Risk factors for nonunion in femoral neck fracture patients with internal fixation: A multicenter (TRON group) retrospective study.

INTRODUCTION: Femoral neck fractures (FNFs) are common in elderly individuals. When minimally displaced, they are typically treated with internal fixation. Nonunion is a complication of internal fixation of FNF, that sometimes necessitates reoperation. Radiographic parameters, including the Pauwels angle and posterior tilt angle, are risk factors for nonunion. However, these parameters are assessed solely in a two-dimensional context. We developed a novel radiographic parameter named the "Kindex." This multicenter investigation aimed to identify risk factors for nonunion following FNF fixation and evaluate the validity of this index. METHODS: This retrospective multicenter study collected data from 939 FNF patients who underwent internal fixation between 2016 and 2020 at 11 facilities (TRON group). The following exclusion criteria were applied: age <65, insufficient data, and Garden Stage III or IV fracture. Patient data, including age, sex, BMI, ASA classification, alcohol and smoking history, and comorbidities, were recorded. Radiographic measurements of the Pauwels angle and posterior tilt angle at the time of injury were used to calculate the Kindex. Correlations between the Pauwels angle, posterior tilt angle, Kindex, and nonunion were evaluated. A multivariate logistic regression analysis was performed to investigate independent risk factors for nonunion. A receiver operating characteristic (ROC) analysis was performed to determine the cutoff value of the Kindex, and the area under the curve (AUC) was calculated. RESULTS: The study included 594 patients (males, n = 151; females, n = 443; average age, 80.9 years). Nonunion was observed in 13 cases (2.2 %). While the Pauwels angle and posterior tilt angle did not show significant correlations, the Kindex exhibited strong correlations with both parameters. In the multivariate analysis, the Kindex and renal impairment were independent risk factors for nonunion (Kindex: OR 1.06, p = 0.015; renal impairment: OR 1.48, p = 0.021). In the ROC analysis, a Kindex of 50 was identified as the optimal cutoff value (AUC 0.72). CONCLUSION: The nonunion rate after internal fixation of FNF was 2.2 %. Renal impairment and the Kindex were identified as independent risk factors. The Kindex at the time of injury may serve as a novel radiographic parameter to consider when evaluating the need for internal fixation in FNF cases.

Elderly trochanteric fracture outcomes: Unveiling the risks of excessive postoperative sliding - A retrospective multicenter (TRON group) investigation.

BACKGROUND: Intramedullary nailing (IMN) for femoral trochanteric fractures (FTF) is the primary surgical intervention. Excessive lag screw sliding (ES) of the femoral neck screw sometimes occurs. This multicenter investigation sought to 1) determine the prevalence of ES, 2) evaluate the relationship between ES and postoperative complications, and 3) identify the factors of ES in elderly patients with FTF undergoing IMN. METHODS: From 2016 to 2020, 1448 patients with FTF were treated using a short IMN across 11 institutions (TRON group). Upon applying exclusion criteria, 519 patients (127 men, 392 women; mean age, 84.4 years) were included. The postoperative sliding distance was measured immediately after surgery and at final follow-up. A sliding distance of ≥8 mm categorized patients as having ES. We identify the factors contributing to ES using the logistic regression analysis, with a p < 0.05 as statistical significance. RESULTS: ES was observed in 116 patients (22.4 %). Patients with ES had a higher incidence of postoperative cut-out and peri-implant fracture. Logistic regression analysis showed that achieving optimal reduction in both AP and lateral views (odds ratio (OR) 0.48, p = 0.0012) and the use of a double screw system or twin screws with integrated locking mechanism significantly reduced the risk of ES (OR 0.27, 0.17; p = 0.0027, <0.001). CONCLUSIONS: The incidence rate of ES was 22.4 %. ES was associated with a higher risk of postoperative complications. The surgeons should aim for optimal reduction and use a double screw or twin screws with an integrated interlocking mechanism as the implant of choice.

Accelerometer-based portable navigation system shows no superior accuracy over pelvic alignment guide for acetabular cup placement in total hip arthroplasty in lateral decubitus position.

BACKGROUND: Total hip arthroplasty (THA) using a portable navigation system (PNS) incurs costs per procedure. However, it does not require a large console. This study aimed to compare the accuracy of acetabular cup placement using a pelvic alignment guide (PAG) attached to the pelvis and an accelerometer-based PNS in THA performed in the lateral decubitus position. METHODS: We retrospectively analyzed 100 hips that underwent primary THA in the lateral decubitus position between July 2018 and January 2021. The PAG was used in 50 hips, whereas the PNS was used in the other 50. Cup placement accuracy was measured using postoperative computed tomography scans, comparing errors in inclination and anteversion angles. The surgical time, blood loss, and complications were recorded. The follow-up period was at least 2 years in all cases. RESULTS: The mean absolute error of the inclination angle was similar between the groups (the PAG group: 3.7° ± 2.3° [range, 0.0-9.0]; the PNS group: 3.7° ± 2.3° [range, 0.2-10.5], p = 0.705). The mean absolute error of the anteversion angle was significantly smaller in the PAG group than in the PNS group (3.0° ± 2.4° [range, 0.0-9.7] vs. 6.5° ± 4.8° [range, 0.3-17.3], p < 0.001). The PAG group had a higher proportion of hips within 5° and 10° of the target angle (64 vs. 42%, P = 0.028, and 100 vs. 74%, p < 0.001, respectively). The PNS group had six hips with anteversion errors of 15° or more. Surgical time and blood loss were lower in the PAG group. The PNS group had one dislocation, whereas the PAG group did not. CONCLUSION: The accelerometer-based PNS did not demonstrate superior cup alignment accuracy compared to the PAG in THA performed in the lateral decubitus position. This finding informs surgeons that computer-assisted surgery is not necessarily superior to conventional THA using a PAG.

Risk factors for residual pelvic obliquity one year after total hip arthroplasty.

PURPOSE: It is not uncommon for patients with hip disorders to present with pelvic obliquity (PO), and residual PO after total hip arthroplasty (THA) may not only affect hip joint function but also cause adjacent intervertebral joint disorders. This study aimed to investigate the postoperative PO impact on clinical outcomes and risk factors by comparing patients who had PO after THA to those who did not. METHODS: A single-center, retrospective cohort study was conducted. A total of 103 patients who underwent THA were included in this study from 2018 to 2020. Demographics, functional outcomes, and spinopelvic parameters were compared between post-THA PO of less than 2° (NT group, 55 patients) and PO of 2° or more (O group, 48 patients). Multivariate analysis was performed using factors with significant differences in univariate analysis. RESULTS: Postoperative Harris Hip Score Activity was significantly lower in the T group than in the NT group (p = 0.031). Preoperative PO was smaller in the NT group than in the T group (p = 0.001). Preoperative lumbar bending range (LBR) was significantly more flexible in the NT group than in the T group. In the logistic regression analysis, Age (odds ratio 0.957, 95% CI 0.923-0.993, p = 0.020), preoperative PO (odds ratio 1.490, 95% CI 1.100-2.020, p = 0.001), and LBR (odds ratio 0.848, 95% CI 0.756-0.951, p = 0.005) were found to be significant factors. CONCLUSION: Younger age and large preoperative PO, and poor lumbar spine mobility were identified as risk factors for residual postoperative PO.

Free bone fragments are associated with the development of heterotopic ossification after hemiarthroplasty for femoral neck fracture: a retrospective observational study.

PURPOSE: Heterotopic ossification (HO) can occur after hemiarthroplasty (HA) for femoral neck fractures (FNF). This study aimed to investigate the frequency and factors contributing to the development of HO after HA. METHODS: The study included data from 92 of 183 patients (26 male and 66 female) who sustained FNF and underwent HA between April 2019 and January 2022. HO was identified on postoperative radiographic images. Patient background, operative duration, blood loss, and presence of free bone fragments immediately after surgery were compared between the HO and non-HO groups. Statistical analyses included the independent-sample t-test for continuous variables and the chi-squared test for categorical variables. A multivariate logistic regression analysis was performed using HO as an objective variable. RESULTS: HO occurred in 50 of the 92 (54%) patients. There were no statistically significant differences in patient backgrounds. Univariate analysis revealed significantly longer mean operative duration and greater blood loss in the HO group. Free bone fragments in the immediate postoperative period were observed in 29 of 50 (58%) patients in the HO group and in 3 of 42 (7.1%) patients in the non-HO group, a statistically significant difference. Logistic regression analysis revealed that the presence of free bone fragments was an independent explanatory factor for HO development. CONCLUSION: The presence of free bone fragments immediately after surgery may be significantly associated with the development of HO. Therefore, it is necessary to sufficiently remove such fragments during surgery because they may trigger HO.

Characteristics of pelvic obliquity in dysplastic hip osteoarthritis.

PURPOSE: Factors affecting direction of pelvic obliquity (PO) in dysplastic hip osteoarthritis (DHOA) remains unclear. This retrospective cohort study evaluates morphological characteristics, spinal alignment, and hip function in patients with unilateral DHOA. METHODS: Between 2018 and 2022, 104 patients with unilateral DHA were enrolled. Patients were categorized into flat PO (F-PO group; PO < 2°), affected side PO (A-PO group; PO downward by ≥ 2°), and unaffected side PO (U-PO group; PO upward by ≥ 2°). Demographics, radiographic hip and lower limb parameters, spinal parameters, and functional scores were compared between the groups. RESULTS: There were 39, 44, and 21 patients in the F-PO, A-PO, and U-PO group, respectively. The subluxation percentage of Crowe classification showed a significant difference among the three groups. The femoral head lateralization distance was significantly greater in the U-PO group than in the F-PO and A-PO groups. Furthermore, the hip adduction angle was significantly lower in the A-PO group than in the F-PO and U-PO groups. The lumbar scoliosis angle was significantly different between the groups. In multivariate analysis, hip adduction angle was extracted as an independent factor associated with the A-PO. Age, subluxation percentage, and hip adduction angle were identified as independent factors associated with the U-PO. Harris hip score was significantly poorer in U-PO group than in F-PO group. CONCLUSIONS: Hip adduction angle influenced A-PO, while age, subluxation percentage, and hip adduction angle influenced U-PO; lumbar scoliosis angle was associated with PO direction. U-PO patients had poorer functional scores, indicating the impact of hip contracture and subluxation on PO direction in DHOA.

Peri-implant fractures after Intramedullary fixation for femoral trochanteric fracture: a multicenter (TRON Group) study.

BACKGROUND: With the rise in elderly populations, the incidence of femoral trochanteric fractures has also increased. Although intramedullary nail therapy is commonly used, the incidence of peri-implant fractures (PIFs) as a complication and its associated factors are not fully understood. The purpose of this study was to determine the incidence of PIFs and treatment strategies and outcomes. METHODS: A retrospective study across 11 hospitals from 2016 to 2020 examined 1855 patients with femoral trochanter fracture. After excluding 69 patients treated without intramedullary nailing, 1786 patients were analyzed. Parameters studied included age, sex, body mass index, medical history, and treatment methods. PIFs were categorized using the Chan classification. Treatment outcomes and patient mobility were assessed using the Parker Mobility Score, and postoperative complications and one-year survival data were compiled. RESULTS: The incidence of PIFs was 8 in 1786 cases. Chan classification showed 1 case of N1A, 6 of N2A, and 1 of N2B. Only the type N1 case was a transverse fracture, whereas all cases of type N2 were oblique fractures. Among these cases, five patients had fractures extending to the upper part of the femoral condyle. The patient with N1A and one bedridden patient with N2A fracture underwent conservative treatment, one patient with N2A in which the fracture did not extend to the condyle was treated with nail replacement, and 5 patients (N2A: 4, N2B: 1) with fractures extending to the condyle were treated with additional plate fixation. All patients had survived at one year after treatment for PIF, and no reoperations were required. CONCLUSIONS: The incidence of PIF was very low (0.45%). Of the 6 PIF cases, excluding the bedridden patients, the treatment of choice for PIF was an additional plate if the fracture line extended to the femoral condyle; otherwise, the nail was replaced. All patients achieved bony fusion. LEVEL OF EVIDENCE: Therapeutic Level IV.

Relationship between locomotive syndrome and advanced glycation end products measured by skin autofluorescence in community-dwelling patients: the Yakumo Study.

Advanced glycation end products (AGEs) have been reported to be associated with osteoporosis, aging, sarcopenia, and frailty. This study aimed to investigate the association AGEs with locomotive syndrome (LS). Participants were Japanese individuals aged 39 years or older who participated in the Yakumo Study (n=230). AGEs were measured by skin autofluorescence (SAF) using an AGE reader. We investigated SAF values for each locomotive stage. Multivariate logistic regression models were used to calculate the odds ratios of LS-associated factors. The relationships between SAF and physical performance and bone mineral density (BMD) were investigated. A receiver operating characteristic (ROC) curves were generated to determine the optimal cut-off value of SAF for predicting LS. SAF values tended to increase correspondingly with LS severity. SAF was an independently explanatory factor for LS (odds ratio 2.70; 95% confidence interval [CI] 1.040-6.990). SAF was positively correlated with the 10-m walking speed, The Timed Up and Go test results, and was negatively correlated with BMD. ROC curve represented by SAF for the presence or absence of LS risk had an area under the curve of 0.648 (95% CI: 0.571-0.726). High SAF values were identified as an independent risk factor for LS. AGEs could be a potential screening tool for people for LS.

Analysis of Calcaneal Avulsion Fractures Treated Surgically and Nonsurgically: A Retrospective Multicenter Study.

Background: Calcaneal avulsion fractures (CAvFs) at the Achilles tendon insertion are among the more challenging fractures to treat. Although rare, they often require reoperation. The optimal treatment, including nonsurgical procedures and better implants for surgical procedures in the treatment of CAvFs, remains to be established. Therefore, our study aimed to (1) perform a descriptive evaluation of CAvFs, including cases managed nonsurgically, and (2) assess surgical procedures, including the incidence of complications and reoperation for surgically treated CAvFs. Methods: In this multicenter retrospective study, we collected data of patients with CAvFs treated at 9 hospitals from 2012 to 2022. We performed a descriptive study of CAvFs and compared postoperative complications and reoperation rates for multiple surgical techniques and implants. The size of the bone fragments was quantified. Results: The data of 70 patients with CAvFs were analyzed; 20 patients were treated nonsurgically, and 50 were treated surgically. The mean age of patients was 68.5 years; 67% of the patients were female. Nineteen percent of the patients had diabetes, and 19% had osteoporosis. The incidence of postoperative complications was 30%, with infection in 14%, necrosis in 26%, and loss of reduction in 18%. The reoperation rate was 22%. Surgical techniques with use of cannulated cancellous screws were performed in 80% of the surgical cases. Cannulated cancellous screw (CCS) fixation alone resulted in a reoperation rate of 35%, whereas additional augmentation, including washers with CCS fixation, resulted in a reoperation rate of 10%. CCS fixation was successfully performed, although suture anchors were used in some cases with smaller fragments. Conclusions: CAvFs occurred more frequently in older women and had a high rate of postoperative complications. A combination of CCS with augmentation was more effective at reducing postoperative complications than CCS fixation alone, even when the bone fragment size was small. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

What Are the Sex-Based Differences of Acetabular Coverage Features in Hip Dysplasia?

BACKGROUND: Eccentric rotational acetabular osteotomy is performed to prevent osteoarthritis caused by developmental dysplasia of the hip (DDH). To achieve sufficient acetabular coverage, understanding the characteristics of acetabular coverage in DDH is necessary. However, the features of acetabular coverage in males with DDH remain unclear. We thought that the differences in acetabular coverage between females and males might be associated with the differences in pelvic morphology between the sexes. QUESTIONS/PURPOSES: (1) What are the differences in the acetabular coverage between females and males with DDH? (2) What are the differences in the rotations of the ilium and ischium between females and males with DDH? (3) What is the relationship between the rotation of the ilium and ischium and the acetabular coverage at each height in females and males with DDH? METHODS: Between 2016 and 2023, 114 patients (138 hips) underwent eccentric rotational acetabular osteotomy at our hospital. We excluded patients with Tönnis Grade 2 or higher, a lateral center-edge angle of 25º or more, and deformities of the pelvis or femur, resulting in 100 patients (122 hips) being included. For female patients (98 hips), the median (range) age was 40 years (10 to 58), and for the male patients (24 hips), it was 31 years (14 to 53). We used all patients' preoperative AP radiographs and CT data. The crossover sign, posterior wall sign, and pelvic width index were evaluated in AP radiographs. The rotation of the innominate bone in the axial plane was evaluated at two different heights, specifically at the slice passing through the anterior superior iliac spine and the slice through the pubic symphysis and ischial spine in CT data. Furthermore, we evaluated the anterior and posterior acetabular sector angles. Comparisons of variables related to innominate bone measurements and acetabular coverage measurements between females and males in each patient were performed. The correlations between pelvic morphology measurements and acetabular coverage were evaluated separately for females and males, and the results were subsequently compared to identify any sex-specific differences. For continuous variables, we used the Student t-test; for binary variables, we used the Fisher exact test. A p value less than 0.05 was considered statistically significant. RESULTS: In the evaluation of AP radiographs, an indicator of acetabular retroversion-the crossover sign-showed no differences between the sexes, whereas the posterior wall sign (females 46% [45 of 98] hips versus males 75% [18 of 24] hips, OR 3.50 [95% confidence interval (CI) 1.20 to 11.71]; p = 0.01) and pelvic width index less than 56% (females 1% [1 of 98] versus males 17% [4 of 24], OR 18.71 [95% CI 1.74 to 958.90]; p = 0.005) occurred more frequently in males than in females. There were no differences in the iliac rotation parameters, but the ischium showed more external rotation in males (females 30° ± 2° versus males 24° ± 1°; p < 0.001). Regarding acetabular coverage, no differences between females and males were observed in the anterior acetabular sector angles. In contrast, males showed smaller values than females for the posterior acetabular sector angles (85° ± 9° versus 91° ± 7°; p = 0.002). In females, a correlation was observed between iliac rotation and acetabular sector angles (anterior acetabular sector angles: r = -0.35 [95% CI -0.05 to 0.16]; p < 0.001, posterior acetabular sector angles: r = 0.42 [95% CI 0.24 to 0.57]; p < 0.001). Similarly, ischial rotation showed a correlation with both acetabular sector angles (anterior acetabular sector angles: r = -0.34 [95% CI -0.51 to -0.15]; p < 0.001 and posterior acetabular sector angles: r = 0.45 [95% CI 0.27 to 0.59]; p < 0.001). Thus, in females, we observed that external iliac rotation and ischial internal rotation correlated with increased anterior acetabular coverage and reduced posterior coverage. In contrast, although acetabular coverage in males showed a correlation with iliac rotation (anterior acetabular sector angles: r = -0.55 [95% CI -0.78 to -0.18]; p = 0.006 and posterior acetabular sector angles: r = 0.74 [95% CI 0.48 to 0.88]; p < 0.001), no correlation was observed with ischial rotation. CONCLUSION: In males, acetabular retroversion occurs more commonly than in females and is attributed to their reduced posterior acetabular coverage. In females, an increase in the posterior acetabular coverage was correlated with the external rotation angle of the ischium, whereas in males, no correlation was found between ischial rotation and posterior acetabular coverage. In treating males with DDH via eccentric rotational acetabular osteotomy, it is essential to adjust bone fragments to prevent inadequate posterior acetabular coverage. Future studies might need to investigate the differences in acetabular coverage between males and females in various limb positions and consider the direction of bone fragment rotation. CLINICAL RELEVANCE: Our findings suggest that males with DDH exhibit acetabular retroversion more frequently than females, which is attributed to the reduced posterior acetabular coverage observed in males. The smaller posterior acetabular coverage in males might be related to differences in ischial morphology between sexes. During eccentric rotational acetabular osteotomy for males with DDH, adequately rotating acetabular bone fragments might be beneficial to compensate for deficient posterior acetabular coverage.

Preoperative Sarcopenia Severity and Clinical Outcomes after Total Hip Arthroplasty.

The outcome of total hip arthroplasty (THA) in patients with end-stage arthritis of the hip is associated with preoperative physical status. This study was performed to examine the relationship between the preoperative severity of sarcopenia and clinical outcomes after THA. This retrospective cohort study was performed among 306 consecutive patients (mean age: 63.7 ± 12.9 years, 222 women) undergoing THA at a university hospital. The severity of sarcopenia was determined based on the skeletal muscle mass index (SMI), handgrip strength, and gait speed according to the criteria of the Asian Working Group for Sarcopenia 2019. The severe sarcopenia prevalence rate was 10.6%. Severe sarcopenia was significantly associated with the risk of delayed functional recovery (adjusted odds ratio, 2.82; 95% confidence interval, 1.03-7.72; p = 0.043) compared with the non-sarcopenia group after adjusting for pre-existing risk factors, including preoperative hip function and physical activity. The addition of SMI, handgrip strength, and gait speed to the model for risk of functional recovery delay significantly increased the area under the receiver operating characteristic curve (p = 0.038). Severe sarcopenia was significantly associated with poorer hip function and patient-reported outcomes at 6 months after surgery compared with the non-sarcopenia group. Severe sarcopenia was adversely associated with postoperative clinical outcomes in patients undergoing THA.

Descriptive analysis of incidence and risk factors for short intramedullary nail breakage in femoral intertrochanteric fractures: a multicenter (TRON group) retrospective study.

BACKGROUND: The incidence of hip fractures is increasing. Femoral intertrochanteric fractures make up 50% of hip fractures and are treated by intramedullary nails. Implant breakage is a recognized complication that can have rare and serious implications. This study aimed to investigate implant breakage rates after surgical treatment for femoral intertrochanteric fractures. METHODS: This was a retrospective multicenter analysis. All 1854 patients who underwent surgical treatment for femoral intertrochanteric fractures were selected from 12 hospitals (TRON group) between 2016 and 2020. Exclusion criteria included implants other than those specified and follow-up periods less than three months. Demographic data, surgical details, and radiographic assessments were collected from medical records and X-ray evaluations. RESULTS: Among the 983 study patients, consisting of 245 males (24.9%) and 738 females (75.1%), the implant breakage rate was 0.31%, with three confirmed cases. The average age was 83.9 years. The mean follow-up period was 640.9 days. Two cases were linked to ASULOCK implants, and one to an OLSII implant. Statistical analysis showed a significantly higher incidence of ASULOCK implant breakage (p < 0.001). In the two cases of ASULOCK implant breakage and one case of OLSII implant breakage, breakage in all three implants occurred at the anti-rotation screws. CONCLUSIONS: There were no implant breakages of the main body of the implants; all breakages occurred in the additional anti-rotation screw. The necessity of the anti-rotation screw will require further discussion. These results can potentially inform clinical decisions and guide further research in preventing implant breakage.

Factors related to collapse progression in Japanese Investigation Committee classification type B osteonecrosis of the femoral head.

PURPOSE: This study aimed to identify factors related to collapse progression in Japanese Investigation Committee classification type B osteonecrosis of the femoral head (ONFH) and to identify patients who would benefit from surgical treatment. METHODS: This study included 41 patients (56 hips) with type B ONFH with a minimum follow-up of three years. Based on a ≥ 3 mm collapse progression in ONFH, we categorised patients into two groups: collapse progression and no collapse progression. Sagittal and coronal computed tomography images were used to measure the necrotic region relative to the intact femoral head diameter. The ratios of the necrotic regions of transverse and vertical diameter in coronal and sagittal images are defined as mediolateral transverse and mediolateral vertical, anteroposterior transverse and anteroposterior vertical, respectively. Demographic data and these imaging findings were compared between the two groups. We established a cut-off value for predicting collapse progression through receiver operating characteristic analysis and determined survival rates. RESULTS: Type B ONFH had a 17.8% collapse progression rate. The mediolateral transverse, mediolateral vertical, anteroposterior transverse, and anteroposterior vertical were significantly higher in the collapse progression group (P < 0.01). Mediolateral transverse was an independent risk factor of collapse progression (hazard ratio, 1.27; 95% confidence interval, 1.03-1.57; P = 0.03), with an optimal cut-off of 45.6%. The 5-year survival rates with collapse progression as the endpoints were 57.0 and 94.9% in the mediolateral transverse of ≥ 45.6 and < 45.6%, respectively. CONCLUSION: A mediolateral transverse of ≥ 45.6% predicts collapse progression in patients with type B ONFH.

Retrospective study comparing the accuracies of handheld infrared stereo camera and augmented reality-based navigation systems for total hip arthroplasty.

BACKGROUND: The use of portable navigation systems (PNS) in total hip arthroplasty (THA) has become increasingly prevalent, with second-generation PNS (sPNS) demonstrating superior accuracy in the lateral decubitus position compared to first-generation PNS. However, few studies have compared different types of sPNS. This study retrospectively compares the accuracy and clinical outcomes of two different types of sPNS instruments in patients undergoing THA. METHODS: A total of 158 eligible patients who underwent THA at a single institution between 2019 and 2022 were enrolled in the study, including 89 who used an accelerometer-based PNS with handheld infrared stereo cameras in the Naviswiss group (group N) and 69 who used an augmented reality (AR)-based PNS in the AR-Hip group (group A). Accuracy error, navigation error, clinical outcomes, and preparation time were compared between the two groups. RESULTS: Accuracy errors for Inclination were comparable between group N (3.5° ± 3.0°) and group A (3.5° ± 3.1°) (p = 0.92). Accuracy errors for anteversion were comparable between group N (4.1° ± 3.1°) and group A (4.5° ± 4.0°) (p = 0.57). The navigation errors for inclination (group N: 2.9° ± 2.7°, group A: 3.0° ± 3.2°) and anteversion (group N: 4.3° ± 3.5°, group A: 4.3° ± 4.1°) were comparable between the groups (p = 0.86 and 0.94, respectively). The preparation time was shorter in group A than in group N (p = 0.036). There were no significant differences in operative time (p = 0.255), intraoperative blood loss (p = 0.387), or complications (p = 0.248) between the two groups. CONCLUSION: An Accelerometer-based PNS using handheld infrared stereo cameras and AR-based PNS provide similar accuracy during THA in the lateral decubitus position, with a mean error of 3°-4° for both inclination and anteversion, though the AR-based PNS required a shorter preparation time.

Early surgery within 48 hours of admission for hip fracture did not improve 1-year mortality in Japan: a single-institution cohort study.

INTRODUCTION: Early surgery for hip fracture, within 48 hours of hospital admission, is effective in reducing mortality. However, the average preoperative waiting time for hip fractures in Japan is 4.5 days and the 1-year mortality rate after a hip fracture is 10% in Japan. This study aimed to investigate whether early surgery, within 48 hours, could reduce the 1-year mortality rate in patients with hip fractures in Japan. METHODS: This cohort study involved 402 consecutive patients with hip fractures who underwent surgical treatment between January 2013 and September 2019. The exclusion criteria were an age of <60 years and in-hospital injury. A total of 389 patients were included in this study. The patients were divided into two groups: those who underwent early surgery within 48 hours of admission (early group) and those who di not undergo early surgery (delayed group). We compared patient characteristics and treatment outcomes between the 2 groups. RESULTS: A comparison of patient characteristics revealed that the early group had lower hemoglobin levels (P=0.046), lower C-reactive protein levels (P = 0.031), lower numbers of patients with weekend hospitalization, lower numbers of patients with a history of using medications that may cause bleeding (P < 0.01), and who received general anaesthesia (P < 0.01). However, there were no significant differences with regard to the other variables between the 2 groups. A treatment outcome analysis showed that the early group had shorter waiting times for surgery (P < 0.01) and shorter stays in acute-care wards (P < 0.01). However there were no differences in the total hospital stay, Barthel index at discharge, home discharge rates, in-hospital mortality rates, and 1-year mortality. CONCLUSION: Our findings indicate that early surgery did not reduce the 1-year mortality rate in older patients with hip fractures in Japan.

Risk factors of periprosthetic joint infection after hemiarthroplasty for displaced femoral neck fracture in the elderly: Analysis of 1619 cases in the multicenter database.

PURPOSE: This multicenter retrospective study focuses on understanding the incidence, causative bacteria, and risk factors for Periprosthetic Joint Infection (PJI) following hemiarthroplasty in elderly patients with displaced femoral neck fractures (FNF). METHODS: From 2016 to 2020, 1,619 patients were diagnosed with displaced FNFs and treated surgically across 11 centers. After exclusions, 1,438 patients (399 men and 1,039 women) were included in the study, averaging 82.1 years in age and 20.2 kg/m² in BMI, observed over 25.7 months on average. Data on demographics, medical history, surgical details, and complications were described. RESULTS: PJI occurred in 20 of the 1438 patients (1.4%). The causative organism was methicillin-susceptible Staphylococcus aureus in 6 patients and methicillin-resistant S. aureus in 6 patients. In patients' backgrounds, the average age was slightly higher in the non-PJI group (82.1 years) compared to the PJI group (80.4 years). There was a higher percentage of males in the PJI group (45%) than in the non-PJI group (27.5%). Drug history showed that the prevalence of anticoagulant use in the PJI group was 25%. Peripheral vascular disease and diabetes mellitus were more prevalent in the PJI group. Most patients in both groups were independent in daily activities. The blood transfusion rate was significantly higher in the PJI group (50%) than in the non-PJI group (23.8%). Notably, the incidence of hematoma was higher in the PJI group (40%). CONCLUSION: This multicenter retrospective study demonstrates a low incidence (1.4%) of PJI in elderly patients undergoing hemiarthroplasty for FNF, primarily due to Staphylococcus aureus. Increased usage of antiplatelets and anticoagulants, as well as comorbidities related to atherosclerosis, like peripheral vascular disease and diabetes mellitus, were observed in patients with PJI. Additionally, these patients experienced higher rates of blood transfusion and postoperative hematomas, highlighting the need for careful management. It should be noted, however, that this finding is a conclusion limited by study design issues, including the retrospective design, small PJI sample size, and variability in treatment approaches.

Comparison of conjoined tendon-preserving posterior approach and conventional posterolateral approach in hemiarthroplasty for femoral neck fracture in the elderly: A multicenter (TRON group) retrospective study.

BACKGROUND: Femoral neck fractures (FNF) are one of the most common traumatic injuries in the elderly. The conjoined tendon-preserving posterior (CPP) approach was developed as a modification of the conventional posterolateral (PL) approach in hemiarthroplasty (HA) for displaced femoral neck fractures (FNF) to reduce postoperative dislocation. We hypothesized that the CPP approach would result in fewer dislocations and similar functional and radiographic outcomes compared to the PL approach. PATIENTS AND METHODS: This was a retrospective multicenter (TRON group) study. We evaluated the rate of complications, and functional and radiographic outcomes for patients aged >65 years who underwent HA via the PL approach or the CPP approach from 2017 to 2019 and followed up for at least 24 months. To adjust for baseline differences between the groups, a propensity score-matching algorithm was used in a 1:1 ratio. RESULTS: We identified 135 patients who underwent HA via the PL approach and 135 patients via the CPP approach. The mean follow-up period was 32.4 ± 14.0 months. The incidence of dislocation was 6 in 135 patients (4.4%) in the PL group and 0 in 135 patients (0%) in the CPP group, and there was significant difference (p = 0.04). Operation time was equivalent between the two groups (73.1 ± 30.4 vs. 71.8 ± 30.0 min; p = 0.72). The rate of varus insertion of stems in the PL group lower than that in the CPP group (19.3% vs. 33.3%; p = 0.01). Postoperative Parker's mobility score was similar between the two groups at 12 months follow-up (6.17 vs. 6.27; p = 0.81). CONCLUSION: The CPP approach showed a significantly lower dislocation rate, similar functional outcome and more varus stem insertions compared with the PL approach in this retrospective study.

Low and high body mass index and lower numbers of screws in the articular segment are risk factors for non-union of distal humeral fractures in the elderly: A multi-center retrospective study (TRON study).

Background: Distal humerus fracture in the elderly is a challenging fracture for orthopedic surgeons. Non-union is one of the serious complications of distal humerus fracture after surgery. This retrospective multicenter study aimed to estimate the incidence of distal humeral non-union after open reduction and internal fixation, determine factors related to non-union, and compare the postoperative results of cases with non-union to cases with the union. Methods: Among 423 patients diagnosed with distal humeral fracture and who were treated by surgical therapy in 2010-2020 from our database called TRON. Only 190 subjects met the inclusion criteria. We performed a logistic regression analysis with the presence of non-union as the response variable to examine risk factors. We compare the Mayo Elbow Performance Scores of cases with non-union to cases with the union. Results: Non-union occurred after surgery in 15 patients (7.9%). The logistic regression analysis showed that body mass index<20 kg/m2 and ≥25 kg/m2, and ≤3 screws in the articular segment were significant explanatory factors for non-union (odds ratio 10.4 and 47.8, respectively). The Mayo Elbow Performance Scores were significantly worse in patients with non-union. Discussion: Low and high body mass index and three or fewer screws in the articular segment might be risk factors for non-union of distal humerus fracture in the elderly. Non-union is associated with poor clinical outcomes.

Obesity Is Associated with Asymptomatic Vertebral Fractures: A Yakumo Study.

(1) Background: Patients with primary vertebral fracture (VF) are at high risk of re-fracture and mortality. However, approximately two-thirds of patients with VFs receive minimal clinical attention. (2) Methods: The current study aimed to investigate the factors associated with asymptomatic VFs in middle-aged and elderly individuals who underwent resident health examinations. (3) Results: The current study included 217 participants aged > 50 years. VFs were diagnosed based on lateral radiographic images using Genant's semiquantitative (SQ) method. The participants were divided into non-VF (N; SQ grade 0) and asymptomatic VF (F; SQ grades 1-3) groups. Data on body composition, blood tests, quality of life measures, and radiographic parameters were assessed. A total of 195 participants were included in the N group (mean age, 64.8 ± 7.8 years), and 22 were in the F group (mean age, 66.1 ± 7.9 years). The F group had a significantly higher body mass index (BMI), body fat percentage (BF%), and proportion of patients with knee osteoarthritis (KOA) than the N group. The F group had a significantly higher knee joint pain visual analog scale (VAS) score and painDETECT score than the N group. Logistic regression analysis showed that BF% was associated with asymptomatic VFs. (4) Conclusions: Middle-aged and elderly individuals with asymptomatic VF presented with high BMIs, BF%, and incidence of KOA.