Bone mineral density aspects in the femoral neck of hip fracture patients

Applying Machine Learning Analysis Based on Proximal Femur of Abdominal Computed Tomography to Screen for Abnormal Bone Mass in Femur

RATIONALE AND OBJECTIVES

To evaluate the performance of machine learning analysis based on proximal femur of abdominal computed tomography (CT) scans in screening for abnormal bone mass in femur.

MATERIALS AND METHODS

222 patients aged 50 years or older who underwent abdominal CT and dual-energy X-ray absorptiometry scans within 14 days were retrospectively enrolled. The patients were randomly assigned to a training cohort (n = 155) and a testing cohort (n = 67) in a ratio of 7:3. A total of 2288 candidate radiomic features were extracted from the volume region of interest - the left proximal femur of the abdominal CT scans. The most valuable radiomic features were selected using minimum-Redundancy Maximum-Relevancy and the least absolute shrinkage and selection operator to construct the radiomics model. The predictive performance was assessed with receiver operating characteristic curve.

RESULTS

13 features were chosen to establish the radiomics model. The radiomics model using logistic regression displayed excellent prediction performance in distinguishing normal bone mass and abnormal bone mass, with the area under the curve (AUC), accuracy, sensitivity and specificity of 0.917 (95% CI, 0.867-0.967), 0.826, 0.935 and 0.780 in the training cohort. The testing cohort indicated a better performance with AUC, accuracy, sensitivity and specificity of 0.963 (95% CI, 0.919-0.999), 0.851, 0.923 and 0.889.

CONCLUSION

The radiomics model based on proximal femur of abdominal CT scans had a high predictive performance to identify abnormal bone mass in femur, which can be used as a tool for opportunistic osteoporosis screening.

Osseointegration of a hydroxyapatite-coated stem in femoral neck fractures in the over-80 s

PURPOSE

In the over-80 s, femoral bone is often osteoporotic and unlikely to be conducive to periprosthetic bone rehabitation. This observation often leads to cemented fixation for hemiarthroplasty in femoral neck fracture. Hydroxyapatite is a bioactive coating that has already demonstrated its osteoinductive properties. Our hypothesis is that hydroxyapatite enables prosthetic osseointegration in patients over 80, as well as periprosthetic cortical thickening. The objective was to evaluate the osseointegration of a hydroxyapatite-coated femoral stem in femoral neck fractures in the over-80 s, and the evaluation of the periprosthetic bone regeneration permitted by hydroxyapatite.

METHODS

This was a retrospective study. Osseointegration and periprosthetic bone regeneration were assessed on pre-operative, immediate post-operative and last follow-up radiographs with Engh score, O-SS score, cortical index, Canal Bone Ration (CBR) and Canal Fill Ratio (CFR).

RESULTS

One hundred and forty-six patients were included. At last follow-up, 99.3% (n = 145) of stems were osseointegrated. The mean Engh score was 19.9 [SD 3.1]. The mean O-SS score was 19.1 [SD 2.4], corresponding to very good osseointegration. The mean CBR at last follow-up was 0.48 [SD 0.07], corresponding to a non-osteoporotic femur. There was a significant difference with pre-operative CBR (p < 0,001). The pre-operative cortical index and the index at the last follow-up were significantly different for all levels of measurement (p < 0,001). The CFR at last follow-up was also significantly different with the post-operative CFR (p < 0,001).

CONCLUSION

This study shows the value of using a hydroxyapatite-coated stem on senile, osteoporotic bone to improve cortical thickness along the entire length of femoral bone.

Site-Specific Differences in Bone Mineral Density of Proximal Femur Correlate with the Type of Hip Fracture

The aim of this study was to investigate whether site-specific differences in bone mineral density (BMD) of proximal femur correlate with the type of hip fracture using quantitative computed tomography. Femoral neck (FN) fractures were classified as nondisplaced or displaced subtypes. Intertrochanteric (IT) fractures were classified as A1, A2, or A3. The severe hip fractures were identified as displaced FN fractures or unstable IT fractures (A2 and A3). In total, 404 FN fractures (89 nondisplaced and 317 displaced) and 189 IT fractures (76 A1, 90 A2, and 23 A3) were enrolled. Areal BMD (aBMD) and volumetric BMD (vBMD) were measured in the regions of total hip (TH), trochanter (TR), FN, and IT of the contralateral unfractured femur. IT fractures exhibited lower BMD than FN fractures (all p ≤ 0.01). However, unstable IT fractures had higher BMD compared with stable ones (p < 0.01). After adjusting for covariates, higher BMD in TH and IT were associated with IT A2 (A1 vs. A2: odds ratios (ORs) from 1.47 to 1.69, all p < 0.01). Low bone measurements were risk factors for stable IT fractures (IT A1 vs. FN fracture subtypes: ORs from 0.40 to 0.65, all p < 0.01). There are substantial site-specific differences in BMD between IT fractures A1 and displaced FN fractures. Higher bone density was associated with unstable IT fracture when compared with stable ones. The understanding of biomechanics of various fracture types could help to improve the clinical management of these patients.

Age related changes in the bone microstructure in patients with femoral neck fractures

BACKGROUND

The risk of femoral neck fracture progressively increases with age. However, the reasons behind this consistent increase in the fracture risk can't be completely justified by the decrease in the bone mineral density. The objective of this study was to analyze the correlation between various bone structural features and age.

STUDY DESIGN & METHODS

A total of 29 consecutive patients who suffered an intracapsular hip fracture and underwent joint replacement surgery between May 2012 and March 2013 were included in this study. A 2 cm × 1 cm Ø cylindrical trabecular bone sample was collected from the femoral heads and preserved in formaldehyde. Bone mineral density (BMD), microarchitecture, organic content and crystallography were analyzed using a Dual-energy X-ray absorptiometry scan, micro-CT scan, and high resolution magic-angle-spinning-nuclear magnetic resonance (MAS-NMR), respectively. Statistical correlations were made using Spearman´s or Pearson´s correlation tests depending on the distribution of the continuous variables.

RESULTS

The mean patient age was 79.83 ± 9.31 years. A moderate negative correlation was observed between age and the hydrogen content in bone (¹H), which is an indirect estimate to quantify the organic matrix (r = -0.512, p = 0.005). No correlations were observed between BMD, trabecular number, trabecular thickness, phosphorous content, apatite crystal size, and age (r = 0.06, p = 0.755; r = -0.008, p = 0.967; r = -0.046, p = 0.812; r = -0.152, p = 0.430, respectively). A weak positive correlation was observed between Charlson´s comorbidity index (CCI) and c-axis of the hydroxiapatite (HA) crystals (r = -0.400, p = 0.035).

CONCLUSION

The femoral head relative protein content progressively decreases with age. BMD was not correlated with other structural bone parameters and age. Patients with higher comorbidity scores had larger HA crystals. The present results suggest that the progressive increase in the hip fracture risk in elderly patients could be partially explained by the lower bone protein content in this age group.

A Comparative Study of Intramedullary Nail Strengthened with Auxiliary Locking Plate or Steel Wire in the Treatment of Unstable Trochanteric Fracture of Femur

Objective

To compare the clinical outcomes of unstable femoral trochanteric fracture treated by proximal femoral intramedullary nail enhanced with lateral locking plate versus cerclage steel wire.

Methods

A retrospective study was conducted on 83 patients who received open reduction and internal fixation with proximal femoral intramedullary nail combined with lateral enhanced fixations for unstable femoral trochanteric fractures from March 2015 to January 2017 in our hospital. Of these patients, 39 received the lateral enhanced fixation with locking plate, while the remaining 44 had cerclage wire as additional fixation. The clinical data were compared between the two groups.

Results

All the patients in the study had surgical procedures performed smoothly. Although the plate group had significantly longer operation times and significantly higher hospitalization expenses than the wire group (P < 0.05), no statistically significant differences in intraoperative blood loss and hospital stay were proved between the groups (P > 0.05). The follow‐up period lasted for 12–24 months with an average of (16.81 ± 2.92) months. The plate group returned to full‐weight bearing significantly earlier than the wire group (P < 0.05). The Harris Hip Score (HHS) significantly increased in both groups over time postoperatively (P < 0.05). The plate group achieved a higher HHS than the wire group, which was statistically significant at 3 months (P < 0.05), whereas it became insignificant at 6 and 12 months postoperatively (P > 0.05). Regarding radiographic assessment, an excellent rate of fracture reduction was proved in 71.79% of the plate group, compared to 45.45% of the wire group, which was statistically significant (P < 0.05). In addition, fracture healing was achieved significantly earlier in the plate group than the wire group (P < 0.05); nevertheless, no statistically significant difference was noted in neck‐shaft angle at the latest follow‐up between the two groups (P > 0.05). At the latest follow‐up, two cases of implant loosening and two cases of coxa varus were found in the plate group, while one case of femoral head necrosis and three cases of coxa varus were revealed by radiographs in the wire group.

Conclusion

The cerclage wire has benefits of saving time and operation costs; however, the locking plate has the advantages of improving fracture reduction quality, shortening time to full weight bearing and fracture healing, and improving hip function recovery due to the lateral additional fixations to proximal femoral intramedullary nail for unstable trochanteric fractures.

Bench-to-bedside strategies for osteoporotic fracture: From osteoimmunology to mechanosensation

Osteoporosis is characterized by a decrease in bone mass and strength, rendering people prone to osteoporotic fractures caused by low-energy forces. The primary treatment strategy for osteoporotic fractures is surgery; however, the compromised and comminuted bones in osteoporotic fracture sites are not conducive to optimum reduction and rigid fixation. In addition, these patients always exhibit accompanying aging-related disorders, including high inflammatory status, decreased mechanical loading and abnormal skeletal metabolism, which are disadvantages for fracture healing around sites that have undergone orthopedic procedures. Since the incidence of osteoporosis is expected to increase worldwide, orthopedic surgeons should pay more attention to comprehensive strategies for improving the poor prognosis of osteoporotic fractures. Herein, we highlight the molecular basis of osteoimmunology and bone mechanosensation in different healing phases of elderly osteoporotic fractures, guiding perioperative management to alleviate the unfavorable effects of insufficient mechanical loading, high inflammatory levels and pathogen infection. The well-informed pharmacologic and surgical intervention, including treatment with anti-inflammatory drugs and sufficient application of antibiotics, as well as bench-to-bedside strategies for bone augmentation and hardware selection, should be made according to a comprehensive understanding of bone biomechanical properties in addition to the remodeling status of osteoporotic bones, which is necessary for creating proper biological and mechanical environments for bone union and remodeling. Multidisciplinary collaboration will facilitate the improvement of overall osteoporotic care and reduction of secondary fracture incidence.

Incidence of bone protection and associated fragility injuries in patients with proximal femur fractures

OBJECTIVES

Our aim was to investigate whether patients presenting with fragility fractures of the proximal femur are receiving osteoporosis treatment and to assess the number of other fragility fractures they have sustained prior to admission.

METHODS

All patients presenting to our institution with fragility fractures of the proximal femur within an 18-month period (January 2012-August 2013) were included. Patient demographics; fracture classification (AO/OTA); American Society of Anesthesiologists (ASA) grade; Abbreviated Mental Test Score (AMTS) on admission; type of operation; time to operation; peri-operative complications; length of hospital stay (LOS); walking status; osteoporotic medication; Dual-energy X-ray absorptiometry (DEXA) results; additional fragility fractures; and mortality were collected and analysed.

RESULTS

A total of 1004 patients (278 male) met the inclusion criteria and were included into the study. The mean age was 82.01 years and mean LOS was 19.54days. Fifty-four per cent of the patients were admitted from their own homes whereas 43% were capable to walk indoors without any aids before their injury. Mean time to surgery was 2.06days (Median: 1.31, range: 0-26days). Three hundred and six patients (30.5%) had at least another fragility fracture before the index episode (mean 1.40 fractures; SD: 0.71 fractures; range: 1-6 fractures). Only 16.4% were under complete osteoporosis treatment on admission, defined as receiving calcium with vitamin D and a bisphosphonate or an alternative agent. When we compared patients without a history of a previous fragility fracture (Group A) and patients with at least another previous fragility fracture (Group B), we found that patients in Group B had a significantly lower AMTS score, lower bone mineral density (BMD) as evident on the DEXA scan, an inferior mobility before admission and a higher incidence of extracapsular fractures (p<0.05). On discharge, patients in Group B had a higher chance of receiving complete bone protection compared to group A (27.9% versus 41.7%; p<0.01). Following discharge, 11.2% of the patients sustained an additional fragility fracture. The mean time from the index episode to the additional fracture was 0.65 years, whilst these injuries were more frequent in Group B (RR=1.638; p<0.05).

CONCLUSION

Patients presenting with a hip fracture are generally under-treated for osteoporosis. Post-operative assessment by a designated geriatrician and use of a standardised protocol is of paramount importance for reducing the risk of additional fragility fractures. Additionally, screening of the elderly population for identifying the patients who suffer from osteoporosis can potentially reduce the risk of sustaining a further fragility fracture.

Blood loss in trochanteric fractures: multivariate analysis comparing dynamic hip screw and Gamma nail

INTRODUCTION

Anaemia in patients with trochanteric fracture is associated with increased morbidity and mortality and it is an independent risk factor for functional mobility of patients. Several authors have reported the blood loss following operative treatment comparing different fixation systems but few authors have evaluated many associated variables that could influence the perioperative blood loss.

PURPOSE

To evaluate the blood loss in patients that had their trochanteric fracture stabilized with dynamic hip screw (DHS) or Gamma nail. Multivariate analysis of different variables that can influence blood loss was carried out (type of fracture, antiaggregant or anticoagulant therapy, time to surgery). The hypothesis was that there is no difference in terms of blood loss in patients with trochanteric fracture treated with DHS or Gamma nail considering all these variables.

MATERIALS & METHODS

Perioperative blood loss was evaluated in 417 consecutive patients treated for trochanteric fracture with DHS or Gamma nail between January 2010 and March 2013. The perioperative blood loss was calculated using the Lisander formula modified by Foss-Kehlet based on pre- and post-operative haemoglobin values and transfusion rates. Univariate and multivariate analysis were performed integrating the following variables: type of fracture (A1 vs A2), antiaggregant/anticoagulant therapy vs no therapy, time to surgery (<24 vs >24 hours from trauma), type of implant (DHS vs Gamma nail).

RESULTS

A significant blood loss (p <0.05) was observed between A1 and A2 fracture types (1247ml vs 1796.7ml), antiaggregant/anticoagulant therapy and no therapy (1592.7ml vs 1470.2ml), time-to-surgery <24 and >24 hours from trauma (1584.4ml vs 1323.9ml), DHS and Gamma nail (894.7ml vs 1720.6ml). At multivariate analysis, in the A1 fracture groups the DHS showed a significant lower blood loss compared to Gamma nail (p < 0.05).

CONCLUSIONS

According to the perioperative blood loss, DHS should be used in A1 fractures while Gamma nail can be taking in account for the unstable A2 fractures.

Augmentation of intramedullary nailing in unstable intertrochanteric fractures using cerclage wire and lag screws: a comparative study

BACKGROUND

Unstable intertrochanteric fractures present a challenge to orthopaedic surgeons, with varied geometry of the fractures and a wide choice of implants and techniques. The patients are usually osteoporotic, with multiple co-morbidities and poor tolerance for complications and re-operations. Lateral wall reconstruction and stability of the trochanteric fragments are considered important in providing a better outcome of these difficult injuries. We present a technique of lateral wall and trochanteric reconstruction using Cerclage wires and lag screws in the greater trochanter in addition to intramedullary nailing, and the radiological and functional outcome of this technique of augmentation.

MATERIALS AND METHODS

This prospective study includes 154 patients from 2010 to 2015 presenting to the institute with an unstable intertrochanteric fracture. They were sequentially operated with intramedullary nailing (IMN) and augmentation with cerclage wire and/or Anteroposterior screw in greater trochanter, and 77 patients with IMN only. Operating time and need for blood transfusion post-surgery were documented. Patients were followed up for minimum of 12 months and radiological union time, complications and functional outcome using Harris Hip Score were noted at 1 year. Statistical analysis was performed to compare the results in both groups RESULTS: The mean union was 3.6 months in group A and 4.1 months in group B, with no statistically significant difference. The operating time needed for augmentation was 10 minutes more than IMN only. Blood transfusion was not required in any case. The incidence of complications like screw cut out, back out and non-union was lower in augmented group, and good functional outcome was greater in the augmented group which was statistically significant. The reoperation rate was lower in augmented group.

CONCLUSIONS

This new technique of augmentation of fixation of intramedullary nail in unstable trochanteric fractures using cerclage wires and lag screws for lateral wall reconstruction is useful in reducing complications of the procedure and provides good radiological and functional outcome. It requires little additional operating time with minimal blood loss and soft tissue injury.

Outcomes of dynamic hip screw augmented with trochanteric wiring for treatment of unstable type A2 intertrochanteric femur fractures

BACKGROUND

Posteromedial and greater trochanteric fragments are a major cause of telescoping and medialization of the femoral shaft in an unstable intertrochanteric fracture. This leads to significant limb shortening, fracture collapse in varus position and implant failure, which can be prevented by trochanteric wiring in addition to dynamic hip screw (DHS) fixation. The purpose of our study is to assess the outcomes of DHS augmented with trochanteric wiring in unstable type A2 intertrochanteric fractures.

MATERIALS AND METHODS

One hundred and two retrospective cases of unstable intertrochanteric fractures treated with DHS between January 2010 and December 2015 with a minimum follow-up period of 12 months were reviewed. Out of 102 cases, 28 were treated with DHS and derotation screw alone (Group A), while in rest 74 cases trochanteric wiring was used as an augmentation to DHS and derotation screw (Group B). Patients were evaluated clinically for range of motion, Harris hip score and Oxford hip score. Radiologically, fracture reduction, change in neck shaft angle and neck length ratio in comparison to opposite hip and union status of greater trochanter were assessed.

RESULTS

The mean age of the patients at the time of surgery was 72 years (range 23-94 years) with 48 males and 54 females. The mean follow-up period was 20 months (range 12-48 months). The Harris hip score, Oxford hip score, shortening, attainment of weight bearing and change in neck shaft angle was not significantly different between the two groups (all p values >0.05). Incidence of greater trochanter nonunion was greater in group A (17.85%) as compared to group B (6.75%). We found significant association between occurrence of limp with varus change in neck shaft angle, decrease in neck length ratio and greater trochanteric non-union (all p values <0.05). We had 7 complications, one superficial infection, one deep vein thrombosis, 4 screw cut out and one deep infection treated with implant removal.

CONCLUSION

DHS augmented with trochanteric wiring in unstable intertrochanteric fractures gives similar result to group without no wiring, although greater trochanter non-union rate was more in the latter group. Limp can be prevented by anatomical or valgus fixation, augmentation of DHS to support posteromedial and greater trochanteric fragments and delayed weight bearing.

DHS osteosynthesis with internal bone grafting in unstable delayed presented intracapsular neck femur fractures

OBJECTIVES

The aim of this study was to assess fracture union and complications following use of dynamic hip screw (DHS) with internal bone grafting in treatment of unstable delayed presented intracapsular neck femur fractures in patients younger than 65 years of age.

MATERIAL AND METHODS

Thirty two patients with displaced intracapsular neck femur fractures(Garden III and IV, Pauwels III, with comminution) with delayed presentation (15-60 days) in the 45-65 year age group (mean 54.4±10.2 years) were included in this study. All patients were treated with dynamic sliding hip screw with closed cancellous bone grafting through a tunnel of a triple reamer. The average time to union was 3.8 months (3-5 months). Satisfactory union was achieved in all patients except two. One case developed avascular necrosis of the femoral head. Other complications were coxa vara in two, shortening of less than 10mm in three cases but there were no cases of infection or implant failure. Excellent results were achieved in 27, good/fair in 4 and poor in 1 patient.

CONCLUSION

Osteosynthesis with DHS and primary cancellous bone grafting in indicated cases is a simple, providing biological stimulation for early union. Failure in a particular case can be treated with any appropriate second procedure.

Bone mechanical properties and changes with osteoporosis

This review will define the role of collagen and within-bone heterogeneity and elaborate the importance of trabecular and cortical architecture with regard to their effect on the mechanical strength of bone. For each of these factors, the changes seen with osteoporosis and ageing will be described and how they can compromise strength and eventually lead to bone fragility.

Understanding the pathogenesis of hip fracture in the elderly, osteoporotic theory is not reflected in the outcome of prevention programmes

Hip fractures are an acute and worsening public health problem. They mainly affect elderly people, a population group that is highly vulnerable to disease and accidents, and to falls in particular. Although it has been suggested that osteoporosis is the cause of hip fractures, they mainly occur after a fall has been suffered. The underlying causes of a fall are not related to osteoporosis, although pharmaceutical companies have coined the term “osteoporotic fracture” for hip fractures in the elderly. Drug treatments for osteoporosis have not diminished the frequency of these injuries, nor have they prevented the occurrence of a subsequent fracture. Since pharmaceutical interests require osteoporosis to be considered a disease, rather than a normal condition of senescence, they go further by assuming that treatment for osteoporosis is essential, and that this policy will diminish the incidence of hip fractures. On the other hand, the origin and treatment of conditions that may be conducive to provoking falls are very difficult to elucidate. In this paper, we consider some of the medical and social problems that arise in this area, as well as conflicts of interest regarding the aetiopathogenesis and prevention of hip fracture, and propose a new paradigm for the prevention of falls.