Impact of operative position on rotational alignment after intramedullary nailing of trochanteric fractures: a comparative analysis of lateral decubitus versus supine position

Abstract

Background

Fixation of trochanteric fractures with an intramedullary nail in a non-physiological position can cause poor functional outcomes. The aim of this study is to evaluate the effect of intraoperative patient position on rotational alignment in intramedullary nail fixation of trochanteric fractures.

Methods

The femoral rotational alignment of 84 trochanteric fracture patients who underwent intramedullary nailing was measured by computed tomography (CT) images. Patients were divided into two groups: the supine position on the fracture table (FT) (Group 1, n = 42) and the lateral decubitus (LD) position (Group 2, n = 42). Femoral malrotation angles were measured and divided into three subgroups: insignificant, significant, and excessive. The number of intraoperative fluoroscopy images, preparation time, surgery time, and anesthesia time in both groups were compared.

Results

The malrotation degrees of patients in Group 1 ranged from 17° external rotation (ER) to 57° internal rotation (IR), with a mean of 10° IR. Of the patients in Group 1, 27 were insignificant, 5 were significant, and 10 were in the excessive subgroup. The malrotation degrees of patients in Group 2 ranged from 33° ER to 47° IR, with a mean of 11° IR. Of the patients in Group 2, 21 were insignificant, 12 were significant, and 9 were in the excessive subgroup. There was no statistically significant relationship between patient position and malrotation angle. The number of intraoperative fluoroscopy images, preparation time, and anesthesia time were statistically lower in Group 2. There was no statistically significant difference between Group 1 and Group 2 in terms of surgery time.

Conclusion

Intramedullary nailing in the LD position is a reliable and practical surgical method in the treatment of femoral trochanteric fractures since there is no need for the use of a FT, the surgeon is exposed to less radiation, there is no risk of complications related to the traction of the FT, and there is a shorter operation time.

Introduction

With the developments in the field of health in the world, as a result of the prolongation of the average human lifespan, diseases due to the increasing elderly population appear more frequently. Hip fractures, which are common in the geriatric population, have been an important part of the workload of orthopedic surgeons in recent years. Intramedullary nails applied with the aim of osteosynthesis are a common treatment method for hip fractures because of their lower infection rate, faster mobilization, and less invasiveness. Among the most common complications in intramedullary nailing are mechanical failures as a result of improper fixation of the implant. Femoral rotational malalignment can lead to a decrease in patient satisfaction and different functional limitations in the postoperative period, such as decreased range of motion in the hip and knee joints, abnormalities in the walking phase, and malunion [1–3].

The surgeon’s comfort and ease of fracture reduction are undoubtedly important intraoperative factors affecting the prognosis in the surgical treatment of hip fractures. In intramedullary nailing of trochanteric fractures, the lateral decubitus (LD) position takes a shorter time compared to the fracture table (FT) position, provides good fracture reduction and ease of implant placement [4, 5]. The aim of our study is to evaluate the effect of LD position and FT on rotational alignment in patients who underwent intramedullary nailing due to a hip fracture. To the best of our knowledge, this is the first study to make a computed tomography (CT) analysis of femoral malrotation after intramedullary nail fixation of trochanteric femur fractures in different intraoperative positions and to contribute to the literature in this respect.

Materials and methods

Patients data and acquistion

The study commenced following approval number 2023/4239 from the Necmettin Erbakan University Non-Pharmaceutical and Medical Device Research Ethics Committee, with informed consent obtained from all patients for being included in the study, adhering to the principles outlined in the Declaration of Helsinki. The study was conducted in a retrospective design that evaluated patients in two centers where advanced trauma surgeries were performed. Patients who underwent intramedullary proximal femoral nail surgery between January 1, 2022, and April 1, 2023 for femoral trochanteric fractures were analyzed retrospectively for types 31A2 and 31A3 (unstable trochanteric fractures) in the Arbeitsgemeinschaft für Osteosynthesefragen (AO) classification. Exclusion criteria were AO 31A1 fractures (stable trochanteric fractures), a history of previous surgery in either femur, patients with hip dysplasia, patients undergoing intramedullary nailing for pathological fractures, patients in whom CT imaging is not possible for comorbid diseases or other reasons, and patients who underwent general anesthesia. After their vitals were stable in the postoperative period, low-dose CT (including the proximal and distal femur) was obtained in patients who met the inclusion criteria (CT CC, Siemens, Erlangen, Germany) [6]. 84 patients whose records were retrospectively reviewed were divided into two groups: Group 1 (n = 42) consisted of trochanteric fractures operated on in the supine position on the FT, and Group 2 (n = 42) consisted of trochanteric fractures operated on in the LD position.

Surgical technique

All of the patients included in the study were treated by two orthopedic surgeons who are experts in the field of orthopedics and have at least six years of experience. The same type of spinal anesthesia was applied to the patients included in our study because it was thought to affect fracture reduction and rotation. The rotation of the extremities on the fractured side of the patients who were operated on both on the FT and in the LD position was aimed at being neutral with respect to the position of the patella. Care was taken to use the same brand of locked proximal femoral nail in all patients (Zimed, Gaziantep, Turkey) and to place the tip-apex distance of the nail below 25 milimeters in fluoroscopy imaging. In all patients, the distal locking screw was placed past both cortices.

In the LD position, patients were positioned with good support for the pelvis and shoulders, while care was taken not to apply pressure to the abdomen. To avoid loading the shoulder and arm of the lower side with the weight of the chest, support was placed in the axilla. Attention was given to protecting the deltoid muscle tissue of the lower side from ischemia and neurovascular injury. The upper leg was kept in extension, while the lower leg was fixed in flexion. The C-arm fluoroscopy device was adjusted to capture both anteroposterior (AP) and lateral views of the fracture site. For patients operated on the FT, traction was applied to the limb to be operated on. Plaster padding was wrapped around the skin to prevent neurovascular injury both proximally and distally on this limb. The contralateral limb was stabilized with an apparatus for abduction and flexion. The C-arm fluoroscopy device was adjusted to capture both AP and lateral views. The clinical pictures related to the operative positions of the patients are shown in Fig. 1.

Fig. 1.

A The patient’s preparation for surgery in the lateral decubitus position is depicted. B The positioning of the C-arm fluoroscopy device and the implantation procedure in the lateral decubitus position are illustrated. C The patient’s preparation for surgery in the fracture table position is depicted. D The positioning of the C-arm fluoroscopy device and the implantation procedure in the fracture table position are illustrated

Radiological and clinical evaluation

Postoperative bilateral femoral CT images obtained before discharge were examined to evaluate rotational alignment. Rotational alignment was measured using a method described by Jeanmart et al. and used in previous studies [7, 8]. In this method, the anteversion angle is measured by the angle between the two lines formed on the axial CT images. The first line is formed to cross the posterior border of the femoral condyles tangentially, and the second line is formed to divide the femoral head and neck into two equal parts (Fig. 2). The rotational alignment was evaluated by measuring the angle between these two lines in the fractured and intact extremities. Theoretically, this angle value decreases in the extremities in the external rotation position and increases in the extremities in the internal rotation position. In the case of retroversion (extremity with advanced external rotation), this angle value was recorded as negative. Since the anteversion angle would increase in patients who underwent reduction and fixation in internal rotation, all these angle values in these extremities were recorded as positive values (Fig. 3). In addition, the number of intraoperative fluoroscopy images of the patients, the time from the beginning of anesthesia to the skin incision (preparation for surgery), the surgical time from the first skin incision to the completion of the skin integrity, and the total anesthesia time were also analyzed retrospectively.

Fig. 2.

Images in parts A, B, and C show the operating extremity. The image in A is the line that divides the femoral head and neck in the operated extremity; the image in B is the line tangential to the posterior condyles in the distal femur in the operated extremity; the image in C superposes the images in A and B and shows the rotation angle between the two lines. Since the red line passing through the femoral head and neck is more vertical, this extremity is anteverted, and this angle takes a positive ( +) value. The operated extremity was anteverted, and the angle was measured at + 19°. The images in sections D, E, and F show the intact extremity. In this extremity, since the two lines are parallel to each other, the rotation angle is 0, and this hip is not anteverted or retroverted but neutral. The operated extremity has a 19° malrotation angle with respect to the intact extremity and is included in the significant subgroup

Fig. 3.

Images in parts A, B, and C show the operating extremity. Since the red line passing through the femoral head and neck is more vertical, this extremity is anteverted, and this angle takes a positive ( +) value. The operated extremity was measured at + 24°. The images in sections D, E, and F show the intact extremity. Since the line passing tangentially from the posterior of the distal condyles of the femur is more vertical, this extremity is retroverted and takes a negative (-) value. The intact extremity was measured at -4°. The operated extremity has a 28° malrotation angle with respect to the intact extremity and is included in the excessive subgroup

Statistical analysis

The data obtained in the research were analyzed using the SPSS (Statistical Package for Social Sciences) for Windows 25.0 program. Descriptive statistical methods (number, percentage, mean, and standard deviation) were used while evaluating the data.

In order for the tests and results to be reliable, the measurements must also be reliable. In this context, the reliability of the scale was examined with Cronbach’s alpha. Post-hoc power analysis with an alpha of 0.05 demonstrated a power of 80% for this study. Measurement tools were examined for their normality with the Shapiro–Wilk test of normality. Accordingly, it was determined that the normal distribution was not achieved. The Mann–Whitney U test was used for the difference between two independent groups. Chi-square analysis was used for the relationship between position and angle change. The minimum (min), maximum (max), median, mean, and standard deviation (SD) values of these parameters were recorded, and the level of significance was determined as a p value < 0.05 in all tests.

When the previous studies on rotational malalignment were examined, a ≤ 15° rotation difference between the operated extremities and healthy extremity was taken as an acceptable value [9]. The patients were divided into three subgroups: insignificant malrotation (< 15°), significant malrotation (15°–25°), and excessive malrotation (> 25°) [10].

Results

Between January 2022 and April 2023, a total of 266 patients underwent surgery. However, 182 of these patients did not meet the inclusion criteria and were therefore excluded. Consequently, 84 patients who met the inclusion criteria were retrospectively analyzed. The mean age was calculated to be 75.87 ± 11.16 years. Of these patients, 38 were male (45.2%) and 46 were female (54.8%).

The degrees of malrotation in Group 1 ranged from 17° external rotation to 57° internal rotation, with an average of 10° internal rotation. Of the patients in Group 1, 27 patients (64,3%) were in the insignificant subgroup, 5 patients (11,9%) were in the significant subgroup, and 10 patients (23,8%) were in the excessive subgroup. The degrees of malrotation in Group 2 ranged from 33° external rotation to 47° internal rotation, with an average of 11° internal rotation. Of the patients in Group 2, 21 patients (50%) were in the insignificant subgroup, 12 patients (28,6%) were in the significant subgroup, and 9 patients (21,4%) were in the excessive subgroup. Data on the severity of the change in malrotation angles (significant, unsignificant, excessive) in both groups are given in Table 1. When the rotational angle changes of both groups were compared, no statistically significant relationship was found (p = 0.267). In addition, when the relationship between the intraoperative position of the patients and the severity of malrotation was examined by chi-square analysis, it was seen that there was no significant relationship (p = 0.158). It was observed that the number of intraoperative fluoroscopy images, the preparation time of the patient for surgery, and the duration of anesthesia were statistically lower in Group 2 compared to Group 1 (p = 0.013, p = 0.008, and p = 0.004 respectively). No significant difference was observed in terms of the duration of surgery, in which skin integrity was achieved completely from the skin incision (p = 0.081). The data, including the change of these factors in Group 1 and Group 2 are given in Tables 1 and 2, and Fig. 4.

Table 1.

Chi-square analysis result and graph classifying the severity of malrotation (Insignificant, significant and excessive) in Group 1 and Group 2. (n: number)

			Operation position
			Fracture table (Group 1)	Lateral decubitus (Group 2)
Angle Change	Insignificant	n (%)	27 (64,3)	21 (50,0)
	Significant	n (%)	5 (11,5)	12 (28,6)
	Excessive	n (%)	10 (23,8)	9 (21,4)
Pearson chi-square = 3,685; p = 0,158

Table 2.

Comparing and statistical analysis of malrotation angle change, number of fluoroscopy images, preparation time, surgery time and anesthesia time in Group 1 and Group 2. (^*: p < 0,05)

Parameter	Group	Mean ± SS	Median (Min–Max)	p value
Malrotation Angle	Group 1	13,85 ± 12,75	16,07 (1–61)	0,267
	Group 2	11 ± 12,04	14 (0–49)
Fluoroscopy Number	Group 1	75,11 ± 10,47	76 (56–97)	0,013*
	Group 2	68,88 ± 10,64	67,5 (52–87)
Preparation Time	Group 1	15,78 ± 3,49	16 (10–23)	0,008*
	Group 2	13,61 ± 3,4	13,5 (8–19)
Surgery Time	Group 1	56,14 ± 7,93	54,5 (46–79)	0,081
	Group 2	53,38 ± 6,56	51 (45–69)
Anesthesia Time	Group 1	71,66 ± 7,71	70,5 (62–95)	0,004*
	Group 2	66,95 ± 6,14	65 (58–80)

Fig. 4.

Malrotation angle changes (A), number of fluoroscopy images (B), preparation times, surgery times and anesthesia times, C according to the intraoperative position

In order to evaluate whether the change in rotation angle is significant in patients who underwent intramedullary nailing regardless of the operating position, the angle measured in the intact extremities of the patients was taken as the preoperative rotation angle, and the angle measured in the operated extremities was taken as the postoperative rotation angle. Postoperatively, there was a statistically significant increase in the direction of internal rotation (anteversion) in both groups, while this increase was less in patients in Group 2 (p = 0.001, p = 0.041, respectively) (Table 3).

Table 3.

Comparison of the values of rotation angles preoperatively (intact extremity) and postoperatively (operated fractured extremity) (^*: p < 0,05)

Position	Extremity	Mean	± SD	Q25	Median	p value
Group 1	Intact (preoperative)	10,67	9,37	5,00	8,00	0,001*
	Fractured (postoperative)	17,76	11,11	13,00	18,00
Group 2	Intact (preoperative)	11,36	11,99	5,00	9,50	0,041*
	Fractured (postoperative)	16,05	12,00	7,00	12,50

Among the patients included in our study, it was determined that only one patient developed peroneal nerve stenosis, and no other acute complications developed in all the remaining patients (in the postoperative period, before discharge, or during the stay in the hospital). In this patient, who developed peroneal nerve palsy, it was observed that his complaints resolved at the end of the postoperative 4th month, and we evaluated the situation in this patient who was operated on the FT, as traction-induced neuropraxia.

Discussion

The incidence of rotational malalignment in patients who underwent fracture fixation with intramedullary nail after femur fractures is between 17 and 40%, and this rate is the most common complication among nail-related anatomical abnormalities [9, 11–14]. It is neglected because more than half of the patients with this complication are asymptomatic and it is difficult to detect rotational malalignment with X-rays used in routine imaging [15]. Ignoring rotational alignment in fracture reduction may be a risk factor for complications ranging from limitation of physical activities to nonunion in the postoperative period. Studies investigating the factors affecting rotational alignment in patients undergoing nailing have increased in recent years with the development of imaging standards. However, these studies on rotational alignment mostly focused on diaphyseal fractures of the femur, and extensive studies were conducted [12–15]. In our study, we aimed to show whether the use of a FT has an effect on postoperative rotational alignment in trochanteric fractures, about which there are more limited studies in the literature regarding postoperative rotational deformity.

The use of CT in the examination of the rotational alignment of the femur allowed for more accurate results compared to clinical assessments. In the first studies evaluating the rotational alignment of patients operated on for femoral fractures by clinical examination, it was reported that malrotation was close to 0% [16, 17]. However, in the following years, studies evaluating rotational alignment using CT imaging reported that the malrotation rate was greater than 40% [15, 18, 19]. Similarly, in our study, rotational alignment was evaluated using CT, and a malrotation angle greater than 15° was observed in 45% of the patients. We think that the use of CT instead of clinical examination will be evaluated more objectively in the examination of rotational alignment.

The distortion in rotational alignment affects the entire extremity and affects the postural structure and mobilization of the patient. There are studies reporting that changes in the anteversion angle after osteosynthesis cause osteoarthritis in the knee later on [15, 20]. While the differences between the anteversion angles of both femurs are considered variations up to 10°, anteversion differences greater than 15° can cause symptoms such as hip and knee pain, and in the long term, it can cause arthrosis due to the change in joint biomechanics [7, 9, 18, 21]. In order to avoid these complications, we have to develop and use techniques and devices to prevent rotational malalignment. Several methods have been previously described that can reduce rotational malalignment in femoral fractures. Marchand et al. stated that the alignment of the trochanter minor is the most reliable marker in the evaluation of rotational alignment, but they said that it did not give satisfactory results [22]. Tornetta et al. used C-arm; Wilharm et al. used perioperative CT and reported that rotational malalignment was reduced [23, 24]. However, they stated that these two methods have disadvantages such as prolonging the operation time, increasing the number of fluoroscopy images, and costing the system. However, we predict that malrotation rates will decrease in intramedullary nailing of proximal femur fractures with the increase in technological developments and the more frequent use of CT navigation systems in daily practice.

Abubeih et al. examined the rotational alignment of the femur in 31 proximal femoral fractures with intramedullary nailing in the LD position and found a malrotation greater than 10° in 56% of the patients [8]. They stated that although it is easy to reach the nail entry point in the LD position and saves time, it is necessary to be careful about rotational alignment. However, in the study of Abubeih et al., it was observed that they could not provide adequate standardization in the patient groups since they added subtrochanteric fractures of the femur in addition to AO 31A1-3-type fractures of the femur. In addition, the lack of a patient group who underwent intramedullary nail application on the FT for comparison with the results of the patients is another limitation of the aforementioned study. In our study, we only included patients who had intramedullary nailing applied to AO 31A2-3-type fractures of the femur and examined two different patient groups who were operated on in the LD position and in the FT position. We found a malrotation angle of more than 15° in 50% of the patients who underwent intramedullary nailing in the LD position and in 35.7% of the patients who underwent intramedullary nailing on the FT, and these results were close to the literature.

De Oliveira et al. reported satisfactory clinical results in 19 patients with proximal femur fractures who applied cephalomedullary nails in the LD position [4]. They also stated that the LD position provides an advantage in terms of fracture reduction and implant positioning compared to the supine position. However, the limited number of patients and the absence of the patient group operating in the supine position are the limitations of this study. In our study, although there was no significant difference between the two positions in terms of malrotation, we think that choosing the LD position is a superior, practical, and preferable method compared to the supine position on the FT in terms of preparation time, operation time, and number of fluoroscopy images.

In the study of Maler et al., the rate of patients with a malrotation angle of more than 15° was found to be 35% in patients operated on for trochanteric fracture [10]. However, the inclusion of patients who underwent both spinal anesthesia and general anesthesia limited this study. When spinal anesthesia and general anesthesia are compared, we think that malrotation in the extremity occurs less frequently due to the complete inhibition of muscle tone in the lower extremity with spinal anesthesia [25, 26]. In order to avoid complications such as respiratory depression in elderly hip fracture patients with high comorbidities, minimal muscle relaxants are used in general anesthesia, or a laryngeal mask is applied without muscle relaxants. This causes the continuation of muscle tonus in the lower extremities, and as a result, it makes it difficult to achieve fracture reduction and extremity alignment. In our study, spinal anesthesia was applied to all the included patients. Despite this, we think that the high rate of malrotation is due to the presence of a large number of muscle insertions in the hip and the fact that this region is exposed to excessive rotational force.

In the study by Sonmez et al., in which they compared 82 patients who underwent proximal femoral nailing in the FT and LD positions, they reported that the parameters of preparation time, surgical time, and fluoroscopic exposure were lower in patients operated in the LD position [27]. In our study, preparation time and fluoroscopic exposure were similarly lower in patients with nails in the LD position, but we did not observe a significant difference in terms of surgical time. In the study of Sonmez et al., we think that not using CT as an imaging method and not evaluating rotational alignment limit the results of the study.

In this study, meticulous attention was paid to the position of the patella during the evaluation of intraoperative rotation in patients undergoing surgery in both the LD position and on the FT. However, Friederichs et al. have reported that employing additional fluoroscopic images in the LD position could facilitate more precise implant placement [28]. According to their findings, achieving optimal implant alignment involves positioning the femoral condyles one above the other, with the femoral head visualized two-thirds anterior to and one-third posterior to the shaft axis, indicating appropriate neutral rotation. While this methodology wasn’t utilized in our study, we acknowledge its potential utility in assessing rotational alignment in the LD position. Furthermore, it’s imperative to recognize that surgical proficiency plays a pivotal role in avoiding rotational malalignment during fracture reduction. Rüden et al., in their investigation of 453 patients, identified 13 cases of intramedullary nail failure attributed to inadequate fracture reduction, particularly due to suboptimal surgical performance [29].

The first of the limitations of our study is that these operations, which were performed in two different positions, were performed by two different orthopedic surgeons. Another limitation of our study is the possibility of anatomical variation and differences in femoral anteversion angles in both hips. In such a scenario, it may lead to an incorrect measurement of the malrotation angle. However, it is known that the difference in both femoral anterversion angles does not usually exceed 3°. We believe that this factor did not affect the result of the study much [30].

Conclusion

Inadequate reduction and fixation of trochanteric fractures often cause femoral malrotation. Although rotational malalignment was observed in in nearly half of all patients examined in our study, it was found that there was no statistically significant difference in the rotational malaligment complication of proximal femoral nailing in the LD position without using the FT, compared to the patients using the FT in the supine position. Intramedullary nailing of trochanteric fractures in the LD position is considered a more practical approach than utilizing a FT, as it typically involves shorter preparation time, reduced anesthesia duration, and fewer fluoroscopic shots with the C-arm.

Authors’ contributions

Conceptualization, A.Yur., N.M., M.K., A.Yıl. and F.D.; methodology, A.Yur., N.M., M.K., A.Yıl. and F.D.; formal analysis, A.Yur, N.M. and M.K.; investigation, A.Yur, N.M.,F.D. and A.T.; writing—original draft preparation, A.Yur, N.M.,F.D. and A.Yıl.; writing—review and editing, D.T., F.D. and A.Yıl.; project administration, D.T., F.D. and A.Yıl.

Funding

This research received no specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Availability of data and materials

The datasets used and/or analysed during the current study are available from the corresponding author on reasonable request.

Declarations

Ethics approval and consent to participate

This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Necmettin Erbakan University Non-Pharmaceutical and Medical Device Research Ethics Committee (with decision number 2023/4239). Informed consent was obtained from all patients for being included in the study.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.