Rotational and Varus Instability in Chronic Lateral Ankle Instability: In Vivo 3D Biomechanical Analysis.

We retrospectively evaluated the altered biomechanics of the talus in 15 adult patients (7 males, 8 females) with chronic lateral ankle instability when the ankle joint moved actively from full dorsiflexion to full plantarflexion under a non-weight bearing condition. CT images were taken for the unstable ankle and the contralateral normal (control) ankle. Three-dimensional surface models of both ankle joints were reconstructed from the CT data, and we used a computer simulation program to compare both ankle motions of inversion/eversion in the coronal plane, plantarflexion/dorsiflexion in the sagittal plane, and internal rotation/external rotation in the axial plane. This evaluation method provides in vivo, dynamic, and 3D results of ankle motion. In the ankles with chronic lateral instability and the controls, the average talar rotational movement of inversion (+)/eversion (-) was 19.0° and 15.5° and the internal rotation (+)/external rotation (-) was 30.4° and 20.7°, respectively. Paired t-tests revealed significant differences in the amount of inversion (+)/eversion (-) (p=0.012) and internal rotation (+)/external rotation (-) (p<0.001) between unstable and normal ankle joints. The difference of mean rotational movement in internal rotation (9.7°) was greater than that of inversion (3.5°). Rotational instability should be considered when evaluating chronic lateral ankle instability.

Why do subchondral cysts occur at the medial aspect of the femoral head in hip dysplasia?

INTRODUCTION: Osteoarthritis in dysplastic hips should develop from the lateral side of the acetabulum and the femoral head just below. However, the existence of subchondral cysts located more on the medial side contradicts the weight-loading theory. The aim of this study was to confirm the presence of medial cysts at the femoral head and to investigate the relationship between medial cysts and injuries of the ligamentum teres in hip dysplasia. METHODS: A retrospective analysis was conducted on 257 cases of hip dysplasia. All patients had x-rays and 3-dimensional computed tomographies (3D CT) preoperatively and 123 patients had magnetic resonance arthrographies. A comparison was performed between cases with and without medial cysts according to the severity of damage to the ligamentum teres, the presence of bony spurs around the fovea capitis, and the Tönnis grade. RESULTS: Medial subchondral cysts around the fovea capitis were found in 100 cases. Mild osteoarthritis (Tönnis grade 0 or 1) was present in 89% of cases in the medial cyst group. A significant difference between the groups was observed in the incidence of bony spurs around the fovea capitis (p < 0.05) and injuries of the ligamentum teres (p < 0.05). CONCLUSIONS: The formation of subchondral cysts at the medial femoral head in hip dysplasia may be related to damage in the ligamentum teres. Considering that subchondral cysts develop in early osteoarthritis, the progression of arthritis in hip dysplasia appears to correlate with damage to the ligamentum teres, as well as compressive pressure on the joint.

A study on the relationship between the rate of vertebral body height loss before balloon kyphoplasty and early adjacent vertebral fracture.

BACKGROUND: The number of patients with an osteoporotic vertebral compression fracture, which is often accompanied by lower back pain and restrained activities, is growing. Balloon kyphoplasty involves the inflation of a balloon to restore height and reduce kyphotic deformity before stabilization with polymethylmethacrylate. However, there is a great deal of debate about whether balloon kyphoplasty also increases fracture morbidity by either inducing or facilitating subsequent adjacent vertebral fractures. OBJECTIVE: To evaluate the relationship between the rate of vertebral body height loss before balloon kyphoplasty and the etiology of early adjacent vertebral fracture after augmentation. METHODS: A total of 59 patients with osteoporotic vertebral compression fractures who underwent kyphoplasty were enrolled. This study defined early adjacent segmental fractures as new fractures occurring within three months after surgery. This study included the rate of vertebral body height loss. RESULTS: Early adjacent vertebral fractures were diagnosed in nine (15%) of the 59 patients. The patients were divided into two groups, with and without adjacent vertebral fractures. There was no significant difference in terms of age, body mass index, bone mineral density, local kyphotic angle, Cobb's angle, cement volume, cement leakage, and percent height restored between the groups with fractures and without fractures. There was a statistically significant difference between the two groups in the rate of vertebral body height loss. The rate of vertebral body height loss was significantly higher in the fracture group than in the without fracture group. CONCLUSIONS: A high rate of vertebral body height loss increased the risk of early adjacent vertebral fractures after balloon kyphoplasty.

Comparison of hip subregion bone mineral density to the type of proximal femur fracture.

Beta values of the intertrochanteric fracture group were about twice as high as those of the femoral neck fracture group. These results can be used to increase the awareness of proximal hip fracture among physicians and improve treatments and outcomes. PURPOSE: To compare the BMD of the femoral neck region and the intertrochanteric region between the femoral neck fracture group and the intertrochanteric fracture group. METHODS: We did a retrospective review of radiographs of the proximal femoral fractures in patients registered from 2010 to 2017. A total of 329 patients were classified into the femoral neck fracture group (group A, n = 162) and the femur intertrochanteric fracture group (group B, n = 167). We did intergroup comparisons of age, sex, BMI (body mass index), and bone mineral density (BMD) of the neck and intertrochanteric region, adjusting for age. We did multiple logistic regression analysis among these parameters. RESULTS: The BMD of the femoral neck and intertrochanteric was statistically significantly different between the two groups (p < 0.001), and the BMD of the femur intertrochanteric was also significantly different between the two groups (p < 0.001). BMD of both regions in the intertrochanteric fracture group was lower than that of the femoral neck fracture group. In linear regression analysis, the beta values of the intertrochanteric fracture group were about twice as high as those of the femoral neck fracture group. CONCLUSION: In linear regression analysis, the beta values of the intertrochanteric fracture group were about twice as high as those of the femoral neck fracture group.

Correction to: Comparison of hip subregion bone mineral density to the type of proximal femur fracture.

The original version of this article, published on 05 August 2020, unfortunately contained a mistake.

Postoperative radiologic outcome comparison between conventional and computer-assisted navigation total knee arthroplasty in extra-articular tibia vara.

PURPOSE: Total knee arthroplasty (TKA) is the definite treatment for osteoarthritis. Meanwhile, significant inherent extra-articular varus angulation is associated with abnormal postoperative hip-knee-ankle (HKA) angle. Computer-assisted navigation TKA (CAS-TKA) used in patients who have severe varus deformity. The purpose of this study was to compare postoperative radiologic outcome between CAS-TKA and conventional TKA for extra-articular tibia vara. METHODS: A retrospective review of postoperative HKA on standing lower extremity views was conducted in patients who underwent TKA by a single surgeon from 2010 to 2018, including knee with conventional TKA (n = 83) and CAS-TKA (n = 246). Extra-articular tibia vara was assessed by measuring the metaphyseal-diaphyseal angle (MDA) of the tibia in preoperative standing lower extremity view. Postoperative alignment was assessed by measuring the HKA in postoperative standing lower extremity view. RESULTS: There was no significant difference in age (p = 0.063), gender (p = 0.628), body mass index (p = 0.426), preoperative range of motion (p = 0.524), preoperative HKA (p = 0.306), preoperative MDA (p = 0.523), or postoperative HKA (p = 0.416) between the two groups (conventional TKA and CAS-TKA). There was no significant difference in postoperative alignment for cases with MDA ≤4° (p = 0.351) or MDA >4° (p = 0.866) in each group. There was a positive correlation between preoperative HKA and postoperative HKA in the CAS-TKA group (p < 0.001, r = 0.243). However, there was no significant correlation between preoperative HKA and postoperative HKA in the conventional TKA group (p = 0.732). CONCLUSIONS: There was no significant difference in postoperative alignment between conventional TKA and CAS-TKA in extra-articular tibial vara even for cases with MDA >4°.

Should We Check the Routine Postoperative MRI for Hematoma in Spinal Decompression Surgery?

BACKGROUND: A postoperative magnetic resonance imaging (MRI) is performed as a routine to assess decompression of the spinal cord as well as to evaluate postoperative complications. The purpose of this study is to analyze the efficacy of postoperative MRI for hematoma in spinal decompression surgery. METHODS: Between January 1, 2008 and January 31, 2015, 185 patients who underwent postoperative MRI after spinal decompression surgery were included in this study. We checked the history of the use of an anticoagulant or antiplatelet agent, withdrawal period, blood platelet count, and prothrombin time (international normalized ratio [INR]). We measured the total amount of suction drainage and duration until removal. We retrospectively reviewed the presence of hematoma and thecal sac compression. Postoperative prognosis was evaluated by a visual analog scale (VAS) and the Oswestry Disability Index (ODI). RESULTS: Hematomas were found on postoperative MRI scans in 97 out of 185 patients (52.4%). Thirty patients had a thecal sac compressing hematoma: 7 in the cervical spine, 1 in the thoracic spine, and 22 in the lumbar spine. The occurrence of hematoma did not show significant difference according to the use of an anticoagulant (p = 0.157). The blood platelet count, prothrombin time (INR), and suction drainage duration did not have a statistically significant correlation with the occurrence of hematoma (p = 0.562, p = 0.506, and p = 0.429, respectively). The total amount of suction drainage was significantly different according to the presence of hematoma (p = 0.022). The total 185 patients had a significant decrease in the postoperative VAS score (p < 0.001), and the diminution of VAS score was not significantly different according to the occurrence of hematoma (p = 0.243). Even in the cases of thecal sac compressing hematoma, the reduction of VAS score was not significantly different (p = 0.689). CONCLUSIONS: Postoperative MRI for hematoma in spinal decompression surgery has little effect on prognosis or management. Therefore, indiscriminate postoperative MRI should be avoided and MRI should be performed depending on the patient's status.

Risk factors and clinical outcomes of delirium in osteoporotic hip fractures.

PURPOSE: This study is performed to identify risk factors for delirium in osteoporotic hip fractures and to evaluate the hospitalization cost and clinical outcomes of delirium in osteoporotic hip. METHODS: A total of 221 patients with osteoporotic hip fractures were assessed for eligibility between 2010 and 2014. Among them, 37 patients with delirium were allocated into the delirium group (group D) and 37 patients without delirium were allocated into the non-delirium group (group ND) by matching demographic factors. Risk factors such as time between admission and operation, body mass index, American Society of Anesthesiologists status, cognitive impairment, preoperative urinary catheter, electrolyte imbalance, preoperative hemoglobin, polymedication (medications > 5), pneumonia, anesthesia time, operation time, estimated blood loss, and total amount of transfusion were evaluated for correlation with incidence of delirium. The hospitalization cost was evaluated, and clinical outcomes such as readmission, mortality, and activity level at 1-year follow-up were evaluated. RESULTS: In multivariate analysis, polymedication ( p = 0.028) and preoperative indwelling urinary catheter insertion status ( p = 0.007) were related to the incidence of delirium in patients with osteoporotic hip fractures. Group D showed a significantly higher hospitalization cost compared to group ND. However, delirium did not have a significant effect on length of hospital stay, readmission rate, postoperative 1-year mortality, and activity level. CONCLUSIONS: Polymedication and preoperative urinary catheter were related to perioperative delirium. In addition, delirium in osteoporotic hip fractures may not have a detrimental effect on clinical outcomes; however, hospitalization cost seemed to be increased due to delirium.

Comparison of patellar tracking according to different angles of external rotation of femoral component in varus knee of Asians.

PURPOSE: Racial difference in the femoral geometry may exist. Asian femurs may be more externally rotated. If anatomical differences in distal femur had existed between Caucasians and Asians, the group with 5° external rotation of the femoral component should have shown better results than the group with 3° external rotation of the femoral component have. METHODS: 598 patients underwent total knee arthroplasty in our institution, among whom 83 patients (115 knees) who had postoperative computed tomography (CT) were studied retrospectively. Sixty-two knees were set in 5° of external rotation of femoral component relative to the posterior condylar axis (group A) while the others (53 knees) were set in 3° (group B). The femoral component rotation (FCR) was measured and compared using CT. The patellar tilting (PT) and the lateral patellar displacement (LPD) were measured to evaluate the patellar tracking using Merchant view. And postoperative clinical scores were compared. RESULTS: The mean FCRs showed no significant difference between two groups ( p > 0.05). The mean PT and LPD showed no statistically significant difference either ( p > 0.05). There were no statistical differences in clinical scores. CONCLUSION: The difference in the patellar tracking between the two groups could not be demonstrated. There were no statistical differences in clinical scores either. We concluded there is no need to adhere to 5° external rotation.

Construction of the bifunctional enzyme cellulase-beta-glucosidase from the hyperthermophilic bacterium Thermotoga maritima.

An artificial bifunctional enzyme, cellulase-beta-glucosidase, was prepared by gene fusion from the hyperthermophilic bacterium Thermotoga maritima MSB8. The fusion protein exhibited both cellulase (Cel5C) and beta-glucosidase (BglB) activity when the bglB gene was fused to downstream of cel5C, but not when cel5C was fused to downstream of bglB. The specific activity of the bifunctional enzyme was 70% lower than that of cellulase or beta-glucosidase. The fusion enzyme was purified, and the MW was estimated as 114 kDa. The fusion enzyme displayed optimum cellulase activity at pH 8.0 and 70 degrees C over 30 min, and optimal beta-glucosidase activity at pH 7.0 and 80 degrees C over 30 min.