Cut-off values of preoperative knee extensor strength and hip abductor strength for predicting good walking ability after total knee arthroplasty.

INTRODUCTION: Total knee arthroplasty (TKA) reduces pain and improves physical function; however, not all patients have successful outcomes after surgery. To identify these patients would be critical information for improving rehabilitation programs. The purpose of this study was to clarify the cut-off values of lower extremity muscle strength for predicting postoperative good walking ability. MATERIALS AND METHODS: Timed Up and Go test of 105 patients was measured at 6 months postoperatively, and participants were divided into good (< 9.1 s) and poor (≥ 9.1 s) walking ability. Both sides of knee extensor strength (KES) and hip abductor strength (HAS) were measured using hand-held dynamometer preoperatively. Receiver operating characteristic (ROC) curve analysis was used to identify cut-off values for classifying the participants into the two groups. RESULTS: Of the 105 patients, 54 were allocated in the poor walking ability group, whereas 51 were allocated in the good walking ability group. KES and HAS were significantly greater in the good walking ability group than in the poor walking ability group. ROC curve analysis revealed that the cut-off value for KES was 0.79 Nm/kg (area under the curve (AUC) 0.68; sensitivity 64.7%; specificity 68.5%) on the involved side and 0.86 Nm/kg (AUC 0.73; sensitivity 84.6%; specificity 55.6%) on the uninvolved side, and for HAS was 0.57 Nm/kg (AUC 0.71; sensitivity 60.8%; specificity 71.7%) on the involved side and 0.61 Nm/kg (AUC 0.76; sensitivity 66.7%; specificity 77.4%) on the uninvolved side. CONCLUSION: The cut-off values of preoperative KES and HAS for predicting good walking ability after TKA are 0.79 Nm/kg on the involved side and 0.86 Nm/kg on the uninvolved side, and 0.57 Nm/kg on the involved side and 0.61 Nm/kg on the uninvolved side, respectively. We should provide enhanced pre- and post-operative rehabilitation programs for patients with muscle strength lower than these values.

Which head element is more effective for cement augmentation of TFNA? Helical blade versus lag screw.

BACKGROUND: Early fixation and rehabilitation is the gold standard treatment for intertrochanteric femur fractures. Cement augmentation through perforated head elements has been developed to avoid postoperative complications such as cut-out or cut-through. The purpose of this study was to compare two head elements in terms of cement distribution using computed tomography (CT) and to examine their initial fixation and clinical outcomes. METHODS: Elderly patients who had intertrochanteric fractures were treated with a trochanteric fixation nail advanced (TFNA) helical blade (Blade group) or a TFNA lag screw (Screw group). In both groups, 4.2 mL of cement was injected under an image intensifier (1.8 mL of cement was directed cranially and 0.8 mL each caudally, anteriorly, and posteriorly). Patient demographics and clinical outcome were investigated post-operatively. Cement distribution from the center of the head element was evaluated with CT. Maximum penetration depth (MPD) were measured in the coronal and sagittal planes. On each axial plane, the cross-sectional areas in the cranial, caudal, anterior and posterior directions were calculated. The sum of cross-sectional areas (successive 36 slices) was defined as the volume of the head element. RESULTS: The Blade group included 14 patients, and the Screw group included 15 patients. In the Blade group, MPD in the anterior and caudal direction was significantly greater than that in the posterior direction (p < 0.01). In the Screw group, volume in the cranial and posterior direction was significantly greater than that in the Blade group (p = 0.03). Subsequently, the total volume in the Screw group was significantly larger than that in the Blade group (p < 0.01). No significant correlation was detected between bone mineral density, T score, young adult mean, and total cement volume. Change in radiographic parameters and clinical outcome such as Parker score and visual analog scale were similar in both groups. No patients suffered from cut-out / cut through or non-union. CONCLUSIONS: The position of cement distribution through the lag screw is different from that through the helical blade, and the total volume of the head element is significantly larger in the lag screw. Both groups had similarly effective results in terms of mechanical stability after surgery, postoperative pain and early phase of rehabilitation. TRIAL REGISTRATION: Current Controlled Trials ISRCTN45341843, 24/12/2022, Retrospectively registered.

Correction loss following short-segment posterior fixation for traumatic thoracolumbar burst fractures related to endplate and intervertebral disc destruction.

BACKGROUND: There has been widespread use of short-segment posterior fixation (SSPF) for traumatic thoracolumbar burst fractures. The relationship between the destruction of the vertebral endplate and adjacent disc and postoperative correction loss has been studied in only a few studies. This study investigated the risk factors for correction loss following SSPF. METHODS: Forty-eight patients (mean age 35.0 years) who underwent SSPF for thoracolumbar burst fractures were enrolled. The mean follow-up period was 25.7 months (12-98 months). The neurological status and postoperative back pain were assessed by the medical records. Segmental kyphotic angle (SKA) and anterior vertebral body height ratio (AVBHR) were measured radiographically to assess indirect vertebral body reduction and local kyphosis. Preoperative Sander's traumatic intervertebral disc lesion (TIDL) classification and AO classification were used to evaluate the severity of disc and vertebral endplate injury. The corrective loss was considered present if ΔSKA was ≥10°. A multivariate logistic regression analysis was performed to identify the risk factors associated with postoperative loss of correction. RESULTS: The fracture distribution was as follows: 10 at T12, 17 at L1, 10 at L2, 9 at L3, and 2 at L4. Vertebral fractures were classified in the following way: A3 in 13 patients, A4 in 11, B1 in 11, and B2 in 13. In 47 patients (98%), a union of the fractured vertebrae was achieved. SKA and AVBHR improved significantly after surgery from 11.6° to 3.5° and from 67.2 to 90.0%, respectively. However, the correction loss at follow-up was 10.4° and 9.7%, respectively. Twenty patients (42%) had severe TIDL (grade 3). Postoperative ΔSKA and ΔAVBHR were significantly higher in patients with TIDL grade 3 than with TIDL grade 0-2. The presence of cranial TIDL grade 3 and older age were significant risk factors for ΔSKA ≥10° on multivariate logistic regression analysis. All patients could walk at follow-up. TIDL grade 3 and ΔSKA ≥10° were associated with severe postoperative back pain. CONCLUSIONS: Risk factors for loss of correction after SSPF for thoracolumbar burst fractures were severe disc and endplate destruction at the time of injury and older age.

Association of preoperative muscle composition of the lower extremity with gait function after total knee arthroplasty.

BACKGROUND: Limitations of gait function persist in some patients with knee osteoarthritis after total knee arthroplasty. This study aimed to identify preoperative muscle composition variables of the operated limb associated with postoperative gait function. METHODS: Longitudinal data from 45 patients who underwent unilateral primary total knee arthroplasty were retrospectively analyzed. Timed Up-and-Go test and gait speed were measured preoperatively and at 3 and 6 months postoperatively. Preoperative muscle composition in the glutei medius and minimus, the quadriceps, the hamstrings, and combination of the hamstrings and quadriceps were evaluated by computed tomography. The area ratio of the individual muscle composition to the total muscle was calculated. The factors associated with Timed Up-and-Go test and gait speed were identified using stepwise regression analysis. RESULTS: Shorter Timed Up-and-Go test and faster gait speed at each time point correlated with higher lean muscle mass area of the total hamstrings, higher area ratio of lean muscle mass to the total hamstrings or to combination of the hamstrings and quadriceps, and lower area ratio of low density lean tissue or intramuscular adipose tissue to the total hamstrings. Shorter Timed Up-and-Go test at each time point also correlated with higher combined area of lean muscle mass of the hamstrings and quadriceps. Faster gait speed at each time point additionally correlated with lower area ratio of intramuscular fat to the total hamstrings and lower area ratio of lean tissue mass or intramuscular adipose tissue to combination of the hamstrings and quadriceps. Regression analysis using the significant muscle composition variables revealed that the area ratio of lean muscle mass to the total hamstrings was the only predictor of Timed Up-and-Go test and gait speed after operation. CONCLUSIONS: Preoperative area ratio of ipsilateral lean muscle mass to the total hamstrings could predict gait function after total knee arthroplasty.

Wrong-level spine surgery: A multicenter retrospective study.

BACKGROUND: Wrong-level spine surgery is a rare but serious complication of spinal surgery that increases patient harm and legal risks. Although such surgeries have been reported by many spine surgeons, they have not been adequately investigated. Therefore, this study aimed to examine the causes and preventive measures for wrong-level spine surgeries. METHODS: This study analyzed cases of wrong-level spine surgeries from 10 medical centers. Factors such as age, sex, body mass index, preoperative diagnosis, surgical details, surgeon's experience, anatomical variations, responses, and causes of the wrong-level spine surgeries were studied. The methods used by the surgeons to confirm the surgical level were also surveyed using a questionnaire for each surgical procedure and site. RESULTS: Eighteen cases (13 men and 5 women; mean age, 61.2 years; mean body mass index, 24.5 kg/m2) of wrong-level spine surgeries were evaluated in the study. Two cases involved emergency surgeries, three involved newly introduced procedures, and five showed anatomical variations. Wrong-level spine surgeries occurred more frequently in patients who underwent posterior thoracic surgery than in those who underwent other techniques (p < 0.01). Twenty-two spinal surgeons described the methods used to confirm the levels preoperatively and intraoperatively. In posterior thoracic laminectomies, half of the surgeons used preoperative markers to confirm the surgical level and did not perform intraoperative fluoroscopy. In posterior thoracic fusion, all surgeons confirmed the level using fluoroscopy preoperatively and intraoperatively. CONCLUSIONS: Wrong-level spine surgeries occurred more frequently in posterior thoracic surgeries. The thoracic spine lacks the anatomical characteristics observed in the cervical and lumbar spine. The large drop in the spinous process can make it challenging for surgeons to determine the positional relationship between the spinous process and the vertebral body. Moreover, unfamiliarity with the technique and anatomical variations were also risk factors for wrong-level spine surgeries.

Minimally invasive transiliac anatomical locking plate for posterior pelvic ring injury: a retrospective analysis of clinical outcomes and radiographic parameters for the gull wing plate.

BACKGROUND: Posterior pelvic ring injuries are challenging for surgeons to treat adequately due to difficulties with reduction and stabilization. Surgical intervention is a beneficial option to protect neurological structures and provide sufficient stability for early mobilization. The gull wing plate (GWP) is a pre-contoured anatomical locking plate with six screws, and its design is unique among posterior transiliac tension-band plates. The purpose of this study was to investigate clinical results of the GWP. METHODS: Patients who had an unstable posterior pelvic ring injury and underwent internal fixation with GWP were retrospectively analyzed at a trauma center. Demographic data, fracture type, perioperative data, and radiological evaluation with computed tomography (CT) were collected. Clinical outcomes were graded using the functional independence measure (FIM) and Majeed outcome score. RESULTS: Twenty-six patients were enrolled (mean age, 54 years), and the mean follow-up period was 23 months. The mean Injury Severity Score was 24 points, and internal fixation was performed 6.6 days post-trauma. CT evaluation showed the lateral surface angle of the uninjured ilium was approximately 68°. The GWP pre-contoured anatomical design closely matched this angle. The mean FIM and Majeed score were 119 and 76 points, respectively, which were graded as excellent (n = 14), good (n = 9), or fair (n = 3). CONCLUSIONS: With the retrospective single-center data available, the GWP seems to be a minimally-invasive alternative, provides reliable stability of the posterior pelvic ring and allows for rehabilitation within normal ranges.

Mortality related to and functional outcomes of upper cervical spine fractures in the elderly.

BACKGROUND: Although the mortality related to hip fracture and osteoporotic vertebral fracture have been reported, few studies have examined the mortality related to atlas and/or axis fractures. The aim of this study was to assess the association between mortality and atlas and/or axis fractures retrospectively and to elucidate the efficacy of surgical treatment. METHODS: A total of 33 elderly patients who were treated for atlas and/or axis fractures at our institution between January 2012 and December 2018 were included in this study. These patients were divided into two groups: surgical treatment and conservative treatment. Fracture types, comorbidities, neurological status, treatment types, and walking ability at follow-up were reviewed. Mortality was assessed using medical records or via phone interviews. RESULTS: The mean age at injury was 79.9 ± 8.0 years, and the mean follow-up period was 2.3 years. The overall mortality rates at 1 and 5 years were 21.4% and 48.4%, respectively. During the observation period, 12 (36%) patients died. Twenty-two patients were treated conservatively (14 were treated with a cervical collar, 8 were treated with a halo vest). Surgical procedures included occipital-cervical fixation, osteosynthesis of C2 fractures, C1-2 fixation, and C1-4 fixation using a posterior approach. Surgical treatment correlated with better survival rates. There was no significant difference between the two groups in terms of ambulatory ability and functional recovery. CONCLUSION: Upper cervical spine fractures appear to have a worse prognosis compared to hip and osteoporotic vertebral fractures. This study indicates the efficacy of surgical treatment for upper cervical spine fractures in the elderly for improving survival prognosis.

Endothelial cell-related autophagic pathways in Sugen/hypoxia-exposed pulmonary arterial hypertensive rats.

Pulmonary arterial hypertension (PAH) is characterized by progressive obstructive remodeling of pulmonary arteries. However, no reports have described the causative role of the autophagic pathway in pulmonary vascular endothelial cell (EC) alterations associated with PAH. This study investigated the time-dependent role of the autophagic pathway in pulmonary vascular ECs and pulmonary vascular EC kinesis in a severe PAH rat model (Sugen/hypoxia rat) and evaluated whether timely induction of the autophagic pathway by rapamycin improves PAH. Hemodynamic and histological examinations as well as flow cytometry of pulmonary vascular EC-related autophagic pathways and pulmonary vascular EC kinetics in lung cell suspensions were performed. The time-dependent and therapeutic effects of rapamycin on the autophagic pathway were also assessed. Sugen/hypoxia rats treated with the vascular endothelial growth factor receptor blocker SU5416 showed increased right ventricular systolic pressure (RVSP) and numbers of obstructive vessels due to increased pulmonary vascular remodeling. The expression of the autophagic marker LC3 in ECs also changed in a time-dependent manner, in parallel with proliferation and apoptotic markers as assessed by flow cytometry. These results suggest the presence of cross talk between pulmonary vascular remodeling and the autophagic pathway, especially in small vascular lesions. Moreover, treatment of Sugen/hypoxia rats with rapamycin after SU5416 injection activated the autophagic pathway and improved the balance between cell proliferation and apoptosis in pulmonary vascular ECs to reduce RVSP and pulmonary vascular remodeling. These results suggested that the autophagic pathway can suppress PAH progression and that rapamycin-dependent activation of the autophagic pathway could ameliorate PAH.

Risk factors for preoperative neurological impairment in patients with spinal meningioma: A retrospective multicenter study.

BACKGROUND: Patients with spinal meningioma may present preoperatively with paralysis and sensory deficits. However, there is a paucity of detailed evaluations and a lack of consensus regarding imaging findings that are predictive of neurological symptoms in patients with spinal meningioma. METHODS: Herein, a total of 55 patients who underwent surgical resection of spinal meningiomas in eight hospitals between 2011 and 2021 were enrolled. Patient characteristics, degree of muscle weakness, sensory disturbances, and the presence of bowel/bladder dysfunction (BBD) before surgical treatment were evaluated using medical records. Patients with American Spinal Injury Impairment Scale grades A-C and the presence of BBD were classified into the paralysis (+) group. Patients with sensory disturbances were assigned to the sensory disturbance (+) group. Based on magnetic resonance (MR) and computed tomography images, the tumor location was classified according to the spinal level and its attachment to the dura mater. To evaluate tumor size, the tumor occupation ratio (OR) was calculated using the area and distance measurement method in horizontal MR images, and the maximum length and area of the tumor in the sagittal plane were measured. RESULTS: Of all patients, 85 % were women. The mean age of patients at surgery was 69.7 years. Twenty-eight (51 %) and 41 (75 %) patients were classified into the paralysis (+) and sensory disturbance (+) groups, respectively. The average tumor length and area in the sagittal plane were 19.6 mm and 203 mm2, respectively; OR-area and diameters were 70.3 % and 72.3 %, respectively. In univariate analyses, tumor length and area in the sagittal plane were significant risk factors for paralysis. OR-diameter, symptom duration, and a low MIB-1 index correlated with sensory disturbances. Multivariate logistic regression analysis demonstrated that the area and length of the tumor in the sagittal plane were significantly correlated with paralysis, whereas the OR-diameter and symptom duration significantly correlated with sensory disturbances. The cut-off values for the area and length of the tumor in the sagittal plane to predict paralysis were 243 mm2 and 20.1 mm, respectively. CONCLUSIONS: Preoperative paralysis in patients with spinal meningiomas was significantly associated with sagittal tumor size than with high tumor occupancy in the horizontal plane. Sensory disturbances were associated with high occupancy in the horizontal plane. Patients with spinal meningiomas > 20 mm in length or 243 mm2 in area in the sagittal plane are at risk of developing paralysis and could be considered for surgery even in the absence of paralysis.

Hox11 genes establish synovial joint organization and phylogenetic characteristics in developing mouse zeugopod skeletal elements.

Hox11 genes are essential for zeugopod skeletal element development but their roles in synovial joint formation remain largely unknown. Here, we show that the elbow and knee joints of mouse embryos lacking all Hox11 paralogous genes are specifically remodeled and reorganized. The proximal ends of developing mutant ulna and radius elements became morphologically similar and formed an anatomically distinct elbow joint. The mutant ulna lacked the olecranon that normally attaches to the triceps brachii muscle tendon and connects the humerus to the ulna. In its place, an ulnar patella-like element developed that expressed lubricin on its ventral side facing the joint and was connected to the triceps muscle tendon. In mutant knees, both tibia and fibula fully articulated with an enlarged femoral epiphyseal end that accommodated both elements, and the neo-tripartite knee joint was enclosed in a single synovial cavity and displayed an additional anterior ligament. The mutant joints also exhibited a different organization of the superficial zone of articular cartilage that normally exerts an anti-friction function. In conclusion, Hox11 genes co-regulate and coordinate the development of zeugopod skeletal elements and adjacent elbow and knee joints, and dictate joint identity, morphogenesis and anatomical and functional organization. Notably, the ulnar patella and tripartite knee joints in the mouse mutants actually characterize several lower vertebrates, including certain reptiles and amphibians. The re-emergence of such anatomical structures suggests that their genetic blueprint is still present in the mouse genome but is normally modified to the needs of the mammalian joint-formation program by distinct Hox11 function.

Lectin-like oxidized low-density lipoprotein receptor 1 signal is a potent biomarker and therapeutic target for human rheumatoid arthritis.

OBJECTIVE: To determine whether lectin-like oxidized low-density lipoprotein (ox-LDL) receptor 1 (LOX-1) and the soluble form of LOX-1 (sLOX-1) are novel target molecules for the diagnosis and treatment of rheumatoid arthritis (RA). METHODS: Expression of ox-LDL and LOX-1 proteins in human RA synovium was evaluated by immunohistochemistry. Human RA fibroblast-like synoviocytes (FLS) were assessed for ox-LDL-induced expression of LOX-1 and ox-LDL-induced production of matrix metalloproteinase 1 (MMP-1) and MMP-3. Levels of sLOX-1 in the plasma and synovial fluid of patients with RA, compared with patients with osteoarthritis (OA), were determined by a specific chemiluminescence enzyme-linked immunoassay. In animal experiments, ox-LDL was injected into the knee joints of mice, with or without an anti-LOX-1 neutralizing antibody or sLOX-1, and the severity of arthritis was analyzed by histology and immunohistochemistry. RESULTS: Oxidized LDL and LOX-1 proteins were detected in the RA synovial tissue. Levels of MMP-1 and MMP-3 were enhanced by stimulation of RA FLS with ox-LDL, and the production of both MMPs was inhibited by blockade of the ox-LDL-LOX-1 interaction with the anti-LOX-1 neutralizing antibody or sLOX-1. Levels of sLOX-1 in the plasma and synovial fluid of RA patients were significantly higher than those in OA patients and healthy controls and were positively correlated with inflammation markers and the extent of RA disease activity. In the knees of mice, blockade of the ox-LDL-LOX-1 interaction suppressed arthritic changes and reduced the expression of MMP-3 induced by ox-LDL. CONCLUSION: These findings strongly indicate that sLOX-1 is a novel biomarker that may be useful for the diagnosis of RA and for the evaluation of disease activity in RA. Furthermore, the results suggest that LOX-1 may be a potent therapeutic target for RA.

Nuclear factor-κB activation by type II collagen peptide in articular chondrocytes: its inhibition by hyaluronan via the receptors.

OBJECTIVE: This study aimed to examine nuclear factor-κB (NF-κB) activation by a synthetic peptide from type II collagen fragment (CB12-II) and its inhibition by hyaluronan (HA) via its receptors, CD44, and intercellular adhesion molecule-1 (ICAM-1) in chondrocytes. METHODS: Osteoarthritic cartilage explants or chondrocytes in monolayer were cultured with CB12-II. Secreted levels of matrix metalloproteinase (MMP)-13 in conditioned media and NF-κB activation in chondrocytes were determined by immunoblotting and enzyme-linked immunosorbent assay (ELISA). Cultures were pretreated with HA to evaluate the inhibitory effect on CB12-II action, and the role of HA receptors in HA effect was investigated using antibodies to CD44 and ICAM-1. RESULTS: CB12-II stimulated phosphorylation and nuclear translocation of NF-κB, leading to increased MMP-13 production. HA suppressed NF-κB activation and MMP-13 induction by CB12-II. The individual antibody to CD44 or ICAM-1 partially reversed HA effect on CB12-II action, and both antibodies in combination completely blocked the HA effect. CONCLUSIONS: This study clearly demonstrates that CB12-II activates NF-κB for MMP-13 induction and that HA inhibits CB12-II action through interaction with CD44 and ICAM-1 in chondrocytes. HA administration into osteoarthritic joints could suppress the catabolic action of matrix degradation products such as CB12-II as a potent NF-κB inhibitor.

[Induction of allergic reactions by anticancer drugs in outpatient chemotherapy].

We must understand the conditions during the onset of allergic reactions induced by anticancer drugs in order to respond with an appropriate treatment. We have therefore conducted this study, focusing on allergic reactions induced by each anticancer drug used in outpatient chemotherapy. Allergic reactions occurred in a total of 3.9% (76 cases), most of which were induced by platinum and taxane anticancer drugs. The number of administrations at symptom onset and the times of onset for platinums and taxanes were 11. 7±1. 3 times and 43. 3±4. 8 minutes for platinum; and 2. 3±0. 5 times and 18. 1± 3. 6 minutes for taxanes, respectively. This demonstrated a significant difference between these two drugs(both were p< 0. 01). In terms of re-administration following the onset of allergic reactions, 21 cases(72. 4%)out of 29 cases(38. 2%) were able to continue the administration of suspected drugs. We studied various factors surrounding the possibility of continued administration to two groups which were or were not able to continue receiving treatment. No significant differences were observed between the groups. For continuous safe treatment, it is necessary to understand the characteristics of allergic reactions induced by each anticancer drug. It is also advisable to consider possible precautions(by introducing prevention regimens)and appropriate measures at the time of re-administration, following the onset of allergic reactions.

[Continuation of chemotherapy with bevacizumab for advanced and recurrent colorectal cancer].

We evaluated the association between the number of treatment courses with the concomitant use of bevacizumab(BV) and the reasons for discontinuation of the regimen in patients who received FOLFOX with or without BV as first-line chemotherapy and FOLFIRI with or without BV as second-line chemotherapy for advanced and recurrent colorectal cancer. In first-line treatment, 12 (2-46) and 10 (2-60) treatment courses were administered with and without BV, respectively, and this difference was not significant (p=0.60). In second-line treatment after first-line treatment with the concomitant use of BV, 11 (1-23) and 3 (1-12) treatment courses were administered with and without BV, respectively, and this difference was significant (p<0.01). Discontinuation due to adverse reactions was more frequent for first-line treatment (34.9%) than for second-line treatment (6.2%; p<0.01). The reasons for discontinuation due to adverse reactions during first-line treatment with BV were often associated with BV, and those during first-line treatment without BV were most often associated with peripheral neuropathy. Therefore, we conclude that early detection and prevention of adverse reactions are important in first-line treatment and that pharmacists as well should be involved in the monitoring and management of adverse reactions, although continued administration of BV even during second-line treatment after first-line treatment with BV is recommended.

Preoperative Lower-Limb Muscle Predictors for Gait Speed Improvement after Total Hip Arthroplasty for Patients with Osteoarthritis.

This study aimed to identify preoperative lower-limb muscle predictors for gait speed improvement after total hip arthroplasty (THA) with hip osteoarthritis. Gait speed improvement was evaluated as the subtraction of preoperative speed from postoperative speed. The preoperative muscle composition of ipsilateral hip abductors was evaluated using computed tomography. The females (n = 45) showed smaller total cross-sectional areas of the gluteal muscles than the males (n = 13). The gluteus maximus in the females showed lower lean muscle mass area (LMM) and higher ratios of the intramuscular fat area and the intramuscular adipose tissue area to the total muscle area (TM) than the males. Regression analysis revealed that LMM/TM of the glutei medius and minimus may correlate negatively with postoperative improvement in gait speed. Receiver operating characteristic curve analysis for prediction of minimum clinically important improvement in gait speed at ≥0.32 m/s resulted in the highest area under the curve for TM in the upper portion of the gluteus maximus with negative correlation. The explanatory variables of hip abductor muscle composition predicted gait speed improvement after THA more precisely in the females compared with the total group of both sexes. Preoperative muscle composition should be evaluated separately based on sex for the achievement of clinically important improvement in gait speed after THA.

Risk Factors for the Incidence of the Volar Lunate Facet Fragments in Distal Radius Fractures.

Background The volar lip of the distal radius is the key structure for wrist joint stability. Rigid fixation of the volar lunate facet (VLF) fragment is difficult because of its unique anatomy, and a high rate of postoperative displacement was demonstrated. Purposes The aim of the study is to identify risk factors for VLF in distal radius fractures (DRFs) and to reconsider the important point for primary fixation. Patients and Methods One hundred fifty-five patients who underwent open reduction and internal fixation for an DRF were included and classified into one of the following two groups: VLF(+)or VLF(-). Demographic data, including age, sex, body mass index (BMI), laterality, trauma mechanism, and AO Foundation/Orthopaedic Trauma Association (AO/OTA) classification were recorded. Several parameters were investigated using wrist radiographs of the uninjured side and computed tomography scans of the injured side. Univariate and multivariate logistic regression analyses were performed to evaluate the risk factors for VLF. Results There were 25 patients in the VLF(+) group and 130 patients in the VLF(-) group. The incidence of VLF was 16.1%. The VLF(+) group tended to have a higher BMI and higher energy trauma mechanism. The odds ratio for the sigmoid notch angle (SNA), volar tilt (VT), and lunate facet curvature radius (LFCR) were 0.84, 1.32, and 0.70, respectively, with multivariate analysis, which was significant. A smaller SNA, larger VT, and smaller LFCR are potential risk factors for VLF. Conclusion Over-reduction of the VT at primary fixation should be avoided because it could place an excess burden on the VLF and cause subsequent postoperative fixation failure and volar carpal subluxation. Level of Evidence IV.

Risk Factors for Reintubation After Anterior Cervical Spine Surgery: Comparative Study of Patients With Cervical Spine Trauma and Patients With Cervical Degenerative Disease.

STUDY DESIGN: Single-center retrospective study. OBJECTIVES: The aim was to compare the postoperative outcomes of anterior cervical spine surgery (ACSS) in patients with and without cervical spine trauma. SUMMARY OF BACKGROUND: Few papers have addressed airway obstruction after anterior ACSS for patients with cervical spine trauma. This study aimed to compare airway obstruction after ACSS between patients with cervical degenerative disorders and cervical spine injuries and identify the risk factors for unplanned postoperative reintubation. MATERIALS AND METHODS: Seventy-seven patients who underwent ACSS were enrolled in this retrospective study. There were 52 men and 25 women, with a mean age of 60.3±15.5 years old. The causes of surgery were as follows: 24 cervical spine fractures or dislocations, 12 spinal cord injuries without bony fracture, 19 disc herniations, and 22 myelopathies. The patients' characteristics, operative data, and risk factors for unplanned reintubation within 5 days postoperatively were analyzed using medical records. RESULTS: Postoperative reintubation was performed in 3 patients (3.9%), all of whom suffered trauma. We further examined risk factors for reintubation in patients in the trauma group. There was no significant difference between the reintubation (R) and nonreintubation (non-R) groups in age, sex, body mass index, amount of blood loss and operation time, preoperative paralysis severity, and the number of fused segments. Patients in group R had significantly higher rates of severe anterior element injury (100% vs. 27.3%, P=0.0011). Airway obstruction due to laryngopharyngeal edema and swelling was confirmed by laryngoscopy and computed tomography images. CONCLUSIONS: Unplanned reintubation after ACSS occurred at a higher rate in trauma patients than in patients with degenerative disorders. Our results suggested that the severe damage to the anterior element of the cervical spine was associated with postoperative reintubation. EVIDENCE LEVEL: Level IV.

Synovial joint formation requires local Ext1 expression and heparan sulfate production in developing mouse embryo limbs and spine.

Heparan sulfate proteoglycans (HSPGs) regulate a number of major developmental processes, but their roles in synovial joint formation remain unknown. Here we created conditional mouse embryo mutants lacking Ext1 in developing joints by mating Ext1(f/f) and Gdf5-Cre mice. Ext1 encodes a subunit of the Ext1/Ext2 Golgi-associated protein complex responsible for heparan sulfate (HS) synthesis. The proximal limb joints did form in the Gdf5-Cre;Ext1(f/f) mutants, but contained an uneven articulating superficial zone that expressed very low lubricin levels. The underlying cartilaginous epiphysis was deranged as well and displayed random patterns of cell proliferation and matrillin-1 and collagen IIA expression, indicative of an aberrant phenotypic definition of the epiphysis itself. Digit joints were even more affected, lacked a distinct mesenchymal interzone and were often fused likely as a result of local abnormal BMP and hedgehog activity and signaling. Interestingly, overall growth and lengthening of long bones were also delayed in the mutants. To test whether Ext1 function is needed for joint formation at other sites, we examined the spine. Indeed, entire intervertebral discs, normally composed by nucleus pulposus surrounded by the annulus fibrosus, were often missing in Gdf5-Cre;Ext1(f/f) mice. When disc remnants were present, they displayed aberrant organization and defective joint marker expression. Similar intervertebral joint defects and fusions occurred in Col2-Cre;ß-catenin(f/f) mutants. The study provides novel evidence that local Ext1 expression and HS production are needed to maintain the phenotype and function of joint-forming cells and coordinate local signaling by BMP, hedgehog and Wnt/ß-catenin pathways. The data indicate also that defects in joint formation reverberate on, and delay, overall long bone growth.

Activation of p38 Mitogen-Activated Protein Kinase Is Inhibited by Hyaluronan via Intercellular Adhesion Molecule-1 in Articular Chondrocytes Stimulated With Type II Collagen Peptide.

This study examined the activation of p38 mitogen-activated protein kinase with matrix metalloproteinase-13 (MMP-13) production by a synthetic peptide derived from type II collagen (CB12-II) and its inhibition by high molecular weight hyaluronan (HA) in chondrocytes. When cartilage explants or isolated chondrocytes in monolayer were incubated with CB12-II, the peptide (50 µM, 72 h) activated p38 in association with enhanced MMP-13 production. Inhibition studies with SB203580 (0.1 - 1 µM) indicated the requirement of p38 for CB12-II-induced MMP-13 production. Pretreatment with 2700 kDa HA (1 mg/ml, 1 h) resulted in significant suppression of CB12-II-stimulated MMP-13 production in cartilage as well as in chondrocyte monolayer cultures. HA (1 mg/ml) suppressed p38 activation by CB12-II, leading to a decrease in MMP-13 production. The antibody (20 µg/ml) to intercellular adhesion molecule-1 (ICAM-1), which has been recognized as a receptor of HA on chondrocytes, reversed the HA effect on CB12-II action. Thus, the present study clearly demonstrated that high molecular weight HA suppressed CB12-II-activated p38 via ICAM-1 in articular chondrocytes. HA could down-regulate the catabolic action of type II collagen fragments in osteoarthritic joints through the mechanism demonstrated in this study.

Activation of p38 mitogen-activated protein kinase is inhibited by hyaluronan via intercellular adhesion molecule-1 in articular chondrocytes stimulated with type II collagen peptide.

This study examined the activation of p38 mitogen-activated protein kinase with matrix metalloproteinase-13 (MMP-13) production by a synthetic peptide derived from type II collagen (CB12-II) and its inhibition by high molecular weight hyaluronan (HA) in chondrocytes. When cartilage explants or isolated chondrocytes in monolayer were incubated with CB12-II, the peptide (50 µM, 72 h) activated p38 in association with enhanced MMP-13 production. Inhibition studies with SB203580 (0.1 - 1 µM) indicated the requirement of p38 for CB12-II-induced MMP-13 production. Pretreatment with 2700 kDa HA (1 mg/ml, 1 h) resulted in significant suppression of CB12-II-stimulated MMP-13 production in cartilage as well as in chondrocyte monolayer cultures. HA (1 mg/ml) suppressed p38 activation by CB12-II, leading to a decrease in MMP-13 production. The antibody (20 µg/ml) to intercellular adhesion molecule-1 (ICAM-1), which has been recognized as a receptor of HA on chondrocytes, reversed the HA effect on CB12-II action. Thus, the present study clearly demonstrated that high molecular weight HA suppressed CB12-II-activated p38 via ICAM-1 in articular chondrocytes. HA could down-regulate the catabolic action of type II collagen fragments in osteoarthritic joints through the mechanism demonstrated in this study.