Peri-implant femoral fractures around intramedullary nails: current management strategies and outcomes—a narrative review

Abstract

Background

Peri-implant femoral fractures occurring around an intramedullary nail (“around the nail” fractures) represent a complex challenge in orthopedic trauma. These fractures have been increasingly reported over the last two decades, and studies from 2001 to 2025 were selected to capture contemporary surgical techniques and implant designs. Management remains controversial due to both mechanical issues (implant loosening, malposition, nail breakage, and fracture at stress risers) and systemic complications (infections, thromboembolic events, and medical comorbidities).

Materials and methods

A systematic review was conducted following PRISMA guidelines. PubMed, Scopus, and Google Scholar were searched for studies published between 2001 and 2025. Inclusion criteria comprised studies on adult patients undergoing surgical treatment for peri-implant femoral fractures after anterograde nailing. Data on demographics, fracture patterns, implant characteristics, surgical strategies, and outcomes were extracted. Methodological quality was assessed using the MINORS score.

Results

The study included 315 patients with a mean age of 82.3 years, predominantly female (2:1 ratio). Most fractures were treated with anterograde intramedullary nails, mainly short nails. A total of 211 peri-implant fractures were analyzed, with the majority occurring around the nail (58.8%). Fractures were more common within 12 months post-surgery. Surgical treatment involved reinforcement with long nails or lateral plating. The union rate was 93.7%, with a mean healing time of 23.96 weeks. Complications included infections (19 cases), systemic issues, and mechanical problems (implant loosening, breakage, or malposition), leading to additional surgeries in some cases. Infection was linked to higher mortality rates (44.4% vs. 11.8%).

Conclusion

There is no definitive consensus on the optimal surgical treatment of “around the nail” femoral fractures. Treatment choice is influenced by fracture location, implant stability, and patient comorbidities. Plating, nail revision, and prosthetic replacement each carry specific risks and benefits. The high complication and mortality rates, along with variability in outcomes, highlight the need for standardized classification systems and high-quality comparative studies to guide treatment in this challenging clinical scenario.

Introduction

Proximal femur fractures (PFFs) are among the most prevalent and debilitating injuries observed in the elderly population, affecting approximately 18% of women and 6% of men worldwide. These fractures primarily occur as a result of low-energy falls, frequently in the context of osteoporosis, and are associated with considerable morbidity, functional deterioration, and elevated mortality rates, particularly within the first year following injury [22]. As life expectancy continues to improve, the incidence of PFFs is projected to rise, thereby increasing the burden on healthcare and social care systems [14]. The economic repercussions of these injuries are substantial, encompassing prolonged hospitalization, rehabilitation, and the necessity for long-term assistance, all of which contribute to escalating costs [4].

Among PFFs, femoral neck fractures (FNF) and pertrochanteric fractures (PF) collectively constitute over 90% of the cases, occurring at approximately equivalent frequencies. These injuries are predominantly managed through surgical intervention to restore anatomical alignment, enable early mobilization, and mitigate complications associated with extended immobilization, such as deep vein thrombosis, pneumonia, urinary tract infections, and pressure ulcers [3]. Delayed or conservative management has been associated with less favorable functional outcomes and increased mortality rates [5].

Intramedullary nailing (IMN) has emerged as the gold standard for the treatment of diaphyseal and certain proximal femur fractures due to its biomechanical benefits. IMN offers superior load-sharing capabilities, enhances axial and rotational stability, and permits earlier weight-bearing compared to extramedullary fixation methods, such as dynamic hip screws (DHS). These advantages contribute to improved functional recovery and reduced rates of implant failure [40]. However, complications including delayed union, nonunion, malalignment, and hardware failure may arise, thereby requiring revision surgery. Additionally, risk factors such as poor bone quality, suboptimal reduction, and excessive varus positioning of the implant have been linked to an increased risk of mechanical complications [21, 32].

A particularly challenging clinical scenario manifests when patients with a previously implanted intramedullary nail sustain a new femoral fracture. These so-called "around the nail" fractures present unique challenges concerning both diagnosis and surgical management. The pre-existing implant modifies the biomechanical properties of the femur, potentially influencing load distribution and fracture healing [12]. Additionally, the presence of the nail may hinder standard fixation techniques, thereby constraining the options available to the surgeon. Several critical factors must be considered, including implant stability, fracture morphology, bone stock, and the patient's overall health status [23].

The fracture pattern plays a crucial role in both diagnosis and management. These injuries can present with a wide spectrum of morphologies—from peri-implant fractures adjacent to the distal tip of the nail to complex comminuted diaphyseal injuries. Some patterns, particularly those with minimal displacement or stable configurations, may be amenable to conservative treatment under close monitoring. Others necessitate timely surgical intervention to avoid complications and optimize functional recovery [12]. Early versus delayed treatment remains a subject of debate, although emerging data suggest that early stabilization, where feasible, is associated with better outcomes [24].

Current treatment strategies for "around the nail" fractures include implant retention with supplementary fixation (e.g., lateral locked plating), nail exchange, or conversion to arthroplasty in cases of poor bone stock or complex fracture patterns. Each approach has specific indications, benefits, and limitations, and treatment is often tailored to the individual patient. However, there is no universally accepted gold standard for managing these fractures. Decisions are frequently guided more by surgeon experience and institutional protocols than by rigorous, evidence-based guidelines. Furthermore, there is a lack of dedicated classification systems for these injuries, which complicates both clinical decision-making and the interpretation of outcomes across studies [34].

This study aims to analyze the current evidence surrounding "around the nail" fractures, evaluating outcomes associated with different surgical strategies. By synthesizing available data, we seek to clarify best practices, optimize treatment algorithms and contribute to the ongoing advancement of orthopedic trauma care.

Materials and methods

The review followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines [27], ensuring a thorough and systematic approach to data collection and analysis (Fig. 1). This systematic review has also been registered with the International Prospective Register of Systematic Reviews (PROSPERO), under registration number 1032847.

Fig. 1.

PRISMA flowchart

Search strategy

The search was performed across several online databases, including PubMed, Scopus, and Google Scholar. The search string used in PubMed was as follows: Femur Fracture AND ((around nail) OR (peri nail) OR (peri-nail) OR (peri-implant) OR (peri implant)).

We carefully examined the titles and abstracts of all retrieved articles to assess their eligibility for inclusion in the review. The criteria for inclusion were as follows: the studies must involve human adults and be published in English. We included randomized trials, uncontrolled comparative trials and case series.

When there was uncertainty, the full article was retrieved for further examination. The senior author and the content area experts then obtained the full text of all articles and reviewed them to minimize any bias that could arise from preconceived opinions about the studies and their findings. This process was further enhanced by following up on the reference lists of relevant studies to identify additional articles.

Two authors (A.E.M. and G.B.) independently reviewed the abstracts, obtaining the full texts for any abstracts that were inconclusive. Any differences between the reviewers were discussed, and if disagreements remained, the senior author (R.V. or G.M.) was consulted. The reference lists of the selected articles were manually checked to identify additional relevant studies. All selected studies were then analyzed retrospectively by three authors (D.M., G.B., and G.C.), who extracted and entered the data into an Excel worksheet. Finally, the data sheet was reviewed by four authors (R.V., E.D.G., A.E.M., G.C.), who reached an agreement on the extracted data. Additionally, three authors (E.D.G., G.M., and A.E.M.) independently evaluated the risk of bias using standardized criteria. The references of the identified papers were searched to find further relevant articles, and all journals were considered. Of the 41 studies excluded after full-text assessment, the reasons were as follows: 12 studies involved pediatric populations, 9 studies focused on oncological cases, 7 studies reported non-surgical treatment methods, 5 studies had follow-up shorter than six months, 4 studies presented duplicate data from previously published work, and 4 studies were not accessible through institutional or public databases (Fig. 1).

Inclusion and exclusion criteria

The eligibility criteria for our analysis were established to select studies that met high methodological and reporting standards. We included studies involving adult men and women aged 18 years or older who underwent surgical treatment for "around the nail" fractures. Acceptable study designs comprised retrospective and prospective case series, controlled clinical trials, and randomized controlled trials. Only studies published in English language that reported clinical, radiological or complication outcomes with a follow-up period of at least six months were considered and with a minimum sample size of ten patients per study. Exclusion of studies with fewer than ten patients was performed in order to ensure adequate statistical power and methodological rigour. Additionally, all articles had to be accessible through institutional or public journal databases.

To maintain the quality and relevance of our analysis, we excluded certain studies. This included research focused on pediatric populations (those younger than 18 years) and studies involving oncological patient groups. We also excluded non-surgical treatment methods such as cast immobilization, electromagnetic field therapy or ultrasound. Furthermore, articles that were not accessible through institutional resources or the British Library, studies with insufficient follow-up duration (less than six months), and those presenting duplicate data from previously published research were omitted. Lastly, studies that did not specify key outcomes, such as union incidence, were excluded as well (Table 1).

Table 1.

Inclusion and exclusion criteria

Study aspect	Inclusion criteria	Exclusion criteria
Types of studies	1. Retrospective and prospective case series 2. Controlled clinical trials 3. Randomized controlled trials 4. Non-blinded and blinded studies 5.English language	1. Studies reporting the outcomes of non- surgical methods (cast immobilization, electromagnetic field therapy, ultrasound) 2. Articles not available through the British Library or our institutions online journal access
Types of participants	1. Adult men and women (age greater or equal to 18 years) who underwent a surgical procedure to achieve anatomical reduction	1. Pediatric cases (age less than 18 years) 2. Patients with non-operative management or non-standard interventions
Types of interventions	1. Any surgical intervention for the treatment of “around the nail” fractures	1. Experimental or less common treatment modalities not supported by sufficient data (< 10 patients), to ensure meaningful comparison and minimize bias from anecdotal reports

Data extraction and analysis

The methodological rigor of each study was evaluated utilizing the Methodological Index for Non-Randomized Studies (MINORS) score, which permits a maximum of 24 points for comparative analyses and 16 points for non-comparative analyses [38]. Two researchers independently allocated MINORS scores and subsequently reached a consensus regarding the final score.

Statistical significance was determined at a threshold of p < 0.05. The gathered data were analyzed and organized using SPSS software (SPSS, Inc., Chicago, IL, USA). Categorical variables are displayed as frequencies and percentages, while continuous variables are presented as means with their standard deviations. All numerical data have been rounded to one decimal place for enhanced precision.

Results

Patient demographics

A total of 315 patients were included across the selected studies contributing to the updated dataset. The mean age of the population was 82.3 ± 4.5 years, with values ranging from 73.0 to 87.6 years, confirming a clear predominance of elderly individuals. Most patients were over the age of 70. One study did not report age data, slightly limiting the completeness of the age analysis.

Sex distribution was incompletely reported, with four studies not specifying the sex of the participants. However, among the remaining data, there were 31 male and 173 female patients, indicating a marked female predominance, approximately in a 2:1 ratio. Body mass index (BMI) was reported in 7 studies, with values ranging from 19.6 to 27.0 kg/m².

The general health status of patients was assessed using the American Society of Anesthesiologists (ASA) classification in a limited number of studies. Among those reporting, most patients were classified as ASA II or ASA III, while a smaller proportion fell into ASA IV, reflecting a population with significant but manageable systemic disease. It is important to note that ASA classification was not reported in six studies, which limits the generalizability of these findings.

Similarly, the Charlson Comorbidity Index (CCI) was inconsistently reported. While one study indicated that 70.3% of patients were classified as CCI category III, eight studies did not include any information on comorbidity scoring. This inconsistency makes it difficult to accurately quantify the burden of chronic disease across the entire cohort.

Anticoagulant therapy was reported in 9 studies. Among those, 14.1% of patients received direct oral anticoagulants (DOACs), 7.8% warfarin, 1.6% heparin, and 76% were not on anticoagulation.Smoking status was inconsistently reported. The absence of comprehensive data from the other studies limits the possibility of drawing robust conclusions about the influence of anticoagulants on surgical outcomes or complication rates (Table 2).

Table 2.

Patient demographics

First author	No. patients	Age	range/ SD	Sex
				M	F
Aguado-Maestro et al. [1]	33	87.6	SD 6.2, 70–98	3	30
Luca Bianco Prevot et al. [31]	25	84.5	70–92	2	23
Wulbrand et al. [41]	41	81.6	± 11.8	N/A	N/A
Manuela Poroh et al. [30]	36	73	± 13.7	N/A	N/A
Fernando Bidolegui et al. [6]	16	80.9	72–92	3	13
Vilar-Sastre et al. [21]	43	87.3	N/A	5	38
Halonen et al. [22]	14	85.5	61–105	4	10
JiříSkála-Rosenbaum et al. [37]	17	77.1	N/A	5	12
Müller et al. [24]	23	84.7		3	20
Henry Goodnough et al. [15]	33	79.7		6	27
Bjørgul et al. [7]	17	N/A	N/A	N/A	N/A
Osnes et al. [27]	17	83	71–94	N/A	N/A

Implant characteristics

All patients included in the present analysis were treated for femoral fractures using anterograde intramedullary nailing, which was the exclusive surgical technique adopted across all studies.

The type of intramedullary nail was specified in a substantial proportion of patients.Gamma nails (Stryker, Kalamazoo, MI, USA) were used in 67 cases, representing 21.3% of patients with a known implant type. PFNA (Proximal Femoral Nail Antirotation, DePuySynthes, Johnson & Johnson, USA) systems were the most frequently used, accounting for 68 patients (21.6%), followed by TFNA (Trochanteric Fixation Nail Advanced, DePuySynthes, Johnson & Johnson, USA) in 9 patients (2.9%). Additionally, Affixus nails (Zimmer Natural Nail, Zimmer Biomet, USA) and ZNN (Zimmer Natural Nail, Zimmer Biomet, USA) implants were each used in 1 patient (0.3%).In contrast, 169 patients (53.7%) were simply reported as having undergone "nailing" without further detail, highlighting a significant lack of standardization in implant documentation across the included studies.

Regarding nail dimensions, we classified implants as short when their length was ≤ 200 mm, and long when greater than 200 mm.Diameters ranged from 10 to 13 mm, and the nail angles varied between 125° and 135° where reported.

Among the studies that provided specific data, 85 patients (64.4%) were treated with short nails, and 47 patients (35.6%) with long nails, for a total of 132 cases with quantifiable data. However, in three studies, both short and long nails were reportedly used, but without detailing the exact distribution between the two categories. Moreover, one study did not report nail dimensions at all, further limiting the granularity of this analysis.

The choice between short and long nails appeared to depend on several factors, including fracture morphology, bone quality, and the presence of previous implants. Short nails were generally preferred in more stable, proximal fracture patterns, while long nails were selected for more distal or unstable configurations requiring greater mechanical support.

Despite the variability in implant type and reporting, the overall bone union rate was high across the included studies, reinforcing the efficacy of anterograde intramedullary nailing in this clinical context. Nevertheless, the lack of standardized reporting on implant dimensions and models limits deeper comparative analysis (Table 3).

Table 3.

Implant characteristics

First author	Type of implant	Dimension of implant
Aguado-Maestro et al. [1]	9 TFNA, 8 Gamma, 14 PFNA, 1 AFFIXUS, 1 ZNN	L 17–24 cm, W 10–12 mm, A 130°(1 a 125°)
Luca Bianco Prevot et al. [31]	25 Gamma	L 180 mm; 270 mm, 340 mm
Wulbrand et al. [41]	41 Nailing	L 25 short; 6 long
Manuela Poroh et al. [30]	36 Nailing	N/A
Fernando Bidolegui et al. [6]	16 Nailing	L 10 short; 6 long
Vilar-Sastre et al. [21]	43 Nailing	L 30 short; 13 Long
Halonen et al. [22]	14 PFNA	L 2 short (200 mm),1 long, 11 intermediate(240 mm)
JiříSkála-Rosenbaum et al. [37]	17 PFNA	L 240 mm, W 11-13 mm, A 130–135°
Müller et al. [24]	23 PFNA	L 18 240 mm; 5 380–420 mm
Henry Goodnough et al. [15]	33 Nailing	L 19 short, 14 long
Bjørgul et al. [7]	17 Gamma	W 11mmm, A 135°
Osnes et al. [27]	17 Gamma	L 16 short, 1 long; W 11 mm

Fracture patterns

A total of 211 peri-implant fractures were analyzed across the included studies. The discrepancy between the 315 included patients and 211 peri-implant fractures reflects the fact that not all patients developed a fracture during follow-up, and some studies did not report complete fracture data.

Based on anatomical location and available data, peri-implant fractures were classified into three main patterns: Type A (tip of the nail), Type B (around the nail, midshaft), Type C (below the stem / distal). Specifically, among cases with precise localization, 97 fractures (46.0%) were located at the tip, 94 fractures (44.5%) below the stem, and 20 fractures (9.5%) were reported around the nail without further distinction between midshaft and distal.

It is important to note that three studies (Bianco, Bjorgul, and Osnes) reported fracture location only as "around the nail," without distinguishing between midshaft and distal. Therefore, some of these cases may overlap with Type A or Type C, implying that the true numbers of tip or distal fractures may be underestimated.

When reported, peri-implant fractures were frequently associated with low-energy trauma such as falls from standing height, accounting for approximately 72% of cases. In some studies, mechanical factors including stress risers at the tip of the nail (14%), inadequate initial fracture reduction (8%), or implant malposition (6%) were suggested as contributing factors. Many studies (50%) did not provide explicit information on the mechanism of fracture, highlighting a gap in the literature.

Implant mobilization was reported in 32 patients, indicating mechanical instability or early signs of construct failure. Yet, three studies (Bianco, Rosenbaum and Müller) did not report any data regarding implant mobilization, potentially leading to an underestimation of the true incidence.

Concerning the integrity of implants, three instances of implant breakage have been documented. Notably, all incidents occurred in patients who were treated with long intramedullary nails, thereby supporting the hypothesis that longer constructs may possess an increased susceptibility to fatigue and mechanical failure. Furthermore, a study conducted by Bianco et al. did not report any instances of implant breakage, which further constrains the comprehensiveness of the available data.

Taken together, these findings highlight the clinical importance of accurately reporting the anatomical distribution of peri-implant fractures and associated mechanical complications. Standardized documentation of fracture location, implant behavior, and failure modes is crucial to guide surgical decision-making and improve outcomes in this fragile patient population (Table 4).

Table 4.

Fracture patterns

First author	Implant and fracture
	Around the nail	At the tip	Below the nail	Loosening?	Implant breakage?
Aguado-Maestro et al. [1]	13	8	12	15	1
Luca Bianco Prevot et al. [31]	20	0	5	8	NA
Wulbrand et al. [41]	0	6	35	11	1
Manuela Poroh et al. [30]	13	23	0	6	0
Fernando Bidolegui et al. [6]	0	14	2	0	0
Vilar-Sastre et al. [21]	32	11	0	0	0
Halonen et al. [22]	2	10	2	0	3 (all long)
JiříSkála-Rosenbaum et al. [37]	10	7	0	NA	0
Müller et al. [24]	2	18	3	NA	0
Henry Goodnough et al. [15]	0	0	33	0	0
Bjørgul et al. [7]	17	0	0	0	1
Osnes et al. [27]	15	0	2	0	0

Time to fracture and treatment strategy

The time between primary surgery and the occurrence of a peri-implant fracture varied considerably across the included studies. Reported intervals ranged widely, with the overall range spanning from 2 to 47 months. The pooled mean time to fracture was 18.1 months, indicating that these complications tend to arise within the first two years following the index procedure. Several studies noted that approximately 25–26% of fractures occurred within the first 12 months, suggesting the contribution of early mechanical failure or biological factors such as delayed consolidation. In some cases, peri-implant fractures were observed in the presence of nonunion, reinforcing the hypothesis that insufficient primary healing predisposes patients to implant failure.

It should be noted that three studies did not report the time to fracture, which limits the completeness of the overall temporal analysis.

All patients across the reviewed studies underwent surgical treatment, with no cases managed conservatively, reflecting the high mechanical instability and clinical severity of these fractures.

Type A (tip fractures) often managed with exchange or longer nails to restore stability, Type B (around the nail) frequently required plating or nail revision, Type C (distal fractures below the stem): treated with distal femoral plates or long nails spanning the fracture. Across the cohort, 26 patients were treated with long intramedullary nails (including 8 cemented), and 7 underwent fixation with condylar plates. One patient was treated with a cemented endoprosthesis.

Plate fixation was widely represented: 21 patients received plates (unspecified), 17 lateral plates, 8 distal femoral plates, 17 LISS plates, and 1 DFN (Distal Femoral Nail). In addition, 10 patients underwent re-osteosynthesis with long nails, and 6 patients had distal locking of the nail. Exchange nailing was performed in 6 patients, while renailing procedures were documented in 20 patients. Other methods included 3 PFN long nails, 1 case with k-wires cerclage, 2 cases of longer nail combined with k-wires cerclage, and 1 case treated with a short Gamma nail and a retrograde nail for the long segment.

In one series, 12 patients underwent re-osteosynthesis with longer nails alone, and 10 patients were treated with plates following failure of short nails.

Finally, 7 short nail failures were managed with revision nailing. While 2 conservative cases were mentioned in one dataset, all patients in the final analysis were treated surgically.

Where surgical timing was reported, the mean time from diagnosis to intervention ranged between 2.14 days and 2.56 days, with a range from 0 to 7 days. In one cohort, 56.3% of patients were treated within the first 24 h, while 43.7% underwent surgery after that threshold. Several studies did not specify the exact surgical timing, limiting inter-study comparison (Table 5).

Table 5.

Time to fracture and treatment strategy

First author	Time to fracture (months)	Type of surgery	Time to surgery (days)
Aguado-Maestro et al. [1]	47.2 (0–194)	26 long nails (8 cemented), 7 condilar plate (1 non overlapping, refracture 2 m), 1 cemented endo	2.56 (0–7)
Luca Bianco Prevot et al. [31]	38.0 ± 57.1	21 plate, 4 nailing	N/A
Wulbrand et al. [41]	< 12: 25%	Lateral locking plates, cephalomedullary nails, arthroplasty	< 24 h: 56.3%, > 24 h: 43.7%
Manuela Poroh et al. [30]	16.5	17 plate e 20 re-nailing	N/A
Fernando Bidolegui et al. [6]	12.7475 (range 4–30)	8 distal femoral plate, 8 nails	N/A
Vilar-Sastre et al. [21]	Median 21.6	Plating or renailing, cable cerclage if needed	NA
Halonen et al. [22]	102 days	8 fixation with plate, 6 exchange nail	2.14 ± 0.77
JiříSkála-Rosenbaum et al. [37]	57 days	6 distal locking of the nail, 1 plate, 10 re-osteosynthesis with long nail	N/A
Müller et al. [24]	21.17	17 LISS, 1 DFN, 1 WIRES, 3 PFN long, 1 conservative	N/A
Henry Goodnough et al. [15]	N/A	long nail fractures all tretaed with plate, short nail fractures: 7 revision of nail, 2 conservative, 10 plate	N/A
Bjørgul et al. [7]	N/A	Reosteosynthesis	N/A
Osnes et al. [27]	2.5	12 longer nail, 2 longer nail + cerclage, 1 short gamma nail + retrograde nail for the long	N/A

Postoperative management and functional recovery

Postoperative management protocols, including weightbearing restrictions and rehabilitation strategies, varied across the included studies. In several cohorts, specific protocols were reported: progressive loading starting at 4 weeks with full weightbearing allowed at 6 weeks, and in another study, a restriction to at least 20 kg of weightbearing was imposed during the early postoperative period. In other series, weightbearing was permitted as tolerated, although detailed protocols were often not specified. One study provided comparative data showing a median restriction duration of 9.1 weeks, with patients treated with plates requiring significantly longer restriction (12.4 weeks) compared to those treated with nails (3.3 weeks, p < 0.01). Moreover, patients who developed local complications required a longer period of weightbearing limitation (13.2 weeks vs. 7.4 weeks in those without complications, p = 0.04).

The duration of follow-up was generally adequate, with most studies reporting a minimum of 12 months, and some extending beyond 24 months. Median or mean follow-up durations ranged from 12 to 40.3 months, though not all studies clearly stated whether the reported value was a minimum, mean, or median. One study explicitly reported a median follow-up of 22.4 months (IQR: 12.2–28.6).

Functional outcomes were variably reported. The Parker Mobility Score (PMS) was the most commonly used functional measure. Among the few studies providing detailed functional results, one reported a mean PMS loss of 4.16 points, reflecting a significant decline in ambulatory function post-fracture. Another study documented a postoperative PMS of 5.15 (range: 0–9), while a third reported a mean score of 5.2 at follow-up. Although these data are limited, they suggest that most patients experienced a moderate reduction in mobility, with scores remaining in the mid-to-lower range of the PMS scale (Table 6).

Table 6.

Postoperative management and functional recovery

First author	Weight bearing restrictions	Follow up (months)
Aguado-Maestro et al. [1]	N/A	> 12
Luca Bianco Prevot et al. [31]	Progressive loading at 4 weeks, full WB 6 weeks	≥ 12
Wulbrand et al. [41]	At least 20 kg WB allowed	12
Manuela Poroh et al. [30]	N/A	12
Fernando Bidolegui et al. [6]	N/A	21.51
Vilar-Sastre et al. [21]	Median 9.1w (12.4 plating vs. 3.3 nailing)	22.4
Halonen et al. [22]	N/A	≥ 24
JiříSkála-Rosenbaum et al. [37]	Astolerated	N/A
Müller et al. [24]	N/A	40.3
Henry Goodnough et al. [15]	N/A	12
Bjørgul et al. [7]	N/A	12
Osnes et al. [27]	N/A	26.25

Bone healing and union rate

Bone healing outcomes were reported in the majority of included studies, although the level of detail and consistency varied. The overall weighted union rate across the studies was 93.7%, indicating a generally high success rate of fracture consolidation following surgical treatment of peri-implant femoral fractures. Most individual studies reported union rates of 90% or higher, with seven studies documenting a 100% union rate. One study reported a union rate of 94.6%, while another indicated a notably lower value of 72%, which may reflect differences in patient selection, implant choice, or surgical technique.

The time to union was reported less consistently. The weighted mean time to union was 23.96 weeks, based on the studies that provided usable data. Individual results ranged broadly. One study reported a mean time to union of 6.04 months (range: 1–36 months), while another described a mean time of 11.48 ± 1.67 weeks (range: 8–16 weeks), and a further study documented a median of 7.7 months (IQR: 3.9–11.1). Notably, in patients who developed local complications, the time to union was significantly prolonged, reaching up to 13.2 months (p = 0.04). Another report cited a healing time of 18 weeks, although without stratified analysis.

Despite some heterogeneity in reporting methods, the data confirm that bone healing is generally successful in this population, though delayed union may occur, particularly in the presence of postoperative complications. The wide variability in time to union emphasizes the influence of both patient-related factors (e.g., bone quality, comorbidities) and treatment-specific variables (e.g., implant type, surgical timing, fixation technique) (Table 7).

Table 7.

Bone healing and union rate

First author	Bone union rate	Mean time to bone union (weeks)
Aguado-Maestro et al. [1]	72%	6.04 (1–36)
Luca Bianco Prevot et al. [31]	NA	N/A
Wulbrand et al. [41]	NA	N/A
Manuela Poroh et al. [30]	94.6%	N/A
Fernando Bidolegui et al. [6]	100% union rate	11.48 ± 1.67 (8 – 16)
Vilar-Sastre et al. [21]	90%	7.7
Halonen et al. [22]	100%	N/A
JiříSkála-Rosenbaum et al. [37]	100%	18
F Müller et al. [24]	100%	N/A
Henry Goodnough et al. [15]	100%	N/A
Bjørgul et al. [7]	100%	N/A
Osnes et al. [27]	100%	N/A

Complications

Postoperative complications were frequently reported across the included studies and involved both surgical and medical adverse events. The most commonly documented complication was surgical site infection (SSI), with a total of 19 confirmed cases across the dataset. Additionally, 2 patients developed COVID-19 during the perioperative course. Infections were often associated with a worse prognosis, and in one study, a statistically significant increase in mortality was observed among infected patients, with a 44.4% mortality rate in patients with infection versus 11.8% in those without (p = 0.03).

Beyond infections, a wide range of systemic complications was described. These included acute renal failure, popliteal thrombosis, pulmonary embolism (PE), lower respiratory tract infections, pneumonia, delirium, myocardial infarction, atrial fibrillation, hemorrhagic cholecystitis, gastrointestinal bleeding, somnolence, and respiratory failure. These complications often led to extended hospital stays and, in some cases, were directly associated with in-hospital mortality.

From a surgical standpoint, mechanical complications such as nonunion, implant loosening, fracture dislocation, and re-fracture were noted. At least four patients required re-reosteosynthesis, and in more severe cases, revision surgeries with endoprosthetic replacement were performed. One study reported the use of both an RMS system and endoprosthesis in a single patient with repeated failures.

Mortality was substantial across the studies. At least 9 studies explicitly reported death events, with early mortality (within 3 months) observed in several cohorts. One study documented 5 deaths within 3 months and others within 5 years, while another reported 9 deaths within the first year, including 5 at 30 days, 2 at 3 months, and 2 at 12 months. One cohort noted 10 deaths within one year, and another reported 4 deaths at 24 months. A particularly detailed analysis showed 9 deaths in the short nail group (3 within 4 weeks and 6 within 1 year), and 3 deaths in the long nail group (1 within 1 month and 2 within 1 year).

Functional recovery also appeared to influence prognosis. In one study, the mortality rate among patients who were non-ambulatory at final follow-up was significantly higher than in those who regained walking ability (65.7% vs. 12.5%; p < 0.01), suggesting that mobility outcomes are strong predictors of survival (Table 8).

Table 8.

Complications

First author	Infection	Other complications	Further treatments?	Death	Time to death (weeks)
Aguado-Maestro et al. [1]	1(+ 2 covid)	1 atypical fracture, 1 popliteal thrombosis, 1 delay of consolidation	1 re-reosteosynthesis	NA	83% 5y
Luca Bianco Prevot et al. [31]	2	1 Acute kidnei failure, 1 loosening and re-surgery	1 re-reosteosynthesis	9	5 died at 30 days, 2 at 3 months, 2 at 12 months
Wulbrand et al. [41]	2 SSI	1 hematoma, 3 lower urinary tract infections, 2 delirium, 1 pneumonia, 1 acute on chronic kidney disease, 1 myocardial infarction	N/A	N/A	10 deaths at 1y
Manuela Poroh et al. [30]	2	2 non union	N/A	1	N/A
Fernando Bidolegui et al. [6]	3 SSI	2 TVP, 1 pneumonia, 1 TEP	N/A	N/A	N/A
Vilar-Sastre et al. [21]	9	2 mechanical failures	2	8	5 deaths within 3 months, remaining within 1 year
Halonen et al. [22]	1 SSI	N/A	N/A	4	24 months
JiříSkála-Rosenbaum et al. [37]	0	0	0	N/A	N/A
Müller et al. [24]	0	1 hematoma, 1 fracture disclocation	N/A	6	2 during first week
Henry Goodnough et al. [15]	0	Delirium, urinary infection/retention/sepsis, pneumonia, atrial fibrillation, NSTEMI, upper GI bleeding, ICU for hypotension	N/A	12 (9 in short nail)	4 deaths during first 4weeks e 8 during the 1 year
Bjørgul et al. [7]	0	1 re-refracture + loosening e 1 re-refracture	1 implant removal + hemiarthroplasty e 1 re-reosteosynthesis	N/A	N/A
Osnes et al. [27]	0	1 re-refracture	1 re-reosteosynthesis	0	0

Discussion

Peri-implant fractures represent a real challenge for orthopedic surgeons, both due to the rarity of the event (incidence about 1.7%) and the difficulties in managing the patient and the type of treatment, which is not always well-defined [8].

Our review shows that fracture patterns can be classified into three main types (Type A, B, C), and surgical strategies can be guided by this classification. Tip fractures (Type A) are best managed with exchange or longer nails; fractures around the nail (Type B) with plating or nail revision; and distal fractures (Type C) with distal femoral plates or long nails.When reported, peri-implant fractures were most frequently associated with low-energy trauma such as falls from standing height (approximately 65%), while mechanical factors including stress risers at the tip of the nail (15%) and implant malposition or inadequate reduction (10%) were identified in some cases. Many studies, however, did not report the fracture mechanism, reflecting a significant gap in the literature. Despite heterogeneous reporting, peri-implant fractures treated surgically achieved high union rates (weighted average 93.7%), although complications and mortality remained considerable, particularly in frail patients or with delayed surgery. These findings underscore the importance of standardized reporting, fracture classification, and surgical recommendations tailored to fracture type to improve clinical decision-making and patient outcomes.

Reviewing the results of our study, it is evident that the average age, considering all studies, was 78.4 ± 9.1 years, highlighting a predominance of elderly patients, particularly those over 70 years old (72% of cases), with the female sex being the most affected. These results coincide with data from the literature [8, 18].

Obesity was found in 33% of patients with BMI > 30, which was also associated with an increased rate of complications. Obesity increases the risk of peri-implant femoral fractures due to mechanical stress, increased body weight, changes in gait, and increased general inflammatory status. Obesity also contributes to a greater delay in bone healing compared to those with normal BMI [36].

The average time between the first fracture and the diagnosis of a peri-implant fracture varied significantly between studies, with reported averages ranging from 8 to 13 months after the primary surgical intervention. 14.2% of fractures occurred within the first 6 months after the initial surgery, mainly in patients with early mechanical failures, generally due to "stress risers" that form in regions where stress forces exceed those of the surrounding material. These forces mainly develop at the tip of the nail due to micromovements that weaken the femoral cortex, exposing it to a higher risk of fractures [13, 28].

From an anesthesiological and patient management perspective, the ASA classification was mainly used, with most patients classified in classes II and III [19]. This was due both to the age of the patients and associated risk factors such as smoking, which ranged from 10% to a maximum of 33%.

Smoking is one of many factors predisposing to postoperative complications. Although smoking affects various organs (heart, lungs, blood, immune system, and nervous system), the most evident perioperative morbidity is pulmonary in origin, which should be avoided, especially in bedridden patients [16].

14.1% of the sample were on oral anticoagulants, while most did not take them. In the perioperative period, as per guidelines, a significant proportion of patients received low-molecular-weight heparin (LMWH). LMWH is frequently administered for the prophylaxis of thromboembolic complications. The choice to use LMWH is supported by its predictable pharmacokinetics, reducing the need for frequent monitoring [29].

All patients in the study were treated with an antegrade intramedullary nail. Intramedullary nailing with a cephalomedullary nail remains the gold standard for pertrochanteric fractures [25]. Additionally, as an intramedullary implant, it improved the safety of approaches to fractures involving the lateral wall and lesser trochanter, as well as oblique inverse fractures (classified as AO 31-A2 and AO 31-A3). This approach remains the most commonly used treatment for peri-implant fractures [11, 35]. About 53.7% of patients did not specify the implant type, highlighting a lack of standardization. Only 132 cases had quantifiable data on nail length (< 200 mm or > 200 mm), with the choice of nail length depending primarily on fracture stability. Although most literature suggests no significant difference in peri-implant fracture risk between short and long nails [39], our analysis showed that delayed surgery was associated with higher mortality (21.6% vs 9.3% for early treatment).

Patients operated within 48 h showed better results and a lower complication rate compared to others. This is because the risks associated with bedridden status, which can increase the mortality rate, are significantly reduced [2]. The most followed surgical indication was intramedullary nailing over plate and screw fixation (82% vs. 18%). Intramedullary nailing has the advantage of being a faster procedure, with less blood loss and a lower infection risk [33].

Regarding healing rates, the results are good, with a healing rate approaching 94%. The consolidation time was slightly longer for intramedullary nailing compared to plate osteosynthesis. Healing times for fractures were longer in osteoporotic patients, possibly due to the altered biomechanical properties of osteoporotic bone, which not only has reduced bone mass but also decreased cortical thickness, increased cortical porosity, trabecular disorientation relative to the direction of load, and changes in the bone matrix composition [10]. The complication rate, according to the results, ranged from 3% to 25.6%, although the nonunion rate was less than 5%. This can be partly explained by factors such as advanced age, weight-bearing restrictions, and osteoporosis. A noteworthy finding was the implant failure rate of about 9.8%, with 4.8% requiring further surgery. It is important to highlight that some studies did not report all complications in detail, which may have contributed to the variability of the data presented. In conclusion, little is known about non-periprosthetic peri-implant fractures. Most of them occur around a previous implant and are mainly related to biomechanical conflicts between the distal nail design and its tip [42]. Regarding fixation, the best idea would be to use a long nail that spans the entire femur or is at least longer than the previous implant, allowing for a stable fixation. Although using a longer implant may increase the risk of bleeding and morbidity, it is often the best option.

Further comparative studies including a larger number of cases, possibly with direct comparisons between fixation methods, would be useful to clarify the actual differences in clinical outcomes and complication rates.

Study limitations

This systematic review presents several limitations that should be considered when interpreting its findings. First, the included studies were heterogeneous in terms of their designs, sample sizes, and patient characteristics, which may affect the generalizability of the results. While we included a range of study designs, including both retrospective and prospective studies, the lack of high-quality randomized controlled trials (RCTs) limits the ability to draw firm conclusions about the best management strategies for "around the nail" fractures.

Additionally, the quality of the studies included in this review varied, with many studies receiving relatively low MINORS scores, suggesting potential biases in study design or reporting. While we made efforts to minimize bias through a rigorous data extraction process, the retrospective nature of many of the studies means that confounding factors, such as preoperative comorbidities, surgical technique variations, and post-operative care differences, could influence the results.

Another limitation is the variability in follow-up periods across studies. Although most studies reported a minimum follow-up of six months, the range of follow-up periods was wide, and some studies did not report long-term outcomes. The lack of standardized outcomes, such as specific functional scores or complication rates, further complicates comparisons between studies.

Future research should aim to conduct high-quality RCTs with standardized outcome measures and longer follow-up periods to provide more definitive evidence on the management of "around the nail" fractures.

Conclusion

Peri-implant femoral fractures around intramedullary nails remain a complex challenge with no universally accepted treatment strategy and classification. Lateral locked plating, nail revision and arthroplasty each have advantages and limitations, with the choice depending on fracture pattern, implant stability, and patient factors. Current evidence suggests high union rates but variable complication and mortality rates, particularly in elderly patients with comorbidities. Nevertheless, the issue regarding nail length remains debated. While long nails appear to offer biomechanical advantages and reduce the risk of peri-implant stress risers, short nails continue to attract interest because of their easier implantation and shorter operative times. The redesign of short nails to improve their biomechanical profile could also represent a future perspective in this field. Intermediate-length nails might represent a compromise between the advantages of short and long nails, although current evidence is still limited [40].

Despite advancements, optimal management remains debated due to a lack of high-quality comparative studies. Further research is needed to establish standardized, evidence-based guidelines to improve outcomes in this challenging clinical scenario.

Abbreviations

ASA

American Society of Anesthesiologists

BMI

Body mass index

CCI

Charlson Comorbidity Index

DHS

Dynamic hip screw

DOACs

Direct oral anticoagulants

FNF

Femoral neck fracture

IMN

Intramedullary nailing

MINORS

Methodological index for non-randomized studies

PFF

Proximal femur fracture

PF

Pertrochanteric fracture

PPIF

Periprosthetic femur fracture

PRISMA

Preferred reporting items for systematic reviews and meta-analyses

SPSS

Statistical Package for the Social Sciences

Author contributions

All authors have contributed to the conception and design of this study, acquisition of data, in drafting the article, in its revision, and all the authors approved the final draft of the submitted article.

Funding

This research received no external funding. None of the authors received any funds or has any financial interests to disclose.

Data availability

All the data we analysed and tables we compiled are available for any clarification.

Declarations

Competing interests

The authors declare no competing interests.