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Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_2 | Pages 51 - 51
1 Jan 2016
Cho YJ Chun YS Rhyu KH Hur D Liang H
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Purpose

Short metaphyseal fitting femoral stems convey stress to proximal femur and have no distal fixation. They have advantages in that there is no thigh pain and no bone loss due to stress shielding, but there is a concern for weakened fixation. So the authors evaluated whether short metaphyseal fitting femoral stems, which have only metaphyseal and no diaphyseal fixation, can acquire sufficient stability.

Materials & methods

39 cases of 36 patients who undervent uncemented total hip arthroplasty with DePuy ProximaTM (Johnson & Johnson orthopaedics, New Milton, UK) short metaphyseal fitting femoral stems from August 2009 to September 2011 were retrospectively evaluated. There were 19 male and 20 female cases. The mean follow-up period was 35.8(21.8∼49.2) months. Harris hip scores, WOMAC scores, UCLA scores, and presence of femoral pain were evaluated to assess clinical outcome. Femoral radiolucency in coronal and sagittal views of the hip, femoral stem loosening, and displacement was measured to evaluate radiological outcome. Distance between femoral stem and cortical bone was also measured to assess the relationship with radiolucency and loosening according to degree of contact.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_1 | Pages 76 - 76
1 Jan 2016
Cho YJ Hur D Chun YS Rhyu KH
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Purpose

Cementless cup with structural allograft is one of option for acetabular revision in the cases which has severe bone loss. This study was performed to verify that the structural allograft with cementless cup could be one of good options for revision of acetabular cup with severe bone defect and to verify that the allograft resorption affect the stability of cementless acetabular cup.

Materials and Methods

We reviewed 25 cases of 25 patients who underwent acetabular cup rvision using cementless porous coated hemispherical cup with structural allograft from May 1992 to July 2011 July 2011. There were nine males and sixteen females with an average age of 50.0 years. The average follow-up period was 76.7(28∼212) months. The clinical evaluation was performed using Harris Hip Score(HHS) and UCLA activity score. Radiologically, the degree of resorption of grafted bone, incorporation of allograft bone with normal bone, osteolysis and cup loosening were evaluated.


The Bone & Joint Journal
Vol. 96-B, Issue 10 | Pages 1319 - 1324
1 Oct 2014
Oh JS Youm YS Cho SD Choi SW Cho YJ

Previous studies support the important role of vascular endothelial growth factor (VEGF) and syndecan-4 in the pathogenesis of osteoarthritis (OA). Both VEGF and syndecan-4 are expressed by chondrocytes and both are involved in the regulation of matrix metalloproteinase-3, resulting in the activation of aggrecanase II (ADAMTS-5), which is essential in the pathogenesis of OA. However, the relationship between VEGF and syndecan-4 has not been established. As a pilot study, we assayed the expression of VEGF and syndecan-4 in cartilage samples and cultured chondrocytes from osteoarthritic knee joints and analysed the relationship between these two factors.

Specimens were collected from 21 female patients (29 knees) who underwent total knee replacement due to severe medial OA of the knee (Kellgren–Lawrence grade 4). Articular cartilage samples, obtained from bone and cartilage excised during surgery, were analysed and used for chondrocyte culture. We found that the levels of expression of VEGF and syndecan-4 mRNA did not differ significantly between medial femoral cartilage with severe degenerative changes and lateral femoral cartilage that appeared grossly normal (p = 0.443 and 0.622, respectively). Likewise, the levels of expression of VEGF and syndecan-4 mRNA were similar in cultured chondrocytes from medial and lateral femoral cartilage. The levels of expression of VEGF and syndecan-4 mRNAs were significantly and positively correlated in cartilage explant (r = 0.601, p = 0.003) but not in cultured chondrocytes. These results suggest that there is a close relationship between VEGF and syndecan-4 in the cartilage of patients with OA. Further studies are needed to determine the exact pathway by which these two factors interact in the pathogenesis of OA.

Cite this article: Bone Joint J 2014;96-B:1319–24.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 36 - 36
1 Mar 2013
Cho YJ Lee J Kwak S Chun YS Rhyu KH Won YY Yoo M
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Purpose

There are some concerns about doing hip resurfacing arthroplasty in ONFH due to bone defect which can cause mechanical weakness of femoral component and highly active young age of patients which can cause high wear rate and failure rate. The purpose of this study is to verify the HRA is safe procedure in ONFH in the aspect of mechanical and biological issue.

Materials and Methods

Between December 1998 and May 2005, 185 hips of 169 patients underwent MoM HRA using Birmingham Hip Resurfacing System® at single center. 166 hips (26 hips of female, 140 hips of male) of 144 patients have been reviewed for at least 7 years after MoM HRA. Mean follow-up period was 101.8 (84–178) months. Their mean age at the time of operation was 37.7(16–67) years old. Clinically, Harris hip scores (HHS), UCLA activity scores and range of motion were evaluated. Radiologically, the extent of necrotic area in preoperative MRI and radiolucency around implants, narrowing of retained neck, impingement, stress shielding, and heterotopic ossification were evaluated in the serial anteroposterior and groin lateral radiographs of hip. Complications were defined as joint dislocation, infection, implant loosening, femoral neck fracture and pseudotumor. Failure was defined as revision arthroplasty due to the complications.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 147 - 147
1 Mar 2013
Cho YJ Lee J Chun YS Rhyu KH Kwak S Won YY Yoo M
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Purpose

In general, the amount and rate of linear wear are associated with femoral head size in the conventional UHMWPE acetabular liner. The smaller the femoral head, the higher the linear wear rate. The aim of this study is to verify the relationship between wear rate and femoral head size and the polyethylene cup thickness.

Materials and Methods

We conducted a retrospective review of all patients who had undergone primary cementless total hip arthroplasty using the conventional UHMWPE (HGP2) acetabular liner between July 1992 and December 2002. 128 hips (34 hips of female, 94 hips of male) of 64 patients who had 28 mm femoral head with different polyethylene acetabular linear thickness and 102 hips (41 hips of female, 61 hips of male) of 81 patients with 22 mm femoral head were included. Patients were assessed clinically and radiographically at postop 6 weeks, 3 months, 6 months and annually thereafter. Clinical assessment was performed using Harris Hip Score. Radiographic analysis included measurement of acetabular component position, polyethylene wear using a validated radiographic technique (Dorr method). Their mean age at the time of operation was 45.3 (24–81) years old and mean follow-up period was 10.8 (96–144 months) years.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_15 | Pages 113 - 113
1 Mar 2013
Cho YJ Lee J Chun YS Rhyu KH Kwak S Ji H Won YY Yoo M
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Purpose

To evaluate the radiological changes after metal on metal resurfacing arthroplasty.

Materials and Methods

Between December 1998 and August 2004, 166 hips in 150 patients who underwent metal resurfacing arthroplasty and followed up more than 4 years. Their mean age at the time of operation was 37.3 years(range, 15–68 years) and mean period of follow-up was 6.1 years(range, 48–95 months). The cause of arthroplasty included 115 avascular necrosis, 43 osteoarthritis, 7 ankylosing spondylitis, 1 haemophilic arthropathy. All patients had anteroposterior, translateral radiographs of the hip made preoperatively and each follow-up visit, and we analyzed radiographic findings such as radiolucencies or impingement signs around implant, neck narrowing and heterotopic ossification.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXV | Pages 23 - 23
1 Jun 2012
Cho YJ Kwak SJ Chun YS Rhyu KH Lee SM Yoo MC
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Purpose

To evaluate the clinical and radiologic midterm results of rotational acetabular osteotomy (RAO) in incongruent hip joints.

Material and Methods

A consecutive series of 15 hips in 14 patients who underwent RAO in incongruent hip joint were evaluated at an average follow-up of 52.3 months (range from 36 to 101 months). The average age at operation was 27 years (range from 12 to 38 years) old. The preoperative diagnoses were developmental dysplasia in 4 hips, sequelae of Legg-Calvé-Perthes disease in 8 hips, and multiple epiphyseal dysplasia in 3 hips. The RAO procedures were combined with a femoral valgus oseotomy in 10 hips, advance osteotomy of greater trochanter in 4 hips, derotational osteotomy in 2 hips. Clinically, Harris hip score, range of motion, leg length discrepancy(LLD) and hip joint pain were evaluated. Radiological changes of anterior and lateral center-edge(CE) angle, acetabular roof angle, acetabular head index(AHI), ratio of body weight moment arm to abductor moment arm, and a progression of osteoarthritis were analyzed.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXV | Pages 24 - 24
1 Jun 2012
Cho YJ Kwak SJ Chun YS Rhyu KH Nam DC Yoo MC
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Purpose

The ultimate goal in total hip arthroplasty is not only to relieve the pain but also to restore original hip joint biomechanics. The average femoral neck-shaft angle(FNSA) in Korean tend to have more varus pattern. Since most of conventional femoral stems have relatively high, single, fixed neck shaft angle, it's not easy to restore vertical and horizontal offset exactly especially in Korean people. This study demonstrates the advantages of dual offset(especially high-offset) stem for restoring original biomechanics of hip joint during the total hip arthroplasty in Korean.

Materials and Methods

180 hips of 155 patients who underwent total hip arthroplasty using one of the standard(132°) or extended(127°) offset Accolade cementless stems were evaluated retrospectively. Offset of stem was chosen according to the patient's own FNSA in preoperative templating. In a morphometric study, neck-shaft angle of proximal femur, vertical offset and horizontal offset, abductor moment arm were measured on preoperative and postoperative both hip AP radiographs and the differences and correlation of each parameters, between operated hip and original non-operated hip which had no deformity (preoperative ipsilateral or postoperative contralateral hip), were analyzed.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_VIII | Pages 38 - 38
1 Mar 2012
Chun YS Yoo MC Cho YJ Kim KI Rhyu KH
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Introduction

Hip resurfacing arthroplasty (HRA) with metal-on-metal bearing is currently emerging as a major evolution of hip arthroplasty. It could be an alternative to total hip arthroplasty. HRA also may allow young patients to perform high sports activities. It preserves proximal femoral bone stock and keeps the medullary canal intact. A large diameter of the femoral head provides wider range of the hip motion. Incidence of dislocation is very low. Most of HRA have been reported for young patients with stage of osteoarthritis. But, reports of HRA for osteonecrosis of the femoral head (ONFH) are rare and the outcomes are uncertain.

Methods

This study was performed to introduce our indication and technique of HRA for the patients with ONFH and to assess the outcomes after a minimum 5-year follow up. After the biomechanical study, we set our own indications for HRA as follows: when the size of a lesion was less than 50% of the entire head and the rim at the head-neck junction was intact at least to a 5 mm above from the head-neck junction. From December 1998 to July 2004; 157 hips (139 patients) underwent HRA under the diagnosis of ONFH. Their mean age was 37 years. One hundred and fourteen hips were in men and 25 hips were in women. The average follow-up period was 88 months (range, 60 to 128 months). Clinical outcomes were evaluated with Harris Hip Scores, hip or thigh pain, limb length discrepancy, and range of motion. As a radiological evaluation, the preoperative size and staging of the lesion, patterns of bone remodeling, and complications such as femoral neck fracture, neck narrowing, loosening, and osteolysis were analyzed.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_II | Pages 272 - 273
1 May 2010
Kim KI Cho YJ Chun YS Rhyu KH Yoo MC
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Introduction: The aim of this study is to analyze the mid-term result of cementless total hip arthroplasty(THA) performed in hemophilic arthropathy of the hip.

Materials and Methods: Of the 22 hips (19 patients) that underwent cementless THA under the diagnosis of hemophilic arthropathy from Aug. 1995 to June. 2002, 20 hips (17 patients) that can be followed more than five years were enrolled. The average age was 35.1 years. All of the patients had type A hemophilia. There was no patient who had antibody for factors or positive test for HIV. The mean follow-up period was 99.6 (61–147) months. As a clinical assessment, we evaluated Harris hip score, hip range of motion, amount of transfusion and factor replacement, perioperative bleeding and the problems associated with the use of coagulation factors and the bleeding itself after the surgery. As a radiological assessment, we evaluated the stability and fixation of the components, various bone responses around the implants and complications such as loosening and osteolysis.

Results: The average Harris hip score improved from 62.4 before surgery to 93.6 at the final follow-up. The hip range of motions in all plane significantly increased after the operation. During and after the surgery, an average of 3.2 units of packed RBC was transfused and an average of 46000 units of coagulation factors was injected. All patient obtained significant pain relief and improvement walking ability after the operation. The episode of re-bleeding was observed in four cases. In one of them, severe osteolysis around the pelvis and femoral stem was noted due to a huge pseudotumor. Radiographically, all components except one cup showed stable fixation at the final follow-up. The osteolysis was noted in three cups and three stems each. As a re-operation, one morsellized bone graft for osteolysis and one cup revision for a loosened cup were performed at 134 and 40 months after the index operation. One case of pseudotumor is waiting for the surgery.

Conclusion: Unlike the worrisome results of cemented THA, meticulously performed cementless THA for the moderate or severe hemophilic arthropathy is safe and greatly effective in reducing the pain, increasing the range of hip motion and improving the walking ability. However, special attention should be paid to the possible complications associated with re-bleeding such as pseudotumor around the hip. To obtain best result multidisciplinary team approach is mandatory.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 109 - 110
1 Mar 2010
Rhyu K Yoo M Cho YJ Kim K Chun YS
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For radiographic assessment of THA, we must estimate a 3-D structure with 2-D images. Basically, it has been good. But even after a successful surgery, sometimes we encountered an undersized stem in radiograph. Interestingly, it was more frequent after we introduced surgical robot for primary THA. It sometimes brought a huge dilemma during planning and evaluating the surgery. We performed this study to elucidate the cause of this problem.

We used image data of 30 consecutive THAs using ROBODOC (ISS, USA). The measurement was made with the built-in tool in the Orthodoc, which is for the CT-based preoperative planning, and digital imaging system (PiView, Infinitt, Korea). We measured femoral anteversion, tilting angle at corresponding level, the longest and shortest diameters of femoral canal and their ratio. Also we measured anteversion and alignment of the stem. The canal filling of the stem was measured in projected images with CT and postoperative radiographs.

The mean femoral anteversion was 21.1±10.2°. The canal tiling angle was 39.3±7.9°(p< 0.01). The long and short diameters were 19.3±2.6° and 14.3±1.8°. The mean ratio between them was 0.8±0.08°. Canal filling at AP and lateral dimensions were 88.25±9.8% and 85.7±6.9%. In postoperative radiographs, they were 85.4±7.3%(p=0.05) and 88.0±6.1%(p=0.06).

This result suggests that the femoral canal at this particular or more distal level is elliptically shaped constantly. It tilts (in axial plane) to the same direction but not to the same degrees with femoral anteversion. Because of this tilt, relatively well-fixed round femoral stem can be considered as undersized in plane radiograph. Therefore, rather than using two plain radiographs alone for postoperative evaluation, adding postoperative CT may provide appropriate accuracy for assessment. And surgeon should keep in mind this axial tilt during planning and evaluating a robotic THA, especially not to remove too much healthy cortical bones to obtain full distal filling.