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.

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.

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.

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 non-invasive 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.

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.

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.

Early weight bearing versus late weight bearing after intramedullary nailing for distal femoral fracture (AO/OTA 33) in elderly patients: A multicenter propensity-matched study

BACKGROUND

This study aimed to assess differences in implant failure and bone union rates, amount of change in alignment of lower extremities, and walking ability between early weight-bearing (EWB) and late weight-bearing (LWB) groups following retrograde intramedullary nailing (RIMN) for distal femoral fracture (AO/OTA 33) (DFF) at multiple centers using propensity score matching.

METHODS

The data of 213 patients who underwent RIMN from 2012 to 2019 in multiple tertiary hospitals were extracted from our database. Cases with the following factors were excluded: age <60, open fracture, AO/OTA-type 33-C3 fracture, preoperative New Mobility Score (NMS) < 3, postoperative follow-up <3 months, and unknown weight-bearing start time. Eighty-four patients were divided into the EWB and LWB groups. EWB group patients were encouraged to perform partial weight-bearing walking at ≤4 weeks after surgery. LWB group patients were not allowed weight bearing for >4 weeks after surgery. After propensity score matching was applied, 26 cases remained in each group.

RESULTS

There were no cases of nail failure in either the EWB group or LWB group (P = 1). Screw failure occurred in 0 cases in the EWB group and in 1 case (4.5%) in the LWB group (P = 1.0). Non-union occurred in 5 patients (19.2%) in the EWB group and 4 patients (15.3%) in the LWB group (P = 1). The mean amount of change in lower extremities alignment did not differ between the two groups. The median Knee Society Score was 95.5 (59-100) vs. 93 (72-100) points (P = 0.39). The median NMS was 7 (0-9) vs. 7 (4-9) points (P = 0.82).

CONCLUSIONS

There were no significant intergroup differences in the rates of implant failure, bone union at one year after surgery, amount of change in lower extremities alignment, or walking ability. We suggest that early weight bearing after RIMN for DFF may not be harmful in elderly people.

Home exercises after volar locking plate fixation for distal radius fracture in the elderly are as effective as supervised physiotherapy -multicenter retrospective study

BACKGROUND

Although home exercises are used for postoperative rehabilitation of distal radius fractures (DRF), the superiority of home exercise over supervised physiotherapy rehabilitation is controversial. This study aimed to compare the function of home exercise and supervised physiotherapy rehabilitation during postoperative rehabilitation for DRF.

METHODS

We conducted a multicenter, retrospective study in which we included 1949 patients over 65 years old who underwent volar locking plate fixation for DRF. After propensity score matching, 308 patients were assigned to each of an independent home exercise group (IHG) and supervised physiotherapy group (SPG). Wrist function was assessed after 3, 6, and 12 months postoperatively.

RESULTS

The results showed that the Mayo Wrist Score did not differ significantly within the observation period. Range of motion of the wrist was better in the SPG up to 3 months postoperatively but was almost the same as that in the IHG at 6 months. However, the Numerical Rating Scale score was lower in the IHG during all observation periods.

CONCLUSIONS

Home exercise may be as effective as supervised physiotherapy in the medium term, but supervised physiotherapy rehabilitation should be considered if early recovery and good wrist function are desired.

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.

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.

What factors are associated with loss of alignment after open reduction and internal fixation for tibial plateau fractures? A retrospective multicenter (TRON group) study

BACKGROUND

Tibial plateau fractures (TPFs) are one of the most challenging intra-articular fractures to treat. Along with reconstruction of the articular surfaces, appropriate alignment of the knee joints must be obtained and maintained after open reduction and internal fixation (ORIF) for TPFs because loss of alignment (LA) is associated with worse clinical outcomes. We aimed to investigate and clarify the risk factors related to LA after ORIF for TPFs.

METHODS

This multicenter, retrospective cohort study used data of hospitals of the Trauma Research Group (TRON group) from January 1, 2011, to December 31, 2020. Among 293 TPFs extracted from the database, we evaluated the alignment of the articular surface to the anatomical axis of the tibia in the immediate postoperative and last follow-up radiographs. We defined a change of alignment from the immediate postoperative radiograph as LA. We evaluated the risk factors of LA using univariate and multiple logistic regression analyses.

RESULTS

LA was observed in 27 fractures (9.2%). In multiple logistic regression analyses, preoperative articular step-off and postoperative condylar widening were statistically associated with LA (OR = 1.1, 95% CI: 1.02-1.19 and P = 0.012; OR = 1.04, 95% CI: 1.00-1.08, P = 0.045, respectively). We calculated the threshold by drawing a receiver operating characteristic curve using the final regression model. The threshold of postoperative widening was 8.2 mm. We divided the 293 TPFs into two groups according to this threshold and determined differences between the two groups using Fisher's exact test. The two groups were statistically significantly different (P = 0.00502).

CONCLUSIONS

Preoperative articular step-off and postoperative condylar widening could be associated with LA after ORIF for TPFs. We suggest that intraoperative restoration of condylar widening is important for the prevention of malalignment following ORIF for TPF.

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.

Ulnar Nerve Neuropathy After Surgery for Intraarticular Distal Humerus Fractures: An Analysis of 116 Patients

PURPOSE

To identify the incidence and the factors associated with a postoperative ulnar nerve neuropathy in patients who had undergone open reduction and internal fixation for intraarticular distal humerus fractures.

METHODS

We retrospectively reviewed 116 patients who had undergone surgery between January 2011 and December 2020. Age, sex, BMI, mechanism of injury, open or closed fracture, operation time, tourniquet time, and nerve injury at the final examination were collected from medical charts. We essentially used the paratricipital approach. In cases in which the reduction of intraarticular bone fragments was difficult, olecranon osteotomy was used. Ulnar nerve function was graded according to a modified system of McGowan. We conducted logistic regression analysis to investigate factors of neuropathy using items identified as statistically significant in univariate analysis as explanatory variables.

RESULTS

Thirty-four patients (29.3%) had persistent neuropathy at the final follow-up. In the modified McGowan classification, 28 patients had grade 1 and 6 patients had grade 2 neuropathy. Olecranon osteotomy emerged as a distinct explanatory variable for the prophylaxis of ulnar nerve neuropathy in the multivariate analysis (odds ratio, 0.30; 95% confidence interval, 0.12-0.73). Anterior transposition, however, was not a statistically significant factor (odds ratio, 1.91; 95% confidence interval, 0.81-4.56).

CONCLUSIONS

Olecranon osteotomy was the only independent factor associated with preventing the occurrence of ulnar nerve neuropathy. Ulnar nerve transposition might not be associated with prevention of ulnar nerve neuropathy.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic IV.

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.

What is the Radiographic Factor Associated with Meniscus Injury in Tibial Plateau Factures? Multicenter Retrospective (TRON) Study

Purpose

Tibial plateau fracture (TPF) is a complex intra-articular injury involving comminution and depression of the joint, which can be accompanied by meniscal tears. The aims of this study were (1) to demonstrate the rate at which surgical treatment for lateral meniscal injury and (2) to clarify the explanatory radiographic factors associated with meniscal injury in patients with TPF.

Methods

We extracted the patients who received surgical treatment for TPF from our multicenter database (named TRON) included from 2011 to 2020. We analyzed 79 patients who were received surgical treatment for TPF with Schatzker type II and III and evaluation for meniscal injury on arthroscopy. We investigated the rate at which surgical treatment of the lateral meniscus was required in patients with TPF and the explanatory radiographic factors associated with meniscal injury. Radiographs and CT scans were evaluated to measure the following parameters: tibial plateau slope, distance from lateral edge of the articular surface to fracture line (DLE), articular step, and width of articular bone fragment (WDT). Meniscus tears were classified according to whether surgery was necessary. The results were analyzed by multivariate Logistic analyses.

Results

We showed that 27.7% (22/79) of cases of TPF with Schatzker type II and III had lateral meniscal injury that required repair. WDT ≥ 10 mm (odds ratio 10.9; p = 0.005) and DLE ≥ 5 mm (odds ratio 5.7; p = 0.05) were independent explanatory factors for meniscal injury with TPF.

Conclusion

Bone fragment size and the location of fracture line on radiographs in patients with TPF are associated with meniscus injuries requiring surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-023-00888-5.

Predictors of postoperative complications of tension band wiring techniques for patella fracture: A retrospective multicenter (TRON group) study

OBJECTIVE

The relationship between postoperative complications and operative techniques of tension band wiring (TBW) is not well studied. We aimed to evaluate the incidence of implant breakage, implant migration, and loss of reduction in patellar fractures treated with TBW and identify radiographic factors associated with these postoperative complications.

METHODS

This multicenter (named, TRON group) retrospective study included 224 patients who underwent open reduction and internal fixation of patella fractures using TBW from January 2016 to December 2020. Radiographic findings were evaluated by experienced orthopedic surgeons, and radiographic outcomes were assessed for K-wire migration, implant breakage, and loss of reduction. Logistic regression analysis was performed to identify radiographic factors associated with postoperative complications.

RESULTS

Implant migration occurred in 44 cases (19.6%), with bending of a single K-wire end identified as a significant risk factor (OR: 12.90; 95% CI: 4.99-33.30; P < 0.001). Implant breakage occurred in 43 cases (19.2%), with a large patella-tension band ratio (OR: 291.0; 95% CI: 19.60-4330; P < 0.001) and a wide distance between K-wires (OR: 1.15; 95% CI: 1.060-1.250; P = 0.001) identified as significant risk factors. Loss of reduction occurred in 5 cases (2.0%), but no significant risk factors were identified.

CONCLUSION

This study highlights the importance of bending both ends of the K-wires and proper placement of the tension band and K-wires in reducing postoperative complications in patellar fractures treated with TBW. Further research is needed to better understand the risk factors associated with loss of reduction.

Retrospective multicenter (TRON group) study of humeral shaft fragility fractures: Analysis of mortality rates and risk factors

AIMS

This study aimed to show the mortality rate following humeral shaft fragility fractures (HSFF) in the elderly. The secondary aim was to examine the predictors associated with mortality in elderly patients who have sustained HSFF.

METHODS

From 2011 to 2020, all elderly patients aged 65 years and older with HSFF managed at our nine hospitals were retrospectively identified from our TRON database. Patient demographics and surgical characteristics were extracted from medical records and radiographs, and multivariable Cox regression analysis was used to identify factors affecting mortality.

RESULTS

In total, 153 patients who sustained HSFF were included. The mortality rate for HSFF in the elderly was 15.7% at 1 year and 24.6% at 2 years. Multivariable Cox regression analysis showed significant differences in survival for the following variables: older age (p < 0.001), underweight (p = 0.022), severely ill (p = 0.025), mobility limited to indoors (p = 0.003), dominant-side injury (p = 0.027), and nonoperative treatment (p = 0.013).

CONCLUSION

The outcome following HSFF in the elderly population appears to be relatively grim. The prognosis of elderly patients with HSFF is closely related to their medical history. In the elderly patients with HSFF, operative treatment should be positively considered while taking into account their medical status.

Comparison of surgical treatments for distal ulna fracture when combined with anterior locking plate fixation of distal radius in the over 70 age group

We conducted a retrospective multicentre study to compare the clinical and radiographic outcomes, and complications of three surgical treatments of distal ulna fracture (DUF) when combined with anterior locking plate fixation for distal radial fracture (DRF) in patients over 70 years of age. We identified 1521 patients over 70 years of age who were diagnosed as having DRF and who underwent anterior locking plate fixation between 2015 and 2020, among which 122 cases of DUF were analysed. Three surgical treatment options for DUF were identified in this cohort: K-wire fixation (Group K), locking plate fixation (Group L) and Darrach procedure (Group D). The results of the analysis showed the total immobilization period in Group D to be the shortest among the three treatments. Functional outcomes were superior, and the rate of complications were smaller in Group D than in Group L. In addition, rotational range of motion was larger in Group D and Group L compared with Group K. In patients who are 70 years of age or older with combined unstable DRF and highly comminuted or displaced DUF, the Darrach procedure for DUF seems to be the most useful and reasonable treatment option once the fracture of the distal radius has been rigidly fixed.Level of evidence: IV.

Incidence and Risk Factors for Fracture-Related Infection After Peri-Prosthetic Femoral Fractures: A Multicenter Retrospective Study (TRON Group Study)

Background: Fracture-related infection (FRI) sometimes occurs with peri-prosthetic femoral fracture (PPF) treatment. Fracture-related infection often leads to multiple re-operations, possible non-union, a decreased clinical function, and long-term antibiotic treatment. In this multicenter study, we aimed to clarify the incidence of FRI, the causative organisms of wound infection, and the risk factors associated with post-operative infection for PPF. Patients and Methods: Among 197 patients diagnosed with peri-prosthetic femoral fracture who received surgical treatment in 11 institutions (named the TRON group) from 2010 to 2019, 163 patients were included as subjects. Thirty-four patients were excluded because of insufficient follow-up (less than six months) or data loss. We extracted the following risk factors for FRI: gender, body mass index, smoking history, diabetes mellitus, chronic hepatitis, rheumatoid arthritis, dialysis, history of osteoporosis treatment, injury mechanism (high- or low-energy), Vancouver type, and operative information (waiting period for surgery, operation time, amount of blood loss, and surgical procedure). We conducted a logistic regression analysis to investigate the risk factors for FRI using these extracted items as explanatory variables and the presence or absence of FRI as the response variable. Results: Fracture-related infection occurred after surgery for PPF in 12 of 163 patients (7.3%). The most common causative organism was Staphylococcus aureus (n = 7). The univariable analysis showed differences for dialysis (p = 0.001), Vancouver type (p = 0.036), blood loss during surgery (p = 0.001), and operative time (p = 0.001). The multivariable logistic-regression analysis revealed that the patient background factor of dialysis (odds ratio [OR], 22.9; p = 0.0005), and the operative factor of Vancouver type A fracture (OR, 0.039-1.18; p = 0.018-0.19) were risk factors for FRI. Conclusions: The rate of post-operative wound infection in patients with a PPF was 7.3%. Staphylococcus was the most frequent causative organism. The surgeon should pay attention to infection after surgery for patients with Vancouver type A fractures and those undergoing dialysis.

＜Editors' Choice＞ Hook plate fixation versus locking plate fixation for distal clavicle fracture: a multicenter propensity score-matched study

Hook plate fixation and locking plate fixation are two standard internal fixation implants for treating distal clavicle fractures. We aimed to clarify the following: 1) Does the locking plate offer better clinical outcomes than the hook plate? 2) Is bone union better with a locking plate than hook plate? and 3) Are complications different between the locking plate and hook plate? We conducted a retrospective multicenter study of 338 patients who underwent surgery from 2014 to 2018 in our 10 hospitals, which comprise the TRON group. Of them, 208 patients treated using any plates were eligible. After 30 patients were excluded for various reasons, 178 patients were included. We classified them into two groups, locking plate group (Group L) and hook plate group (Group H), using propensity score matching. We confirmed bone union with an X-ray, evaluated the UCLA shoulder score, and compared the frequency of complications. After matching, Group L and Group H included 49 patients each. The UCLA score was higher in Group L than in Group H at each follow-up point. We confirmed bone union in all patients in Group L, but it was not confirmed in three patients (6.1%) in Group H. No statistically significant differences were observed except for plate migration, which was observed in nine patients (18.4%) in Group H but in no patients in Group L. The postoperative UCLA score was significantly better in Group L. We recommend the locking plate as a surgical treatment for distal clavicle fractures.

Locked Tension Band Wiring for Mayo IIA Olecranon Fractures: Modified Surgical Technique and Retrospective Comparative Study of Clinical Outcomes and Cost-effectiveness with Locking Plate

Background: Tension band wiring (TBW) has traditionally been used for simple olecranon fractures, but due to its many complications, locking plate (LP) is increasingly being employed. To reduce the complications, we developed a modified technique for olecranon fracture repair, locked TBW (LTBW). The study aimed to compare (1) the frequency of complications and re-operations between LP and LTBW techniques, (2) clinical outcomes and the cost efficacy. Methods: We retrospectively evaluated data of 336 patients who underwent surgical treatment for simple and displaced olecranon fractures (Mayo Type ⅡA) in the hospitals of a trauma research group. We excluded open fractures and polytrauma. We investigated complication and re-operation rates as primary outcomes. As secondary outcomes, Mayo Elbow Performance Index (MEPI) and the total cost, including surgery, outpatients and re-operation, were examined between the two groups. Results: We identified 34 patients in the LP group and 29 patients in the LTBW group. The mean follow-up period was 14.2 ± 3.9 months. The complication rate in the LTBW group was comparable to that in the LP group (10.3% vs. 17.6%; p = 0.49). Re-operation and removal rates were not significantly different between the groups (6.9% vs. 8.8%; p = 1.000 and 41.4% vs. 58.8%; p = 1.00, respectively). Mean MEPI at 3 months was significantly lower in the LTBW group (69.7 vs. 82.6; p < 0.01), but mean MEPI at 6 and 12 months were not significantly different (90.6 vs. 85.2; p = 0.06, 93.9 vs. 95.2; p = 0.51, respectively). The mean cost/patient of the total cost in the LTBW group were significantly lower than those in the LP group ($5,249 vs. $6,138; p < 0.001). Conclusions: This study showed that LTBW achieved clinical outcomes equivalent to those of LP and was significantly more cost effective than LP in the retrospective cohort. Level of Evidence: Level III (Therapeutic).

Longer time of implantation using the buried pin technique for intramedullary nailing would decrease refracture in the diaphyseal forearm fracture in children-retrospective multicenter (TRON) study

BACKGROUND

Intramedullary nailing using Kirschner wires in pediatric diaphyseal forearm fractures is often performed as a less invasive treatment than plate fixation, but it remains controversial whether the tips of Kirschner wires are buried or exposed. The purpose of this study was to investigate the relationship between whether the tips are buried or exposed and complications, especially of refracture.

METHODS

Data of 405 patients under 16 years who underwent surgical treatment for diaphyseal forearm fractures in our 11 hospitals between 2010 and 2020 were collected. Finally, 143 patients who underwent intramedullary nailing with at least 6-month follow-up were analyzed. We investigated difference in complication rates depending on whether the Kirschner wire tips were buried (Group B: n = 79) or exposed (Group E: n = 64). Regarding refractures, we also examined time of onset and status of bone union before the refracture occurred.

RESULTS

The duration before implant removal in Group B was more than 4 times longer than that in Group E (mean 187.9 vs. 41.4 days, p<0.001), although there was no significant difference in the progression of bone union between the two groups. Regarding postoperative complications, Group B had a significantly lower rate of refractures than Group E (7.9% vs. 32.8%, p<0.001), although the rate of irritation pain was significantly higher (15.2% vs. 1.6%, p = 0.006). The infection rate was also lower in Group B than Group E, but not significantly so (3.8% vs. 10.9%, p = 0.112). Refractures between 3 and 9 months after surgery accounted for 66.7% of all refractures, and those within 3 months accounted for 14.5% of all fractures. There was no significant difference in the status of bone union before the refracture occurred between patients with and without refracture.

CONCLUSIONS

The present study showed that longer time of implantation using the buried pin technique for intramedullary nailing reduces refracture of pediatric diaphyseal forearm fractures. Because of the risk of refracture during remodeling, we recommend the implantation of intramedullary nailing for 6-9 months and the instruction for the patients and the parents to pay more attention to refracture at least within 9 months postoperatively.

LEVEL OF EVIDENCE

Level Ⅲ, Multicenter retrospective study.

Retrospective Comparative Study of Clinical Outcomes and Cost-Effectiveness with Bone Substitutes on Volar Locking Plate Fixation of Unstable Distal Radial Fractures in the Elderly

Background: This multicenter retrospective study aimed to compare clinical outcomes and cost-effectiveness with bone substitutes on volar locking plate (VLP) fixation of unstable distal radial fractures (DRF) in the elderly. Methods: The data of 1,980 patients of ≥65 years of age who underwent surgery for the DRF with a VLP in 2015-2019 were extracted from a database (named TRON). Patients lost to follow-up or who received autologous bone grafting were excluded. The patients (n = 1,735) were divided into the VLP fixation alone (Group VLA) and VLP fixation with bone substitutes (Group VLS). Propensity score matching of background characteristics (ratio, 4:1) was performed. The modified Mayo wrist scores (MMWS) were evaluated as clinical outcomes. The implant failure rate, bone union rate, volar tilt (VT), radial inclination (RI), ulnar variance (UV) and distal dorsal cortical distance (DDD) were evaluated as radiologic parameters. We also compared the initial surgery cost and total cost for each group. Results: After matching, the backgrounds of Groups VLA (n = 388) and VLS (n = 97) were not significantly different. The MMWS values of the groups were not significantly different. Radiographic evaluation revealed no implant failure in either group. Bone union was confirmed in all patients in both groups. The VT, RI, UV and DDD values of the groups were not significantly different. The initial surgery cost and total cost in the VLS group were significantly higher than those in the VLA group ($3,515 vs. $3,068, p < 0.001). Conclusions: In patients of ≥65 years of age with DRF, the clinical and radiological outcomes of VLP fixation with bone substitutes did not differ from those of VLP fixation alone, yet the additional use of bone augmentation was associated with higher medical costs. The indications for bone substitutes should be more strictly considered in the elderly with DRF. Level of Evidence: Level IV (Therapeutic).

Mortality and clinical outcomes of Vancouver type B periprosthetic femoral fractures : a multicentre retrospective study

AIMS

The objectives of this study were to investigate the patient characteristics and mortality of Vancouver type B periprosthetic femoral fractures (PFF) subgroups divided into two groups according to femoral component stability and to compare postoperative clinical outcomes according to treatment in Vancouver type B2 and B3 fractures.

METHODS

A total of 126 Vancouver type B fractures were analyzed from 2010 to 2019 in 11 associated centres' database (named TRON). We divided the patients into two Vancouver type B subtypes according to implant stability. Patient demographics and functional scores were assessed in the Vancouver type B subtypes. We estimated the mortality according to various patient characteristics and clinical outcomes between the open reduction internal fixation (ORIF) and revision arthroplasty (revision) groups in patients with unstable subtype.

RESULTS

The one-year mortality rate of the stable and unstable subtype of Vancouver type B was 9.4% and 16.4%. Patient demographic factors, including residential status and pre-injury mobility were associated with mortality. There was no significant difference in mortality between patients treated with ORIF and Revision in either Vancouver B subtype. Patients treated with revision had significantly higher Parker Mobility Score (PMS) values (5.48 vs 3.43; p = 0.00461) and a significantly lower visual analogue scale (VAS) values (1.06 vs 1.94; p = 0.0399) for pain than ORIF in the unstable subtype.

CONCLUSION

Among patients with Vancouver type B fractures, frail patients, such as those with worse scores for residential status and pre-injury mobility, had a high mortality rate. There was no significant difference in mortality between patients treated with ORIF and those treated with revision. However, in the unstable subtype, the PMS and VAS values at the final follow-up examination were significantly better in patients who received revision. Based on postoperative activities of daily life, we therefore recommend evision in instances when either treatment option is feasible.Cite this article: Bone Jt Open 2023;4(1):38-46.

Are the Clinical Results of Locking Plate Fixation for Distal Radius Fractures Inferior in Patients over 80 Years of Age? A Multicentre (TRON Group) Study

Introduction

With the aging of the population, the proportion of distal radius fracture patients who are > 80 years of age is increasing. In this study, we compared the postoperative clinical and radiographic outcomes between super-elderly patients (age: ≥ 80 years) and middle-elderly (age: 65-79 years) who were treated with volar locking plate (VLP) fixation for distal radius fractures.

Patients and Methods

Patients of > 65 years of age with distal radius fractures treated by VLP fixation between 2015 and 2019, and who were followed for at least 6 months after surgery were included in our database (named TRON). Patients with open fractures, multiple-trauma, or who received fixation with implants other than a VLP were excluded. We evaluated postoperative complications, Mayo wrist score (MWS), and radiographic outcomes.

Results

We identified 589 patients in this study; 452 were 65-79 years of age (Group A) and 137 were ≥ 80 years of age (Group B). After propensity score matching, we evaluated 309 patients in Group A and 103 patients in Group B. The mean follow-up period was 10.7 ± 4.6 months. Twenty-eight patients (9.1%) in Group A and 5 patients in Group B (4.9%) experienced post-operative complications (non-significant: p = 0.212). The postoperative MWS at 1, 3, and 6 months, respectively, was 65.4 ± 11.7, 75.2 ± 11.0, and 79.6 ± 10.5 in Group A and 67.1 ± 9.61, 75.7 ± 10.7, and 80.6 ± 9.7 in Group B (non-significant: p = 0.418, 0.893, 0.452, respectively). The differences in volar tilt, radial inclination, ulnar variance between the postoperative and last follow-up radiographs did not differ between the two groups to a statistically significant extent (p = 0.053, 0.437, 0.529, respectively).

Conclusion

Our study showed that the clinical and radiographic outcomes of distal radius fractures treated with VLP in super-elderly patients were comparable to those in middle-elderly patients.

A less invasive operative method using a medial cannulated cancellous screw and single plate fixation for the treatment of transcondylar fracture of the humerus in elderly patients in multicenter (TRON group) study

BACKGROUND

Double plate fixation for transcondylar fracture (TCF) tends to be more invasive to the soft tissue, and often carries a higher risk of postoperative complications, including ulnar nerve neuropathy. This study presents the outcomes of TCF of the distal humerus between patients treated with a single plate and cannulated cancellous screw fixation and patients treated with double plate fixation.

METHODS

Between 2011 and 2021, 371 cases involving treatment of distal humeral fracture were recorded in our multicenter (named TRON group) database. Patients of ≥ 65 years of age with TCF treated with opeb n reduction and internal fixation were included. Clinical outcomes were assessed by the Mayo elbow performance score, range of motion, and total elbow arc joint. Complications included fracture-related infection (FRI) and ulnar neuropathy.

RESULTS

There were significant differences in the average operative time (CCS group vs. Plate group: 119.0 min vs. 186.5 min; p < 0.001) and average tourniquet time (CCS group vs. Plate group: 91.5 min vs. 121.0 min; p < 0.001). FRI occurred as a complication in the Plate group (n = 6). The rates of FRI did not differ to a statistically significant extent (CCS group vs. Plate group: 0% vs. 9.2%; p = 0.477). No patients underwent reoperation. The rate of sensory symptoms in the Plate group was higher than that in the CCS group (CCS group: none [n = 25], numbness [n = 1] vs. Plate group: none [n = 57], numbness [n = 15], sensory depression [n = 2]; p = 0.039).

DISCUSSION

Among patients of ≥ 65 years of age with TCF, the clinical outcomes of patients treated with medial CCS and lateral/posterolateral plate did not differ from those of patients who received double plate fixation, and the former treatment was associated with significantly fewer complications, including ulnar nerve palsy. In addition to double plate fixation, this less invasive method of medial CCS and single plate fixation should be considered as a treatment option for TCF in elderly patients.

Clinical comparison of double-plate fixation by the perpendicular plate method versus parallel plate method for distal humeral fracture: a multicenter (TRON group) study

INTRODUCTION

Double-plating methods are popular, with perpendicular and parallel plate methods being widely used surgical method for the rigid fixation of distal humeral fracture (DHF). However, which plate method is better for DHF remains controversial. The aim of this study was to compare patient outcomes including the incidences of complications and reoperation between the two plate methods.

METHODS

We extracted 383 patients with DHF undergoing surgery between 2011 and 2020 from our multicenter database, which is named TRON. We divided the subjects into two groups: perpendicular plating group (Group A) and parallel plating group (Group B). To adjust for baseline differences between the groups, patients were matched for age, sex, olecranon osteotomy, AO type, and type of injury. We assessed the Mayo Elbow Performance Score (MEPS) at 3 and 6 months and the last follow-up month as the clinical outcome. We investigated the incidences of complications and reoperations in both groups.

RESULTS

After matching, each group comprised 50 patients. There was no significant difference between Group A versus Group B in MEPS score at each time point. The incidence of implant removal in Group B was higher than that in Group A (26.5% vs 50%, p = 0.023).

DISCUSSION

Although there were no significant differences in clinical outcomes or complications between the two groups, the incidence of implant removal was higher in Group B than in Group A. In the parallel plate technique, where the plates have to be placed in areas with thin subcutaneous soft tissue, the incidence of implant removal might be high due to the discomfort caused by the implant.

Do heel-unloading orthoses improve clinical outcomes in patients after surgical treatment of calcaneal fracture? A propensity-matched, multicenter analysis of the TRON database

BACKGROUND

Postoperative protocols after surgical treatment of calcaneal fracture have not been standardized to date. There are only a few reports on the efficacy of heel-unloading orthoses (HUOs; Mars shoe, Graffin orthosis), and thier efficacy is uncertain.

OBJECTIVES

The purpose of this study was to compare postoperative radiologic and clinical outcomes in patients with calcaneal fractures who used Graffin orthosis.

STUDY DESIGN

Multicenter retrospective study.

METHODS

We finally extracted 182 patients from a database of the Trauma Research Group of Nagoya and divided them into two groups: group C (underwent casting or splinting only) and group O (Graffin orthosis was used). A propensity score algorithm was used to match group C to group O in a 1:1 ratio. We evaluated American Orthopaedic Foot and Ankle Society (AOFAS) score at three and six months after surgery and at final follow-up. Differences in reduction of the Böhler angle between the two groups were evaluated radiographically. All data were analyzed with a t-test or Fisher's exact test. P < .05 was considered statistically significant.

RESULTS

The AOFAS score 3 months after surgery in group O was significantly higher than that in group C (69.57 vs. 77.22; P = .004). However, there were no statistically significant differences between group C vs. group O in AOFAS scores at 6 months after surgery and at final follow-up (81.92 vs. 85.67 and 89.18 vs. 88.13; P = .087 and 0.597, respectively). There was no significant statistical difference in the reduction of the Böhler angle (5.07 vs. 5.89; P = .529).

CONCLUSIONS

At 3 months postoperatively, the orthosis group showed predominantly better functional results. We believe that heel-unloading orthoses are useful for patients who require an early return to work and to daily life.

A Wirelessly Powered 4-Channel Neurostimulator for Reconstructing Walking Trajectory

A wirelessly powered four-channel neurostimulator was developed for applying selective Functional Electrical Stimulation (FES) to four peripheral nerves to control the ankle and knee joints of a rat. The power of the neurostimulator was wirelessly supplied from a transmitter device, and the four nerves were connected to the receiver device, which controlled the ankle and knee joints in the rat. The receiver device had functions to detect the frequency of the transmitter signal from the transmitter coil. The stimulation site of the nerves was selected according to the frequency of the transmitter signal. The rat toe position was controlled by changing the angles of the ankle and knee joints. The joint angles were controlled by the stimulation current applied to each nerve independently. The stimulation currents were adjusted by the Proportional Integral Differential (PID) and feed-forward control method through a visual feedback control system, and the walking trajectory of a rat's hind leg was reconstructed. This study contributes to controlling the multiple joints of a leg and reconstructing functional motions such as walking using the robotic control technology.

Comparison of functional outcome and complications of locking plate versus coracoclavicular fixation in the treatment of unstable distal clavicle fractures: the multicenter, propensity-matched TRON study

PURPOSE

This multicenter, retrospective study aimed to compare clinical outcomes and complications between locking plate fixation and new coracoclavicular (CC) fixation for patients with unstable distal clavicle fracture.

METHODS

We included 142 patients in this TRON study. The mean follow-up was 15.5 (6-31) months. The patients were divided into two groups: the locking plate group (Group L) and CC fixation group (Group C). To adjust for baseline differences between the groups, a propensity score algorithm was used to match two groups in a 1:1 ratio. After matching, we compared operation time and the University of California Los Angeles (UCLA) shoulder score at 3 and 6 months postoperatively and at last follow-up as clinical outcomes and the rate of complications.

RESULTS

After matching, 20 cases from each group remained. Operation time was shorter in Group C (75 [22, 111] vs. 100 [38, 120] min; P = 0.023). At 3 months postoperatively, UCLA score in Group C was better, but no significant differences between the groups were found at 6 months and last follow-up after surgery. The rate of complications was not significantly different between the groups.

CONCLUSION

CC fixation might be equivalent to locking plate fixation in clinical outcome, and the operation time is shorter than that required for locking plate fixation.

Mortality and functional outcomes of fragility fractures of the pelvis by fracture type with conservative treatment: a retrospective, multicenter TRON study

PURPOSE

Fragility fractures of the pelvis (FFP) are becoming a commonly encountered disease in aging societies. We aimed to (1) clarify the overall survival rate of FFP, (2) compare survival rates by Rommens and Hofmann classification FFP type, (3) investigate the complications during hospitalization, and (4) investigate walking ability before and after injury depending on the type of fracture in patients with FFP treated conservatively.

METHODS

This retrospective, multicenter study included 867 patients with FFP treated conservatively between 2014 and 2018 and excluded patients with insufficient follow-up for two years, lost data, and operative cases. This is a retrospective multicenter study. We established the database, which is named as TRON. We evaluated survival rate by fracture type using the log-rank test. We compared walking ability as defined by a new mobility score and the modified Majeed Pelvic Score among fracture types.

RESULTS

We reviewed 552 cases (98 males and 454 females) with conservative treatment. The overall survival rates of patients with FFP treated conservatively were 0.90 at 1 year and 0.83 at 2 years. Although the survival rate was the lowest in FFP Type III, there was no significant difference in survival rates between fracture types (P = 0.143). The rates of complications during hospitalization were high for both Type III and Type IV fractures. Walking ability post-injury was worse in the patients with Type III fracture.

CONCLUSIONS

The survival rate of patients treated by conservative treatment was relatively good. Type III in the Rommens and Hofmann classification was related to lower life expectancy and loss of walking ability.

Risk factors for fracture-related infection after open reduction and internal fixation of proximal humerus fractures: A multicenter retrospective study of 496 fractures (TRON group study)

INTRODUCTION

One of the complications of the surgical therapy for proximal humerus fractures is fracture-related infection (FRI). This multicenter study aimed to investigate the incidence of FRI and clarify the risk factors associated with FRI in patients receiving open reduction and internal fixation for proximal humerus fracture.

MATERIAL AND METHODS

Among 684 patients diagnosed as having proximal humerus fracture and who were treated by surgical therapy in 13 institutions (named TRON group) from 2015 through 2020, 496 patients (men, n = 134, women, n = 362; mean [SD] age, 68.5 [14.5] years; mean [SD] body mass index [BMI], 23.0 [4.4] kg/m²) were included as subjects. Excluded were 188 patients due to less than 12 month's follow-up, patients who underwent osteosynthesis using neither plate nor nail and those with open fracture. We extracted the following as risk factors of FRI: sex, BMI, smoking status, diabetes, glenohumeral fracture dislocation, fracture classification, approach, implant, waiting period, type of anesthesia, operative time and blood loss during surgery. We conducted logistic regression analysis to investigate the risk factors of FRI using these extracted items as explanatory variables and the presence or absence of FRI as the response variable.

RESULT

FRI occurred after surgery for proximal humerus fracture in 9 of the 496 patients (1.8%). The causative organism was methicillin-susceptible Staphylococcus aureus in 4 patients, Pseudomonas aeruginosa in one patient and Enterococcus faecalis in one patient. In the other 3 patients, causative organisms were not detected. The univariate analysis showed significant differences for present of glenohumeral fracture dislocation (p = 0.004). Logistic regression analysis showed glenohumeral fracture dislocation to be the significant explanatory factor for FRI (odds ratio 12.3, p = 0.0375).

CONCLUSION

This study revealed an infection rate following open reduction and internal fixation of proximal humerus fracture of 1.8% (9 patients) and that Staphylococcus was the most frequent causative organism. Glenohumeral fracture dislocation is a significant risk for postoperative FRI.

The Association of Bohler's Angle With Postoperative Pain and Gender for Displaced Intra-Articular Calcaneal Fracture, Multicenter Retrospective Study-TRON Study

A relationship between Böhler angle (BA) before or after surgery and clinical outcomes remains unclear. This retrospective multicenter cohort study aimed to compare pain and functional outcomes between a group in which the reduction angle was preserved and a group in which the reduction angle was lost during follow-up, and to clarify the risk factors leading to loss of last follow-up BA. From 2014 to 2018, 271 cases of calcaneal fractures were surgically treated at ten facilities. We divided patients into Group L (lost reduction of fracture) and Group P (preserved reduction of fracture). We matched subjects between the 2 groups according to age, sex and BA before surgery and compared American Orthopedic Foot and Ankle Society (AOFAS) score between the groups. We investigated the correlation between the amount of BA loss and postoperative pain. The factors leading to loss of last follow-up BA were examined by logistic regression analysis. Ultimately, 112 patients were eligible. After matching, each group included 38 patients. There was no difference between the 2 groups in total AOFAS score. However, the pain component of AOFAS score at 6 months and 12 months were worse in group L than in group P (p = .011, p = .031, respectively). We also showed a weak correlation between the amount of BA loss and postoperative pain. Logistic regression analysis revealed that female and BA before surgery independently predicted loss of reduction (odds ratios: 4.66, 95% CI: 1.15-18.9 and odds ratios: 0.90, 95% CI: 0.82-0.99, respectively). We clarified that reduction and preservation of BA within its normal range should lead to decrease postoperative pain. Female and lower pre-BA were risk factors leading to loss of reduction of BA in operative treatment of calcaneal fractures.

Predictive factors for mortality after distal femoral fractures in the elderly: A retrospective multicenter (TRON group) study

PURPOSE

This retrospective multicenter study aimed to assess the 1-year mortality rate in elderly patients with distal femoral fractures (DFFs) and identify potential risk factors for mortality.

METHODS

We analyzed 321 patients aged 65 years and older with DFFs treated surgically between 2012 and 2019 in 13 hospitals. Patient demographics and surgical characteristics were extracted from medical records and radiographs. We used univariable and multivariable Cox regression analyses to identify the factors affecting mortality.

RESULTS

The mortality rate for DFFs in elderly patients at 1 year was 9.0%. Multivariable Cox regression analysis revealed older age, male sex, underweight (body mass index [BMI] <18.5 kg/m²), bedridden status, and nursing home residency to be independent predictors for mortality (older age: hazard ratio [HR] 1.07, 95% confidence interval [CI] 1.03-1.11, P<0.001; male sex: HR 3.08, 95% CI 1.23-7.71, P=0.015; underweight: HR 1.93, 95% CI 1.01-3.68, P=0.045; bedridden status: HR 4.59, 95% CI 1.61-13.07, P=0.0042; and nursing home residency: HR 2.63, 95% CI 1.18-5.83, P=0.017). None of the factors associated with surgery including types of fixation, time from initial visit to surgery, blood loss during operation, and operation time was an independent predictor for mortality.

CONCLUSION

The 1-year mortality rate in elderly patients with DFFs was relatively low at 9.0%. Older age, lower BMI, and nursing home residency were associated with mortality after surgery for DFFs. Factors associated with the surgical procedure were not significant predictors.

Low body mass index is a risk factor for increased post-operative mortality and poor functional improvement in distal femur fractures among patients aged over 65: A multicentre (TRON) study

BACKGROUND

Distal femur fractures have been reported to have a mortality rate comparable to hip fractures, but the risk is still unknown. Recent studies have reported that low body mass index (BMI) is a risk factor for mortality in the elderly. We investigated the efficacy of low BMI for predicting the risk of mortality in distal femur fractures in patients aged over 65 within 18 months after injury and its impact on postoperative clinical outcomes and mortality.

METHODS

Data from patients followed for more than six months were obtained from our trauma research group's database. We investigated risk factors for increased mortality using Cox proportional hazards models. We divided the analysed cases into low (<18.5 kg/m²) and high (>18.5 kg/m²) BMI groups. We adjusted the background characteristics of the groups by patient matching, and evaluated the postoperative mortality, complication rate, and knee society score (KSS).

RESULTS

We identified 216 patients, including 58 (26.9%) with low BMI values. Low BMI was an independent risk factor for mortality in all models (Hazard Ratio: 2.9, p = 0.011). The overall survival rate of the low BMI group at 18 months was significantly lower than that of the high BMI group (70.7% vs. 89.1%; p = 0.003). The complication rates of the low BMI and high BMI groups were not significantly different (33.3% vs. 22.2%; p = 0.283). The mean KSS values at 3, 6, and 12 months in the low BMI group was significantly worse than that in the high BMI group (78.7 ± 16.2 vs. 84.8 ± 13.1; p = 0.035, 82.2 ± 16.9 vs. 89.7 ± 8.9; p = 0.005, 86.4 ± 13.0 vs. 91.4 ± 8.4; p = 0.020, respectively).

CONCLUSIONS

Our study indicated that low BMI was independent associated with increased mortality and impaired postoperative functional recovery in distal femur fractures of the elderly patients.

How does intraoperative fracture malalignment affect postoperative function and bone healing following distal femoral fracture?

Aims

Postoperative malalignment of the femur is one of the main complications in distal femur fractures. Few papers have investigated the impact of intraoperative malalignment on postoperative function and bone healing outcomes. The aim of this study was to investigate how intraoperative fracture malalignment affects postoperative bone healing and functional outcomes.

Methods

In total, 140 patients were retrospectively identified from data obtained from a database of hospitals participating in a trauma research group. We divided them into two groups according to coronal plane malalignment of more than 5°: 108 had satisfactory fracture alignment (< 5°, group S), and 32 had unsatisfactory alignment (> 5°, group U). Patient characteristics and injury-related factors were recorded. We compared the rates of nonunion, implant failure, and reoperation as healing outcomes and Knee Society Score (KSS) at three, six, and 12 months as functional outcomes. We also performed a sub-analysis to assess the effect of fracture malalignment by plates and nails on postoperative outcomes.

Results

The rates of nonunion and reoperation in group U were worse than those in group S (25.0% vs 14.3%; 15.6% vs 5.6%), but the differences were not significant (p = 0.180 and p = 0.126, respectively). Mean KSS in group U at all follow-up periods was significantly worse that in group S (75.7 (SD 18.8) vs 86.0 (SD 8.7); p < 0.001; 78.9 (SD 17.2) vs 89.1 (SD 9.8); p < 0.001; 85.0 (SD 11.9) vs 91.1 (SD 7.2); p = 0.002, respectively). In the sub-analysis of plates, mean KSS was significantly worse in group U at three and six months. In the sub-analysis of nails, the rate of reoperation was significantly higher in group U (28.6% vs 5.8%; p = 0.025), and mean KSS at six and 12 months was significantly worse in Group U.

Conclusion

To obtain good postoperative functional results, intraoperative alignment of the coronal plane should be accurately restored to less than 5°.

Cite this article: Bone Jt Open 2022;3(2):165–172.

Plate fixation through the lateral extensile approach versus cannulated screw fixation through the sinus tarsi approach for calcaneal fracture: a multicenter, propensity score-matched TRON study

PURPOSE

For calcaneal fracture, plate fixation through lateral extensive approach (LEP) is the most common procedure performed to achieve anatomic reduction. However, wound complications sometimes occur after LEP. To reduce complications, minimally invasive operative methods with cannulated screw fixation through sinus tarsi approach (STS) were developed. The aim of this multicenter propensity-matched study was to compare the clinical and radiographic outcomes of LEP to those of STS for calcaneal fracture and to evaluate the incidence of postoperative complications including surgical site infection (SSI).

METHODS

We extracted 271 patients with calcaneal fracture undergoing surgery between January 2014 and March 2019 from our multicenter TRON database. We assessed the American Orthopedic Foot and Ankle Society (AOFAS) score at the final follow-up as the clinical outcome. We obtained the Bohler and Preis angles as radiographic parameters and also recorded the complications. We divided the subjects into two groups: LEP group and STS group. To adjust for baseline differences between the groups, a propensity score matching algorithm was used in a 1:1 ratio.

RESULTS

After matching, there were 32 fractures in each group. There was no significant difference between the LEP versus STS group in AOFAS score at final follow-up (90 vs 90 points, p = 0.98) and in the Bohler and Pries angles (19.2 vs. 18.0 degrees, p = 0.74 and 16.0 vs. 17.5 degrees, p = 0.47). The rate of SSI in the LEP group was higher than that in the STS group (21.9% vs. 0.0%, p = 0.01).

CONCLUSION

For calcaneal fracture, STS provides similar fixation effectiveness and functional outcomes as LEP while reducing the likelihood of infection.

Optimal conditions for graft survival and reinnervation of denervated muscles after embryonic motoneuron transplantation into peripheral nerves undergoing Wallerian degeneration

Motoneuron transplantation into peripheral nerves undergoing Wallerian degeneration may have applications in treating diseases causing muscle paralysis. We investigated whether functional reinnervation of denervated muscle could be achieved by early or delayed transplantation after denervation. Adult rats were assigned to six groups with increasing denervation periods (0, 1, 4, 8, 12, and 24 weeks) before inoculation with culture medium containing (transplantation group) or lacking (surgical control group) dissociated embryonic motoneurons into the peroneal nerve. Electrophysiological and tissue analyses were performed 3 months after transplantation. Reinnervation of denervated muscles significantly increased relative muscle weight in the transplantation group compared with the surgical control group for denervation periods of 1 week (0.042% ± 0.0031% vs. 0.032% ± 0.0020%, respectively; p = 0.009), 4 weeks (0.044% ± 0.0069% vs. 0.026% ± 0.0045%, respectively; p = 0.0023), and 8 weeks (0.044% ± 0.0029% vs. 0.026% ± 0.0008%, respectively; p = 0.0023). The ratios of reinnervated muscle contractile forces to naïve muscle in the 0, 1, 4, 8, and 12 weeks transplantation groups were 3.79%, 18.99%, 8.05%, 6.30%, and 5.80%, respectively, indicating that these forces were sufficient for walking. The optimal implantation time for transplantation of motoneurons into the peripheral nerve was 1 week after nerve transection. However, the neurons transplanted 24 weeks after denervation survived and regenerated axons. These results indicated that there is time for preparing cells for transplantation in regenerative medicine and suggested that our method may be useful for paralysed muscles that are not expected to recover with current treatment.

Does surgical treatment for unstable fragility fracture of the pelvis promote early mobilization and improve survival rate and postoperative clinical function?

PURPOSE

This retrospective multicenter study aimed to compare rates of early mobilization and survival and functional outcome of surgical treatment (S) with that of conservative treatment (C) according to each unstable fragility fracture of the pelvis (FFP) classification type with displacement of the posterior component ≥ 5 mm.

METHODS

We analyzed 64 patients with unstable type III and IV FFP who could move and transfer themselves before injury and had ≥ 5 mm displacement of the posterior component. We compared survival rate, early mobilization, walking ability at final follow-up, and complications at admission for each type of surgical and conservative treatment.

RESULTS

Most of the unstable FFP were type IIIa and IVb in the study population. Type III comprised 40 cases (group S:13/group C:27) and type IV comprised 24 cases (group S:7/group C:17). There were no significant differences in 3 month and 1 year survival rates, although group C (III) had the tendency of higher mortality rate (p = 0.08). Mobilization (transferring to a wheelchair) was enabled significantly earlier in group S (III) than in group C (III) (p = 0.02), but in type IV, most patients enabled early mobilization even without surgical intervention. There were no significant differences in hospital complications and walking ability at final follow-up.

CONCLUSION

In this study, the superiority of surgical treatment for unstable FFP was not proven. However, the results suggest that type IVb may be a relatively stable type compared to type III and that type IVb should be considered separately from bilaterally complete unstable sacral fractures due to high-energy trauma.

Primary Radial Nerve Exploration Determined by Ultrasound in Pediatric Supracondylar Humerus Fracture: A Report of Two Cases

We report two pediatric cases of radial nerve palsy caused by supracondylar fracture of the humerus requiring nerve exploration. The children had comparable conditions, palsy types (complete motor and partial sensory) and radiographic findings. The fracture in the first case was managed conservatively with closed reduction and percutaneous pinning but, while the patient eventually recovered from the partial sensory palsy, her motor palsy remained unchanged. In the second case, ultrasound assessment of the nerve prior to fixation indicated that surgical exploration was needed as it revealed tethering on the edge of the proximal fracture fragment. The nerve was released during an open reduction and the patient subsequently recovered from both sensory and motor palsies. Ultrasonography proved essential in the initial clinical assessment by determining how to proceed. We recommend primary nerve exploration when ultrasound findings show entrapment or tethering of the radial nerve.

Innervation of Meissner's corpuscles and Merkel -cells by transplantation of embryonic dorsal root ganglion cells after peripheral nerve section in rats

Transplantation of embryonic motor neurons has been shown to improve motor neuron survival and innervation of neuromuscular junctions in peripheral nerves. However, there have been no reports regarding transplantation of sensory neurons and innervation of sensory receptors. Therefore, we hypothesized that the transplantation of embryonic sensory neurons may improve sensory neurons in the skin and innervate Merkel cells and Meissner's corpuscles. We obtained sensory neurons from dorsal root ganglia of 14-day rat embryos. We generated a rat model of Wallerian-degeneration by performing sciatic nerve transection and waiting for one week after. Six months after cell transplantation, we performed histological and electrophysiological examinations in naïve control, surgical control, and cell transplantation groups. The number of nerve fibers in the papillary dermis and epidermal-dermal interface was significantly greater in the cell transplantation than in the surgical control group. The percent of Merkel cells with nerve terminals, as well as the average number of Meissner corpuscles with nerve terminals, were higher in the cell transplantation than in the surgical control group, but differences were not significant between the two groups. Moreover, the amplitude and latency of sensory conduction velocity were evoked in rats of the cell transplantation group. We demonstrated that the transplantation of embryonic dorsal root ganglion cells improved sensory nerve fiber number and innervation of Merkel cells and Meissner's corpuscles in peripheral nerves.

Muscle spindle reinnervation using transplanted embryonic dorsal root ganglion cells after peripheral nerve transection in rats

OBJECTIVES

Muscle spindles are proprioceptive receptors in the skeletal muscle. Peripheral nerve injury results in a decreased number of muscle spindles and their morphologic deterioration. However, the muscle spindles recover when skeletal muscles are reinnervated with surgical procedures, such as nerve suture or nerve transfer. Morphological changes in muscle spindles by cell transplantation procedure have not been reported so far. Therefore, we hypothesized that transplantation of embryonic sensory neurons may improve sensory neurons in the skeletal muscle and reinnervate the muscle spindles.

MATERIALS AND METHODS

We collected sensory neurons from dorsal root ganglions of 14-day-old rat embryos and prepared a rat model of peripheral nerve injury by performing sciatic nerve transection and allowing for a period of one week before which we performed the cell transplantations. Six months later, the morphological changes of muscle spindles in the cell transplantation group were compared with the naïve control and surgical control groups.

RESULTS

Our results demonstrated that transplantation of embryonic dorsal root ganglion cells induced regeneration of sensory nerve fibre and reinnervation of muscle spindles in the skeletal muscle. Moreover, calbindin D-28k immunoreactivity in intrafusal muscle fibres was maintained for six months after denervation in the cell transplantation group, whereas it disappeared in the surgical control group.

CONCLUSIONS

Cell transplantation therapies could serve as selective targets to modulate mechanosensory function in the skeletal muscle.

Usefulness of CT-based measurement of volar prominence for evaluation of risk of flexor tendon injury following fixation of a distal radius fracture

BACKGROUND

Although some radiographic evaluations of the risk of flexor tendon injury following fixation of a distal radius fracture are useful, these radiographic measurements are limited because of their inability to obtain three-dimensional measurements. We hypothesized that CT-based measurements would be more sensitive indicators for risk estimation than radiography.

METHODS

We retrospectively evaluated the relationship between plate positioning and the incidence of flexor tendon symptoms based on postoperative radiographic and CT-based measurements in 99 hands that were followed up for more than 12 months. We also compared the reproducibility, diagnostic accuracy, and ability to detect the plate-bone gap between radiographic and CT-based measurements. We also assessed the correlation between the volar prominence and plate-bone gap using CT. Multivariable analysis using stepwise logistic regression was performed to identify factors independently associated with tendon rupture or irritation.

RESULTS

In single variable analysis, we found that the volar tilt was significantly smaller and the radiographic plate-to-critical line distance (PCL), CT-PCL, and CT-gap were significantly greater in the group with tendon irritation or rupture. Multivariable logistic regression analysis indicated that the CT-based measurement of the volar prominence is a significantly positive independent predictor of tendon rupture or irritation.

CONCLUSION

CT-based measurement of the volar prominence may be one of the best radiographic predictors of the risk of flexor tendon injury following fixation of a distal radius fracture regardless of the plate type and distal prominence and the extent of rotation. This measurement may assist surgeons when deciding on the need for removal of hardware to decrease the long-term risk of flexor tendon rupture.

A pilot study of social competence assessment using interaction rating scale advanced

Purpose. The purpose of this paper is to clarify the validity of the Interaction Rating Scale Advanced (IRSA) as an evidence-based practical index of social skills. Methods. The participants in our study were 17 high school students. The participants completed the five-minute interaction session and were observed using the IRSA. Their teacher evaluated their social competence based on regular observation in school. Results. The results indicated the high correlation between IRSA scores and teacher's practical evaluation. IRSA can measure social competence with high validity. Conclusion. The IRSA provides further evidence of the fact that in order to study social competence development, it is important to evaluate various features of the interaction like IRSA subscales.

Water chemistry gradient in a degraded bog area

Surface and ground water was sampled in a degraded bog area 36 times during 1993 - 2003 at Five representative points: point E (natural area with Sphagnum as the main vegetal cover), point W (boundary between the natural and degraded areas), point W' (area installed with vinyl sheeting), point WW (area where Sasa thrives), and point NC (area with naturally formed ditches). Analysis of variance (ANOVA) was conducted for parameters measured in surface water and ground water at 0.5, 1.0, 1.5, and 2.0 m depths. "Sampling point" (i.e. locations along the degradation gradient) accounted for most of the variation in surface and ground water chemistry. It accounted for 30-80% of the total variation in pH, electrical conductivity, ammonia, dissolved nitrogen, major cations (Na+, K+, Ca2+, Mg2+), alkalinity and dissolved organic carbon. "Year" accounted for more variation in nitrate, nitrite, chloride, and sulfate than the sampling point did, but the variation in dissolved reactive phosphorus and dissolved phosphorus concentrations was not based on any of the calculated variables.

Effects of hypertonic glucose and amino acid infusions on pancreatic exocrine function

Inhibiting effects of hypertonic glucose and amino-acids on pancreatic exocrine function were studied using mongrel dogs with chronic gastric and pancreatic fistulae. Under the basal stimulation with secretin and pancreoxymin, 20% glucose, 30% glucose and 12% amino acids were given intravenously. Infusion of these substances caused the maximal decreases in pancreatic juice volume and amylase output, to 23% and 11%, respectively (20% glucose), 32% and 29% (30% glucose), and 53% and 42% (12% amino acids). But no significant changes were noted in bicarbonate concentration. When glucose was infused, the rise in levels of blood sugar and IRI was associated with the inhibition of pancreatic exocrine secretion. Aminoacid infusion produced the greatest inhibitory effect on the pancreatic secretion and markedly elevated both the levels of IRI and IRG. Intravenous infusion of glucagon suppressed notably the exocrine function of the pancreas.