Abstract
Purpose
Femur fractures are among the most common fractures treated surgically, representing a significant challenge for the orthopedic surgeon. Peri-implant femoral fractures (PIFFs) represent a rare complication of the surgical treatment. It is necessary to pay attention during osteosynthesis, evaluating not only the fracture site but the entire femoral skeletal structure, the characteristics of the fracture, the health comorbidities, and the risk of malunion and pseudarthrosis. There are few studies on the incidence, treatment, and outcomes of PIFFs near osteosynthesis. This study aimed to investigate PIFF after osteosynthesis of femoral fractures and evaluate the mortality after surgery and the morbidity associated with these types of fractures.
Methods
A retrospective cohort study was carried out at the IRCCS Galeazzi Orthopedic Institute, Milan, Italy, between January, 2017 and December, 2022. Inclusion criteria were the presence of a femur fracture around an intramedullary nail to treat a previous fracture, follow-up ≥ 12 months, and patients aged ≥ 65 years. Exclusion criterion was intraoperative periprosthetic fractures. The data were expressed as frequency and percentage. Continuous variables were expressed as mean ± standard deviation or median and range.
Results
Overall, 25 patients were enrolled (88.0% female) and the mean age was 84.5 years (range of 70 – 92 years). There were 20 patients having type B PIFF and 5 having type C. In 22 patients, multiple comorbidities were found with an average Charlson comorbidity score of 5.5 and the mean time to peri-implant fracture was 38 months. After surgery, 1 patient (4.0%) presented renal failure, 1 (4.0%) needed removal surgery for their loosening, and 2 (8.0%) presented surgical site infection. Nine patients (36.0%) died within 1 year with a mortality rate of 20.0% at 30 days, 8.0% at 3 months, and 8.0% at 12 months.
Conclusions
PIFFs in elderly patients are associated with high short-term mortality and morbidity, so careful planning for primary fracture surgery and patient awareness to ensure prolonged compliance and a healthy lifestyle are essential for prevention.
Keywords: Complication, Hip fracture, Internal fixation, Peri-implant femoral fracture, Stress riser, Mortality and morbidity, Informed consent
1. Introduction
Femur fractures are among the most common fractures treated surgically and represent a significant challenge for the orthopedic surgeon. The primary goal of surgical treatment is to achieve anatomical reduction and absolute stability that resists deforming forces, minimizes any interfragmentary movement, and facilitates the healing process through bone callus formation. Early functional rehabilitation is pivotal as well. The management of displaced or unstable fractures is complex and the optimal treatment is not yet clear, with major implications for surgical indication and appropriateness. Furthermore, in addition to the characteristics of the fracture, other important factors such as biological age, bone quality, patient's functional expectations, and the personal experience of the surgeon must be considered when choosing the treatment. This has an impact on the information patients receive about the risks and benefits, and thus on the informed choice of treatment. The timing of surgery is critical, taking into account the patient's functional goals, fracture characteristics, comorbidities, bone quality, and risk of malunion and pseudoarthrosis. A peri-implant femoral fracture (PIFF) is defined as a femoral fracture in the presence of a pre-existing non-prosthetic implant1 and represents a rare complication of the fracture surgical treatment. Therefore, PIFF and periprosthetic fractures (PPF) must be evaluated separately, as they are different entities.2 The incidence of PIFF has progressively increased due to the increase in patients undergoing fixation of primary femur fractures and the increase in life expectancy of these patients. While recognizing the evolution of engineering science in implant design, several factors may represent a potential risk of femoral fractures after implant placement, due to changes stress riser effect, resistance to elastic deformation, and poor bone quality inherent to the process of aging.3 Peri-implant stress riser fractures are the result of cortical defects (holes), changes in stiffness, sharp corners, and cracks (fracture lines), which occur in regions where stress forces are greater than those of the surrounding material.4 Most riser stress fractures are related to technical errors (iatrogenic causes) and are difficult to manage.5 The treatment of PIFFs can be complicated by the low bone mass, advanced age of patients, and problems related to the possibility of obtaining a stable and adequate synthesis. It is of fundamental importance to plan an adequate therapeutic strategy for the treatment of PIFF, which must take into consideration multiple factors, such as the healing state of the original fracture, the type of implant, the time elapsed since the first fracture, and the position of the acute fracture with the implant and bone quality.6
Furthermore, these types of fractures typically occur in elderly subjects, with multiple pathologies that cause a significant increase in mortality and morbidity. There is little information in the medical literature that provides recommendations for the appropriate treatment of PIFFs in the elderly population.
The purpose of this article is to describe our experience with the treatment of PIFFs in the elderly using fixation and to evaluate the 1-year mortality after surgery and the morbidities associated with these types of fractures.
2. Methods
A retrospective cohort study of the patient's medical records, operating records, and radiographs was performed at the IRCCS Galeazzi Orthopedic Institute, Milan, between January, 2017 and December, 2022. Informed consents were obtained from the patients involved in the study. The criteria for patient inclusion were the presence of a femur fracture that occurred around an intramedullary nail implanted to treat a previous fracture, a minimum follow-up of 12 months after surgery, and an age greater than 65 years. Further, the exclusion criterion was the presence of intraoperative periprosthetic fractures.7 From the patient records, demographic data, patient comorbidities, type of fracture, and hemoglobin values on admission, on the first postoperative day, and at the time of discharge were collected. The Charlson co-morbidity index score8 was calculated for each patient, which is a validated tool for predicting 1-year mortality. A score is calculated based on the comorbidities and age of the patients. The type of anesthesia practiced, the American Society of Anesthesiologists (ASA) class, and the type of operation performed were retrieved from the operating registers. Fractures were classified according to the classification system for PIFFs: type A fracture occurs in the trochanteric region or the femoral neck, type B fracture occurs around the implant, type C fracture is distant from the implant, and types D and E fractures are not relevant to this study.9 All radiographs were graded by 3 authors. If there was uncertainty about the classification, a consensus decision was made. Finally, 25 patients were selected for the study. Data was analyzed by using SPSS Statistics for Windows, version 23.0 (IBM SPSS Statistics for Windows, version 23.0. Armonk, NY: IBM). Continuous variables were expressed as mean ± standard deviation (SD) or median and range according to their distribution. Categorical variables were expressed as frequency and percentage.
3. Results
Among 25 patients selected in the retrospective study, 2 were men and 23 were women, with an average age of 84.5 years (range of 70 – 92 years) (Table 1).
Table 1.
Characteristics of the samples.
| Variables | Values |
|---|---|
| Age (year), median (range) | 84.5 (70 – 92) |
| Sex, n (%) | |
| Men | 2 (8.0) |
| Women | 23 (92.0) |
| Peri-implant fracture classification, n (%) | |
| Type B | 20 (80.0) |
| Type C | 5 (20.0) |
| Charlson comorbidity score, n (%) | |
| 0 – 1 | 0 (0) |
| 2 – 3 | 1 (4.0) |
| 4 – 5 | 16 (64.0) |
| 6 – 7 | 6 (24.0) |
| > 7 | 2 (8.0) |
| ASA class, n (%) | |
| ASA I | 0 (0) |
| ASA II | 11 (44.0) |
| ASA III | 14 (56.0) |
| ASA IV | 0 (0) |
| Fracture treatment, n (%) | |
| Plate and screws | 21 (84.0) |
| Intramedullary nail exchange | 4 (16.0) |
| Hemoglobin (g/dL), mean ± SD | |
| Preoperative | 11.4 ± 1.4 |
| Time of transfusion | 8.3 ± 0.8 |
| At discharge | 10.3 ± 0.8 |
| Median units of blood transfused (units), median (range) | 3 (2 – 6) |
| Complications, n (%) | 4 (16.0) |
| Surgical site infection | 2 (8.0) |
| Synthesis means loosening and re-surgery | 1 (4.0) |
| Medical (acute renal failure) | 1 (4.0) |
| Mortality, n (%) | 9 (36.0) |
| At 30 days | 5 (20.0) |
| At 90 days | 2 (8.0) |
| At 1 year | 2 (8.0) |
ASA: American Society of Anesthesiologists; SD: standard deviation.
Overall, 13 fractures were found on the left side and 12 on the right side. All fractures were the result of a low-energy traumatic event, usually falling from the foot. Twenty fractures occurred around the fixation device (type B), while 5 fractures occurred distal to the fixation device (type C). In our case series, a bimodal distribution of femur re-fractures was observed (Fig. 1).
Fig. 1.
Distribution of PIFF cases about the months elapsed between them and the first fracture.
PIFF: peri-implant femoral fracture.
Moreover, 22 patients had multiple comorbidities, including arterial hypertension, diabetes, and cognitive impairment. Three patients had a history of previous breast cancer in follow-up at the time of the fracture. Charlson comorbidity score and ASA class are reported in Table 1. None of the patients were smokers or alcohol users.
Concerning the first femur fracture treatment, all the cases examined underwent surgery for reduction and synthesis with an intramedullary nail. Twenty patients were treated with an antegrade intramedullary nail implant 180 mm diameter 11 mm (Gamma® 3 model, Stryker, Kalamazoo, MI, USA), while 5 patients were treated with an antegrade intramedullary nail 270 mm diameter 11 mm (Gamma® Long model, Stryker, Kalamazoo, MI, USA). The time elapsed between the first fracture fixation operation and the onset of the new peri-implant fracture was on average (38.0 ± 57.1) months.
All patients were treated for PIFF by the same operator. The average surgical time was (128.6 ± 53.4) min and all patients received spinal anesthesia. In 21 patients, internal fixation with plate and screws was performed (an NCB® plate, Zimmer in 16 cases, a Cable-Ready® Greater Trochanteric Reattachment plate, Zimmer in 4 cases, and an Axsos 3 plate, Stryker in 1 case) without removal of the intramedullary nails (Fig. 2, Fig. 3, Fig. 4).
Fig. 2.
(A) Anteroposterior X-ray of the left thigh showing a peri-nail type C fracture; (B) Postoperative anteroposterior X-ray of the left thigh showing fracture fixation with a plate and screws, an interfragmentary screw, and metallic cerclage.
Fig. 3.
(A) Anteroposterior X-ray of the right thigh showing a peri-nail type C fracture; (B) Postoperative anteroposterior X-ray of the right thigh showing fracture fixation with a plate, screws, and an interfragmentary screw.
Fig. 4.
(A) Lateral X-ray of the left thigh showing a peri-nail type B fracture; (B) Postoperative anteroposterior X-ray of the left thigh showing fracture fixation with a plate and screws, an interfragmentary screw, and polyethylene cerclage.
In 4 cases (16.0%), the intramedullary nail was removed and an antegrade 340 mm diameter 11 mm intramedullary nail was reimplanted (Gamma® Long model, Stryker, Kalamazoo, MI, USA) (Fig. 5).
Fig. 5.
(A) Antero-posterior X-ray of the thigh showing fracture of the femur distal to the apex of the nail; (B) Antero-posterior x-ray of the thigh showing fixation of the fracture with intramedullary nail Gamma® Long model, Stryker.
In all patients in whom the plate was implanted, a standard lateral approach to the femur was used. Having reached the fracture site, we proceeded with the reduction with the assistance of fluoroscopy with a C-arm. In the postoperative course, all patients needed concentrated red blood cell transfusion due to anemia (an average of 3 units per patient, with a range of 2 – 6 units). The mean hemoglobin values in the preoperative period, the mean hemoglobin values at the time of transfusion, and the average values at discharge are reported in Table 1. Immediately after the operation, following a specialist physiatry evaluation, an individual rehabilitation program was planned, aiming at restoring joint function, muscle tone-trophism, and gait pattern through ambulatory training exercises. Initially, all patients were allowed a grazing load, while progressive loading was undertaken at 4 weeks, allowing total loading at approximately 6 weeks. All patients underwent periodic clinical and radiographic follow-up. For some of them, given the concomitant Sars Cov2 pandemic period which disrupted the regular carrying out of outpatient activities and the planning of clinical-instrumental checks, telematic monitoring with caregivers was necessary to overcome the objective organizational difficulties.10,11
There were some postoperative complications. One patient developed acute renal failure which, however, did not require dialysis therapy. Two patients developed a surgical site infection with subsequent antimicrobial and surgical wound revision, without requiring the removal of the synthesis means. One patient loosening of the fixation devices was observed 1 month later, which required a new surgical approach for their removal. One year after the operation, an overall mortality of 36.0% was found (9 patients out of 25 died), 20.0% (5 patients) within 30 days of surgery, 8.0% (2 patients) within 3 months, 8.0% (2 patients) within 12 months (Table 1).
4. Discussion
To the best of our knowledge, this retrospective study reports one of the largest series of elderly patients treated for PIFFs. This topic is increasingly investigated, but currently, few data are available on management and outcomes. The study shows that these fractures present a high number of complications and a high mortality. PIFFs require an independent evaluation compared to peri-prosthetic femur fractures as the populations are different. In fact, with the limitations of including only elderly patients, if comparing our findings with those of Jennison et al.,12 we observe a higher average age of 84.5 years vs. 80.7 years. Moreover, it can be observed that our patients had an average Charlson comorbidity score of 5.5 compared to 4.5. Mortality in our series was 20.0% at 30 days and 36.0% at 1 year after surgery. This finding is significantly higher than the data for peri-prosthetic hip fractures in which the 30-day mortality is 3.3% and the 12-month mortality is 13.4%, as reported in a systematic review conducted by Lamb et al.13 The increased mortality in our case series may be attributable to higher age, increased ASA, and an increased Charlson comorbidity index, compared to Bidolegui et al.2 although the refracture time is longer. Interesting is the comparison with 30-day mortality data for primary femur fracture nationwide, reported in 2022 in the National Outcomes Plan (Piano Nazionale Esiti, PNE) by the National Agency for Regional Health Services (Agenzia Nazionale per i Servizi sanitari regionali, AgeNaS), that was 6.26% (5th – 95th 6.08 – 6.44)14 and with the 1-year mortality of 16.6%.15,16 This also concerns the standards of health facilities and professionals and the time of surgery. To date, there are no specific treatment algorithms for femoral implant fractures, just as there is no dedicated classification of this type of fracture.17 For this reason, the treatment is also not standardized. In this way, the therapeutic choice is dictated by the surgeon's experience, certainly tailored to the complexity of the patient and the comorbidities encountered. Treatment of isolated PIFFs should take into consideration the location of the fracture, the stability of the implant, and the quality of the surrounding bone stock. The surgical strategy should include a thorough understanding of the biology of the underlying bone segment, as well as the biomechanics of the existing implant and modern fixation principles. It is also essential to consider whether or not the fracture previously treated with an intramedullary nail has healed. All cases in our series presented a new fracture that occurred following the healing of the previous one. The use of an intramedullary device certainly represents the treatment choice for femur fractures, although it is known that it can alter the biomechanical properties of the bone and increase the risk of subsequent periprosthetic fractures.18 In our case series, we observe a bimodal distribution of PIFF (Fig. 3), with a peak of onset close to the first femoral fracture surgery and a second peak several years after the first fracture. A possible explanation for short-time fracture is due to some peri-implant micromovements, which cause the transfer of stress to the tip of the implant and therefore can induce a new fracture, even with mild traumatic forces, as reported by Norris et al.19 Fractures that occur later than the primary traumatic event may be related to a progressive alteration of the bone mineral quality of patients with increasing age, which associated with an abnormal modulus of elasticity of the femur due to the intramedullary device implanted increases the risk of new fracture. Unfortunately, data on bone mineral density were not available or reported for all patients, also because these are not elective surgeries. The definitive surgical intervention must guarantee adequate stability of the fracture site, as well as correct bone alignment, to allow the most optimal functionality.20
PIFFs can cause several significant complications and morbidities, with consequent disability: persistent pain, gait impairment, functional limitations of the hip and/or knee, infections, bleeding, and wound healing problems. There are several risk factors associated with PIFFs. Elderly people have a greater risk of PIFFs, due to the concomitant osteoporotic condition.21 The quality of the bone surrounding the implant can influence the risk of peri-implant fractures and further studies investigating the risk of fracture in the elderly population after implants are needed.22 Some metabolic diseases, such as diabetes and hyperthyroidism, can affect bone health and increase the risk of PIFFs.23, 24, 25 Significant trauma, such as a fall or accident, could be an external cause of PIFFs. Obesity can place excessive load on the orthopedic implant and surrounding bone, increasing the risk of peri-implant fractures, to be acknowledged for verticalization timing.26 Risk factors such as cigarette smoking, alcoholism, and lack of physical activity can affect bone health and increase the risk of PIFFs. Therefore, it is worth emphasizing that, in the absence of codified scientific references of good practice even with a good surgical technique of implantation, peri-implantation refracture sometimes occurs as a function of the integration of numerous risk factors, some of which cannot be controlled a priori, and in any case with undefined predictivity. So, implant failure and fracture risk remain difficult to assess.27,28
A correct preoperative evaluation, including bone density analysis or indication for bone mineral density testing, radiographic examination, and identification of specific risk factors such as comorbidities, can help prevent PIFFs, thus reducing re-surgery and the mortality increase.29,30 Drug therapies, vitamin and mineral supplementation, and lifestyle changes are also to be considered.31 This assessment helps identify high-risk patients and make informed decisions about the most appropriate implant type and surgical technique.32 From the side of the orthopedic surgeon, adequate planning, and execution of orthopedic surgery, including the choice of appropriate implants, correct positioning, and adequate stability can reduce the risk of PIFFs. Surgical errors during implantation or postoperative management can increase the risk of PIFFs, so orthopedic surgeon training is likewise pivotal. A well-structured postoperative rehabilitation program, including muscle strengthening exercises, gradual increase in physical activity, and regular monitoring can help improve bone healing and reduce the risk of fractures.32 Some complications related to orthopedic surgery, such as infection or implant failure can directly increase the risk of PIFFs.33 Regarding infections, it should be noted that the infection could also result from the complex interaction of multiple factors: pathogens with biofilm, devices, and weakness of the host.34 Timely management of these complications can help reduce the likelihood of fractures. Regular monitoring of patients who have undergone orthopedic implant surgery can help detect signs of deterioration or problems early, allowing timely intervention to prevent or manage peri-implant fractures.35,36
It is important to underline that PIFFs can occur even in low-risk patients, to whom proper information must be provided, to ensure their active participation in load, rehabilitation, and living habits. The management of peri-implant fractures requires an individualized approach, based on the assessment of specific risks and the best available clinical practices.37, 38, 39
There are some limitations in this study, such as the retrospective nature of this study. Incomplete medical records could have determined the exclusion of some cases treated during the reference period. Moreover, the same reason limited bone mineral density reporting.
In conclusion, distal femur peri-implant fractures are becoming an increasingly common orthopedic pathology due to the increase in the average age of the population and life expectancy. They occur in a complex group of patients and determine high mortality and complication rates, such as infections, late wound healing, and re-implant mobilization/relaxation. However, it is important to note that the specific mortality rate associated with these fractures relates to several factors, such as age, patient general health status, bone health, surgeon experience, time to re-fracture, and re-surgery. Accurate preoperative evaluation in case of femur fracture allows the identification of patients at higher risk for PIFF, with the possibility of taking preventive measures both in the surgery phase and the immediate postoperative period, thinking about loading, rehabilitation, and pharmacological supplementation. Moreover, a comprehensive evaluation allows informed decision-making about the most appropriate type of implant and surgical technique for each patient, in the absence of defined references of good clinical practice. Equally important in treatment outcome and mortality are therefore the information and compliance of the patient on the correct behaviors in the rehabilitation phase in the short term, and on lifestyle habits in the long term.
CRediT authorship contribution statement
Luca Bianco Prevot: Conceptualization, Data curation, Investigation, Methodology, Supervision, Visualization, Writing – original draft, Writing – review & editing, Formal analysis. Vittorio Bolcato: Conceptualization, Investigation, Supervision, Writing – original draft, Writing – review & editing. Stefania Fozzato: Data curation, Methodology, Writing – review & editing. Riccardo Accetta: Investigation, Validation, Writing – review & editing. Michela Basile: Investigation, Resources, Software, Validation, Writing – review & editing. Livio Pietro Tronconi: Methodology, Project administration, Writing – original draft. Giuseppe Basile: Conceptualization, Data curation, Investigation, Methodology, Project administration, Supervision, Validation, Writing – original draft, Writing – review & editing.
Ethical statement
Informed consent was obtained from the patient involved in the study. Written informed consent has been obtained from the patient to publish this paper.
Funding
Nil.
Declaration of competing interest
The authors declare no conflict of interest.
Footnotes
Peer review under responsibility of Chinese Medical Association.
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