Trochanteric fractures of the femur pose a significant health concern for the elderly; hip fractures impact 1.5 million people worldwide each year¹⁾. The number is rising steadily with continued aging of the global population.

Osteosynthesis using trochanteric femoral nail antirotation, proximal femoral nail antirotation, or Gamma3 nail intramedullary nailing devices is the preferred method of treatment for fractures of the trochanteric femur^2,3). Despite continual improvements and advancements to osteosynthetic devices, the rate of mechanical complication remains 20% or higher⁴⁾. Failure typically occurs as a result of varus collapse and implant cut-out, which may be preceded by migration, shortening of the femoral neck, and rotating head moments^5-7).

Cement augmentation has gained interest as a potential solution to address this issue, particularly in osteoporotic bone. Biomechanical studies have demonstrated that cement augmentation can be helpful in the effort to mitigate the previously mentioned challenges, particularly in cases involving unusual placement of an implant or poor bone density. It can enhance the resistance of the osteosynthesis device to shear stress resulting from the load^8,9). Clinical studies have reported promising results in terms of implant stability with use of cement-augmented nails^10-21). However, the available literature on the clinical benefit and safety of this augmentation technique in management of intertrochanteric and pertrochanteric fractures of the hip is limited. Therefore, the primary objective of this systematic review and meta-analysis is to examine the current literature on the safety of this construct, with a focus on perioperative complications and postoperative mortality.

1. Search Strategy

The comparison between cement augmentation and non-augmentation of cephalomedullary femoral nails in the management of pertrochanteric and intertrochanteric fractures adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) standards. A comprehensive search of PubMed, Cochrane, and Google Scholar (pages 1-20) was conducted, with a review of the literature up to 20 January 2024, for identification of relevant articles meeting the inclusion criteria. Using Boolean Operators, a combination of the keywords (([Cement*] AND ([Trochanteric] OR [Intertrochanteric] OR [Pertrochanteric])) was used for the search of PubMed and Cochrane, and “augmented nails in hip fracture” for Google Scholar. Reference lists from the included studies were also used in identification of literature. Screening of abstracts was performed by two authors and no conflicts arose during the selection process. Full-text screening was performed in the same manner. Extraction of data was performed by one researcher, and the selection of articles was verified by a different researcher. A summary of the process for selection of articles is shown in the PRISMA flowchart (Fig. 1).

Figure 1. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) diagram.

Inclusion criteria were (1) comparative studies including patients treated for inter or pertrochanteric fractures using cemented cephalomedullary nailing to non-cemented cephalomedullary nailing. Studies having the following characteristics were excluded: non-comparative studies, studies that reported irrelevant outcomes, or studies with missing data (such as standard deviation).

2. Data Extraction

The eligibility of the studies was determined by two reviewers in an independent manner. Extracted data included both perioperative complications and postoperative mortality.

3. Risk of Bias Assessment

Evaluation of risk of bias was performed independently by two authors. The Cochrane risk-of-bias tool for randomized studies was used with consideration for the randomization, concealing allocations, whether or not personnel and participants were blinded to the study protocol, whether or not assessment of the outcomes was performed in a blind manner, data from the completeness outcome, and whether or not there was any selective reporting (Fig. 2A). Trials that showed a high risk of bias in more than one section were classified as a high risk of bias. However, trials that showed a low risk of bias in every section were classified as a low risk of bias. Otherwise, trials were defined as having an unclear risk of bias. The ROBINS-I tool for assessing the risk of bias was used for non-randomized studies²²⁾, and studies that showed a critical risk of bias were excluded.

Figure 2. (A) Risk of bias in each included study. (B) Risk of bias as % in the included studies.

4. Statistical Analysis

Statistical analyses were performed using Review Manager 5.4 (The Cochrane Collaboration, 2020). Standardized mean differences and 95% confidence intervals (CI) were used for continuous data and a odds ratio with a 95% CI was used for dichotomous data. Q tests and I² statistics were used for analysis of heterogeneity. Random-effects was used for a P≤0.10 or I²>50% indicating considerable heterogeneity, and the fixed-effect model was used otherwise. Statistical significance was determined by a P-value of 0.05.

1. Characteristics of the Included Studies

A total of 779 articles were first identified. After removal of duplicates, 691 articles remained for screening abstracts. Only 20 articles were selected for full text screening. Seven studies^23-29) met the inclusion criteria. Four studies were retrospective, two were randomized trials, and one was a non-randomized prospective study (Table 1). The studies included 848 patients with 461 in the cemented group and 387 in the non-cemented group. A summary of the results of bias assessment for randomized trials is shown in Fig. 2B and for non-randomized studies are shown in Table 2. Assessment for publication bias was performed using a funnel plot (Supplementary Fig. 1, 2).

Table 1 . Main Characteristics of the Included Studies.

Study	Methods	Participants			Mean age (yr)			Participants		Follow-up time
		Cemented	Non-cemented		Cemented	Non-cemented		Cemented	Non-cemented
Dall’Oca et al.23) (2010)	Randomized controlled trial	35	36		85.3	82.3		1 cement leakage	0	12 months
Kammerlander et al.24) (2018)	Randomized controlled trial	87	135		86.1	85.6		1 cement leakage 1 avascular necrosis 1 hematoma requiring revision 1 gastrointestinal/cerebral bleeding 2 renal insufficiency 2 malunion 2 strokes 2 pneumonia 2 delirium 3 superficial wound infection 3 refracture 4 thromboembolic complication 5 myocardial infraction/arrythmia 30 others	1 hypersensitivity 1 poor reduction 1 blade loosening 1 malunion 1 superficial wound infection 1 dys-paraesthesia 1 gastrointestinal/cerebral bleeding 1 sepsis 1 thromboembolic complication 2 renal insufficiency 3 iliotibialis irritation 3 peri-implant fracture 3 hematoma requiring revision 4 refracture 5 myocardial infraction/arrythmia 6 strokes 6 delirium 8 pneumonia 47 others	12 months
Kim et al.26) (2018)	Retrospective	40	42		81.6	82.3		2 superficial wound infections	1 deep wound infection 1 reduction loss 1 excessive screw sliding 2 superficial wound infections 4 malunions	14 months
Kulachote et al.25) (2020)	Retrospective	68	67		85	83		11 urinary tract infection 5 cardiac complications 5 gastrointestinal bleeding 4 pneumonia 4 pressure ulcers 3 delirium 2 venous thromboembolism 1 acute renal failure 1 stroke	12 delirium 9 urinary tract infection 5 cardiac complications 5 gastrointestinal bleeding 5 acute renal failure 4 strokes 3 pressure ulcers 3 pneumonia 1 surgical site infection	12 months
Mochizuki et al.27) (2022)	Prospective non-randomized	32	31		87	87		19 non-specified	23 non-specified	1 week
Schuetze et al.28) (2021)	Retrospective	152	47		NA	NA		22 cardiac events	17 cardiac events	12 months
Yee et al.29) (2020)	Retrospective	47	29		85.1	86.1		5 not specified	4 not-specified	3 months

NA: not available..

Table 2 . Bias Assessment of the Included Non-randomized Studies.

Study	Confounding bias	Selection bias	Classification bias	Bias due to deviation from interventions	Bias due to missing data	Bias in measurement of outcomes	Bias in selection of reported results	Results
Kim et al.26) (2018)	Low risk	Low risk	Low risk	Low risk	Low risk	Moderate risk	Low risk	Moderate risk
Kulachote et al.25) (2020)	Low risk	Low risk	Low risk	Low risk	Low risk	Moderate risk	Low risk	Moderate risk
Mochizuki et al.27) (2022)	Low risk	Low risk	Low risk	Low risk	Low risk	Moderate risk	Low risk	Moderate risk
Schuetze et al.28) (2021)	Low risk	Low risk	Low risk	Low risk	Low risk	Moderate risk	Low risk	Moderate risk
Yee et al.29) (2020)	Low risk	Low risk	Low risk	Low risk	Low risk	Moderate risk	Low risk	Moderate risk

2. Perioperative Complications

Seven articles included data on perioperative complications in 848 patients (461 in the cemented group vs. 387 in the non-cemented group). A lower rate of perioperative complications was observed in the cemented group (P=0.002, odds ratio [OR] 0.60, 95% CI 0.44-0.84; Fig. 3).

Figure 3. Forest plot showing the lower rate of perioperative complications in cemented compared to non-cemented cephalomedullary nailing.

3. Postoperative Mortality

Five articles included data on postoperative mortality in 595 patients (282 in the cemented group vs. 313 in the non-cemented group). No difference in mortality was observed between the two groups (P=0.30, OR 0.74, 95% CI 0.42-1.30; Fig. 4).

Figure 4. Forest plot showing a similar rate of postoperative mortality in cemented and non-cemented cephalomedullary nailing.

Trochanteric fractures of the femur pose a serious health concern for the elderly, and the incidence is increasing with aging of the population¹⁾. The standard treatment includes the use of cephalomedullary nailing^2,3). However, this approach to management has been associated with mechanical complications that can potentially be mitigated with use of cement augmentation. Our meta-analysis is the first to compare the safety of cementing cephalomedullary nails in management of intertrochanteric and pertrochanteric fractures. Our findings showed a lower rate of perioperative complications and no significant difference in postoperative mortality. Of particular interest, our analysis, which differs from a previous meta-analysis conducted in 2021, includes a wider range of studies while excluding data related to dynamic hip screws, which were not part of our research focus³⁰⁾.

Based on the current literature cement-augmented nails can provide exceptional implant stability^10-21). In fact, this enhanced stability can potentially contribute to a reduction in the rate of perioperative complications, particularly cardiopulmonary complications. One possible explanation is that the improved stability of the construct can enable a more rapid return to daily activities, consequently reducing the postoperative duration of immobilization^{17,23-27,31,32)}. In addition, numerous studies have also reported a higher rate of return to pre-ambulatory levels of activity with use of cement-augmented cephalomedullary nails, further supporting this assertion^25,33-35). Regarding local mechanical complications, the superior stability and the lack of impact on the elasticity of the implant can contribute to reduced femoral shortening, varus collapse, non-union, and improving postoperative radiographic outcomes^23,24,26). In addition, the cost-effectiveness of cement augmentation has been demonstrated, resulting in a cost saving of 50.3€/patient compared to non-augmented nails. It can also increase the quality-adjusted-life-years by 0.01 per patient, primarily due to a reduction in the rates of revision surgery associated with mechanical failure³⁶⁾.

Despite the introduction of foreign material, due to the closed system and absence of contact with air during the processes of cement preparation and injection, concerns regarding an increased risk of superficial and deep infections can be mitigated in cement augmentation²³⁾. Cement related complications are rare^24,25,37,38). Even though the risk of osteonecrosis of the femoral head is negligible despite the fact that the exothermic reaction generated in-situ by the injected cement could potentially be a cause of thermal necrosis in certain areas of the bone¹⁶⁾, the minimal amount of cement injected (3 mL) can explain why this complication was not observed³⁹⁾. None of the included studies reported hypersensitivity or local soft tissue reactions associated with application of cement. The small amount of cement extravasation into the hip joint resulting from entry of the guide wire into the femoral head is another augmentation-specific complication. In fact, Kammerlander et al.²⁴⁾ reported on a similar case; however, no harm to the hip joint was observed. This issue can be prevented with routine fluoroscopic evaluation of the location of the guide wire and performance of a contrast dye test prior to application of cement and connections to the hip joint can be ruled out³⁸⁾. In addition, Schuetze et al.²⁸⁾ who reported that there were no significant intraoperative changes in heart rate or oxygenation following injection of cement observed low grades of bone cement implantation syndrome (based on the classification by Donaldson). The low pressure and volume of the injected cement might explain the latter²⁸⁾. Nonetheless, it the surgeon should inform the anesthetist prior to injection of cement, allowing ample time to prepare for potential complications, no matter how small the risk may be²⁸⁾. Therefore, when executed properly, a virtually non-existent risk of augmentation-specific complications is possible.

This study has several limitations that should be acknowledged. First, the data used for analysis were pooled, and individual patient data were unavailable, which restricted the performance of more comprehensive analyses. In addition, some variability may have been introduced due to the inclusion of both retrospective and prospective randomized and non-randomized trials. In addition, detailed information regarding the types of complications was not included in all studies, which precluded performing a sub-analysis based on the specific types of complication. In addition, the risk of bias in outcome assessment was high due to the absence of blinding. However, it is worth noting that only comparative studies were included, thereby minimizing the risk of matching bias. In addition, a meticulous and discerning selection process was used in this study, resulting in a less heterogenous study population and reducing the risk of bias. Nevertheless, the high selection bias that might result from use of this method should be noted. This study is the first meta-analysis to compare cement augmentation to non-augmentation of cephalomedullary nails in management of pertrochanteric and intertrochanteric fractures, and the fact that seven studies were included in this meta-analysis, which provides a sufficient sample size for obtaining reliable results, should be emphasized.

This study is the first meta-analysis to examine the safety of cement-augmented cephalomedullary nails in management of intertrochanteric and pertrochanteric fractures. According to the findings, cement augmentation can effectively reduce perioperative complications, while no significant difference in postoperative mortality rates was observed. The favorable outcomes can be attributed to the improved stability provided by cement augmentation, which can reduce the likelihood of mechanical failure and facilitate an earlier return to daily activities, thereby minimizing cardiopulmonary complications. In addition, the use of a closed system during cement augmentation can eliminate the additional risk of deep or superficial infection. The importance of using the appropriate technique for cement augmentation cannot be overstated, as it can ensure that the risk of cement-associated complications remains negligible. Consequently, use of standardized techniques for implant augmentation can potentially improve patient outcomes while also reducing costs.

No funding to declare.

No potential conflict of interest relevant to this article was reported.

Supplementary data is available at https://hipandpelvis.or.kr/.