A sophisticated fracture classification system of the proximal femur trochanteric region (AO/OTA-31A) based on 3D-CT images

[Morphological characteristics and reduction techniques of sagittal beak-like deformity of head-neck fragment in femoral intertrochanteric fractures]

Objective

To summarize the morphological characteristics of sagittal beak-like deformity of head-neck fragment in femoral intertrochanteric fractures and to investigate the technical skills in fracture reduction.

Methods

A clinical data of 31 patients with femoral intertrochanteric fractures between May 2021 and April 2023 was retrospectively analyzed. The fractures had sagittal beak-like deformity of head-neck fragment in all patients. There were 13 males and 18 females, with an average age of 76.2 years (range, 68-83 years). The time from injury to operation was 36-76 hours (mean, 51.2 hours). Fractures were classified as type A1.2 in 10 cases, type A1.3 in 11 cases, type A2.2 in 6 cases, and type A2.3 in 4 cases according to the AO/Orthopaedic Trauma Association (AO/OTA)-2018 classification; and as type A1.3 in 10 cases, type A2.1 in 11 cases, type A2.2 in 6 cases, type A2.3 in 2 cases, and type A2.4 in 2 cases according to a novel comprehensive classification for femoral intertrochanteric fractures proposed by the "Elderly Hip Fracture" Research Group of the Reparative and Reconstructive Surgery Committee of the Chinese Rehabilitation Medical Association. Based on preoperative X-ray films, CT scan and three-dimensional reconstruction, the fractures were classified into two types: type 1 (14 cases), with uncomplicated fracture morphology, severe bone interlocking and (or) soft tissue incarceration; type 2 (17 cases), with severe fracture crushing, obvious dissociation between bone blocks, and severe soft tissue hinge destruction. After the failure of the closed reduction, all patients underwent fracture reduction assisted with instrument via anterior minimal incision and proximal femoral nail antirotation nails internal fixation. The operation time, intraoperative fluoroscopy, intraoperative visible blood loss, length of hospital stay, and incidence of complications were recorded. The fracture reduction quality and stability score were assessed at immediate after operation under fluoroscopy. The fracture healing was evaluated and healing time was recorded by X-ray films. The pain visual analogue scale (VAS) score was performed at 48 hours after operation and Parker-Palmer activity score at 3 months after operation for function evaluation.

Results

The operation time was 39-58 minutes (mean, 46.3 minutes); fluoroscopy was performed 13-38 times (mean, 23.5 times) during operation; the intraoperative visible blood loss was 45-90 mL (mean, 65.3 mL). The fracture reduction quality and stability score were rated as good in 29 cases and acceptable in 2 cases. The pain VAS score was 2-6 (mean, 3.1) at 48 hours after operation. Eleven patients developed deep vein thrombosis of the lower limbs after operation. Patients were hospitalized for 6-10 days (mean, 7.3 days). All patients were followed up 5-8 months (mean, 6.5 months). All fractures healed at 3.5-8.0 months after operation (mean, 4.5 months). Parker-Palmer activity score at 3 months after operation was 9 in 28 cases and 6 in 3 cases.

Conclusion

The femoral intertrochanteric fracture with sagittal beak-like deformity of head-neck fragment is difficult to manually reduce. The pin combined with cannulated screw insertion to the neck cortex can hold the fragment and assist fracture reduction, which is a simple and effective technique.

Role of Anteromedial Cortical Support for Unstable Intertrochanteric Fractures Being Treated With Cephalomedullary Nails

INTRODUCTION

Reduction quality is of paramount importance for an optimal outcome in unstable pertrochanteric fractures. The non-anatomical functional anteromedial buttress is proposed to prevent impending mechanical complications. We aimed to evaluate the role of anteromedial cortical support in preventing mechanical complications following fixation with the cephalomedullary nail.

MATERIALS AND METHODS

A prospective, single-arm interventional study was conducted in the Orthopaedics Department of a Combined Military Hospital (CMH) in Rawalpindi. The duration of the study was 24 months. Patients were recruited by the purposive sampling technique as per inclusion/exclusion criteria. Preoperatively, the reduction was categorized as per Baumgartner's and Chang's criteria. Post-operatively, weight bearing as tolerated was advised. Radiographs prior to discharge for loss of reduction were evaluated. Follow-up radiographic measurements of neck length, neck shaft angle, and their loss as per protocol were done at three and six months.

RESULTS

A total of 202 patients were operated on from October 21 until August 23. Mortality at six months in 39 patients (19.3%) and loss to follow-up in 31 patients (15.3%) resulted in 132 patients with complete follow-up and having developed complications in 12 patients (9.09%). The mean age was 76.3 ± 7.98 years; males were 105 (79.5%), and females were 27 (20.5%). Closed reduction was 58 (43.9%), and additional manoeuvres were required in 74 (56.1%). The mean tip apex distance (TAD) was 24.56 ± 2.76, and the Calcar gap was 5.16 ± 1.27. Cleveland zone centre-centre in 54 (40.9%), inferior-centre in 65 (49.2%), and inferior-posterior (9.9%) were statistically significant for mechanical complications (p≤0.001). There was a significant association between the grading of Chang's and Baumgartner's poor groups for the development of mechanical complications (p≤0.001). The mean time to full weight bearing without support was 21 ± 1.22 weeks. The mean Hip Harris score at six months was 69.27 ± 7.68.

CONCLUSION

Results suggest that anteromedial cortical support can lead to fewer potential mechanical complications at six months. A higher Chang's grade drives surgeons to engage in additional manoeuvres. Anteromedial cortical support is worth consideration for unstable pertrochanteric fractures.

[Research progress on distal interlocking screws of cephalomedullary nails in intertrochanteric fractures]

Objective

To summarize the new research progress in distal interlocking screws of cephalomedullary nails for the treatment of intertrochanteric fractures.

Methods

Relevant domestic and foreign literature was extensively reviewed to summarize the static/dynamic types of distal interlocking screw holes, biomechanical studies, clinical studies and application principles, effects on toggling in the cavity, and related complications of distal interlocking screws.

Results

The mode of the distal interlocking screw holes can be divided into static and dynamic. Distal interlocking screws play the role of anti-rotation, maintaining femur length, resisting compression stress, increasing torque stiffness, resisting varus stress, etc. The number of the screws directly affects the toggling of the main nail in the cavity. At present, regardless of whether long or short nails are used, distal interlocking screws are routinely inserted in clinical practice. However, using distal interlocking screws can significantly increase the duration of anesthesia and operation, increase fluoroscopy exposure time, surgical blood loss, and incision length. There is a trend of trying not to use distal interlocking screws in recent years. No significant difference is found in some studies between the effectiveness of dynamic and static interlocking for AO/Orthopaedic Trauma Association (AO/OTA) 31-A1/2 fractures. At present, the selection of the number and mode of distal interlocking screws is still controversial. When inserting distal interlocking screws, orthopedists should endeavor to minimize the occurrence of complications concerning miss shot, vascular injuries, local stress stimulation, and peri-implant fractures.

Conclusion

Distal interlocking screws are mainly used to prevent rotation. For stable fractures with intact lateral walls, long cephalomedullary nails can be used without distal interlocking screws. For any type of intertrochanteric fractures, distal interlocking screws are required when using short cephalomedullary nails for fixation. Different interlocking modes, the number of interlocking screws, and the application prospects of absorbable interlocking screws may be future research directions.

Finite element analysis of the effect of residual lateral wall volume on postoperative stability in intertrochanteric fractures

BACKGROUND

Lateral wall fractures represent crucial risk factors for postoperative internal fixation failure in intertrochanteric femoral fractures. However, no consensus exists on the type of lateral wall fracture requiring interventional management. This study aimed to investigate the effect of residual lateral wall volume on the postoperative stability of intertrochanteric femur fractures with associated lateral wall fractures, providing valuable reference for the clinical management of the lateral wall.

METHODS

Eleven bone defect models of intertrochanteric femur fractures with varying residual lateral wall volumes were constructed using finite element analysis. These models were fixed with proximal femoral nail antirotation (PFNA). Simulations of von Mises stress and displacement distribution of the PFNA and femur during normal walking were conducted. Statistical analysis was performed to assess the correlation between volume and the maximum von Mises stresses and displacements of the PFNA and femur.

RESULTS

In all 11 models, the maximum von Mises stress and displacement of the helical blade, intramedullary nail, and femur occurred at the same locations. As residual lateral wall volume increased, the maximum von Mises stress and displacement of the helical blade, intramedullary nail, and maximum femoral displacement gradually decreased. However, the overall trend of the maximum femoral von Mises stress gradually decreased. At 70% retention of the residual lateral wall volume, there was a more pronounced change in the value of the maximum stress change of the helical blade and the intramedullary nail. Statistical analysis, including the Shapiro-Wilk test and Pearson correlation analysis, demonstrated a significant negative correlation between volume and the maximum von Mises stress and displacement of the helical blade, intramedullary nail, and femur. Linear regression analysis further confirmed this significant negative correlation.

CONCLUSION

Finite element analysis of the residual lateral wall revealed a significant correlation between volume and the postoperative stability of intertrochanteric femur fractures. A volume of 70% may serve as the threshold for stabilizing the residual lateral wall. Volume emerges as a novel index for evaluating the strength of the residual lateral walls.

The remnant axial cortical length of the proximal femur in pertrochanteric fractures: a three-dimensional computed tomography study and its clinical implications

BACKGROUND

Cortical buttress are important factors for postoperative stable reconstruction of per/inter-trochanteric fractures. The study aimed to measure the remnant axial cortical length (RACL) of the proximal circumference of the femur, and to determine which part of the RACL can be used reliably to postoperatively sustain the head-neck fragment as a cortical support pattern.

METHODS

Eighty patients with trochanteric hip fractures admitted from January 2015 to January 2016 were included in a retrospective study. Their pre-operative computed tomography (CT) images were used to form 3D-CT reconstructions via Mimics software. After simulated rotation and movement for fracture reduction, the RACL, its three component parts-namely, the remnant anterior cortex (RAC), remnant lateral cortex (RLC), and remnant posterior cortex (RPC) -the γ angle between the anterior and posterior cortex, and the Hsu's lateral wall thickness (LWT) were evaluated.

RESULTS

Patients with an A1 fracture (21/80) had a longer RACL (88.8 ± 15.8 mm) than those with an A2 fracture (60.0 ± 11.9 mm; P < 0.01). The RAC, RLC, and RPC of the RACL in A1 fractures were also significantly longer than those in A2 fractures (P < 0.001). However, the most significant difference among the three components of the RACL was in the RPC, which was 27.3 ± 7.8 mm in A1 fractures and 9.2 ± 6.6 mm in A2 fractures. In addition, the coefficient of variation of the RAC was only 20.0%, while that of the RPC was 75.5%. The average γ angle in A1 fractures was 16.2 ± 13.1°, which was significantly smaller than that in A2 fractures, which was 40.3 ± 14.5° (P < 0.001). There was a significant statistical difference in the LWT between A1 and A2 fractures (P < 0.001). There were significant differences in the RACL, RAC, RLC, RPC, γ angle, and LWT among the five subtypes (P < 0.001).

CONCLUSIONS

The RAC is relatively stable in pertrochanteric fractures. Fracture reduction through a RAC buttress may help to enhance the postoperative stable reconstruction of per/inter-trochanteric fractures and make possible good mechanical support for fracture healing.

Traction images heavily influence lateral wall measurement in trochanteric hip fractures. A prospective study

INTRODUCTION

hip fracture represents a global health problem, with a high morbidity and mortality rate and an increasing incidence. The treatment of trochanteric fractures is reduction and osteosynthesis, and implant selection depends mainly on the stability of the fracture and lateral wall competence. Lateral wall competence has gained relevance in recent years, which led to the modification of the AO/OTA classification. However, determination of lateral wall integrity is difficult from plain radiographs; the influence of images with traction on its measurement has not been evaluated.

METHODS

prospective concordance study, emergency and post-traction radiographs of 65 patients with trochanteric fracture were evaluated by six orthopedic surgeons independently, measuring the lateral wall, classifying the fracture according to the AO/OTA 2018 classification and selecting the implant for osteosynthesis. A comparison of incompetent to intact lateral wall proportion between each image set was made. Secondary outcomes were the inter-observer correlation of lateral wall measurement and inter-observer agreement of classification and implant choice.

RESULTS

the proportion of patients with an incompetent lateral wall in emergency x-ray was 37.43% (CI 95% 0.326-0.422), while the proportion in post-traction fluoroscopy was 15% (CI 95% 0.115-0.185), with a statistically significant difference (p < 0.001). 40.1% of patients with an incompetent lateral wall changed to an intact one. Inter-observer correlation for the lateral wall thickness was 0.399 (CI 95% 0.292-0.519) in emergency x-ray and 0.658 (CI 95% 0.564-0.748) in post-traction fluoroscopy, with a substantial agreement. Inter-observer agreement for the fracture classification was fair to moderate using emergency x-ray (κ 0.369 95%CI 0.330-0.408) and fair to moderate with post-traction fluoroscopy (κ 0.400, 95% CI 0.334-0.466).

CONCLUSION

traction images significantly change the measurement of the lateral wall in trochanteric fractures, changing from an incompetent to a competent wall in 40% of patients. The correct classification of trochanteric fractures is crucial to make the best decision when deciding which implant to use, and the measurement of the lateral wall is determinant in the actual AO/OTA classification. Therefore, traction images appear as necessary for correct decision-making.

Residual lateral wall width predicts a high risk of mechanical complications in cephalomedullary nail fixation of intertrochanteric fractures: a retrospective cohort study with propensity score matching

PURPOSE

The purpose of this study is to determine whether the integrity of the entry portal of head-neck implant is related to postoperative mechanical complications.

METHODS

We retrospectively reviewed consecutive patients with pertrochanteric fractures in our hospital treated from January 1, 2018, to September 1, 2021. Based on the integrity of the entry portal for head-neck implants on the femoral lateral wall, patients were divided into two groups, including the ruptured entry portal (REP) group and the intact entry portal (IEP) group. After 4:1 propensity score-matched analyses were used to balance the baseline of the two groups, a total of 55 patients were extracted from the original participants, including 11 patients in the REP group and 44 matched patients in the IEP group. The anterior to posterior cortex width on the mid-level of the lesser trochanter was measured and defined as the residual lateral wall width (RLWW).

RESULTS

Compared with the IEP group, the REP group was correlated with postoperative mechanical complications (OR = 12.00, 95% CI 1.837-78.369, P = 0.002) and hip-thigh pain (OR = 26.67, 95% CI 4.98-142.86). RLWW ≤ 18.55 mm indicated a high likelihood (tau-y = 0.583, P = 0.000) of becoming the REP type postoperatively and being more likely to suffer from mechanical complications (OR = 30.67, 95% CI 3.91-240.70, P = 0.000) and hip-thigh pain (OR = 14.64, 95% CI 2.36-90.85, P = 0.001).

CONCLUSION

Rupture of entry portal is a high-risk factor for mechanical complications in intertrochanteric fractures. RLWW ≤ 18.55 mm is a reliable predictor of the postoperative REP type.

Proposal and validation of a new classification for trochanteric fractures based on medial buttress and lateral cortical integrity

Background

Trochanteric fractures usually require surgical treatment. The currently used classification system, such as AO classification, cannot cover all variant types, and is poor in reliability, causing confusion in surgical decision making. This study describes a simple, well-covered, re-liable, accurate, and clinically useful classification.

Methods

We retrospectively reviewed the records of 907 patients with trochanteric fractures treated by us from 1,999 to 2019 and proposed a new classification according to radiographs. Then, 50 records randomly selected in proportion were examined by 10 observers (5 experienced and 5 inexperienced) independently according to AO and the new classification. After a 2-week interval, repeat evaluation was completed. The Kappa coefficient was used to investigate the intra-observer reliability, inter-observer reliability and the agreement between the observers and the "reference standard".

Results

The new classification system includes 12 types composed of 3 medial groups and 4 lateral groups. According to the medial buttress, the fractures are divided into group I (intact lesser trochanter, adequate but-tress), group II (incomplete lesser trochanter, effective cortical buttress after reduction) and group III (huge defect of the medial cortex). According to the penetration region of the lateral fracture line, the fractures are divided into group A (intact lateral cortex), group B (incomplete lateral cortex), group C (subtrochanteric fractures) and group D (multiple lateral fracture lines). All of the included cases can be classified according to the new classification, of which 34 (3.75%) cases are unclassifiable by the AO classification. Intra-observer: The experienced achieved substantial agreement using both AO [k = 0.61 (95% confidence interval 0.46-0.76)] and new classification [k = 0.65 (0.55-0.76)]. The inexperienced reached moderate agreement using both AO [k = 0.48 (0.33-0.62)] and new classification [k = 0.60 (0.50-0.71)]. Inter-observer: The overall reliabilities for AO [k = 0.51 (0.49-0.53)] and for new classification [k = 0.57 (0.55-0.58)] were both moderate. The agreement between the experienced and the reference standard according to AO [k = 0.61 (0.49-0.74)] and new classification [k = 0.63 (0.54-0.72)] were both substantial. The agreement between the inexperienced and the reference standard according to AO [k = 0.48 (0.45-0.50)] and the new classification [k = 0.48 (0.41-0.54)] were both moderate.

Conclusion

Compared with AO classification, our new classification is better in coverage, reliability and accuracy, and has the feasibility of clinical verification and promotion.