Comparison of femoral neck shortening and outcomes between in situ fixation and fixation after reduction for severe valgus-impacted femoral neck fractures

Analysis of risk factors for modification of femoral offset after internal fixation of Garden I and II femoral neck fractures

BACKGROUND

The concept of restoring the femoral offset is well established during hip replacement surgery, but is less well known when treating Garden I or II femoral neck fractures by internal fixation. And yet, the therapeutic aim for these fractures is to restore this native parameter as best possible. The aim of this study was to identify the risk factors for reduction of femoral offset after union of a Garden I or II femoral neck fracture treated by internal fixation.

HYPOTHESIS

After internal fixation of a femoral neck fracture, certain factors may contribute to reducing the femoral offset, which itself has been identified as being responsible for altering the patients' quality of life and functional outcomes.

MATERIALS AND METHODS

This multicenter study included 193 patients who had a Garden I or II femoral neck fracture treated by cannulated screws or a sliding compression screw-plate. The difference between the femoral offset in the operated hip and that of the contralateral hip was measured in weightbearing patients after the fracture had healed. This difference was the primary outcome measure. Univariate and multivariate analyses were done to look for risk factors contributing to femoral neck shortening.

RESULTS

Based on the univariate analysis, being more than 85 years of age, having a Garden I fracture, and cannulated screw fixation were associated with a significantly greater reduction in the femoral offset. In the multivariate analysis, only Garden I fractures were associated with a greater reduction in femoral offset.

DISCUSSION

Garden I fractures were associated with a greater reduction in the offset, although there was no evidence that this change was related to early weightbearing. By identifying this risk factor, surgeons can optimize the indications given that the treatment of these fractures is still widely debated and there is still no consensus as to the best method.

LEVEL OF EVIDENCE

IV.

Comparison of dynamic compression system versus multiple cancellous screws in the treatment of femoral neck fractures in young adults

INTRODUCTION

Femoral neck fractures have posed a significant global healthcare challenge and had notable impacts on the quality of life. Current treatment strategies for femoral neck fractures in young individuals have varied, emphasizing the need for optimal fixation methods. This study compared the clinical and radiological outcomes of the dynamic compression system (DCS) and multiple cancellous screws (MCS) methods.

METHODS

This retrospective study included a total of 275 young adults with fresh femoral neck fractures treated with DCS and MCS. A matching analysis with a 1:1 ratio based on age, gender, fracture classification, and reduction quality was conducted. Demographic data were recorded, and comparisons were made according to follow-up time (FUT), hospitalization period, operation duration, femoral neck shortening, caput-collum-diaphysis (CCD) angle, Harris Hip Score (HHS), and post-operative complications.

RESULTS

A total of 42 fractures were matched with a median age of 42 years (range, 22-48). In the DCS group, vertical neck shortening (median 1.92) was significantly lower than that in the MCS group (median 4.53) (P < 0.05). In the DCS group, horizontal femoral neck shortening, resultant femoral neck shortening, the amount of change in CCD angle, and HHS were 0.57 mm (0.43, 4.74 mm), 1.82 mm (0.40, 3.53 mm), 0.13° (-0.78°, 1.80°), and 91 (85-93), respectively. They were all non-significant than 1.00 mm (0.56, 6.23 mm), 2.74 mm (1.59, 6.71 mm), -0.18° (-1.11°,1.85°), and 91 (75, 93) in the MCS group, respectively (P > 0.05). There was no statistical difference in FUT, hospitalization period, operation time, and post-operative complications at the latest follow-up (P > 0.05). There were no complications such as pulmonary embolism, deep vein thrombosis, and incision infection reported.

CONCLUSION

DCS and MCS demonstrated effectiveness in treating femoral neck fractures in young adults. The DCS implant provides additional stability in the vertical axis. A prospective randomized controlled study with a large sample size was needed to validate these findings.

Femoral neck shortening as a sequela of internal fixation for femoral neck fractures and its effect on the coronal alignment of the limb: a pilot study

INTRODUCTION

Femoral neck shortening is a common phenomenon following osteosynthesis for femoral neck fractures, which was shown to have a negative effect on hip function. There is paucity of literature on the effect of shortening on the ipsilateral limb mechanical axis and knee coronal alignment. We hypothesized that postoperative femoral neck shortening can alter the limb's mechanical axis into valgus.

METHODS

Of 583 patients screened, 13 patients with severe neck shortening (< 10 mm) following femoral neck fracture fixation, were found eligible and agreed to participate. A full-length lower limb radiographs were obtained and radiographic parameters (offset, neck-shaft angle, HKA, mLPFA, mDLFA, mMPTFA, MAD, MAD-r) as well as functional scores were obtained.

RESULTS

Statistically significant differences in mechanical axis deviation ratio (MAD-r) were found between the ipsilateral and the contralateral extremities (0.41 ± 0.16 versus 0.55 ± 0.11, p = 0.03). A correlation between femoral neck length differences and MAD was not statistically significant although a tendency towards lateral deviation of the mechanical axis was noted (r = - 0.5, p = 0.077). A negative correlation was found between a greater difference in the femoral neck length and the SF12 score, both in the physical and the mental parts (r = - 0.69, p = 0.008; r = - 0.58, p = 0.035, respectively).

CONCLUSION

We found a more lateralized mechanical axis in limbs that demonstrated post-operative ipsilateral femoral neck severe shortening. These findings may provide a possible explanation and rationale for knee pain and perhaps for the development of knee osteoarthritis as a sequalae of femoral neck shortening. Further investigation and larger cohort, long-term studies are needed to further explore this hypothesis.

Postoperative Valgus Deformity and Progression of Ostheoarthritis in Non-Displaced Femoral Neck Fractures

Purpose

Nondisplaced femoral neck fractures have traditionally been treated with in situ fixation. However, poor surgical and clinical outcomes have been reported for fractures with valgus deformity >15°, and the reduction of valgus impaction has recently been emphasized. In addition, early degenerative osteoarthritis can be caused by cam-type femoroacetabular impingement after healing of femoral neck fractures. This study was designed with the objective of confirming the difference in progression of radiographic osteoarthritis according to the severity of the valgus deformity.

Materials and Methods

Patients who underwent internal fixation using multiple cannulateld screws for management of nondisplaced femoral neck fractures were divided into two groups: high valgus group (postoperative valgus angle ≥15°) and low valgus group (postoperative valgus angle <15°). Evaluation of demographic data and changes in the joint space width from the immediate postoperative period to the latest follow-up was performed.

Results

A significant decrease in joint space width in both hip joints was observed in the high valgus group when compared with the low valgus group, including cases with an initial valgus angle less than 15° and those corrected to less than 15° of valgus by reduction. No complications requiring surgical treatment were observed in either group; however, two cases of avascular necrosis, one in each group, which developed in the low valgus group after reduction of the fracture, were followed for observation.

Conclusion

Performing in situ fixation in cases involving a valgus deformity ≥15° in non-displaced femoral neck fractures may cause accelerated narrowing of the hip joint space.

Simple Minimally Invasive Method to Reduce Valgus-Impacted and Tilted Femoral Neck Fractures without Soft Tissue or Cartilage Injury: Radiological and Clinical Results

OBJECTIVE

This is a rare study comparing the radiological and functional outcomes of fixation after reduction with in situ fixation group using Femoral Neck System (FNS). The aim of this study was to introduce a simple, innovative, minimally invasive method to reduce valgus-impacted and tilted femoral neck fractures without soft tissue or cartilage injury.

METHODS

A retrospective comparative analysis of 46 patients between May 2020 and February 2022 was performed. In the control group, 23 patients underwent in situ fixation without reduction. In the study group, another 23 patients were managed by fixation after reduction using a percutaneous pull-out technique with a full threaded Steinmann pin. Caput-collum-diaphysis (CCD) angle, tilt, and femoral neck shortenings were compared between the two groups. In addition, Harris Hip Score (HHS) was evaluated and compared at 1 year after surgery. Basically, independent samples t-test was used to compare radiological and functional results.

RESULTS

Patients' initial valgus and tilt angles were not significantly different between the groups (n.s.). However, the CCD and tilt angles measured immediately and at one year postoperatively were significantly different between the groups (p < 0.05). Regarding femoral neck shortening, shortening in the three directions, the x, y, and z vectors, was significantly less in the reduction group immediately postoperatively and at 1 year post-surgery (p < 0.05). The mean HHS at 1 year postoperatively was 79.7 ± 8.4 in the in situ fixation group and 87.9 ± 6.6 in the reduction groups, and there was a significant difference (p < 0.05).

CONCLUSION

The pull-out method with a threaded Steinmann pin to reduce valgus-impacted and tilted femoral neck fracture is safe and effective for accomplishing anatomical restoration. This may achieve successful bone union and maintain the femoral neck length and original tilt without nearby soft tissue or cartilage injury.

Incidence and Risk Factors of Short Axial Length of the Proximal Femur: A Caution in the Use of Femoral Neck System in Patients with Garden Type I/II Femoral Neck Fractures

BACKGROUND

In 2018, Femoral Neck System (FNS), a dedicated fixator for femoral neck fractures, was introduced. This device has been in increasing use because it provides excellent rotational and angular stability. However, the shortest bolt of FNS is 75 mm long. Thus, it is not usable when the axial length of the proximal femur (ALPF), the distance between the innominate tubercle and the surface of the femoral head, is less than 80 mm. In this study, we investigated the incidence and associated factors of small ALPF (< 80 mm) in femoral neck fracture patients.

METHODS

We measured the ALPF on preoperative computed tomography (CT) scans of 261 patients (166 women and 55 men), who were operated due to nondisplaced or impacted femoral neck fractures. The ALPF was measured on reconstructed oblique coronal images along the femoral neck. We evaluated the distribution of ALPF, calculated the incidence of small ALPF (< 80 mm), and correlated it with patient's height, weight, body mass index, age, bone mineral density (T-score), and caput-column-diaphysis angle.

RESULTS

The ALPF ranged from 67.4 mm to 107.1 mm (mean, 88.4 mm; standard deviation, 7.2 mm). In 19 patients (8.6%, 19 / 221), the length was < 80 mm. The ALPF was strongly correlated with height (correlation coefficient = 0.707, R2 = 0.500, p < 0.001) and moderately correlated with weight (correlation coefficient = 0.551, R2 = 0.304, p < 0.001). The T-score was moderately correlated with the ALPF (correlation coefficient = 0.433, R2 = 0.187, p < 0.001). The age was moderately correlated with the ALPF (correlation coefficient =-0.353, R2 = 0.123, p < 0.001).

CONCLUSIONS

A considerable percentage of femoral neck fracture patients (8.6%) had small proximal femurs (ALPF < 80 mm), which cannot be operated with FNS. We recommend measuring the ALPF using reconstructed oblique coronal CT images or scaled hip radiographs: en face view of the femoral neck prior to surgery in patients with short stature and/or low body weight. If the ALPF is < 80 mm, the surgeon should prepare other fixation devices.

Reliability of the Garden Alignment Index and Valgus Tilt Measurement for Nondisplaced Femoral Neck Fractures

Anteroposterior (AP) alignment assessment for nondisplaced femoral neck fractures is important for determining the treatment strategy and predicting postoperative outcomes. AP alignment is generally measured using the Garden alignment index (GAI). However, its reliability remains unknown. We compared the reliability of GAI and a new AP alignment measurement (valgus tilt measurement [VTM]) using preoperative AP radiographs of nondisplaced femoral neck fractures. The study was designed as an intra- and inter-rater reliability analysis. The raters were four trauma surgeons who assessed 50 images twice. The main outcome was the intraclass correlation coefficient (ICC). To calculate intra- and inter-rater reliability, we used a mixed-effects model considering rater, patient, and time. The overall ICC (95% CI) of GAI and VTM for intra-rater reliability was 0.92 (0.89−0.94) and 0.86 (0.82−0.89), respectively. The overall ICC of GAI and VTM for inter-rater reliability was 0.92 (0.89−0.95), and 0.85 (0.81−0.88), respectively. The intra- and inter-rater reliability of GAI was higher in patients aged <80 years than in patients aged ≥80 years. Our results showed that GAI is a more reliable measurement method than VTM, although both are reliable. Variations in patient age should be considered in GAI measurements.

The incidence of focal osteonecrosis of the femoral head and its impact on conversion hip arthroplasty after screw fixation of femoral neck fractures: a multicenter retrospective study based on postoperative magnetic resonance imaging

PURPOSE

Osteonecrosis of the femoral head (ONFH) and subsequent head collapse is a major concern after internal fixation of femoral neck fracture (FNF). Previous studies focused on ONFH incidence using plain radiography; postoperative magnetic resonance imaging (MRI) was rarely performed. We performed a multicenter retrospective study to investigate the incidence of ONFH and the need for conversion hip arthroplasty after FNF screw fixation.

METHODS

We reviewed 195 patients who underwent screw fixation during closed FNF reduction between 2012 and 2017 at three institutions. Except for patients who did not consent to MRI, all patients underwent postoperative MRI either 1-3 years after screw fixation. The occurrence of ONFH was investigated through plain radiography and MRI.

RESULTS

Thirty patients were diagnosed with ONFH through plain radiography, and an additional 33 patients were diagnosed with MRI, resulting in a total of 63 patients (32.3%) diagnosed with ONFH. The mean time to ONFH diagnosis was 18.9 months and the conversion rate to hip arthroplasty was 10.2%. Of the 33 patients who were normal on hip radiography but exhibited ONFH on MRI, all had small focal lesions not associated with head collapse at the last follow-up. The ONFH group diagnosed through plain radiography had more unstable FNFs than the group diagnosed through MRI.

CONCLUSION

Although postoperative MRI revealed a higher incidence of ONFH after FNF screw fixation than reported previously, the small focal MRI lesions were not associated with increased risks of femoral head collapse or conversion to arthroplasty.

"In-Out-In" Percutaneous Reduction Technique for Treatment of Valgus-Impacted Femoral Neck Fractures: A Technical Trick and Case Series

OBJECTIVE

Valgus-impacted femoral neck fractures with or without posterior tilt of the femoral head are very common and full of pitfalls in clinical practice, which may lead to femoral neck shortening (FNS) and avascular necrosis (AVN). The study tries to introduce a novel technical trick aiming at anatomical reduction of valgus-impacted femoral neck fracture with minimally invasive procedure, and summarize the clinical prognosis in case series.

METHODS

In this retrospective study, 24 patients (seven men and 17 women) with valgus-impacted femoral neck fractures between May 2017 and July 2020 were managed by "in-out-in" percutaneous reduction technique (percutaneous reduction group). Another 24 cases (10 men and 14 women) suffering the fractures underwent in situ fixation were enrolled as control group for function comparison (in situ fixation group). All patients were followed up for 24-42 months. The clinical outcomes included complications after operations (χ² test) and Harris Hip Score (HHS) for hip function (unpaired t test) in the two groups. The radiographic outcomes were evaluated by collodiaphyseal angle, posterior tilt angle, and FNS before the operation and during the follow-up in the percutaneous reduction group (unpaired t test).

RESULTS

Patients' preoperative data, including age, sex, affected side, fracture types, and medical history, were similar between the two groups, respectively (p > 0.05). After surgery, the mean HHS at 6, 12, and 24 months were all better in the percutaneous reduction group (76 ± 6.72, 85.34 ± 6.33 and 90.54 ± 5.81) than that in the in situ fixation group (70.86 ± 6.91, 80 ± 6.11 and 84.1 ± 7.82), respectively (p < 0.05). One patient suffered fixation failure with screws retreat and one patient suffered AVN in the percutaneous reduction group. In the in situ fixation group, AVN occurred in two patients at last follow-up. There was no significant difference in complication amounts between the two groups (p > 0.05). In the percutaneous reduction group, collodiaphyseal angle, posterior tilt angle, and amount of FNS were significantly different between preoperative cases and immediately postoperative cases (p < 0.05). However, there was no statistical difference of the measurements among postoperative cases at different time points (within 24 h, 6 months, and 2 years postoperatively) (p > 0.05).

CONCLUSIONS

Our experience of the technique and the case series show that "in-out-in" percutaneous reduction technique for treatment of valgus-impacted femoral neck fracture with or without posterior tilt of the femoral head is safe and effective for achieving successful bone union and satisfactory function.

Internal Fixation of Garden Type III Femoral Neck Fractures with Sliding Hip Screw and Anti-Rotation Screw: Does Increased Valgus Improve Healing?

Background and Objectives: The aim of this study was to compare the effect of valgus versus anatomic reduction on internal fixation of Garden type III femoral neck fractures using the sliding hip screw (SHS) and anti-rotation screw (ARS) regarding the radiographic and therapeutic outcome. Patients and Methods: A retrospective case-controlled study was performed in a level I trauma center. All patients between 2006 and 2020 aged younger than 70 years with a Garden type III femoral neck fracture and a Kellgren-Lawrence score under grade III stabilized using SHS and ARS were identified. One-hundred and nine patients were included, with a group distribution of sixty-eight patients in group A (anatomic reduction) and forty-one patients in group B (valgus reduction). Results: Mean age was 55 years, and the mean Kellgren-Lawrence score was 1 in both groups. Mean femoral neck angle was 130.5 ± 3.8° in group A and 142.8 ± 4.3° in group B (p = 0.001), with an over-correction of 12° in group B. Tip-apex distance was 10.0 ± 2.8 mm in group A versus 9.3 ± 2.8 mm in group B (p = 0.89). Healing time was 9 weeks in group A compared to 12 weeks in group B (p = 0.001). Failure rate was 4.4% in group A and 17.1% in group B (p = 0.027). Conclusions: Anatomic reduction of Garden type III femoral neck fractures in patients younger than 70 years treated using SHS and ARS resulted in significantly lower failure rates and shorter healing times than after valgus reduction. Therefore, it can be recommended to achieve anatomic reduction.

The Risk of Avascular Necrosis Following the Stabilization of Femoral Neck Fractures: A Systematic Review and Meta-Analysis

Background: Avascular necrosis (AVN) of the femoral head often requires surgical treatment and is often associated with femoral neck fractures. We conducted a systematic review and meta-analysis of recent research on the risk of AVN following the stabilization of fractured femoral neck with implants in PubMed. We assessed the effect of age on AVN incidence among patients aged > 50 and younger, depending on fracture type, Garden stage, Pouwels degree, Delbet stage, and age category. We followed PRISMA guidelines. Relevant studies were defined as research articles describing real-world studies reporting on the risk of AVN following primary surgical fracture stabilization with implants, published between 1 January 2011 and 22 April 2021. Fifty-two papers met the inclusion criteria, with a total of N = 5930 with surgically managed fractures. The pooled mean AVN incidence was significantly higher among patients with displaced fractures (20.7%; 95% CI: 12.8−28.5%) vs. those with undisplaced fractures (4.7%; 95% CI: 3.4−6.0%). No significant correlation was observed between AVN incidence weighted by sample size and time interval from injury to surgery (p = 0.843, R2 = 0.01). In conclusion, the risk of AVN following femoral neck fractures was generally high, especially in patients with displaced fractures. The time from injury to surgery did not correlate with AVN incidence.

[Comparison of femoral neck system and inverted triangle cannulated screws fixations in treatment of Pauwels typle femoral neck fractures]

Objective

To compare the effectiveness of the femoral neck system (FNS) and inverted triangle cannulated screws (ITCS) for the treatment of Pauwels type Ⅲ femoral neck fractures.

Methods

The clinical data of 59 patients with Pauwels type Ⅲ femoral neck fractures treated between May 2019 and November 2020 were retrospectively analysed. The patients were divided into FNS group (28 cases) and ITCS group (31 cases) according to the different internal fixation. There was no significant difference in gender, age, affected side, body mass index, cause of injury, smoking history, alcohol abuse history, Pauwels angle, Garden classification, AO/Orthopaedic Trauma Association (AO/OTA) classification, and time from injury to operation between the two groups ( P>0.05). The operation time, incision length, intraoperative blood loss, extra assisted reduction procedures (Kirschner wire prying reduction or open reduction), hospitalization stay, and early complications were recorded and compared between the two groups. Garden index and Haidukewych score were used to evaluate fracture reduction. Fracture healing time, lateral thigh irritation, time of partial or total weight-bearing postoperatively, shortening length and degree of femoral neck, change of caput-collum-diaphysis (CCD) angle (the difference of CCD angle between immediate after operation and last follow-up), incidence of osteonecrosis of femoral head and revision surgery were recorded and compared between the two groups. Hip joint function were evaluated by Harris score.

Results

The operation time of FNS group was significantly shorter than ITCS group, and the incision length was significantly longer than ITCS group ( P<0.05). There was no significant difference in intraoperative blood loss, assisted reduction, Garden index, Haidukewych score, and hospitalization stay between the two groups ( P>0.05). All the incisions healed by first intention. There were 2 deep vein thrombosis in the FNS group and 1 pulmonary infection and 1 deep vein thrombosis in the ITCS group. No significant difference was found in the incidence of early postoperative complications (7.1% vs. 6.5%) between the two groups ( P=1.000). Patients in both groups were followed up 3-14 months, and there was no significant difference in follow-up time between the two groups ( t=-0.553, P=0.582). The fracture healing time, Harris score, and the partial weight-bearing time after operation of the FNS group were significantly better than those of the ITCS group ( P<0.05). However, there was no significant difference in total weight-bearing time between the two groups ( Z=-1.298, P=0.194). No lateral thigh irritation was found in the FNS group, while 10 patients in the ITCS group had lateral thigh irritation, and the incidence between the two groups (0 vs. 32.3%) was significant ( P=0.001). At last follow-up, the shortening length and degree of femoral neck and the change of CCD angle in FNS group were significantly less than those in ITCS group ( P<0.05). There was no patient with osteonecrosis of femoral head or reoperation in the FNS group, while 4 patients in the ITCS group underwent reoperation (including 2 cases of osteonecrosis of the femoral head). However, the incidences (0 vs. 6.5%; 0 vs.12.9%) between the two groups were not significant ( P=0.493; P=0.114).

Conclusion

Using FNS to treat Pauwels type Ⅲ femoral neck fracture is simple as well as able to reduce the shortening of the femoral neck and the change of the CCD angle. Also, FNS is conducive to the recovery of hip joint function, which should be considered as a new choice for the treatment of young femoral neck fracture patients.

The Effect on the Fracture Healing following Femoral Neck Shortening after Osteoporotic Femoral Neck Fracture Treated with Internal Fixation: Finite Element Analysis

Objective

To evaluate the stress status of fracture site caused by femoral neck shortening and to analyze the stress of fracture site and the implants from the finite element point of view.

Methods

CT scan data of hip of a normal adult female were collected. Three-dimensional reconstruction MICs and related module function simulation was used to establish the postoperative shortening model of femoral neck fracture with Pauwels angle > 50°, which was treated with cannulated screws. The models were divided into four groups: normal femoral neck, shortening in 2.5 mm, shortening in 7.5 mm, and shortening in 12.5 mm. The finite element analysis software msc.nastran2012 was used, and the data of maximum stress and stress nephogram of fracture site and implants were carried out.

Results

From normal femoral neck to shortening in 12.5 mm of the femoral neck, the maximum tensile stress increased gradually in the fracture site above the cannulated screws while compressive stress decreased gradually in the fracture site below the cannulated screws, and the maximum stress of the cannulated screws increased gradually with obvious stress concentration at the screw holes in the fracture site, and the peak value of stress concentration was about 179 MPa.

Conclusion

The biomechanical environment of the fracture site changed by femoral neck shortening. With the increasing of femoral neck shortening, the stress of the fracture site and implants would be uneven; then, the stability of fracture site would become worse, and the possibility of implant sliding or even breakage would be increased.

Anterior positioning screw in proximal femoral plating restricts posterior tilt of retroverted femoral neck fractures: a retrospective cohort study

Background

Preoperative posterior tilt is a risk factor for fixation failure in femoral neck fractures. This study aimed to evaluate the configuration of anterior positioning screw in proximal femoral plating in the treatment of retroverted femoral neck fractures in terms of resisting posterior tilt.

Methods

We retrospectively analyzed patients with retroverted femoral neck fractures who were fixed by proximal femoral plating from January 2014 to August 2019. All patients were divided into two groups according to screw configuration: anterior long-threaded screw (ALTS, n = 36) and normally short-threaded screws (NTS, n = 46). Baseline characteristics were reviewed and radiological and clinical outcomes were analyzed. Logistic regression analysis was used to identify risk factors for developing posterior tilt.

Results

Age, gender, Garden classification, posterior comminution, and reduction quality showed no significant difference between the groups. Increased posterior tilt was lower in the ALTS group (3.2°, 2.1–4.3°) than that in the NTS group (5.3°, 4.2–8.3°) (p < 0.001), and the percentage of people with > 5° of posterior tilt was also lower in the ALTS group (5, 13.9% vs. 24, 52.2%; p < 0.001). Femoral neck shortening (FNS) was lower in the ALTS group (3.1 (2.1–4.7) mm vs. 4.3 (3.1–6.3) mm, p = 0.003), though not statistically significant when using 5 mm as the cut-off value. Harris Hip Score in the ALTS group was higher than that in the NTS group (87.0, 84.0–90.0 vs. 82.0, 76.0–84.5; p < 0.001). Postoperative complications including delayed union, nonunion, and avascular necrosis were comparable between the groups. Multivariable analysis identified posterior comminution (OR 15.9, 95% CI 3.6–70.3, p < 0.001), suboptimal reduction quality (OR 12.0, 95% CI 2.6–56.1, p = 0.002), and NTS configuration (reference: ALTS configuration) (OR 21.9, 95% CI 4.1–116.4, p < 0.001) as risk factors for developing posterior tilt.

Conclusions

Configuration of anterior positioning screw in proximal femoral plating provides better resistance against posterior tilt in the fixation of retroverted femoral neck fractures. Also, posterior comminution, suboptimal reduction, and NTS configuration (reference: ALTS) are risk factors for developing posterior tilt.

Trial registration

The trial registration number was ChiCTR2000039482.