Alaska Pollock-derived Gelatin Sealant has Higher Sealing Strength than, and Comparable Biocompatibility with, Fibrin Sealant in Porcine and Rat Dural Injury Models.

STUDY DESIGN: Burst strength study in porcine dural models and functional and histological study in rat dural models. OBJECTIVE: This study aimed to investigate the sealing strength and biocompatibility of Alaska pollock-derived gelatin (ApGltn) and fibrin sealants in disrupted dural injuries. SUMMARY OF BACKGROUND DATA: Disruption of the dura mater occurs during spine surgery, leading to cerebrospinal fluid leakage. Fibrin sealant is usually applied to ruptured sites; however, it lacks sealing strength. A novel biocompatible sealant composed of ApGltn was recently demonstrated to have good burst strength and biocompatibility in the porcine aorta. METHODS: Ten porcine dura maters with central holes were covered with ApGltn and fibrin sealants (five samples per group). The maximum burst strength of each sealant was measured, and histological examination was performed after burst testing. Twenty-seven dura maters of male Wistar rats were used for functional and histopathological evaluations. The rats were treated with three surgical interventions: defect + ApGltn sealant; defect + fibrin sealant; defect alone (nine rats per group). Macroscopic confirmation of the sealant, hindlimb motor function analysis, and histopathological examination were performed at two, four, and eight weeks after the procedure. RESULTS: The maximum burst strength of the ApGltn sealant was ~4.4 times higher than that of the fibrin sealant (68.1±12.1 vs . 15.6±8.7 mmHg; P <0.001). Histological examination confirmed that the ApGltn sealant showed tight adhesion to the dural surface, whereas a gap was observed between the fibrin sealant and the dura mater. In the rat model, the ApGltn sealant resulted in spinal function and dural histological findings similar to those of the fibrin sealant. CONCLUSION: The ApGltn sealant had a higher sealing strength than, and comparable effect on dura regeneration with, the fibrin sealant.

Protective Effects of Extracorporeal Shockwave Therapy on the Degenerated Meniscus in a Rat Model.

BACKGROUND: Loss of meniscal function in association with degenerative changes affects the development and progression of knee osteoarthritis, for which there is currently no effective treatment. Extracorporeal shockwave therapy (ESWT) is an established treatment for musculoskeletal disorders. However, the therapeutic effect of ESWT on meniscal degeneration remains unclear. PURPOSE: To evaluate the therapeutic effect of ESWT on the degenerated meniscus in an anterior cruciate ligament transection (ACLT) model. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve-week-old male Wistar rats were randomly assigned to 3 groups (normal, ESWT-, and ESWT+). Unilateral ACLT of the right knee was performed in the latter 2 groups. At 4 weeks after ACLT, the ESWT+ group received 800 shockwave impulses at an energy flux density of 0.22 mJ/mm2 in a single session. Histological changes were examined in the posterior portion of the medial meniscus after ESWT (n = 15 per group). Real-time polymerase chain reaction (PCR) was performed after ESWT (n = 5 per group) to analyze the expression of connective tissue growth factor/CCN family member 2 (CTGF/CCN2), sex determining region Y-box 9, vascular endothelial growth factor α, aggrecan, collagen type 1 alpha 2, and collagen type 2 alpha 1 (Col2α1). Immunohistochemistry was used to analyze the expression of CTGF/CCN2 and Ki-67 (n = 5 per group) after ESWT. RESULTS: The meniscal histopathological score at 4 weeks after ACLT was significantly higher than that in the normal group, and the score in the ESWT+ group was significantly lower than that in the ESWT- group at 4 and 12 weeks after ESWT. Real-time PCR revealed that the mRNA expression of CTGF/CCN2 and Col2α1 decreased 4 weeks after ACLT. In the ESWT+ group, real-time PCR revealed that the mRNA expression of CTGF/CCN2 increased 24 hours after ESWT, and the expression of Col2α1 increased 4 weeks after ESWT (all significant data were P < .05). The ratio of CTGF/CCN2-positive cells and Ki67-positive cells was significantly higher in the ESWT+ group after ESWT. CONCLUSION: The present study revealed that ESWT might suppress ACLT-induced meniscal degeneration by stimulating cartilage repair factors and inducing collagen type 2. CLINICAL RELEVANCE: ESWT can be an effective treatment to protect the degenerated meniscus in a rat model of ACLT.

Posterior Displacement of Meniscal Ramp Lesion Is Observed on Flexed Knee Magnetic Resonance Imaging of Anterior Cruciate Ligament-Deficient Knees.

PURPOSE: To confirm whether posterior displacement of the detached meniscocapsular structure in ramp lesions could be observed on magnetic resonance imaging (MRI) in the flexed knee position and to clarify whether this displacement on MRI is related to greater anterior knee laxity. METHODS: This retrospective comparative trial study included 50 patients with anterior cruciate ligament injuries in whom attendant ramp lesions were observed on preoperative MRI. All patients underwent 3-T MRI at 120° of knee flexion preoperatively. The gap distance of the ramp lesion on sagittal slices was measured, and a distance greater than 1 mm was classified as gap positive. Additionally, joint effusion in the posteromedial recess was quantitatively evaluated by measuring the surface area of joint fluid. Prior to surgery, the side-to-side difference in anterior tibial translation (ATT) on stress radiographs at 20° of knee flexion was measured to evaluate anterior knee laxity. During anterior cruciate ligament reconstruction, the length of the ramp lesion was measured by a scale from the posteromedial portal. RESULTS: Of the 50 knees, 29 had ramp lesion gaps greater than 1 mm on MRI at knee flexion. The gap-positive group had a significantly greater side-to-side difference in ATT (9.6 ± 3.6 mm vs 5.0 ± 2.7 mm, P < .001) and significantly larger ramp lesion length (15.7 ± 4.9 mm vs 11.7 ± 3.9 mm, P = .002) than the gap-negative group. The gap-positive group also had a significantly greater amount of joint effusion than the gap-negative group (P < .001). CONCLUSIONS: Posterior displacement of the detached meniscocapsular structure in ramp lesions can be observed on MRI at knee flexion and is related to greater anterior knee laxity, lesion size, and joint effusion. LEVEL OF EVIDENCE: Level III, retrospective comparative trial.

Hepatocyte growth factor pretreatment boosts functional recovery after spinal cord injury through human iPSC-derived neural stem/progenitor cell transplantation.

BACKGROUND: Human induced pluripotent stem cell-derived neural stem/progenitor cell (hiPSC-NS/PC)-based cell transplantation has emerged as a groundbreaking method for replacing damaged neural cells and stimulating functional recovery, but its efficacy is strongly influenced by the state of the injured spinal microenvironment. This study evaluates the impact of a dual therapeutic intervention utilizing hepatocyte growth factor (HGF) and hiPSC-NS/PC transplantation on motor function restoration following spinal cord injury (SCI). METHODS: Severe contusive SCI was induced in immunocompromised rats, followed by continuous administration of recombinant human HGF protein into the subarachnoid space immediately after SCI for two weeks. Acute-phase histological and RNA sequencing analyses were conducted. Nine days after the injury, hiPSC-NS/PCs were transplanted into the lesion epicenter of the injured spinal cord, and the functional and histological outcomes were determined. RESULTS: The acute-phase HGF-treated group exhibited vascularization, diverse anti-inflammatory effects, and activation of endogenous neural stem cells after SCI, which collectively contributed to tissue preservation. Following cell transplantation into a favorable environment, the transplanted NS/PCs survived well, facilitating remyelination and neuronal regeneration in host tissues. These comprehensive effects led to substantial enhancements in motor function in the dual-therapy group compared to the single-treatment groups. CONCLUSIONS: We demonstrate that the combined therapeutic approach of HGF preconditioning and hiPSC-NS/PC transplantation enhances locomotor functional recovery post-SCI, highlighting a highly promising therapeutic strategy for acute to subacute SCI.

Postoperative Medial Tilting of the Joint Line and Preoperative Kinematics Influence Postoperative Medial Pivot Pattern Reproduction in Total Knee Arthroplasty.

Background: Reproducing the medial pivot pattern after total knee arthroplasty (TKA) is known to improve patient satisfaction. However, the factors affecting the postoperative medial pivot pattern in TKA are controversial. The purpose of this study was to examine the factors affecting the postoperative medial pivot pattern in posterior-stabilized TKA. Methods: This study involved 30 cases with knee osteoarthritis who underwent primary posterior-stabilized TKA. The preoperative and postoperative kinematics were measured using a computed tomography-free navigation system, and the patients were divided into the following 2 groups: the medial pivot pattern (MP) group and non-medial pivot pattern (non-MP) group. In addition, we measured each of the following angles on X-ray films (preoperative and postoperative femorotibial angle, hip-knee-ankle angle, mechanical lateral distal femoral angle, medial proximal tibial angle). We examine the factors affecting the postoperative medial pivot pattern. Results: There were 14 cases in the MP group and 16 cases in the non-MP group at the preoperative knee kinematic assessment and 17 cases in the MP group and 13 cases in the non-MP group at the postoperative knee kinematic assessment. The preoperative kinematic pattern was conserved after the surgery at a rate of 76.7%. The postoperative MP-group showed a significantly smaller preoperative femorotibial angle and hip-knee-ankle and a significantly smaller postoperative mechanical lateral distal femoral angle and medial proximal tibial angle in comparison to the postoperative non-MP group. Conclusions: Preoperative kinematics and postoperative mechanical lateral distal femoral angle and medial proximal tibial angle may be important factors that affect the postoperative medial pivot pattern.

Insufficient restoration of meniscal extrusion by transtibial pullout repair for medial meniscus posterior root tears.

PURPOSE: The long-term changes in the dynamics of the medial meniscus after transtibial pullout repair for medial meniscus posterior root tears (MMPRTs) are not completely understood. Thus, the aim of this study was to investigate the effects of transtibial pullout repair on MMPRTs and whether the effects would be sustained. METHODS: Nineteen knees with MMPRTs that were treated by trans-tibial pullout repair were enrolled in this study. Medial meniscus extrusion (MME) was measured by ultrasonography during knee extension (no weight-bearing with the knee at 0° extension: NW0°) and 90° flexion (no weight-bearing with the knee at 90° flexion: NW90°) with the patient in the supine position and with full weight-bearing (FW0°) preoperatively and at 3 and 12 months postoperatively. The clinical outcomes were assessed using the Knee Injury and Osteoarthritis Outcome Score, Lysholm score, and International Knee Documentation Committee score. RESULTS: The difference in MME with NW0° was not statistically significant between the preoperative (3.4 ± 1.0 mm) and 12-month postoperative (3.7 ± 0.6 mm) time points. The MME with NW90° at 3 (2.1 ± 0.7 mm) and 12 months (2.9 ± 0.6 mm) postoperatively were significantly lower than the preoperative values (3.4 ± 0.8 mm) (P < 0.05). However, the value significantly increased from 3 to 12 months postoperatively (P < 0.05). The MME with FW0° at 12 months postoperatively (4.3 ± 0.6 mm) was significantly larger than that at pre-operatively (3.6 ± 0.9 mm) (P < 0.05). All the patients' clinical conditions were significantly improved at 12 months postoperatively when compared to their preoperative clinical conditions. CONCLUSION: Surgery did not reduce the extrusion in the no weight-bearing and weight-bearing positions at knee extension, and these values increased in the postoperative period. In addition, while the surgery reduced the extrusion in the knee flexion position, the restoration achieved by the surgery was not sustained in the long term. LEVEL OF EVIDENCE: Level IV.

Microenvironmental modulation in tandem with human stem cell transplantation enhances functional recovery after chronic complete spinal cord injury.

While rapid advancements in regenerative medicine strategies for spinal cord injury (SCI) have been made, most research in this field has focused on the early stages of incomplete injury. However, the majority of patients experience chronic severe injury; therefore, treatments for these situations are fundamentally important. Here, we hypothesized that environmental modulation via a clinically relevant hepatocyte growth factor (HGF)-releasing scaffold and human iPS cell-derived neural stem/progenitor cells (hNS/PCs) transplantation contributes to functional recovery after chronic complete transection SCI. Effective release of HGF from a collagen scaffold induced progressive axonal elongation and increased grafted cell viability by activating microglia/macrophages and meningeal cells, inhibiting inflammation, reducing scar formation, and enhancing vascularization. Furthermore, hNS/PCs transplantation enhanced endogenous neuronal regrowth, the extension of graft axons, and the formation of circuits around the lesion and lumbar enlargement between host and graft neurons, resulting in the restoration of locomotor and urinary function. This study presents an effective therapeutic strategy for severe chronic SCI and provides evidence for the feasibility of regenerative medicine strategies using clinically relevant materials.

Rehabilitative Training Enhances Therapeutic Effect of Human-iPSC-Derived Neural Stem/Progenitor Cells Transplantation in Chronic Spinal Cord Injury.

Cell transplantation therapy using human-induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NS/PCs) is a new therapeutic strategy for spinal cord injury (SCI). Preclinical studies have demonstrated the efficacy of hiPSC-NS/PCs transplantation in the subacute phase of SCI. However, locomotor recovery secondary to hiPSC-NS/PCs transplantation is limited in the chronic phase, suggesting that additional treatment, including rehabilitative training, is required to ensure recovery. The therapeutic potential of hiPSC-NS/PCs that qualify for clinical application is yet to be fully delineated. Therefore, in this study, we investigated the therapeutic effect of the combined therapy of clinical-grade hiPSC-NS/PCs transplantation and rehabilitative training that could produce synergistic effects in a rodent model of chronic SCI. Our findings indicated that rehabilitative training promoted the survival rate and neuronal differentiation of transplanted hiPSC-NS/PCs. The combination therapy was able to enhance the expressions of the BDNF and NT-3 proteins in the spinal cord tissue. Moreover, rehabilitation promoted neuronal activity and increased 5-HT-positive fibers at the lumbar enlargement. Consequently, the combination therapy significantly improved motor functions. The findings of this study suggest that the combined therapy of hiPSC-NS/PCs transplantation and rehabilitative training has the potential to promote functional recovery even when initiated during chronic SCI.

Long-term selective stimulation of transplanted neural stem/progenitor cells for spinal cord injury improves locomotor function.

In cell transplantation therapy for spinal cord injury (SCI), grafted human induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NS/PCs) mainly differentiate into neurons, forming synapses in a process similar to neurodevelopment. In the developing nervous system, the activity of immature neurons has an important role in constructing and maintaining new synapses. Thus, we investigate how enhancing the activity of transplanted hiPSC-NS/PCs affects both the transplanted cells themselves and the host tissue. We find that chemogenetic stimulation of hiPSC-derived neural cells enhances cell activity and neuron-to-neuron interactions in vitro. In a rodent model of SCI, consecutive and selective chemogenetic stimulation of transplanted hiPSC-NS/PCs also enhances the expression of synapse-related genes and proteins in surrounding host tissues and prevents atrophy of the injured spinal cord, thereby improving locomotor function. These findings provide a strategy for enhancing activity within the graft to improve the efficacy of cell transplantation therapy for SCI.

Medial meniscus extrusion as a predictor for a poor prognosis in patients with spontaneous osteonecrosis of the knee.

BACKGROUND: Risk factors for the progression of spontaneous osteonecrosis of the knee (SONK) remain unclear. The purpose of this study was to investigate the association between magnetic resonance imaging (MRI) findings of the meniscus and the prognosis of SONK. METHODS: A total of 78 consecutive patients (female 85%; mean age 75.6 ± 7.2 years old) diagnosed with SONK were included. Of these, 30 patients did not receive surgery within 1 year from the onset of SONK (conservative group), while the remaining 48 patients underwent unicompartmental knee arthroplasty due to worsening of symptoms (UKA group). Using MRI findings obtained within 3 months of the onset, we compared the types of meniscus tear and medial meniscus extrusion between the conservative group and UKA group. We performed a receiver operating characteristics (ROC) analysis to estimate the cut-off value. RESULTS: Patients in the UKA group showed greater medial meniscus extrusion (absolute value, 4.2 mm ± 1.9 vs. 2.8 mm ± 1.2, P = 0.001; relative percentage of extrusion (RPE), 45.7% ± 21.5 vs. 30.7% ± 12.9, P = 0.001) and a higher prevalence of radial tear (P = 0.021) than those in the conservative group. In the multivariate analysis, RPE remained a relevant independent factor (P = 0.035) for future UKA. An ROC analysis found that the cut-off point of RPE was 33% (sensitivity, 81.2%; specificity, 63.3%). CONCLUSION: RPE was a predictor of the prognosis of patients who underwent UKA within 1 year after the onset of SONK. Our results suggest that patients with RPE ≥ 33% are at high risk for progression.

Cell attachment area of rat mesenchymal stem cells correlates with their osteogenic differentiation level on substrates without osteoconductive property.

Cell morphology is related to proliferation and differentiation. We previously reported that cell attachment area of rat mesenchymal stem cells (MSCs) is negatively correlated with their osteogenic differentiation level on osteoconductive hydroxyapatite (HAp) with various microstructures. In this study, the correlation between the cell attachment area and osteogenic differentiation level was investigated on substrates without osteoconductive property using tissue culture polystyrene (TCPS), and 3 mol% yttria-stabilized zirconia (3Y-TZP) with or without surface periodic microstructures. It was found that the osteogenic differentiation level after 3 weeks of culture increased with a decrease in cell attachment area after 3 h of culture. The square of the correlation coefficient between cell attachment area and osteocalcin secretion content was 0.845 among the three types of substrates. Thus, the negative correlation between cell attachment area and differentiation level is confirmed even when cultured on substrates without osteoconductive property. These findings suggest that the correlation between the cell attachment area of rat MSCs and osteogenic differentiation level could also apply to various types of substrate, regardless of osteoconductive property.

Association between upper extremity dysfunction and sleep disturbance in an elderly general population.

OBJECTIVE: Several upper extremity disorders are associated with sleep disturbance in patient populations. This study evaluated the relation between self-assessment of upper extremity function and sleep disturbance in an elderly general population. METHODS: A total of 159 participants (56 men, 103 women, 38-88 years old, mean age of 66.4 years) completed a self-administered questionnaire including items for sex, weight, height, and dominant hand. Upper extremity dysfunction was investigated using Quick Disabilities of the Arm, Shoulder, and Hand of the Japanese Society for Surgery of the Hand. The sleep disturbance severity was evaluated using a Japanese version of the Athens Insomnia Scale. Quality of life was assessed using the EuroQol-5-dimension-3-level, Japanese version. We measured the bilateral hand grip as an indicator of hand muscle function. Statistical tests were applied to clarify the association between upper extremity dysfunction and screening results for sleep disturbance. RESULTS: Of 159 participants, 45 (28.3%) had sleep disturbance as assessed using Japanese version of the Athens Insomnia Scale (11 men and 34 women; mean age of 68.1 years). Japanese version of the Athens Insomnia Scale scores correlated with the EuroQol index; EuroQol visual analog scale; and Quick Disabilities of the Arm, Shoulder, and Hand scores. The Quick Disabilities of the Arm, Shoulder, and Hand score and dominant grip strength of the participants with sleep disturbance were significantly higher than those of the no sleep disturbance group. The EuroQol index score and visual analog scale of those reporting a sleep disturbance were significantly lower than those of the no sleep disturbance group. CONCLUSION: Self-administered upper extremity health condition as assessed using Quick Disabilities of the Arm, Shoulder, and Hand correlated with sleep disturbance. Our results suggest a link between upper extremity conditions and sleep disturbance.

Extracorporeal Shockwave Therapy Accelerates the Healing of a Meniscal Tear in the Avascular Region in a Rat Model.

BACKGROUND: The treatment of meniscal tears in the avascular region remains a clinical challenge. Extracorporeal shockwave therapy (ESWT) is a minimally invasive, safe, and effective therapy for various orthopaedic disorders. However, the therapeutic effect of ESWT on meniscal tears has not been reported. PURPOSE: To evaluate the therapeutic effect of ESWT in the treatment of meniscal tears. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve-week-old male Wistar rats were divided into 3 groups (normal, ESWT-, and ESWT+). The authors made a full-thickness 2-mm longitudinal tear in the avascular region of the anterior horn in the latter 2 groups. At 1 week after surgery, the ESWT+ group received 800 impulses of shockwave at 0.22-mJ/mm2 energy flux density in a single session. The authors performed a histological examination to evaluate meniscal healing (n = 10 for each group) and immunohistochemistry to analyze the expression of bromodeoxyuridine (BrdU; n = 5 for each group) and CCN family member 2/connective tissue growth factor (CCN2/CTGF; n = 5 for each group) at 2, 4, and 8 weeks after ESWT. The mRNA levels of CCN2, SOX 9, VEGF-a, aggrecan, Col1a2, and Col2a1 at the site of the meniscal tear at 4 weeks after ESWT were quantitatively evaluated by a real-time polymerase chain reaction (n = 5 for each group). RESULTS: The meniscus healing scores in the ESWT+ group were significantly higher than those in the ESWT- group at 4 weeks and 8 weeks. The ratio of BrdU-positive cells was the highest in the ESWT+ group at all observation periods. The ratio of CCN2-positive cells was highest in the ESWT+ group at 4 and 8 weeks. In the ESWT+ group, real-time polymerase chain reaction revealed that the levels of CCN2, SOX9, aggrecan, and Col2a1 were upregulated (All significant data were P < .05). CONCLUSION: ESWT promoted the healing of meniscal tears in the avascular area. ESWT stimulated proliferation of meniscal cells and the upregulation of cartilage-repairing factors such as CCN2, with the upregulation of cartilage-specific extracellular matrix expression. CLINICAL RELEVANCE: ESWT may be an effective therapeutic option that promotes meniscal healing in the avascular region.

Younger patients with high varus malalignment of the contralateral knee may be candidates for simultaneous bilateral total knee arthroplasty.

PURPOSE: Bilateral total knee arthroplasty (TKA) is being performed more frequently. However, a consensus on whether simultaneous or staged procedures should be performed is not available. This study reviewed the clinical course of contralateral knees in patients who underwent unilateral TKA (UTKA) to determine which patients are candidates for simultaneous bilateral TKA (BTKA). METHODS: One hundred eighty-six patients with osteoarthritis who underwent UTKA at a single hospital between 2006 and 2009 (follow-up mean, 10.1 years) were retrospectively investigated. Age, sex, obesity, contralateral knee pain, Hospital for Special Surgery score, femorotibial angle (FTA), and Kellgren-Lawrence grades at the time of initial surgery were used to evaluate the risk for requiring contralateral TKA. Survival analysis and receiver-operating characteristic (ROC) analysis were performed. RESULTS: Ninety-one patients (48.9%) underwent contralateral TKA. The FTA of the contralateral knee (CFTA) was an independent related factor (hazard ratio, 1.15; p < 0.001), and the CFTA cut-off value for the next surgery was 183° (area under the curve, 0.85; sensitivity, 80.7%; specificity, 76.2%). The 10-year Kaplan-Meier survival rates for the CFTA < 183° group and the CFTA ≥ 183° group were 79.1% and 27.0%, respectively. In the CFTA ≥ 183° group, age was the predictor of future TKA, and elderly patients tended to not require a second procedure. The age cut-off value for the next surgery was 76 years. CONCLUSIONS: Varus deformities in the contralateral knee predicted additional contralateral TKA. Patients with CFTA ≥ 183° and aged 75 years or younger are considered reasonable candidates for simultaneous BTKA. LEVEL OF EVIDENCE: III.

Factors Associated With Posterior Cruciate Ligament Tightness During Cruciate-Retaining Total Knee Arthroplasty.

BACKGROUND: The purpose of our study was to identify factors affecting posterior cruciate ligament (PCL) tightness during cruciate-retaining total knee arthroplasty. METHODS: A total of 225 varus osteoarthritic knees that underwent cruciate-retaining total knee arthroplasty were included in this study. When the flexion gap was tighter than the extension gap after all bone resection and the lift-off sign was positive during surgery, the PCL was released. The association between PCL release and potential risk factors, such as age, gender, body mass index, preoperative range of motion, anterior cruciate ligament status, preoperative hip-knee-ankle angle (HKA), decrease in posterior condylar offset, and also change in tibial posterior slope angle (TPSA) from preoperative to postoperative measurement, was evaluated by univariate and multivariate logistic regression analyses. RESULTS: The PCL was released in 68 of 225 knees (30.2%). According to the univariate logistic regression analysis, preoperative knee flexion angle (odds ratio [OR], 0.98), anterior cruciate ligament status (OR, 3.94), the decrease in medial (OR, 0.73) and lateral posterior condylar offset (OR, 0.76), preoperative HKA (OR, 1.1), preoperative (OR, 1.15) and postoperative TPSA (OR, 0.77), and the decrease in TPSA (OR, 1.23) were associated with PCL release. Multivariable stepwise logistic regression analysis demonstrated that preoperative HKA (P < .001), postoperative TPSA (P = .02), and the decrease in TPSA (P < .001) were independently associated with PCL release. CONCLUSION: Many factors are associated with PCL tightness. The change in TPSA between preoperative and postoperative measurements was a higher risk factor than postoperative TPSA.

A giant popliteal lipoblastoma in a 23-month-old girl: a case report.

BACKGROUND: Lipoblastomas are rare benign tumors that arise from embryonic white fat and almost always occur in babies and children. Here, we report a case of a giant popliteal lipoblastoma in a 23-month-old Japanese girl that was successfully treated via complete resection. CASE PRESENTATION: Our patient was a 23-month-old Japanese girl. At 6 months of age, she presented at a nearby hospital with a mass on the popliteal side of her lower right leg. She had no symptoms and was diagnosed as having a benign adipose tumor via magnetic resonance imaging. The mass gradually increased in size, and she was referred to our hospital at 1 year and 11 months of age. A physical examination and radiology revealed a localized mass 13 × 10 × 7 cm in size in the aforementioned area that restricted knee movement and caused proximal tibia deformity. Magnetic resonance imaging showed a giant circumscribed subcutaneous mass with multiple partitions that was hyperintense on T1-weighted and T2-weighted images but not fat-saturated on T2-weighted images. Based on these findings, she was diagnosed as having a lipoblastoma. Because the mass surrounded her popliteal artery and vein and part of the popliteal nerve, surgical resection was considered risky, and we opted to simply observe her. However, owing to rapid growth of the mass and the worsening of symptoms, she underwent complete resection at 2 years and 6 months of age. A histological examination confirmed the diagnosis of a lipoblastoma. She was discharged from our hospital 3 days after surgery with no symptoms. She could walk without pain at the 6-month follow-up, and no local recurrence was observed. CONCLUSIONS: We successfully treated a giant popliteal lipoblastoma without complications by performing a total resection. Our report provides evidence that lipoblastomas should be considered for surgical resection when they progress or symptoms appear.

Bone turnover markers and the factors associated with atypical femur fractures among Japanese patients.

Many previous reports have indicated that atypical femur fractures (AFFs) are associated with the administration of bisphosphonates (BPs). A number of risk factors and hypotheses regarding the pathogenesis of AFFs have been reported to date. The purpose of the present study was to identify the factors associated with AFFs in Japanese individuals and to elucidate the association between bone metabolism and AFFs by evaluating bone turnover markers (BTMs). We prospectively reviewed all patients with femur fractures and identified the patients with AFFs and typical femur fractures (TFFs). We collected the demographic and clinical data that were relevant to the present study, namely age, gender, affected side, affected site, concomitant medical history, and comorbid conditions, and measured the levels of BTMs within 24h after trauma. Welch's test and Fisher's exact probability test were used for the statistical analyses. A total of 338 patients, including 10 patients with AFFs and 328 patients with TFFs, were analyzed under the inclusion criteria. The use of BPs (p<0.001) and collagen disease and chronic granulomatous disease (CD/CGD) (p=0.025) were more frequently observed in patients with AFFs than in patients with TFFs, while the levels of BTMs, including N-terminal propeptides of type 1 procollagen (P1NP), isoform 5b of tartrate-resistant acid phosphatase (TRACP-5b) and undercarboxylated osteocalcin (ucOC) were significantly lower in patients with AFFs than in patients with TFFs. Furthermore, the level of TRACP-5b was found to be significantly lower in patients with atypical subtrochanteric fractures than in atypical diaphyseal fractures (p=0.025). Moreover, the levels of P1NP (p=0.016) and TRACP-5b (p=0.015) were found to be significantly lower in patients with AFFs than in patients with TFFs in a subgroup analysis of BPs users. The use of BPs was considered to be a factor associated with AFFs. Our comparison of the BTMs in patients with AFFs and TFFs indicated that the severe suppression of bone turnover was associated with the pathogenesis of AFFs. The extent of the influence of suppressed turnover on the pathogenesis of AFFs may differ depending on the fracture site.