Proximal femur replacement in oncologic lesion: hemiarthroplasty vs total hip arthroplasty-a multicentric retrospective study.

Introduction

When discussing proximal femur replacement, we are referring to a reconstruction procedure that occurs following the removal of the proximal femur, whereby part or the entire joint is substituted with a mega prosthesis. Historically, a diagnosis of neoplasm in the proximal femur often necessitated amputation, which was perceived as the sole method to achieve oncological radicality [ 1 ]. However, current reconstructive techniques utilizing mega prostheses have emerged, allowing for the avoidance of amputation and the preservation of the limb [ 2 ]. This innovative approach is termed “limb salvage surgery,” which has successfully diminished the necessity for amputation to less than 10% of cases [ 3 ]

Proximal femur replacements are primarily categorized into two principal types: hemiarthroplasties (modular mega- endoprostheses, HA) and total hip arthroplasties (THA), the latter of which involves the substitution of the acetabular cup [ 4 ].

Initially, complications associated with mega prostheses were classified into mechanical and non-mechanical types [ 5 ]. Subsequently, they were further categorized into five distinct classifications based on the mechanism of failure [ 6 ]. The incidence of mechanical complications fluctuates between 5 and 48%, with aseptic loosening being the most frequently encountered issue. Nevertheless, the prevalence of these complications is on the decline due to the advent of newer and more robust modular designs [ 7 – 9 ]. Non- mechanical complications encompass infections, surgical wound necrosis, and tumor recurrence, with infection-related failure rates ranging from 2 to 12% [ 10 , 11 ]. These complications are prevalent in orthopedic oncology surgery, as the substantial implants often lack sufficient soft tissue coverage following extensive excision, particularly in patients who are immunosuppressed and may experience malnutrition as a consequence of chemotherapy and local irradiation [ 12 ]. The introduction of advanced materials and techniques, such as silver-coated implants, is anticipated to enhance these outcomes; however, non-mechanical complications persist as the most common concern and are likely to remain a significant issue in the foreseeable future [ 13 , 14 ]. In this study, we specifically report findings related to patients with metastatic conditions. It is crucial to recognize that the functional outcomes of proximal femur replacement vary based on whether the patient presents with a primary neoplasm or metastasis, as demonstrated by the research conducted by Potter et al. [ 15 ]. Our aim was to assess the complications and functional outcomes associated with the application of mega prostheses, comparing HA to THA, in order to ascertain which approach yields superior results for patients with proximal femur neoplasms.

Materials and methods

Patients selection

Patients suffering from primary bone tumors or bone metastases that affect the proximal femur underwent en-bloc resection, which was subsequently followed by either modular endoprosthetic reconstruction or total hip arthroplasty in conjunction with modular prosthetic reconstruction. This study conducted a retrospective analysis of the outcomes observed across two prominent orthopedic oncology centers.

All participants involved in the study were duly contacted for evaluation, and supplementary data were obtained from the hospital’s records.

Inclusion criteria

The study encompassed all patients aged 18 years and older who underwent mega prosthesis reconstruction of the proximal femur, specifically from the greater trochanter to the subtrochanteric area, for neoplastic disease during the period from 2015 to 2022. Participants were required to have a minimum follow-up duration of three months.

Exclusion criteria

Patients were excluded if they had a follow-up period of less than 3 months or if they underwent distal or total femur resection or reconstruction.

In the present study, Group A was administered either cementless or cemented mega prostheses, whereas Group B underwent total hip arthroplasty in conjunction with mega prostheses.

The surgical complications assessed encompassed wound dehiscence, deep infection, implant dislocation, deep vein thrombosis, periprosthetic fracture, and intraoperative blood loss (Table 1 ). Table 1 Inclusion and exclusion criteria Inclusion Exclusion Age > 18 y.o. at surgery time < 18 y.o. at surgery time Type of surgery Proximal femur reconstruction Distal femur or total femur reconstruction Follow up > 3 months < 3 months

Surgical technique

An orthopedic oncology center employed the following surgical methodology: general anesthesia was administered in all instances. Each patient received 2 g of intravenous Cephazoline as antibiotic prophylaxis prior to surgery, unless contraindicated [ 16 ]. A urinary catheter was inserted into all patients and subsequently removed within 72 h post- surgery. Patients were positioned in the lateral decubitus orientation, and a lateral approach was utilized during the procedure. Following bone exposure, an en- bloc resection was executed, and a cementless silver- coated mega prosthesis was implanted in accordance with the manufacturer’ s protocol (Mutars, Implantcast) [ 17 ] (Fig. 1 ). In two specific cases, the decision was made to cement the stem based on the surgeons’ preferences, reflecting varying levels of experience, along with the condition of the bone. The surgical procedure was concluded with myodesis utilizing a Trevira Tube © (Implantcast; GmbH, Buxtehude, Germany) [ 18 ]. Whenever an acetabular replacement was deemed necessary, a dual mobility acetabular system was employed, selected for its capacity to accommodate screws, thereby ensuring enhanced fixation. This selection also depended on the surgeon’ s preferences, in addition to the patient’ s age and life expectancy. One intra- articular closed- suction drainage system was installed and subsequently removed 48 h following the surgical intervention. Fig. 1 MUTARS Implantcast, proximal femur implant

The second oncology center adopted a similar approach: general anesthesia was administered in all cases. Each patient received antibiotic prophylaxis prior to surgery in accordance with the hospital’ s protocol, barring any contraindications. Patients were positioned in a lateral decubitus position, and a lateral approach was employed. After bone exposure, an en- bloc resection was performed, and either a cementless or cemented endoprosthesis was implanted following the manufacturer’ s guidelines (Megasystem C Link) [ 19 ] (Fig. 2 ). No patients underwent acetabular replacement. An intra- articular closed- suction drain was positioned and subsequently removed 48 h after the operation. All patients adhered to a uniform post- operative rehabilitation protocol; 48 h post- surgery, patients were seated with their feet positioned outside of the bed; after 72 h, patients were permitted to progressively bear weight with the assistance of a walker frame. The achievement of independent ambulation was realized within a duration of two months. Standard total hip precautions were strictly enforced for a period of three months. Patients underwent regular follow- up assessments at two and four weeks post- surgery, which were subsequently followed by evaluations every three months throughout the initial two years, and then annually thereafter. Commencing four weeks post- surgery, radiographic imaging was performed during each clinical evaluation. All patients strictly adhered to the protocol. Fig. 2 Megasystem C Link, proximal femur implant

Clinical evaluation

Anthropometric and anamnestic data were collected, along with information regarding the type of primitive tumor, the presence of impending or pathological fractures, and the duration of surgery. Beginning at the three-month mark and continuing at each follow-up appointment, self-assessed questionnaires were administered to all patients at the clinic to evaluate their postoperative functional outcomes. Two distinct scoring systems were employed: the Harris Hip Score (HHS) and the Musculoskeletal Tumor Society (MSTS) score [ 20 , 21 ]. The HHS is specifically designed to assess hip function and focuses on four key parameters: pain, function (encompassing ambulation and daily activities), range of motion, and the absence of deformity. This score ranges from 0 to 100, with higher scores indicating superior functional outcomes. The pain component contributes up to 44 points, function contributes up to 47 points, range of motion contributes up to 5 points, and deformity contributes up to 4 points. Thus, a higher score is indicative of reduced pain and enhanced functional capacity in daily activities. Conversely, the MSTS score is tailored for musculoskeletal tumors and evaluates six parameters: pain, function, emotional acceptance, usage of supportive devices, walking ability, and gait. Each parameter is rated on a scale from 0 to 5, where 0 represents the lowest score and 5 represents the highest. The MSTS score emphasizes the extent to which the patient is capable of adapting and functioning following tumor surgery. Collectively, these two scoring systems furnish a comprehensive overview of the patients’ physical recovery, residual functionality, and quality of life post-surgery. The HHS provides a detailed analysis of hip-specific outcomes, while the MSTS encompasses anthropometric and anamnestic data, insights regarding the primitive tumor, information concerning potential or existing pathological fractures, and the duration of surgery.

Statistical analysis

Data analysis was conducted utilizing Microsoft Excel and GraphPad QuickCalcs (GraphPad Software, San Diego). The results are presented as mean values accompanied by standard deviation (± SD). The assessment of asymmetry was performed to evaluate the normality of the various parameters. An unpaired t-test was employed to compare anthropometric and anamnestic data, along with the Musculoskeletal Tumor Society (MSTS) scores and Harris Hip Scores (HHS). A chi-square test was executed to examine complications between the two groups. Multiple linear regression was applied to investigate the relationship between functional outcomes and the incidence of complications within the study population. Furthermore, logistic regression was utilized to ascertain the odds ratios for various parameters associated with the incidence of complications. Statistical significance was determined at a p -value of less than 0.05.

Results

A total of 85 patients were examined, comprising 69 individuals who received modular mega endoprostheses (designated as group A) and 16 individuals who underwent the implantation of mega prostheses equipped with acetabular cups and dual mobility inserts (designated as group B). The mean age of the entire patient cohort was 63 years (± 15 years); specifically, patients who received modular mega endoprostheses had an average age of 63 years, while those undergoing total arthroplasty had an average age of 66 years. The average follow-up period extended to 40 months, with a minimum duration of 3 months and a maximum of 216 months. Among the patients within group A, the diagnoses included 11 cases of chondrosarcoma, 3 cases of osteosarcoma, 1 case of Ewing sarcoma, 1 case of Ewing-like sarcoma, 2 cases of pleomorphic sarcoma, 1 case of spindle cell sarcoma, and 1 additional case of pleomorphic sarcoma. The remaining diagnoses were secondary lesions localized in the proximal femur region, predominantly attributed to breast cancer (20 cases), clear cell renal carcinoma (7 cases), lung cancer (6 cases; including 1 squamous cell carcinoma and 5 adenocarcinomas), bladder cancer (2 cases), rectal adenocarcinoma (1 case), hematological tumors (1 case of multiple myeloma and 1 case of large B-cell lymphoma), pancreatic cancer (1 case), prostate adenocarcinoma (1 case), uterine leiomyosarcoma (1 case), and vulvar carcinoma (1 case). All patients who underwent total hip replacement with a tumor megaprosthesis presented with metastatic lesions. In this specific group, the most prevalent metastatic lesions were associated with breast carcinomas (6 cases), followed by hematological tumors (4 cases), lung adenocarcinomas (2 cases), and bladder adenocarcinomas (2 cases). In both groups, there were instances where the underlying diagnosis could not be established (characterized by the presence of osteolytic lesions of unknown origin) based on the hospital records. The average length of proximal femur resections was measured at 123 mm (± 16 mm); specifically, the mean resection for the modular mega endoprosthesis was 127 mm (± 16.5 mm), whereas for the total arthroplasties, it was recorded at 122 mm (± 6 mm) ( p -value 0.3). A total of 30 stems were cemented, with 7 (43%) in the arthroplasties and 23 (34%) in the endoprostheses ( p -value 0.5). Of the 16 acetabular cups, 9 were additionally secured with screws. A total of 26 complications were observed, comprising 13 dislocations, 10 instances of infection, 1 occurrence of deep vein thrombosis, 1 case of pulmonary embolism, 3 local recurrences, and 1 instance of intraoperative blood loss. Among these complications, 17 were associated with endoprostheses and 9 with arthroplasties. Of the 13 dislocations recorded, 4 were related to arthroplasties while 9 occurred in the endoprostheses; this translates to a rate of 13% among the modular mega endoprostheses and 25% among the total arthroplasties; however, this result did not yield a statistically significant p -value (0.2). Statistically significant differences between the endoprosthesis and arthroplasty groups were recognized in the overall complication rates as well as the infection rates. In terms of overall complications (including dislocations, infections, medical complications, etc.), the endoprosthesis group accounted for 17 complications out of 69 cases, representing 24.6%, in contrast to the arthroplasty group which exhibited 9 complications out of 16 cases, translating to 56.3%. This discrepancy was statistically significant, with a p -value of 0.03, indicating a higher complication rate in the arthroplasty group compared to the endoprosthesis group. Specifically focusing on infections, the difference between the two groups was even more pronounced. Within the endoprosthesis group, there were 4 infections out of 69 cases (6%), whereas in the arthroplasty group, there were 6 infections out of 16 cases (37%). This variance in infection rates was statistically significant, with a p -value of 0.002, elucidating a considerably higher infection risk in the arthroplasty group. Ultimately, among the complications classified as “medical,” there were 3 local recurrences, 1 case of deep vein thrombosis, and 1 case of pulmonary embolism, all occurring in association with mega endoprostheses. Additionally, significant intraoperative blood loss (> 500 ml) was recorded. The average duration of the surgical procedures was 168 min (± 48 min); specifically, total arthroplasty procedures lasted an average of 173 min (± 46 min), whereas modular mega endoprosthesis procedures lasted an average of 166 min (± 49 min), with a corresponding p -value of 0.6. Regarding clinical outcomes, at the three-month follow-up, total prostheses recorded a mean Harris Hip Score (HHS) of 61 (± 16), while the modular mega endoprostheses registered a mean HHS of 62 (± 25), with a p -value of 0.9. Similarly, the mean Musculoskeletal Tumor Society (MSTS) score for total prostheses was 14 (± 6), while the mean MSTS score for the modular mega endoprosthesis was 17 (± 9), with a p -value of 0.5. At the two-year follow-up, total prostheses recorded a mean HHS of 65 (± 14), while modular mega endoprostheses registered a mean HHS of 68 (± 20), with a p -value of 0.6. Conversely, the mean MSTS score for total prostheses was 15 (± 6), while the mean MSTS score for modular mega endoprostheses was 18 (± 9), with a p -value of 0.2 (Tables 2 and 3 ). Table 2 Baseline characteristics Total Group A Group B P -value Patients 85 69 16 Age 63 ± 15 63 ± 15 66 ± 14 0,4 Follow-up (months) 40 ± 12 43 ± 33 25 ± 10 0,2 Duration time surgery (min) 168 ± 48 166 ± 50 173 ± 46 0,6 Resection length (mm) 123 ± 16 127 ± 16 122 ± 6 0,3 MSTS 16 ± 8 (3 m) 17 ± 8 (24 m) 17 ± 9 (3 m) 18 ± 9 (24 m) 14 ± 6 (3 m) 15 ± 6 (24 m) 0,5 0,2 HHS 62 ± 23 (3 m) 67 ± 19 (24 m) 62 ± 25 (3 m) 68 ± 20 (24 m) 61 ± 16 (3 m) 65 ± 14 (24 m) 0,9 0,6 In brackets measurement unit; Data were reported as absolute value ± SD * Underline statistical significance Table 3 Complication Total Group A Group B P -value Patients 85 69 16 Overall complications 26 (30%) 17 (25%) 9 (56%) 0,03 * Dislocations 13 (15%) 9 (13%) 4 (25%) 0,2 Infections 10 (12%) 4 (6%) 6 (37%) 0,02 * Medical complications 5 (6%) 5 (7%) 0 0,5 DVT 2 1 Local recurrences 3 3 Data were reported as absolute value and percentage * Underline statistical significance

A multivariate model was conducted to compare the outcomes of total arthroplasty, resection, and cementing in relation to complications (refer to Table 4 ). Table 4 Multivariate regression of infection Descriptor Standard Error t-statitic P -value Total Arthroplasty 0.07 4.1 < 0,001 * Resection 0.002 0.8 0,4 Cement 0.06 −1.1 0,3 * Underline statistical signifcance

The analysis revealed that the predictor for total arthroplasty approached statistical significance, with a p -value of 0.07. This finding suggests a potential association between total arthroplasty and the incidence of complications. Although this p -value does not reach the conventional threshold of 0.05, it nonetheless warrants further investigation. In contrast, the variables for resection and cementation did not demonstrate statistically significant results, with p -values of 0.9 and 0.4, respectively.

Logistic regression was employed to investigate beyond simple linear associations, incorporating a probabilistic framework through odds ratios. This analysis further supported the premise that total arthroplasty may enhance the likelihood of complications, as evidenced by an odds ratio of 3.64. However, the p -value remains above the significance threshold at 0.08, and the broad confidence interval indicates persisting uncertainty, as observed in the multivariate analysis. Furthermore, an additional multivariate regression was performed using the same independent variables, with infections as the dependent variable. This analysis uncovered a statistically significant association between total arthroplasty and infections, as indicated by a highly significant p -value of less than 0.001. This implies that total arthroplasty increases the likelihood of infections. Conversely, resection did not exhibit a significant association with infections, as reflected by a p -value of 0.4. Similarly, the cement variable did not demonstrate a significant effect on the occurrence of infections, with a p -value of 0.3 (refer to Table 4 ).

In the present analysis, logistic regression has indicated that total arthroplasty is significantly correlated with an elevated risk of infections. The computed odds ratio for total arthroplasty is 45.3, accompanied by a p -value of 0.008, which suggests a robust and statistically significant relationship. Conversely, resection did not exhibit a significant correlation with infections, as demonstrated by a p -value of 0.5, indicating no meaningful impact on the risk of infections. Similarly, the variable concerning cement also failed to reveal a significant effect on the likelihood of infections, presenting an odds ratio of 0.20 and a p -value of 0.3, thus, suggesting no statistically significant association (Table 5 ). Table 5 Logistic regression of infection Descriptor Odds Ratio 95% Confidence interval P -value Total Arthroplasty 45,3 2,7–757,8 0,008 * Resection 1,05 0,9–1,1 0,5 Cement 0,2 0,01–3,8 0,3 * Underline statistical significance

The comprehensive analysis conducted assessed the relationship among three variables and dislocations. The findings revealed that Total Arthroplasty possesses a statistically significant correlation with dislocations, as evidenced by a p -value of 0.04. This indicates that total arthroplasty is a pertinent factor that may elevate the risk of dislocations. Conversely, Resection did not exhibit a significant correlation with dislocations, as demonstrated by a p -value of 0.7. Furthermore, the cement variable approached significance, with a p -value of 0.08, suggesting a potential influence on dislocations; however, this result does not achieve the standard threshold for statistical significance (Table 6 ). Table 6 Multivariate regression of dislocations Descriptor Standard Error t-statistic P -value Total Arthroplasty 0.1 2.0 0,04 * Resection 0.003 0.3 0,7 Cement 0.01 1.7 0,08 * Underline statistical significance

In the examination of dislocations, a logistic regression analysis was performed to assess the odds ratio. The findings reveal that total arthroplasty is significantly associated with dislocations, as substantiated by an odds ratio of 6.45 and a p -value of 0.05. This implies that total arthroplasty constitutes a substantial risk factor for dislocations. Conversely, resection does not appear to exert a significant effect on the risk of dislocations, presenting an odds ratio of 1.01 and a p -value of 0.6, indicating an insignificant impact on the likelihood of dislocations. Furthermore, the variable pertaining to cement approaches statistical significance, exhibiting an odds ratio of 4.96 and a p -value of 0.1. This indicates a possible influence on dislocations, albeit not achieving statistical significance. For additional information, please refer to Table 7 . Table 7 Logistic regression of dislocations Descriptor Odds Ratio 95% Confidence interval P -value Total Arthroplasty 6,4 0,94–44,13 0,05 * Resection 1,01 0,9–1,0 0,6 Cement 4,9 0,7–35,3 0,1 * Underline statistical significance

Discussion

Custom-made prostheses have been employed since the 1990 s to effectively reconstruct extensive bone defects and for the implementation of tumor prostheses. This process necessitates close collaboration among the surgeon, technician, and medical engineer, as well as a considerable investment of time and resources dedicated to preoperative planning. In essence, the successful development of these prostheses stems from meticulous teamwork and comprehensive preparation prior to surgery [ 22 ]. Over the years, the demand for mega prostheses has increased significantly [ 23 ]. Beyond their application in treating oncological conditions, they have also demonstrated safety and effectiveness in select cases of revision arthroplasty and complex trauma, underscoring their broader clinical value [ 24 – 26 ].

However, the various applications of mega prostheses can lead to confusion. While the development of more advanced implants, including dual mobility constructs, larger femoral heads, elevated acetabular liners, and constrained acetabular liners, may contribute to reducing instability and enhancing hip function- particularly in cases of periprosthetic fractures requiring revision with mega prostheses- our data indicate that this is not necessarily the case for primary or metastatic oncological lesions [ 27 , 28 ]. Implant failure refers to any situation necessitating a revision.

Initially, Wirganowicz et al. [ 5 ] classified complications associated with megaprostheses into mechanical and non-mechanical categories. Subsequently, Henderson et al. [ 6 ] expanded and refined this classification, identifying five distinct categories of megaprosthetic failure: soft-tissue failure (Type I), aseptic loosening (Type II), structural failure (Type III), periprosthetic infection (Type IV), and tumor progression associated with prosthetic contamination (Type V). Among these complications, the literature distinctly underscores that periprosthetic infection constitutes the most prevalent complication, notwithstanding the endeavors to enhance the materials employed in implants [ 23 , 29 ]. In our case series, we considered all these factors as complications, alongside medical issues such as deep vein thrombosis (DVT), pulmonary embolism (PE), and tumor recurrence. The overall complication rate was 30%, which is consistent with the literature, where rates vary from 25 to 92%, and approximately 24–27% in certain reports [ 22 , 30 – 32 ]. If we exclude medical complications such as DVT and PE, our complication rate would correspond to the 25% observed in other studies.

When distinguishing between endoprostheses and arthroplasties, our bivariate analysis revealed a statistically significant overall complication rate of 56. 3% for arthroplasties. However, this finding lacked corroboration from logistic regression analysis, which did not yield a statistically significant odds ratio, although it approached significance. Future research should investigate a larger cohort of total prostheses to gain a deeper understanding of this phenomenon.

The overall infection rate observed in our series was 12%, consistent with the average rates reported in the literature, which typically range from 10 to 12% [ 23 , 33 ]. Notably, the infection rate for modular endoprostheses in our study was lower, at approximately 6%. Conversely, the infection rate for total arthroplasties was significantly elevated, at 37%. Logistic regression analysis indicated that total arthroplasties presented a 45- fold increased risk of infection when compared to modular megaprostheses.

Dislocation represents a substantial complication following proximal femoral replacement (PFR), particularly within the context of orthopedic oncology. According to various studies, dislocation rates in PFRs can vary markedly based on factors such as the design of the prosthesis, the surgical technique employed, and the condition of the soft tissues [ 34 , 35 ]. The literature reports dislocation rates ranging from 5 to 8% up to 16% in PFR cases [ 33 , 36 , 37 ]. One of the major risk factors for dislocation is the loss of stabilizing soft tissues consequent to the extensive resection necessitated in tumor surgeries. The excision of vital muscles and ligaments surrounding the proximal femur compromises hip stability, resulting in a heightened likelihood of dislocation compared to primary hip arthroplasty [ 38 , 39 ]. In our case series, dislocation accounted for 15% of the total population; however, it occurred in 13% of endoprostheses while rising significantly to 25% in arthroplasties. Arthroplasties exhibited a sixfold increased likelihood of dislocation relative to endoprostheses, which may be ascribed to the greater containment afforded by the native acetabulum as opposed to the prosthetic counterpart, in conjunction with the extensive resections and soft tissue detachments that are characteristic of oncological surgeries [ 40 ].

The literature encompasses various studies that compare THA and HA, particularly highlighting a recent investigation conducted by Pala et al. This study analyzes the differences in outcomes between HA and THA utilizing a bi-mobile acetabular implant [ 41 ]. A limited number of studies have addressed the comparative results of THA and HA in the context of Proximal Femoral Epiphyseal (PFE) fractures [ 42 , 43 ]. Most of these studies suggest that HA demonstrates greater stability than THA, yielding favorable functional results; however, a significant proportion of patients may necessitate a revision from HA to THA due to the occurrence of painful cotyloiditis [ 44 ]. A reduced risk of acetabular failure (AF) has been noted in younger patients, particularly those aged 35 to 60, which could be attributable to superior bone quality. In contrast, older patients may retain the acetabulum due to their reduced levels of physical activity. Furthermore, middle-aged individuals may present with mild pre-existing hip arthritis prior to undergoing tumor surgery, a condition that has the potential to progress or exacerbate the degenerative process following HA [ 45 ].

Consequently, it is imperative to assess preoperative X- rays to identify potential indicators of arthritis in patients. Although cementation has been demonstrated to significantly increase the risk of infections, our study did not identify a statistically significant correlation. Nevertheless, a noteworthy observation is the trend between cemented prostheses and dislocations, which, despite not reaching statistical significance ( p - value = 0. 08), warrants attention. Previous research has reported a substantial incidence of soft tissue loosening associated with cemented prostheses [ 46 ]. This phenomenon may be attributable to design variations between the two categories of prostheses and the exclusive use of the Trevira tube at one oncology center.

Our study is subject to several limitations. Firstly, its retrospective design imposes inherent constraints. Additionally, the sample is heterogeneous, encompassing patients with both primary bone tumors and metastatic lesions. It also includes individuals across a broad age spectrum, from young adults to the elderly, each with distinct functional requirements. Prognostic factors such as the quantity and localization of metastases, the primary tumor type, the presence of pathological or impending fractures, and the patient’ s age can all significantly affect outcomes. Furthermore, surgical complications are often challenging to delineate and may frequently remain unreported. Another limitation arises from the employment of various prosthetic systems for limb reconstruction. For instance, the MUTARS Implantcast system utilizes Trevira tubes for tendon and muscle attachment, whereas the LINK Megasystem C depends on pre- existing holes in the prosthesis for tendon and muscle fixation. This variability in surgical methodologies may introduce additional variables that could impact the results [ 47 ]. All surgical interventions were performed by two surgeons renowned for their extensive experience in limb salvage surgery. It is crucial to acknowledge that discrepancies in the experience levels of surgeons may significantly influence outcomes, particularly in the context of complex oncological procedures contexts.

Ultimately, the primary limitation of the study is the relatively modest number of arthroplasties analyzed in relation to the total number of endoprostheses. This situation may indicate a potential avenue for future research, given that current literature on this subject is notably sparse.

Conclusions

This study underscores the complexities and challenges associated with the utilization of HA and resection arthroplasty in patients experiencing primary bone tumors and metastatic lesions. Although modular endoprostheses present a dependable option for limb salvage in oncology patients, our findings indicate notable disparities in complication rates between endoprostheses and arthroplasties. Specifically, arthroplasties are associated with elevated rates of complications, particularly infections and dislocations.

Despite the favorable outcomes linked to modular endoprostheses, the retrospective nature of the study and the heterogeneous sample impose limitations on the generalizability of the findings. Nonetheless, this observation implies a potential avenue for future research, as there currently exists a paucity of literature on this subject.

Future investigations should concentrate on larger, more homogeneous samples and explore the long-term outcomes of various prosthetic designs. Furthermore, additional inquiry into surgical techniques and postoperative rehabilitation protocols could assist in minimizing complications, ultimately enhancing patient outcomes in both primary and metastatic oncological reconstructions. Addressing these gaps in the literature could furnish clinicians with more substantial evidence to facilitate the selection of appropriate prosthetic systems for limb reconstruction.

Publisher’s Note

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Informed consent statement

Written informed consent to publish this paper was not applicable. The informed consent was waived due to the anonymized retrospective design of the study.

Authors’ 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. All authors have read and agreed to the published version of the manuscript.

Funding

This research received no external funding. None of the authors received any funds or has any financial interests to disclose. Institutional Review Board Statement: The research protocol was approved by the Institutional Review Board of Fondazione Policlinico Universitario “A Gemelli” IRCCS—Rome.

Data availability

Data available upon request.

Declarations

Competing interests

The authors declare no competing interests.

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