Osteocyte mitochondria regulate angiogenesis of transcortical vessels.

Transcortical vessels (TCVs) provide effective communication between bone marrow vascular system and external circulation. Although osteocytes are in close contact with them, it is not clear whether osteocytes regulate the homeostasis of TCVs. Here, we show that osteocytes maintain the normal network of TCVs by transferring mitochondria to the endothelial cells of TCV. Partial ablation of osteocytes causes TCV regression. Inhibition of mitochondrial transfer by conditional knockout of Rhot1 in osteocytes also leads to regression of the TCV network. By contrast, acquisition of osteocyte mitochondria by endothelial cells efficiently restores endothelial dysfunction. Administration of osteocyte mitochondria resultes in acceleration of the angiogenesis and healing of the cortical bone defect. Our results provide new insights into osteocyte-TCV interactions and inspire the potential application of mitochondrial therapy for bone-related diseases.

Biomechanical study of a new rim plate fixation strategy for two kinds of posterolateral depression patterns of tibial plateau fractures: a finite element analysis.

PURPOSE: The biomechanical capacity of "Barrel Hoop Plate (BHP)" in the treatment of the posterolateral tibial plateau (PL) depression fractures remains unknown. In this study, two kinds of posterolateral tibial plateau depression models involving mild slope-type depression fracture (MSDF) and local sink hole-type depression fracture (LSDF) were created to test and compare the biomechanical capacities of BHP with the other two conventional fixations (Anterolateral Plate and Posterolateral Plate, ALP and PLP) by finite element analysis. METHODS: The 3D models of three kinds of plate-screw systems and the two kinds of PL-depression models (MSDF and LSDF) were created. An axial force of 400N was applied from the distal femur to the tibial plateau. The maximal displacements of the posterolateral fractures (PLFs), the distribution on the PLFs articular surface and key points displacements were measured. Stresses in the fixation complex including the maximal Equivalent (von-Mises) Stress of implants, the max shear stress of PLFs and stiffness of the fixation were calculated. RESULTS: The maximal displacement of MSDF was least in Group BHP. The maximal displacement of LSDF was least in Group ALP. In MSDF, BHP showed the best rim fix effect in MSDF, but unsatisfactory results in LSDF. In both MSDF and LSDF, the greatest max Equivalent Stress of the plate and the screw occurred in the PLP system. ALP and BHP showed a comparable stiffness in MSDF and ALP had the strongest stiffness in the fixation of LSDF. CONCLUSIONS: In MSDF, the BHP has the best biomechanical capacity, especially in displacements of key points such as the PL rim, fracture line, and depression center. In LSDF, the ALP system shows the best biomechanical effect. Although the PLP has the best fixation effect on the posterior wall, it is not suitable for PL-depression fracture fixation.

Specific types of femoral head fractures: be alert for pre-, intra-, and post-operative ipsilateral femoral neck fractures following fracture-dislocation of the femoral head.

PURPOSE: Ipsilateral femoral head and neck fractures (iFHNFs) are rare types of fractures that confer extremely poor prognosis among femoral head fractures (FHFs). Owing to the rarity of FHFs, it is challenging to diagnose iFHNFs. In addition, the clinical features of iFHNF have not yet been comprehensively elucidated. Therefore, this retrospective study aimed to summarize and analyze the clinical characteristics of iFHNF using a clinical diagnostic simulation based on a prospectively maintained database. METHODS: Clinical data of consecutive patients with FHFs, including gender, age, injury side, and associated injuries, were collected and analyzed from a prospectively maintained orthopedic database at a large level-I trauma center for a clinical diagnostic simulation. Patients were stratified according to the presence or absence of iFHNF. Moreover, propensity score matching (PSM) was used to create 1:1 age- and gender-matched couples. Lastly, clinical factors were compared and identified between the two groups before and after matching. RESULTS: A total of 218 FHF patients were included. Fifteen patients were diagnosed with ipsilateral femoral neck fractures (iFNFs), including preoperative, intraoperative, and postoperative types. There were 177 male and 41 female patients, with a mean age of 40.0 ± 16.5 years. The incidence of two factors, namely acetabular fracture and posterior hip dislocation, were significantly different between the two groups (P < 0.05). Following PSM, 15 pairs of patients were generated. Comparisons revealed that the incidence of posterior hip dislocation was significantly different between the two groups (P < 0.05). CONCLUSIONS: There were three types of iFHNFs. In the context of FHFs, posterior hip dislocation was associated with iFNFs. Thus, surgeons should remain vigilant, not only intraoperatively but also postoperatively, for iFNFs following FHF and concomitant posterior hip dislocation. LEVEL OF EVIDENCE: Diagnostic level IV.

Bone Grafting Can Promote the Prognosis of Displaced Femoral Neck Fractures: A Follow-up of the Clinical Significance of Bone Defects.

Background: Femoral neck fractures (FNFs) comprise a large proportion of osteoporotic fractures in Asia. However, the full range of prognostic variables that affect prognosis remains unclear. Here, we aimed to determine whether the severity of bone defects at the fracture site and other variables impact the prognosis of displaced FNFs. Methods: We evaluated the incidence of FNF internal fixation failures at regular intervals after surgery in data collected retrospectively. Digital Imaging and Communications in Medicine (DICOM) magnetic resonance imaging data of the displaced FNFs of 204 patients (> 20 years old; mean age, 52.3 years; men, 55.4%) who underwent internal fixation were used to construct three-dimensional (3D) virtual models of the femoral neck region. We calculated the position and volume of bone defect (VBD) using our independently developed algorithm and Mimics software. Each participant was followed up for at least 24 months; complications were noted and correlated with VBD and demographic and clinical variables. Results: On the basis of VBD values calculated from virtual reduction models, 57 patients were categorized as having a mild defect, 100 as having a moderate defect, and 47 as having a severe defect. Age (p = 0.046) and VBD (p < 0.001) were significantly correlated with internal fixation failure. Multivariate analysis revealed that severe bone defects were associated with internal fixation failure (adjusted odds ratio [aOR], 23.073; 95% confidence interval [CI], 2.791-190.732) and complications (aOR, 8.945; 95% CI, 1.829-43.749). In patients with a severe defect, bone grafting was inversely associated with internal fixation failure (aOR, 0.022; 95% CI, 0.002-0.268) and complications (aOR, 0.023; 95% CI, 0.002-0.299). Conclusions: Bone defect severity was associated with internal fixation failure and other complications. For young adults with large VBDs, bone grafting of the defect can reduce the risk of internal fixation failure. These results provide useful new quantitative information for precisely classifying displaced FNFs and guiding subsequent optimal treatments.

Can "In-Out-In" posterosuperior screws meet nutrient foramina in patients with femoral neck fractures?

BACKGROUND: The "In-Out-In" (IOI) posterosuperior screw was common in screw fixations of femoral neck fractures. The impacts of the IOI screw on the blood supply of the femoral head have not yet been clarified. The nutrient foramen was damaged when the screw was present in their corresponding cortex surface. This study aimed to evaluate the damage degrees of the nutrient foramina in the femoral neck as the IOI posterosuperior screw was placed in different posterosuperior locations. METHODS: One hundred and eight unpaired dry human cadaveric proximal femurs were scanned by a three-dimensional scanner. Digital data obtained from the proximal femur surface were employed for subsequent analysis. All nutrient foramina in the femoral neck were identified and marked in each subject. A simulation of the anteroposterior, lateral, and axial views was then performed, and regions of interest (ROIs) for IOI posterosuperior screws, with 6.5 mm diameter, were determined in the posterosuperior femoral neck on the axial graphs. Nutrient foramina were counted and analyzed in ROIs and femoral neck, and its damage from the IOI posterosuperior screw was also calculated in different conditions of screw placement. Paired t-tests were used for comparative analyses before and after damage. RESULTS: Most nutrient foramina were located in the subcapital region and the least in the basicervical region in the femoral neck, while the most were located in the transcervical and the least in the subcapital in the ROIs. In addition, most nutrient foramina in ROIs were located in the superior-posterior area of the femoral neck. There were four main locations of IOI posterosuperior screws where the decrease in the nutrient foramina was statistically significant (P < 0.01). The risk zone determined by these locations was located in a posterosuperior square of ROIs with an edge length of 9.75 mm. CONCLUSION: To minimize iatrogenic damage to the blood supply of the femoral head, screw positions could be assessed in anteroposterior and lateral radiographs using a risk zone. The IOI posterosuperior screw in ROIs can be applied to fix femoral neck fractures when feasible in clinical practice. This study could provide surgeons with more alternatives for screw placement in the posterosuperior femoral neck.

Clinical Evaluation of Femoral Head Fractures: Which Classification Systems Have the Best Universality, Reliability, and Reproducibility?

BACKGROUND: Femoral head fractures are rare but potentially disabling injuries, and classifying them accurately and consistently can help surgeons make good choices about their treatment. However, there is no consensus as to which classification of these fractures is the most advantageous; parameters that might inform this choice include universality (the proportion of fractures that can be classified), as well as, of course, interobserver and intraobserver reproducibility. QUESTIONS/PURPOSES: (1) Which classification achieves the best universality (defined as the proportion of fractures that can be classified)? (2) Which classification delivers the highest intraobserver and interobserver reproducibility in the clinical CT assessment of femoral head fractures? (3) Based on the answers to those two questions, which classifications are the most applicable for clinical practice and research? METHODS: Between January 2011 and January 2023, 254 patients with femoral head fractures who had CT scans (CT is routine at our institution for patients who have experienced severe hip trauma) were potentially eligible for inclusion in this study, which was performed at a large Level I trauma center in China. Of those, 9% (23 patients) were excluded because of poor-quality CT images, unclosed physes, pathologic fractures, or acetabular dysplasia, leaving 91% (231 patients with 231 hips) for analysis here. Among those, 19% (45) were female. At the time of injury, the mean age was 40 ± 17 years. All fractures were independently classified by four observers according to the Pipkin, Brumback, AO/Orthopaedic Trauma Association (OTA), Chiron, and New classifications. Each observer repeated his classifications again 1 month later to allow us to ascertain intraobserver reliability. To evaluate the universality of classifications, we characterized the percentage of hips that could be classified using the definitions offered in each classification. The kappa (κ) value was calculated to determine interrater and intrarater agreement. We then compared the classifications based on the combination of universality and interobserver and intraobserver reproducibility to determine which classifications might be recommended for clinical and research use. RESULTS: The universalities of the classifications were 99% (228 of 231, Pipkin), 43% (99 of 231, Brumback), 94% (216 of 231, AO/OTA), 99% (228 of 231, Chiron), and 100% (231 of 231, New). The interrater agreement was judged as almost perfect (κ 0.81 [95% CI 0.78 to 0.84], Pipkin), moderate (κ 0.51 [95% CI 0.44 to 0.59], Brumback), fair (κ 0.28 [95% CI 0.18 to 0.38], AO/OTA), substantial (κ 0.79 [95% CI 0.76 to 0.82], Chiron), and substantial (κ 0.63 [95% CI 0.58 to 0.68], New). In addition, the intrarater agreement was judged as almost perfect (κ 0.89 [95% CI 0.83 to 0.96]), substantial (κ 0.72 [95% CI 0.69 to 0.75]), moderate (κ 0.51 [95% CI 0.43 to 0.58]), almost perfect (κ 0.87 [95% CI 0.82 to 0.91]), and substantial (κ 0.78 [95% CI 0.59 to 0.97]), respectively. Based on these findings, we determined that the Pipkin and Chiron classifications offer near-complete universality and sufficient interobserver and intraobserver reproducibility to recommend them for clinical and research use, but the other classifications (Brumback, AO/OTA, and New) do not. CONCLUSION: Based on our findings, clinicians and clinician-scientists can use either the Pipkin or Chiron classification systems to classify femoral head fractures based on CT images, with equal confidence. It seems unlikely that any new classifications will substantially outperform these, and the other available systems either lacked sufficient universality or reproducibility to recommend them for general use. LEVEL OF EVIDENCE: Level III, diagnostic study.

Precise measurement of microwave polarization using a Rydberg atom-based mixer.

A Rydberg atom-based mixer has opened up a new method to characterize microwave electric fields such as the precise measurement of their phase and strength. This study further demonstrates, theoretically and experimentally, a method to accurately measure the polarization of a microwave electric field based on a Rydberg atom-based mixer. The results show that the amplitude of the beat note changes with the polarization of the microwave electric field in a period of 180 degrees, and in the linear region a polarization resolution better than 0.5 degree can be easily obtained which reaches the best level by a Rydberg atomic sensor. More interestingly, the mixer-based measurements are immune to the polarization of the light field that forms the Rydberg EIT. This method considerably simplifies theoretical analysis and the experimental system required for measuring microwave polarization using Rydberg atoms and is of interest in microwave sensing.

[Disastrous triad of femoral head:femoral neck fracture meeting fracture-dislocation of femoral head].

Femoral head and ipsilateral femoral neck fractures are serious and complicated injuries, which usually yield unsatisfactory results using conventional hip-preserving surgery. The key point of the management and prognosis mainly lies in femoral neck fractures. An apparent and consecutive relationship exists between femoral neck fractures and femoral head fracture-hip dislocation in such injuries. It is believed that disastrous triad of femoral head (DTFH) could summarize these specific injuries, and reflect the injury mechanism and prognostic characteristics. Based on our clinical observation and literature review, DTFH could be divided into three subgroups:TypeⅠ, common DTFH, in which femoral neck fractures occur following femoral head fractures-hip dislocation due to the same trauma; TypeⅡ, iatrogenic DTFH, in which femoral neck fractures come out in the caring process of femoral head fractures-hip dislocation; Type Ⅲ, stressed DTFH, in which femoral neck fractures occur after the management of femoral head fractures-hip dislocation. In the scenario, the line of femoral neck fractures locates distally to the femoral head fractures. Herein, we will discuss clinical characteristics of these types of DTFH.

[Review of closed reduction techniques for femoral neck fracture].

For patients with femoral neck fractures who plan to undergo internal fixation, satisfied alignment of fracture ends is an important prerequisite for internal fixation stability and fracture healing. There are many reports on the reduction methods of displaced femoral neck fractures, which can be summarized into three categories:First, the solely longitudinal traction of lower limbs, supplemented by other manipulations such as rotation and compression; Second, the resultant force formed by the longitudinal traction of lower limbs and the lateral traction;the third is accomplished by vertical traction in the axis of femur with hip joint flexed. Each reduction method has its own advantages, but no single method can be applied to all fracture displacement. In this paper, some classical reduction techniques in the literatures are briefly reviewed. It is hoped that clinicians will not be limited to a certain reduction method, they should analyze the injury mechanism and fracture displacement process according to the morphology features and flexibly select targeted reduction methods to improve the success rate of closed reduction of femoral neck fracture.

Relative efficacy of three different tendon repairs in complete flexor digitorum profundus laceration in Zone I: A randomized controlled study.

Hand flexor tendon injuries are common and biomechanically challenging to achieve good functional outcomes. Several approaches using the Pennington-modified Kessler repair technique have been attempted, but high-level evidence is still lacking. Here, we evaluated the relative efficacy of three versions of the Pennington-modified Kessler technique in repairing complete flexor digitorum profundus (FDP) laceration in Zone 1. We conducted a 2-year, single-center, double-blind, randomized clinical trial involving 85 patients with 105 digits enrolled between June 1, 2017 and January 1, 2019. Eligible participants were 20-60 years of age and underwent tendon repair in the acute phase for complete FDP laceration distal to the insertion of the superficial flexor tendon. The digits were randomized 1:1:1 to three treatment groups: (1) Pennington-modified Kessler repair; (2) Pennington-modified Kessler repair followed by circumferential tendon suture; or (3) Pennington-modified Kessler repair followed by circumferential epitenon suture. The primary endpoint was total active range of motion (TAROM) at 2 years after the initial surgery. The secondary endpoint was the reoperation rate. Compared with group 1, both techniques for peripheral suture were associated with a decrease in TAROM at 2 years after surgery. The total reoperation rates of the three groups were 11.4%, 18.2%, and 17.6%, and we found no significant differences among the three groups possibly due to the limited sample size. Unexpectedly, among participants with complete FDP laceration in Zone I, both circumferential-tendon and circumferential-epitenon sutures caused worsening of TAROM after 2 years. No conclusions can be drawn regarding reoperation rates among the groups. Level of evidence: Therapeutic level I.

Fractured morphology of femoral head associated with subsequent femoral neck fracture: Injury analyses of 2D and 3D models of femoral head fractures with computed tomography.

Background: The injury of femoral head varies among femoral head fractures (FHFs). In addition, the injury degree of the femoral head is a significant predictor of femoral neck fracture (FNF) incidence in patients with FHFs. However, the exact measurement methods have yet been clearly defined based on injury models of FHFs. This study aimed to design a new measurement for the injury degree of the femoral head on 2D and 3D models with computed tomography (CT) images and investigate its association with FHFs with FNF. Methods: A consecutive series of 209 patients with FHFs was assessed regarding patient characteristics, CT images, and rate of FNF. New parameters for injury degree of femoral head, including percentage of maximum defect length (PMDL) in the 2D CT model and percentage of fracture area (PFA) in the 3D CT-reconstruction model, were respectively measured. Four 2D parameters included PMDLs in the coronal, cross-sectional and sagittal plane and average PMDL across all three planes. Reliability tests for all parameters were evaluated in 100 randomly selected patients. The PMDL with better reliability and areas under curves (AUCs) was finally defined as the 2D parameter. Factors associated with FNF were determined by binary logistic regression analysis. The sensitivity, specificity, likelihood ratios, and positive and negative predictive values for different cut-off values of the 2D and 3D parameters were employed to test the diagnostic accuracy for FNF prediction. Results: Intra- and inter-class coefficients for all parameters were ≥0.887. AUCs of all parameters ranged from 0.719 to 0.929 (p < 0.05). The average PMDL across all three planes was defined as the 2D parameter. The results of logistic regression analysis showed that average PMDL across all three planes and PFA were the significant predictors of FNF (p < 0.05). The cutoff values of the average PMDL across all three planes and PFA were 91.65% and 29.68%. The sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, predictive positive value and negative predictive value of 2D (3D) parameters were 91.7% (83.3%), 93.4% (58.4%), 13.8 (2.0), 0.09 (0.29), 45.83% (10.87%), and 99.46% (98.29%). Conclusion: The new measurement on 2D and 3D injury models with CT has been established to assess the fracture risk of femoral neck in patients with FHFs in the clinic practice. 2D and 3D parameters in FHFs were a feasible adjunctive diagnostic tool in identifying FNFs. In addition, this finding might also provide a theoretic basis for the investigation of the convenient digital-model in complex injury analysis.

Radiologists with assistance of deep learning can achieve overall accuracy of benign-malignant differentiation of musculoskeletal tumors comparable with that of pre-surgical biopsies in the literature.

PURPOSE: The purpose of this study was to assess if radiologists assisted by deep learning (DL) algorithms can achieve diagnostic accuracy comparable to that of pre-surgical biopsies in benign-malignant differentiation of musculoskeletal tumors (MST). METHODS: We first conducted a systematic review of literature to get the respective overall diagnostic accuracies of fine-needle aspiration biopsy (FNAB) and core needle biopsy (CNB) in differentiating between benign and malignant MST, by synthesizing data from the articles meeting our inclusion criteria. To compared against the accuracies reported in literature, we then invited 4 radiologists, respectively with 2 (A), 6 (B), 7 (C), and 33 (D) years of experience in interpreting musculoskeletal MRI to perform diagnostic tests on our own dataset (n = 62), with and without assistance of a previously developed DL algorithm. The gold standard for benign-malignant differentiation was histopathologic confirmation or clinical/radiographic follow-up. RESULTS: For FNAB, a meta-analysis containing 4604 samples met the inclusion criteria, with the overall diagnostic accuracy reported to be 0.77. For CNB, an overall accuracy of 0.86 was derived by synthesizing results from 7 original research articles containing a total of 587 samples. On our internal MST dataset, the invited radiologists, respectively, achieved diagnostic accuracies of 0.84 (A), 0.89 (B), 0.87 (C), and 0.90 (D), with the assistance of DL. CONCLUSION: Use of DL algorithms on musculoskeletal dynamic contrast-enhanced MRI improved the benign-malignant differentiation accuracy of radiologists to a level comparable to that of pre-surgical biopsies. The developed DL algorithms have a potential to lower the risk of miss-diagnosing malignancy in radiological practice.

Finite element analysis of necessity of reduction and selection of internal fixation for valgus-impacted femoral neck fracture.

This study compared the biomechanical characteristics of different treatment strategies based on finite element analysis. Posterior tilt and valgus angle were measured on X-ray from ten valgus-impacted femoral neck fractures, and 7 finite element models that were generated to compare the stress and displacement. The results showed that in the intact femur, von Mises stress was concentrated at the medial and inferior sides of the femoral neck. In valgus-impacted femoral neck fractures, von Mises stress was at the same locations but was 5.66 times higher than that in the intact femur. When 3 cannulated screws were used for internal fixation, anatomic reduction diminished the stress at the fracture end from 140.6 to 59.14 MPa, although displacement increased from 0.228 to 0.450 mm. When the fracture was fixed with a sliding hip screw (SHS) + cannulated screw, there was less stress at the fracture end and greater displacement with anatomic reduction than that without reduction (stress: 15.9 vs 37.9 MPa; displacement: 0.329 vs 0.168 mm). Therefore, the SHS + cannulated screw has superior biomechanical stability than 3 cannulated screws, and is recommended following anatomic reduction to treat valgus-compacted femoral neck fractures.

Reoperation rate and implants' position variation features of displaced femoral neck fractures with sliding compression or length-stable fixation in young and middle-aged population.

INTRODUCTION: Sliding compression fixation and length-stable fixation are two basic internal fixation concepts in the treatment of displaced femoral neck fractures. In this study, we aimed to compare the reoperation rates for different methodologies of internal fixation for femoral neck fractures in young and middle-aged population. MATERIALS AND METHODS: This a retrospective study. A total of 215 patients with displaced femoral neck fractures treated with cannulated screw fixation were enrolled and divided into the sliding compression and length-stable groups according to the fixation pattern. The occurrence of and reason for revision surgery within one year were recorded. Forty-five patients with complete CT data (including CT scanning on the first postoperative day and at the last follow up) were selected from the total sample. A newly established computerized image processing method was used to evaluate variations in the spatial location of screws. RESULTS: The reoperation rate was significantly higher in the length-stable group (23.8%) than in the sliding compression group (7.3%). The rate of revision surgery due to nonunion was also higher in the length-stable group (11.4%) than in the sliding compression group (1.8%). However, no significant difference was observed in terms of joint penetration or soft tissue irritation. The sliding compression group (6.58 ± 3.18 mm) showed higher femoral neck shortening than length-stable group (4.16 ± 3.65 mm). When analyzing the spatial variations, a significantly greater screw withdrawal distance was observed in the sliding compression group than in the length-stable group, but with a smaller rotation angle. CONCLUSION: Length-stable internal fixation of displaced femoral neck fractures may lead to an increased reoperation rate in young and middle-aged population. TRIAL REGISTRATION: Name of the registry: Chinese Clinical Trial Registry. TRIAL REGISTRATION NUMBER: ChiCTR2000032327. Trial registration date: 2020-4-26.

Three-dimensional computed tomography mapping and clinical predictive factors for morphologic characterization of displaced femoral neck fractures.

Background: This study aimed to define the distribution and frequency of fracture lines and bone defects in displaced femoral neck fractures (DFNFs) using a three-dimensional (3D) mapping technique, and to investigate the factors associated with the area of bone defects in patients with DFNFs. Methods: The data of 256 adult patients with DFNFs were retrospectively reviewed. Multiplanar reconstructions of the DFNFs were made using computed tomography (CT) images, and the DFNF fragments were virtually reduced to match a 3D model of the femoral neck. Subsequently, 3D mapping was performed by graphically superimposing all of the fracture lines and bone defects onto a femoral neck template. The 3D mappings were independently examined by two orthopedic surgeons, and the interobserver agreement was analyzed. For intraobserver analysis, one of the surgeons measured the mappings twice more, and the intraclass correlation coefficients (ICCs) were calculated. A linear regression analysis was conducted to explore bone defect area-related factors. Results: The cohort comprised 141 (55%) patients with left hip injuries and 115 (45%) patients with right hip injuries. On the 3D maps, the dense zones of the fracture lines were largely observed from the superior to the posterior part of the femoral neck, while the dense zone of the bone defect was primarily concentrated in the posterior part of the femoral neck. Only a few dense zones were located in the anterior and inferior parts of the femoral neck. An overlapping region between the fracture line and the bone defect was located in the 2.5th to 4.5th (5th) part of the 1/10 of the superior (posterior) femoral neck length. Both the fracture line and bone defect mapping techniques had good intra- and inter-observer reliability, with ICCs of 0.879 (0.977) and 0.780 (0.974), respectively. Garden type and age were positively correlated with bone defects, while simplified AO Foundation/Orthopaedic Trauma Association (AO/OTA) classification was negatively associated with bone defects. Conclusions: The fracture lines and bone defects of the DFNFs were mainly located in the superior and posterior parts of the femoral neck, while an overlapping region was observed in the subcapital area of the femoral neck. 3D mapping is a reliable method for searching for DFNF features, and separately studying fracture lines and bone defects can further elucidate the morphology of these fractures. Bone defects in patients with DFNFs were associated with Garden type, simplified AO/OTA classification, and age.

Fracture line distribution in femoral head fractures: a complement to Pipkin, Brumback, and AO/OTA classifications.

PURPOSE: This study aimed to explore the fracture line distribution and validate fracture classifications of Femoral head fractures (FHFs). MATERIALS AND METHODS: A total of 209 FHFs were reviewed retrospectively. Subjects were classified by associated injuries and commonly used fracture classifications (Pipkin, Brumback, and AO/OTA), and the universality degree of classifications was evaluated. The fracture line directions were determined in the coronal and axial CT planes. 3D mapping analysis of fracture lines was performed separately by each group. 3D maps were employed to analyze the discrimination degree of inter-subtype classifications and create a new classification. The subjects were subsequently reclassified. Correlations between classifications were analyzed to determine the matching degree of the three classifications. RESULTS: The universality degrees were 98.6% (pipkin), 44.5% (Brumback), and 94.3% (AO/OTA). The cases of (100%) Brumback and (98.5%) AO/OTA can be classified by Pipkin. The mean angles of fracture lines to the coronal and axial axis of primary compressive trabeculae were 20.25° and 54.56°. The discrimination degrees of inter-subtype of classifications were 0 (Pipkin), 60% (Brumback), and 33% (AO/OTA). A new classification with three regions and five types was created on 3D maps. Pipkin and AO/OTA matched one region, while Brumback matched two regions. CONCLUSIONS: There were three distributed fracture regions in FHFs that mismatched Pipkin, Brumback, and AO/OTA classifications. The new classification, based on morphometric features of FHFs, could compensate for the shortcomings of commonly used classifications, improving their applicability in treating FHFs.

3D Mapping of Bone Channel of Blood Supply to Femoral Head in Proximal Femur.

Background: A detailed depiction of nutrient foramina is useful for defining guidelines and minimising iatrogenic damage during hip surgery. Therefore, this study aimed to define the location and frequency of nutrient foramina in the proximal femur using mapping techniques. Methods: One hundred dry human cadaveric proximal femurs, comprising 56 left and 44 right femurs, were scanned using a three-dimensional scanner, with scanning distance 200 mm, precision 0.01 mm, and measuring point 0.04 mm. The image resolution of 1,310,000 pixels was obtained. Digital imaging models were acquired from the proximal femur surface. All the nutrient foramina in each model were identified and marked. The nutrient foramina models were superimposed on one another and oriented to fit a standard template of the femur's proximal aspect. Three-dimensional mapping in the proximal femur's nutrient foramina was performed. Results: The nutrient foramina's location and dense zones were identified. The dense zones were distributed along the vascular course and gaps between the muscle attachment sites. Eighteen dense zones were identified and found to be location-dependent. They were located in the central part of the fovea capitis femoris, subcapital and basicervical areas of the femoral neck, and muscle attachment gaps of the femoral trochanter. Conclusions: The terminal branch of the nutrient vessels entering the nutrient foramina is at risk for iatrogenic damage during hip surgeries, especially in cases of close bone exposures. There are 18 dense zones that need to be considered for a safer approach to the proximal femur. To minimise iatrogenic damage to the nutrient vessels entering the nutrient foramina, the dense areas should be avoided when technically possible.

Association between Weitbrecht's Retinaculum Injury and Femoral Head Necrosis in Femoral Neck Fractures.

OBJECTIVE: To investigate associations between femoral head necrosis (FHN) and injury to the retinaculum of Weitbrecht in patients with femoral neck fractures who had undergone initial trials of either closed reduction or direct open reduction. METHODS: This prospective observational study included 110 patients with displaced femoral neck fractures admitted to the Sixth People's Hospital Affiliated to Shanghai Jiaotong University and Shanghai Tongji Hospital between January 2008 and May 2017. Among these, 25 patients underwent initial closed reductions, and 85 patients underwent an open reduction directly. Watson-Jones anterolateral approach was used during the surgery for injury to the retinaculum of Weitbrecht, and FHN was assessed as a surgical outcome. The severity of injury to the retinaculum of Weitbrecht was evaluated using a scoring system developed by our surgical team. Follow-up was at least 24 months. RESULTS: The initial closed reduction treatment group had significantly higher total scores of injury to the retinaculum of Weitbrecht (6.24 ± 2.20 vs 4.62 ± 2.12, p = 0.009) compared to the open reduction group. High total scores were significantly associated with initial trials of closed reduction treatment, especially for the broken and released injury to the superior and anterior retinacula (both p = 0.01). Twenty-six patients experienced FHN postoperatively, with mean onset time of 19.42 ± 3.87 months. FHN was significantly associated with the severity of injury to the retinaculum of Weitbrecht (p < 0.001) at the superior, anterior, and inferior retinacula. FHN was significantly associated with injury to the retinaculum of Weitbrecht in females. CONCLUSIONS: Femoral neck displacement in patients treated initially with closed reduction is associated with subsequent injury to the retinaculum of Weibrecht, which may lead to FHN. Severity of injury to the retinaculum of Weibrecht may be used as a biomarker to evaluate bone necrosis in patients with femoral neck fractures.