Simultaneous Osteosynthesis and Distal Femoral Osteotomy in a Patient With Distal Femoral Fracture Combined With Valgus Knee Deformity: A Case Report.

Distal femoral fractures are commonly treated with osteosynthesis. However, in older patients with osteoarthritis of the knee, acute primary total knee arthroplasty (TKA) may be performed to treat these fractures. Notably, no studies have documented the use of osteosynthesis in combination with distal femoral osteotomy (DFO) for treating distal femoral fractures in patients with knee osteoarthritis. This report presents the case of a 66-year-old woman with lateral compartment osteoarthritis accompanied by severe valgus knee deformity who underwent osteosynthesis for a distal femoral fracture combined with medial closing-wedge distal femoral osteotomy (MCWDFO) to correct the knee valgus deformity. She experienced a distal femoral fracture (AO/OTA 33B1.1) of the right knee because of a fall. Before the injury, she exhibited a limp due to severe knee pain with some limitations in knee flexion. Non-weight-bearing radiographs of the entire lower extremity suggested a percentage mechanical axis (%MA) of 115%, indicating severe valgus deformity. On day nine after the injury, we performed osteosynthesis for the distal femoral fracture and conducted an MCWDFO to correct the right knee valgus deformity. After MCWDFO, the %MA was corrected to 70%. Partial weight-bearing was initiated three weeks postoperatively and progressed to full weight-bearing at six weeks. To facilitate bone healing, low-intensity pulsed ultrasound (LIPUS) was applied for three months after surgery. Bone union was successfully achieved by month five. Some medial knee pain persisted for six months after surgery; nonetheless, the patient could walk without a limp. We considered that the integration of MCWDFO with osteosynthesis could provide a treatment option for patients with distal femoral fractures and lateral compartment osteoarthritis.

Overcoming High Trabectedin Resistance of Soft-tissue Sarcoma With Recombinant Methioninase: A Potential Solution of a Recalcitrant Clinical Problem.

BACKGROUND/AIM: Drug resistance has been a recalcitrant problem for sarcoma patients for many decades. Trabectedin is a second-line chemotherapy for soft-tissue sarcoma that often leads to resistance and death of the patients. The objective of the present study was to address the issue of trabectedin-chemoresistance in HT1080 fibrosarcoma cells by combining recombinant methioninase (rMETase) with trabectedin and examining their efficacy on trabectedin-resistant fibrosarcoma cells in vitro. MATERIALS AND METHODS: Trabectedin-resistant HT1080 (TR-HT1080) cells were generated by subjecting HT1080 human fibrosarcoma cells to increasing trabectedin concentrations (3.3-8 nM). IC50 values for trabectedin and rMETase were compared for HT1080 and TR-HT1080 cells. TR-HT 1080 cells were placed into four groups to determine synergy of rMETase and trabectedin on TR-HT1080 cells: a control group with no treatment; a group treated with trabectedin (3.3 nM); a group treated with rMETase (0.75 U/ml); and a group treated with both trabectedin (3.3 nM) and rMETase (0.75 U/ml). RESULTS: The IC50 value of trabectedin- on TR-HT1080 cells was 42.9 nM, whereas the IC50 value of trabectedin on the parental HT1080 cells was 3.3 nM, indicating a 13-fold increase. The combination of rMETase (0.75 U/ml) and trabectedin (3.3 nM) was synergistic on TR-HT1080 cells resulting in an inhibition of 64.2% compared to trabectedin alone (5.7%) or rMETase alone (50.5%) (p<0.05). rMETase increased the efficacy of trabectedin 11-fold on trabectedin-resistant fibrosarcoma cells. CONCLUSION: The combined administration of trabectedin and rMETase was synergistic on the viability of TR-HT1080 cells in vitro. The combination of rMETase and trabectedin has promising clinical potential for overcoming chemo-resistance of soft-tissue sarcoma.

Recombinant Methioninase Increases Eribulin Efficacy 16-fold in Highly Eribulin-resistant HT1080 Fibrosarcoma Cells, Demonstrating Potential to Overcome the Clinical Challenge of Drug-resistant Soft-tissue Sarcoma.

BACKGROUND/AIM: A major challenge in treating soft-tissue sarcoma is the development of drug resistance. Eribulin, an anti-tubulin agent, is used as a second-line chemotherapy for patients with unresectable or metastatic soft-tissue sarcoma. However, most patients with advanced soft-tissue sarcoma are resistant to eribulin and do not survive. Recombinant methioninase (rMETase) targets the fundamental and general hallmark of cancer, methionine addiction, termed the Hoffman Effect. The present study aimed to show how much rMETase could increase the efficacy of eribulin on eribulin-resistant fibrosarcoma cells in vitro. MATERIALS AND METHODS: HT1080 human fibrosarcoma cells were exposed to step-wise increasing concentrations of eribulin from 0.15-0.4 nM to establish eribulin-resistant HT1080 (ER-HT1080). ER-HT1080 cells were cultured in vitro and divided into four groups: untreated control; eribulin treated (0.15 nM); rMETase treated (0.75 U/ml); and eribulin (0.15 nM) plus rMETase (0.75 U/ml) treated. RESULTS: The IC50 of eribulin on ER-HT1080 cells was 0.95 nM compared to the IC50 of 0.15 nM on HT1080 cells, a 6-fold increase. The IC50 of rMETase on ER-HT1080 and HT1080 was 0.87 U/ml and 0.75 U/ml, respectively. The combination of rMETase (0.75 U/ml) and eribulin (0.15 nM) was synergistic on ER-HT1080 cells resulting in an inhibition of 80.1% compared to eribulin alone (5.0%) or rMETase alone (47.1%) (p<0.05). rMETase thus increased the efficacy of eribulin 16-fold on eribulin-resistant fibrosarcoma cells. CONCLUSION: The present study showed that the combination of eribulin and rMETase can overcome high eribulin resistance of fibrosarcoma. The present results demonstrate that combining rMETase with first- or second-line therapy for soft-tissue sarcoma has the potential to overcome the intractable clinical problem of drug-resistant soft-tissue sarcoma.

Knee flexor strength at 6 months after anterior cruciate ligament reconstruction using hamstring tendon can be predicted from that at 3 months.

PURPOSE: This study aimed to identify factors influencing persistent muscle weakness in knee flexor strength after anterior cruciate ligament (ACL) reconstruction using the hamstring tendon and establish a clear cut-off value at 3 months postoperatively for the limb symmetry index (LSI) to exceed 90% at 6 months postoperatively. METHODS: One hundred forty-eight patients undergoing ACL reconstruction were included and categorised into two groups based on knee flexor strength at 6 months postoperatively: patients with LSI of 90% or greater (achieved group: n = 114) and patients with LSI less than 85% (nonachieved group: n = 34). Items with significant differences between the two groups (preoperative waiting period, LSI to body weight ratio of knee flexor and extensor strength at 3 months postoperatively and peak torque angle of knee flexor muscle) were included in the multiple logistic regression analysis. Additionally, a receiver operating characteristic curve was used to calculate the cut-off value of the LSI at 3 months postoperatively, which was required to achieve the LSI criteria for knee flexor strength 6 months postoperatively. RESULTS: Multiple logistic regression analysis extracted the preoperative waiting period and LSI for knee flexor strength at 3 months postoperatively. The cut-off value at 3 months postoperatively was 76.9% (area under the curve value, 0.82; sensitivity, 0.76; and specificity, 0.81) of the LSI. CONCLUSION: The LSI of at least 76.9% for knee flexor strength at 3 months after ACL reconstruction was an indicator for achieving the 6 months postoperatively. This is a criterion to aim for, considering the stress on the graft and the regeneration process of the semitendinosus tendon. LEVEL OF EVIDENCE: Level III.

Collagen-Type Composition in the Semitendinosus, Quadriceps, and Patellar Tendons of a 22-Year-Old Patient: A Case Report.

Graft failure is a common postoperative complication after anterior cruciate ligament (ACL) reconstruction. Recently, a theory has emerged that histological and microstructural factors of autografts may be related to graft failure. We simultaneously collected the semitendinosus tendon (ST), quadriceps tendon (QT), and patellar tendon (PT) from a 22-year-old patient to provide insights into the differences in the collagen-type composition of the three tendons in skeletally mature patients. These findings may serve as a basis for selecting autografts for ACL to reduce graft failure rates. The patient was a 22-year-old female who required the removal of artificial ligament, screws, and washers and medial patellofemoral ligament (MPFL) reconstruction with an ST autograft after two surgeries for recurrent dislocation of the left patella. The ST, QT, and PT obtained during necessary intraoperative procedures were used as samples. The tissues were processed and immunostained; this was followed by confocal microscopy. Evaluation was performed by calculating the percentage of areas positive for collagen types I and III.The percentage of type I collagen in the ST, QT, and PT groups was 88%, 85%, and 88%, respectively.The collagen-type composition was examined following simultaneous collection of the ST, QT, and PT. The results revealed no significant differences in the content of physically strong type I collagen, which supports previous findings showing that the clinical outcomes after ACL reconstruction do not vary with the autograft used.

Recombinant Methioninase Is Selectively Synergistic With Doxorubicin Against Wild-type Fibrosarcoma Cells Compared to Normal Cells and Overcomes Highly-Doxorubicin-resistant Fibrosarcoma.

BACKGROUND/AIM: Doxorubicin is first-line therapy for soft-tissue sarcoma, but patients can develop resistance which is usually fatal. As a novel therapeutic strategy, the present study aimed to determine the synergy of recombinant methioninase (rMETase) and doxorubicin against HT1080 fibrosarcoma cells compared to Hs27 normal fibroblasts, and rMETase efficacy against doxorubicin-resistant HT1080 cells in vitro. MATERIALS AND METHODS: The 50% inhibitory concentrations (IC50) of doxorubicin and rMETase, as well as their combination efficacy, against HT1080 human fibrosarcoma cells, Hs27 normal human fibroblasts and doxorubicin-resistant HT1080 (DR-HT1080) cells were determined. Dual-color HT1080 cells which expressed red fluorescent protein (RFP) in the cytoplasm and green fluorescent protein (GFP) in the nuclei were used to visualize nuclear fragmentation during treatment. Nuclear fragmentation was observed with an IX71 fluorescence microscope. RESULTS: The IC50 for doxorubicin was 3.3 µM for HT1080 cells, 12.4 µM for DR-HT1080 cells, and 7.25 µM for Hs27 cells. The IC50 for rMETase was 0.75 U/ml for HT1080 cells, 0.42 U/ml for DR-HT1080 cells, and 0.93 U/ml for Hs27 cells. The combination of rMETase and doxorubicin was synergistic against fibrosarcoma cells but not against normal fibroblasts. The combination of doxorubicin plus rMETase also caused more fragmented nuclei than either treatment alone in HT1080 cells. rMETase alone was highly effective against the DR-HT1080 cells as well as the parental HT1080 cells. CONCLUSION: The present results indicate the future clinical potential of rMETase in combination with doxorubicin for fibrosarcoma, including doxorubicin-resistant fibrosarcoma.

The Validation of the Japanese Version of the Scoliosis Research Society-30 Questionnaire for Adolescent Idiopathic Scoliosis Patients.

Introduction: The Scoliosis Research Society-30 (SRS-30) is a questionnaire originally developed from the SRS-22r questionnaire and is used to evaluate adolescent idiopathic scoliosis (AIS). It comprised questions on five domains: function, pain, self-image, mental health, and satisfaction, with seven additional questions related to postoperative aspects. In addition to the original English version, translations in multiple languages have been effectively applied. Herein, we evaluated the internal consistency and external validity of the Japanese version of the SRS-30 for AIS patients. Methods: Among the 30 questions in SRS-30, the eight additional questions from SRS-22r were translated and back-translated to create a Japanese version of the SRS-30. This translated questionnaire was then used to survey patients with AIS who underwent corrective fusion surgery one year postoperatively. The internal consistency of the responses was evaluated using the Cronbach α coefficient. Additionally, the Spearman correlation analyses were conducted to assess the correlation between the scores obtained from the SRS-30 Japanese version and SRS-22r and the Oswestry Disability Index (ODI) for the overall scale and the five domains. Results: A total of 81 cases (eight males and 73 females; mean age at surgery 14.4 years) were enrolled. The mean preoperative Cobb angle was 51.0°. The Cronbach α coefficient for the overall SRS-30 was 0.861, indicating high internal consistency, while the coefficients for each domain were as follows: function/activity, 0.697; pain, 0.405; self-image/appearance, 0.776; mental health, 0.845; and satisfaction, 0.559. The SRS-30 total score significantly correlated with the SRS-22r total (r=0.945, P<0.001) and the ODI (r=-0.511, P<0.001). The SRS-30 domains highly correlated with the corresponding SRS-22r domains, with correlations ranging from r=0.826 to 0.901 (all P<0.001). Conclusions: The Japanese version of the SRS-30 demonstrated good internal and external validity. The SRS-30 can be used as an assessment tool for health-related quality of life in AIS patients.

Combination therapy with immune checkpoint inhibitors and denosumab improves clinical outcomes in non-small cell lung cancer with bone metastases.

BACKGROUND: The concomitant use of denosumab and immune checkpoint inhibitor (ICI) treatment may have synergistic effects and enhance antitumor activity; however, this has not been fully evaluated. This study aimed to evaluate the clinical outcomes of non-small cell lung cancer (NSCLC) patients with bone metastases receiving combination therapy and to identify the best combination regimen. METHODS: Eighty-six NSCLC patients with bone metastases who received ICI treatment were enrolled in this study. The patients were divided into two groups; a denosumab combination group (D + ICI group; n = 47) and a non-combination group (non-D + ICI group; n = 39). The response rate (RR) for bone metastases, disease control rate (DCR), overall survival (OS), real world progression-free survival (rwPFS), and the incidence of immune-related adverse events (irAEs) were evaluated. Additionally, the time when denosumab treatment should commence and concomitant treatment duration were evaluated. RESULTS: The D + ICI group showed significantly better RR (40.4 % vs. 20.5 %, p = 0.01), DCR (67.3 % vs. 38.7 %, p = 0.02), OS (14.2 vs. 8.6 months, p = 0.02), and rwPFS (7.4 vs. 3.6 months, p < 0.01) than the non-D + ICI group; however, incidence of irAEs showed no difference (29.7 % vs. 12.8 %, p = 0.07). Although clinical outcomes did not differ regardless of whether denosumab was initiated before or after ICI treatment, the group that received concomitant denosumab for more than four months had significantly better RR (46.2 % vs. 17.4 %, p = 0.03), OS (20.3 vs. 3.8 months, p < 0.01), and rwPFS (10.9 vs. 2.8 months, p < 0.01) than the group that received concomitant denosumab for less than four months. However, the landmark analysis showed no significant differences in OS (20.4 vs. 12.7 months, p = 0.11) and rwPFS (22.8 vs. 11.2 months, p = 0.21), and the results of denosumab duration were influenced by long-term survivors. CONCLUSION: Denosumab showed favorable synergistic effects with ICI treatment and may significantly improve the response to bone metastasis and prognosis without increasing the incidence of irAEs.

Membrane Formed Around Liquid Nitrogen-treated Bone Promotes Osteogenesis and Revitalization in a Rat Model.

BACKGROUND/AIM: This study aimed to investigate the structure and functions of the membrane formed around liquid nitrogen-treated bones in the osteogenesis and revitalization of frozen bone using a rat model. MATERIALS AND METHODS: Segmental defects were created in femurs of rats, and resected bones treated with liquid nitrogen [frozen bone (FB) group, n=20] or polymethylmethacrylate (PMMA group; n=20) were implanted as spacers. Histological analysis and quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR) of the membrane around each spacer were performed for bone morphogenetic protein 2 (BMP2), transforming growth factor (TGF)-ß1, and vascular endothelial growth factor (VEGF). Furthermore, in week 2, spacers were removed from both groups (n=5 each), and autologous cancellous bone (ACB) harvested from the ilium was grafted into the defect. Radiological analysis was performed until bone union was observed. RESULTS: In week 2, similar two-layered membrane structures were observed in both groups; these matured into fibrous tissues over time. At each evaluation point, qRT-PCR showed higher expression of all factors in the FB than in the PMMA group. In the ACB graft model, the mean period to bone union and new bone volume were significantly shorter and greater, respectively, in the FB. Chondrocytes invaded the osteotomy site from the membrane in the FB, suggesting that endochondral ossification may occur and be related to osteogenesis. Additionally, fibroblasts and capillaries in the membrane invaded the surface of treated bone in week 2, and osteocytes were observed around them in weeks 6 and 8. CONCLUSION: Fibrous membranous tissue formed around liquid nitrogen-treated bones may be vital for osteogenesis and revitalization of frozen bones.

Pathology, Diagnosis, and Management of Sarcoma.

Due to the rarity and heterogeneity of sarcoma, investigation into molecular targets and new treatments has been particularly challenging [...].

Identifying unstable ramp lesions using ultrasonography.

BACKGROUND: Patients with suspected ramp lesions on magnetic resonance imaging (MRI) or ultrasonography (US) healed and showed no instability based on intraoperative arthroscopic findings. The purpose of this study was to assess the use of US in evaluating ramp lesions preoperatively and intraoperatively. METHODS: Eighty-two knees that underwent anterior cruciate ligament (ACL) reconstruction between January 2022 and June 2023 were included to assess the ramp lesion complication rate and instability using arthroscopic findings. The detection rate of ramp lesions using US at the initial visit and preoperatively was also investigated. The test-retest reliability was assessed using the intraclass correlation coefficient and analyzed using two-way random effects and absolute agreement. The patients were divided into two groups based on the presence or absence of ramp lesions, and these data were compared using Student's t-test. Statistical significance was set at p < 0.05. RESULTS: On ultrasound examination, 90.0% of the cases had a ramp lesion at the initial examination, of which 22.2% were poorly delineated on the day of surgery. In the cases where the ramp lesion was unstable at the time of surgery, it could be delineated using US. In the cases where the ramp lesion was stable, it was difficult to delineate the lesion using US. CONCLUSIONS: Unstable ramp lesions complicating ACL injuries could be detected using US.

What are the Optimal Systemic Treatment Options for Rhabdomyosarcoma?

OPINION STATEMENT: Rhabdomyosarcoma, a soft tissue sarcoma commonly observed in childhood, requires multidisciplinary treatment, including surgical tumor resection, chemotherapy, and radiation therapy. Although long-term survival can be expected in patients with localized rhabdomyosarcoma, the clinical outcomes in patients with metastatic or unresectable rhabdomyosarcoma remain unsatisfactory. To improve the outcomes of rhabdomyosarcoma, it is important to explore effective systemic treatments for metastatic rhabdomyosarcoma. Currently, multiagent chemotherapy comprising vincristine, actinomycin D, and ifosfamide/cyclophosphamide remains standard systemic treatment for rhabdomyosarcoma. On the other hand, new treatment, such as immune checkpoint inhibitors and molecular targeted drugs, have demonstrated superior clinical outcomes compared to those of standard treatments in various type of malignancies. Therefore, it is necessary to assess the efficacies of these treatments in patients with rhabdomyosarcoma. Recent clinical studies have shown efficacies and safeties of temozolomide combined with vincristine/irinotecan, olaratumab combined with doxorubicin or vincristine/irinotecan, and long-term maintenance therapy. Furthermore, basic researches demonstrated new therapeutic targets. Future studies using these approaches are required to assess their clinical significances.

Combining dynamics of serum inflammatory and nutritional indicators as novel biomarkers in immune checkpoint inhibitor treatment of non-small-cell lung cancer with bone metastases.

OBJECTIVES: We aimed to investigate the association of the dynamics of serum inflammatory and nutritional indicators with immune checkpoint inhibitor (ICI) response in non-small-cell lung cancer (NSCLC) with bone metastases, and to develop a novel predictive scoring system based on these indicators. METHODS: Patients with NSCLC having bone metastases treated with ICIs were categorized as: the development cohort (January 2016 to March 2021, n = 60) and the validation cohort (April 2021 to June 2023, n = 40). Serum indicators of inflammation and nutrition such as C-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), albumin, prognostic nutritional index (PNI) were investigated before and six weeks after ICI initiation. The correlations of these dynamics with bone metastasis response rate (BoMRR) and overall survival (OS) were analyzed. A scoring system consisting of independent predictors was developed (IMMUNO-SCORE) and correlations with clinical outcomes were validated using the validation cohort. RESULTS: In the development cohort, multivariable analysis showed that NLR and PNI dynamics and CRP, NLR, and PNI dynamics were independent predictors of BoMRR and OS, respectively. The IMMUNO-SCORE consisting of NLR and PNI dynamics, which were the common predictors of the clinical outcomes, was significantly correlated with BoMRR (p < 0.01) and OS (p < 0.001) in cross-validation. The area under the curve of the score (0.786) was higher than individual NLR and PNI dynamics (0.72 and 0.684). CONCLUSION: Dynamics in NLR and PNI were demonstrated as biomarkers of treatment response and prognosis in ICI treatment of NSCLC with bone metastases, and the score combining these biomarkers was significantly correlated with clinical outcomes.

DNA-Binding Agent Trabectedin Combined With Recombinant Methioninase Is Synergistic to Decrease Fibrosarcoma Cell Viability and Induce Nuclear Fragmentation But Not Synergistic on Normal Fibroblasts.

BACKGROUND/AIM: The alkylating agent trabectedin, which binds the minor groove of DNA, is second-line therapy for soft-tissue sarcoma but has only moderate efficacy. The aim of the present study was to determine the synergistic efficacy of recombinant methioninase (rMETase) and trabectedin on fibrosarcoma cells in vitro, compared with normal fibroblasts. MATERIALS AND METHODS: HT1080 human fibrosarcoma cells expressing green fluorescent protein (GFP) in the nucleus and red fluorescent protein (RFP) in the cytoplasm and Hs27 normal human fibroblasts, were used. Each cell line was cultured in vitro and divided into four groups: no-treatment control; trabectedin treated; rMETase treated; and trabectedin plus rMETase treated. The dual-color HT1080 cells were used to quantitate nuclear fragmentation in each treatment group. RESULTS: The combination of rMETase and trabectedin was highly synergistic to decrease HT1080 cell viability. In contrast, there was no synergy on Hs27 cells. Moreover, nuclear fragmentation occurred synergistically with the combination of trabectedin and rMETase on dual-color HT1080 cells. CONCLUSION: The combination treatment of trabectedin plus rMETase was highly synergistic on fibrosarcoma cells in vitro suggesting that the combination can improve the outcome of trabectedin alone in future clinical studies. The lack of synergy of rMETase and trabectedin on normal fibroblasts suggests the combination is not toxic to normal cells. Synergy of the two drugs may be due to the high rate of nuclear fragmentation on treated HT1080 cells, and the late-S/G2 cell-cycle block of cancer cells by rMETase, which is a target for trabectedin. The results of the present study suggest the future clinical potential of the combination of rMETase and trabectedin for soft-tissue sarcoma.

Evaluation of crankshaft phenomenon after posterior fusion for early onset scoliosis using an inverse trigonometric function: a multicenter retrospective cohort study.

PURPOSE: The crankshaft phenomenon (CSP) is a corrective loss after posterior surgery for early onset scoliosis (EOS). However, an accurate method for CSP evaluation has yet to be developed. In this study, we evaluated pedicle screw (PS) length and rotation angle using an inverse trigonometric function and investigated the prevalence of the CSP. METHODS: Fifty patients from nine institutions (mean age 10.6 years, male/female ratio 4:46) who underwent early definitive fusion surgery at ≤ 11 years of age were included. The rotation angle was calculated as arctan (lateral/frontal PS length) using radiography. Measurements were taken at the apex and lower instrumented vertebra (LIV) immediate, 2-, and 5-year postoperatively. CSP was defined as a rotation angle progression ≥ 5°. We divided patients into CSP and non-CSP groups and measured the demographic parameters, Risser grade, state of the triradiate cartilage, major coronal Cobb angle, T1-T12 length, T1-S1 length, and presence of distal adding-on (DAO). We compared these variables between groups and investigated the correlation between the measured variables and vertebral rotation. Logistic regression analysis investigated factors associated with CSP. RESULTS: The rotation angle progressed by 2.4 and 1.3° over 5 years for the apex and LIV, respectively. CSP occurred in 15 cases (30%), DAO in 11 cases (22%), and CSP and DAO overlapped in 4 cases (8%). In the CSP group, the T1-T12 length was low immediate postoperatively. The rotation angle was negatively correlated with preoperative height (r = - 0.33), T1-T12 length (r = - 0.35), and T1-S1 length (r = - 0.30). A lower preoperative T1-T12 length was associated with CSP (odds ratio: 0.996, p = 0.048). CONCLUSIONS: CSP occurred in 30% of patients with EOS who underwent definitive fusion. The presence of CSP was associated with a lower preoperative T1-T12 length. LEVEL OF EVIDENCE: Diagnosis, level IV.

Intraoperative Fracture during the Insertion of Advanced Locking Screws (T2 Alpha Femur Retrograde Intramedullary Nailing System): Report of Two Cases and Identifying Causes and Prevention.

Background: Recently, the T2 alpha nailing system (Stryker, Inc.), which has advanced locking screws that can attach a screw to a rod, has been used worldwide and is expected to improve fracture fixation. We analyzed two cases of supracondylar femoral fractures in older adult patients, in which intraoperative fractures occurred during the insertion of advanced locking screws of the T2 alpha femur retrograde intramedullary nail. Case presentation: A 93-year-old and an 82-year-old woman each underwent T2 alpha femur retrograde nail fixation for supracondylar femur fractures at separate hospitals, and advanced locking screws were used as the proximal transverse locking screws. In both patients, a fracture line was observed at the proximal screw postoperatively, and the fractures were refixed with distal cable wiring and/or femoral distal plates. The patients were subsequently discharged from the same facility with no remarkable pain. Conclusions: When inserting advanced locking screws, it is necessary to enlarge the screw hole in the near-bone cortex with a counterbore drill, which might add torque to the bone cortex that could result in fractures. If the sleeve is distant from the bone, the counterbore drill will not reach the bone, the screw hole will not expand, and the insertion of advanced locking screws will apply a strong torque to the bone cortex and may result in fracture. Moreover, it is important to confirm that the counterbore drill is securely inserted under fluoroscopy and to carefully enlarge the bony foramen manually to prevent fractures during screw insertion.

Evaluation of Conditions for the Development of Cryogenic Spinal Cord Injury Using a Canine Model: An Experimental Study on the Safety of Cryoablation for Metastatic Spinal Tumors.

BACKGROUND AND PURPOSE: Although the application of cryoablation to metastatic spinal tumors has been attempted, spinal cryoablation has the unique complication of cryogenic spinal cord injury. This study aimed to elucidate the conditions for the development of cryogenic spinal cord injury. MATERIALS AND METHODS: Fifteen canines were used in this study. A metal probe was inserted into the 13th thoracic vertebral body. Cryoablation was performed for 10 minutes by freezing the probe in liquid nitrogen. The control canine underwent probe insertion only. Spinal cord monitoring, epidural temperature measurement, motor function assessment, and pathologic examination of the spinal cord were performed. RESULTS: During the 10 minutes of cryoablation, the epidural temperature decreased and reached the lowest epidural temperature (LET) at the end of cryoablation. The LETs (degrees celsius [°C]) of each canine were -37, -30, -27, -8, -3, -2, 0, 1, 4, 8, 16, 18, 20, and 25, respectively. As the epidural temperature decreased, waveform amplitudes also decreased. At the end of cryoablation (10 minutes after the start of cryoablation), abnormal waves were observed in 92.9% (13/14) of canines. With epidural rewarming, the amplitude of the waveforms tended to recover. After epidural rewarming (2 hours after the start of cryoablation), abnormal waves were observed in 28.6% (4/14) of canines. The LETs (°C) of the canines with abnormal waves after epidural rewarming were -37, -30, -27, and -8. None of the canines with normal waves after epidural rewarming had any motor impairment. In contrast, all canines with remaining abnormal waves after epidural rewarming had motor impairment. In the pathologic assessment, cryogenic changes were found in canines with LETs (°C) of -37 -30, -27, -8, 0, and 1. CONCLUSIONS: This study showed that 10-minute spinal cryoablation with LETs (°C) of -37, -30, -27, -8, 0, and 1 caused cryogenic spinal cord injury. There was no evidence of cryogenic spinal cord injury in canines with LET of ≥4°C. The epidural temperature threshold for cryogenic spinal cord injury is between 1 and 4°C, suggesting that the epidural temperature should be maintained above at least 4°C to prevent cryogenic spinal cord injury.

Constitutional varus knee due to tibial deformity is common and represents a good indication for high tibial osteotomy in Japanese population: Consideration of 1010 knees.

PURPOSE: This study aimed to elucidate the characteristics of varus knee deformities in the Japanese population, prevalence of various around knee osteotomy procedures and influence of femoral and tibial bowing. METHODS: Varus knee deformity was defined as a weight-bearing line ratio of <50%. A total of 1010 varus knees were selected from 1814 varus knees with weight-bearing full-length radiographs, obtained at two facilities, based on exclusion criteria. Various parameters were measured, and around knee osteotomy simulations based on the deformity centre were conducted using digital planning tools. Bowing of the femoral and tibial shafts was measured, with bowing defined as follows: ≤ -0.6° indicating lateral bowing and ≥ 0.6° indicating medial bowing. Statistical analysis was performed to investigate age-related correlations and their impact on surgical techniques. RESULTS: The study revealed that the proximal tibia was the centre of deformity in Japanese varus knees (42.8%), and high tibial osteotomy was frequently indicated (81.6%). Age demonstrated a mild correlation with femoral shaft bowing (r = -0.29), leading to an increase in the mechanical lateral distal femoral angle and to a decrease in the hip-knee-ankle angle and weight-bearing line ratio (r = -0.29, 0.221, 0.219). The tibial shaft bowing was unaffected by age (r = -0.022). CONCLUSION: A significant proportion of Japanese individuals with varus knees exhibit a deformity centre located in the proximal tibia, making them suitable candidates for high tibial osteotomy. No age-related alterations were discerned in tibial morphology, indicating that the occurrence of constitutional varus knees is attributable to tibial deformities in the Japanese patient cohort. LEVEL OF EVIDENCE: Level IV.

Instrumentation failure following pediatric spine deformity growth-sparing surgery using traditional growing rods or vertical expandable prosthetic titanium ribs.

BACKGROUND: Instrumentation failure (IF) is a major complication associated with growth-sparing surgery for pediatric spinal deformities; however, studies focusing on IF following each surgical procedure are lacking. We aimed to evaluate the incidence, timing, and rates of unplanned return to the operating room (UPROR) associated with IF following each surgical procedure in growth-sparing surgeries using traditional growing rods (TGRs) and vertical expandable prosthetic titanium ribs (VEPTRs). METHODS: We reviewed 1,139 surgical procedures documented in a Japanese multicenter database from 2015 to 2017. Of these, 544 TGR and 455 VEPTR procedures were included for evaluation on a per-surgery basis. IF was defined as the occurrence of an implant-related complication requiring revision surgery. RESULTS: The surgery-based incidences of IF requiring revision surgery in the TGR and VEPTR groups were 4.3% and 4.0%, respectively, with no significant intergroup difference. Remarkably, there was a negative correlation between IF incidence per surgical procedure and the number of lengthening surgeries in both groups. In addition, rod breakage in the TGR group and anchor-related complications in the VEPTR group tended to occur relatively early in the treatment course. The surgery-based rates of UPROR due to IF in the TGR and VEPTR groups were 2.0% and 1.5%, respectively, showing no statistically significant difference. CONCLUSIONS: We found that IF, such as anchor related-complications and rod breakage, occurs more frequently earlier in the course of lengthening surgeries. This finding may help in patient counseling and highlights the importance of close postoperative follow-up to detect IF and improve outcomes.