mean age, 14.3 years). We investigated the rate of bone healing and the relationship between bone healing after conservative therapy and factors such as age, sex, vertebral level, unilateral/bilateral lesions, and presence of spina bifida occulta. Results: The overall bone healing rate was 95% (54/57 lesions). Bilateral lesions had a significantly lower bone healing rate than unilateral lesions (86% vs. 100%, p=0.046). There were no statistically significant differences based on age, sex, vertebral level, or presence of spina bifida occulta. Conclusions The bone healing rate in unilateral lesions was 100%, which was significantly higher than that in bilateral lesions. It is important to detect and initiate treatment while the lesion is still unilateral, if possible.

Methods: We evaluated 48 patients (38 boys and 10 girls) with bilateral L5 spondylolysis diagnosed during or before high school. L5 spondylolysis was classified into two groups: fresh group (bilateral fresh spondylolysis cases), and terminal group (cases wherein one side had fresh spondylolysis and the contralateral side had terminal spondylolysis). We investigated the age of examination and bone healing rate in both groups. We investigated progressive-stage lesions and bone healing rate with or without progressive-stage lesions. Results: The bone healing rate in the fresh group was significantly higher than that in the terminal group 72.0% vs. 26.1%, p =0.003). In both the groups, the bone healing rate was significantly higher in patients without progressive-stage lesions than in those with progressive-stage lesions. Conclusions Bone healing of progressive-stage fresh spondylolysis was not achieved by conservative treatment when contralateral terminal spondylolysis was present in adolescents with bilateral L5 spondylolysis. Our results suggest that bilateral L5 spondylolysis treatment strategies must be determined based on the combination of the stages present.

Introduction: Unidirectional porous β-tricalcium phosphate (UDPTCP) consists of a novel porous artificial bone that is structurally different from conventional artificial bone comprised of spherical porous β-tricalcium phosphate (SPTCP).Case presentation: We present our first four clinical cases of opening-wedge high tibial osteotomy (OWHTO) using UDPTCP and SPTCP together. The patients’ mean age was 54.5 ± 5.9 years, and the mean observation period was 20.8 ± 2.8 months. In OWHTO, two wedge shaped pieces of UDPTCP and SPTCP were cut to fit the gap and implanted parallel to each other in the anterior and posterior parts, respectively. We evaluated the correction loss and bone remodeling for UDPTCP and SPTCP over time using radiography and computed tomography, and evaluated the clinical outcomes.Conclusion: There was no correction loss reported in any case, and early bone remodeling was observed with UDPTCP. All patients achieved satisfactory clinical results with no adverse events.