Pipkin Type-II Femoral Head Fracture: A Biomechanical Evaluation by the Finite-Element Method / Fratura da cabeça femoral de tipo II de Pipkin: Avaliação biomecánica pelo método de elementos finitos

Abstract Objective To evaluate the biomechanical capacity of two forms of fixation for Pipkin type-II fractures, describing the vertical fracture deviation, the maximum and minimum principal stresses, and the Von Mises equivalent stress in the syntheses used. Materials and Methods Two internal fasteners were developed to treat Pipkin type-II fractures through finite elements: a 3.5-mm cortical screw and a Herbert screw. Under the same conditions, the vertical fracture deviation, the maximum and minimum principal stresses, and the Von Mises equivalent stress in the syntheses used were evaluated. Results The vertical displacements evaluated were of 1.5mm and 0.5mm. The maximum principal stress values obtained in the upper region of the femoral neck were of 9.7 KPa and 1.3 Kpa, and the minimum principal stress values obtained in the lower region of the femoral neck were of-8.7 KPa and -9.3 KPa. Finally, the peak values for Von Mises stress were of 7.2 GPa and 2.0 GPa for the fixation models with the use of the 3.5-mm cortical screw and the Herbert screw respectively. Conclusion The fixation system with the Herbert screw generated the best results in terms of reduction of vertical displacement, distribution of the maximum principal stress, and the peak Von Mises equivalent stress, demonstrating mechanical superiority compared to that of the 3.5-mm cortical screw in the treatment of Pipkin type-II fractures.

Resumo Objetivo Avaliar a capacidade biomecánica de duas formas de fixação de fraturas tipo II de Pipkin descrevendo o desvio da fratura no sentido vertical, as tensões máxima e mínima principais, e a tensão equivalente de Von Mises nas sínteses utilizadas. Materiais e Métodos Dois fixadores internos foram desenvolvidos para tratar a fratura tipo II de Pipkin por meio de elementos finitos: parafuso cortical de 3,5 mm e parafuso de Herbert. Sob as mesmas condições, foram avaliados o desvio da fratura no sentido vertical, as tensões máxima e mínima principais, e a tensão equivalente de Von Mises nas sínteses utilizadas. Resultados Os deslocamentos verticais avaliados foram de 1,5 mm e 0,5 mm. Os valores de tensão máxima obtidos na região superior do colo femoral foram de 9,7 KPa e 1,3 KPa, e os valores de tensão mínima obtidos na região inferior do colo femoral foram de -8,7KPa e -9,3 KPa. Por fim, os valores de pico da tensão equivalente de Von Misesforam de 7,2 GPa e2,0 GPa paraosmodelos de fixação com o uso do parafuso cortical de 3,5 mm e do parafuso de Herbert, respectivamente. Conclusão Osistema de fixação com parafuso de Herbert gerou os melhores resultados em termos de redução do deslocamento vertical, distribuição da tensão máxima e do pico da tensão equivalente de Von Mises, o que demonstra sua superioridade mecânica comparada à do parafuso cortical de 3,5 mm no tratamento da fratura tipo II de Pipkin.

Imaging measurement and analysis of related indexes of variation of femoral head rotation center / 中国骨伤

OBJECTIVE@#To provide guidance for hip replacement by analyzing the variation of femoral head rotation center in different hip diseases.@*METHODS@#A total of 5 459 patients were collected from March 2016 to June 2021, who took positive and proportional plain films of both hips for various reasons. The relative position between the rotation center of the femoral head and the apex of the greater trochanter was measured. The positive variation is more than 2 mm above the top of the great trochanter, and the negative variation is more than 2 mm below the top of the great trochanter. A total of 831 patients with variation of femoral head rotation center were collected and were divided into 4 groups according to different diseases, and the variation was counted respectively. There were 15 cases in the normal group involving 10 cases of positive variation and 5 cases of negative variation. There were 145 cases of avascular necrosis of femoral head involving 25 cases of positive variation and 120 cases of negative variation. There were 346 cases of congenital hip dysplasia involving 225 cases of positive variation(including 25 cases of typeⅠ, 70 cases of type Ⅱ, 115 cases of type Ⅲ and 15 cases of type Ⅳ), and 121 cases of negative variation(including 50 cases of crowe typeⅠ, 60 cases of typeⅡ, 10 cases of type Ⅲ and 1 case of type Ⅳ). There were 325 cases of hip osteoarthritis group involving 45 cases of positive variation and 280 cases of negative variation.@*RESULTS@#There was significant difference in variation of femoral head rotation center among the four groups(P<0.05). There was significant difference in variation of femoral head rotation center among different types of congenital hip dysplasia(P<0.05). There were significant differences in cervical trunk angle and eccentricity among different variations of femoral head rotation center(P<0.05).@*CONCLUSION@#The variation of femoral head rotation center is related to cervical trunk angle and eccentricity. The variation of femoral head rotation center is an important factor in hip diseases. The variation of femoral head rotation center is different in different hip diseases. Avascular necrosis of the femoral head and osteoarthritis of the hip were mostly negative variations. With the aggravation of congenital hip dysplasia, the variation of femoral head rotation center gradually changed from negative variation to positive variation.The variation of femoral head rotation center should be paid attention to in the preoperative planning of hip arthroplasty. It is of great significance to select the appropriate prosthesis and place the prosthesis accurately.

Clinical study on core decompression in treating osteonecrosis of the femoral head of the necrotic bone-in different site / 中国骨伤

OBJECTIVE@#To analyze the clinical effect of decompression and bone grafting on osteonecrosis of the femoral head(ONFH) at different sites of necrotic lesions.@*METHODS@#A total of 105 patients with ARCOⅡstage ONFH admitted from January 2017 to December 2018 were retrospectively analyzed. There were 71 males and 34 females, with an average age of (55.20±10.98) years old. The mean course of all patients was(15.91±9.85) months. According to Japanese Inveatigation Committee (JIC) classification, all patients were divided into 4 types:17 cases of type A, 26 cases of type B, 33 cases of type C1 and 29 cases of type C2. All four groups were treated with decompression of the pulp core and bone grafting. Visual analogue scale(VAS) and Harris hip joint score were used before and at 3, 6, 12, and 24 months after the operation, and the collapse of the femoral head was observed by X-ray examination within 2 years.@*RESULTS@#All 105 patients were successful on operation without complications, and the mean follow-up duration was (24.45±2.75) months. Harris score showed that there was no statistical difference among four groups before surgery and 3, 6 months after surgery (P>0.05);at 12 and 24 months after surgery, there were significant differences among all groups (P<0.01). There were significant differences in intragroup Harris scores at preoperative and postoperative time points among four groups (P<0.01). VAS showed that there was no statistical difference among four groups before and 3, 6 months after surgery (P>0.05);at 12 and 24 months after surgery, there were significant differences among all groups (P<0.01). There were significant differences in VAS at preoperative and postoperative time points among four groups (P<0.01). None of the patients in four groups had femoral head collapse before and 3, 6 months after surgery. At 12 months after operation, there were 3 cases of femoral head collapse in group C and 4 cases in group C2(P>0.05);At 24 months after operation, 1 case of femoral head collapse occurred in group B, 6 cases in group C1 and 8 cases in group C2(P<0.05).@*CONCLUSION@#Core decompression and bone grafting can improve the effect of ONFH and hip preservation. The effect of hip preservation for ONFH is closely related to the location of the osteonecrosis lesion, so the influence of the location of lesion on the effect of hip preservation should be considered in clinical treatment, so as to make better preoperative hip preservation plan.

Assessment of the local blood supply when femoral neck fracture occurs:advances in the anatomy research and its clinical application / 中国骨伤

The stability of internal fixation of femoral neck fractures can be obtained through surgical techniques, the configuration of screws and bone grafting, etc. However, the blood supply injury caused by fractures could not be completely reversed by the current medical management. Hence, the comprehensive evaluation of the residual blood supply of the femoral neck, to perioperatively avoid further iatrogenic injury, has become a hotspot. The anatomy of the extraosseous blood supply of the femoral neck has been widely reported, while its clinical application mostly involved the assessment of the medial circumflex femoral artery and retinacular arteries. However, further studies are needed to explore the prognosis of patients with these artery injuries, with different degrees, caused by femoral neck fractures. Direct observations of nutrient foramina in vivo are not possible with current clinical technologies, but it is possible to make reasonable preoperative planning to avoid subsequent femoral head necrosis based on the distribution features of nutrient foramina. The anatomy and clinical application studies of the intraosseous blood supply focused on the junction area of the femoral head and neck to probe the mechanism of femoral head necrosis. Thus, the intraosseous blood supply of other regions in the femoral neck remains to be further investigated. In addition, a blood supply evaluation system based on a three-level structure, extraosseous blood vessels, nutrient foramina, and intraosseous vascular network, could be explored to assist in the treatment of femoral neck fractures.

A novel lateral classification of osteonecrosis of femoral head based on CT recons-truction of necrotic area and its clinical verification / 中国修复重建外科杂志

OBJECTIVE@#To analyze the femoral head collapse and the operation of osteonecrosis of the femoral head (ONFH) in different Japanese Investigation Commitee (JIC) types, in order to summarize the prognostic rules of each type of ONFH, and explore the clinical significance of CT lateral subtypes based on reconstruction of necrotic area of C1 type and verify their clinical effect.@*METHODS@#A total of 119 patients (155 hips) with ONFH between May 2004 and December 2016 were enrolled in the study. The total hips consisted of 34 hips in type A, 33 in type B, 57 in type C1, and 31 in type C2, respectively. There was no significant difference in age, gender, affected side, or type of ONFH of the patients with differenct JIC types ( P>0.05). The 1-, 2-, and 5-year femoral head collapse and operation of different JIC types were analyzed, as well as the survival rate (with femoral head collapse as the end point) of hip joint between different JIC types, hormonal/non-hormonal ONFH, asymptomatic and symptomatic (pain duration >6 months or ≤6 months), and combined preserved angle (CPA) ≥118.725° and CPA<118.725°. JIC types with significant differences in subgroup surgery and collapse and with research value were selected. According to the location of the necrotic area on the surface of the femoral head, the JIC classification was divided into 5 subtypes in the lateral CT reconstruction, and the contour line of the necrotic area was extracted and matched to the standard femoral head model, and the necrosis of the five subtypes was presented by thermography. The 1-, 2-, and 5-year outcomes of femoral head collapse and operation in different lateral subtypes were analyzed, and the survival rates (with collapse of the femoral head as the end point) between CPA≥118.725° and CPA<118.725° hip in patients with this subtype were compared, as well as the survival rates of different lateral subtypes (with collapse and surgery as the end points, respectively).@*RESULTS@#The femoral head collapse rate and operation rate in the 1-, 2-, and 5-year were significantly higher in patients with JIC C2 type than in patients with other hip types ( P<0.05), while in patients with JIC C1 type than in patients with JIC types A and B ( P<0.05). The survival rate of patients with different JIC types was significantly different ( P<0.05), and the survival rate of patients with JIC types A, B, C1, and C2 decreased gradually. The survival rate of asymptomatic hip was significantly higher than that of symptomatic hip, and the survival rate of CPA≥118.725° was significantly higher than that of CPA<118.725° ( P<0.05). The lateral CT reconstruction of type C1 hip necrosis area was selected for further classification, including type 1 in 12 hips, type 2 in 20 hips, type 3 in 9 hips, type 4 in 9 hips, and type 5 in 7 hips. There were significant differences in the femoral head collapse rate and the operation rate among the subtypes after 5 years of follow-up ( P<0.05). The collapse rate and operation rate of types 4 and 5 were 0; the collapse rate and operation rate of type 3 were the highest; the collapse rate of type 2 was high, but the operation rate was lower than that of type 3; the collapse rate of type 1 was high, but the operation rate was 0. In JIC type C1 patients, the survival rate of the hip joint with CPA≥118.725° was significantly higher than that with CPA<118.725° ( P<0.05). In the follow-up with femoral head collapse as the end point, the survival rates of types 4 and 5 were all 100%, while the survival rates of types 1, 2, and 3 were all 0, and the difference was significant ( P<0.05). The survival rate of types 1, 4, and 5 was 100%, of type 3 was 0, and of type 2 was 60%, showing significant difference ( P<0.05).@*CONCLUSION@#JIC types A and B can be treated by non-surgical treatment, while type C2 can be treated by surgical treatment with hip preservation. Type C1 was classified into 5 subtypes by CT lateral classification, type 3 has the highest risk of femoral head collapse, types 4 and 5 have low risk of femoral head collapse and operation, type 1 has high femoral head collapse rate but low risk of operation; type 2 has high collapse rate, but the operation rate is close to the average of JIC type C1, which still needs to be further studied.

Visual and quantitative assessment of the effectiveness of non-vascularized bone grafting in osteonecrosis of the femoral head via CT-based radiomics and clinical data / 中国修复重建外科杂志

OBJECTIVE@#To investigate the value of CT-based radiomics and clinical data in predicting the efficacy of non-vascularized bone grafting (NVBG) in hip preservation, and to construct a visual, quantifiable, and effective method for decision-making of hip preservation.@*METHODS@#Between June 2009 and June 2019, 153 patients (182 hips) with osteonecrosis of the femoral head (ONFH) who underwent NVBG for hip preservation were included, and the training and testing sets were divided in a 7∶3 ratio to define hip preservation success or failure according to the 3-year postoperative follow-up. The radiomic features of the region of interest in the CT images were extracted, and the radiomics-scores were calculated by the linear weighting and coefficients of the radiomic features after dimensionality reduction. The clinical predictors were screened using univariate and multivariate Cox regression analysis. The radiomics model, clinical model, and clinical-radiomics (C-R) model were constructed respectively. Their predictive performance for the efficacy of hip preservation was compared in the training and testing sets, with evaluation indexes including area under the curve, C-Index, sensitivity, specificity, and calibration curve, etc. The best model was visualised using nomogram, and its clinical utility was assessed by decision curves.@*RESULTS@#At the 3-year postoperative follow-up, the cumulative survival rate of hip preservation was 70.33%. Continued exposure to risk factors postoperative and Japanese Investigation Committee (JIC) staging were clinical predictors of the efficacy of hip preservation, and 13 radiomic features derived from least absolute shrinkage and selection operator downscaling were used to calculate Rad-scores. The C-R model outperformed both the clinical and radiomics models in predicting the efficacy of hip preservation 1, 2, 3 years postoperative in both the training and testing sets ( P<0.05), with good agreement between the predicted and observed values. A nomogram constructed based on the C-R model showed that patients with lower Rad-scores, no further postoperative exposure to risk factors, and B or C1 types of JIC staging had a higher probability of femoral survival at 1, 2, 3 years postoperatively. The decision curve analysis showed that the C-R model had a higher total net benefit than both the clinical and radiomics models with a single predictor, and it could bring more net benefit to patients within a larger probability threshold.@*CONCLUSION@#The prediction model and nomogram constructed by CT-based radiomics combined with clinical data is a visual, quantifiable, and effective method for decision-making of hip preservation, which can predict the efficacy of NVBG before surgery and has a high value of clinical application.

Primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement: A case report and surgical techniques / 中华创伤杂志(英文版)

For the treatment of an intertrochanteric fracture combined with femoral head necrosis in middle-age patients, it has been controversial whether to perform fracture reduction and fixation first then total hip replacement, or direct total hip replacement. We present a rare case of 53-year-old male patient suffered from bilateral intertrochanteric fracture caused by a road traffic injury. The patient had a history of femoral head necrosis for eight years, and the Harris score was 30. We performed total hip replacement with prolonged biologic shank prostheses for primary repair. One year after the surgery, nearly full range of motion was achieved without instability (active flexion angle of 110°, extension angle of 20°, adduction angle of 40°, abduction angle of 40°, internal rotation angle of 25°, and external rotation angle of 40°). The Harris score was 85. For the middle-aged patient with unstable intertrochanteric fractures and osteonecrosis of the femoral head, we can choose primary repair for concurrent bilateral intertrochanteric fracture and femoral head necrosis with prolonged shank biologic total hip replacement.

Finite element analysis for predicting osteonecrosis of the femoral head collapse based on the preserved angles / 中国修复重建外科杂志

OBJECTIVE@#To establish finite element models of different preserved angles of osteonecrosis of the femoral head (ONFH) for the biomechanical analysis, and to provide mechanical evidence for predicting the risk of ONFH collapse with anterior preserved angle (APA) and lateral preserved angle (LPA).@*METHODS@#A healthy adult was selected as the study object, and the CT data of the left femoral head was acquired and imported into Mimics 21.0 software to reconstruct a complete proximal femur model and construct 3 models of necrotic area with equal volume and different morphology, all models were imported into Solidworks 2022 software to construct 21 finite element models of ONFH with LPA of 45°, 50°, 55°, 60°, 65°, 70°, and 75° when APA was 45°, respectively, and 21 finite element models of ONFH with APA of 45°, 50°, 55°, 60°, 65°, 70°, 75° when LPA was 45°, respectively. According to the physiological load condition of the femoral head, the distal femur was completely fixed, and a force with an angle of 25°, downward direction, and a magnitude of 3.5 times the subject's body mass was applied to the weight-bearing area of the femoral head surface. The maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head were calculated and observed by Abaqus 2021 software.@*RESULTS@#The finite element models of ONFH were basically consistent with biomechanics of ONFH. Under the same loading condition, there was stress concentration around the necrotic area in the 42 ONFH models with different preserved angles composed of 3 necrotic areas with equal volume and different morphology. When APA was 60°, the maximum Von Mises stress of the surface of the femoral head and the necrotic area and the maximum displacement of the weight-bearing area of the femoral head of the ONFH models with LPA<60° were significantly higher than those of the models with LPA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with LPA≥60° ( P>0.05). When LPA was 60°, each index of the ONFH models with APA<60° were significantly higher than those of the models with APA≥60° ( P<0.05); there was no significant difference in each index among the ONFH models with APA≥60° ( P>0.05).@*CONCLUSION@#From the perspective of biomechanics, when a preserved angle of ONFH is less than its critical value, the stress concentration phenomenon in the femoral head is more pronounced, suggesting that the necrotic femoral head may have a higher risk of collapse in this state.

Case-control study on robot-assisted core decompression and conventional core decompression for early necrosis of femoral head / 中国骨伤

OBJECTIVE@#To compare clinical effect of robot-assisted core decompression and conventional core decompression in treating ARCO Ⅰ stage necrosis of femoral head.@*METHODS@#A retrospective analysis was performed on 60(unilateral operation) patients who underwent core decompression for femoral head necrosis from February 2018 to February 2020. Among them, 30 patients(30 hips) were underwent robot-assisted core decompression (RCD group), including 19 males and 11 females, aged from 17 to 58 years old with an average of(38.50±10.61) years old;30 patients(30 hips) were underwent traditional core decompression surgery (CCD group), including 20 males and 10 females, aged from 20 to 55 years old with an average of (40.63±10.63) years old. Intraoperative fluoroscopy times, intraoperative blood loss and operation time between two groups, and Harris score, visual analogue scale (VAS) before opertaion and 24 months after operation were compared.@*RESULTS@#All patients were followed up, RCD group followed up from 21 to 26 months with an average of(23.40±1.65) months, CCD group followed up from 21 to 26 months with an average of (23.30±1.66) months, and had no difference between two groups(P>0.05). The number of intraoperative X-ray fluoroscopy, intraoperative blood loss and operative time in RCD group were (9.43±1.14) times, (153.80±22.04) ml, (33.40±1.87) min, respectively;while(19.67±1.32) times, (165.04±20.41) ml and (54.75±3.46) min in CCD group respectively;and there were statistical difference between two groups(P<0.05). In addition, there were no statistical difference between two groups in Harris score and VAS at 24 months after operation(P>0.05).@*CONCLUSION@#Compared with conventional core decompression, robot-assisted core decompression could reduce the number of intraoperative fluoroscopy, shorten operation time, and reduce risk of surgery.

Epidemiología, resultados clínicos y tasa de éxito en cirugía preservadora de cadera en la necrosis avascular de cabeza femoral / Epidemiology, clinical results and success rate in hip preservation surgery in avascular osteonecrosis of the femoral head

Resumen: Introducción: La necrosis avascular de cabeza femoral (NACF) es una patología frecuente que en sus inicios es asintomática y se manifiesta de forma insidiosa, por lo que a menudo el diagnóstico se realiza en estadios avanzados, donde la única solución eficaz es la artroplastía total de cadera (ATC). El diagnóstico en fases precoces permitirá utilizar opciones terapéuticas que eviten o retrasen la ATC. Nuestro objetivo es valorar los resultados demográficos, clínicos y la tasa de éxito en nuestro centro de pacientes con diagnóstico de NACF y que han sido subsidiarios de cirugía de preservación de cadera. Material y métodos: Estudio clínico unicéntrico, prospectivo, no controlado de pacientes con diagnóstico de NACF entre Enero de 2012 y Septiembre de 2017 con un estadio Steinberg ≤ IIIA. La técnica quirúrgica utilizada es el forage descompresivo, asociado a relleno con aloinjerto y aspirado de médula ósea. Resultados: Se intervinieron 26 caderas con nuestra técnica quirúrgica. La tasa de éxito obtenida es de 61.54%, ya que 10 casos han precisado ATC durante el estudio (38.46%). Conclusión: El éxito terapéutico en la NACF está directamente relacionado con el grado de la enfermedad, por lo que es importante el diagnóstico precoz. El forage descompresivo con relleno de aloinjerto que asocia aspirado de médula ósea es una opción a tener en cuenta, ya que en estadios iniciales muestra una elevada tasa de éxito.

Abstract: Introduction: Avascular osteonecrosis of the femoral head (ONFH) is a frequent pathology with an insidious and asymptomatic presentation in early stages, so the diagnosis is often made in advanced stages, where the only effective solution is total hip arthroplasty (THA). Diagnosis in early stages will allow the use of therapeutic options that avoid or delay ATC. Our objective is to evaluate the demographic, clinical results and the success rate in our center of patients diagnosed with ONFH and who have been subsidiary of hip preservation surgery. Material and methods: Unicentric, prospective, uncontrolled clinical study of patients diagnosed with ONFH between January 2012 and September 2017 with a Steinberg ≤ IIIA stage. The surgical technique used is decompressive forage, associated with bone allograft and bone marrow aspiration. Results: 26 hips were operated on with our surgical technique. The success rate obtained is 61.54%, since 10 cases have required THA during the study (38.46%). Conclusions: The therapeutic success in ONFH is directly related to the degree of the disease, which is why early diagnosis is important. The decompressive forage with bone allograft that associates bone marrow aspiration is an option to be taken into account, since in early stages it shows a high success rate.

Platelet-rich plasma combined with core decompression and bone grafting in the treatment of non traumatic necrosis of femoral head in ARCO stageⅡ / 中国骨伤

OBJECTIVE@#To observe the clinical effect of platelet rich plasma (PRP) combined with β tricalcium phosphate bioceramic bone in the treatment of non traumatic necrosis of the femoral head in ARCO stageⅡ.@*METHODS@#From January 2017 to December 2018, 100 patients (160 hips) with ARCO stageⅡnon traumatic necrosis of the femoral head were divided into PRP group and control group. In PRP group, 50 patients (80 hips), 22 males and 28 females, aged from 18 to 65 (43.47± 7.23) years, with a course of 4 to 18 (15.8±2.9) months, underwent core decompression and bone grafting combined with PRP implantation. There were 50 cases (80 hips) in the control group, including 27 males and 23 females, aged 20 to 63 (45.72± 7.43) years, and the course of disease was 6 to 19 (14.9±3.8) months. Hip X-ay film was followed up after operation. Harris score and VAS score were used to evaluate the curative effect, and the survival rate of hip joint was recorded.@*RESULTS@#All patients had good wound healing, no infection, thrombosis and other complications. All patients were followed up for 12 to 14 (12.0±0.4) months. Twelve months after operation, the image expression of PRP group was better than that of control group(@*CONCLUSION@#Platelet-rich plasma(PRP) combined with artificialbone for core decompression and bone grafting can change the situation of simple artificial bone implantation and uncertain curative effect, improve the success rate of this operation, effectively reduce the collapse rate of femoral head necrosis in the early and middle stage, delay or even avoid hip replacement.

Femoral pseudoaneurysm as a complication of slipped capital femoral epiphysis treatment / Pseudoaneurisma femoral como complicação do tratamento cirúrgico de epifisiólise proximal do fêmur

ABSTRACT Slipped capital femoral epiphysis is a very frequently seen condition in orthopedics centers worldwide. Even in successfully treated cases, complications related either with the pathology per se or with the chosen synthesis method are not rare. This report presents a case of bilateral slipped capital femoral epiphysis treated with pinning, in which one of the limbs developed a very rare condition: the formation of a femoral pseudoaneurysm that ruptured.

RESUMO A epifisiólise proximal da cabeça femoral é uma patologia frequentemente tratada em centros de ortopedia. Mesmo nos casos de tratamento bem-sucedido, complicações relacionadas tanto ao fenômeno em si quanto à síntese escolhida não são raras. Os autores relatam um caso de epifisiólise da cabeça femoral bilateral, submetido a pinagem, que evoluiu com uma complicação raríssima em um dos membros: a formação de um pseudoaneurisma femoral, com posterior rotura.

Stem Cell Therapy for the Treatment of Hip Osteonecrosis: A 30-Year Review of Progress

Avascular necrosis of the femoral head is caused by a multitude of etiologic factors and is associated with collapse with a risk of hip arthroplasty in younger populations. A focus on early disease management with the use of stem cells was proposed as early as 1985 by the senior author (PH). We undertook a systematic review of the medical literature to examine the progress in cell therapy during the last 30 years for the treatment of early stage osteonecrosis.

Comparison of the Sliding and Femoral Head Rotation among Three Different Femoral Head Fixation Devices for Trochanteric Fractures

BACKGROUND: Recently, various femoral head fixation devices (HFDs) for trochanteric fractures have become available. However, there are some cases in which femoral head rotation with excessive sliding of the HFD is observed and it is often followed by cutout. The purpose of this study is to compare the ability of the three types of HFDs to prevent femoral head rotation. METHODS: Between July 2005 and December 2009, 206 patients aged over 60 years with trochanteric fractures who had undergone surgical treatment using a short femoral nail in our institution were enrolled into the study. We used the gamma 3 nail (GMN) as the screw-type HFD in 66 cases, the gliding nail (GLN) as a non-cylindrical blade in 76 cases, and the proximal femoral nail antirotation (PFNA) as a cylindrical blade in 64 cases. The sliding length of HFDs and the occurrence of femoral head rotation were evaluated by assessing radiographs as the main outcome, and the results were compared among these devices. RESULTS: A comparison of the degree of sliding in the GMN group showed that femoral head rotation was observed significantly more frequently in cases with rotation. Further, it appeared that femoral head rotation occurred more frequently in comminuted fractures. However, no significant differences between the sliding lengths of the different HFDs were observed among three groups. Femoral head rotation was observed in 15 cases of GMN (22.7%), 0 case of GLN, and 5 case of PFNA (7.8%). Significant differences with regard to the occurrence of femoral head rotation were observed among the three groups. Furthermore, significant differences were also observed between GLN and PFNA with respect to the occurrence of femoral head rotation. CONCLUSIONS: The ability to stabilize femoral head appears to be greater with blade-type materials than with screw-type materials. Furthermore, we believe that a non-cylindrical blade is preferable to a cylindrical blade for the surgical treatment of comminuted, unstable trochanteric fractures in order to prevent femoral head rotation and cut-out.

Total hip replacement in two dogs with unsuccessful femoral head ostectomy

An English setter (case 1) and a Tibetan mastiff (case 2) presented with intermittent weight-bearing lameness on the right hind limb when trotting. The dogs had a history of femoral head and neck ostectomy (FHNO). Orthopedic examination revealed pain and crepitus on the right hip joint. The dogs underwent total hip replacement (THR). At the 2-year (case 1) and 1-year (case 2) follow-up, both dogs had resumed normal activity without lameness. The muscle mass and range of motion were significantly improved in the affected hind limb. In conclusion, FHNO with poor functional outcomes can be successfully ameliorated with THR.

Remodelación y deterioro en epifisiolisis de cadera después de la fijación in situ. Resultados preliminares / Slipped capital femoral epiphysis remodeling and deterioration after in situ fixation. Preliminary results

Introducción: Una vez detenida la progresion del deslizamiento, las caderas experimentan un fenomeno complejo de remodelacion. Mientras tanto, el choque femoro-acetabular provoca daño irreversible del cartilago articular. El proposito del trabajo es determinar si la remodelacion es suficiente para impedir el deterioro articular en el corto plazo. Materiales y Métodos: Se diseñó un estudio de cohorte retrospectivo de pacientes con deslizamientos moderados y graves, que recibieron como tratamiento la fijacion in situ. Se evaluó la capacidad de remodelación con el ángulo de Southwick y el ángulo alfa. El deterioro funcional se evaluó con el puntaje de Harris y el radiologico, con la escala de Tonnis. Seguimiento minimo: 4 años. Resultados: Diecisiete pacientes, mediana de seguimiento: 63 meses (Ri 55-81). El angulo de Southwick prequirurgico 57o (Ri 50-72) versus el posquirurgico 48o (Ri 45-74) disminuyó significativamente (p 0,023). lo mismo ocurrio con el angulo alfa complementario. El deterioro radiologico evaluado con la escala de Tonnis fue estadisticamente significativo (p 0,012). los resultados funcionales, cuantificados con el puntaje de Harris no mostraron diferencias estadisticamente significativas (p 0,49). Conclusiones: En esta serie, las epifisiolisis moderadas y graves fijadas in situ presentaron deterioro radiologico en 63 meses de seguimiento promedio. Sin embargo, la funcionalidad no se deterioro con la misma rapidez. Nivel de Evidencia: IV.

Background: After stopping the slip progression, hips undergo a remodeling complex phenomenon. Meanwhile femoro-acetabular shock causes irreversible joint cartilage damage. The purpose of the study is to determine if remodeling is sufficient to prevent joint deterioration in the short-term. Methods: a retrospective cohort study of patients with moderate and severe landslides, treated with in situ fixation was designed. Remodeling capacity was evaluated with Southwick angle and alpha angle. Functional and radiological impairment was evaluated with the Hip Harris Score and Tonnis scale, respectively. Minimum follow-up: 4 years. Results: Seventeen patients, median follow-up 63 months (iR 55-81). The pre-surgical Southwick angle 57o (iR 50-72) versus the postoperative one 48o (iR 45-74) significantly decreased (p 0.023). The same happened with the complementary angle alpha. The radiological deterioration was statistically significant (p 0.012). Functional results showed no statistically significant differences (p 0.49). Conclusions: in this series, moderate and severe slipped capital femoral epiphysis fixed in situ showed radiological deterioration during a 63-month follow-up. However, the functionality is not deteriorating as quickly. Level of Evidence: IV.

Fracturing of revision of a cobalt-chrome femoral head after fracturing of a ceramic femoral head, with diffuse metallosis. Case report

We presente a case of a fracture of a cobalt-chrome femoral head after revision of a hip total prosthesis with ceramic femoral head fracture. During surgery we found the cobalt-chrome femoral head fracture, wear of the polyethylene and massive metallosis in muscular and cartilaginous tissue. Both femoral stem and acetabular cup were stable and without apparent wearing. After surgical debridement, we promoted the substitution of the femoral head and the acetabular polyethylene by similar ones. After 12 months of follow-up, the patient has no pain complaints, function limit or systemic signs associated with malign metallosis.

Effects of intertrochanteric varus osteotomy on Norberg angle and percent coverage of the femoral head in displastic dogs

This study was conducted to assess the effects of femoral varus osteotomy on joint congruency in dogs affected by early stage hip dysplasia. Preoperative planning to move the femoral head within the acetabulum was carried out. Varisation of the femoral inclination angle (fIA) was achieved by Intertrochanteric Osteotomy (ITO). Norberg angle (NA), percent coverage (PC) of the femoral head by the acetabulum and fIA was measured from preoperative, immediate postoperative and first and second recheck radiographs of seven dogs that underwent an ITO (joint n = 9). There was significant (p < 0.05) improvement of both NA and PC in all patients as indicated by a change in the mean +/- standard deviation of 78.9degrees +/- 7.5 and 36.9% +/- 5.2 to 92.2degrees +/- 6.7 and 50.6% +/- 8.3, respectively. No significant difference (p < 0.05) was observed between the values of the planned femoral inclination angle (pfIA) of the femur and the effective femoral inclination angle (efIA) obtained after surgery (115.9degrees +/- 2.5 and 111.3degrees +/- 6.4, respectively). These findings could encourage the use of ITO in veterinary practice and indicate that intertrochanteric varus osteotomy should be re-considered for the treatment of early stage hip dysplasia in dogs with radiological signs of joint incongruency.

Elegibilidade da cirurgia do tipo resurfacing na artroplastia do quadril: uma avaliação de 592 quadris / Eligibility for the hip-resurfacing arthroplasty procedure: an evaluation on 592 hips

OBJETIVO: Verificar a porcentagem de pacientes ideais elegíveis à cirurgia do tipo resurfacing do quadril em um serviço referência de artroplastias do quadril. MÉTODOS: Analisamos, dentre todos os casos de artroplastia do quadril realizadas no Hospital do Servidor Público Estadual de São Paulo (HSPE) entre janeiro de 2009 e dezembro de 2010, um total de 592 artroplastias, as quais se enquadrariam nos critérios de indicação ideal para artroplastia de resurfacing segundo avaliação clínica e radiológica preconizada com os critérios estabelecidos pela Food and Drug Administration (FDA) e por Seyler et al. RESULTADOS: Considerando o universo total das artroplastias de substituição do quadril, foram elegíveis 5,74% dos pacientes. Nos pacientes submetidos à artroplastia primária, encontrou-se 8,23% em condições ideais a este procedimento. CONCLUSÃO: Demonstra-se o papel ainda restrito desta modalidade cirúrgica entre as cirurgias do quadril.

OBJECTIVE: To investigate the percentage of ideal patients who would be eligible for hip-resurfacing surgery at a reference service for hip arthroplasty. METHODS: Out of all the cases of hip arthroplasty operated at Hospital do Servidor Público Estadual de São Paulo (HSPE) between January 2009 and December 2010, we assessed a total of 592 procedures that would fit the criteria for indication for resurfacing arthroplasty, after clinical and radiological evaluation according to the criteria established by the Food and Drug Administration (FDA) and by Seyler et al. RESULTS: Among the total number of hip replacement arthroplasty cases, 5.74% of the patients were eligible. Among the patients who underwent primary arthroplasty, we found that 8.23% presented ideal conditions for this procedure. CONCLUSION: The study demonstrated that this type of surgery still has a limited role among hip surgery methods.

Análisis experimental del desgaste entre UHMWPE y acero inoxidable 316l empleados en la manufactura de prótesis coxofemorales / Experimental wear analysis of UHMWPE and stainless 316l used in the manufacturing of coxofemoral prosthesis

La causa más común de falla en prótesis coxofemorales es el aflojamiento entre los componentes que conforman el sistema, de manera específica la copa acetabular y la cabeza femoral. En esta investigación se presenta un análisis tribológico del desgaste en los componentes mencionados, ya que cuando las superficies en contacto se desgastan, la funcionalidad mecánica del sistema se compromete, debido al cambio de geometría de los mismos, dando como resultado un juego mecánico entre la copa y la cabeza. Los materiales considerados en este estudio son el polietileno de ultra elevado peso molecular (UHMWPE, por sus siglas en inglés) para la copa acetabular, y acero inoxidable 316L para la cabeza femoral. Esta combinación de materiales representa hoy en día la recomendación más usual por parte de los cirujanos para pacientes de la tercera edad. La tasa anual de desgaste se determinó de manera experimental y se cuantificó la cantidad de material desprendido durante el contacto. Se establecieron las condiciones de carga de forma analítica, considerando las que actúan sobre la cabeza femoral a lo largo del área de desgaste durante la marcha humana. Posteriormente, se realizó el análisis experimental de desgaste utilizando una máquina tribológica de configuración perno-sobre-disco (pin-on-disk), diseñada de manera específica para este estudio. Las pruebas para determinar la pérdida volumétrica de los componentes se realizaron bajo tres condiciones de operación: en seco, lubricada con agua destilada y lubricada con suero bovino. El marco experimental considerado consistió en pernos de UHMWPE sobre discos de acero inoxidable 316l simulando el desgaste equivalente a diez años de uso de la prótesis. Finalmente, de los resultados obtenidos se puede establecer que el desgaste y la cantidad de partículas desprendidas disminuyen considerablemente cuando se utiliza suero bovino como lubricante para replicar las condiciones reales de operación del sistema...

The most common cause of failure in coxofemoral prostheses is the loosening between the components of the system, namely the acetabular cup and the femoral head. In this work a tribologic analysis of wear suffered in the components is presented, due to when the surfaces in contact are worn, the mechanical function of the system is compromised as the wearing implies a change in the geometry of the components, thus in their dimensions, resulting on a looseness between the cup and the head. The materials considered in this study are Ultra High Molecular Weight Polyethylene (UHMWPE) for the cup and 316L Stainless Steel for the femoral head, which represent the surgeons choice for elderly patients. The annual wearing rate between these components was experimentally determined, as well as the amount of debris produced during contact. Firstly, the loading conditions were determined analytically considering those acting on the femoral head taking into consideration the wearing area during human walk. Secondly, the experimental analysis consisted in wearing tests using a tribology pin-on-disk machine, specifically built for this study. The tests to determine the volumetric loss of the components were performed under three different operational conditions: dry, lubricated with bovine serum and lubricated with destilated water. The experimental set up consisted on UHMWPE pins and 316L Stainless steel discs simulating the equivalent wear of ten years of usage of the prostheses. Lastly, the obtained results proved that using the bovine serum as lubricant the wear and debris of the components was significantly reduced when compared with other cases, being the dry scenario where more damage was produced. It is important to point out that the bovine serum was chosen to simulate the synovial fluid in which the system is embedded.