Proximal Femoral Anatomy Research Articles

An Extended Trochanteric Osteotomy Is Necessary for the Removal of Broken Modular Metaphyseal Engaging Femoral Stems

BackgroundModular metaphyseal engaging (MME) femoral components in total hip arthroplasty (THA) allow optimized femoral length, offset, and anteversion and are useful in patients with unusual proximal femoral anatomy. Fretting, corrosion, and stem fractures above the modular sleeve are complications associated with these implants. The purpose of this study was to identify failure mechanisms of retrieved MME femoral components at our institution, identify all broken stem cases, and evaluate how often an extended trochanteric osteotomy (ETO) was required for removal. MethodsAll consecutively retrieved MME femoral components from September 2002 to May 2023 were reviewed. Patient demographics, procedure information, component specifications, indications for removal, and requirements for further revision surgery were reviewed. Descriptive statistics were calculated for variables of interest. ResultsThere were 131 retrieved MME components. The mean age at surgery was 59 years (range, 28 to 75), 49% were women, mean body mass index was 29.4 (range, 20.7 to 33.3), and mean American Society of Anesthesiologists score was 2.4 ± 0.5. There were 102 (78%) stems of 1 design (stem A), and 29 (22%) stems of a different design (stem B). Of 131 components, 10 (7.6%) failed secondary to stem fracture proximal to the modular sleeve. Four of 102 (4%) of stem A and 6 of 29 (21% of stem B) fractured. All broken stems required additional intervention for removal during revision THA, using an ETO (N = 9) or cortical window (N = 1) in which an intraoperative proximal femoral fracture occurred. ConclusionsBroken MME stems present a challenge for orthopaedic surgeons during revision THA. When a stem fracture occurs above the ingrown sleeve, the distal splines may have osseous interdigitation into the clothespin. Thus, when revising a broken MME stem, an ETO should be performed, and the segment should be long enough to allow distal access.

The Medium- to Long-Term Results of Vascular-Sparing Subcapital Osteotomy (VASSCO) for Pediatric Patients with Chronic Slipped Capital Femoral Epiphysis.

Background: In patients affected by chronic slipped capital femoral epiphysis (C-SCFE), the performance of a subcapital osteotomy is an effective procedure to correct the deformity at the proximal femur. However, the rate of postoperative complications is very high, with iatrogenic avascular necrosis of the femoral head (AVN) being the most bothersome. To overcome the risk of AVN, the modified Dunn procedure according to Ganz and, more recently, the Vascular Sparing Subcapital Osteotomy (VASSCO) technique have been proposed; however, only short-term follow-up studies are available on the latter technique being used. The aim of this study is therefore to show our mid-term clinical and radiological results with the VASSCO technique. Materials and Methods: A total of 26 patients underwent VASSCO for moderate or severe stable C-SCFE between 2012 and April 2016 with an average 10-year follow-up (range 8-12 years). The outcomes was evaluated using the HHS and pre- and postoperative ROM. The radiological outcomes and complications were collected. Results: No major intraoperative complications occurred; three patients reported postoperative transient apraxia of the lateral femoral cutaneous nerve, which completely recovered in six months. All the radiological outcomes showed substantial improvement postoperatively. One case patient developed AVN of the femoral head and required a total hip arthroplasty after 12 years. Conclusions: The current data suggest that VASSCO osteotomy is a reliable technique with very good clinical results at mid-term follow-up; it could be considered a valuable alternative to using more complex techniques to restore the proximal femoral anatomy in moderate to severe C-SCFE.

Utility of 3D Planning Software in Understanding Residual Proximal Femoral Deformity for Planning of Revision Hip Arthroscopy

Background: During the early evolution of femoroacetabular impingement (FAI) treatment, undercorrection of femoral deformity was a leading cause of hip arthroscopy failures. As the pendulum has swung, overresection of femoral deformity has increased in prevalence as a cause of persistent hip pain after arthroscopy. Computed tomography (CT) scans are increasingly being used in hip arthroscopy for preoperative planning purposes and may allow for improved 3-dimensional (3D) assessment of complex femoral deformities after previous femoroplasty. Purpose: To assess whether CT scans provide additional utility over standard radiographs in understanding proximal femoral morphology in patients being evaluated for revision hip arthroscopy after previous femoroplasty in the setting of FAI. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: Preoperative CT scans and standard radiographs were obtained in 80 patients who underwent revision hip arthroscopy for FAI. The anteroposterior and Dunn radiographic views were used to assess patients for residual proximal femoral deformity and were compared with the CT scan views using a commercially available software program. Determinations of underresection were made using alpha angle, while overresection was determined according to a previously described technique. Chi-square tests were performed to determine statistical significance between radiographic and CT classifications of overresection, underresection, and concomitant over- and underresection. A kappa value was calculated to determine the agreement between measurements on the radiographs and CT scans. Results: There were 30 patients (37.5%) for whom the CT scans revealed information about femoral morphology that was not detected on the radiographs. The kappa value of agreement was 0.28 between CT and radiographic measurements. Underresected cams were detected in 30 patients (37.5%) on CT scans versus 17 patients (21.3%) on radiographs (P = .024). Overresected cams were detected in 31 patients (38.8%) on CT scans versus 14 patients (17.5%) on radiographs (P = .0049). Concomitant areas of under- and overresection were detected in 12 patients (15.0%) on CT scans versus 3 patients (3.8%) on radiographs (P = .027). Conclusion: CT scans with 3D planning software may be more sensitive than traditional radiographic views at detecting aberrant proximal femoral anatomy in the setting of failed FAI surgery. The use of 3D planning software may be considered as an adjunctive tool to better understand complex deformity in the proximal femur for the planning of revision hip arthroscopy.

Analysis of factors associated with the influence of femoral stem anteversion after total hip arthroplasty

To explore the related factors of femoral stem anteversion (FSA) after total hip arthroplasty (THA), so as to provide reference for clinical design of FSA before operation and reduce the risk of hip dislocation after arthroplasty. Ninty-three patients (103 hips) who underwent THA between October 2021 and September 2022 and met the selection criteria were selected as the study subjects. Among them, there were 48 males and 45 females with an average age of 58.5 years (range, 25-88 years). Body mass index was 18.00-37.84 kg/m 2, with an average of 24.92 kg/m 2. There were 51 cases (57 hips) of osteonecrosis of femoral head, 35 cases (39 hips) of hip osteoarthritis, and 7 cases (7 hips) of congenital hip dysplasia. Based on CT images, the following indicators were measured: preoperative femoral neck anteversion (FNA), preoperative femoral rotation angle (FRA), preoperative acetabular anteversion (AA), and preoperative combined anteversion (CA; the sum of preoperative FNA and AA); postoperative FSA and the change in femoral anteversion angle (the difference between postoperative FSA and preoperative FNA). Based on preoperative X-ray films, the following indicators were measured: femoral cortical thickness index (CTI) and canal flare index (CFI), the proximal femoral medullary cavity was classified according to Noble classification (champagne cup type, normal type, chimney type), neck-shaft angle (NSA), and femoral offset (FO). Pearson correlation analysis, one-way ANOVA, and Point-biserial correlation analysis were used to investigate the correlation between postoperative FSA, postoperative change in femoral anteversion angle, and patient diagnosis, proximal femoral medullary cavity anatomy type, gender, age, as well as preoperative FNA, FRA, AA, CA, NSA, FO, CTI, and CFI. FSA was used as the dependent variable and the independent variables that may be related to it were included for multiple linear regression analysis. Based on CT image measurement, preoperative FNA was (15.96±10.01)°, FRA (3.36±10.87)°, AA (12.94±8.83)°, CA (28.9±12.6)°, postoperative FSA (16.18±11.01)°, and postoperative change in femoral anteversion angle was (0.22±9.98)°. Based on preoperative X-ray films measurements, the CTI was 0.586±0.081; the CFI was 4.135±1.125, with 23 hips classified as champagne cup type, 68 hips as normal type, and 12 hips as chimney type in the proximal femoral medullary cavity anatomy; NSA was (132.87±7.83)°; FO was (40.53±10.11) mm. There was no significant difference between preoperative FNA and postoperative FSA ( t=-0.227, P=0.821). Pearson correlation analysis showed that postoperative FSA was positively correlated with preoperative FNA, preoperative CA, postoperative change in femoral anteversion angle, and age ( P<0.05), while negatively correlated with preoperative FRA ( P<0.05). The postoperative change in femoral anteversion angle were positively correlated with preoperative FRA and postoperative FSA ( P<0.05), and negatively correlated with preoperative CA and FNA ( P<0.05). One-way ANOVA analysis showed that the above two indicators were not correlated with diagnosis and the proximal femoral medullary cavity anatomy type ( P>0.05). Multiple linear regression analysis showed a linear correlation between FSA and FNA, CA, age, and FRA ( F=10.998, P<0.001), and the best fit model was FSA=0.48×FNA-2.551. The factors related to FSA after THA include patient's age, preoperative FNA, CA, FRA and postoperative femoral anteversion, of which preoperative FNA is the most closely related. When designing a surgical plan before surgery, attention should be paid to the patient's preoperative FNA, and if necessary, CT around the hip joint should be scanned to gain a detailed understanding of the proximal femoral anatomical structure.

Functional outcome of intertrochanteric fractures treated with trochanteric stabilizing plates

Background: Intertrochanteric fractures account for significant percentage of health care costs and result in high rates of morbidity and mortality. Since higher rate of mortality and complications most fractures can be successfully treated with trochanteric stabilizing plates. This study was conducted to assess functional outcome in intertrochanteric fracture femur treated with trochanteric stabilizing plates and define ideal mode of fixation for such fractures. Trochanter stabilizing plate (TSP) is modular extension of dynamic hip screw (DHS) that is mounted on lateral femoral wall to stabilize greater trochanter. It provides the flexibility to achieve plate to bone apposition as well as axial compression or angular stability because of three screw fixations at the proximal fragment. TSF can provide a stress shield for the lateral trochanteric wall and prevent lateral migration of proximal fragments. Thus, TSF does not fail at the screw bone interface and provide a strong anchor in osteoporotic bone. The multiple locking screw holes of the TSF provide various options to tackle complex fracture pattern. It functions as an internalized external fixator and minimizes the pressure on the periosteum and encourages biological healing. Methods: A total of 30 subjects of intertrochanteric fractures undergoing treatment with trochanteric stabilizing plates were taken up for the study after informed consent. Results: Significant results were obtained using Harris hip score (HHS) at different postoperative follow up time intervals with good outcome and low complication rate. Conclusions: Trochanteric buttress plate creates biomechanically stable construct by incorporating the comminuted trochanter it restores the proximal femoral anatomy, ensuring anatomical reduction hence subsequently reduces limb length discrepancy. We thus conclude this is an effective technique and has excellent functional and radiological outcomes with minimal complication and early rehabilitation rates. As Intertrochanteric fractures of the hip is a very common condition affecting a large number of patients of variable demographics and racial background, a more widespread study is required for a more conclusive study.

Femoroacetabular impingement in ancient Nubia 1400-656 BC.

There is significant recent interest in femoroacetabular impingement (FAI) in orthopaedics. The etiology of the cam deformity is unknown but has been hypothesized to be due to stresses from sporting activities in our modern society. Few archeological studies exist of femora and FAI. This study reviewed proximal femoral anatomy in a skeletal collection from the ancient Nile valley archeological site at Tombos 1400-656 BC. Digital photographs of the femora were used to obtain angular measurements of the apparent neck shaft, true neck shaft, version, inclination, and α and β angles of Nötzli. All photographs were reviewed by two orthopaedic surgeons for cam and pincer lesions. Sex and age of the specimens was determined when possible. A cam lesion was defined as any femur demonstrating an α angle > 50° or when a cam deformity was seen on visual inspection by both orthopaedic surgeons. Pincer lesions were identified upon visual inspection by both orthopaedic surgeons, when the femoral neck demonstrated impaction lesions, as pelvis radiographs could not be obtained. There were 126 unique femora; 69 female and 57 male. Age estimates were possible in 100 and was 15-24years in 14, 25-34years in 33, 35-49years in 28, 50-69years in 17, and ≥ 70years in 8. There were nine femora (seven individuals) with cam lesions (7%) and five femora (four individuals) with pincer lesions (4%). One demonstrated a combined lesion. FAI existed in ancient Nile valley inhabitants and is thus not only a product of modern day life style athletics. This contrasts with Native Americans living in Ohio 700-1000 AD where no FAI was identified. This difference is likely due to combinations of different types of activity, diet, and genetics. Further research of ancient populations is needed to further answer this question. IV-cohort study.

Outcome of the Wagner Cone femoral component for difficult anatomical conditions during total hip arthroplasty.

Total hip arthroplasty (THA) in patients with small or unusual proximal femoral anatomy is challenging due to sizing issues, control of version, and implant fixation. The Wagner Cone is a monoblock, fluted, tapered stem with successful outcomes for these patients; however, there is limited information on subsidence, a common finding with cementless stems. We retrospectively reviewed our cases using the modified Wagner Cone (Zimmer, Warsaw, IN) implanted over a 13-year period (2006-2019) in patients with small or abnormal proximal femoral anatomy. We performed 144 primary THAs in 114 patients using this prosthesis. Mean follow-up was 4.5 ± 3.4years (range, 1-13years). Common reasons for implantation were hip dysplasia (52%) and osteoarthritis in patients with small femoral proportions (22%). Analysis of outcomes included assessment of stem subsidence and stability. Survival was 98.6% in aseptic cases; revision-free survival was 97.9%. Femoral subsidence occurred in 84 cases (58%). No subsidence progressed after 3months. Of those that subsided, the mean distance was 2.8 ± 2.0mm. There was less subsidence in stems that stabilized prior to sixweeks (2.2 ± 1.4mm) compared to those that continued until 12weeks (3.9 ± 1.6, p = 0.02). Harris Hip, UCLA, and WOMAC scores significantly improved from pre-operative evaluation (p < 0.001*, p < 0.003*, p ≪ 0.001*); there was no difference in outcome between patients with and without subsidence (p = 0.430, p = 0.228, p = 0.147). The modified Wagner Cone demonstrates excellent clinical outcomes in patients with challenging proximal femoral anatomy. Subsidence is minor, stops by 3months, and does not compromise clinical outcome.

Coxa valga and antetorta increases differences among different femoral version measurements : potential implications for derotational femoral osteotomy planning.

To evaluate how abnormal proximal femoral anatomy affects different femoral version measurements in young patients with hip pain. First, femoral version was measured in 50 hips of symptomatic consecutively selected patients with hip pain (mean age 20 years (SD 6), 60% (n = 25) females) on preoperative CT scans using different measurement methods: Lee et al, Reikerås et al, Tomczak et al, and Murphy et al. Neck-shaft angle (NSA) and α angle were measured on coronal and radial CT images. Second, CT scans from three patients with femoral retroversion, normal femoral version, and anteversion were used to create 3D femur models, which were manipulated to generate models with different NSAs and different cam lesions, resulting in eight models per patient. Femoral version measurements were repeated on manipulated femora. Comparing the different measurement methods for femoral version resulted in a maximum mean difference of 18° (95% CI 16 to 20) between the most proximal (Lee et al) and most distal (Murphy et al) methods. Higher differences in proximal and distal femoral version measurement techniques were seen in femora with greater femoral version (r > 0.46; p < 0.001) and greater NSA (r > 0.37; p = 0.008) between all measurement methods. In the parametric 3D manipulation analysis, differences in femoral version increased 11° and 9° in patients with high and normal femoral version, respectively, with increasing NSA (110° to 150°). Measurement of femoral version angles differ depending on the method used to almost 20°, which is in the range of the aimed surgical correction in derotational femoral osteotomy and thus can be considered clinically relevant. Differences between proximal and distal measurement methods further increase by increasing femoral version and NSA. Measurement methods that take the entire proximal femur into account by using distal landmarks may produce more sensitive measurements of these differences.Cite this article: Bone Jt Open2022;3(10):759-766.

Radiological evaluation of the relationship between femoral head rotation center and trochanter major

Purpose: We aimed to investigate the distance between the tip of Trochanter Major (TTM) and the Femoral Head Rotation Center (FHC) and investigate other measurements on orthoroentgenograms obtained in the local population. Materials and methods: Patients aged 18 and over who were admitted to the hospital between 2 June 2020 and December 2020 and had an orthoroentgenogram were included in the study. Patients with hip joint degeneration, deformities, bone dysplasia, bone tumors, bone tissue irregularities, old fractures or surgical findings, and those with lower extremity length discrepancies were excluded from the study. The tip of trochanter major - The femoral head rotation center (TMFH) distance, collodiaphyseal angle, femur length, and femoral head area were measured on the orthoroentgenogram. Radiological measurements were made by two orthopedic specialists who participated in the study. In addition, the age and gender of the patients and the side of the femur evaluated were recorded. Results: When evaluated according to gender, it was observed that the femoral length of the males was approximately 35.37 ± 5.6+3 mm longer than that of the females, and the femoral head area was 3 ± 1.4 cm2 larger compared to the females (Table 1). These differences between the genders were considered statistically significant (&lt;0.001). The mean collodiaphyseal (CD) angle of 180 femurs included in the study was 131.9o ± 5.2o,the TMFH distance was measured as 4.77 ± 5.0 mm, the tip of trochanter major was above the femoral head rotation center. There was no statistically significant difference in this distance in terms of gender and mean right/left side measurements. Conclusions: The relationship between the femoral head rotation center (FHC) and the tip of the trochanter major (TTM) is a viable method in determining the lower extremity length. While evaluating this relationship, the values of the nonaffected contralateral hip can be used. However, if any deformity in the contralateral hip occurs, measurements obtained in the local population could be helpful in providing information about appropriate leg length. Keywords: Hip reconstruction, anthropometry, proximal femoral anatomy, femoral head rotation center, trochanter major ________________________________________________________________

AAHKS Best Podium Presentation Research Award: Femoral Perforation During Direct Anterior Approach Total Hip Arthroplasty: Incidence, Cohort Characteristics, and Management

BackgroundCortical perforation during femoral preparation is a recognized complication of total hip arthroplasty (THA) but the incidence, patient characteristics, management, and outcome have not been described for the direct anterior approach (DAA). MethodsA database query of all primary and conversion DAA THAs performed by a single surgeon from 2009 to 2021 was used to identify hips that sustained a recognized intraoperative femoral perforation. Radiographs were used to assess stem subsidence, Dorr femur type, and Canal Flare Index. ResultsAmong 3,973 THAs, 16 patients (0.4%) sustained perforations during broaching including 8 males and 8 females with a mean age at surgery of 65.6 (range 41-81) years and a mean body mass index of 31.0 (range 19.0-44.4). Two hips were converted to longer primary cementless stems to bypass the perforation. For the remaining 14, the broach was redirected and the same primary stem was implanted. Limited weight-bearing (6 patients) or protected weight-bearing as tolerated with a walker/cane (10 patients) was advised postoperatively. At a mean follow-up of 18.7 (range 4-105) months, all stems were stable with no fractures, subsidence, or revisions. Factors associated with perforation included difficulty with exposure (body mass index >40 or a contracture), measurable osteoporosis (Canal Flare Index <3.0), and abnormal proximal femoral anatomy due to prior trauma, retained hardware, or Perthes disease. ConclusionIn this case series, isolated perforation of an otherwise intact femur during DAA was successfully managed with redirection of the broach, implantation of a primary stem that achieved axial/rotational stability, and protected weight-bearing. Level of EvidenceIV, Case Series.

Morscher's femoral neck lengthening osteotomy through surgical hip dislocation approach for preservation of Perthes and Perthes-like deformities.

Background:Typical sequelae of Perthes disease and Perthes-like deformities comprise a short femoral neck, aspherical femoral head, and greater trochanteric overgrowth. Morscher’s osteotomy aims at restoring the normal extra-articular anatomy, but incapable of restoring a normal head-neck contour with residual impingement. Femoral neck lengthening osteotomy combined with osteochondroplasty through surgical hip dislocation approach was not previously described in the literature. We hypothesized that this technique is capable of near-normal restoration of the proximal femoral anatomy, increasing limb length, restoring abductor power, and simultaneous management of intra-articular chondro-labral disease.Methods:A prospective series of 21 consecutive patients with sequelae of Perthes disease and Perthes-like deformity (Stulberg II and III) were treated by Morscher’s osteotomy through surgical hip dislocation approach. The mean age was 14.9 years (9–30 years) and the mean follow-up was 4.5 years (2–8 years).Results:The mean Harris hip score improved significantly from 66.5 to 89.5 points (p < 0.001), and the mean limb length discrepancy improved from 2.5 to 0.6 cm (p < 0.001). The mean alpha angle improved from 81.8° to 49.5°, the mean neck-shaft angle increased from 117.8° to 129.8°, and the articulo-trochanteric distance has improved from −6.7 to 20.8 mm. Six out of 21 patients required staged periacetabular osteotomy for residual acetabular dysplasia. No cases of chondrolysis or osteonecrosis were identified.Conclusion:Femoral neck lengthening osteotomy through surgical hip dislocation appraoch has proven to be safe and effective for preservation of symptomatic hips with Perthes and Perthes-like deformities and mild to moderate femoral head deformities (Stulberg II and III). A staged periacetabular osteotomy may be required in those patients with significant acetabular dysplasia.Level of evidence:Level IV.

Среднесрочные результаты внесуставной корригирующей остеотомии бедра при юношеском эпифизеолизе головки бедренной кости

Despite the diversity of surgical options for slipped capital femoral epiphysis (SCFE), there is an ongoing search for the technique that would ensure a satisfactory outcome, stable fixation of bone fragments and a low rate of complications. The aim of this study was to improve the surgical technique for SCFE in patients with moderate and severe SCFE. The study included 52 children (16 girls and 36 boys) aged 10-15 years (the mean age was 13.2 years) with chronic severe (Krechmar’s stage III) stable (according to Loder’s classification) SCFE. The control group (n = 16) underwent a classic Imhauser procedure; the main group (n = 36) underwent a triplane osteotomy proposed by the authors of the study. The patients were examined prior to surgery and in the late follow-up period (the mean follow-up time was 4.7 years, ranging from 1 to 10 years). The procedure included a clinical examination, history taking, radiography to measure the slip angle and the severity of the slip, and the Harris hip score to assess hip function. After 4.7 years, both groups demonstrated an increase in the range of motion, in comparison with their preoperative results (p ≤ 0.05), good Harris hip scores (94 points in the main group and 81 points in the control group. Postoperative radiographs showed consolidation of the bone, recovery of the proximal femur anatomy. Leg length discrepancy improved significantly in both groups. The proposed technique for extraarticular osteotomy allows recovering the length of the affected leg, the anatomy and physiology of the hip joint, is simple and less traumatic.

Femoral neck shaft angle is not correlated with femoral version: A retrospective study of computed tomography scans

BackgroundAn understanding of femoral anteversion and neck-shaft angle (NSA) is essential to deliver optimal orthopaedic surgical care. Despite the importance, there is little research examining the relationship between femoral anteversion and the NSA in an adult population. This study sought to determine if there is a correlation between femoral neck shaft angle and version in skeletally mature adults using computed tomography (CT) scanograms. MethodsBetween January 2010 and June 2017, all skeletally mature patients who had received a CT scanogram of the lower extremity were reviewed. Exclusion criteria included: (1) radiographic evidence of osteoarthritis, (2) history of hip, femur, or knee surgery or trauma, (3) and anatomic abnormalities of the proximal femur including prior slipped capital femoral epiphysis or Legg-Calvé-Perthes disease. Both femoral version and NSA were measured by a musculoskeletal fellowship trained radiologist using CT scanograms. Correlation between femoral version and NSA was determined using coefficient of determination (R2) and Pearson correlation coefficient (r) for the group as a whole and for each sex. ResultsThere was no statistical correlation between femoral version and NSA for either the entire cohort or for each sex. For the entire cohort, R2 = 0.0016 and r was 0.04 (p=0.45), for females, R2 = 0.0005 and r was 0.0224 (p=0.72), and for males, R2 = 0.0342 and r was 0.185 (p=0.07). ConclusionThere was no correlation between femoral version and NSA. This finding is beneficial for surgeons to understand the proximal femoral anatomy. Patients with an increased femoral NSA should not be assumed to have increased femoral anteversion. Level of EvidenceLevel III, Retrospective Cohort Study

A study of femoral offset in the South Indian population and its clinical implications in hip arthroplasty

BackgroundRecreation of the normal proximal femoral anatomy is paramount for a successful total hip arthroplasty. The study aims to look at whether the range of offset options available in the femoral stems available locally, would be adequate to restore the native femoral horizontal offset (FHO) of the South Indian population. MethodThis is a prospective single-center study of 1-year duration, where we study the FHO on radiographs and CT scans in 100 patients. We then look at the femoral stems available in the Indian market and see if the offset may be restored with the available stems. ResultThe FHO ranged from 23.3 to 46.9 mm with a mean of 35.7 ± 5.3 mm. The females in the group (33.86 ± 4.71 mm) had a lower FHO compared to males (37.78 ± 5. 21 mm). We found that 50% of the South Indian population and 62% of the females have an offset less than 35 mm. Among the 18 stems that we studied, four out of nine cemented and two out of nine uncemented stems did not offer an offset below 35 mm. ConclusionThe native FHO in the South Indian population is significantly less than that of Caucasians. The surgeon should be aware that many implant systems available in India do not offer offset options in this range. In this group, even when a stem with smallest offset is used, there is a risk of increasing the FHO with a potential for intraoperative fractures due to difficult reduction and leg-lengthening. Hence, the surgeon should template carefully and choose only those implant systems which can offer an offset similar to the native offset to restore the anatomy accurately. We recommend that all manufacturers consider offering implants with smaller offset (25–35 mm).

Sensitivity of the stress field of the proximal femur predicted by CT-based FE analysis to modeling uncertainties.

Proximal femur anatomy and bone mineral density vary widely among individuals, precluding the use of one predefined finite element (FE) model to determine the stress field for all proximal femurs. This variability poses a challenge in current prosthetic hip design approach. Given the numerous options for generating computed tomography (CT)-based FE models, selecting the best methods for defining the mechanical behavior of the proximal femur is difficult. In this study, a combination of computational and experimental approaches was used to explore the susceptibility of the predicted stress field of the proximal femur to different combinations of density-elasticity relationships, element type, element size, and calibration error. Our results suggest that FE models with first-order voxelized elements generated by the Keyak and Falkinstein density-elasticity relationship or quadratic tetrahedral elements generated by the Morgan density-elasticity relationship lead to accurate estimations of the mechanical behavior of human femurs. Other combinations of element size, element type, and mathematical relationships produce less accurate results, especially in the cortical bone of the femoral neck and calcar region. The voxelized model was more susceptible to variation of element size and density-elasticity relationships than FE models with quadratic tetrahedral elements. Regardless of element type, the stress fields predicted by the Keyak and Falkinstein and the Morgan relationships were the most robust to calibration error when deriving material density from CT-generated Hounsfield data. These results provide insight into the implementation of a robust platform for designing patient-specific implants capable of maintaining or modifying the stress in bones.

Radiographic Assessment of the Proximal Femoral Anatomy in An Indigenous African Adult Population

Background: Hip surgeries such as fracture fixation, corrective osteotomy, hemiarthroplasty, or total hip arthroplasty require accurate preoperative templating for a successful outcome. Such templating is done using the proximal femur and the acetabulum radiographs, depending on the planned surgery. Understanding the normal radiographic anatomy of the proximal femur is crucial to differentiate a normal from pathological anatomy. Proximal femoral anatomic indices include the femoral head diameter, femoral neck diameter, femoral neck length, femoral offset, femoral neck axis length and the femoral neck-shaft angle. Aim: This study assesses and establishes the average values of the proximal femoral anatomy in an indigenous African adult population. Method: This cross-sectional study examined 190 normal anteroposterior (AP) radiographs of the pelvis. The mean age, weight and height of the subjects were obtained. The following proximal femoral anatomic parameters were measured: femoral neck length (FNL), femoral neck diameter (FND), femoral head diameter (FHD), femoral neck-shaft angle (FNSA), femoral offset (FO) and femoral neck axis length (FNAL). The authors compared the mean difference of the parameters between the genders and the age categories and assessed the parameter correlations with the patients’ weight and height. Results: Males constituted 63 (33.2%) of the study population. The mean age of the subjects was 51.46 years (SD = 16.37). The mean weight was 76.13 kg, while the mean height was 1.62 m. The mean values of the proximal femoral parameters were as follows: FNL 4.52cm, FND 3.42cm, FHD 4.76cm, FNSA 132.960, FO 4.09cm, and FNAL 10.34cm. Males have a significantly higher mean value in all the parameters except the FO. None of the parameters showed any significant difference among the age categories except the FNL. A post-hoc analysis showed that the difference in the FNL lies between the young and the elderly age groups. The subjects’ height correlated with all the parameters except FNSA, while the weight correlated with the FND, FNSA and FNAL. Conclusion: The proximal femoral anatomy in Africans differed from those published in foreign literature. This knowledge is crucial for implant manufacturing companies and preoperative templating for hip surgeries. KEY WORDS: Proximal femur, Anatomy, Black population.

Radiographic analysis of the proximal femoral anatomy in the Croatian population

PurposeThe goal of total hip endoprosthesis is to achieve painless and functional hip for long term. Accurate reconstruction of hip anatomy largely depends on the implant design. In order to select an implant in correspondence with the native hip, the proximal femoral morphology has been in focus of many studies in the past years. The purpose of this study is to analyze proximal femoral geometry in the Croatian population by radiographic evaluation.MethodsWe conducted a retrospective study analyzing conventional radiographies of the hip, obtained within the last four years from the database of Clinic for Orthopaedic Surgery Lovran. The number of studied patients was 300,168 women and 132 men. The proximal femoral geometric parameters assessed were as follows: femoral head diameter, femoral neck length, neck-shaft angle, angle of femoral neck anteversion, and lateral femoral offset. The results obtained were compared between genders and with results of other studies.ResultsProximal femoral anatomy differed in femoral head diameter and lateral femoral offset between males and females in our group of patients, while femoral neck length, femoral neck shaft angle, and femoral neck anteversion have shown similar values in both genders. Our study also showed specificity of the Croatian population in almost all parameters of proximal femoral anatomy, in comparison with other ethnic groups.ConclusionOur results support the observation on high diversity in the morphology of the proximal femur and the specificity of the proximal femoral anatomy of the Croatian population.

Outcome of the modified Dunn procedure in severe slipped capital femoral epiphysis

BackgroundThe modified Dunn procedure has rapidly gained popularity as a treatment for slipped capital femoral epiphysis (SCFE) during the past few years. However, there is limited information regarding its safety and efficacy in severe slips with this procedure. The purpose of this study is to present clinical results and incidence of complications associated with the modified Dunn osteotomy in a consecutive series of severe SCFE cohort.Patients and methodsWe retrospectively assessed the outcomes of all twenty patients who had been treated with the modified Dunn procedure in our tertiary-care institution. According to the Loder and Fahey criteria, all cases were classified as severe slips; nineteen cases were stable, and one case was an unstable slip. All surgical procedures were performed by one senior orthopedic surgeon who had specific training in the modified Dunn procedure. Operative reports, outpatient records, follow-up radiographs, and the intraoperative findings were reviewed to determine the demographic information, type of fixation, final slip angle, presence of avascular necrosis (AVN), and any additional complications. The mean age of the patients was 13.2 ± 1.6 years (range, 10 to 17 years). Twenty patients (twenty-one hips) with a mean of 31.2 ± 14 months (range, 12 to 57 months) follow-up met the inclusion criteria. Pain and function were assessed by the modified Harris score and WOMAC score. Radiographic anatomy was measured using the slip angle and α-angle. The radiographic findings related to the anatomy of the femoral head-neck junction, as well as signs of early-onset of osteoarthritis (OA) and AVN, were evaluated pre- and postoperatively.ResultsOverall, nineteen patients had excellent clinical and radiographic outcomes with respect to hip function and radiographic parameters. One patient (5%) who developed implant failure at 3 months postoperatively had a poor outcome. The mean preoperative slip angle was corrected from 63.2 ± 8.1° (range, 51 to 84°) to a normal value of 7.5 ± 3.5° (range, 2 to 15°) (p < 0.01). The mean α-angle was improved from an average of 94.5 ± 21.1° (range, 61 to 123°) to postoperative 42 ± 6.4° (range, 25 to 55°) (p < 0.01). The mean modified Harris hip and WOMAC scores postoperatively were 96.7 ± 13.4 (range, 40 to 100) and 95.4 ± 10.6 (range, 38 to 100), respectively. There were no cases of the development of femoroacetabular impingement (FAI) and the progression of OA. We did not record any case of AVN, closure of the growth plate, heterotopic ossification (HO), trochanteric nonunion, or limb length discrepancy that occurred postoperatively either at the most recent follow-up.ConclusionsOur series of severe SCFEs treated with the modified Dunn osteotomy demonstrated that the procedure is safe and capable of restoring more normal proximal femoral anatomy by maximum correction of the slip angle, minimizing probability of secondary FAI and early onset of OA. However, despite its lower surgical complication rate compared with alternative treatment described in the literature for SCFE, AVN can and do occur postoperatively which should always be concerned in every hip.

Arthroscopic Femoral Osteochondroplasty for Cam-type Femoroacetabular Impingement: Cortical–Cancellous Sclerotic Boundary Guides Resection Depth

Hip arthroscopy and femoral osteochondroplasty are commonly used in the treatment of femoroacetabular impingement (FAI). Determining the correct resection depth of the femoral head–neck cam lesion intraoperatively can be challenging. Both inadequate resection and over-resection may result in complications, underlying the importance of using a consistent and accurate technique when resecting and reshaping the proximal femur. Osseous resection to a depth of the subchondral cortical–cancellous bone margin in individuals with FAI has been shown to restore proximal femoral anatomy to within submillimeter differences when compared with control subjects without FAI. This bony boundary may be used as an intraoperative guide to consistently achieve appropriate resection depth. The sclerotic margin indicating the extent of the cam-type deformity can be evaluated with preoperative radiographs and recreated fluoroscopically, giving the surgeon a reliable intraoperative template. In addition, changes in clinical appearance during arthroscopy, particularly identification of the underlying trabecular structure at the cortical–cancellous border during resection, provides a visible, reliable intraoperative guide to resection depth.

Morphology of the Greater Trochanter: An Assessment of Anatomic Variation and Canal Overhang

BackgroundVarus malposition is a risk of early failure in total hip arthroplasty. The degree to which the tip of the greater trochanter (GT) overhangs the canal can increase this risk. Although we know proximal femoral anatomy is variable, no study has addressed variations in medial overhang of the GT on plain radiographs. MethodsAll low anteroposterior pelvis radiographs more than 1 year were reviewed 3 times by 2 orthopaedic surgeons and one radiologist. The canal width (CW) was measured 10 cm below the lesser trochanter. Canal overhang (CO) was defined by the distance between the lateral medullary canal and a parallel line beginning at the most medial aspect of the GT. The overhang index (OI) is defined as the percentage of the canal overhung by the GT. ResultsThe mean CW was 13.5 mm, mean CO 16.4 mm, and mean OI 1.22. Hips were then classified as the following: (A) OI < 0.5 (n = 8), (B) OI 0.5-1.0 (n = 78), (C) OI 1.0-1.5 (n = 191), and (D) OI > 1.5 (n = 68). Intraobserver reliability was excellent for all measures: 0.89 (confidence interval: 0.87-0.91) for CW, 0.96 (0.95-0.97) for CO, and 0.97 (0.97-0.98) for OI. Interobserver reliability was good for CW 0.75 (0.70-0.79) and excellent for CO 0.90 (0.88-0.92) and OI 0.95 (0.94-0.96). ConclusionsVariations in the morphology of the proximal femur can predispose to varus component malposition. The degree to which the GT overhangs the canal can be quantified and classified based on plain films. This can aid in preoperative planning and help guide intraoperative proximal femoral preparation.