Femoral Component Research Articles

Safety of using a large femoral head on thin polyethylene for total hip arthroplasty based on different types of polyethylene

The use of a large femoral head in total hip arthroplasty (THA) to stabilize and reduce the incidence of dislocation is on the increase, but concerns arise when combining them with small acetabular components due to potential mechanical failures in thin polyethylene (PE) liners. A single-institution, retrospective cohort study was conducted on 116 patients with minimum 2-year follow-up who received 36-mm femoral heads and acetabular components ≤ 52 mm, using either remelted highly cross-linked polyethylene (remelted HXLPE) or vitamin E-infused HXLPE (VEPE). Osteolysis and implant loosening were not observed in either group. Although a fracture of the PE liner was observed in each group (1.7%), the clinical outcomes were excellent, as the mean modified Harris Hip Score (mHHS) at the last follow-up was 93.5. Moreover, the mean linear wear rates measured by digital imaging software in both groups were low, with 0.035 mm/y in remelted HXLPE and 0.030 mm/y in VEPE. In conclusion, The use of a large femoral head on a thin PE liner can be a viable treatment option in patients who need to prioritize stability; however, careful attention should be paid to mechanical fractures of the PE liner.

Computed tomography-based patient-specific cutting guides used for positioning of the femoral component of implants during unicompartmental knee arthroplasty: a cadaver study

BackgroundTo investigate whether patient-specific instrumentation (PSI) improves the femoral component positioning of implants during unicompartmental knee arthroplasty (UKA) using cadaver bone models.MethodsFifty adult cadaveric femoral bone specimens collected from February 2016–2018, were randomized to receive medial UKA with a PSI guide (n = 25) or conventional instrumentation (CI) (n = 25). Standard anteroposterior and lateral view radiographs were obtained postoperatively to assess the coronal and sagittal positioning of the femoral prostheses, respectively. The osteotomy time was recorded to assess the convenience of PSI in guiding osteotomy.ResultsOsteotomy time significantly shortened in the PSI group (3.12 ± 0.65 versus 4.33 ± 0.73 min, p < 0.001). There was a significant difference in the postoperative coronal alignment of the femoral component between the PSI and CI groups (varus/valgus angle: 1.43 ± 0.93° vs. 2.65 ± 1.50°, p = 0.001). The prevalence of outliers in coronal alignment was lower in the PSI than the CI group (2/25, 8% vs. 9/25, 36%). Sagittal posterior slope angle of the femoral component was significantly different between the two groups (8.80 ± 0.65° and 6.29 ± 1.88° in the CI and PSI groups, respectively, p < 0.001). The malalignment rate of the femoral component in the sagittal plane was 60% in the CI group, whereas no positioning deviation was observed in the PSI group.ConclusionThis study used a cadaver model to support the fact that CT-based PSI shows an advantage over CI in optimizing implant positioning for UKAs.

Influence of the modified Dunn procedure on the spine–pelvis relationship in children with severe slipped capital femoral epiphysis

BACKGROUND: Slipped capital femoral epiphysis (SCFE) is one of the most severe hip joint diseases in children. It is characterized by the development of unilateral or bilateral deformity of the proximal femoral epimetaphysis of varying degrees. The pronounced deformity of the femoral component of the affected joint leads to pelvic retroversion, decreased lumbar lordosis, increased thoracic kyphosis (TK), and formation of type I (hypolordotic) vertical posture according to the Roussouly classification, contributing to degenerative and dystrophic processes in the lumbosacral spine. At present, no data in the literature present the effect of surgical treatment on frontal and sagittal spine–pelvis relationships in the patients examined.&#x0D; AIM:To performacomparative radiological evaluation of the sagittal spine–pelvis relationship in children with severe SCFE before and after the modified Dunn procedure.&#x0D; MATERIALS AND METHODS:The study included 30 patients (30 hip joints) aged 14–18 years with severe SCFE characterized byaposterior epiphysis displacement of 60° and downward of no more than 10° in one of the joints and no displacement (preslip stage) in the other. All children underwent the modified Dunn procedure on one side and fixation of the epiphysis of the femoral head withacannulated screw on the other side. Before and after surgery, the patients underwent clinical and radiologic examinations. Standing radiographs were used to evaluate lumbar lordosis, TK, pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS), and sagittal vertical axis (SVA). The obtained data were analyzed statistically.&#x0D; RESULTS:At the examination 3–3.5 years after the abovementioned interventions,apronounced increase was noted in the mean PI value, which began to correspond to type III (harmonious) of upright posture according to the Roussouly classification.Achange was noted in the mean values of positional indices PT (decreased) and SS (increased), and pelvic retroversion disappeared. The mean global lumbar lordosis (GLL) and lumbar lordosis increased, which led toadecrease in TK and the mean value of TK. All clinical observations showedasignificant decrease in the mean global sagittal balance index (the sagittal vertical axis (SVA)) and absence of torso imbalance.&#x0D; CONCLUSIONS:After performing the modified Dunn procedure on the one side and fixation of the epiphysis of the femoral head withascrew on the other side, children with severe SCFE demonstrated improvements in all the studied indices of sagittal spine–pelvis ratios. Consequently, the type of vertical posture according to the Roussouly classification changes from type I (hypolordotic) to type III (harmonious), and the probability of degenerative and dystrophic process development in the lumbosacral spine decreases.

Accuracy and reproducibility of two-dimensional computed tomography-based positioning of femoral component rotational alignment in preoperative planning for total knee arthroplasty

BackgroundPoor rotation of the femoral component in total knee arthroplasty (TKA) can result in various postoperative complications, underscoring the critical importance of preoperative planning.PurposeTo improve the accuracy of femoral component positioning during TKA, this study compared the accuracy and repeatability of different two-dimensional (2D) computed tomography (CT) measurement methods for measuring the posterior condylar angle (PCA) in preoperative TKA planning.MethodsA retrospective analysis was conducted on 75 patients (150 knees) who underwent bilateral lower extremity computed tomography angiography (CTA) at Fuyang People's Hospital from January 2021 to July 2021. Three different methods were used to measure the PCA based on 2D CT images (axial CT slices) and three-dimensional(3D) models (femoral models reconstructed from CT data) in this study. Method 1: Single-plane 2D CT measurement, measuring PCA in the most obvious single-plane CT slice of the surgical transepicondylar axis (sTEA); Method 2: multi-plane 2D CT measurement, identifying and locating anatomical landmarks in multiple 2D CT slices and measuring PCA; Method 3: 3D model measurement, measuring PCA in the reconstructed femur 3D model. Compare the differences in PCA measurements between the three measurement methods. A positive PCA measurement was recorded when the sTEA was externally rotated relative to the posterior condylar line (PCL). Any difference exceeding 3° between the PCA measurement in the 2D CT and the PCA reference value in the 3D model was classified as an outlier. The intraclass correlation coefficient (ICC) and Bland–Altman method were utilized to assess the intra- and inter-observer reproducibility of the three measurement methods.ResultsThe PCA measurement in the single-plane 2D CT was 1.91 ± 1.94°, with a measurement error of − 1.22 ± 1.32° and 12.7% of outlier values. In the multi-plane 2D CT, the PCA measurement was 2.96 ± 1.68°, with a measurement error of -0.15 ± 0.91° and 6.0% of outlier values. The PCA measurement in the 3D model was 3.12 ± 1.69°. The PCA measurement in single-plane 2D CT was notably smaller than that in multi-plane 2D CT and 3D models, with no significant difference between the latter two. The multi-plane 2D CT showed significantly lower measurement error and outlier values than the single-plane 2D CT. All three PCA measurement methods exhibited high reproducibility (ICC: 0.93 ~ 0.97).ConclusionsUsing of multi-plane 2D CT for measuring PCA in preoperative planning of TKA has high reproducibility and accuracy, with fewer outlier values. We recommend preoperative measurement of PCA using muti-plane 2D CT to improve the accuracy of positioning the femoral component rotational alignment during surgery.

Development and Validation of an Artificial Intelligence Preoperative Planning and Patient-Specific Instrumentation System for Total Knee Arthroplasty.

Accurate preoperative planning for total knee arthroplasty (TKA) is crucial. Computed tomography (CT)-based preoperative planning offers more comprehensive information and can also be used to design patient-specific instrumentation (PSI), but it requires well-reconstructed and segmented images, and the process is complex and time-consuming. This study aimed to develop an artificial intelligence (AI) preoperative planning and PSI system for TKA and to validate its time savings and accuracy in clinical applications. The 3D-UNet and modified HRNet neural network structures were used to develop the AI preoperative planning and PSI system (AIJOINT). Forty-two patients who were scheduled for TKA underwent both AI and manual CT processing and planning for component sizing, 20 of whom had their PSIs designed and applied intraoperatively. The time consumed and the size and orientation of the postoperative component were recorded. The Dice similarity coefficient (DSC) and loss function indicated excellent performance of the neural network structure in CT image segmentation. AIJOINT was faster than conventional methods for CT segmentation (3.74 ± 0.82 vs. 128.88 ± 17.31 min, p < 0.05) and PSI design (35.10 ± 3.98 vs. 159.52 ± 17.14 min, p < 0.05) without increasing the time for size planning. The accuracy of AIJOINT in planning the size of both femoral and tibial components was 92.9%, while the accuracy of the conventional method in planning the size of the femoral and tibial components was 42.9% and 47.6%, respectively (p < 0.05). In addition, AI-based PSI improved the accuracy of the hip-knee-ankle angle and reduced postoperative blood loss (p < 0.05). AIJOINT significantly reduces the time needed for CT processing and PSI design without increasing the time for size planning, accurately predicts the component size, and improves the accuracy of lower limb alignment in TKA patients, providing a meaningful supplement to the application of AI in orthopaedics.

A Radiographic Evaluation of Uncemented Total Hip Replacements and the Role of Uncemented Implants in the Management of Hip Osteoarthritis in the Elderly Population.

Introduction The idea of an uncemented, fully coated hydroxyapatite (HA) stem was introduced almost 40 years ago, aiming to achieve a solid biological fixation by preserving natural bone activity. While many studies underline the longevity of uncemented total hip replacement (THR), NHS England's Best Practice Tariff (BPT) recommends using cemented implants in patients over the age of 69, with financial penalties when this policy is not met. At the same time, the 'paradox' of increased use of uncemented implants worldwide has been well described, with many surgeons using them regardless of the age group of the patient. Materials and methods This study focuses on the radiographic evaluation of the uncemented Pinnacle/Corail total hip replacement construct in 123 patients of all age groups who underwent an elective procedure, with a minimum radiographic follow-up of two years. Implant information (collared or non-collared stem), femur type (Dorr classification), age, gender, and revision rate were collected and radiographic analysis of the femoral stem and acetabular component was performed for the immediate post-operative, six-month, one- to two-year follow-up radiograph of all patients. We conducted a statistical analysis, dividing the patients into two groups based on age: those above or below 69 years old. Results There was no statistically significant difference in rates of radiographic lucency after two years with regard to the femoral component. Both collared and non-collared stems seem to perform equally well, with no significant difference detected. However, a statistically significant difference in rates of radiographic lucency of the acetabular cup was noted between the two age groups (p=0.018), with higher rates detected in the under-69-year-old age group. Conclusion This study demonstrates that, radiographically, the uncemented Pinnacle/Corail construct performs equally well in all age groups. In our cohort of patients, the age of the patient did not predict the osseointegration of the implant in the short-term follow-up.

Variations in Trochlear Morphology of Contemporary and Legacy Total Knee Arthroplasty Prostheses: A Review of 22 Designs

BackgroundThe morphology of the trochlear compartment of total knee arthroplasty (TKA) prostheses is a major determinant of postoperative patello-femoral kinematics, particularly with unresurfaced patellae. The objective of this study was to quantify and compare the trochlear morphology of a large series of contemporary and legacy TKA designs. MethodsThe 3-dimensional surface models of 22 femoral components (13 contemporary and 9 legacy) were created using high-resolution laser scanning. The trochlear profile of each component was analyzed from proximal to distal in 15° increments around the trochlear axis. In each profile, the following variables were measured: sulcus angle, medio-lateral deviation of the sulcus, the height and width of the facets, and the trochlear groove orientation. ResultsIn the contemporary group, the sulcus angle decreased progressively along the trochlear arc to varying degrees, except for 2 symmetrical designs, whereas the sulcus angle of the legacy designs showed considerable variability. The height of the medial facet was very strongly correlated with that of the lateral facet in the contemporary group (R2 = 0.89), whereas the correlation was weak for the legacy designs (R2 = 0.36). Moreover, the trochlear sulcus deviated laterally from distal to proximal in 10 contemporary designs and 7 legacy designs, resulting in a trochlear groove orientation of 4.2 to 11.1° and 4.3 to 10.5°, respectively. In the remaining 5 designs (3 contemporary and 2 legacy), the sulcus was vertical. ConclusionsThere is more consistency in trochlear morphology of contemporary TKA designs compared to that of legacy designs, yet there are still large variations between different designs.

Early outcomes of total hip arthroplasty using point-of-care manufactured patient-specific instruments: a single university hospital’s initial experience

BackgroundThe use of 3D-printed Patient-Specific Instruments (PSI) has been investigated to enhance the postoperative functional results in total hip arthroplasty (THA) and has been recognized as an innovative approach for the optimal alignment of hip implant components. Point-of-care production is gradually becoming the norm for PSI manufacturing. The purpose of this article is to assess the accuracy and safety of PSI for total hip arthroplasty performed at the point-of-care in Vietnam.Methods34 THA cases were assessed in this prospective study. A template for the size and orientation of the implant and the design of the PSI was generated using data from preoperative 3D computed tomography (CT) scanning of the lower limb. The principal surgeon determined the implants’ position and PSI design directly using the software. The PSI is then produced using a 3D-compatible resin printer in our manufacturing hospital. The PSI, consisting of an acetabulum and a femoral component placed press-fit on the bony surface, guided surgeons to precisely ream the acetabulum and cut the femoral neck according to the pre-planned plane. Postoperative CT scanning was obtained and superimposed onto the 3D model of the implant to evaluate the accuracy of the procedure by comparing the orientation values of the cup and the alignment of the stem between the planned and the actual results. Intra- and postoperative clinical parameters of surgery, including surgical time, intra-operative blood loss, complications, and the first ambulation, were also recorded to evaluate the safety of the surgery.ResultsThe preparation for PSI required an average of 3 days. 94% of cup size and 91% of stem size were correctly selected. The mean values of postoperative inclination and anteversion were 44.2° ± 4.1° and 19.2° ± 5.6°, respectively. 64.7% of cases deviated from planned within the ± 50 range and 94.1% within the ± 10° range. There was no significant statistical difference between the planned and the achieved values of stem anteversion, osteotomy height, and leg length discrepancy (p > 0.05). The average surgical time was 82.5° ± 10.8 min, and the intraoperative blood loss was estimated at 317.7° ± 57.6 ml. 64.7% of patients could walk on the day of surgery. There were no complications reported.ConclusionsThe point-of-care manufactured PSI is a useful solution for improving the accuracy of total hip arthroplasty surgery, especially in restoring implant orientation and reducing leg length discrepancy. However, long-term clinical follow-up evaluation is needed to confirm the efficacy and safety of this approach.

Repercusión de la alineación mecánica en el tiempo de supervivencia de prótesis total de rodilla primaria.

Introduction: Currently, there is no consensus among authors on how radiological alignment influences the survival of the primary total knee prosthesis implant. Methods: Retrospective study analyzing radiological measurements in the coronal and sagittal plane in patients who underwent primary total knee arthroplasty in our center who required revision surgery. Results: The percentage of cases within the correct angle range in the femoral component were 93.9% coronal, 69% sagittal, and in the tibial component 81.6% coronal, 85.7% sagittal. The mean mechanical alignment of the limb was 179º. Conclusion: Although there is a trend for the time interval between prosthesis implantation and revision surgery to be longer if these angles are within the range, mechanical alignment does not seem to influence survival time in our sample.

Deep-Learning Automation of Preoperative Radiographic Parameters Associated With Early Periprosthetic Femur Fracture After Total Hip Arthroplasty

BackgroundThe radiographic assessment of bone morphology impacts implant selection and fixation type in total hip arthroplasty (THA) and is important to minimize the risk of periprosthetic femur fracture (PFF). We utilized a deep-learning algorithm to automate femoral radiographic parameters and determined which automated parameters were associated with early PFF. MethodsRadiographs from a publicly available database and from patients undergoing primary cementless THA at a high-volume institution (2016 to 2020) were obtained. A U-Net algorithm was trained to segment femoral landmarks for bone morphology parameter automation. Automated parameters were compared against that of a fellowship-trained surgeon and compared in an independent cohort of 100 patients who underwent THA (50 with early PFF and 50 controls matched by femoral component, age, sex, body mass index, and surgical approach). ResultsOn the independent cohort, the algorithm generated 1,710 unique measurements for 95 images (5% lesser trochanter identification failure) in 22 minutes. Medullary canal width, femoral cortex width, canal flare index, morphological cortical index, canal bone ratio, and canal calcar ratio had good-to-excellent correlation with surgeon measurements (Pearson’s correlation coefficient: 0.76 to 0.96). Canal calcar ratios (0.43 ± 0.08 versus 0.40 ± 0.07) and canal bone ratios (0.39 ± 0.06 versus 0.36 ± 0.06) were higher (P < .05) in the PFF cohort when comparing the automated parameters. ConclusionsDeep-learning automated parameters demonstrated differences in patients who had and did not have early PFF after cementless primary THA. This algorithm has the potential to complement and improve patient-specific PFF risk-prediction tools.

CT-based, robotic-arm assisted total hip arthroplasty (Mako) through anterior approach provides improved cup placement accuracy but no difference in clinical outcomes when compared to conventional technique

BACKGROUND: With the restoration of the natural hip biomechanics, a successful total hip arthroplasty (THA) and long-term survival is pursued. Although robotic THA (rTHA) has been developed to increase accuracy of implant positioning, leg lengths and offsets, discussions about its radiological and clinical advantages over conventional THA (cTHA) continues. OBJECTIVE: The aim of this study was to compare clinical and radiological outcomes of robotic and conventional THA. METHODS: This retrospective study compares functional and radiological outcomes of 82 rTHA with a matched group of 82 cTHA in terms of age, sex, body mass index and preoperative functional scores. The minimum follow up was 12 months for all patients. Functional outcomes were Harris Hip Score (HHS) and the Western Ontario and McMaster University Osteoarthritis index (WOMAC) evaluated pre- and postoperatively. Radiological evaluations included position of cup placement according to Lewinnek and Callanan safe zones, Canal Fill Ratio (CFR), Leg Length Discrepancy (LLD), Lateral offset (LO) and Femoral Component Alignment (FCA). Complications were also evaluated. RESULTS: In the rTHA group, 91.5% (75 out of 82) of the acetabular cups were positioned within the safe zone whereas it was 63.4% (52 out of 82) for the cTHA group (p&lt; 0.001). According to Callanan, they were 84.1% and 50%, respectively (p&lt; 0.001). Between the groups, no statistically significant difference was found in CFR, LLD, HO, FCA, AI, AA, WOMAC, HHS and major complication rates. CONCLUSION: rTHA is superior to cTHA in terms of accuracy and reproducibility of the cup placement, however no apparent clinical benefit was found in short term follow.

TOPOLOGY OPTIMIZATION AND MECHANICAL PROPERTIES STUDIES ON TOTAL KNEE REPLACEMENT (TKR) USING FINITE ELEMENT SIMULATION METHOD

This study aims to propose lower material consumption of Total Knee Replacement (TKR), by employing Topology Optimization (TO). The objective is to propose a new knee implant design via Topology Optimization. Additionally, this study aims to calculate optimum cost-effective materials for the tibial and femoral components of the knee implant while maintaining the desired mechanical properties. SolidWorks and ANSYS Workbench software are used as tools in this study. Initially, the knee implant design was created using SolidWorks, followed by analysis and topology optimization using ANSYS Workbench. The method involves comparing the mechanical properties before and after optimization and calculating the amount of material saved through the optimization process. According to the findings, optimization may result in a reduction in material consumption of up to 23.96% with a difference of less than 5% in terms of the mechanical characteristics of the original design and the newly optimized design.

Prediction of Total Knee Arthroplasty Sizes with Demographics, including Hand and Foot Sizes.

Introduction Anticipating implant sizes before total knee arthroplasty (TKA) allows the surgical team to streamline operations and prepare for potential difficulties. This study aims to determine the correlation and derive a regression model for predicting TKA sizes using patient-specific demographics without using radiographs. Methods We reviewed the demographics, including hand and foot sizes, of 1339 primary TKAs. To allow for comparison across different TKA designs, we converted the femur and tibia sizes into their anterior-posterior (AP) and medial-lateral (ML) dimensions. Stepwise multivariate regressions were performed to analyze the data. Results Regarding the femur component, the patient's foot, gender, height, hand circumference, body-mass-index, and age was the significant demographic factors in the regression analysis (R-square 0.541, p-value <0.05). For the tibia component, the significant factors in the regression analysis were the thee patient's foot size, gender, height, hand circumference, and age (R-square 0.608, p-value <0.05). The patient's foot size had the highest correlation coefficient for both femur (0.670) and tibia (0.697) implant sizes (p-value <0.05). We accurately predicted the femur component size exactly, within one and two sizes in 49.5%, 94.2%, and 99.9% of cases, respectively. Regarding the tibia, the prediction was exact, within one and two sizes in 53.0%, 96.0%, and 100% of cases, respectively. Conclusion The regression model, utilizing patient-specific characteristics, such as foot size and hand circumference, accurately predicted TKA femur and tibia sizes within one component size. This provides a more efficient alternative for preoperative planning.

The sensitivity of the stiffness and thickness of a titanium inlay in a cementless PEEK femoral component to the micromotions and bone strain energy density

Polyetheretherketone (PEEK) has been proposed as alternative material for total knee arthroplasty implants due to its low stiffness, which may reduce stress-shielding. In cementless fixation, a proper primary fixation is required for long-term fixation. Previous research showed that the lower stiffness of a cementless PEEK femoral component results in larger micromotions at the implant-bone interface compared to a cobalt-chrome femoral component. A titanium inlay on the PEEK implant surface may improve the primary fixation while maintaining the favourable stiffness properties. Therefore, the effect of thickness and stiffness of a titanium inlay on the primary fixation and stress-shielding was investigated. A finite element model of the femur and femoral component was created with five titanium inlay variants. The micromotions and strain energy density (SED) were quantified as outcome measures. The distal thin – proximal thick variant showed the largest resulting micromotions (51.2 µm). Relative to the all-PEEK femoral component, the addition of a titanium inlay reduced the micromotions with 30 % to 40 % without considerably affecting the stress-shielding capacity (strain energy difference of 6 % to 10 %). Differences in micromotions (43.0–51.2 µm) and SED between the variants were relatively small. In conclusion, the addition of a titanium inlay could lead to a reduction of the micromotions without substantially affecting the SED distribution.

Which method for femoral component sizing when performing kinematic alignment TKA? An in silico study

IntroductionThe kinematically alignment (KA) technique for TKA aims to reproduce the pre-arthritic knee anatomy, including both the femoro-tibial and femoro-patellar joints. An in silico study was conducted to compare 3 different femoral component sizing techniques to identify the anatomical landmark which allows closest restoration of the native trochlear anatomy. Our study's question was: what was the best method for sizing the femoral component when performing KA-TKA? It was hypothesized that sizing the femoral component by aiming to restore the groove height would be the best method to restore the native trochlear anatomy. MethodsGMK sphere® (Medacta) femoral component 3D models were virtually kinematically aligned on 30 tri-dimensional (3D) bony osteoarthritis knee models. The femoral component was mediolaterally positioned to match distal native and prosthetic grooves. Three methods were used to size the femoral component: a conventional method with the anterior femoral cut flush to the femoral cortex (C-KATKA) and two alternative personalized methods aiming to recreate either the medial facet's height (ATM-KATKA) or the groove's height (ATG-KATKA). In-house analysis software was used to compare native and prosthetic trochlear articular surfaces and mediolateral implant overhangs. ResultsCompared with the C-KATKA, ATG-KATKA and ATM-KATKA techniques increased the component size by a mean of 0.90 (SD 0.31, min 0.5 to max 1.5) (p<0.001) and 1.02 (SD 0.31, min 0.5 to max 1.5) (p<0.001), respectively. C-KATKA technique substantially proximally understuffed the trochleae with maximum values of 7.11mm (SD 1.39, min 3.93mm to max 10.57mm) in the medial facet, 4.72mm (SD 1.27, min 1.46mm to max 6.86mm) in the lateral facet and 4.51mm (SD 1.40, min 1.92mm to max 7.30mm) in the groove, respectively. Alternative techniques understuffed medial facet with maximum values of 5.07mm (SD 1.29, min 2.83mm to max 8.34mm) and 4.70mm (SD 1.52, min 0.83mm to max 8.04mm) for ATG-KATKA and ATM-KATKA techniques, respectively. There was no significant understuffing of the groove or lateral facet for alternative techniques (ATM and ATG). The ATM-KATKA and ATG-KATKA techniques generated mediolateral implant overhang, mainly postero-lateral, with a rate of 90.0% and 86.7%, respectively. In this study, no mediolateral implant overhang was found for C-KATKA. Discussion/conclusionThe C-KATKA technique substantially understuffs the native trochlear articular surfaces in medial, lateral and groove parts. Alternative techniques (ATM-KATKA and ATG-KATKA) for sizing the femoral component better restore the native trochlear anatomy but also generate a high rate of postero-lateral implant overhangs. Would this postero-lateral implant overhang be clinically deleterious remains unknown? The aspect ratio of contemporary femoral TKA implants can probably be optimized to allow a better anatomical restoration of the anterior femoral compartment. Level of evidenceII, in silico study.

Long-term outcome of total hip arthroplasty in patients with multiple hereditary exostosis.

Multiple hereditary exostosis (MHE) is a rare autosomal dominant disorder characterized by multiple osteochondromas. There is a paucity of literature concerning total hip arthroplasty (THA) in patients with MHE. The aim of this study is to report long-term outcomes of THA in patients with MHE. Fourteen patients undergoing 15 THA's for the treatment of osteoarthritis in the presence of osteochondromas and proximal femoral deformity secondary to MHE were reviewed. Mean age at the time of surgery and follow-up was 56 and 12years. Seven (47%) had uncemented femoral components. Eleven hips had coxa valga on preoperative imaging. Clinical outcomes were assessed with both Harris hip scores (HHS) and Musculoskeletal Tumor Society Scores (MSTS). Following surgery, there was an improvement in the HHS (48-82, p < 0.01) and MSTS scores (41-70%, p < 0.01). Complications occurred in 5 patients leading to reoperation in 3 patients, of which 2 patients underwent a revision procedure at 19 and 20-years postoperative. The 10-year revision free survival was 100%. THA in the setting of MHE reliably improves patient function. One in three patients will have a postoperative complication; however, the long-term incidence of revision is low.

A New Concept of Using Femoral Condyles Surface for Femoral Component Alignment During Total Knee Arthroplasty: A Technical Note.

Orthopedic surgeons favor an intramedullary guiding system on the femoral component during total knee arthroplasty (TKA); nevertheless, improper positioning of the entry point affects the final alignment. We have designed a new femoral cutting system for TKA that uses the distal and posterior femoral condyles as reference points for the setting of the cutting system regardless of the femoral canal. This study aims to evaluate the outcomes of this new guiding system. We enrolled a series of 75 consecutive knees undergoing TKA. The alpha, gamma, and hip-knee-ankle (HKA) angles were assessed three months postoperatively. Also, surgical time and intraoperative blood loss were recorded for all patients. Fifteen patients underwent TKA using the mechanical alignment (MA) strategy, and 60 underwent kinematically aligned (KA) TKA. Both groups showed normal coronal and sagittal alignment 3 months postoperatively. The mean intraoperative blood loss was 213.11 ± 52.73ml, which was not different between the two groups (n.s.). The mean surgical time was 43.12 ± 11.62min, which was significantly shorter in the KA-TKA (41.11 ± 3.77min) than in the MA-TKA (49.34 ± 4.56min) (P < 0.001). Using the new guiding system with good femoral alignment, we introduced the easily palpable and available condylar surface as a new landmark for cutting the distal femur in TKA. IV.

Fluoroscopy-guided direct anterior approach total hip arthroplasty provides more accurate component positions in the supine position than in the lateral position

PurposeThe position of the acetabular and femoral components is critical for stability and wear resistance. The aim of this study is to investigate whether the fluoroscopy-guided direct anterior approach in the supine position (S-DAA) is more helpful in improving the position of acetabular and femoral components than the fluoroscopy-guided direct anterior approach in the lateral decubitus position (L-DAA).MethodsA retrospective analysis of 76 cases of fluoroscopy-guided direct anterior approach total hip arthroplasty (38 cases in the S-DAA and 38 cases in the L-DAA group) was performed in one hospital from 2019 to 2021. The differences in inclination, anteversion, femoral offset (FO), global offset (GO), and leg length discrepancy (LLD) measurements during and after surgery were analyzed. The postoperative femoral offset (FO), global offset (GO), leg length discrepancy (LLD), and preoperative and postoperative Harris hip score were compared between the two groups.ResultsIn the S-DAA group, there were no significant differences in the mean intraoperative inclination angle anteversion angle, FO, GO, and LLD compared to the postoperative values, whereas in the L-DAA group, there were significant differences between the intraoperative and postoperative measurements (P < 0.001, P = 0.009, P＜0.001, P＜0.001 and P = 0.008, respectively). Additionally, there were significant differences in the accuracy of LLD, FO, and GO between the two groups (P < 0.001). Compared with the L-DAA group, the average differences of inclination, anteversion, LLD, FO, and GO during and after operation in the S-DAA group were smaller, and the consistency was higher. There was a significant difference in Harris hip score between the two groups at 1 week after surgery (P = 0.033). There was no significant difference in Harris hip score between 1 month and 3 months after surgery (P = 0.482 and P = 0.797, respectively).ConclusionsIn the supine group, the direct anterior approach (DAA) provides more accurate positioning of the acetabular and femoral components. However, there was no significant difference in hip joint function and activity between the two groups at follow-up.

Comparison of three-versus two-dimensional pre-operative planning for total hip arthroplasty

BackgroundA successful clinical outcome for total hip arthroplasty (THA) depends on accurate sizing and positioning of the implants. Using three-dimensional (3-D) pre-operative planning with a computerized tomography (CT) scan has many potential advantages over conventional 2-D planning using radiographs, including potentially more accurate assessments of the size and anteversion of the acetabulum, as well as lateral femoral offset. The purpose of this study was to compare the accuracy of 3-D to 2-D templating with respect to acetabular and femoral size, as well as lateral femoral offset. MethodsPre-operative templating data was collected prospectively from a consecutive series of 290 primary THAs (acetabulum on all, femoral component on 255 of the cases using one specific stem). All cases were initially templated on a digital imaging picture archiving and communication (PACS) system with calibrated images to estimate the acetabular size, femoral size, and lateral femoral offset. The 3-D templating was then performed with software based on a CT scan, and the results were compared to what was surgically implanted. ResultsThe 3-D templating for the acetabulum was accurate 99.7% of the time based on the final implanted component. The 2-D templating for the acetabulum was accurate 39% of the time, with 46% templating larger and 15% templating smaller than the final implanted component. The 3-D templating of the femoral component was accurate 63% of the time, and within one size of final implant in 96% of cases. The 2-D templating of the femoral component was accurate 53% of the time and within one size of final implant in 94% of cases. Lateral femoral offset consistently matched the 3-D plan, with a 100% match rate. The 2-D templated femoral offset was accurate 87% of the time and was changed in 13% of cases after 3-D templating. ConclusionThe CT-based 3-D preoperative planning was superior to 2-D planning for THA with respect to acetabular size, femoral size, and lateral femoral offset. Precise acetabular component sizing conserves bone and allows for a more predictable press fit, while facilitating efficient inventory management. Lateral femoral offset is often difficult to measure on 2-D images, and 3-D templating consistently allows for accurate offset restoration, which is important for normal hip function and stability.

Osteometric Dimension of Lower End of Femoral Bone among Bangladeshi Population

Introduction: The osteometric dimensions of the lower end of the femur have significant clinical implications, particularly in the context of total knee arthroplasty (TKA). Accurate measurements are crucial for the design of femoral components in TKA, which can influence surgical outcomes. This study aims to determine the measurements of different variables of the lower end of the femur, including femoral condylar width, intercondylar width and depth, and the depth of the medial and lateral condyles, in a Bangladeshi population. Methods: This cross-sectional study was conducted on 50 dried femurs collected from three medical colleges in Dhaka, Bangladesh. Measurements were obtained using digital sliding calipers and were rounded to two decimal places. Data analysis was performed using SPSS. Result: Statistical analysis revealed that 56% of the femurs were right-sided and 44% were left-sided. The mean femoral bicondylar width was 69.78 ± 5.38 mm, falling mostly in the "Above Average" range (30%). The mean intercondylar width was 23.77 ± 1.55 mm, with 50% falling in the "Medium" range. Other variables like femur medial condylar width had a mean of 31.05 ± 1.74 mm. Conclusion: Observationally, the study successfully delineates the osteometric dimensions of the lower end of the femur in a Bangladeshi cohort. The statistical results not only fulfill the study's initial aim but also provide a nuanced understanding of the osteometric variations. These findings are instrumental for clinicians in the design and customization of femoral components in TKA, thereby potentially enhancing surgical outcomes and patient satisfaction. The data also lay the groundwork for future research in this area.