Trochanteric fragility fractures

Safety of Cement-augmented Femoral Cephalomedullary Nails: A Meta-analysis and Systematic Review

Trochanteric fractures of the femur pose an increasing burden for elderly people. The standard treatment for these types of fractures includes cephalomedullary nailing, which can be augmented with cement. Although many studies have reported on the stability of this augmented construct, few studies have examined its clinical benefit and safety. Therefore, the objective of this meta-analysis is to examine the perioperative complications and postoperative mortality associated with cement-augmented nails in the management of intertrochanteric and pertrochanteric fractures of the hip. A search of PubMed, Cochrane, and Google Scholar (pages 1-20) until January 2024 was conducted. Analysis of the outcomes included perioperative complications and postoperative mortality. Seven studies were included in this meta-analysis. Fewer perioperative complications were observed when using a cemented femoral nail (P=0.002), although there was no difference in postoperative mortality (P=0.30). This meta-analysis is the first to assess the safety of a cement-augmented femoral nail in management of intertrochanteric and pertrochanteric fractures. The results showed a reduced rate of perioperative complications, which may be attributed to a more a solid construct, which reduced the duration of postoperative immobilization as well as use of a proper augmentation technique, resulting in a reduced rate of cement-associated complications.

Proximal femoral fractures in the elderly. Does cement augmentation decrease mechanical failures and increase function? A retrospective cohort study

INTRODUCTION

The management of extracapsular proximal femoral fractures (EPFF) with intramedullary nails in the elderly is hindered by osteoporosis, leading to complications that significantly impact functionality due to restrictions for full weight-bearing. We hypothesized that cement augmentation of the cephalic blade could enhance the bone-implant interface and reduce mechanical failure, thereby improving patient functionality in the management of EPFF.

MATERIALS AND METHODS

A retrospective cohort study was conducted on patients ≥ 70 years old with type 31-A EPFF (AO/OTA classification) treated with intramedullary nailing between 2017 and 2021, with and without cephalic blade augmentation with bone cement. Evaluation included demographic, clinical/functional parameters, complications, mortality, and radiological assessment (tip-apex distance (TAD), position of the helical blade, cut-out, cut-through, and any fixation failure).

RESULTS

Fifty-eight patients were included, with 30 in the augmented group and 28 in the non-augmented group, with a median age of 88 and 86 years, respectively (p = 0.143), and a median follow-up of 17.9 and 18.2 months, respectively (p = 0.395). Both groups were comparable in terms of sex, Charlson Comorbidity Index, place of residence, pre-fracture mobility, and fracture stability. However, the non-augmented group showed worse ASA grade and pre-fracture cognitive status (p = 0.043). The most common position of the blade was center-center in both groups (96.7 % and 82.1 %, respectively) (p = 0.201). The mean TAD was 15.09 mm (±4.35) in the study group and 16.97 mm (±6.57) in the control group (p = 0.213). At one-year follow-up, there were no differences in medical complications (26.7 % and 28.6 %) (p = 1), surgical complications (6.7 % and 10.7 %) (p = 0.462), mortality (33.3 % and 21.4 %) (p = 0.385), or mechanical failure (0 % and 7.1 %) (p = 0.229). In the augmented group, one patient had intra-articular cement leak and implant infection, and a second patient presented avascular necrosis. In the non-augmented group, there was one periprosthetic fracture, one cut-out and one cut-through.

CONCLUSIONS

Cement augmentation in EPFF management does not improve functional outcomes or reduce mechanical complications. Furthermore, augmentation did not affect fracture reduction or the position of the helical blade in the head, nor was it associated with an increase in medical complications. However, augmentation can be considered a safe technique.

LEVEL OF EVIDENCE

Level IV.

Comparative study of a novel proximal femoral bionic nail and three conventional cephalomedullary nails for reverse obliquity intertrochanteric fractures: a finite element analysis

Purpose

Conventional cephalomedullary nails (CMNs) are commonly employed for internal fixation in the treatment of reverse obliquity intertrochanteric (ROI) fractures. However, the limited effectiveness of conventional CMNs in addressing ROI fractures results in significant implant-related complications. To address challenges associated with internal fixation, a novel Proximal Femoral Bionic Nail (PFBN) has been developed.

Methods

In this study, a finite element model was constructed using a normal femoral specimen, and biomechanical verification was conducted using the GOM non-contact optical strain measurement system. Four intramedullary fixation approaches-PFBN, Proximal Femoral Nail Antirotation InterTan nail (ITN), and Gamma nail (Gamma nail)-were employed to address three variations of ROI fractures (AO/OTA 31-A3). The biomechanical stability of the implant models was evaluated through the calculation of the von Mises stress contact pressure and displacement.

Results

Compared to conventional CMNs, the PFBN group demonstrated a 9.36%-59.32% reduction in the maximum VMS at the implant. The A3.3 ROI fracture (75% bone density) was the most unstable type of fracture. In comparison to conventional CMNs, PFBN demonstrated more stable data, including VMS values (implant: 506.33 MPa, proximal fracture fragment: 34.41 MPa), contact pressure (13.28 MPa), and displacement (17.59 mm).

Conclusion

Compared to the PFNA, ITN, and GN, the PFBN exhibits improvements in stress concentration, stress conduction, and overall model stability in ROI fractures. The double triangle structure aligns better with the tissue structure and biomechanical properties of the proximal femur. Consequently, the PFBN has significant potential as a new fixation strategy for the clinical treatment of ROI fractures.

Nail fixation of unstable trochanteric fractures with or without cement augmentation: A cost-utility analysis in the United States: Cost-utility of cement augmentation

OBJECTIVES

Recent clinical studies have shown favorable outcomes for cement augmentation for fixation of trochanteric fracture. We assessed the cost-utility of cement augmentation for fixation of closed unstable trochanteric fractures from the US payer's perspective.

METHODS

The cost-utility model comprised a decision tree to simulate clinical events over 1 year after the index fixation surgery, and a Markov model to extrapolate clinical events over patients' lifetime, using a cohort of 1,000 patients with demographic and clinical characteristics similar to that of a published randomized controlled trial (age ≥75 years, 83 % female). Model outputs were discounted costs, quality-adjusted life years (QALYs), and incremental cost-effectiveness ratio (ICER) over a lifetime. Deterministic and probabilistic sensitivity analyses were performed to assess the impact of parameter uncertainty on results.

RESULTS

Fixation with augmentation reduced per-patient costs by $754.8 and had similar per-patient QALYs, compared to fixation without augmentation, resulting in an ICER of -$130,765/QALY. The ICER was most sensitive to the utility of revision surgery, mortality risk ratio after the second revision surgery, mortality risk ratio after successful index surgery, and mortality rate in the decision tree model. The probability that fixation with augmentation was cost-effective compared with no augmentation was 63.4 %, 58.2 %, and 56.4 %, given a maximum acceptable ceiling ratio of $50,000, $100,000, and $150,000 per QALY gained, respectively.

CONCLUSION

Fixation with cement augmentation was the dominant strategy, driven mainly by reduced costs. These results may support surgeons in evidence-based clinical decision making and may be informative for policy makers regarding coverage and reimbursement.

Outcomes of cement augmentation in fragility trochanteric hip fractures - A multicenter randomized controlled trial follow-up

PURPOSE

Cement augmentation is considered to improve the bone-implant construct stability in hip fragility fractures, additionally biomechanical studies show that cement augmentation improves the pull-out strength and increases resistance to failure. Thus far, the advantage of these technique used in a clinical scenario is yet to be determined METHODS: a randomized, multicenter, single-blinded clinical trial was conducted in patients aged 65 years or older who were admitted to two level I trauma centers with a fragility intertrochanteric hip fracture during September 2015 and December 2017. Patients were stratified into 2 groups: patients between 65 and 85 years and older than 85 years. A balanced block randomization was performed using blocks of 6 patients: 3 patients assigned to the control group (no augmentation) and 3 patients to the intervention group. Follow-up visits were done at 1, 3, 6 and 12 postoperative months documenting the tip-apex distance (TAD) as well as followed up after 5 to 7 years of surgical procedure documenting EQ5D, Parker Mobility Score and mortality rates at these different time points.

RESULTS

A total of 90 patients were included but only 53 patients completed a one-year follow up. The mean immediate postoperative and one-year follow up TAD measurement from the whole cohort (20.99 mm vs 21.3 mm, respectively) showed no statistical significance (P = 0.18). For patients in the control group, the difference of TAD measurements from the immediate postoperative and one-year follow-up was -0.25 mm (P = 0.441). For patients included in the intervention group, the difference of TAD measurement from the immediate postoperative and 1-year follow up was -0.48 mm (P = 0.383). No statistical difference was found when stratified by age (p = 0.78). One patient from the control group had an implant failure after 1-month postoperative. Readmission after 30 days showed no statistical difference between both groups (7 vs. 7 patients, p = 0.754). Augmentation did not show a difference in most of the functional outcomes nor quality of life after 5 to 7 years of surgical procedure.

CONCLUSIONS

The use of augmentation can be considered a safe procedure for the fixation of fragility hip fractures.

Study protocol: biomechanical testing, finite element analysis and prospective, randomized, clinical study of single screw cephalomedullary nailing versus integrated dual interlocking screw fixation for unstable (31A21-3) intertrochanteric fractures in patients > 70 years old

BACKGROUND

Hip fractures are an increasingly common consequence of falls in older people that are associated with a high risk of death and reduced function. The vast majority of intertrochanteric fractures require surgical treatment to withstand early mobilization and weight bearing, which prevents complications due to prolonged bed rest and aids in fracture healing.

METHODS

This study is compromised by two parts, the experimental study and the clinical part. In the first part, a standard 130° nail will be used with the appropriate lag screw(s) and dynamic distal locking in synthetic osteoporotic femurs and the transmission of forces in the proximal femur, measured by a cortical surface-strain distribution, will be evaluated using digital image correlation. Finite element parametric models of the bone, the nails and their interface will be also developed. Finite element computations of surface strains in implanted femurs, after being validated against biomechanical testing measurements, will be used to assist the comparison of the nails by deriving important data on the developed stress and strain fields, which cannot be measured through biomechanical testing. In the other part, will set up a prospective, randomized, comparative clinical study among the Gamma3 and IT cephalomedullary nailing, in order to investigate if there are any statistical important differences in the main radiological measurements and functional status in closed unstable intertrochanteric fractures (A21-3) in patients aged over 70 years old at the 24-week follow-up evaluation using patient reported disease-specific outcomes.

DISCUSSION

This study will be the first to compare clinical, radiological and biomechanical measurements of the two different cephalomedullary nails. Our main hypothesis is that the IT nail would provide better radiological outcome and probably better clinical results than the Gama3 nail. Clinical trial registration International Standard Randomized Controlled Trial Number (ISRCTN): https://doi.org/10.1186/ISRCTN15588442 , registered on 19/4/2022.

Augmentation in fragility fractures, bone of contention: a systematic review

BACKGROUND

Osteoporosis is a complex multifactorial disease characterized by reduced bone mass and microarchitectural deterioration of bone tissue linked to an increase of fracture risk. Fragility fractures occur in osteoporotic subjects due to low-energy trauma. Osteoporotic patients are a challenge regarding the correct surgical planning, as it can include fixation augmentation techniques to reach a more stable anchorage of the implant, possibly lowering re-intervention rate and in-hospital stay.

METHODS

The PubMed database and the Google Scholar search engine were used to identify articles on all augmentation techniques and their association with fragility fractures until January 2022. In total, we selected 40 articles that included studies focusing on humerus, hip, spine, and tibia.

RESULTS

Literature review showed a quantity of materials that can be used for reconstruction of bone defects in fragility fractures in different anatomic locations, with good results over the stability and strength of the implant anchorage, when compared to non-augmented fractures.

CONCLUSION

Nowadays there are no recommendations and no consensus about the use of augmentation techniques in osteoporotic fractures. Our literature review points at implementing the use of bone augmentation techniques with a specific indication for elderly patients with comminuted fractures and poor bone quality.

Optimizing fixation methods for stable and unstable intertrochanteric hip fractures treated with sliding hip screw or cephalomedullary nailing: A comparative biomechanical and finite element analysis study

BACKGROUND

Despite recent advances in implants and surgical techniques, catastrophic and clinical failures in the treatment of intertrochanteric fractures continue to occur, with dire consequences in an overall frail population subset. The aim of the current study is to evaluate the effect of the factors under the surgeons' control, namely fracture reduction and implant selection, on the biomechanical behavior of fracture fixation constructs.

MATERIAL-METHODS

An experimental protocol was conducted with the use of instrumented sawbones, in order to validate the finite element models. The implants used were the Gamma3®and DHS systems. Subsequently, a series of scenaria were considered, including various reduction and implant angle combinations. Data were retrieved concerning the peak cancellous bone stresses around the hip screw and the volume of cancellous bone in the femoral head stressed at critical levels, as well as implant stresses and stresses on the cortical bone of the distal fragment.

RESULTS

All stable fracture models displayed significantly decreased cancellous bone stresses and implant stresses compared to their unstable counterparts, regardless of implant used. The effect of increasing implant angle led to a decrease in implant stresses in all models studied, but had a beneficial effect on the stresses in the cancellous bone of the proximal fragment only in the subgroups of stable fractures with both implants and unstable fractures treated with a cephalomedullary nail (CMN). In unstable fractures anatomically reduced, the use of CMN led to significantly lower peak stresses in the cancellous bone and a smaller volume of bone stressed at critical levels. Increasing the reduction angle by 5 ° led to a significant decrease in both peak stresses and volume of bone stressed at critical levels, more prominent in the sliding hip screw (SHS) models. Decreasing the reduction angle into varus by 5 or 10 ° led to a significant increase in bone and implant stresses regardless of implant used.

CONCLUSIONS

In stable two-part (AO31.A2) fractures the use of the SHS appears to be biomechanically equivalent to CMN. In unstable, anatomically reduced fractures, the use of CMN leads to significantly reduced cancellous bone stresses and decreased rotation of the proximal fragment during loading. A reduction in varus should be avoided at all costs. In unstable fractures treated with SHS a reduction in slight valgus appears to be biomechanically beneficial. The highest implant angle that allows for proper screw position and trajectory in the femoral head should be used for stable fractures with both implants and unstable fractures treated with Gamma3®.

Indications for cement augmentation in fixation of geriatric intertrochanteric femur fractures: a systematic review of evidence

INTRODUCTION

Achieving durable mechanical stability in geriatric intertrochanteric proximal femur fractures remains a challenge. Concomitant poor bone quality, unstable fracture patterns, and suboptimal reduction are additional risk factors for early mechanical failure. Cement augmentation of the proximal locking screw or blade is one proposed method to augment implant anchorage. The purpose of this review is to describe the biomechanical and clinical evidence for cement augmentation of geriatric intertrochanteric fractures, and to elaborate indications for cement augmentation.

METHODS

The PubMed database was searched for English language studies up to January 2021. Studies that assessed effect of calcium phosphate or methylmethacrylate cement augmentation during open reduction and internal fixation of intertrochanteric fractures were included. Studies with sample size < 5, nontraumatic or periprosthetic fractures, and nonunion or revision surgery were excluded. Study selection adhered to PRISMA criteria.

RESULTS

801 studies were identified, of which 40 met study criteria. 9 studies assessed effect of cement augmentation on fracture displacement. All but one found that cement decreased fracture displacement. 10 studies assessed effect of cement augmentation on total load or cycles to failure. All but one demonstrated that augmented implants increased this variable. Complication rates of cement augmentation during ORIF of intertrochanteric fractures ranged from 0 to 47%, while non-augmented implants ranged from 0 to 51%. Reoperation rates ranged from 0 to 11% in the cement-augmented group and 0 to 11% in the non-augmented group. Fixation failure ranged from 0 to 11% in the cement-augmented group and 0 to 20% in the non-augmented group. Nonunion ranged from 0 to 3.6% in the cement-augmented group and 0 to 34% in the non-augmented group.

CONCLUSIONS

Calcium phosphate or PMMA-augmented CMN fixation of IT fractures increased construct stability and improved outcomes in biomechanical and early clinical studies. The findings of these studies suggest an important role for cement augmentation in patient populations at high risk of mechanical failure.

Does augmentation increase the pull-out force of symphyseal screws? A biomechanical cadaver study

Purpose

Open reduction and internal fixation using anterior plate osteosynthesis currently represents the gold standard for the treatment of symphyseal disruptions. Since postoperative screw loosening with consequent implant failure is frequently observed, this study aims to evaluate if and to what extent augmentation can increase the pull-out force of symphyseal screws to improve the constructs stability.

Methods

Twelve human cadaveric anterior pelvic rings were separated at the symphyseal joint for bilateral testing, consequently achieving comparable sites. First, one non-augmented screw was drilled into the superior pubic ramus, whereas the contralateral side was primarily augmented. The screws were then withdrawn with a constant speed of 10 mm/min and the fixation strengths determined by the force (N) displacement (mm) curve. Finally, the primary non-augmented site was secondary augmented, representing revision surgery after initial implant failure, and the corresponding fixation strength was measured again.

Results

Augmentation compared to non-augmented screws displayed significantly higher pull-out forces with an increase in pull-out force by 377% for primary and 353% for secondary augmentation (p < 0.01). There was no significant difference in the pull-out force comparing primary and secondary augmentation (p = 0.74).

Conclusions

Primary and secondary augmentation significantly increases the stability of symphyseal screws and, therefore, potentially decreases rates of implant failure.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00068-022-01963-6.

Cement-augmented dynamic hip screw (DHS) to manage intertrochanteric fractures (ITFs) in the elderly: a prospective case series

Background:

The purpose of this study was to report early results in managing intertrochanteric fractures (ITF) in an elderly patient cohort using a cement augmented dynamic hip screw (DHS) by a relatively easy technique with cheap instruments available in any operative room.

Methods:

In this prospective study, 25 patients aged 70 yr or more who were diagnosed with ITF were included. Conventional DHS instruments were used for fixation. An endotracheal tube, and a disposable 50-cc plastic syringe with a nozzle were used to inject low viscosity polymethylmethacrylate (PMMA) bone cement inside the lag screw tract to obtain cement augmentation.

Results:

After an average follow-up of 8.3±2.1 mo, 20 patients (11 women and nine men) with a mean age of 76.9±5.8 yr were available for assessment. Sixteen patients were classified as AO/Orthopaedic Trauma Association (AO/OTA) type 31-A2, and four were classified as AO/OTA 31-A1. The average operative time was 70.3±9.5 min. All patients achieved radiographic fracture union by the last follow-up with an average tip apex distance of 21.8±1.9 mm. the average functional outcome according to the Salvati and Wilson scoring system was 27.4±5.9; 80% of the patients scored excellent and good. No complications were reported to the cement augmentation technique particularly lag screw cut out, implant failure, and femoral head avascular necrosis.

Conclusions:

Managing ITFs in elderly patients using a cement-augmented DHS revealed an acceptable functional and radiographic outcome with the use of a relatively easy, inexpensive, and safe technique.

Level of Evidence:

Level IV.

Cement augmentation for trochanteric fracture in elderly: A systematic review

BACKGROUND

Cement augmentation of internal fixation of hip fracture has reported to improve fracture stability in osteoporotic hip fractures, reducing the risk of cut-out of the sliding screw through the femoral head. The purpose of present study was to perform a systematic literature review on the effects of augmentation technique in patients with osteoporotic hip fractures.

MATERIAL AND METHODS

A comprehensive literature search was systematically performed to evaluate all papers published in English language included in the literature between January 2010 and July 2020, according to the PRISMA 2009 guidelines. In vivo and in vitro studies, case reports, review articles, cadaveric studies, biomechanical studies, histological studies, oncological studies, technical notes, studies dealing with radiological classifications and studies on revision surgery were excluded.

RESULTS

A total of 5 studies involving 301 patients were included. Patients had a mean age of 84.6 years and were followed up for a mean period of 11 months. The proximal femoral fractures were stabilized with implantation of the PFNA or Gamma nail and augmentation was performed with two different cements: polymethylmethacrylate (PMMA) in 4 studies and calcium phosphate (CP) in one study. Overall, 57.5% of patients reached the same or greater preoperative mobility, and postoperative Parker Mobility Score and Harris Hip Score were acceptable. No significantly complications were observed, and no additional surgery related to the implant was required.

CONCLUSION

The results of this systematic review show that cement augmentation is a safe and effectiveness method of fixation to treat trochanteric fractures.

Predicting Factors for Return to Prefracture Ambulatory Level in High Surgical Risk Elderly Patients Sustained Intertrochanteric Fracture and Treated With Proximal Femoral Nail Antirotation (PFNA) With and Without Cement Augmentation

Introduction:

Postoperative outcomes in the elderly patients with intertrochanteric fracture were generally poor with a low rate of return to prefracture ambulatory level (RPAL). Recent studies showed that proximal femoral nail antirotation (PFNA) with cement augmentation might be useful for postoperative functional recovery. This study aimed to compare the outcomes in elderly patients with high surgical risk, American Society of Anesthesiologist (ASA) grade 3 or 4, who sustained intertrochanteric fractures and were treated with PFNA with and without cement augmentation, and to correlate perioperative surgical factors with the RPAL.

Methods:

A retrospective consecutive series was conducted based on 135 patients with prefracture ambulation classified as independent in community with or without a single cane (68 in augmented group and 67 in control group). Perioperative data and data on the complications within 1-year postsurgery were collected and compared. Predictive factors for RPAL were analyzed via logistic regression analysis.

Results:

The overall 1-year postoperative mortality rate was 10% (n = 14) with no significant difference between groups (P = .273). The proportion of elderly patients with RPAL in the augmented group was significantly higher than for those in the control group (48% vs 29%, P = .043). Via univariate analysis, ASA grade 4 (P = .077), history of stroke (P = .035), and use of cement augmentation (P = .041) were correlated with RPAL. However, multivariate regression analysis showed that ASA grade 4 (odds ratio [OR] = 0.40, 95% confidence interval [CI]: 0.18-0.90, P = .026) and use of cement augmentation (OR = 2.72, 95% CI: 1.22-6.05, P = .014) were the significant predictors for RPAL.

Discussion and Conclusions:

The results of the present study showed that PFNA with cement augmentation is safe and effectiveness in the intertrochanteric fracture treatment of elderly. Postoperative functional recovery, like RPAL, in elderly patients who sustained intertrochanteric fractures is relatively low, especially in those with ASA grade 4. However, cement augmentation with PFNA might be helpful for increasing the RPAL in high-surgical-risk geriatric patients.

Design of Improved Intertrochanteric Fracture Treatment (DRIFT) Study: Protocol for Biomechanical Testing and Finite Element Analysis of Stable and Unstable Intertrochanteric Fractures Treated With Intramedullary Nailing or Dynamic Compression Screw

Background

Intertrochanteric hip fractures rank in the top 10 of all impairments worldwide in terms of loss in disability-adjusted years for people aged older than 60 years. The type of surgery is usually carried out with dynamic hip screw (DHS) devices or cephalomedullary nails (CMN). Cut-out of the hip screw is considered the most frequent mechanical failure for all implants with an estimated incidence ranging from 2% to 16.5%; this entails both enhancing our understanding of the prognostic factors of cut-out and improving all aspects of intertrochanteric fracture treatment.

Objective

The Design of Improved Intertrochanteric Fracture Treatment (DRIFT) study’s main objective is to provide intertrochanteric fracture treatment expertise, requirements and specifications, clinical relevance, and validation to improve treatment outcomes by developing a universal algorithm for designing patient- and fracture-oriented treatment. The hypothesis to be tested is that a more valgus reduction angle and implants of higher angles will lead to a more favorable biomechanical environment for fracture healing—that is, higher compressive loads at the fracture site with lower shear loads at the hip screw femoral head interface. A new implant with enhanced biomechanical and technical characteristics will be designed and fabricated; in addition, an integrated design and optimization platform based on computer-aided design tools and topology optimization modules will be developed.

Methods

To test this hypothesis, a biomechanical study comprising experimental loading of synthetic femora (Sawbones Inc) and finite element analysis (FEA) will be conducted. Detailed FEA of existing implants (DHS and CMN) implemented in different clinical cases under walking conditions will be performed to derive the stress and strain fields developed at the implant-bone system and identify critical scenarios that could lead to failure of therapy. These models would be validated against instrumented mechanical tests using strain gages and a digital image correlation process.

Results

After testing, geometric drawbacks of existing implants will be fully recognized, and geometric characteristics will be correlated with critical failure scenarios. The last step would be the numeric design, computer-aided design (using FEA codes and design packages), and optimization of the new proposed implant with regard to improved biomechanical surgical technique and enhanced mechanical performance that will reduce the possibility for critical failure scenarios.

Conclusions

The optimization of the biomechanical behavior of the fracture-osteosynthesis model by the application of the ideal reduction angle and implant is expected to have a positive effect to the rate of mechanical failure and, subsequently, the healing rates, morbidity, and mortality in this fragile patient group.

International Registered Report Identifier (IRRID)

DERR1-10.2196/12845

Cement augmentation of the Proximal Femoral Nail Antirotation (PFNA) - A multicentre randomized controlled trial

INTRODUCTION

New implant designs like the Proximal Femoral Nail Antirotation (PFNA) were developed to reduce failure rates in unstable pertrochanteric fractures in the elderly. Standardized implant augmentation with up to 6 mL of polymethylmethacrylate (PMMA) cement has been introduced to enhance implant anchorage by increasing the implant-bone interface in osteoporotic bone conditions. Biomechanically, loads to failure were significantly higher with augmentation. The primary objective of this study was to compare the mobility of patients with closed unstable trochanteric fractures treated by PFNA either with or without cement augmentation.

PATIENTS AND METHODS

A prospective multicentre, randomized, patient-blinded trial was conducted with ambulatory patients aged 75 or older who sustained a closed, unstable trochanteric fracture. Surgical fixation had to be performed within 72 h after admission. Outcomes were evaluated at baseline, during surgery, 3 to 14 days after surgery, 3 months, 6 months, and 12 months after surgery. To evaluate the primary objective, patients' walking speed was assessed by the Timed Up and Go (TUG) test. Secondary objectives included the analysis of implant migration assessed on radiographs, quality of life measured by the Barthel Index, mobility measured by the Parker Mobility Score, and complications.

RESULTS

Of 253 randomized patients, 223 patients were eligible: 105 patients were allocated to the PFNA Augmentation group and 118 to PFNA group. At 3 to 14 days after surgery, there was no statistical significant difference in mean walking speed between the treatment groups. For the secondary objectives, also no statistical significant differences were found. However, no patient in the PFNA Augmentation group had a reoperation due to mechanical failure or symptomatic implant migration compared to 6 patients in the PFNA group.

CONCLUSIONS

Augmentation of the PFNA blade did not improve patients' walking ability compared to the use of a non-augmented PFNA but might have the potential to prevent reoperations by strengthening the osteosynthesis construct.

Digital Assessment of the Implantation Angle of Proximal Femoral Nail Antirotation Helical Blade Using CT Three-dimensional Reconstruction

OBJECTIVES

To facilitate simple and safe manipulation during proximal femoral nail antirotation (PFNA) operation, we studied the range of safe implantation angle of the helical blade of the PFNA system by using a digital-based three-dimensional reconstruction model of CT images.

METHODS

Thirty-five healthy volunteers were recruited. Original multilayer helical CT scan data of the left femur were collected and imported into Mimics software. Anatomic features of the femur, including the safe implantation angle, anterior and posterior angle, were measured. Differences in each angle between male and female subjects were compared using Student's t test, and the determinants of each angle were analyzed by linear regression.

RESULTS

The mean safe implantation angle was 30.09° ± 4.73°, the mean anterior angle was 15.82° ± 2.07°, and the mean posterior angle was 14.27° ± 3.19°. All the three angles were greater in males than females (P < 0.05). Neck shaft angle and the diameter of the femoral neck and head were linearly correlated with the safe implantation angle, the anterior and posterior angle, respectively. Femoral neck diameter was a significant determinant of the safe implantation angle and posterior angle, respectively. Moreover, femoral neck diameter and femoral head diameter were significant determinants of the anterior angle.

CONCLUSIONS

The study has introduced and delineated a novel parameter, the safe implantation angle, for FPNA surgery, which may help orthopedic surgeons in deciding a safe range of PFNA operation and improve the accuracy of PFNA helical blade implantation.