Concentration of Sonication Fluid through Centrifugation Is Superior to Membrane Filtration for Microbial Diagnosis of Orthopedic Implant-Associated Infection.

Microbial identification of orthopedic implant-associated infections using sonication fluid (SF) submitted to a concentration step by membrane filtration (SMF) was compared with the standard centrifugation (SC) method. Among 33 retrieved infected implants, sonication identified microorganisms in 26 (78.8%). The sensitivity of SC was higher than that of SMF (78.8% versus 30.3%; P < 0.001).

Prevalence and risk factors for intra-operative periprosthetic fractures in one thousand eight hundred and seventy two patients undergoing total hip arthroplasty: a cross-sectional study.

PURPOSE: The purpose of this study was to identify the frequency and type of intra-operative periprosthetic fractures and to describe risk factors in a single tertiary, public hospital, so that these events could be prevented, even among less experienced surgeons. METHODS: This is a cross-sectional study, based on medical records and imaging exams from the archives of a public, tertiary hospital, from April 1998 to October 2013. All consecutive patients submitted to total hip arthroplasty (THA) in the study period were evaluated, excluding unipolar or bipolar arthroplasty, surgery for the osteosynthesis of periprosthetic fractures, surgical procedure to clean infection site without component substitution and not arthroplastic surgery. Data were analyzed with chi-squared test and multivariate Cox regression. RESULTS: In the study period, 1,872 THA (1,728 patients) were performed and analyzed, with 144 bilateral cases. In 173 cases, patients had undergone surgical procedures other than THA previously, and in only 260 the surgery consisted of revision THA. There were only two cases of resection THA. Among all patients 101 intra-operative periprosthetic fractures occurred. The univariate analysis revealed a significantly higher risk of intra-operative fractures in female patients, aged more than 65 years, with indication of primary THA and the presence of a previous hip surgery. It indicated also that revision surgeries were associated with a 2.8-fold higher risk of intra-operative fracture, 2.18-fold risk in a previously operated hip and 3.9-fold in cases of resection THA or revision surgery in two stages. CONCLUSIONS: Intraoperative periprosthetic fracture is a rare event, and it is associated with revision type surgery and THA in a previously operated hip.

Medial hip arthroscopy portals: an anatomic study.

PURPOSE: The main objective of this study was to investigate medial hip portals and evaluate their relation with anatomic structures in a cadaveric model. METHODS: Placement of 3 medial arthroscopic portals was simulated in 10 fresh human paired cadaveric hip specimens by placing Steinmann pins into the joint under fluoroscopic control. Two portals were made at the groin, 1 anterior and 1 posterior to the adductor longus muscle, and the third portal was placed posterior to the adductor longus muscle, 5 cm distal to the groin. The specimens were then dissected, and the relation of the portals to the following structures was recorded: pectineus, adductor longus, gracilis, adductor brevis, adductor magnus, iliopsoas tendon, obturator nerve, femoral nerve, femoral artery, femoral vein, and profunda femoris artery. RESULTS: Regarding the anteromedial portal, the closest neurovascular structure was the profunda femoris artery, which was 10.4 ± 2.7 mm (range, 6 to 14 mm) distal to the portal. Regarding the posteromedial portal, the nearest neurovascular structure was the obturator nerve, which was 6.0 ± 3.6 mm (range, 2 to 13 mm) posterior to the portal. Regarding the distal posteromedial portal, the nearest neurovascular structures were the obturator nerve, which was 4.6 ± 3.0 mm (range, 1 to 9 mm) distal to the portal, and the profunda femoris artery, which was 10.5 ± 3.9 mm (range, 6 to 17 mm) distal to the portal. CONCLUSIONS: The use of the medial portals did not cause any damage to the neurovascular structures evaluated. Despite this, the portals are in close relation to the obturator nerve and profunda femoris, and care should be taken. CLINICAL RELEVANCE: This study investigated 3 medial hip portals in a cadaveric model and also defined safety parameters for this approach. Medial hip portals may be useful to directly approach medial hip pathologies.

Surgical technique: Endoscopic gluteus maximus tendon release for external snapping hip syndrome.

BACKGROUND: While many authors have recommended surgery for patients with persistent symptoms of external snapping hip, it is unclear which one best relieves symptoms. Concerns with iliotibial band (ITB)-modifying techniques include altering the shape of the lateral thigh and overload of the contralateral abduction mechanism. We describe a new endoscopic technique that decreases the tension of the ITB complex by releasing the femoral insertion of the gluteus maximus tendon (GMT). DESCRIPTION OF TECHNIQUE: Via an endoscopic approach, we tenotomize the GMT near its insertion at the linea aspera through two trochanteric portals, developing a space beneath the ITB. METHODS: We reviewed eight patients (nine hips) with external snapping hip nonresponsive to nonoperative treatment treated by endoscopic GMT release. There were seven women (one bilateral) and one man, with a mean ± SD age of 35 ± 13.1 years (range, 18-55 years). Mean symptom duration was 36 ± 20.3 months (range, 16-84 months). Minimum followup was 22 months (mean, 32 ± 9.3 months; range, 22-45 months). RESULTS: Snapping and pain resolved in seven patients after the initial procedure. We performed one revision procedure with complete relief of symptoms. All eight patients returned to their previous level of activity. Average modified Harris hip score was 61 points (range, 45-70 points) preoperatively and 78 points (range, 62-93 points) at latest followup. We observed no neurovascular complications. CONCLUSIONS: Our small series suggests endoscopic release of the GMT resolves pain and snapping symptoms in most patients.

Accuracy of Hip Pericapsular Nerve Block (PENG) without Ultrasound Aid in Patients with Hip Pain.

Objective To describe and evaluate the accuracy of the pericapsular nerve group (PENG) block technique with no ultrasound guidance. Method Series of 40 infiltrations in patients with hip pain undergoing outpatient follow-up in the hip surgery group or admitted to the emergency room from a hospital in São Paulo, SP, Brazil. The hip PENG technique was guided by palpable anatomical pelvic structures, with no ultrasound orientation for needle positioning, using the equipment only to check the correct location after an unguided puncture. Results In the 40 hips infiltrated from 35 patients with a mean age of 59.2 years, the success rate was 85%. Among the mispositioned cases, 71.4% occurred in the first 13 applications and 28.6% in the subsequent 27 applications. In all patients, the neurovascular bundle was in the medial third of the pen-made demarcation. Even in cases with a failed needle location, the distance from the neurovascular bundle was safe. A single adverse effect occurred, with spontaneous improvement of the femoral nerve apraxia within two days. Conclusion Unguided PENG block is a viable technique for a physician knowledgeable about its application in services with no ultrasound availability.

Block of the Pericapsular Nerve Group of the Hip with and without Ultrasound Guidance: Comparative Cadaveric Study.

Objective To evaluate the technical reproducibility of a block of the pericapsular nerve group (PENG) of the hip aided or not by ultrasound in cadavers. Materials and Methods The present is a randomized, descriptive, and comparative anatomical study on 40 hips from 2 cadaver groups. We compared the PENG block technique with the method with no ultrasound guidance. After injecting a methylene blue dye, we verified the dispersion and topographical staining of the anterior hip capsule through dissection. In addition, we evaluated the injection orifice in both techniques. Results In the comparative analysis of the techniques, there were no puncture failures, damage to noble structures in the orifice path, or differences in the results. Only 1 hip from each group (5%) presented inadequate dye dispersion within the anterior capsule, and in 95% of the cases submitted to either technique, there was adequate dye dispersion at the target region. Conclusion Hip PENG block with no ultrasound guidance is feasible, safe, effective, and highly reliable compared to its conventional counterpart. The present is a pioneer study that can help patients with hip pain from various causes in need of relief.

Correlation between the range of rotation of the hip and the radiographic signs of cam and pincer morphology in femoroacetabular impingement syndrome.

OBJECTIVE: To determine whether hip rotation correlates with the radiographic signs of cam or pincer deformity after hip arthroscopy in patients with femoroacetabular impingement syndrome. MATERIALS AND METHODS: This was a single-center retrospective study of data collected between 2014 and 2017. The study sample included 65 patients between 18 and 55 years of age who underwent hip arthroscopy for the treatment of unilateral femoroacetabular impingement. The following data were collected for the periods prior to and six months after surgery range of medial and lateral rotation of the hip; measures on anteroposterior X-rays of the pelvis obtained in the standing position and on ateral X-rays in the Ducroquet profile view; and score on the 33-item International Hip Outcome Tool. RESULTS: Mean preoperative and postoperative values were as follows: 19.26 ± 10.39° and 30.95 ± 3.52°, respectively, for medial rotation of the hip (p < 0.001); 73.85 ± 6.62° and 68.12 ± 5.04°, respectively, for the anteroposterior alpha angle (p < 0.001); 56.97 ± 6.09° and 50.61 ± 5.39°, respectively, for the lateral alpha angle (p < 0.001); and 0.17 ± 0.11 and 0.07 ± 0.08, respectively, for the acetabular retroversion index (p < 0.001). The crossover sign was identified in 75.4% of the patients before surgery and in 44.6% after (p < 0.001). Although there was an increase in the range of hip rotation and an improvement in radiographic parameters after arthroscopy, we detected no direct correlation between the two. CONCLUSION: Hip arthroscopy can improve medial rotation of the hip, as well as reducing cam and pincer deformities, in patients with femoroacetabular impingement syndrome. However, those findings do not appear to be directly correlated.

OBJETIVO: Correlacionar rotação medial do quadril com sinais radiográficos came e pincer de pacientes com síndrome do impacto femoroacetabular submetidos a artroscopia. MATERIAIS E MÉTODOS: Estudo retrospectivo com prontuários consecutivos de 2014 a 2017 em único centro. O estudo incluiu 65 pacientes com impacto femoroacetabular unilateral, de ambos os sexos e idade entre 18 e 55 anos, com indicação de artroscopia do quadril. Os dados colhidos no pré-operatório e pós-operatório de seis meses foram: amplitude de rotação medial e rotação lateral do quadril, mensurações de radiografia anteroposterior da pelve em ortostatismo e perfil de Ducroquet, escala visual analógica de dor e questionário de qualidade de vida International Hip Outcome Tool 33. RESULTADOS: A amplitude pré-operatória de rotação medial do quadril foi, em média, 19,26 ± 10,39°, e pós-operatória, 30,95 ± 3,52° (p < 0,001). Para ângulo alfa anteroposterior, o valor médio pré-operatório foi 73,85 ± 6,62°, e após cirurgia, 68,12 ± 5 , 0 4 ° ( p < 0,001). Já o ângulo alfa perfil pré - operatório e pós- operatório foi, respectivamente, 56,97 ± 6,09° e 50,61 ± 5,39° (p < 0,001). O sinal do cruzamento foi presente em 75,40% (pré-cirurgia) e após cirurgia em 44,60% (p < 0,001). O índice de retroversão acetabular pré-operatório, em média, foi 0,17 ± 0,11, e pós-operatório, 0,07 ± 0,08 (p < 0,001). Embora tenham sido observados aumento na amplitude de rotação do quadril e melhora dos parâmetros radiográficos após artroscopia, não houve correlação direta entre as variáveis. CONCLUSÃO: A artroscopia do quadril pode promover normalização da amplitude de rotação medial do quadril e redução dos sinais radiográficos came e pincer nos pacientes com síndrome do impacto femoroacetabular, porém, estes achados não possuem correlação direta.

Correlation between Intensity of Pain and Disability Due to Intra-articular Lesions in Patients with Femoroacetabular Impingement Syndrome.

Objective To correlate radiographic alterations and lesions in intra-articular structures of the acetabulum with the intensity of pain and disability of patients diagnosed with femoroacetabular impingement syndrome. Methods A retrospective analysis of the preoperative data of 182 patients (190 hips) was performed. Clinical variables such as age, gender, the practice of physical activity, and radiographic variables, such as the Wiberg and alpha angles, were evaluated. Through an intraoperative video, the extent of the chondral and labial lesions was evaluated considering the clock-face method, the degree of joint involvement by the Outerbridge classification, and the presence of wave lesions. The variables were analyzed by linear regression, with the intensity of the pain assessed by the Visual Analog Scale (VAS), and functional disability measured by the Modified Harris Hip Score (mHHS). Results The mean age of the patients was of 38.5 ± 9.6 years, the mean intensity of the pain was of 7.8 ± 1.6, and the mean mHHS score was of 56.3 ± 12.7. In total, 61% of the sample were classified as Outerbridge III or IV, and 12.6% had wave lesions. There was a correlation between the male gender (r = 0.497) and lower intensity of the pain, and a correlation of age (r = -0.27), the male gender (r = 8.419) and physical activity with higher functional scores on the mHHS (r = 4.729). Conclusion There was no correlation of the radiographic and arthroscopic parameters of the present study and the intensity of pain and the disability of the patients. The male gender is related to lower intensity of pain, and higher functional ability is related to the male gender, lower age, and the practice of physical activity. Level of Evidence IV.

Is There Any Difference Between a Spherical Marker and a Simple Coin for Hip Replacement Digital Planning?

Objective To evaluate the accuracy and differences between 2 types of metallic markers, sphere, and coin, for radiographic calibration in the preoperative planning of hip arthroplasty. Methods Four spherical metallic markers and four coins, both 25 mm in diameter, were placed on the greater trochanter, pubic symphysis, between the thighs, and on the table of the exam, for radiographic examination of the hip in 33 patients with hip prosthesis. The prosthesis head was used for calibration and two examiners measured the markers' image diameters, and the results were analyzed statistically. Results In the greater trochanter, the sphere and the coin were not visualized in 19 radiographs (57.6%). Between the thighs, the coin marker was not visualized in 13 radiographs (39.4%). In the greater trochanter, the 25-mm accuracy of the coin and the sphere was, respectively, between 57.1 and 63.3% and between 64.3 and 92.9%. The coin between the thighs reached 25-mm accuracy in between 50 and 60% of cases. Over the exam table, the coin and sphere markers reached, respectively, the mean diameters of 22.91 mm and 23 mm, the lowest coefficient of variation, the lowest confidence interval, and the easiest positioning. There was statistical difference between the evaluations of the markers (coin vs. sphere) in all positions ( p < 0.032), except for the exam table position ( p = 0.083). Conclusions The coin between the thighs is the best marker for radiographic calibration in the preoperative planning of hip arthroplasty, and we suggest the use of another coin on the exam table for comparison, considering the 8% reduction in relation to its real size.

Patient Education in Orthopedics: the Role of Information Design and User Experience.

PURPOSE OF REVIEW: This narrative review will focus on concepts and methods of Information Design and User Experience for patient education in orthopedics, with osteoarthritis as an application example. RECENT FINDINGS: Information design can make complex health information clear according to the needs of the patients. Digital health presents new opportunities to design scalable educational interventions and may be improved with User Experience Design. Human-centered design methods such as user research, co-design, and prototype testing are being applied in orthopedics to achieve patient-centered care. Current international guidelines on osteoarthritis put patient education as one of the key care strategies. Educational interventions target preoperative education and osteoarthritis self-management, but current models could be enhanced. Patient education and health literacy are fundamental to face the burden of musculoskeletal pain. The collaboration between design and health is essential to deal with the demand for education, behavioral, and social change.

Intrapelvic entrapment of sacral nerve roots by abnormal bundles of the piriformis muscle: description of an extra-spinal cause of sciatica and pudendal neuralgia.

Piriformis syndrome is a well-known extra-spinal cause of sciatica characterized by the entrapment of the sciatic nerve by variant bundles of the piriformis muscles in the deep gluteal space. In this case series, we describe the entrapment of intrapelvic portions of the sacral nerve roots by a variant bundle of the piriformis muscle originating medially to the sacral foramina, the surgical technique for the laparoscopic treatment of this condition, and the outcomes of the first eight cases treated with this technique. Five female and three male patients presenting with sciatica, pudendal pain and lower urinary tract symptoms underwent a laparoscopic exploration of the intrapelvic portion of the sacral nerve roots and transection of the abnormal piriformis bundle. Surgical technique is demonstrated in the Supplementary Video. Clinical success was achieved in seven of the eight patients, with a reduction of pain numeric rating scale from 8.5 (±1.2; 7-10) pre-operatively to 2.1 (±2.6; 0-7), 1-year following surgery. In conclusion, entrapment of intrapelvic portions of the sacral nerve roots by variant bundles of the piriformis originating medially to the sacral foramina are an extraspinal cause of sciatica, which can be treated though a laparoscopic approach.

Greater trochanteric pain syndrome in women: Analysis of magnetic resonance, sagittal alignment, muscular strength and endurance of the hip and trunk.

INTRODUCTION: There are many studies on the Greater Trochanteric Pain Syndrome (GTPS), however its relationship with radiographic and biomechanics parameters is not established. OBJECTIVE: To compare the magnetic resonance images (MRI) of the hip, radiographic parameters of sagittal alignment (pelvic incidence, sacral slope and lumbar lordosis), muscular strength and endurance in women with and without GTPS. METHODS: Forty women, age over 45, IMC <30 Kg/m2 and sedentary, were recruited and distributed in two groups: GTPS group (GTPSG, n = 20) and Control group (CG, n = 20). All participants underwent MRI scans and X-ray for sagittal alignment analysis in the hip and performed tests for muscular strength and endurance of the hip and trunk. RESULTS: No differences were found between the GTPSG and CG for the frequency of tendinopathy (P = .30), peritendinitis (P = .10), bursitis (P = .68) and enthesitis (P = .15), however the gluteus medius tendon tear was more prevalent in GTPSG (P = .05). There were no differences in radiographic parameters for pelvic incidence (P > .05), sacral slope (P > .05) and lumbar lordosis (P > .05). The GTPSG showed lower strength of all hip muscle groups (abductors, adductors, flexors, extensors and rotators; P < .01 for all), as well as lower endurance in the Supine Bridge test and Prone bridge test (P < .01). CONCLUSION: The results of the MRI and radiographic parameters did not differentiate women with and without GTPS. However, the evaluation of muscle strength and endurance can establish the difference between groups.

Trapezoidal bony correction of the femoral neck in the treatment of severe acute-on-chronic slipped capital femoral epiphysis.

PURPOSE: To present the first technical description of a modified surgical technique for trapezoidal bony correction of the femoral neck in the treatment of slipped capital femoral epiphysis (SCFE), performed entirely by arthroscopy. METHODS: From December 2005 to January 2008, 5 patients with severe SCFE underwent trapezoidal femoral neck bone correction through arthroscopy. Their mean age at the time of surgery was 13.2 years. The time for postoperative follow-up ranged from a minimum of 12 months to a maximum of 39 months (mean, 26 months). The study analyzed data regarding the type of slip, degree of correction obtained, clinical and functional outcomes, and complications. RESULTS: Analysis with the modified Harris Hip Score criteria showed a mean of 17.2 points preoperatively and 86.6 points at the last assessment. The mean epiphyseal deviation ranged from 82° at the initial presentation to 14° postoperatively. There were no intraoperative complications, and there was 1 case of avascular necrosis. CONCLUSIONS: Arthroscopic treatment of SCFE resulted in correction of the angles of epiphyseal slip (from a mean epiphyseal-diaphyseal angle of 82° before surgery to 14° after surgery), with no immediate complications and 1 case of a late complication (avascular necrosis) in this 5-patient series. Clinical improvement was shown by a mean 69.4-point increase in the modified Harris Hip Score. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Do complications in hip arthroscopy change with experience?

PURPOSE: The aim of this study was to evaluate the type and incidence of complications during the development of hip arthroscopic techniques. METHODS: A retrospective series of 194 files of patients treated with hip arthroscopy in a tertiary hospital from December 1999 to March 2008 was reviewed for complications. The incidence of complications was recorded consecutively for each group of 30 patients and in intervals of 2 years. A comparison between the complication rates was performed within the time frames and the set of cases. The type and severity of complications were also recorded. RESULTS: There were 12 complications (6.1%) in this series. Of these, 5 were neurologic (2.6%), 4 were musculoskeletal (2%), and 3 were vascular/ischemic (1.5%). According to severity, 2 were considered major complications (1%), 8 were intermediate (4.1%), and 2 were minor (1%). The incidence of complications did not change with time (P = .959) or with the number of cases performed (P = .771), but different types of complications occurred along the learning curve. CONCLUSIONS: The nature of complications changed with experience, but no significant variation in the incidence was observed over the 9-year period of experience with hip arthroscopy. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Errata - Is it Important to Know Where to Place the Spherical Marker for Hip Replacement Digital Planning??

[This corrects the article DOI: 10.1055/s-0039-1693052.][This corrects the article DOI: 10.1055/s-0039-1693052.].

Femoroacetabular Impingement and Acetabular Labral Tears - Part 1: Pathophysiology and Biomechanics.

Femoroacetabular impingement (FAI) is an important cause of hip pain, and the main etiology of hip osteoarthritis in the young population. Femoroacetabular impingement is characterized by subtle alterations in the anatomy of the acetabulum and proximal femur, which can lead to labrum tearing. The acetabular labrum is essential to the stability of the hip joint. Three types of FAI were described: cam (anespherical femoral head), pincer (acetabular overcoverage) and mixed (characteristics of both cam and pincer). The etiology of FAI is related to genetic and environmental characteristics. Knowledge of this condition is essential to adequately treat patients presenting with hip pain.

Femoroacetabular Impingement and Acetabular Labral Tears - Part 3: Surgical Treatment.

In the last 15 years, the diagnosis of femoroacetabular impingement has become more frequent; with the advance of surgical indications, different techniques have been developed. Surgical treatment includes a wide variety of options, namely: periacetabular osteotomy, surgical hip dislocation, arthroscopy with osteochondroplasty via a small incision, modified anterior approach technique, and exclusively arthroscopic technique. The type of approach should be chosen according to the complexity of the morphology of the femoroacetabular impingement and to the surgeon's training. The techniques most used today are arthroscopy, surgical dislocation of the hip, and periacetabular osteotomy. The present article aims to describe the current main surgical techniques used to treat femoroacetabular impingement, their indications, advantages and disadvantages, complications and clinical results.

Femoroacetabular Impingement and Acetabular Labral Tears - Part 2: Clinical Diagnosis, Physical Examination and Imaging.

The clinical diagnosis of femoral acetabular impingement (FAI) continues to evolve as the understanding of normal and pathological hips progresses. Femoral acetabular impingement is currently defined as a syndrome in which the diagnosis consists of the combination of a previously-obtained comprehensive clinical history, followed by a consistent and standardized physical examination with specific orthopedic maneuvers. Additionally, radiographic and tomographic examinations are used for the morphological evaluation of the hip, and to ascertain the existence of sequelae of childhood hip diseases and the presence of osteoarthritis. The understanding of the femoral and acetabular morphologies and versions associated with images of labral and osteochondral lesions obtained through magnetic resonance imaging (MRI) contributes to the confirmation of this syndrome in symptomatic patients, and helps in the exclusion of differential diagnoses such as iliopsoas tendon snaps, subspine impingement, ischiofemoral impingement, and other hip joint pathologies.

Clinical and Radiographic Aspects of Patients with Femoroacetabular Impingement Syndrome: Is There Difference between Symptomatic and Asymptomatic Hip?

Objective This paper aims to compare clinical and radiographic features of symptomatic and asymptomatic hips in patients with unilateral femoroacetabular impingement syndrome (FAIS) and to establish a correlation between these findings. Methods This is a retrospective study, based on medical records of patients diagnosed with FAIS between January 2014 and April 2017. The patients were assessed clinically as per the International Hip Outcome Tool 33 (iHOT33) questionnaire, visual analogue pain scale, hip rotation, and hip and knee muscular strength. The radiographic evaluation consisted of measurements of the alpha angle, crossover signal, acetabular retroversion index, ischial spine signal, and posterior wall sign. Results A total of 45 patients were included in the study, with mean time from symptom onset to diagnosis of 28.6 months and mean iHOT33 score was 39.9. The mean medial rotation was 20.5° in symptomatic hip and 27.2° in asymptomatic hip ( p < 0.001). The crossover signal was positive on 68.9% of the symptomatic hips and 55.6% of the asymptomatic hips ( p = 0.03). The mean retroversion index was 0.15 in symptomatic hips and 0.11 in asymptomatic hips ( p = 0.02). There was a positive correlation between the total time of symptoms and medial hip rotation reduction ( p = 0.04) and between body mass index (BMI) and medial hip rotation reduction ( p = 0.02). Conclusion When comparing clinical and radiographic features, we observed reduction of medial rotation and increase of acetabular retroversion index in the symptomatic hip, as well as association between the long symptom time and the high BMI with loss of medial rotation of the hips.

Is it Important to Know Where to Place the Spherical Marker for Hip Replacement Digital Planning?

Objective The present paper aims to evaluate the influences of individual characteristics in radiographic magnification and to identify the most accurate method for radiographic calibration. Methods During radiographical exam of 50 patients with hip prosthesis, anthropometric data was collected and 4 spherical metal markers with 25 mm diameters were positioned: at the greater trochanter level and lateral to it, over the pubic symphysis, between the thighs at the greater trochanter level, and over the exam table. Since the prosthesis head is the best internal radiographic marker for hip arthroplasty, it was our calibration parameter. Two examiners measured the markers' image for further analysis. Results The sample consisted of 50 participants, 19 of whom were male. A difference in pubic symphysis magnification was found. Other individual characteristics (weight, height and body mass index) had weak correlation. The higher accuracy of the markers was at the greater trochanter, between 68.4 and 78.9%, visualized in only19 radiographs. The marker positioned between the thighs was visualized in all radiographs, with an accuracy ranging from 30 to 46%. Conclusions Of all individual characteristics, only gender influences magnification at the pubic symphysis. We suggest the use of two spherical markers: at the greater trochanter, due the best accuracy, and between the thighs, considered the best positioning for better visibility.