Ye-Yeon Won

Age-and region-dependent changes in three-dimensional microstructural properties of proximal femoral trabeculae

SummaryThis study investigated regional variations in the 3D microstructure of trabecular bone in human proximal femur, with respect to aging. The results demonstrate that age-related changes in trabecular microstructure significantly varied from different sub-regions of the proximal femur.IntroductionWe hypothesize that the age-related changes in trabecular bone microstructure appear to be varied from specific anatomic sub-regions of the proximal femur followed by non-uniform bone loss. The purpose of this study was therefore to explore regional variations in the 3D microstructure of trabecular bone in human proximal femur, with respect to aging.MethodsA total of 162 trabecular bone cores from six regions of 27 femora of male cadaver donors were scanned using micro-computed tomography (micro-CT). The following microstructural parameters were calculated: bone volume fraction (BV/TV), trabecular number (Tb.N), thickness (Tb.Th) and separation (Tb.Sp), structure model index (SMI), and degree of anisotropy (DOA).ResultsAge-related changes in trabecular microstructure varied from different regions of the proximal femur. There was a significant decrease in bone volume fraction and an almost identical decrease in trabecular thickness associated with aging at any region. Regional analysis demonstrated a significant difference in BV/TV, Tb.Th, Tb.Sp, Tb.N and DOA between superior and inferior neck, as well as a significant difference in BV/TV, Tb.Sp, Tb.N, SMI and DOA between superior and inferior trochanter.ConclusionsAge-related changes in bone loss and trabecular microstructure within the male proximal femur are not uniform in this cadaveric population.

Maintenance of Increased Bone Mass After Recombinant Human Parathyroid Hormone (1‐84) With Sequential Zoledronate Treatment in Ovariectomized Rats

The concept of lose, restore, maintain (LRM) for reversing existing osteoporosis was tested in rats. The withdrawal of PTH results in the loss of the acquired bone mass, but sequential therapy with zoledronate quite effectively maintained the PTH(1‐84)‐acquired bone quantity and quality.

Pseudoaneurysm after tibial nailing.

This is a case report of a patient with a pseudoaneurysm of the anterior tibial artery after lateral to medial distal locking of an intramedullary nail for a tibia shaft fracture.

Assessment of Bone Quality using Finite Element Analysis Based upon Micro-CT Images

Background To evaluate the feasibility of a micro-image based finite element model to determine the efficacy of sequential treatments on the bone quality in a rat osteoporosis model. Methods Rat osteoporosis and treated osteoporosis models were established with the bone loss, restore and maintain concept. Thirty Sprague-Dawley rats were used in this study. A sham operation or ovariectomy was performed at 20 weeks after birth, which was followed by the respective sequential trials as follows: (1) sham-operation only, (2) ovariectomy only, (3) ovariectomized rats with parathyroid hormone maintenance, (4) ovariectomized rats treated with PTH for 5 weeks and then withdrawal, (5) ovariectomized rats treated with PTH for 5 weeks and then with 17 beta-estradiol, and (6) ovariectomized rats treated with parathyroid hormone for 5 weeks and then treated with zoledronate. The histomorphometry indices were determined using the micro-images from a micro-computed tomogram. Finite element analysis was carried out to determine the mechanical properties (Stiffness and Youngs modulus) of the vertebra bodies. The differences in properties between the groups were compared using ANOVA and a Bonferronis multiple group comparison procedure. Results The histomorphometry and mechanical properties were significantly better in groups (3) and (6) than in the groups (1) and (2) (p < 0.05). The stiffness (σs) and Youngs modulus (E) was highest in group (3) following by group (6). Conclusions Finite element analysis based on micro-images provides a useful tool that reflects the changes in micro-structural and mechanical properties of a rat vertebral body with the bone loss, restore and maintain concept.

Does Zoledronate Prevent Femoral Head Collapse from Osteonecrosis? A Prospective, Randomized, Open-Label, Multicenter Study.

BACKGROUND Osteonecrosis of the femoral head frequently leads to collapse of the necrotic portion and subsequent degenerative joint disease of the hip, which is the most common diagnosis leading to total hip arthroplasty in young adults. Bisphosphonate therapy has been reported to potentially retard the collapse. We conducted a two-year prospective, randomized, open-label, multicenter study to determine whether zoledronate prevents the collapse and reduces the need for total hip arthroplasty. METHODS We randomly assigned patients who had Steinberg stage-I or II nontraumatic osteonecrosis of the femoral head with a necrotic area of ≥30% to either the zoledronate group or the control group. Patients in the zoledronate group received 5 mg of zoledronate intravenously per year for two years, while patients in the control group did not receive this medication. The primary efficacy outcome was the survival rate in terms of the occurrence of collapse (≥2 mm). The patients were observed for a minimum of two years after enrollment. RESULTS A total of 110 patients (110 hips) underwent randomization; fifty-five patients were assigned to the zoledronate group and fifty-five, to the control group. During the two-year follow-up, twenty-nine femoral heads in the zoledronate group and twenty-two in the control group collapsed (p > 0.05). Nineteen hips in the zoledronate group and twenty in the control group underwent total hip arthroplasty (p > 0.05). CONCLUSIONS Zoledronate for Steinberg stage-I or II osteonecrosis of the femoral head, with a medium to large necrotic area, did not prevent the collapse of the femoral head or reduce the need for total hip arthroplasty. LEVEL OF EVIDENCE Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Navigation-Assisted Total Knee Arthroplasty for the Knee Retaining Femoral Intramedullary Nail, and Distal Femoral Plate and Screws

Proper ligament balancing, restoration of the mechanical axis and component alignment are essential for the success and longevity of a prosthesis. In conventional total knee arthroplasty (TKA), an intramedullary guide is used to improve the alignment. An extramedullary guide can be used in cases of severe femoral bowing or intramedullary nailing but its use is more subjective and relies on the surgeons experience. This paper reports two successful cases of navigation-assisted TKA for severe right knee osteoarthritis retaining a femoral intrameullary nail, and left knee osteoarthritis retaining a distal femoral plate.

Kinematic alignment is a possible alternative to mechanical alignment in total knee arthroplasty

PurposeA systematic review was conducted to answer the following questions: (1) Does kinematically aligned (KA) total knee arthroplasty (TKA) achieve clinical outcomes comparable to those of mechanically aligned (MA) TKA? (2) How do the limb, knee, and component alignments differ between KA and MA TKA? (3) How is joint line orientation angle (JLOA) changed from the native knee in KA TKA compared to that in MA TKA?MethodsNine full-text articles in English that reported the clinical and radiological outcomes of KA TKA were included. Five studies had a control group of patients who underwent MA TKA. Data on patient demographics, clinical scores, and radiological results were extracted. There were two level I, one level II, three level III, and three level IV studies. Six of the nine studies used patient-specific instrumentation, one study used computer navigation, and two studies used manual instrumentation.ResultsThe clinical outcomes of KA TKA were comparable or superior to those of MA TKA with a minimum 2-year follow-up. Limb and knee alignment in KA TKA was similar to those in MA TKA, and component alignment showed slightly more varus in the tibial component and slightly more valgus in the femoral component. The JLOA in KA TKA was relatively parallel to the floor compared to that in the native knee and not oblique (medial side up and lateral side down) compared to that in MA TKA. The implant survivorship and complication rate of the KA TKA were similar to those of the MA TKA.ConclusionSimilar or better clinical outcomes were produced by using a KA TKA at early-term follow-up and the component alignment differed from that of MA TKA. KA TKA seemed to restore function without catastrophic failure regardless of the alignment category up to midterm follow-up. The JLOA in KA TKA was relatively parallel to the floor similar to the native knee compared to that in MA TKA. The present review of nine published studies suggests that relatively new kinematic alignment is an acceptable and alternative alignment to mechanical alignment, which is better understood. Further validation of these findings requires more randomized clinical trials with longer follow-up.Level of evidenceLevel II.

Comparison of Proximal Porous-Coated and Grit-Blasted Surfaces of Hydroxyapatite-Coated Stems

BACKGROUND It remains controversial whether a proximal porous coating is superior to a grit-blasted surface with regard to providing femoral stem fixation in total hip arthroplasty. We examined the hypothesis that a proximal porous coating would provide better fixation than would a fully grit-blasted surface of otherwise identical proximally hydroxyapatite-coated stems. METHODS In a prospective study, seventeen patients (thirty-four hips) underwent bilateral sequential total hip replacement with the Anatomic Porous Replacement at the same operation. A proximally porous-coated femoral stem was implanted on one side, and a stem of the same design but with a proximal grit-blasted surface was implanted in the contralateral hip. A proximal hydroxyapatite coating was applied to the metallic substrate of both stems. The patients were followed for a mean 2.5 years and then were assessed radiographically and clinically with the Harris hip score. RESULTS With the numbers available, no significant clinical or radiographic differences were found between the two cohorts. Thirty of the thirty-four hips had an excellent result, two were rated good, and two were rated fair. All hips had stable osseous fixation of the stem radiographically. The two types of stems were associated with the same pattern of adaptive bone-remodeling. CONCLUSIONS In the first two years following total hip arthroplasty, hydroxyapatite-coated proximally porous-coated femoral stems do not provide fixation that is superior to that provided by hydroxyapatite-coated grit-blasted stems. LEVEL OF EVIDENCE Therapeutic study, Level II-1 (prospective cohort study). See Instructions to Authors for a complete description of levels of evidence.

A biomechanical study of osteoporotic vertebral trabecular bone : The use of micro-CT and high-resolution finite element analysis

Osteoporosis is one of the most dangerous skeletal diseases in relation to the highest fracture risk in vertebral bones. A considerable amount of work has been done to investigate the biomechanical characteristics of osteoporotic vertebral trabecular bone. Previous researchers studied the elastic characteristics using a micro-finite element (micro-FE) model, used to analyze realistic trabecular architectures in full detail, based on micro-computed tomography (μCT). Since osteoporotic compression fracture is closely associated with the mechanical characteristics of the vertebral trabecular bone and there were few micro-FE models to account for all of the elastic and plastic characteristics in vertebral trabecular bone, this study analyzed the effect of voxel resolution on the plastic characteristics as well as the elastic characteristics of three-dimensional (3D) osteoporotic lumbar trabecular bone models. Also, we evaluated the effect of specimen geometry on this problem. It has been reported that a cubic specimen with side length 6.5mm was suggested as standard specimens for the experimental test of trabecular bone. Current study examined whether or not the effect of the specimen geometry on the experimental test may be also applied to the simulated compression test of trabecular bone specimens. The experimental test employing the rapid prototyping (RP) technique and INSTRON test machine is performed to indirectly validate the results of the simulated compression test by micro-FE analysis. The review finished with the verification about the effects of the simulated compression test.

Sarcopenia and Osteoporosis.

Public health strategies designed to accomodate the ever-increasing human lifespan are urgently required. A good clinical understanding of frailty, as well as knowledge regarding how to prevent it, will therefore be required in order to overcome this challenge. Sarcopenia is an important component of the frailty syndrome, and its association with osteoporosis can lead to fractures and incident disability. Therefore, this review examined the literatuire pertaining to the association of sarcopenia with osteoporosis in order to assess preventive strategies.