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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_8 | Pages 126 - 126
11 Apr 2023
Kim Y Choi Y Cho S
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Chronic lateral ankle instability (CLAI) is treated operatively, whereas acute ligament injury is usually treated nonoperatively. Such treatments have been widely validated. Apoptosis is known to cause ligament degeneration; however, few reports have focused on the possible role of apoptosis in degeneration of ruptured lateral ankle ligaments. The aim of our study is to elucidate the apoptosis that occurs within anterior talofibular ligament (ATFL) to further validate current CLAI treatments by adducing molecular and cellular evidence.

Between March 2019 and February 2021, 50 patients were prospectively enrolled in this study. Ruptured ATFL tissues were collected from 21 CLAI patients (group C) and 17 acute ankle fracture patients (group A). Apoptotic cells were counted using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay. Western blotting for caspases 3, 7, 8, and 9 and cytochrome c, was performed to explore intrinsic and extrinsic apoptotic pathways. Immunohistochemistry was used to detect caspases 3, 7, 8, and 9 and cytochrome c, in ligament vessel endothelial cells.

More apoptotic cells were observed in group C than group A in TUNEL assay. Western blotting revealed that the apoptotic activities of group C ligaments were significantly higher than those of group A (all p < 0.001). Immunohistochemistry revealed increased expression of caspases 3, 7, 8, and 9, and cytochrome c, in group C compared to group A.

The ATFL apoptotic activities of CLAI patients were significantly higher than those of acute ankle fracture patients, as revealed biochemically and histologically. Our data further validate current CLAI treatments from a molecular and cellular perspective. Efforts should be made to reverse or prevent ATFL apoptosis in CLAI patients.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_7 | Pages 54 - 54
4 Apr 2023
Kim Y Yang H Bae H Han H
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Stem cells are known to have low levels of intracellular reactive oxygen species (ROS) and high levels of glutathione. ROS are thought to interact with several pathways that affect the transcription machinery required for stem cell differentiation, and are critical for maintaining stem cell function. In this study, we are developing a new fluorescent probe that rapidly and reversibly reacts with glutathione (GSH), the most abundant non-protein thiol in living cells that acts as an antioxidant and redox regulator.

Multipotent perivascular progenitor cells derived from human ESCs (hESC-PVPCs): Differentiated ESCs as embryoid bodies in the presence of BMP4 to induce mesoderm differentiation followed by a simple cell selection strategy using attachment of single cells onto collagen-coated dishes. Differential gene expression profiling was performed among H9 hESCs, EBs induced by BMP4 and naturally selected CD140B+CD44+ population at Day 7 (PVPCs). Colony-forming assay: GSHhigh and GSHlow PVPCs were plated on 10-cm tissue culture-treated polystyrene dishes in triplicate in growth medium and cultured for 14 days. Transwell migration assay: GSHhigh and GSHlow PVPCs at passage 4 were resuspended at 1 × 106/mL in the migration medium and seeded in the upper chamber. The following human recombinant SDF-1 and PDGF-AA proteins were used as chemoattractants in the lower compartment.

Probe-GSH conjugate shows shifts in fluorescence excitation and emission spectra that enables ratiometric measurement of GSH levels. Using these properties, stem cells can be purified by FACS-based technology according to intracellular GSH level. We are developing a protocol both for comparing GSH level in stem cell from different culture conditions and for preparing stem cells with high-GSH level . Our results reveal that GSHhigh PVPC purified by FACS show increased colony forming ability compared with that GSHlow PVPC, indicating that intracellular GSH contributes to the maintenance of stemness. Moreover, transplantation of GSHlow PVPC is more effective than that of GSHlow PVPC for cartilage regeneration in osteochondral defect.

This technique enable FACS-based sorting of stem cells according to intracellular GSH levels and thus investigation of functional role of GSH (high antioxidant capacity) in the stem cell maintenance and chondrogenic differentiation.


Bone & Joint Research
Vol. 12, Issue 1 | Pages 22 - 32
11 Jan 2023
Boschung A Faulhaber S Kiapour A Kim Y Novais EN Steppacher SD Tannast M Lerch TD

Aims

Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients.

Methods

A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method).


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_2 | Pages 52 - 52
1 Feb 2020
Lazennec J Kim Y Caron R Folinais D Pour AE
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Introduction

Most of studies on Total Hip Arthroplasty (THA) are focused on acetabular cup orientation. Even though the literature suggests that femoral anteversion and combined anteversion have a clinical impact on THA stability, there are not many reports on these parameters. Combined anteversion can be considered morphologically as the addition of anatomical acetabular and femoral anteversions (Anatomical Combined Anatomical Anteversion ACA). It is also possible to evaluate the Combined Functional Anteversion (CFA) generated by the relative functional position of femoral and acetabular implants while standing. This preliminary study is focused on the comparison of the anatomical and functional data in asymptomatic THA patients.

Material and methods

50 asymptomatic unilateral THA patients (21 short stems and 29 standard stems) have been enrolled. All patients underwent an EOS low dose evaluation in standing position.

SterEOS software was used for the 3D measurements of cup and femur orientation. Cup anatomical anteversion (CAA) was computed as the cup anteversion in axial plane perpendicular to the Anterior Pelvic Plane. Femoral anatomical anteversion (FAA) was computed as the angle between the femoral neck axis and the posterior femoral condyles in a plane perpendicular to femoral mechanical axis. Functional anteversions for the cup (CFA) and femur (FFA) were measured in the horizontal axial patient plane in standing position. Both anatomical and functional cumulative anteversions were calculated as a sum. All 3D measures were evaluated and compared for the repeatability and reproducibility

Statistical analysis used Mann-Whitney U-test considering the non-normal distribution of data and the short number of patients (<30 for each group).


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 34 - 34
1 Feb 2020
Kim Y Pour AE Lazennec J
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Purpose

Minimally invasive anterolateral approach (ALA) for total hip arthroplasty (THA) has gained popularity in recent years as better postoperative functional recovery and lower risk of postoperative dislocation are claimed. However, difficulties for femur exposure and intraoperative complications during femoral canal preparation and component placement have been reported. This study analyzes the anatomical factors likely to be related with intraoperative complications and the difficulties of access noted by the surgeons through a modified minimally invasive ALA. The aim is to define the profile for patient at risk of intraoperative complications during minimally invasive ALA.

Methods

We retrospectively included 310 consecutive patients (100 males, 210 females) who had primary unilateral THA using the same technique in all cases. The approach was performed between the tensor fascia lata and the gluteus medius and minimus, without incising or detaching muscles and tendons. Posterior translation was combined to external rotation for proximal femur exposure (Fig. 1). All patients were reviewed clinically and radiologically. For the radiological evaluation, all patients underwent pre- and postoperative standing and sitting full-body EOS acquisitions. Pelvic [Sacral slope, Pelvic incidence (PI), Anterior pelvic plane angle] and femoral parameters were measured preoperatively. We assessed all intraoperative and postoperative complications for femoral preparation and implantation. Intraoperative complications included the femoral fractures and difficulties for femoral exposure (limitations for exposure and lateralization of the proximal femur). The patients were divided into two groups: patients with or without intraoperative complications.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_1 | Pages 146 - 146
1 Feb 2020
King C Chakour K Kim Y Luu H Martell J
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Introduction

Background: Trochanteric bursitis is a common and poorly understood complication following total hip arthroplasty (THA). The purpose of this study was to evaluate the incidence of symptomatic trochanteric bursitis and the change in hip offset among THA patients before and after the introduction of robotic assistance.

Methods

Retrospective chart review of THAs performed by a single over a 3-year period between 1/5/2013 and 6/28/2016. Between 1/5/2013 and 11/11/2014 101 consecutive patients were identified that underwent manual posterior-lateral THA that utilized traditional cup positioning method based on AP Pelvis radiograph. The subsequent six-month period during a complete transition to robotic arm assistance for posterior-lateral THA was excluded to eliminate any learning curve or selection bias. Between 6/2015 and 6/2016 109 consecutive patients that underwent robotic arm-assisted. Medical records were reviewed for symptomatic trochanteric bursitis within two years of surgery. Hip offset was measured on preoperative and postoperative AP pelvis radiographs and postoperative joint reactive forces were calculated using Martell's Hip Analysis Suite.


Introduction

Limb-length discrepancy (LLD) is a common postoperative complication after total hip arthroplasty (THA). This study focuses on the correlation between patients’ perception of LLD after THA and the anatomical and functional leg length, pelvic and knee alignments and foot height. Previous publications have explored this topic in patients without significant spinal pathology or previous spine or lower extremity surgery. The objective of this work is to verify if the results are the same in case of stiff or fused spine.

Methods

170 patients with stiff spine (less than 10° L1-S1 lordosis variation between standing and sitting) were evaluated minimum 1 year after unilateral primary THA implantation using EOS® images in standing position (46/170 had previous lumbar fusion). We excluded cases with previous lower limbs surgery or frontal and sagittal spinal imbalance. 3D measures were performed to evaluate femoral and tibial length, femoral offset, pelvic obliquity, hip-knee-ankle angle (HKA), knee flexion/hyperextension angle, tibial and femoral rotation.

Axial pelvic rotation was measured as the angle between the line through the centers of the hips and the EOS x-ray beam source. The distance between middle of the tibial plafond and the ground was used to investigate the height of the foot.

For data with normal distribution, paired Student's t-test and independent sample t-test were used for analysis. Univariate logistic regression was used to determine the correlation between the perception of limb length discrepancy and different variables. Multiple logistic regression was used to investigate the correlation between the patient perception of LLD and variables found significant in the univariate analysis. Significance level was set at 0.05.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_2 | Pages 8 - 8
1 Feb 2020
Lazennec J Kim Y Folinais D Pour AE
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Introduction

Post op cup anatomical and functional orientation is a key point in THP patients regarding instability and wear. Recently literature has been focused on the consequences of the transition from standing to sitting regarding anteversion, frontal and sagittal inclination. Pelvic incidence (PI) is now considered as a key parameter for the analysis of sagittal balance and sacral slope (SS) orientation. It's influence on THP biomechanics has been suggested. Interestingly, the potential impact of this morphological angle on cup implantation during surgery and the side effects on post op functional orientation have not been studied.

Our study explores this topic from a series of standing and sitting post-op EOS images

Material and methods

310 patients (mean age 63,8, mean BMI 30,2) have been included prospectively in our current post-operative EOS protocol. All patients were operated with the same implants and technique using anterior approach in lateral decubitus.

According to previous literature, 3 groups were defined: low PI less than 45° (57 cases), high PI if more than 60° (63 cases), and standard PI in 190 other cases.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_6 | Pages 12 - 12
1 Apr 2018
Lazennec J Kim Y Pour AE
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Introduction

Few studies are published about total hip arthroplasties (THA) in Parkinson's disease as it is often considered as a contraindication for hip replacement. THA for fracture is reported as a high complication rate surgery. Regarding bone quality these cases are assimilated to elderly patients and cemented implants are generally preferred. However, due to the improved length and quality of life, we face more potential indications for joint replacement. The aim of this study is to report our experience of cementless dual mobility implants for primary THAs for osteoarthrosis and THA revisions focusing on the risks and benefits of surgery.

Material and methods

65 THA were performed in 59 patients (34 men, 25 women, mean age 73 years, 55–79). Mean latest follow-up was 8,3 years (4–14). Indications were 42 primary THA (osteoarthrosis) and 21 revisions (11 recurrent dislocation, 6 acetabular PE wear, 4 femoral loosening). Surgical approach was always antero-lateral. All patients were implanted with the same dual mobility cementless cup. The same cementless corail-type stem was used for primary THA cases. All the cemenless implants were hydroxyapatite coated. The disability caused by the disease was classified according to Hoehn and Yahr. (19 stage 1, 21 stage 2,16 stage 3)


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 50 - 50
1 Apr 2018
Kim Y Kim Y Hwang K Moon J
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Purpose

The posterolateral or posterior approach for total hip arthroplasty has the advantages of preserving the hip abductor musculature and providing good visualization during femoral preparation and component insertion. Although posterolateral approach is one of the popular approaches in hip arthroplasty, it has been reported high dislocation rate as a drawback. To compensate the drawback the repair of short external rotator of hip is thought to be important. Therefore, we investigated incidence of failed repaired short external rotator muscles, dislocation rate and time of failure between tendon to tendon and tendon to bone repair technique through prospective study more than 1 year follow up.

Materials and methods

We performed 213 hip arthroplasties in 202 patients from May 2012 to January 2015. After exclusion of 15 hips due to follow-up loss(9 hips), death(2 hips), greater trochanteric fragment displacement(3 hips) and severe contracted short external rotator(1 hip), we investigated 198 hips in 187 patients. 57 patients were male and 130 patients were female. The mean age of patient was 70.4 (32–98) years. Reattachment short external rotator with posterior capsule to postero-superior aspect of greater trochanter(tendon to bone group, 111 hips) or to the tendon(tendon to tendon group, 87 hips) was performed. Two No.26 metal wire markers were fixed at the greater trochanter tip and short external rotator tendon respectively with a distance less than 1.2cm, and the distance between two wire markers was observed at postoperative 1 day, 2 weeks, 3 months, and annually radiographs in neutral position. When the distance was more than 2.5cm or one of the wire markers was invisible, we defined them the failure of short external rotator repair. The mean follow up period was 28.8 (12–45) months.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_6 | Pages 33 - 33
1 Apr 2018
Song M Kim Y Yoo S Kang S Kwack C
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Purpose

Unicompartmental Knee Arthroplasty (UKA) has been indicated for inactive elderly patients over 60, but for young and active patients less than 60 years old, it has been regarded as a contraindication. The purpose of this study is to evaluate the usefulness of UKA performed on young Asian patients under 60 years of age by analyzing clinical outcomes, complications and survival rate.

Materials and Methods

The subjects were 82 cases, which were followed up for at least 5 years (from 5 to 12 years). Only Oxford phase III® (Biomet Orthopedics, Inc, Warsaw, USA) prosthesis was used for all cases. The clinical evaluation was done by the range of motion, Knee society score (KSS), WOMAC score. The radiographic evaluation was performed on weight bearing long-leg radiographs, AP and lateral view of the knee and skyline view of the patella. The survival rate was estimated by Kaplan-Meier survival analysis.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_1 | Pages 79 - 79
1 Jan 2018
Maranho D Davila A Novais E Kim Y Millis M
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Slipped capital femoral epiphysis (SCFE) is associated with a spectrum of proximal femoral deformity and femoroacetabular impingement (FAI). Little attention has been given, however, to the possible effect of SCFE on remaining hip growth. Our observation that some acetabula in hips with SCFE have various dysmorphology led us to evaluate the growth of the hip in our patients with SCFE. We performed an IRB-approved retrospective study of our intramural SCFE database which identified 108 hips with unilateral SCFE, at least 2 years of radiographic followup, and closure of triradiate cartilage, greater trochanter and proximal femoral physis. The contralateral non-SCFE hip was used as control. Average age at presentation was 12.3 y. 49 patients were male, 59 female.

Statistically significant differences were noted between SCFE and control hip both at both presentation and last followup(FU): Mean LCEA lower in SCFE hip at presentation by 0.97 degree; increasing to 4.36 degrees at last FU(p<0.0001). No difference noted in mean Tonnis roof angle at presentation, but at last FU SCFE hips had mean roof angle difference of 3.2 degrees higher than control(p<.0001).

In some of our SCFE patients, acetabular deformity has impacted treatment. Ongoing studies may clarify risk factors for the development of problematic acetabular deformity associated with SCFE and perhaps allow prevention of secondary acetabular deformity.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_1 | Pages 78 - 78
1 Jan 2018
Maranho D Kiapour A Kim Y Novais E
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The intra-epiphyseal growth of the proximal femur has been focus of studies because of the potential relationship with the development of slipped capital femoral epiphysis and cam deformity in femoroacetabular impingement. We aimed to evaluate the developmental pattern of the epiphyseal tubercle and extension in normal boys and girls from eight to fifteen years, without hip conditions. We performed three-dimensional (3D) analysis of pelvic computed tomographic scans of 80 subjects with suspect of appendicitis, consisting of five boys and five girls for each age, from eight to 15 years old. Images were segmented slice by slice at the level of the growth plate using biplanar orientation. The 3D-segmented epiphyses were used to measure the location and height of the tubercle, the height of the epiphyseal extension, and the epiphyseal diameter. We found that the epiphyseal tubercle was eccentrically located at the posterolateral quadrant of the physeal surface. The absolute height of the epiphyseal tubercle did not vary between ages (R2=0.04; p=0.101). The epiphyseal diameter increased with age (R2=0.74; p<0.001), making the tubercle height proportionally smaller with the epiphyseal growth (9% reduction in tubercle height normalised by the epiphyseal diameter). The normalised epiphyseal extension height significantly increased by 160% from 8 to 15 years of age. Our observation validates the hypothesis of the cupping mechanism provided by the peripheral growth of the epiphyseal extension, while the epiphyseal tubercle relatively decreases in size during the skeletal growth. Further research will be important to determine the role of these structures in the epiphyseal stability.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_5 | Pages 18 - 18
1 Mar 2017
Pun S Merz M Bowen G Hingsammer A Yen Y Kim Y Millis M
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Purpose

Periacetabular osteotomy (PAO) is a versatile acetabular reorienting procedure that is most commonly used to provide greater femoral head coverage in adolescent hip dysplasia. However, PAO can also be used to reorient the acetabulum in the opposite direction to treat femoroacetabular impingement (FAI) due to acetabular over-coverage. We describe the indications, surgical technique, and early results of reverse PAO to reduce femoral head coverage in symptomatic hips with FAI due to acetabular over-coverage.

Methods

IRB approval was obtained to retrospectively review cases of symptomatic acetabular over-coverage treated with reverse PAO and that had a minimum of two years follow-up. All hips had atypical intraoperative positioning of the acetabular fragment to uncover the lateral and anterior aspects of the femoral head, with or without anteverting the acetabulum. Prospectively collected pre- and post-operative demographics, WOMAC scores, Modified Harris Hip Score (MHHS), and radiographic measurements consisting of the lateral center edge angle (LCEA), Tönnis angle (TA), and anterior center edge angle (ACEA) were compared using student's t-test.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 35 - 35
1 Feb 2017
Jo W Lee Y Ha Y Koo K Lim Y Kwon S Kim Y
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Background

Although thigh pain is an annoying problem after total hip arthroplasty (THA), little information has been known about its natural course.

Methods

To determine the frequency, time of onset, and duration of thigh pain after cementless THA, we evaluated 240 patients (240 hips) who underwent primary THA because of femoral head osteonecrosis with the use of a single tapered stem.


Bone & Joint Research
Vol. 5, Issue 11 | Pages 544 - 551
1 Nov 2016
Kim Y Bok DH Chang H Kim SW Park MS Oh JK Kim J Kim T

Objectives

Although vertebroplasty is very effective for relieving acute pain from an osteoporotic vertebral compression fracture, not all patients who undergo vertebroplasty receive the same degree of benefit from the procedure. In order to identify the ideal candidate for vertebroplasty, pre-operative prognostic demographic or clinico-radiological factors need to be identified. The objective of this study was to identify the pre-operative prognostic factors related to the effect of vertebroplasty on acute pain control using a cohort of surgically and non-surgically managed patients.

Patients and Methods

Patients with single-level acute osteoporotic vertebral compression fracture at thoracolumbar junction (T10 to L2) were followed. If the patients were not satisfied with acute pain reduction after a three-week conservative treatment, vertebroplasty was recommended. Pain assessment was carried out at the time of diagnosis, as well as three, four, six, and 12 weeks after the diagnosis. The effect of vertebroplasty, compared with conservative treatment, on back pain (visual analogue score, VAS) was analysed with the use of analysis-of-covariance models that adjusted for pre-operative VAS scores.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 100 - 100
1 May 2016
Kim S Lim Y Kwon S Sun D Kim Y Ju S
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Introduction

The acetabular cup should be properly oriented to prevent dislocation and to reduce wear and leg length discrepancy. Despite advances in surgical techniques and instrumentation, achieving proper cup placement in total hip arthroplasty (THA) is challenging with potentially large variations of cup position and limited accuracy. We evaluated whether cup placement on anatomical location ensured original center of rotation (COR) and surgeon's experiences of THA reduced variations in acetabular component positioning.

Methods

We retrospectively reviewed 145 patients (145 hips) of unilateral THAs with normal contralateral structures of acetabulum and femoral head. All surgeries were performed using the modified posterolateral approach that preserves short external rotator muscles. All of the 145 THAs were performed by two surgeons, who were in the same teaching hospital, but had differences in surgical experience and expertise for THA. The patients were divided into two groups based upon surgical experience: (1) the highly experienced surgeon's group: who had previously performed over 1000 THAs (YSK, 101 hips), and (2) the less experienced novice's group: who had performed fewer than 30 THAs (YWL, 44 hips). Real vertical distances, from the COR to the inter-tear drop line, and the real horizontal distances, from the COR to the lateral wall of the tear drop, were measured preoperatively using picture archiving communication system (PACS) based precise method. Postoperative ones were measured and equalized by use of a magnification marker placed on preoperative plain radiographs. And cup inclination was measured directly on the AP radiographs and anteversion was calculated by trigonometric functions. The patient's mean age was 52.1 years (range, 20–86).


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_10 | Pages 25 - 25
1 May 2016
Seo J Yoo O In Y Kang B Sun D Kim Y
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Introduction

Knee joint should be aligned for reconstruction of the function in Total Knee Replacement(TKR). Although a surgeon try to correct the alignment of a knee joint, sometimes varus/valgus alignment has been tried in order to reconstruct function of knee joint. As a result, the varus or valgus alignment affects to ligaments and soft tissue, and the contact condition is changed between femoral component and tibial insert. One of important factor, wear characteristics of an implant can be changed due to the contact condition. In this study, we performed static contact tests from extension to flexion in varus and valgus to define the effect to contact condition when the alignment is varus or valgus.

Methods

LOSPA TKR femoral component #6 and Tibial insert #5 manufactured by Corentec Co., Ltd. were used as test specimens. The tests have performed with adapting ASTM F2777–10 ‘Standard Test Method for Evaluating Knee Bearing (Tibial Insert) Endurance and Deformation under High Flexion’. The test set like as Fig. 1. The load is applied at 7:3 ratio of lateral-medial by adapting gait analysis. The 5° of jig is used to compare the result in neutral, varus and valgus. The fuji films were used in tests were scanned, and the results were analyzed the compressed area and contact stress as angles of flexion in neutral stance and varus/valgus from scanning. The tests were performed 5 times per each for a reliability.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_8 | Pages 99 - 99
1 May 2016
Kim J Yoo O Seo J Jang Y Kim J Sun D Kim Y
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Introduction

A stem extension improves fixation stability of a tibial component. We need caution not to contact the tibial cortex with an offset adaptor. A symmetric tibial stem design often requires the component's re-positioning with negative effects. Therefore, the objective of this study was to validate clinical efficacy of a tibial baseplate with asymmetric stemmed position (TB-ASP) using aligning outlier rate. We hypothesized that TB-ASP design will be better aligned without unessential offset adaptor than a tibial baseplate with symmetric stemmed position (TB-SSP).

Methods

TB-ASP was designed based on the anthropometric standard model (58 female cadavers, 54.7±11.4 years)(Figure 1.). To validate the stem position, 3D bone models of 20 OA patients (71.8±7.2 years) was reconstructed. All virtual surgery has done by one surgeon with consistent surgical procedure for the analysis criteria.

An analysis of TB-ASP's aligning outlier was proceeded by following steps; 1) aligning tibial baseplate to the line from medial 1/3 tuberosity to the center of PCL, 2) selecting tibial baseplate's size for maximal bone coverage without problematic overhang, 3) trying to displace tibial baseplate and stem extension(120mm long) not to contact tibial cortex. A case invading tibial cortex was considered to be an outlier. The ratio using offset adaptor was compared to those of TB-SSP. Statistical analysis was performed using paired t-test.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_9 | Pages 2 - 2
1 May 2016
Lim Y Kwon S Sun D Kim S Kim J Choi S Kim Y
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Introduction

3-D Printing with direct metal tooling (DMT) technology was innovatively introduced in the field of surface treatment of prosthesis to improve, moreover to overcome the problems of plasma spray, hopefully resulting in opening the possibility of another page of coating technology. We presumed such modification on the surface of Co-Cr alloy by DMT would improve the ability of Co-Cr alloys to osseointegrate.

Method

We compared the in vitro and in vivo ability of cells to adhere to DMT coated Co-Cr alloy to that of two different types of surface modifications: machined and plasma spray(TPS). We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines of human were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and avb3 integrin. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the MAO group increased in comparison to those in the machined and grit-blasted groups.