3-D finite element model of the impaction of a press-fitted femoral stem under various biomechanical environments.

BACKGROUND: Uncemented femoral stem insertion into the bone is achieved by applying successive impacts on an inserter tool called "ancillary". Impact analysis has shown to be a promising technique to monitor the implant insertion and to improve its primary stability. METHOD: This study aims to provide a better understanding of the dynamic phenomena occurring between the hammer, the ancillary, the implant and the bone during femoral stem insertion, to validate the use of impact analyses for implant insertion monitoring. A dynamic 3-D finite element model of the femoral stem insertion via an impaction protocol is proposed. The influence of the trabecular bone Young's modulus (Et), the interference fit (IF), the friction coefficient at the bone-implant interface (µ) and the impact velocity (v0) on the implant insertion and on the impact force signal is evaluated. RESULTS: For all configurations, a decrease of the time difference between the two first peaks of the impact force signal is observed throughout the femoral stem insertion, up to a threshold value of 0.23 ms. The number of impacts required to reach this value depends on Et, v0 and IF and varies between 3 and 8 for the set of parameters considered herein. The bone-implant contact ratio reached after ten impacts varies between 60% and 98%, increases as a function of v0 and decreases as a function of IF, µ and Et. CONCLUSION: This study confirms the potential of an impact analyses-based method to monitor implant insertion and to retrieve bone-implant contact properties.

Characterization of the concentration of agar-based soft tissue mimicking phantoms by impact analysis.

In various medical fields, a change of soft tissue stiffness is associated with its physio-pathological evolution. While elastography is extensively employed to assess soft tissue stiffness in vivo, its application requires a complex and expensive technology. The aim of this study is to determine whether an easy-to-use method based on impact analysis can be employed to determine the concentration of agar-based soft tissue mimicking phantoms. Impact analysis was performed on soft tissue mimicking phantoms made of agar gel with a mass concentration ranging from 1% to 5%. An indicator Δt is derived from the temporal variation of the impact force signal between the hammer and a small beam in contact with the sample. The results show a non-linear decrease of Δt as a function of the agar concentration (and thus of the sample stiffness). The value of Δt provides an estimation of the agar concentration with an error of 0.11%. This sensitivity of the impact analysis based method to the agar concentration is of the same order of magnitude than results obtained with elastography techniques. This study opens new paths towards the development of impact analysis for a fast, easy and relatively inexpensive clinical evaluation of soft tissue elastic properties.

Detection of periprosthetic fractures around the femoral stem by resonance frequency analysis: An in vitro study.

Periprosthetic femoral bone fractures are frequent complications of Total Hip Arthroplasty (THA) and may occur during the insertion of uncemented Femoral Stems (FS), due to the nature of the press-fit fixation. Such fracture may lead to the surgical failure of the THA and require a revision surgery, which may have dramatic consequences. Therefore, an early detection of intra-operative fractures is important to avoid worsening the fracture and/or to enable a peroperative treatment. The aim of this in vitro study is to determine the sensitivity of a method based on resonance frequency analysis of the bone-stem-ancillary system for periprosthetic fractures detection. A periprosthetic fracture was artificially created close to the lesser-trochanter of 10 femoral bone mimicking phantoms. The bone-stem-ancillary resonance frequencies in the range (2-12) kHz were measured on an ancillary instrumented with piezoelectric sensors, which was fixed to the femoral stem. The measurements were repeated for different fracture lengths from 4 to 55 mm. The results show a decrease of the resonance frequencies due to the fracture occurrence and propagation. The frequency shift reached up to 170 Hz. The minimum fracture length that can be detected varies from 3.1±1.7 mm to 5.9±1.9 mm according to the mode and to the specimen. A significantly higher sensitivity (p = 0.011) was obtained for a resonance frequency around 10.6 kHz, corresponding to a mode vibrating in a plane perpendicular to the fracture. This study opens new paths toward the development of non-invasive vibration-based methods for intra-operative periprosthetic fractures detection.

Using an Instrumented Hammer to Predict the Rupture of Bone Samples Subject to an Osteotomy.

Osteotomies are common procedures in maxillofacial and orthopedic surgery. The surgeons still rely on their proprioception to control the progression of the osteotome. Our group has developed an instrumented hammer that was shown to provide information on the biomechanical properties of the tissue located around the osteotome tip. The objective of this study is to determine if this approach may be used to predict the rupture of a bone sample thanks to an instrumented hammer equipped with a force sensor. For each impact, an indicator τ is extracted from the signal corresponding to the variation of the force as a function of time. A linear by part regression analysis is applied to the curve corresponding to the variation of τ as a function of the distance d between the tip of the osteotome and the end of the sample. The experiments were conducted with plywood and bovine trabecular bone samples. The results show that τ starts increasing when the value of d is lower than 2.6 mm on average, which therefore corresponds to a typical threshold detection distance between the osteotome tip and the sample end. These findings open new paths for the development of this instrumented surgical hammer.

Ultrasonic bandgaps in viscoelastic 1D-periodic media: Mechanical modeling and experimental validation.

Multi-material additive manufacturing is receiving increasing attention in the field of acoustics, in particular towards the design of micro-architectured periodic media used to achieve programmable ultrasonic responses. To unravel the effect of the material properties and spatial arrangement of the printed constituents, there is an unmet need in developing wave propagation models for prediction and optimization purposes. In this study, we propose to investigate the transmission of longitudinal ultrasound waves through 1D-periodic biphasic media, whose constituent materials are viscoelastic. To this end, Bloch-Floquet analysis is applied in the frame of viscoelasticity, with the aim of disentangling the relative contributions of viscoelasticity and periodicity on ultrasound signatures, such as dispersion, attenuation, and bandgaps localization. The impact of the finite size nature of these structures is then assessed by using a modeling approach based on the transfer matrix formalism. Finally, the modeling outcomes, i.e., frequency-dependent phase velocity and attenuation, are confronted with experiments conducted on 3D-printed samples, which exhibit a 1D periodicity at length-scales of a few hundreds of micrometers. Altogether, the obtained results shed light on the modeling characteristics to be considered when predicting the complex acoustic behavior of periodic media in the ultrasonic regime.

Influence of the biomechanical environment on the femoral stem insertion and vibrational behavior: a 3-D finite element study.

The long-term success of cementless surgery strongly depends on the implant primary stability. The femoral stem initial fixation relies on multiple geometrical and material factors, but their influence on the biomechanical phenomena occurring during the implant insertion is still poorly understood, as they are difficult to quantify in vivo. The aim of the present study is to evaluate the relationship between the resonance frequencies of the bone-implant-ancillary system and the stability of the femoral stem under various biomechanical environments. The interference fit IF, the trabecular bone Young's modulus [Formula: see text] and the bone-implant contact friction coefficient [Formula: see text] are varied to investigate their influence on the implant insertion phenomena and on the system vibration behavior. The results exhibit for all the configurations, a nonlinear increase in the bone-implant contact throughout femoral stem insertion, until the proximal contact is reached. While the pull-out force increases with [Formula: see text], IF and [Formula: see text], the bone-implant contact ratio decreases, which shows that a compromise on the set of parameters could be found in order to achieve the largest bone-implant contact while maintaining sufficient pull-out force. The modal analysis on the range [2-7] kHz shows that the resonance frequencies of the bone-implant-ancillary system increase with the bone-implant contact ratio and the trabecular bone Young's modulus, with a sensitivity that varies over the modes. Both the pull-out forces and the vibration behavior are consistent with previous experimental studies. This study demonstrates the potential of using vibration methods to guide the surgeons for optimizing implant stability in various patients and surgical configurations.

Ultrasound characterization of the viscoelastic properties of additively manufactured photopolymer materials.

Photopolymer-based additive manufacturing has received increasing attention in the field of acoustics over the past decade, specifically towards the design of tissue-mimicking phantoms and passive components for ultrasound imaging and therapy. While these applications rely on an accurate characterization of the longitudinal bulk properties of the materials, emerging applications involving periodic micro-architectured media also require the knowledge of the transverse bulk properties to achieve the desired acoustic behavior. However, a robust knowledge of these properties is still lacking for such attenuating materials. Here, we report on the longitudinal and transverse bulk properties, i.e., frequency-dependent phase velocities and attenuations, of photopolymer materials, which were characterized in the MHz regime using a double through-transmission method in oblique incidence. Samples were fabricated using two different printing technologies (stereolithography and polyjet) to assess the impact of two important factors of the manufacturing process: curing and material mixing. Overall, the experimentally observed dispersion and attenuation could be satisfactorily modeled using a power law attenuation to identify a reduced number of intrinsic ultrasound parameters. As a result, these parameters, and especially those reflecting transverse bulk properties, were shown to be very sensitive to slight variations of the manufacturing process.

Ultrasound characterization of bioinspired functionally graded soft-to-hard composites: Experiment and modeling.

Functional grading is a distinctive feature adopted by nature to improve the transition between tissues that present a strong mismatch in mechanical properties, a relevant example being the tendon-to-bone attachment. Recent progress in multi-material additive manufacturing now allows for the design and fabrication of bioinspired functionally graded soft-to-hard composites. Nevertheless, this emerging technology depends on several design variables, including both material and mechanistic ingredients, that are likely to affect the mechanical performance of such composites. In this paper, a model-based approach is developed to describe the interaction of ultrasound waves with homogeneous and heterogeneous additively manufactured samples, which respectively display a variation either of the material ingredients (e.g., ratio of the elementary constituents) or of their spatial arrangement (e.g., functional gradients, damage). Measurements are performed using longitudinal bulk waves, which are launched and detected using a linear transducer array. First, model is calibrated by exploiting the signals measured on the homogeneous samples, which allow identifying relationships between the model parameters and the material composition. Second, the model is validated by comparing the signals measured on the heterogeneous samples with those predicted numerically. Overall, the reported results pave the way for characterizing and optimizing multi-material systems that display complex bioinspired features.

Understanding the Relationship between Fetal Alcohol Spectrum Disorder (FASD) and Criminal Justice: A Systematic Review.

Prenatal alcohol exposure is considered one of the main causes of preventable birth disorders; however, it represents the main form of developmental delay in the world. Among the so-called secondary disabilities related to fetal alcohol spectrum disorder (FASD), there is a close connection with criminal behavior. This systematic review aims to provide up-to-date information about the relationship between FASD subjects and criminal justice analyzing different aspects. In light of the results of this review, a further goal is to provide several suggestions in order to reduce the public cost impact of FASD. A systematic review of the literature was conducted according to the PRISMA guidelines, producing 20 articles that met the inclusion criteria. Based on the results published in the selected studies, fetal alcohol syndrome (FAS) is a leading cause of preventable birth disorders and developmental disabilities in newborns. Moreover, these subjects seem to be more inclined to criminal acts compared to others. In conclusion, it should be pointed out that FASD entails high public health costs, both regarding the support measures provided to the affected individual and to their family, as well as the cost and social impact of any criminal offenses committed.

Modal Analysis of the Ancillary During Femoral Stem Insertion: A Study on Bone Mimicking Phantoms.

The femoral stem primary stability achieved by the impaction of an ancillary during its insertion is an important factor of success in cementless surgery. However, surgeons still rely on their proprioception, making the process highly subjective. The use of Experimental Modal Analysis (EMA) without sensor nor probe fixation on the implant or on the bone is a promising non destructive approach to determine the femoral stem stability. The aim of this study is to investigate whether EMA performed directly on the ancillary could be used to monitor the femoral stem insertion into the bone. To do so, a cementless femoral stem was inserted into 10 bone phantoms of human femurs and EMA was carried out on the ancillary using a dedicated impact hammer for each insertion step. Two bending modes could be identified in the frequency range [400-8000] Hz for which the resonance frequency was shown to be sensitive to the insertion step and to the bone-implant interface properties. A significant correlation was obtained between the two modal frequencies and the implant insertion depth (R2 = 0.95 ± 0.04 and R2 = 0.94 ± 0.06). This study opens new paths towards the development of noninvasive vibration based evaluation methods to monitor cementless implant insertion.

Validation of an Instrumented Hammer for Rhinoplasty Osteotomies: A Cadaveric Study.

Background: Osteotomies during rhinoplasty are usually based on surgeon's proprioception to determine the number, energy, and trajectory of impacts. Objective: The first objective was to detect the occurrence of fractures. The second objective was to determine when the thicker frontal bone was encountered by the osteotome. Materials and Methods: An instrumented hammer was used to measure the impact force during lateral osteotomies on nine human anatomic specimens. A prediction algorithm was developed using machine learning techniques, to detect the occurrence of fractures, and the proximity of the osteotome to the frontal bone. Results: The algorithm was able to predict the occurrence of fractures and the proximity to the frontal bone with a prediction rate of 83%, 91%, and 93% when allowing for an error of 0, 1, and 2 impacts, respectively. The location of the osteotome in the frontal bone was predicted with an error of 7.7%. Conclusion: An osteotomy hammer measuring the impact force when performing lateral osteotomies can predict the occurrence of fractures and the proximity to the frontal bone, providing the surgeon with instant feedback.

Anatomical subject validation of an instrumented hammer using machine learning for the classification of osteotomy fracture in rhinoplasty.

Osteotomies during rhinoplasty are usually based on the surgeon's proprioception to determine the number and the strength of the impacts. The aim of this study is to determine whether a hammer instrumented with a force sensor can be used to classify fractures and to determine the location of the osteotome tip. Two lateral osteotomies were realized in nine anatomical subjects using an instrumented hammer recording the evolution of the impact force. Two indicators τ and λ were derived from the signal, and video analysis was used to determine whether the osteotome tip was located in nasal or frontal bone as well as the condition of the bone tissue around the osteotome tip. A machine-learning algorithm was used to predict the condition of bone tissue after each impact. The algorithm was able to predict the condition of the bone after the impacts with an accuracy of 83%, 91%, and 93% when considering a tolerance of 0, 1, and 2 impacts, respectively. Moreover, in nasal bone, the values of τ and λ were significantly lower (p < 10-10) and higher (p < 10-4) than in frontal bone, respectively. This study paves the way for the development of the instrumented hammer as a decision support system.

Smart drugs and neuroenhancement: what do we know?

Introduction: Smart drugs are among the most common drugs used by students. It is estimated that they are second in incidence after cannabis. Although they are usually used for diseases such as attention deficit hyperactivity disorder (ADHD) and dementia, in most cases the use of smart drugs is illegal and without a prescription. Methodological issues: A systematic review was conducted according to PRISMA guidelines. SCOPUS, Medline (using PubMed as a search engine), Embase, Web of Sciences, and Google Scholar were used as search engines from January 1, 1980 to June 1, 2021 to evaluate the association between smart drugs and neuro-enhancement. A total of 4715 articles were collected. Of these, 295 duplicates were removed. A total of 4380 articles did not meet the inclusion criteria. In conclusion, 48 articles were included in the present systematic review. Results: Most of the studies were survey studies, 1 was a prospective longitudinal study, 1 was a cross-over study, and 1 was an experimental study in an animal model (rats). The largest group of consumers was school or university students. The most frequent reasons for using smart drugs were: better concentration, neuro enhancement, stress reduction, time optimization, increased wake time, increased free time, and curiosity. There are conflicting opinions, in fact, regarding their actual functioning and benefit, it is not known whether the benefits reported by consumers are due to the drugs, the placebo effect or a combination of these. The real prevalence is underestimated: it is important that the scientific community focus on this issue with further studies on animal models to validate their efficacy.

Using an impact hammer to perform biomechanical measurements during osteotomies: Study of an animal model.

Osteotomies are common surgical procedures used for instance in rhinoplasty and usually performed using an osteotome impacted by a mallet. Visual control being difficult, osteotomies are often based on the surgeon proprioception to determine the number and energy of each impact. The aim of this study is to determine whether a hammer instrumented with a piezoelectric force sensor can be used to (i) follow the displacement of the osteotome and (ii) determine when the tip of the osteotome arrives in frontal bone, which corresponds to the end of the osteotomy pathway. Seven New Zealand White rabbit heads were collected, and two osteotomies were performed on their left and right nasal bones using the instrumented hammer to record the variation of the force as a function of time during each impact. The second peak time τ was derived from each signal while the displacement of the osteotome tip D was determined using video motion tracking. The results showed a significant correlation between τ and D (ρ2 = 0.74), allowing to estimate the displacement of the osteotome through the measurement of τ. The values of τ measured in the frontal bone were significantly lower than in the nasal bone (p<10-10), which allows to determine the transition between the nasal and frontal bones when τ becomes lower than 0.78 its initial averaged value. Although results should be validated clinically, this technology could be used by surgeons in the future as a decision support system to help assessing the osteotome environment.

Adverse Effects of Anabolic-Androgenic Steroids: A Literature Review.

Anabolic-androgenic steroids (AASs) are a large group of molecules including endogenously produced androgens, such as testosterone, as well as synthetically manufactured derivatives. AAS use is widespread due to their ability to improve muscle growth for aesthetic purposes and athletes' performance, minimizing androgenic effects. AAS use is very popular and 1-3% of US inhabitants have been estimated to be AAS users. However, AASs have side effects, involving all organs, tissues and body functions, especially long-term toxicity involving the cardiovascular system and the reproductive system, thereby, their abuse is considered a public health issue. The aim of the proposed review is to highlight the most recent evidence regarding the mechanisms of action of AASs and their unwanted effects on organs and lifestyle, as well as suggesting that AAS misuse and abuse lead to adverse effects in all body tissues and organs. Oxidative stress, apoptosis, and protein synthesis alteration are common mechanisms involved in AAS-related damage in the whole body. The cardiovascular system and the reproductive system are the most frequently involved apparatuses. Epidemiology as well as the molecular and pathological mechanisms involved in the neuropsychiatric side-effects of AAS abuse are still unclear, further research is needed in this field. In addition, diagnostically reliable tests for AAS abuse should be standardized. In this regard, to prevent the use of AASs, public health measures in all settings are crucial. These measures consist of improved knowledge among healthcare workers, proper doping screening tests, educational interventions, and updated legislation.

Nandrolone Decanoate: Use, Abuse and Side Effects.

Background and Objectives: Androgens play a significant role in the development of male reproductive organs. The clinical use of synthetic testosterone derivatives, such as nandrolone, is focused on maximizing the anabolic effects and minimizing the androgenic ones. Class II anabolic androgenic steroids (AAS), including nandrolone, are rapidly becoming a widespread group of drugs used both clinically and illicitly. The illicit use of AAS is diffused among adolescent and bodybuilders because of their anabolic proprieties and their capacity to increase tolerance to exercise. This systematic review aims to focus on side effects related to illicit AAS abuse, evaluating the scientific literature in order to underline the most frequent side effects on AAS abusers' bodies. Materials and Methods: A systematic review of the scientific literature was performed using the PubMed database and the keywords "nandrolone decanoate". The inclusion criteria for articles or abstracts were English language and the presence of the following words: "abuse" or "adverse effects". After applying the exclusion and inclusion criteria, from a total of 766 articles, only 148 were considered eligible for the study. Results: The most reported adverse effects (found in more than 5% of the studies) were endocrine effects (18 studies, 42%), such as virilization, gynecomastia, hormonal disorders, dyslipidemia, genital alterations, and infertility; cardiovascular dysfunctions (six studies, 14%) such as vascular damage, coagulation disorders, and arteriosus hypertension; skin disorders (five studies, 12%) such as pricking, acne, and skin spots; psychiatric and mood disorders (four studies, 9%) such as aggressiveness, sleep disorders and anxiety; musculoskeletal disorders (two studies, 5%), excretory disorders (two studies, 5%), and gastrointestinal disorders (two studies, 5%). Conclusions: Based on the result of our study, the most common adverse effects secondary to the abuse of nandrolone decanoate (ND) involve the endocrine, cardiovascular, skin, and psychiatric systems. These data could prove useful to healthcare professionals in both sports and clinical settings.

Sudden Cardiac Death in Anabolic-Androgenic Steroid Users: A Literature Review.

Background and objectives: Anabolic-androgenic steroids (AASs) are a group of synthetic molecules derived from testosterone and its related precursors. AASs are widely used illicitly by adolescents and athletes, especially by bodybuilders, both for aesthetic uses and as performance enhancers to increase muscle growth and lean body mass. When used illicitly they can damage health and cause disorders affecting several functions. Sudden cardiac death (SCD) is the most common medical cause of death in athletes. SCD in athletes has also been associated with the use of performance-enhancing drugs. This review aimed to focus on deaths related to AAS abuse to investigate the cardiac pathophysiological mechanism that underlies this type of death, which still needs to be fully investigated. Materials and Methods: This review was conducted using PubMed Central and Google Scholar databases, until 21 July 2020, using the following key terms: "((Sudden cardiac death) OR (Sudden death)) AND ((androgenic anabolic steroid) OR (androgenic anabolic steroids) OR (anabolic-androgenic steroids) OR (anabolic-androgenic steroid))". Thirteen articles met the inclusion and exclusion criteria, for a total of 33 reported cases. Results: Of the 33 cases, 31 (93.9%) were males while only 2 (61%) were females. Mean age was 29.79 and, among sportsmen, the most represented sports activity was bodybuilding. In all cases there was a history of AAS abuse or a physical phenotype suggesting AAS use; the total usage period was unspecified in most cases. In 24 cases the results of the toxicological analysis were reported. The most detected AASs were nandrolone, testosterone, and stanozolol. The most frequently reported macroscopic alterations were cardiomegaly and left ventricular hypertrophy, while the histological alterations were foci of fibrosis and necrosis of the myocardial tissue. Conclusions: Four principal mechanisms responsible for SCD have been proposed in AAS abusers: the atherogenic model, the thrombosis model, the model of vasospasm induced by the release of nitric oxide, and the direct myocardial injury model. Hypertrophy, fibrosis, and necrosis represent a substrate for arrhythmias, especially when combined with exercise. Indeed, AAS use has been shown to change physiological cardiac remodeling of athletes to pathophysiological cardiac hypertrophy with an increased risk of life-threatening arrhythmias.

Ex vivo estimation of cementless femoral stem stability using an instrumented hammer.

BACKGROUND: The success of cementless hip arthroplasty depends on the primary stability of the femoral stem. It remains difficult to assess the optimal number of impacts to guarantee the femoral stem stability while avoiding bone fracture. The aim of this study is to validate a method using a hammer instrumented with a force sensor to monitor the insertion of femoral stem in bovine femoral samples. METHODS: Different cementless femoral stem were impacted into five bovine femur samples, leading to 99 configurations. Three methods were used to quantify the insertion endpoint: the impact hammer, video motion tracking and the surgeon proprioception. For each configuration, the number of impacts performed by the surgeon until he felt a correct insertion was noted Nsurg. The insertion depth E was measured through video motion tracking, and the impact number Nvid corresponding to the end of the insertion was estimated. Two indicators, noted I and D, were determined from the analysis of the time variation of the force, and the impact number Nd corresponding to a threshold reached in D variation was estimated. FINDINGS: The pullout force of the femoral stem was significantly correlated with I (R2 = 0.81). The values of Nsurg, Nvid and Nd were similar for all configurations. INTERPRETATION: The results validate the use of the impact hammer to assess the primary stability of the femoral stem and the moment when the surgeon should stop the impaction procedure for an optimal insertion, which could lead to the development of a decision support system.

Using an Impact Hammer to Estimate Elastic Modulus and Thickness of a Sample During an Osteotomy.

Performing an osteotomy with a surgical mallet and an osteotome is a delicate intervention mostly based on the surgeon proprioception. It remains difficult to assess the properties of bone tissue being osteotomized. Mispositioning of the osteotome or too strong impacts may lead to bone fractures which may have dramatic consequences. The objective of this study is to determine whether an instrumented hammer may be used to retrieve information on the material properties around the osteotome tip. A hammer equipped with a piezo-electric force sensor was used to impact 100 samples of different composite materials and thicknesses. A model-based inversion technique was developed based on the analysis of two indicators derived from the analysis of the variation of the force as a function of time in order to (i) classify the samples depending on their material types, (ii) determine the materials stiffness, and (iii) estimate the samples thicknesses. The model resulting from the classification using support vector machines (SVM) learning techniques can efficiently predict the material of a new sample, with an estimated 89% prediction performance. A good agreement between the forward analytical model and the experimental data was obtained, leading to an average error lower than 10% in the samples thickness estimation. Based on these results, navigation and decision-support tools could be developed and allows surgeons to adapt their surgical strategy in a patient-specific manner.

A cadaveric validation of a method based on impact analysis to monitor the femoral stem insertion.

The success of cementless hip arthroplasty depends on the primary stability of the femoral stem (FS). It remains difficult to assess the optimal impaction energy to guarantee the FS stability while avoiding bone fracture. The aim of this study is to compare the results of a method based on the use of an instrumented hammer to determine the insertion endpoint of cementless FS in a cadaveric model with two other methods using i) the surgeon proprioception and ii) video motion tracking. Different FS were impacted in nine human cadaveric femurs. For each configuration, the number of impacts realized when the surgeon felt that the FS was correctly inserted was noted Nsurg. For each impact, the insertion depth E was measured and an indicator D was determined based on the time-variation of the force. The impact number Nvid (respectively Nd), corresponding to the end of the migration phase, was estimated analyzing the evolution of E (respectively D). The respective difference between Nsurg, Nvid and Nd was similar and lower than 3 for more than 85% of the configurations. The results allow a validation of the use of an impact hammer to assess the moment when the surgeon should stop the impaction, paving the way towards the development of a decision support system to assist the surgeon.