Femoral Surface Research Articles

Effect of malaligned knee prosthesis on stress and fatigue life of tibial tray

Among various health care demands for ageing population, the total knee arthroplasty (TKA) is currently one of the major health care expenses. TKA is a process to replace the surfaces of femur and tibia with the knee prosthesis, i.e., femoral component, tibial tray, and spacer. During service, the metal tibial tray is under cyclic bending; thus, the fatigue failure is possible. The cyclic bending and fatigue failure of tibial tray can be enhanced by the malalignment of knee prosthesis due to the change of bodily structure in ageing population. To investigate the influence of malaligned knee prosthesis on fatigue life, the numerical stress analysis and in-vitro fatigue test of tibial tray based on ASTM F1800 were performed. For tibial trays with malalignments, the location of the maximum stress range was near the junction between stem and tray, which corresponded to the location of fractures observed previously in clinical application.

Intraoperative analysis of patellofemoral joint morphology before and after total knee arthroplasty : Afeasibility study.

BackgroundPatellofemoral problems after total knee arthroplast (TKA) are frequent and often associated with a change in the geometry of the trochlear groove.ObjectiveThe present study aimed to analyze the feasibility of intraoperative examination of the patellofemoral joint geometry before and after the implantation of bicondylar total knee replacements without exposing the patient to radiation.Material and methodsThe patellofemoral joint morphology geometries of 33 patients before and after implantation of a bicondylar total knee replacement was intraoperatively analyzed using a digital scanning method. Femoral surface geometries were extracted from intraoperatively recorded tactile scanning data using an in-house algorithm. The geometries were then characterized by sulcus height, medial femoral condyle height and lateral femoral condyle height.ResultsOur preliminary results show that these key geometric parameters are only partially restored after TKA leading to a distinctly different shaped profile of the anterior distal femur. Maximum and minimum mean differences in sulcus height, medial femoral condyle height, and lateral femoral condyle height before and after surgery were 2.00 mm/−3.06 mm, 2.51 mm/−6.25 mm and 2.74 mm/−3.58 mm, respectively.ConclusionA new method for intraoperative analysis of the patellofemoral joint morphology before and after TKA without radiation exposure was developed and utilized. Even with the use of modern total knee designs, the patellofemoral articulation is considerably changed postoperatively as quantified by the key parameters of sulcus height, medial femoral condyle height, and lateral femoral condyle height. This may result in altered knee biomechanics and might explain persistent patellofemoral disorders, which are often reported by patients after TKA.

Patellofemoral Arthroplasty: A Technical Note

Background: Patellofemoral arthroplasty (PFA) is a salvage procedure for patients presenting with bone-on-bone isolated patellofemoral osteoarthritis. Previous studies comparing PFA with total knee arthroplasties found that patients recover more quickly and have better average knee function following PFA, as care is taken to spare healthy cartilage, bone, and ligaments during the procedure. This allows preservation of native knee kinematics, resulting in better patient-reported outcomes, as well as mid-term and long-term results. Indication: PFA is indicated in patients with isolated primary or post-traumatic patellofemoral osteoarthritis. In some cases, the procedure may be indicated in patients suffering from patellar instability or trochlear dysplasia with associated arthritis. Contraindications for PFA include multicompartmental arthritis in the medial or lateral tibiofemoral compartments, inflammatory joint disease, tibiofemoral instability, malalignment, or lesions of 6 mm or more in diameter. Technique Description: After the initial lateral patellofemoral approach, degenerative changes in the patellofemoral joint were observed. Following preparation of the patella and femur, the trochlear implant is impacted on the prepared femoral surface. Cement is digitally impacted into the reamed patella, followed by placement of the final patellar implant and compression until the cement is dried. Results: Within 2 years postoperatively, patients are expected to have improved overall knee-specific quality of life, reduced pain, and a successful return to activities. Discussion/Conclusion: New PFA techniques have yielded significant improvement in patient-reported outcomes and high rates of survivorship following surgery.

Primary total knee arthroplasty assisted by computed tomography-free navigation for secondary knee osteoarthritis following massive calcium phosphate cement packing for distal femoral giant-cell bone tumor treatment: a case report

BackgroundGiant cell tumor of bone (GCTB) is an intermediate tumor commonly arising from the epiphysis of the distal femur and proximal tibia. Standard GCTB treatment is joint-preserving surgery performed using thorough curettage and the filling of the cavity with allo-, auto-, polymethyl methacrylate (PMMA), or synthetic bone graft. Calcium phosphate cement (CPC) is an artificial bone substitute, which has the benefit of being able to adjust defects, consequently inducing immediate mechanical strength, and promoting biological healing. Secondary osteoarthritis may occur following GCTB treatment and may need additional surgery if severe. However, details regarding surgery for secondary osteoarthritis have not been fully elucidated. There are no reports on the use of total knee arthroplasty (TKA) for the treatment of secondary osteoarthritis following CPC packing. The insertion of an alignment rod is a standard procedure in TKA; however, it was difficult to perform in this case due to CPC. Therefore, we used a computed tomography (CT)-free navigation system to assist the distal femur cut. This study presents a knee joint secondary osteoarthritis case following CPC packing for GCTB curettage that was treated with standard TKA.Case presentationA 67-year-old Japanese woman, who was previously diagnosed with left distal femur GCTB and was treated by curettage and CPC packing 7 years ago, complained of severe knee pain. Left knee joint plain radiography revealed Kellgren and Lawrence (K-L) grade 4 osteoarthritis without evidence of tumor recurrence. Therefore, she was scheduled for TKA. There are no reports on the cutting of a femoral condyle surface with massive CPC with accurate alignment. Because it is difficult to insert the alignment rod intramedullary and cut the femoral condyle with CPC, we planned CT-free navigation-guided surgery for accurate bone cutting using an oscillating tip saw system to prevent CPC cracks. We performed standard TKA without complications, as planned. Postoperative X-ray showed normal alignment. Knee Society Knee Score (KSKS) and Knee Society Function Score (KSFS) ameliorated from 27 and 29 to 64 and 68, respectively The patient can walk without a cane postoperatively.ConclusionThere was no report about the surface TKA guided by CT-free navigation after primary GCT surgery with CPC. We believe that this case report will help in planning salvage surgery for secondary osteoarthritis after CPC packing.

Hagenulopsis Ulmer (Ephemeroptera: Leptophlebiidae): re-description, morphological notes and a new species from South America, Brazil.

Hagenulopsis diptera Ulmer, type species of the genus Hagenulopsis, was originally described based on imagos from Santa Catarina State, Southern Brazil. Misconceptions of H. diptera circumscription led to erroneous attribution of material from Minas Gerais and Esprito Santo, Southeastern Brazil, to H. diptera. Despite the increase in the number of species attributed to Hagenulopsis, little attention has been given to the type species. After comparative examination of photographs of the holotype and fresh material of H. diptera from Southeastern Brazil, we conclude that many specimens previously assigned to H. diptera represent a new species. Thus, we redescribe H. diptera and describe a new species Hagenulopsis perere sp. nov. based on eggs, nymphs and imagos. Diagnostic features of Hagenulopsis perere sp. nov. include cross veins between C and RP1 strongly clouded with brown and outer surface of mid femur with a brown spot at midlength. Finally, comments and new records are presented for Hagenulopsis minuta Spieth.

Personalised 3D Assessment of Trochanteric Soft Tissues Improves HIP Fracture Classification Accuracy

Passive soft tissues surrounding the trochanteric region attenuate fall impact forces and thereby control hip fracture risk. The degree of attenuation is related to Soft Tissue Thickness (STT). STT at the neutral hip impact orientation, estimated using a regression relation in body mass index (BMI), was previously shown to influence the current absolute risk of hip fracture (ARF0) and its fracture classification accuracy. The present study investigates whether fracture classification using ARF0 improves when STT is determined from the subject’s Computed-Tomography (CT) scans (i.e. personalised) in an orientation-specific (i.e. 3D) manner. STT is calculated as the shortest distance along any impact orientation between a semi-automatically segmented femur surface and an automatically segmented soft tissue/air boundary. For any subject, STT along any of the 33 impact orientations analysed always exceeds the value estimated using BMI. Accuracy of fracture classification using ARF0 improves when using personalised 3D STT estimates (AUC = 0.87) instead of the BMI-based STT estimate (AUC = 0.85). The improvement is smaller (AUC = 0.86) when orientation-specificity of CT-based STT is suppressed and is nil when personalisation is suppressed instead. Thus, fracture classification using ARF0 improves when CT is used to personalise STT estimates and improves further when, in addition, the estimates are orientation specific.

MRI evaluation of meniscal injuries of knee with arthroscopy correlation: A comparative study in a tertiary care hospital

Among various osseous, ligamentous structures around knee meniscus play important role in decreasing load on articular cartilage, smooth movement, reducing friction between opposing articular surfaces of femur, tibia during movement. An accurate diagnosis regarding site, type, grade of meniscal tear along with other associated injury is essential for early operative treatment or non-operative conservative management. This was a descriptive retrospective comparative study to determine the role of MRI in evaluating spectrum and grading of meniscal injuries of knee joint and correlate the findings with arthroscopy. A total of 30 patients clinically suspected of having meniscal injury were evaluated over a period of 1 ½ year from July 2018 to December 2019. Clinical evaluation for meniscal injury with emphasis on medial and lateral joint tenderness, McMurrey test, Appley grinding test were performed by experienced an orthopedician. MRI was performed on 1.5 tesla machine followed by arthroscopy in all patients. Taking arthroscopy as gold standard; sensitivity, specificity, PPV, NPV, accuracy of MRI was determined. In our study, most common meniscal injury was medial meniscal injury (63.3%). Lateral meniscal injury comprised of 33.3%, both menisci were injured in 3.3% of cases. Most common type of tear was longitudinal tear and Grade III tear was most common in both medial and lateral menisci. The sensitivity, specificity, PPV, NPV accuracy of MRI for medial meniscal injury was 94.4%, 83.3%, 89.5%, 90.5%, 90.5%. The sensitivity, specificity, PPV, NPV accuracy of MRI for lateral meniscal injury was 90.0%, 95.0%, 90.0%, 95.0%, 93.3%. There is a good correlation between MRI and arthroscopy findings for meniscal injuries thus supporting MRI as excellent primary non invasive diagnostic tool prior to any invasive arthroscopy.

Extensive penile skin necrosis after surgery for Peyronie's disease

The clinical case represents the surgical correction of postoperative complications in a patient with Peyronie's disease. The patient underwent flap corporoplasty using an autovein. The late postoperative period in the patient was complicated by extensive necrosis of the penile skin, which required repeated surgery as follows. The first stage of surgical treatment was performed by excision of necrotic tissues of the penile skin. Within 10 days of the postoperative period, chymotrypsin with an ointment containing dioxomethyltetrahydropyrimidine with chloramphenicol was applied to the penile wound surface to prepare the wound for subsequent skin autotransplantation. Further, within 5 days, the polymeric drainage sorbent «Aseptisorb DT» was applied to the wound surface until the wound was cleansed and granulation tissue was formed. The second stage of the surgical treatment performed penile skin replacement plasty with a free perforated skin graft taken from the patient's femoral surface.

Three-dimensional morphometric differences of resected distal femurs and proximal tibias in osteoarthritic and normal knees

BackgroundThere is a paucity of data concerning the morphological differences of resected distal femurs and proximal tibias in osteoarthritic (OA) and normal knees. The objective of this study was to determine whether morphometric differences in the surfaces of resected distal femurs and proximal tibias exist between OA and normal knees in a Chinese population.MethodsNinety-four OA knees and ninety-five normal knees were evaluated in Chinese individuals. Computed tomography was used to measure the femoral mediolateral (fML), medial anteroposterior (fMAP), lateral anteroposterior (fLAP), medial condylar width (fMCW), lateral condylar width (fLCW), medial posterior condylar curvature radii (fMCR), lateral posterior condyle curvature radii (fLCR), fML/fMAP aspect ratio, tibial mediolateral (tML), middle anteroposterior (tAP), medial anteroposterior (tMAP), and lateral anteroposterior (tLAP) tML/tMAP aspect ratio to determine the morphologic differences between OA and normal knees.ResultsThe average fMCW and tMAP dimensions of OA knees were larger than those of normal knees in both male and female (p <0.05). The fMAP/fML aspect ratio and tMAP/tML aspect ratio were also significantly different in both sexs (p <0.05). OA knees have an oval-shaped distal femur with a wider ML length and more spherical-shaped proximal tibiae with relatively narrow ML dimensions.ConclusionsThe study revealed the morphological differences in fMCW, tMAP, fMAP/fML and tMAP/tML between OA and normal knees in both males and females. These findings may provide guidelines that can be used to design better knee implants that are more size-matched for OA knees.

Topology Optimisation for Compliant Hip Implant Design and Reduced Strain Shielding.

Stiff total hip arthroplasty implants can lead to strain shielding, bone loss and complex revision surgery. The aim of this study was to develop topology optimisation techniques for more compliant hip implant design. The Solid Isotropic Material with Penalisation (SIMP) method was adapted, and two hip stems were designed and additive manufactured: (1) a stem based on a stochastic porous structure, and (2) a selectively hollowed approach. Finite element analyses and experimental measurements were conducted to measure stem stiffness and predict the reduction in stress shielding. The selectively hollowed implant increased peri-implanted femur surface strains by up to 25 percentage points compared to a solid implant without compromising predicted strength. Despite the stark differences in design, the experimentally measured stiffness results were near identical for the two optimised stems, with 39% and 40% reductions in the equivalent stiffness for the porous and selectively hollowed implants, respectively, compared to the solid implant. The selectively hollowed implant’s internal structure had a striking resemblance to the trabecular bone structures found in the femur, hinting at intrinsic congruency between nature’s design process and topology optimisation. The developed topology optimisation process enables compliant hip implant design for more natural load transfer, reduced strain shielding and improved implant survivorship.

3D Geometric Shape Reconstruction for Revision TKA and UKA Knees Using Gaussian Process Regression.

Revision knee surgery is complicated by distortion of previous components and removal of additional bone, potentially causing misalignment and inappropriate selection of implants. In this study, we reconstructed the native femoral and tibial surface shapes in simulated total/unicompartmental knee arthroplasty (TKA/UKA) for 20 femurs and 20 tibias using a statistical inference methodbased on Gaussian Process regression. Compared to the true geometry, the average absolute errors (mean absolute distances) in the prediction of resected femur bones in TKA, medial UKA, and lateral UKA were 1.0 ± 0.3 mm, 1.0 ± 0.3 mm, and 0.8 ± 0.2 mm, respectively, while those in the prediction of tibia resections in the corresponding surgeries were 1.0 ± 0.4 mm, 0.8 ± 0.2 mm, and 0.7 ± 0.2 mm, respectively. Furthermore, it was found that the prediction accuracy depends on the size and gender of the resected bone. For example, the prediction accuracy for UKA cuts was significantly better than that for TKA cuts (p < 0.05). The female and male cuts were often overfit and underfit, respectively. The data indicated that this reconstruction approach can be a viable option for planning of revision surgeries, especially when contralateral anatomy is pathological or cannot be available.

Description of the second- and third-instar larvae of Hydrovatus crassulus Sharp, 1882 (Coleoptera: Dytiscidae: Hydrovatini).

The second- and third-instar larvae of the diving-beetle species Hydrovatus crassulus Sharp, 1882 are described and illustrated, including detailed morphometric and chaetotaxic analyses of the cephalic capsule, head appendages, legs, last abdominal segment and urogomphi. Larvae of this species lack the parietal pore PAo, the premental seta LA3 and the urogomphal seta UR8, and have the sensillum MN2 shaped as a short hair-like seta and the ventral surface of the abdominal segments IIV sclerotized. All these characteristics are shared with the other species of Hydrovatus Motschulsky, 1853 known in detail (H. caraibus Sharp, 1882) and therefore are considered diagnostic for the genus. Hydrovatus crassulus also characterizes by the presence of a small galea, which reinforces the hypothesis that this structure is part of the ancestral condition of Hydrovatus. Larvae of H. crassulus differ from those of H. caraibus in having a smaller size, a smaller ratio U/LAS, and a larger ratio U1/U2, and also in the presence (in most cases) of a secondary seta on the anteroventral surface of femur.

MRI-- and CT--based metrics for the quantification of arthroscopic bone resections in femoroacetabular impingement syndrome.

The purpose of this in vitro study was to quantify the bone resected from the proximal femur during hip arthroscopy using metrics generated from magnetic resonance imaging (MRI) and computed tomography (CT) reconstructed three-dimensional (3D) bone models. Seven cadaveric hemi-pelvises underwent both a 1.5 T MRI and CT scan before and following an arthroscopic proximal femoral osteochondroplasty. The images from MRI and CT were segmented to generate 3D proximal femoral surface models. A validated 3D--3D registration method was used to compare surface--to--surface distances between the 3D models before and following surgery. The new metrics of maximum height, mean height, surface area and volume, were computed to quantify bone resected during osteochondroplasty. Stability of the metrics across imaging modalities was established through paired sample t--tests and bivariate correlation. Bivariate correlation analyses indicated strong correlations between all metrics (r = 0.728--0.878) computed from MRI and CT derived models. There were no differences in the MRI- and CT-based metrics used to quantify bone resected during femoral osteochondroplasty. Preoperative- and postoperative MRI and CT derived 3D bone models can be used to quantify bone resected during femoral osteochondroplasty, without significant differences between the imaging modalities.

Total Meniscus Reconstruction Using a Polymeric Hybrid-Scaffold: Combined with 3D-Printed Biomimetic Framework and Micro-Particle.

The meniscus has poor intrinsic regenerative capability, and its injury inevitably leads to articular cartilage degeneration. Although there are commercialized off-the-shelf alternatives to achieve total meniscus regeneration, each has its own shortcomings such as individualized size matching issues and inappropriate mechanical properties. We manufactured a polycaprolactone-based patient-specific designed framework via a Computed Tomography scan images and 3D-printing technique. Then, we completed the hybrid-scaffold by combining the 3D-printed framework and mixture micro-size composite which consists of polycaprolactone and sodium chloride to create a cell-friendly microenvironment. Based on this hybrid-scaffold with an autograft cell source (fibrochondrocyte), we assessed mechanical and histological results using the rabbit total meniscectomy model. At postoperative 12-week, hybrid-scaffold achieved neo-meniscus tissue formation, and its shape was maintained without rupture or break away from the knee joint. Histological and immunohistochemical analysis results showed obvious ingrowth of the fibroblast-like cells and chondrocyte cells as well as mature lacunae that were embedded in the extracellular matrix. Hybrid-scaffolding resulted in superior shape matching as compared to original meniscus tissue. Histological analysis showed evidence of extensive neo-meniscus cell ingrowth. Additionally, the hybrid-scaffold did not induce osteoarthritis on the femoral condyle surface. The 3D-printed hybrid-scaffold may provide a promising approach that can be applied to those who received total meniscal resection, using patient-specific design and autogenous cell source.

PTH1-34 improves devitalized allogenic bone graft healing in a murine femoral critical size defect

The treatment of large segmental defects of long bones resulting from trauma, infection, or bone tumor resections is a major challenge for orthopedic surgeons. The reconstruction of bone defects with acellular allografts can be used as an osteoconductive approach. However, devitalized allografts are associated with high rates of clinical failure as a result of poor intrinsic osteoinduction properties and a lack of further remodeling. Nevertheless, evidence suggests that due to its anabolic properties, teriparatide (PTH1-34) could be effective as an adjuvant therapy for massive allograft healing. Therefore, our goal was to investigate in a murine critical-sized defect model whether the intermittent administration of PTH1-34 improves the incorporation and revitalization of acellular structural bone allografts. Thus, a 2.5-mm critical-sized defect was established in the right femur of C57BL/6 mice, followed by the reconstruction with a devitalized cortical structural allograft. A titanium micro locking plate was applied to the anterior femoral surface and secured in place with self-tapping locking screws. Subsequently, daily doses of PTH1–34 (30, and 40 µg/kg) or saline were administered to the mice for 14 days after surgery. The mice were maintained without PTH1–34 therapy for an additional 7 days before being euthanized at 3 weeks post-surgery. Bone graft consolidation was assessed on radiographic images and by histomorphometric analysis. Additionally, to determine the frequency of osteoprogenitor cells in the bone marrow and their in vitro osteogenic capacity, stromal cells were isolated from the bone marrow of animals treated with 30 or 40 µg/kg/day of PTH1-34 following the same protocol used for the experimental animals. Our results suggest that intermittent PTH1-34 treatment at 30 µg/kg/day after femoral allograft reconstruction surgery accelerated the healing process as evidenced by new bone formation induced on endosteal and periosteal surfaces, enhanced revitalization of allogeneic graft, and increased frequency and osteogenic capacity of bone marrow stromal cells (BMSC). These findings should encourage further studies aimed at investigating the potential therapeutic use of intermittent PTH1-34, specifically with regards to the optimal dosing regimen in clinically challenging orthopedic scenarios.

English

BACKGROUND The peculiar waddling gait of a female attracts most of the anatomists to measure and compare the neck-shaft angle (NSA) of the femora. The femoral neck shaft angle is greater in women due to greater pelvic breadth and shorter femur. Neck-shaft angle was measured by the angle that the neck makes with the shaft of the femur and it is measured on the ventral surface of femur taking the long axis of femoral neck with the long axis of the proximal end of the femur. It gives information about the race it belongs to and normally measures 120° to 140°. The intention of this study was to establish the femoral neck shaft angle variations in adult male and female for medico-legal and anthropometric studies. METHODS This cross-sectional study was conducted on 84 adult human femora of unknown sex in the anatomy department, Sriram Chandra Bhanja (SCB) Medical College, Cuttack, Odisha, from May 2018 to April 2019. We included all the femora which were free of damage or deformity and fully ossified indicating adult bone. Femora with any pathological changes i.e., cortical bone deterioration, extreme osteophyte activity, osteoarthritis and fracture etc. were excluded from the study. The NSA was measured by protractor and goniometer. RESULTS In the present study the NSA range for the right femur of male was 108° - 135° and for the right femur of females 117° - 135°. The left male femur was 118° - 135° and the left female femur was 120° - 135°. The mean neck shaft angle of male femora was 125.9° and the female femora was 125.7°. These measurements show that the values were more in males than the females. The value of the present study was statistically significant between male and female i.e., P &lt; 0.0001. CONCLUSIONS These measurements are important in the medico-legal cases, reconstructive orthopaedic surgeries, hip replacement surgeries and also while constructing suitable prosthesis. This will also be helpful in the detection of sex by anatomists and forensic experts. KEY WORDS Neck Shaft Angle, Medico-Legal, Anthropometry and Goniometer

Epiphyseal enchondroma masking as osteoid osteoma: a case report

BackgroundEnchondromas originating in the epiphyses of long bones are rare and epiphyseal osteoid osteomas are also uncommon. Diagnosis can become elusive when enchondromas or osteoid osteomas occur in atypical locations and present with nonspecific clinical and imaging characteristics.Case presentationWe report a case of epiphyseal enchondroma of the left proximal femur in a 15-year-old girl with a 2-month history of left lower extremity pain. Preoperative CT displayed thickened cortex in the anterior surface of the left proximal femur with specks of calcification and inhomogeneity of the adjacent bone marrow cavity. She was diagnosed with osteoid osteoma. Postoperative pathological examination of surgically excised specimens revealed a diagnosis of enchondromas.ConclusionsOur case highlights that enchondroma should be considered in lesions of the epiphysis.

Gender-Based Quantitative Analysis of the Grand Piano Sign in Mechanically Aligned Total Knee Arthroplasty in Asians.

In mechanically aligned (MA) total knee arthroplasty (TKA), the grand piano sign helps surgeons to further ensure the proper external rotation of the femoral component. The goal of this study was to determine the sex-related differences in the shape of the anterior resection surface using 3D magnetic resonance imaging (MRI) models. MRI scans were performed on 267 consecutive patients (202 women and 65 men) with osteoarthritis who underwent TKA in order to reconstruct a 3D model. Virtual anterior condylar resection was performed based on the surgical transepicondylar axis (sTEA), Whiteside’s line (WSL), and flexion-extension axis (FEA). On the anterior resection surface, both lateral length (LatL) and medial length (MedL) were measured, and the ratio between the two (MedL/LatL) was calculated. The mediolateral width of the distal femur (ML) and anterior resection surface (M′L′) were measured, and the ratio between the M′L′ and ML (M′L′/ML) was calculated. Both the lateral deviation (LD) and the ratio between LD and ML (LD/ML) were also determined. Morphological classification of the anterior resection surface was conducted based on the presence of a definite medial peak. When based on the sTEA or WSL, the MedL/LatL of female subjects was significantly greater than that of male subjects (p < 0.001 and p < 0.05, respectively). The MedL/LatL of the FEA was consistently larger than that obtained using the sTEA or WSL. Among female subjects, the MedL/LatL of the sTEA was significantly greater than that of the WSL, although this was not the case in either the total study population or the male subjects alone. When based on the sTEA, the M′L′/ML was statistically greater in the female subjects (p < 0.01). The LD was greater in the male subjects (p < 0.01), but there was no difference between the male and female subjects when comparing the LD/ML (p = 0.93). The proportion of double- and single-peak types was not significantly different between the sexes (p = 0.196). Surgeons should be aware that the shape of the anterior resection surface may differ depending on the sex of the patient. The results of this study provide more consistent surgical outcomes as well as fundamental anatomical data for designing suitable prostheses applicable to the Korean population.

OSTEOCHONDROMA FRACTURE IN YOUNG ATHLETE: A CASE REPORT

Background: Osteochondroma is a benign bone tumor that most cases are asymptomatic. The symptoms may occur as a complication of osteochondroma, which is rarely happened. Surgical intervention is needed to treat the complications.Case: A 20-year old male football athlete presented with pain on his left thigh's lump after he fell during his training. Mass and tenderness on the medial side of the left distal femur were found. Plain X-Ray showed an irregular mass on the left distal femur's surface with a fracture through the stalk of pedunculated osteochondroma. The patient underwent total excision of the osteochondroma.Discussion: The fracture of the osteochondroma often occurs in teenagers because they are more active physically. It happens due to direct or indirect injury. The treatment of this fracture is controversial between observation or surgical excision. In this case report, the patient could demonstrate full weight-bearing right after the surgery.Conclusion: Fracture as a complication in osteochondroma often happens to teenagers, and surgery proved to give a good outcome in this case.

Fast and Accurate Registration of the Proximal Femurs in Bilateral Hip Joint Images by Using the Random Sub-Sample Points

Background and ObjectiveAs is known, point clouds representing the objects are frequently used in object registration. Although the objects can be registered by using all the points in the corresponding point clouds of the objects, the registration process can also be achieved with a smaller number of the landmark points selected from the entire point clouds of the objects. This paper introduces a research study focusing on the fast and accurate rigid registration of the bilateral proximal femurs in bilateral hip joint images by using the random sub-sample points. For this purpose, Random Point Sub-sampling (RPS) was analyzed and the reduced point sets were used for an accurate registration of the bilateral proximal femurs in coronal hip joint magnetic resonance imaging (MRI) slices. MethodsIn registration, bilateral proximal femurs in MRI slices were registered rigidly by performing a process consisting of three main phases named as MR image preprocessing, proximal femur registration over the random sub-sample points and MR image postprocessing. In the stage of the MR image preprocessing, segmentation maps of the bilateral proximal femurs are obtained as region of interest (RoI) images from the entire MRI slices and then, the edge maps of the segmented proximal femurs are extracted. In the registration phase, the edge maps describing the proximal femur surfaces are represented as point clouds initially. Thereafter, the RPS is performed on the proximal femur point clouds and the number of points representing the proximal femurs is reduced at different ratios. For the registration of the point clouds, the Iterative Closest Point (ICP) algorithm is performed on the reduced sets of points. Finally, the registration procedures are completed by performing MR image postprocessing on the registered proximal femur images. ResultsIn performance evaluation tests performed on healthy and pathological proximal femurs in 13 bilateral coronal hip joint MRI slices of 13 Legg-Calve-Perthes disease (LCPD) patients, bilateral proximal femurs were successfully registered with very small error rates by using the reduced set of points obtained via the RPS and promising results were achieved. The minimum error rate was observed at RPS rate of 30% as the value of 0.41 (±0.31)% on all over the bilateral proximal femurs evaluated. When the range of RPS rate of 20-30% is considered as the reference, the elapsed time in registration can be reduced by almost 30-40% compared to the case where all the proximal femur points were included in registration. Additionally, it was observed that the RPS rate should be selected as at least 25% to achieve a successful registration with an error rate below 1%. ConclusionIt was concluded from the observed results that a more successful and faster registration can be accomplished by selecting fewer points randomly from the point sets of proximal femurs instead of using all the points describing the proximal femurs. Not only an accurate registration with low error rates was performed, but also a faster registration process was performed by means of the limited number of points that are sub-sampled randomly from the whole point sets.