Intracapsular fracture of the femoral neck remains one of the most challenging injuries in orthopaedic trauma because of its inconsistent healing potential and the high risk of avascular necrosis (AVN) of the femoral head. These fractures account for a significant proportion of hip injuries globally, with an incidence estimated at 0.63/1000 women and 0.27/1000 men annually [1]. The complexity arises primarily from the unique vascular anatomy of the femoral head, which is susceptible to disruption even with minimally displaced fractures. Displacement of the femoral neck fragment compromises the retinacular vessels, increases intracapsular tamponade pressure, and interrupts the nutrient circulation, substantially increasing the risk of osteonecrosis[2,3]. In addition, delayed surgical intervention further aggravates the vascular insult, cumulatively contributing to reported AVN rates of 10–30% and non-union rates as high as 20–35% in displaced injuries [4,5]. The treatment paradigm for intracapsular fractures differs significantly between younger and older patients. In patients below 60 years of age, preservation of the femoral head through anatomical reduction and stable internal fixation remains the preferred goal because of the long-term functional implications of arthroplasty [6]. However, the prognosis following fixation largely depends on the residual vascularity of the femoral head at the time of surgery. Identifying this vascular status pre-operatively can aid in selecting candidates who are most likely to benefit from head-preserving surgery. Historically, several modalities—including radionuclide scanning, digital subtraction angiography, and unenhanced MRI—have been attempted for early evaluation of femoral head perfusion, but each has significant limitations, particularly during the first 48 hours following injury [7,8]. Dynamic contrast-enhanced MRI (DMRI) has emerged as the most sensitive and reliable non-invasive modality for early assessment of femoral head perfusion. It allows quantification of signal-intensity enhancement curves that reflect the perfusion status of the femoral head relative to the contralateral side. Studies by Konishiike et al. and Hirata et al. have demonstrated high predictive accuracy of DMRI in forecasting osteonecrosis and non-union, with absent enhancement (Type C curve) strongly correlating with poor outcomes [9,10]. When applied at early presentation, DMRI not only facilitates risk stratification but also supports surgical decision-making, especially in borderline age groups where the choice between fixation and replacement remains controversial. The present work—derived from the thesis “Outcome of Treatment of Intracapsular Neck Femur Based on Pre-operative Vascular Assessment of Femoral Head by Dynamic MRI”—aims to evaluate the predictive value of DMRI in determining treatment outcomes following internal fixation of intracapsular femoral neck fractures. It further investigates the correlation between dynamic curve patterns and radiological outcomes such as union, non-union, and AVN. By integrating vascular assessment into the treatment pathway, this study seeks to enhance individualized decision-making and optimize functional outcomes.

This prospective observational study was conducted in the Department of Orthopaedics, Pt. J.N.M. Medical College and Dr. B.R. Ambedkar Memorial Hospital, Raipur, between January 2014 and March 2015. A total of 18 patients with traumatic intracapsular neck femur fractures meeting the inclusion criteria were initially enrolled. After excluding one patient who required primary replacement and another lost to follow-up, 16 patients constituted the final study cohort. Clinical and radiographic assessments were performed at presentation, and all observations were recorded as per the institutional proforma. Standard anteroposterior and lateral radiographs of the affected hip were obtained, including a 15° internal rotation AP view to improve visualization of the femoral neck. Fractures were classified based on Garden’s criteria into displaced (Types III–IV) and undisplaced (Types I–II). All eligible patients underwent dynamic contrast-enhanced MRI as early as feasible following hospital admission. MRI acquisition was performed on a SIGNA 3.0 Tesla GE superconducting system. T1-weighted fast spin-echo sequences were acquired in axial and coronal planes. A paramagnetic contrast agent—gadolinium-DTPA at 0.1 mmol/kg—was injected intravenously, and sequential images were captured at 7-second intervals to generate perfusion-time curves. Regions of interest (ROIs) were placed over the femoral head and greater trochanter bilaterally. Dynamic enhancement curves were classified into three perfusion types: Type A (normal perfusion, within 25–30% of contralateral side), Type B (reduced perfusion, 30–70%), and Type C (markedly impaired perfusion, >70% reduction). This classification followed previously published DMRI methodologies [9,10]. Surgical treatment was planned according to patient age, fracture displacement, and DMRI findings. Patients in borderline age groups exhibiting Type C perfusion were counselled regarding a higher likelihood of fixation failure and AVN. Internal fixation was performed using either multiple 6.5-mm partially threaded cancellous screws or dynamic hip screw (DHS) device as per standard surgical principles. Reduction quality was assessed intraoperatively based on Garden’s alignment index. Postoperative follow-up occurred at 3, 6, and 12 months. Radiological outcomes—including union, non-union, avascular necrosis, and fixation failure—were documented. Statistical analysis employed Chi-square testing to evaluate associations between DMRI perfusion types and treatment outcomes.

A total of 16 patients with intracapsular femoral neck fractures were evaluated clinically and radiographically. Patients ranged from 16 to 65 years of age, with a predominance of males and high-energy trauma. Dynamic contrast-enhanced MRI was successfully performed in all patients, and perfusion curves (Type A, B, and C) were generated to assess the residual vascularity of the femoral head. Radiological outcomes were documented up to 12 months, focusing on fracture union, non-union, and their relationship with DMRI curve type. 1. Demographic Characteristics Narrative Findings Most patients (50%) were between 36–55 years of age, representing the active working population. A significant male predominance (87.5%) reflects gender-linked exposure to high-energy trauma, especially road-traffic injuries. Table 1. Age and Sex Distribution Variable Category n % Age (years) 16–25 4 25 26–35 3 18.7 36–45 4 25 46–55 4 25 56–65 1 6.3 Sex Male 14 87.5 Female 2 12.5 2. Fracture Characteristics Narrative Findings Subcapital and transcervical fractures were evenly distributed. Displacement was present in 50% of cases. These characteristics are important as displaced fractures are known to have higher risk of vascular compromise and subsequent non-union. Table 2. Type and Pattern of Fracture Variable Category n % Fracture Type Subcapital 8 50 Transcervical 8 50 Displacement Undisplaced (Garden I–II) 8 50 Displaced (Garden III–IV) 8 50 3. Dynamic MRI Perfusion Pattern Narrative Findings DMRI revealed Type A perfusion in 43.75%, indicating preserved vascularity. Type B (31.25%) reflected reduced but present perfusion, whereas Type C (25%) indicated severe vascular compromise. This distribution highlights that a significant subset of patients have compromised head perfusion at presentation. Table 3. DMRI Perfusion Curve Types DMRI Curve Interpretation n % Type A Normal perfusion 7 43.75 Type B Reduced perfusion 5 31.25 Type C Markedly reduced / absent perfusion 4 25 4. Correlation Between DMRI Pattern and Union Narrative Findings A clear correlation was observed between perfusion type and healing. • All Type A fractures achieved union (100%), showing that preserved perfusion strongly predicts successful osteosynthesis. • Type B had a mixed outcome, with 60% union. • Type C had the poorest outcomes, with 75% non-union. This confirms that DMRI is a powerful predictor of biological healing potential. Table 4. DMRI Perfusion Pattern vs Union Outcome DMRI Type n Union Non-union Type A 7 7 0 Type B 5 3 2 Type C 4 1 3 5. Correlation Between DMRI Pattern and Fracture Displacement Narrative Findings Perfusion impairment increased with displacement: • 71% of Type A curves belonged to undisplaced fractures • 75% of Type C curves belonged to displaced fractures This supports the known pathophysiology that displaced fractures significantly compromise femoral head blood supply. Table 5. DMRI Curve Type vs Fracture Displacement DMRI Type Undisplaced Displaced Type A 5 2 Type B 2 3 Type C 1 3 6. Overall Treatment Outcome Narrative Findings Of the 16 patients, 11 achieved union (68.75%) and 5 developed non-union (31.25%). Non-union was strongly associated with displaced fractures and Type C perfusion curves, confirming that pre-operative vascularity assessment is clinically valuable. Table 6. Overall Union Rates Fracture Type n Union Non-union Undisplaced (n=8) 8 6 (75%) 2 (25%) Displaced (n=8) 8 5 (62.5%) 3 (37.5%)

The present study demonstrates a clear and clinically meaningful correlation between pre-operative femoral head vascularity assessed through Dynamic MRI (DMRI) and the eventual outcome of osteosynthesis in intracapsular neck femur fractures. The stratification of perfusion patterns into Type A, B, and C curves allowed early identification of patients at higher risk of non-union, particularly those exhibiting markedly reduced enhancement. These findings are consistent with the foundational anatomical work of Judet et al. [11], who highlighted the vulnerability of the retinacular vessels to displacement, and with the observations of Kregor [12], who demonstrated that vascular injury from the fracture itself plays a dominant role in determining prognosis. In the current study, all Type A cases united (100%), affirming that preserved perfusion supports biological healing. A similar relationship was reported by Meyers et al. [13], who showed that early perfusion assessment helps predict femoral head viability. The partial perfusion category (Type B) demonstrated mixed outcomes, aligning with the scintigraphic variability documented by Philipps et al. [14]. In contrast, Type C curves showed a 75% non-union rate, mirroring the high failure rates reported by Turner [15] using Tc-99m colloid and by Lucie et al. [16], who demonstrated that severe early hypoperfusion strongly predicts avascular necrosis (AVN) and non-union. The study also confirms the established relationship between fracture displacement and vascular compromise. A majority of displaced fractures were associated with Type C perfusion, supporting the angiographic findings of Theron [17], who showed interruption of the superior nutrient vessels in displaced fractures. Additionally, the DMRI-based perfusion deficit observed in our displaced fractures is consistent with the reduced intra-osseous oxygen tension measurements reported by Kiaer et al. [18], further emphasizing the physiological basis of perfusion-outcome correlation. Dynamic MRI offers distinct advantages over other modalities historically used for evaluating femoral head perfusion. While radionuclide scanning, as described by D’Ambrosia et al. [19], provides early functional information, it lacks the anatomical resolution and side-to-side comparison achievable with DMRI. Similarly, unenhanced MRI, although valuable for detecting established AVN, is unable to reliably assess perfusion within the first 48 hours. In contrast, dynamic contrast-enhanced imaging, as established by Konishiike and Hirata [20], provides quantifiable enhancement curves that closely predict healing potential and complications. In summary, the present study reinforces DMRI as a reliable, non-invasive, and clinically actionable tool in the management of femoral neck fractures. Identifying perfusion deficits pre-operatively is particularly valuable in borderline age groups where the choice between fixation and arthroplasty requires individualized planning. The findings not only validate earlier research but also support integrating DMRI into treatment algorithms to optimize outcomes.

This study demonstrates that Dynamic MRI is a highly reliable method for assessing pre-operative femoral head vascularity in patients with intracapsular femoral neck fractures. The perfusion patterns obtained—Type A, B, and C—strongly correlated with final radiological outcomes, with Type A showing complete union, Type B yielding variable results, and Type C associated with significantly higher non-union rates. The findings confirm that vascular compromise is a key determinant of biological healing potential and that displacement markedly increases the likelihood of perfusion loss. By identifying patients at high risk for non-union or avascular necrosis, DMRI enables more accurate treatment planning, particularly in younger and borderline-age individuals where head preservation is preferred. Integrating DMRI into routine evaluation protocols can enhance clinical decision-making, reduce unnecessary surgical failures, and facilitate individualized patient management. Overall, DMRI offers a robust, non-invasive tool for predicting prognosis and guiding optimal treatment strategies.

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