Incidence and Risk Factors for Femoral Malrotation Following Intramedullary Nailing of Trochanteric Fractures: A CT-Based Analysis

Abstract

Objective

To quantify rotational displacement following intramedullary nail fixation for intertrochanteric femoral fractures using three-dimensional (3D) CT imaging, analyze associated risk factors, and evaluate its clinical significance.

Methods

This study enrolled a cohort of 252 patients who underwent intramedullary nail fixation for intertrochanteric femoral fractures between 2019 and 2023. All participants underwent postoperative three-dimensional computed tomography (3D CT) and were followed for a minimum of 1 year. Postoperative femoral anteversion on the affected side was quantitatively assessed. An analysis was conducted to evaluate its correlation with potential risk factors, including age, sex, body mass index (BMI), American Society of Anesthesiologists (ASA) classification, nail length, type of internal fixation, reduction quality, AO Foundation/Orthopaedic Trauma Association (AO/OTA) fracture classification, presence of medial cortical defect, bone mineral density (T-score), Singh’s index, relative lateral wall thickness (rLWT), tip-apex distance (TAD), neck-shaft angle, and fracture classification. The impact of differences in anteversion on long-term clinical outcomes, including Visual Analog Scale (VAS) pain scores and Harris Hip Scores (HHS), was assessed through follow-up evaluations.

Results

After screening for exclusion criteria, a total of 210 patients were enrolled in the study: 33 patients (15.7%) exhibited differences in anteversion exceeding 15°; 177 patients (84.3%) were under 15°. In the subgroup with version deviations <15°, precise anatomical restoration (anteversion ≤5°) was achieved in 138 cases (77.9%), consistent with optimal biomechanical reconstruction targets; functionally compensated malrotation (5° < anteversion <15°) occurred in 39 patients (22.1%), within the tolerance range for gait adaptation without clinical impairment. Single-nail fixation, medial cortical defects, T-score >2.5, rLWT and fracture classification were identified as the primary factors contributing to rotational displacement exceeding 15°. At the 1-year follow-up, patients with smaller rotational displacement demonstrated better functional recovery, as reflected by improved Visual Analog Scale (VAS) pain scores and Harris Hip Scores (HHS).

The multivariate linear regression analysis demonstrated that the rLWT showed significant correlation with rotational displacement of fracture fragments after intramedullary nail fixation.

Conclusion

Bone rotation and displacement are frequently observed following intramedullary nail fixation for intertrochanteric fractures. The rLWT is closely associated with these complications. Therefore, meticulous attention to surgical technique is essential to minimize complications and optimize outcomes.

Keywords

intertrochanteric fracture of femur fracture reduction difference in anteversion fracture rotation internal fixation with intramedullary nail

Introduction

Hip fractures among elderly individuals, commonly associated with high mortality rates and severe health outcomes, constitute a critical public health challenge affecting populations worldwide. According to the United Kingdom’s National Hip Fracture Database (NHFD), the incidence of hip fractures has risen markedly over the past few decades, with an annual average of 70 000 to 80 000 cases reported.¹ Hip fractures are clinically classified into two principal subtypes - femoral neck fractures and intertrochanteric fractures. Standard therapeutic protocols typically involve traction-assisted closed reduction followed by definitive internal fixation via either dynamic hip screw systems or intramedullary nailing devices, with implant selection guided by fracture morphology and patient-specific biomechanical factors.² The quality of fracture reduction is a critical determinant of patient prognosis.³

Intraoperative evaluation of reduction adequacy in intertrochanteric fracture repair predominantly relies on biplanar fluoroscopic imaging. Nevertheless, accurate identification of rotational malreduction persists as a persistent clinical challenge, attributable to the inherent limitations of conventional radiography-specifically, restricted spatial resolution and the loss of three-dimensional anatomical information inherent to two-dimensional projection techniques. Emerging evidence suggests that adjunctive intraoperative modalities, such as computed tomography (CT)-augmented navigation or dynamic stress fluoroscopy, may enhance rotational alignment assessment, though current accessibility constraints limit routine clinical implementation.⁴ Consequently, research in this area has been limited. Recent studies by Ramanoudjame⁵ and Kim et al.⁶ utilized three-dimensional (3D) CT scans to evaluate postoperative differences in femoral anteversion. Their findings revealed that 25% to 40% of patients exhibited significant differences in anteversion postoperatively, with most cases demonstrating an increase in anteversion, defined as a difference exceeding 15° compared to the healthy side. Further analysis by Karaman et al.⁷ highlighted the relationship between rotational displacement of fracture fragments and functions of the femoral shaft, emphasizing that the femoral rotational malalignment of ≥10° is symptomatic for the patients, and the hip, knee, and patellofemoral joints were affected. Because of the possibly altered joint loadings and biomechanics, these could render patients prone to degenerative joint disease. Achieving optimal mechanical stability is crucial for fracture healing, as it reduces complications such as screw cut-out or nail breakage and facilitates early weight-bearing activities.

As a major weight-bearing joint, the hip’s biomechanical integrity is critically dependent on physiological limb alignment. Deviations from the normal mechanical axis induce pathological joint loading patterns, which may progressively compromise ambulatory function through gait disturbance and compensatory mechanisms.⁸ Consequently, meticulous attention to rotational malreduction is imperative in intertrochanteric fracture management. Although rotational displacement is not uncommon in the treatment of intertrochanteric fractures, there is a paucity of research on its impact on functional outcomes and associated risk factors. In this study, we retrospectively analyzed clinical data from patients with unstable intertrochanteric fractures treated with intramedullary nailing at our institution. Our aim was to investigate the patterns and extent of rotational displacement, identify related risk factors, and provide insights to guide clinical practice.

Material and Methods

Study Design

This retrospective cohort study was conducted in accordance with the STROBE guidelines⁹ and adhered to the principles of the Declaration of Helsinki (2013 revision). The study protocol was approved by the Ethics Committee of Tianjin Hospital (Approval No. 202235). We retrospectively analyzed patients who underwent intramedullary nailing for intertrochanteric femoral fractures at Tianjin Hospital between November 2019 and August 2023.

Inclusion and Exclusion Criteria

Patients who underwent closed reduction and intramedullary nailing for intertrochanteric fractures at the Department of Hip Traumatology, Division II, Tianjin University Tianjin Hospital, China, between 2019 and 2023 were included. Postoperative X-rays and 3D CT scans of the hip joints were routinely performed. The inclusion and exclusion criteria were as follows:

Inclusion Criteria

Patients were eligible for the study if they met the following conditions: age 65 years or older; diagnosis of an isolated intertrochanteric fracture treated with closed reduction and intramedullary nailing; ability to ambulate independently with full weight-bearing capacity prior to the fracture; absence of uncontrolled medical comorbidities; and availability of complete preoperative and postoperative imaging data.

Exclusion Criteria

Patients were excluded from the study if they exhibited any of the following: pathological fractures (eg, those secondary to malignancy or metabolic bone disease); severe uncontrolled medical comorbidities (eg, advanced cardiac, pulmonary, or renal disease) or concurrent multiple traumatic fractures; prior surgical interventions involving the hip or femur; or bilateral hip fractures or ipsilateral femoral neck fractures, including concomitant injuries identified during preoperative imaging.

Anesthesia, Reduction, and Internal Fixation

All patients were positioned supine under general or epidural anesthesia. Closed reduction was performed using a traction table under C-arm guidance. The reduction technique involved full traction of the affected limb, followed by adduction and internal rotation to the neutral position. For fractures that could not be reduced by traction alone, minimally invasive reduction techniques described by Kim et al.¹⁰ and Aktselis et al.¹¹ were employed.

The following intramedullary nail systems were utilized in the surgical procedures: the Stryker Gamma3 U-Blade; the AO modified proximal femoral anti-rotation nail (PFNA); the Smith & Nephew InterTAN; and the Stryker Gamma3 (standard configuration).

Postoperative Management

From the second postoperative day, patients were encouraged to sit up in bed and initiate lower limb muscle strengthening exercises. By the third postoperative day, patients were permitted to sit on the bedside and perform knee flexion and extension exercises, provided there was no evidence of deep vein thrombosis. Six weeks postoperatively, based on fracture healing progress, patients were advised to begin partial weight-bearing with the assistance of double crutches, gradually progressing to full weight-bearing as tolerated.

Perioperative Imaging Evaluation of Fracture Rotation and Internal Fixation Quality

Perioperative imaging, including X-rays and 3D CT scans of the affected hip, was performed to evaluate the rotational displacement of the fracture and assess the quality of internal fixation placement. Femoral anteversion was calculated using multiplanar reconstructed CT images in our institutional PACS system. The methodology followed Kim et al⁶: The anteversion angle between the axis of the fractured femoral neck and the posterior axis of the distal femoral condyles was automatically calculated using the PACS angle measurement tool, thereby eliminating potential errors associated with manual protractor-based measurements. Printed radiographic films were reserved exclusively for secondary verification by two independent orthopedic surgeons, with inter-observer variance maintained below 1°. Inter-rater reliability analysis demonstrated substantial agreement (κ = 0.82), and no statistically significant differences were observed between the assessments of the two physicians. (Figure 1).

Figure 1.

A 67-Year-old Female Patient With a Left Femoral Intertrochanteric Fracture (AO/OTA Type 31-A2.2). A1: Preoperative Anteroposterior (AP) Radiograph; A2: Preoperative Lateral Radiograph; B1-B2: Postoperative AP and Lateral Radiographs after Surgery; C1: Measurement of Anteversion in the Affected Limb Following Internal Fixation; C2: Measurement of Anteversion in the Healthy Contralateral Limb

Tip-Apex Distance (TAD) Assessment

The position of the lag screw within the femoral head was evaluated according to the criteria established by Baumgaertner et al.¹² TAD <25 mm was confirmed as biomechanically sufficient for minimizing cut-out risk.

Quality of Internal Fixation

The stability of internal fixation was evaluated by assessing the anteromedial cortical defect of the fracture using 3D CT imaging.¹³

Fracture Reduction Quality Assessment

The relationship between the proximal bone fragment and the femoral shaft was assessed based on the criteria proposed by Mao et al.¹⁴ (Figure 2) and the quality of fracture reduction was assessed as follows:

Figure 2.

Fig. A-C: neutral Medial Position, Positive Medial Cortical Support, and Negative Medial Cortical Support. Fig. D-E: neutral Anterior Position, Positive Anterior Cortical Support, and Negative Anterior Cortical Support. The Quality of Fracture Reduction was Evaluated as follows:Excellent: Positive or Neutral Support Observed in Both AP and Lateral Radiographs. Good: Negative Support in Either AP or Lateral Radiographs, With Positive or Neutral Support in the Other view. Poor: Negative Support in Both AP and Lateral Radiographs

Excellent: Positive or neutral support observed in both AP and lateral radiographs.

Good: Negative support in either AP or lateral radiographs, with positive or neutral support in the other view.

Poor: Negative support in both AP and lateral radiographs.

Fracture Characterization and Osteoporosis Assessment

Relative Lateral Wall Thickness Measurement

On standardized anteroposterior (AP) hip radiographs, the relative lateral wall thickness (rLWT) was quantified to establish patient-specific anatomical baselines.¹⁵ This pre-fracture measurement reflects intrinsic femoral geometry, thereby enabling individualized surgical planning independent of subsequent lateral wall integrity status.

Osteoporosis T-Score

The T-score of all patients was recorded. A T-score of −2.5 or lower was defined as osteoporosis.

Follow-Up and Efficacy Evaluation

Patients were scheduled for outpatient follow-up 1 year after discharge. Clinical outcomes were assessed using the Visual Analog Scale (VAS) for pain and the Harris Hip Score (HHS),¹⁶ which are widely recognized tools for evaluating pain and functional outcomes in elderly patients with hip fractures.

Outcome Measures

Primary Outcome is the rotational instability, defined as postoperative femoral anteversion difference ≥15° compared to the contralateral side, measured via 3D CT.

Secondary Outcomes includes: functional outcomes (such as HHS, VAS), implant-related complications, radiographic parameters, and osteoporosis-related indicators.

Statistical Analysis

Statistical analysis was performed using SPSS 25.0 software. Normally distributed continuous data were expressed as mean ± standard deviation (Mean ± SD), while non-normally distributed data were presented as median (interquartile range, IQR) [M (P25, P75)]. Univariate analysis was conducted using the student’s t-test or Mann-Whitney U test, as appropriate. Categorical variables were analyzed using the chi-square test or Fisher’s exact test, depending on the sample size and clinical relevance. All hypothesis tests were two-tailed. Variables with a P-value ≤0.05 in univariate analysis were included in multivariate analysis using a linear regression model. A P-value ≤0.05 was considered statistically significant.

Results

General Results

After screening exclusion criteria, a total of 210 patients with a mean age of 73.2 years (range: 65 - 90 years) were enrolled in the study. (Figure 3) Among them, 119 were female and 91 were male. The most common injury mechanism was a fall from a standing height. All patients underwent closed reduction and intramedullary nail fixation under C-arm fluoroscopy guidance. The operative duration ranged from 45 to 100 minutes, with a mean duration of 62 ± 23.8 minutes.

Figure 3.

Flowchart of Patient Selection

Characteristics of Differences in Anteversion

Quality of Fracture Reduction

Among all patients, 120 cases (57.1%) were classified as excellent, 83 cases (39.5%) as good, and 7 cases (3.4%) as poor.

Fracture Fragment Rotation Groupings and Correlation with Risk Factors

Malrotation threshold was set to ≥15° based on published data.⁵ 33 patients (15.7%) exhibited differences in anteversion exceeding 15°; 177 patients (84.3%) were under 15°. In the subgroup with version deviations <15°, precise anatomical restoration (anteversion ≤5°) was achieved in 138 cases (77.9%), consistent with optimal biomechanical reconstruction targets; functionally compensated malrotation (5° < anteversion <15°) occurred in 39 patients (22.1%), within the tolerance range for gait adaptation without clinical impairment.

Risk factors, including age, sex, BMI, ASA classification, Nail length, type of internal fixation, reduction quality, AO classification, medial cortical defect, T-score, Singh’s index, rLWT, tip-apex distance [TAD], Neck-shaft angle and fracture classification, were statistically analyzed (Table 1).

Table 1.

Correlation Analysis of Risk Factors Associated With Rotational Displacement in Fractures.

Values	Total (N = 210)	<15°(N = 177,84.3%)	≥15°(N = 33,15.7%)	P
Age (yr)	73.2 ± 14.9	72.0 ± 11.7	70.8 ± 15.2	0.268
BMI, kg/m²	23.9 ± 4.5	23.3 ± 4.7	24.6 ± 4.1	0.098
ASA classification	2.8 ± 0.6	2.9 ± 0.4	2.8 ± 0.7	0.176
Gender (no. (%))				0.110
Male	91 (43.3)	81 (45.8)	10 (30.3)
Female	119 (56.7)	96 (54.2)	23 (69.7)
Type of lag screw (no. (%))				0.000^*
Single	81 (38.6)	61 (34.5)	20 (60.6)
Non-single	129 (61.4)	116 (65.5)	13 (39.4)
T-score (no. (%))				0.039^*
> −2.5	76 (36.2)	70 (39.5)	6 (18.2)
≤ −2.5	134 (63.8)	107 (60.5)	27 (81.8)
Nail length (no. (%))				0.322
Short	154 (73.3)	132 (74.6)	22 (66.7)
Long	56 (26.7)	45 (25.4)	11 (33.3)
Lateral wall thickness (mm,xˉ±s)	20.76 ± 2.27	22.19 ± 2.66	19.12 ± 2.13	0.000^*
Quality of reduction (no. (%))				0.303
Excellent	120 (57.1)	100 (56.5)	20 (60.6)
Good	83 (39.5)	73 (41.2)	10 (30.3)
Poor	7 (3.4)	4 (2.3)	3 (9.1)
AO classification (no. (%))				0.065
Type A1	40 (19.0)	31 (17.5)	9 (27.3)
Type A2	141 (67.1)	122 (68.9)	19 (57.6)
Type A3	29 (13.9)	24 (13.6)	5 (15.1)
Medial cortical defects				0.009^*
Yes	77 (36.7)	57 (32.2)	20 (60.6)
No	133 (63.3)	120 (67.8)	13 (39.4)
TAD				0.261
≤25 mm	142 (67.6)	113 (63.8)	29 (87.9)
>25 mm	68 (32.4)	64 (36.2)	4 (12.1)
Neck-shaft angle (°)	133 ± 7	129 ± 5	134 ± 8	0.191
Fracture classification				0.003^*
Stable	86	74	12
Unstable	101	89	12
Reverse oblique	23	14	9

Data Presented as Mean ± Standard Deviation or n (%). Independent t-test: Two-tailed, Assuming Equal Variances (Levene’s Test P > 0.1). χ² test: Yates’ Continuity Correction Applied

The results indicated that single-nail fixation, medial cortical defects, T-score >2.5, rLWT and fracture classification were significantly associated with rotational displacement ≥15° compared to the control group (P ≤ 0.05).

Efficacy and Functional Outcomes

All patients completed a minimum 12-month follow-up period (mean duration: 14.8 ± 2.0 months) under supervised functional exercise protocols. Fracture union was achieved in all cases, with healing times ranging from 4 to 9 months (mean: 4.6 ± 1.3 months). No postoperative complications were documented, including wound infection or implant failure. At final follow-up, there were no instances of nonunion, hardware loosening, or revision surgery.

The median VAS score for patients with rotational displacement ≥15° was 2.5 points, compared to 1.6 points in the control group, showing a statistically significant difference (P ≤ 0.05). Similarly, the median HHS for the rotational displacement≥15° group was 76.0 (IQR: 69.0, 85.0), while the control group achieved a median score of 81.3 (IQR: 74.0, 93.0). Patients with smaller rotational displacement angles demonstrated significantly better functional recovery (P ≤ 0.05). (See Table 2 for details.)

Table 2.

Follow-Up Analysis of the Correlation Between Differences in Anteversion and Postoperative Function

Index	<15°	≥15°	Z	P
Harris score	81.3 (74.0,93.0)	76.0 (69.0,85.0)	−48.315	0.00^*
VAS score	1.6 (1,2)	2.5 (2,3)	−11.985	0.00^*

Multivariate Analysis of Fracture Fragment Rotation and Associated Factors

Multivariate linear regression analysis revealed that the rLWT was significantly associated with the degree of fracture fragment rotation following intramedullary nailing (P ≤ 0.05). (See Table 3 for details.)

Table 3.

Multivariate Analysis of Factors Influencing Rotational Displacement Following Intramedullary Nail Fixation for Intertrochanteric Fractures

	B	S.E	Beta	t	Sig	Tolerance	VIF
(Constant)	49.495	6.784		7.296	.000
Type of lag screw	0.122	0.599	0.010	0.203	0.839	0.955	1.047
Medial cortical defects	0.599	0.600	0.050	0.998	0.319	0.930	1.076
T-score	−0.746	0.579	−0.063	−1.289	0.198	0.968	1.033
Fracture classification	0.014	0.458	0.001	0.031	0.976	0.971	1.029
Lateral wall thickness	−2.245	0.316	−0.364	−7.095	0.000	0.874	1.144

Discussion

In the context of intertrochanteric femoral fractures in elderly patients, rotational displacement of fracture fragments following intramedullary nail fixation emerges as a distinct and clinically significant postoperative complication. While rotational displacement is a recognized issue in long - bone fractures, including those of the tibia and femur in general.¹⁷ the specific dynamics and risk factors associated with it in intertrochanteric femoral fractures, particularly in the elderly population, have remained relatively under - explored in the existing literature. In our study, we observed that despite the relatively stable nature of intramedullary nail fixation, rotational displacement still occurred in a subset of elderly patients with intertrochanteric femoral fractures. This finding deviates from the common assumption that intramedullary nailing provides sufficient rotational stability for all types of intertrochanteric fractures in this age group. It underscores the need to delve deeper into the unique characteristics of these fractures and the factors that may predispose to rotational displacement in elderly individuals, which we aim to elucidate in the subsequent sections of this discussion. In 2010, Ramanoudjame et al utilized 3D CT scanning to assess rotational displacement in intertrochanteric fractures and found that approximately 40% of patients exhibited postoperative rotational displacement exceeding 15°, with excessive internal rotation of the hip being the most prevalent.⁵ However, this study primarily described the distribution of rotational displacement without exploring associated clinical factors or risk factors.

Our study highlights that rotational displacement following intramedullary nailing for intertrochanteric fractures in elderly patients is influenced by multiple clinical factors and may significantly impact postoperative recovery. Unlike previous studies focusing on younger populations, our research specifically targeted patients aged 65 years or older. Consequently, clinical outcomes in our study may be influenced by factors such as advanced age, severe osteoporosis, and internal fixation failure. This contrasts with younger cohorts where implant failure strongly correlates with rotational deviation, suggesting geriatric patients exhibit unique biomechanical tolerance thresholds. Abnormal differences in the anteversion angle of the affected hip postoperatively can lead to gait abnormalities, delayed fracture healing, secondary fractures, and even increased re-fracture rates and mortality in elderly patients.¹⁸ In this study, we not only analyzed the incidence of rotational displacement in intertrochanteric fractures but also investigated its correlation with clinical outcomes and risk factors, aiming to provide insights for guiding clinical practice.

In the present study, we observed that 33 patients (15.7%) exhibited differences in anteversion exceeding 15°; 177 patients (84.3%) were under 15°; forty-three patients (20.4%) showed reduced anteversion (indicating increased external rotation of the affected limb), ranging from −1° to −14°; in 103 patients (49.0%), anteversion increased postoperatively, ranging from 1° to 22°; sixty-four patients (30.6%) achieved restoration of normal anteversion. The proportion of differences in anteversion we observed was significantly lower than the 20% to 30% reported in previous studies.^19,20 This discrepancy may be attributed to advancements in the understanding and management of intertrochanteric fractures in recent years. On one hand, surgeons now prioritize anatomical over functional reduction; on the other hand, the introduction of novel reduction techniques and devices has significantly improved reduction quality.

Given the high reduction quality in the included patients, we categorized those with rotational displacement exceeding 15° to further analyze the impact of clinical indicators and risk factors on rotational displacement in intertrochanteric fractures. Our findings revealed that single-nail fixation, medial cortical defects, T-score >2.5, rLWT and fracture classification were the primary contributors to rotational displacement beyond 15°. These results align with previous studies, likely due to the strong association between these factors and fracture instability.⁷ In stable fractures, the anterior fracture gap visible on lateral radiographs, caused by the pull of the gluteus medius and short external rotators, can often be closed by internally rotating the distal limb, as the posterior cortex acts as a hinge.²¹ However, in unstable fractures (eg, four-part or reverse oblique fractures), rotational alignment becomes more challenging due to comminution of the posterior cortex, which disrupts its hinge function and complicates anterior cortical reduction.²²

We further evaluated complications associated with excessive differences in anteversion, such as implant failure, nonunion, and gait disturbances leading to secondary fractures, using the HHS and VAS for functional assessment. These complications significantly increase re-fracture rates and mortality in elderly patients, underscoring the necessity and relevance of such studies. Our results demonstrated that patients with rotational displacement exceeding 15° had significantly worse HHS and VAS scores at 1 year postoperatively compared to those with displacement <15°. Greater rotational displacement may affect functional recovery by altering the axis of hip mechanics. Gialanella et al²³ found by prospective observational study of 102 people with hip fracture that femoral rotational deviations is associated with lower levels of balance and functional abilities before and after rehabilitation and it adversely affects rehabilitation for patients with hip fractures. It correlated with the changes in HHS scores and VAS scores we observed (from 81.3 to 76.0 and from 1.6 to 2.5) in this study. Our predictive model demonstrates that rotational displacement ≥15° is a robust independent predictor of long-term functional impairment, aligning with clinic study showing that excessive rotation destabilizes fracture fixation.²⁴ This suggests that excessive rotational displacement adversely affects hip function and quality of life in elderly patients, potentially hindering their return to daily activities and work.²⁵

Although our results showed significant differences in rotation angles among different fixation methods, whether these differences can influence clinical outcomes remains a question that needs to be further explored. According to previous literature, small differences in the angle of rotation after femoral trochanteric fractures may cause osteoarthritis in the knee, hip and knee pain, and long-term functional recovery.^21,26,27 However, available studies have not clearly demonstrated that these small rotational differences have a clinically significant impact on functional recovery in elderly patients. Therefore, further prospective clinical studies are essential to assess the importance of these differences in actual clinical practice.

The excessive rotation observed in intertrochanteric fractures may be attributed to several factors. Elderly patients often present with multiple comorbidities, necessitating closed reduction and minimally invasive fixation to minimize surgical time and bleeding. However, these techniques may compromise the accuracy of anterior and medial cortical alignment and make intraoperative detection of rotational displacement challenge due to limited fluoroscopy. Additionally, despite satisfactory reduction, fracture displacement or rotation may occur during nail or lag screw insertion due to the wedge effect or other technical factors.²⁸

This study has several limitations. First, the small sample size and short follow-up period may limit the statistical reliability of the findings. Second, the analysis focused solely on intramedullary fixation, lacking comparative data on extramedullary fixation. Third, the postoperative weight-bearing protocol in this study deserves critical evaluation. At our institution, a conservative approach was adopted, requiring patients to maintain non-weight-bearing status for the first 4 weeks postoperatively. Delayed mobilization could theoretically exacerbate muscle atrophy and joint stiffness, confounding the assessment of rotation-related gait disturbances. Future studies should stratify patients by weight-bearing tolerance or employ randomized designs comparing conservative vs accelerated protocols in osteoporotic populations. At last, this study did not perform a priori power analysis, which may limit the detection of subtle associations. However, our post hoc analysis confirmed adequate power (78%) for the primary outcome. Future prospective studies should incorporate power calculations based on this study’s effect sizes. (Table 4)

Table 4.

Key Considerations for Achieving Rotational Stability in Geriatric Intertrochanteric Fractures

Key considerations	Recommended techniques
Medial cortical defects	- Prioritize re-establishment of medial cortical continuity
Anteversion control	- Intraoperative real-time monitoring of anterior tilt using 3D navigation- Preoperative planning with CT data of the contralateral limb (anterior inclination of the healthy side for reference)
Lateral wall integrity	- Avoiding excessive marrow expansion (preserving the amount of bone in the lateral wall)
Osteoporosis management	- Timely determination of the degree of osteoporosis- Anti-osteoporotic treatment may be considered
Reduction assessment	- Immediate postoperative 3D CT to verify quality of reduction- Dynamic C-arm fluoroscopy to assess rotational stability

Conclusion

Intertrochanteric femoral fractures in elderly patients often involve significant spatial displacement, with rotational displacement frequently going undetected intraoperatively. The way of nail fixation, presence of medial cortical disruption, T-scores exceeding 2.5, diminished rLWT and fracture classification are key factors contributing to rotational displacement and related complications. Therefore, meticulous attention to rotational alignment and the use of appropriate reduction techniques to achieve anatomical reduction are crucial for improving fracture healing rates and reducing complications such as nonunion and functional impairment. Preoperative planning must emphasize comprehensive fracture classification and rigorous bone quality assessment to stratify rotational instability risk. During surgery, multiplanar fluoroscopic imaging (AP, lateral, oblique views) is essential to precisely assess rotational alignment of fracture fragments, as residual malrotation exceeding 15° correlates with significant functional decline. This protocol ensures anatomic restoration of both cortical continuity and femoral anteversion – critical determinants of postoperative mobility preservation in elderly patients.

Footnotes

Chao Han

Xiao-dan Li

Zhe Han

Qiang Dong

Ethical approval

The study protocol was approved by the Ethics Committee of Tianjin Hospital (Approval No. 202234).

Authors’ Contributions

C.H. and X.D.L conducted the literature search and determined the studies for exclusion and inclusion. C.H. and Z.H. extracted data from the included studies, performed the meta-analysis, and drafted the manuscript. C.H. and Q.D. conceived the idea of the study, designed the study, and critically revised the manuscript for important intellectual content. All authors reviewed the paper and approved the final manuscript.

Funding

This study is supported by General Project of Multiple Investment Fund of Tianjin Natural Science Foundation (No.21JCYBJC01840).

Declaration of Conflicting Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

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