Reliable Method for Avoiding Malrotation Deformity After Intramedullary Nailing of Comminuted Femur Fractures: Clinical Validation of a Previously Described Technique

Clinical versus radiological method for adjusting rotational alignment during femoral shaft fractures intramedullary nailing and the malrotation impact on the functional outcomes: early results from a prospective cohort study

OBJECTIVES

The primary objective of the current study is to assess which is better for obtaining the proper femoral rotation during IMN of femoral fractures, the radiological or clinical method. The secondary objectives were to document malrotation's incidence and its effect on the hip and knee functional outcomes.

METHODS

Thirty-three patients with unilateral femoral shaft fractures were treated using intramedullary nails (IMN) on a usual radiolucent operative table. Intraoperative rotation adjustment was performed using a radiological method (relying on the contralateral lesser trochanter profile) in 16 patients (group A), while in 17 patients, a clinical method was used (group B). Postoperative assessment of malrotation was performed using a CT scan, and 15 degrees was the cutoff value where below is an acceptable rotation (group I) and above is true malrotation (group II). Functional assessment was performed using the Harris hip score (HHS), the Tegner Lysholm Knee Scoring Scale (TLKSS), and the Neer score.

RESULTS

The patients' mean age was 30.7 ± 9.3 years; 81.8% were males, and the left side was injured in 63.6% of patients. After a mean follow up of 18.2 ± 6.9 months, all fractures were united, and the overall mean amount of rotational difference between the fractured and the contralateral side was 14.7° ± 6.0 (3-29.4), 84.8% were in external rotation. No difference in the mean rotational deformity in group A compared to group B. Measurements were 13.9 ± 6.7 and 15.7 ± 5.5, respectively (p = 0.47). Seventeen (51.5%) patients in group I with a mean deformity of 9.8 ± 3.4 (3-14.7), while group II consisted of 16 (48.5%) patients with a mean deformity of 19.6 ± 3.7 (15.3-29.4). There was no difference in the functional scores between group I and group II; HHS was 89.4 ± 7.4 versus 87.7 ± 8.9 (p = 0.54), TLKSS was 84.6 ± 9.6 versus 80.4 ± 13.9 (p = 0.32), and Neer score was 87.9 ± 9.5 versus 83 ± 12.5 (p = 0.21) for group I and group II, respectively.

CONCLUSION

There was no difference in malrotation incidence after unilateral femoral fractures IMN with either an intraoperative clinical or radiological method for rotational adjustment; furthermore, malrotation did not affect the functional outcomes.

Measurement of Lag-Screw Anteversion With an iPhone During Trochanteric Fracture Surgery

Introduction  A useful way to easily evaluate femoral rotation during surgery for trochanteric fractures is not known. Hence, this pilot study aimed to develop an intraoperative indicator to evaluate anteversion in femoral trochanteric fractures. Material and methods Prospectively, from June 2021 to January 2022, all patients with femoral trochanteric fractures (Orthopaedic Trauma Association classification: 31A1-3) treated using a cephalo-medullary nail with a lag-screw neck-shaft angle of 125° were included in this study. During surgery, lag-screw anteversion (LS-AV) was measured using the goniometer application in an iPhone with the fractured femur table-top-plane level with the traction table floor. Accuracy was analyzed by comparing axial-projected lag-screw anteversion (AxP-LS-AV) and three-dimensional computed tomography lag-screw anteversion (3DCT-LS-AV) measurements after surgery. Results Fifty patients (14 males and 36 females) were included in the study. The mean age was 87 (range; 69-98) years; the Orthopaedic Trauma Association classifications were A1 (28 patients), A2 (18 patients), and A3 (4 patients). The mean LS-AV was 10.7° ± 6.9°, the mean AxP-LS-AV was 12.8° ± 8.3°, and the mean 3DCT-LS-AV was 13.1° ± 8.6°. The median difference between AxP-LS-AV and 3DCT-LS-AV was 3.0° (range: 0°-12°), and 40 (80%) patients had differences of ≤5° (Bland-Altman plot: inside of limit of agreement = 86%, paired t-test p = 0.7, Pearson correlation coefficient r = 0.817, p <0.001). Conclusion Femur malrotation is defined as a deformity of >15° relative to the normal contralateral limb. Intraoperative LS-AV iPhone measurement on table-top-plane standard had sufficient accuracy as an indicator of anteversion in femoral trochanteric fractures.

CT analysis of femoral malrotation after intramedullary nailing of trochanteric fractures

PURPOSE

Functional results after internal fixation of trochanteric femoral fractures may be negatively affected by healing in a non-physiological position. The aim of this study was to evaluate the occurrence and severity of femoral malrotation after nailing of trochanteric fractures.

MATERIALS AND METHODS

The authors conducted a prospective study focused on a CT analysis of malrotation after intramedullary nailing of trochanteric fractures (AO 31A1-3) in 101 patients. We recorded the type of fracture, method of anesthesia, scheduled surgery vs. acute surgery, and the surgeon's experience as possible risk factors for limb malrotation after trochanteric fracture surgeries.

RESULTS

The average extent of malrotation was 9° of internal rotation ranging from 29° of external to 48°of internal rotation. In 35% of patients, we observed a rotation greater than 15°, and in 15 patients (15%), the rotation was greater than 25°. The risk of significant internal malrotation was significantly higher than external malrotation (37 vs. 4 patients). None of the factors observed proved to be statistically significant. The effect of general anesthesia and the type of intertrochanteric fracture came closest to having a significant effect on rotational error.

CONCLUSION

Improper reduction of a trochanteric fracture is a common problem that can lead to femur malrotation. In our study, a rotational error greater than 15° occurred in 35% of the patients, but none of the monitored factors represented a statistically significant risk for this complication.

Development of an intraoperative 3D C-arm technique for torsion control of femur fractures: a cadaver study

AIM

This study aims to test the accuracy and feasibility of a measurement of femoral torsion of a 3D C-arm system (Linea aspera method) in a cadaver setting.

MATERIALS AND METHODS

A total of 11 intact femora were used. Schanz screws were inserted in the femoral bone in a parallel manner with the help of a fixed drill sleeve. Femur bones were then fractured in a controlled manner and three different internal and external torsion angles were fixed with the help of a Goniometer. After that, a 3D scan was performed. The 3D data set was analyzed using a radiologic software (Visage 7, Visage Imaging Inc, USA). Measurements were then compared in the two methods with a dependent t test.

RESULTS

Specific measurements for different angles did not show any differences between those two utilities.

CONCLUSION

Intraoperative estimation of femoral antetorsion using a 3D C-Arm system and the Linea aspera method seems to be an accurate and feasible method. Nevertheless, more studies with higher patient numbers, comparison to CT seems to be the next step and can be recommended.

Can Views of the Proximal Femur Be Reliably Used to Predict Malrotation After Femoral Nail Insertion? A Cadaver Validation Study

INTRODUCTION

We investigated the relationship between the size of the lesser trochanter visualized on an AP view of the hip and femoral rotation after femoral shaft fracture fixation. We hypothesized that the amount of the lesser trochanter visualized can accurately detect differences in femoral shaft rotation.

METHODS

Sequential fluoroscopic images of 19 matched pairs of cadaver femora were obtained of the proximal femur at 10° increments of internal and external rotation. The relationship between the percentage of the lesser trochanter and the angle of femoral rotation was assessed by regression analysis.

RESULTS

Rotation of the proximal femur follows a relatively linear relationship centered around the neutral rotation position. A 10% change in the lesser trochanter size corresponds to approximately 7° of femoral rotation.

CONCLUSION

The relationship between the size of the lesser trochanter visualized and the degree of femoral rotation after femoral shaft fracture fixation is approximately linear and sensitive to relatively small changes in rotation, making it potentially useful for assessing malrotation after femoral shaft fracture fixation.

Use of Inherent Anteversion of an Intramedullary Nail to Avoid Malrotation in Comminuted Femur Fractures: A Prospective Case- Control Study

OBJECTIVES

To (1) evaluate using the inherent anteversion of a second or third generation femoral nail to set the version of the femur during locked intramedullary nailing of comminuted femoral shaft fractures (Espinosa Technique [ET]) and compare it with our traditional method (traditional group [TG]) and (2) assess the variation of anteversion because of the inherent play in the nail itself.

DESIGN

A prospective IRB-approved study.

SETTING

Academic US Level 1 Trauma Center.

PATIENTS

Fifty-two consecutive patients with comminuted femur fractures all completed the study.

INTERVENTION

The first 27 patients had the anteversion determined using the patellar shadow and lesser trochanter (TG), and the next 25 patients were treated by ET.

MAIN OUTCOME MEASURE

Computed tomography scanogram for femoral anteversion and length in the normal versus operated femur.

RESULTS

A >15 degree difference from native to operated legs was found in 8/27 TG (29%, 95% CI 15.3%-54.2%), with a mean difference of 11.6 ± 10.2 degrees (95% CI 8.8-16.17) verses 1/25 in the ET group (2.5%, 95% CI 0%-15.3%), with a mean difference of 4.8 ± 6.2 degrees (95% CI 1.38-8.9) (P = 0.0068). There was a 5 degree variability in our ability to center the proximal locking screw in the femoral head and 5 degrees variation in distal locking.

CONCLUSIONS

The inherent anteversion of a second generation nail can be used to minimize malrotation of the femur after comminuted fractures during locked intramedullary nailing in patients with normal anteversion and is superior to our present fluoroscopic technique.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Is the Lesser Trochanter Profile a Reliable Means of Restoring Anatomic Rotation After Femur Fracture Fixation?

BACKGROUND

Restoring normal femoral rotation is an important consideration when managing femur fractures. Femoral malrotation after fixation is common and several preventive techniques have been described. Use of the lesser trochanter profile is a simple method to prevent malrotation, because the profile changes with femoral rotation, but the accuracy of this method is unclear.

QUESTIONS/PURPOSES

The purposes of this study were (1) to report the rotational profiles of uninjured femora in an adult population; and (2) to determine if the lesser trochanter profile was associated with variability in femoral rotation.

METHODS

One hundred fifty-five consecutive patients (72% female and 28% male) with a mean age of 32 years (range, 12-56 years) with a CT scanogram were retrospectively evaluated. Patients were included if CT scanograms had adequate cuts of the proximal and distal femur. Patients were excluded if they had prior hip/femur surgery or anatomic abnormalities of the proximal femur. CT scanogram measurements of femoral rotation were compared with the lesser trochanter profile (distance from the tip of the lesser trochanter to the medial cortex of the femur) measured on weightbearing AP radiographs. These measurements were made by a single fellowship-trained orthopaedic surgeon and repeated for intraobserver reliability testing. Presence of rotational differences based on sex and laterality was assessed and correlation of the difference in lesser trochanter profile to the difference in femoral rotation was determined using a coefficient of determination (r).

RESULTS

The mean femoral rotation was 10.9° (SD ± 8.8°) of anteversion. Mean right femoral rotation was 11.0° (SD ± 8.9°) and mean left femoral rotation was 10.7° (SD ± 8.7°) with a mean difference of 0.3° (95% confidence interval [CI], -1.7° to 2.3°; p = 0.76). Males had a mean rotation of 9.4°(SD ± 7.7°) and females had a mean rotation of 11.5° (SD ± 9.1°) with a mean difference of 2.1° (95% CI, -0.1° to 4.3°; p = 0.06). Mean lesser trochanter profile was 6.6 mm (SD ± 4.0 mm). Mean right lesser trochanter profile was 6.6 mm (SD ± 3.9 mm) and mean left lesser trochanter profile was 6.5 mm (SD ± 4.0 mm) with a mean difference of 0.1 mm (-0.8 mm to 1.0 mm, p = 0.86). The lesser trochanter profile varied between the sexes; males had a mean of 8.3 mm (SD ± 3.4), and females had a mean of 5.9 mm (SD ± 4.0). The mean difference between sexes was 2.5 mm (1.5-3.4 mm; p < 0.001). The magnitude of the lesser trochanter profile measurement and degree of femoral rotation were positively correlated such that increasing measures of the lesser trochanter profile were associated with increasing amounts of femoral anteversion. The lesser trochanter profile was associated with femoral version in a linear regression model (r = 0.64; p < 0.001). Thus, 64% of the difference in femoral rotation can be explained by the difference in the lesser trochanter profile. Intraobserver reliability for both the femoral version and lesser trochanter profile was noted to be excellent with intraclass correlation coefficients of 0.94 and 0.95, respectively.

CONCLUSIONS

This study helps define the normal femoral rotation profile among adults without femoral injury or bone deformity and demonstrated no rotational differences between sexes. The lesser trochanter profile was found to be positively associated with femoral rotation. Increasing and decreasing lesser trochanter profile measurements are associated with increasing and decreasing amounts of femoral rotation, respectively.

CLINICAL RELEVANCE

The lesser trochanter profile can determine the position of the femur in both anteversion and retroversion, supporting its use as a method to restore preinjury femoral rotation after fracture fixation. Although some variability in the rotation between sides may exist, matching the lesser trochanter profile between injured and uninjured femora can help reestablish native rotation.