Transplantation of embryonic spinal motor neurons into peripheral nerves enables functional reconstruction of a denervated diaphragm.

Respiratory muscle paralysis due to trauma or neurodegenerative diseases can have devastating consequences. Only a few studies have investigated the reconstruction of motor function in denervated diaphragms caused by such conditions. Here, we studied the efficacy of transplanting E14 embryonic spinal motor neurons (SMNs) into peripheral nerve grafts for functionally reconstructing a denervated diaphragm in a rat model. The diaphragms of 8-week-old male Fischer 344 rats were first denervated by transecting the phrenic nerves. Subsequently, peripheral nerve grafts taken from the lower limb were used for neurotization of the denervated diaphragms. One week later, fetal E14 SMNs were transplanted into the peripheral nerve grafts. After 3 months, we observed functional contraction of the diaphragm following neuromuscular electrical stimulation (NMES) of the peripheral nerve graft. Additionally, we confirmed that SMN transplantation into the peripheral nerve graft had an inhibitory effect on diaphragm muscle atrophy. The SMNs transplanted into the peripheral nerve grafts formed a structure similar to the spinal cord, and the neuromuscular junction of the denervated diaphragm was reinnervated. These findings suggest the establishment of an ectopic motor neuron pool in the peripheral nerve graft. Free peripheral intra-nerve SMN transplantation in combination with NMES, which can be applied for diaphragmatic pacing, offers novel insights into the development of neuroregenerative therapies for treating life-threatening and intractable respiratory muscle paralysis caused by severe nerve damage and degenerative diseases.

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.

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.

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.

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.

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.

Diaphyseal forearm fracture management in adolescent patients from 2011 to 2020: A multicenter study of surgery and regional anesthesia trends.

BACKGROUND: Diaphyseal forearm fractures are common traumatic injuries among children. There has been much debate on the use of intramedullary nailing (IMN) or plate fixation in the adolescent population (10-16 years of age). Furthermore, as ultrasound technology has advanced, the safety and efficacy of ultrasound-guided axillary brachial plexus block for children has dramatically improved. Therefore, anesthesia options for adolescent patients have increased in recent years. This study aimed to investigate recent surgical and regional anesthesia trends of diaphyseal forearm fractures in patients 10 to 16 years of age in Japan through a multicenter epidemiological survey from 2011 to 2020. METHODS: This retrospective, multicenter study included 226 pediatric patients with diaphyseal forearm fracture aged 10-16 years treated from January 2011 to December 2020. We divided the patients into four groups according to the period in which they were treated: early (2011-2013), middle (2014-2016), late (2017-2019), and COVID-19 (2020). Information from medical records was used to investigate the number of surgeries, types of anesthesia administered, and internal fixation methods used for diaphyseal forearm fracture in adolescent patients during each period. RESULTS: The number of surgeries was generally constant in each period but decreased during the COVID-19 period. In the early, middle, late, and COVID-19 periods, the percentages of surgeries performed under regional anesthesia were 67.7, 85.5, 87.0, and 100% respectively (p = 0.003). During the same periods, the percentages of patients receiving IMN were 41.5, 49.3, 58.0, and 66.7%, respectively (p = 0.033). CONCLUSION: The use of IMN and regional anesthesia to treat diaphyseal forearm fracture in patients 10 to 16 years of age steadily increased during the study period from 2011 to 2020. These results indicate that regional anesthesia is safe, effective, and well-tolerated by adolescent patients. The treatment strategy for diaphyseal forearm fractures in adolescents using regional anesthesia in combination with IMN worked well and was effective during COVID-19. Our evidence suggests this trend will continue. We anticipate that our findings can be extrapolated for upper extremity fractures in adolescent patients beyond the Tokai region of Japan where the study was based.

Fracture of the patella involving inferior pole is associated with postoperative patella baja - A retrospective multicenter study.

BACKGROUND: The patella fracture involving of inferior pole fractures (IPF) may be associated with patella baja, However, the clinical impact of this condition remains unclear. This study aims to clarify 1) the incidence of patella baja following patellar fracture surgery, 2) the associated clinical outcomes with and without the presence of patella baja, and 3) the potential correlation between the detection of IPF on CT and the occurrence of patella baja. METHODS: We conducted a retrospective multicenter study involving 251 patients who underwent surgical treatment for patellar fractures. Patients were divided into the patella baja (PB; n = 49) group and patella norma (PN; n = 202) group. Data collected included demographics, radiographic findings, surgical details, and postoperative complications. We compared these items between PB group and PN group. Logistic regression analyses were used to identify risk factors for patella baja. RESULTS: Immediately following surgery, 36 (14.3%) patients presented with patella baja which increased to 49 cases (19.5%) at six months postoperatively. There is no statistically significant difference in the demographics, surgical details, clinical outcomes and complication between PB group and PN group. While, in the radiographical assessment, the prevalence of IPF on CT scan in the patella baja group was significantly higher than that in the patella norma group. By logistic regression analysis, IPFP on CT was identified as an independent risk factor for patella baja. (odds ratio 2.11, 95% confidence interval: 1.03-4.33, p = 0.042). CONCLUSION: In patients with patellar fractures, the incidence of patella baja increased from 14.3% immediately post-surgery to 19.5% at the six-month check-up. No significant differences were observed in clinical outcomes between the patella baja group and the norma group. The patella fracture involving IPF on CT emerged as a predictive factor for patella baja.

Does Preoperative Manual Reduction (Omoto Technique) Affect Surgical Outcomes for Calcaneal Fractures? A Multicenter (TRON Group) Retrospective Study.

The Omoto technique is a well-known method that is commonly used for noninvasive manual repair of calcaneal fractures. However, there have been no detailed studies on its clinical outcomes in preoperative closed reduction for surgical cases. This multicenter retrospective study aimed to compare the clinical and radiographic outcomes of calcaneal fractures treated with and without the preoperative Omoto technique, assessing its effectiveness. We extracted 335 patients with calcaneal fracture who underwent surgery between 2015 and 2020 from our multicenter database, named TRON. We evaluated the clinical outcomes using the American Orthopedic Foot and Ankle Society (AOFAS) score, the Böhler angle (BA) for radiographic analysis, and noted any complications. We divided the patients into those managed with the Omoto technique (group O) and those managed without the Omoto technique (group N). Patients were matched by age, sex, and fracture type, resulting in 43 patients per group. The use of the Omoto technique at the time of injury significantly improved the Böhler angle (BA). Furthermore, there were no significant differences in AOFAS, postoperative complications, or BA values at the final follow-up. In conclusion, our study demonstrates that the Omoto technique, when used preoperatively for calcaneal fractures, does not negatively impact the outcomes of subsequent surgical treatments. For patients who prefer to avoid surgery, the Omoto technique can be an effective initial intervention. Additionally, our findings suggest that the Omoto technique may facilitate less invasive surgical options in certain cases.

Does Early and Late Weight Bearing Have an Effect on the Results of Elderly Tibial Plateau Fractures with Internal Fixation?: A Multicenter (TRON Group) Study.

Introduction: There is still no consensus on the length of the non-bearing period required for tibial plateau fractures (TPFs) treated surgically. Several studies showed that full weight bearing immediately postoperatively does not affect fixation or cause joint collapse in patients with TPF. While there are concerns about weight bearing in the elderly due to fragile bone quality, their physical disability often makes it difficult to carry out activities of daily life when weight bearing is not allowed. The purpose of this study was to assess differences in clinical and radiographic outcomes between an early weight-bearing (EWB) group and a non-weight-bearing (NWB) group following TPF in elderly patients. Material and Methods: We extracted the data of 432 patients who suffered TPF from January 2011 to December 2020 from a database which is named TRON. We excluded patients with insufficient follow-up postoperatively, AO type A/C fracture, age < 60 years old, multiple trauma, and those lost to follow-up. Finally, 91 patients were eligible. EWB group patients were encouraged to perform partial weight-bearing walking at ≤ 4 weeks after surgery, whereas NWB group patients were not allowed weight bearing for > 4 weeks after surgery. Baseline intergroup differences were adjusted for by matching age, sex, body mass index, smoking history, and injury mechanism. We compared Knee Society Score (KSS), timing of full weight bearing, and X-ray findings including step-off, tibia plateau angle, plateau slope, and condylar widening in the X-rays between the two groups. Results: There were no significant statistical differences between the EWB group and NWB group after matching. The mean follow-up period was 28.0 (range 12-73) months. All cases did not require reoperation or additional procedures. The median KSS at 12 months or at the last follow up postoperatively was 100 (77-100) vs. 95 (75-100) points (P = 0.33). There were no differences in fracture-related infection rates or wound dehiscence. In the radiological evaluation of EWB and NWB, the correction loss of condylar widening was only significantly greater for EWB compared to NWB. Conclusions: We found that early weight bearing could contribute to increased condylar widening. While our short-term follow-up didn't reveal any significant clinical differences, this highlights the need for long-term follow-up to comprehensively understand the implications of these radiographic changes.

Comparing short vs. intermediate and long nails in elderly patients with unstable multifragmental femoral trochanteric fractures (AO type A2): Multicenter (TRON group) retrospective study.

BACKGROUND: Unstable femoral trochanteric fractures (FTFs), especially Arbeitsgemeinschaft für Osteosynthesefragen/ the Orthopedic Trauma Association (AO/OTA) 31-A2 fractures, which are multifragment fractures, occur in elderly individuals with osteoporosis and are associated with high mortality and complication rates due to prolonged immobilization. Longer nails (LNs) were developed to obtain superior fracture site stabilization in unstable FTFs. We hypothesized that the postoperative outcomes of elderly patients with unstable FTFs treated with LNs would be superior to those of patients treated with short nails (SNs), with fewer complications. METHODS: This multicenter retrospective study aimed to compare the outcomes of SNs versus LNs in elderly patients with unstable FTFs. From the Trauma Research Group of our university (TRON) database, 1854 trochanteric fractures treated between January 2016 and December 2020 were extracted. A total of 174 patients>65 years of age with AO/OTA 31-A2 fractures were included in the present study. They were divided into the SN group and the LN group and matched for age and sex. Parameters such as operative time, blood loss, survival rate, Parker Mobility Score (PMS), and numerical rating scale (NRS) for pain, complications, and radiographic findings were analyzed. RESULTS: Both groups included 67 patients with an average age of 87.32 years. The LN group had a longer operative time (76.52 min vs. 51.61 min, P < 0.001) and more blood loss (106.79 mL vs. 49.98 mL, P = 0.014) in comparison to the SN group. However, the 1-year survival rate, PMS, and NRS for pain did not differ to a statistically significant extent between the groups. The rates of complications, including screw cutout, nonunion, implant breakage, osteonecrosis of the femoral head, and surgical site infections, were comparable. The radiographic findings, including the nail/canal ratio, progression of varus, and sliding distance, were also similar. CONCLUSION: Although LNs are associated with longer operative times and increased blood loss, the overall outcomes and complication rates are comparable to those of SNs in elderly patients with AO/OTA 31-A2 type unstable FTFs. The use of LNs did not confer any distinct advantages for this specific type of fracture.

An age-matched comparative study on intramedullary nailing and plate fixation of both-bone diaphyseal forearm fracture in adolescents.

OBJECTIVE: This study aimed to compare radiological and functional outcomes and complication rates between intramedullary nailing (IMN) and plate fixation for diaphyseal forearm fractures in adolescents via an age-matched analysis. METHODS: Data were collected from medical records at 11 hospitals from 2009 to 2019, and the age-matched study was conducted between IMN and plate fixation. Functional outcomes, radiographic outcomes, and postoperative complication rates were compared. RESULTS: The IMN group (Group N) and plate fixation group (Group P) each comprised 26 patients after age matching. The mean age after matching was 13.42 years old. Bone maturities at the wrist of the radius and ulna were not significantly different between the two groups (p = 0.764 and p = 1). At the last follow-up period, functional outcomes using the Price criteria were over 90% in both groups, and the rotational range of motion was comparable to that of the healthy side. Over 70% of cases in Group N were performed by closed reduction, and operation time was half that of Group P. Postoperative neurological symptoms and refractures were more common in Group P than in Group N, although not statistically significantly so. CONCLUSIONS: Treatment outcomes for age-matched adolescent diaphyseal forearm fractures were excellent with IMN, as well as with plate fixation in many cases despite fewer complications, better cosmesis, and shorter operative times with IMN. IMN for diaphyseal forearm fractures is a useful treatment option even in adolescents although the indications for the best procedure to perform should be considered depending on individual patient needs. LEVEL OF EVIDENCE IV: Multicenter retrospective study.

Comparison of the Outcomes of Plating, Screw Fixation, and Pinning in Sanders Type II Fractures: A Multicenter (TRON) Retrospective Study.

Calcaneus fractures Sanders type II have been historically treated with various modalities. However, few studies compared these procedures directly. The multicenter (TRON group) retrospective study compared the radiographic and clinical outcomes of operative procedures using Kirschner wires (K-wires), cannulated cancellous screws (CCSs) and plates. Between 2014 and 2020, 121 patients with Sanders type II calcaneus fractures were surgically treated in our group using K-wire (Group K: n = 31), CCS (Group C: n = 60) or plate (Group p: n = 30) fixation. We assessed the American Orthopedic Foot and Ankle Society (AOFAS) score and infection after operation as clinical outcomes and Böhler's and Preiss' angles as radiographic outcomes. The AOFAS scores of the 3 groups showed a significant difference, with Group P showing significantly inferior scores to Group C at 6 months postoperatively and at the final follow-up examination (p = .015 and p < .001, respectively). The rate of infection did not differ to a statistically significant extent, but the incidence in Group P tended to be higher in comparison to the other groups. Among the three groups, Böhler's angle did not differ to a statistically significant extent immediately after the operation (p = .113) or at the final follow-up examination (p = .383). Postoperatively, Preiss' angle did not differ to a statistically significant extent (p = .251) but was significantly smaller in the Group C at the final follow-up examination (p = .0331). In Sanders type II calcaneus fracture, CCS fixation may obtain the best functional outcomes.

Predictive factors for one-year mortality after surgery for periprosthetic femoral fracture: A retrospective multicenter (TRON group) study.

BACKGROUND: Periprosthetic femoral fracture (PFF) after total hip arthroplasty (THA) or bipolar hip arthroplasty (BHA) represents a challenging situation and the treatment is associated with high rates of complications and mortality. The aims of this multicenter retrospective study were to determine 1-year mortality and to identify predictors associated with mortality, including patient characteristics and surgical factors, in patients undergoing surgery for PFF after THA or BHA. METHODS: We collected 249 cases of PPF after THA or BHA that were treated in our 11 hospitals (named the TRON group) between January 2010 and December 2019. We excluded patients who were conservatively treated, cases in which the 1-year postoperative outcome was unknown, and Vancouver type A cases. Finally, we analyzed 161 patients. Univariate and multivariate Cox regression analyses were performed to identify factors affecting 1-year mortality. Patient-side factors such as age, BMI, fracture type, and preoperative mobility, and surgical factors such as surgical procedure, time to surgery, and operation time were analyzed respectively. RESULTS: Eighteen of 161 patients (11.2%) died one year after surgery. The multivariate Cox regression analysis identified older age, wheelchair status before injury, and operation time as independent predictors of 1-year mortality (older age: hazard ratio [HR] 1.07, 95% CI 1.01-1.15, P = 0.048; wheelchair status: HR 5.82, 95% CI 1.01-33.47, P = 0.049; operation time: [HR] 1.01, 95% CI 1.00-1.01, P = 0.00929). Meanwhile, fracture type according to the Vancouver classification, body mass index, presence of previous fragility fractures, type of fixation, blood loss during operation, and time to surgery were not independent predictors of 1-year mortality in this analysis. ConclusionThe 1-year mortality rate after surgery for PPFs patients was 11.2%. Factors associated with older and poor activity of daily living (ADL) performance (e.g., wheelchair status before injury), and longer operative time were associated with 1-year mortality after surgery for PPF. Surgeons should carefully plan treatment according to each patient's condition.

Effect of anaesthesia on cemented hemiarthroplasty -A multicentre retrospective study (TRON study).

INTRODUCTION: This study aimed to investigate the survival rate, postoperative complications, and walking ability in cemented hemiarthroplasty (HA) for displaced femoral neck fractures according to the anaesthesia method. METHODS: We conducted a retrospective study of a multicentre group (the TRON group). Three hundred fifty-eight patients who underwent cemented HA between 2015 and 2019 were selected; 289 patients of ≥75 years of age with no missing data were included. Patient background factors were matched and patients were assigned to spinal anaesthesia (SA) and general anaesthesia (GA) groups. The primary outcome was death at any time during the follow-up period. Secondary outcomes included postoperative complications and walking ability assessed using the Parker mobility score (PMS). Overall survival was evaluated using the Kaplan-Meier method, and differences were compared using the log-rank test. The incidence of each complication and PMS were compared between the two groups using Fisher's exact test. RESULTS: Overall survival during follow-up was significantly higher in the SA group in comparison to the GA group (p = 0.037). In the SA and GA groups, the survival rate at 3 months postoperatively was 98.4% and 95.5%, respectively. The incidence of postoperative pneumonia was significantly higher in the GA (p = 0.012), and PMS at 3 months postoperatively was significantly higher in the SA group (p = 0.016). CONCLUSION: The survival rate of elderly patients who underwent cemented HA was better in the SA group. General anaesthesia in cemented HA may be associated with lower life expectancy, increased incidence of pneumonia, and decreased walking ability.

Early versus delayed weight bearing after internal fixation for femoral neck fracture in younger adults: A multicenter retrospective study.

INTRODUCTION: Femoral neck fracture (FNF) is among the most common and devastating injuries that orthopedic surgeons encounter. However, the incidence of FNF is lower in younger adults than in elderly individuals. In elderly FNF patients, early weight bearing (EWB) is preferred to prevent loss of function and decreased activity. In younger adults, some surgeons decide on delayed-weight bearing (DWB) after surgery because EWB may cause femoral neck shortening. We aimed to compare the postoperative results (clinical outcome, radiological evaluation, and complications) of EWB and DWB after FNF surgery in younger adults. METHODS: The study included 151 younger adults (age: ≤65 years at injury; nondisplaced, n = 100; displaced, n = 51) who underwent internal fixation at 11 university-affiliated hospitals in 2016-2020, and who were followed for ≥1 year. Patients were divided into the EWB (EWB in early postoperative period) and DWB (beginning weight bearing at 4 weeks after surgery) groups. The two groups were matched for age, and nondisplaced (EWB and DWB, both n = 24) and displaced (EWB and DWB, both n = 11) FNF were analyzed. The study items were age, sex, body mass index (BMI), Charlson Comorbidity Index (CCI), presence of diabetes, days waiting for surgery, fracture type, Parker mobility score (PMS) at last follow-up examination, pain (Numerical Rating Scale: NRS), radiological evaluation (femoral neck shortening, Canulated Cancellous screws (CCS) backout, and complications (nonunion, femoral head osteonecrosis). RESULTS: The patient backgrounds of the nondisplaced and displaced types did not differ. The PMS was significantly higher in the DWB group at the last follow-up examination (nondisplaced: 8.00±2.20 vs. 6.67±2.22, p = 0.005, displaced: 8.67±0.89 vs. 6.91±2.77, p<0.001). NRS and the amount of femoral neck shortening were significantly lower in the DWB group (nondisplaced: 1.65±0.70 mm vs. 3.94±3.03 mm, p<0.001, displaced: 4.26± 2.64 mm vs. 8.91±5.69 mm, p<0.001). CCS backout did not differ between the groups. One case of each of nonunion and femoral head osteonecrosis were observed in the displaced EWB and DWB groups; these differences were not significant. CONCLUSIONS: DWB after internal fixation for FNF in younger adults was associated with better outcomes than EWB.

Predictive factors for reoperation after periprosthetic femoral fracture: A retrospective multicenter (TRON) study.

BACKGROUND: The surgical treatment of periprosthetic femoral fracture (PFF) can be technically demanding and it is associated with high rates of complications and repeat surgery. However, repeat surgery is uncommon and few studies have examined survival and the functional prognosis following reoperation after the surgical treatment of PFF. We aimed to estimate the rate of reoperation for any reason, to determine the survival rate after reoperation for PFF, and to identify predictors associated with reoperation after PFF surgery in a multicenter (TRON group) study. METHODS: Two hundred forty-six patients were admitted for treatment of PFF. After excluding patients managed conservatively and those with Vancouver type A fracture, we analyzed 184 patients. Unadjusted risk ratios (RRs) were calculated, and multiple logistic regression was used to calculate adjusted RRs. We used the Kaplan-Meier method to create survival curves and a log-rank test to determine survival from the date of repeat surgery. RESULTS: Fifteen of the 184 patients (8.2 %) underwent reoperation after PFF surgery. The 1-year survival rate after reoperation for PFF was 66.7 % (11 of 15). Vancouver B3 and Vancouver C were identified as independent risk factors for reoperation after PFF surgery (Vancouver B3: Risk ratio [RR] 19.0, 95 % CI 1.10-329 P < 0.001; Vancouver C: RR 13.3, 95 % CI 1.4-123.0, P = 0.023). CONCLUSION: The reoperation rate after PFF surgery and the mortality after reoperation PFF surgery were relatively high. The fracture type is associated with reoperation after PFF surgery.

Locked Tension Band Wiring: A Modified Technique for Olecranon Fractures-A Multicenter Study Comparing Clinical Outcomes and Complications with Conventional Methods.

Purpose: Tension band wiring is the standard treatment for olecranon fractures, but it is associated with high rate of implant-related complication. To reduce this high complication rate, we developed a modified technique, locked tension band wiring (LTBW). The aim of this study was to investigate whether LTBW reduces complication and reoperation rates compared to conventional methods (CTBW). Methods: We identified 213 olecranon fractures treated with tension band wiring: 183 were treated with CTBW, and 30 were treated with LTBW, and patients in each group were selected using propensity score matching. We evaluated operation time, intraoperative bleeding, complication and reoperation rates, the amount of Kirschner's wire (K-wire) back-out, and Mayo Elbow Performance Index (MEPI). Complications included nonunion, loss of fracture reduction, implant failure, infection, neurological impairment, heterotopic ossification, and implant irritation. Implant removal included at the patient's request with no symptoms. Results: We finally investigated 29 patients in both groups. The mean operation time was significantly longer in the LTBW (106.7 ± 17.5 vs. 79.7 ± 21.1 min; p < 0.01). Complication rates were significantly lower in the LTBW than the CTBW group (10.3 vs. 37.9%; p = 0.03). The rate of implant irritation was more frequent in the CTBW, but there was no significant difference (3.4 vs. 20.7%; p = 0.10). Removal rate was significantly lower in the LTBW (41.4 vs. 72.4%; p = 0.03). The mean amount of K-wire backout at last follow-up was significantly less in the LTBW (3.79 ± 0.65 mm vs. 8.97 ± 3.54 mm; p < 0.01). There were no significant differences in mean MEPI at all follow-up periods (77.4 ± 9.0 vs. 71.5 ± 14.0; p = 0.07, 87.4 ± 7.2 vs. 85.2 ± 10.3; p = 0.40, 94.6 ± 5.8 vs. 90.4 ± 9.0; p = 0.06, respectively). Conclusion: Our modified TBW significantly increased operation time compared to conventional method, but reduced the complication and removal rate and had equivalent functional outcomes in this retrospective study.

Comparative Outcomes of Anterior and Posterior Plating for Distal-Third Humerus Shaft Fractures.

PURPOSE: When treating distal-third humerus shaft fractures (HSFs) surgically, the optimal approach for plating is controversial. We conducted a retrospective multicenter study to investigate and compare the clinical outcomes of anterior and posterior plating in distal-third HSFs and the incidence of complications including iatrogenic radial nerve palsy. METHODS: We identified 116 patients from our multicenter trauma database who were diagnosed as having distal-third HSFs and who underwent surgical treatment, including intramedullary nailing between 2011 and 2020. We analyzed 50 cases treated in one of two ways: open reduction internal fixation with anterior plating (group A: 20 cases) and open reduction internal fixation with posterior plating (group P: 30 cases). RESULTS: The findings were similar in terms of operation time, estimated bleeding, and clinical and radiographic outcomes between the groups. Postoperative radial nerve palsy occurred only in group P (4 cases) and never in group A. CONCLUSIONS: The results of this study suggest that the anterior approach is a safe and effective method for treating distal-third HSFs with satisfactory outcomes. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.