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Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 29 - 29
1 Apr 2018
Kim S Han S Rhyu K Yoo J Oh K Lim S Suh D Yoo J Lee K
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Introduction

In recent years, there has been an increase in hip joint replacement surgery using short bone-preserving femoral stem. However, there are very limited data on postoperative periprosthetic fractures after cementless fixation of these stem although the periprosthetic fracture is becoming a major concern following hip replacement surgery. The purpose of this study is to determine incidence of postoperative periprosthetic femoral fractures following hip arthroplasty using bone preserving short stem in a large multi-center series.

Materials & Methods

We retrospectively reviewed 897 patients (1089 hips) who underwent primary total hip arthroplasty (THA) or bipolar hemiarthroplasty (BHA) during the same interval (2011–2016) in which any other cementless, short bone-preserving femoral stem was used at 7 institutions. During the study, 1008 THAs were performed and 81 BHAs were performed using 4 different short femoral prostheses. Average age was 57.4 years (range, 18 – 97 years) with male ratio of 49.7% (541/1089). Postoperative mean follow-up period was 1.9 years (range, 0.2 – 7.9 years).


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_5 | Pages 63 - 63
1 Apr 2018
Rhyu K Cho Y Chun Y
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Background

Load transfer to the bone is believed to be more physiological around the short stem in total hip arthroplasty (THA). However, we found unusual bony remodeling around the shortened tapered femoral stem.

Methods

Among 121 consecutive THA using the same shortened tapered stem, 25 hips were excluded because the lateral cortex was already disturbed by previous surgery on the proximal femur. Sixteen hips were also excluded either because direct measurement was unavailable due to improperly taken final radiographs (n=9) or the patient was lost to follow-up (n=7).80 THAs were finally enrolled. Radiographic measurements were made using anteroposterior (AP) radiographs taken immediately and at 2 years after surgery. The thickness of the lateral cortex at the level of the distal end of the coated surface and at 10, 20, 30, and 40 mm proximal to it were measured. Variables for detecting the causative factors were age, gender, BMI, proximal femoral geometry, whether the surgery was done to dominant side, diagnosis leading to surgery, size and offset of the stem, articulation, alignments and operative time.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_4 | Pages 115 - 115
1 Feb 2017
Chun Y Cho Y Lee C Bae C Rhyu K
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Purpose

This study was performed to evaluate clinical and radiographic outcomes of Hip Resurfacing Arthroplasty for treatment of haemophilic hip arthropathy.

Material & Method

Between 2002 and 2013, 17 cases of hip resurfacing arthroplasties were performed in 16 haemophilic patients (13 cases of haemophilia A, 2 cases of haemophilia B, 2 cases of von Willebrand disease). The average age of the patients was 32.5(range: 18∼52) years. The average follow up period from the operation was 6.3 (range: 2∼13) years. In this study, the subjects that completed follow-up were composed of 5 cases composed of patients who were treated with Conserve plus® hip resurfacing system, 5 cases composed of patients who were treated with Durom® hip resurfacing system, 4 cases who were treated with ASR® hip resurfacing system, and 3 cases who were treated with Birmingham® hip resurfacing system. The Modified Harris hip score, the range of motion of the hip joint, perioperative coagulation factor requirements and complications associated with bleeding were evaluated as part of the clinical assessment. For the radiographic assessment, fixation of component, presence of femoral neck fracture, osteolysis, loosening and other complications were evaluated.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 83 - 83
1 May 2016
Chun Y Rhyu K Baek J Oh K Lee J Cho Y
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Purpose

The purpose of this study was to evaluate and compare the clinical, radiological outcomes of the group of patients with distal femoral cortical hypertrophy (DFCH) and without DFCH after hip arthroplasty using a cementless double tapered femoral stem and to analyze a correlation between patients factors and DFCH.

Materials and Methods

Four hundreds four patients (437 hips) who underwent total hip arthroplasty (n = 293) or hemiarthroplasty (n = 144) using a Accolade TMZF femoral stem between Jun 2006 and March 2012 and were follow up period more than 24 months after surgery were enrolled in this study. They were divided into 2 groups, the one group (n = 27) included patients with DFCH, and the other group (n = 410) included patients without DFCH. The mean follow up period was 54.5 months (range, 24 to 85 months) and 56.2 months (range, 24 to 92 months) for patients with DFCH and without DFCH.


Orthopaedic Proceedings
Vol. 93-B, Issue SUPP_IV | Pages 449 - 449
1 Nov 2011
Cho Y Kim K Chun Y Rhyu K Song J Yoo M
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We wanted to evaluate the clinical and radiological results of acetabular revision using the acetabular reinforcement ring and allograft impaction in patients with severe acetabular bony defect.

41 hips revision arthroplasty using reinforcement ring were performed between April 1997 and October 2005 and were followed up for more than two years. The cause of primary arthroplasty was AVN in 18 cases, secondary osteoarthritis (OA) in 17 cases, fracture in cases and primary OA in 1 case. The cause of revision arthroplasty was acetabular cup loosening in 20 cases, massive osteolysis in 14 cases, infection in 4 cases, liner dissociation in 2 cases, and recurrent dislocation in 1 case. The average period between primary and revision arthroplasty was 11.4 years (range 0.6 to 29.1 years). Acetabular defects were classified based on the AAOS classification and Paprosky classification system. All were treated with autografts or allografts. Muller ring was used in 18 cases, Burch-Schneider ring was used in 14 cases, and Ganz ring in 9 cases. Clinical evaluations were performed according to the Harris hip score (HHS), and the radiographic results were evaluated by progression of acetabular component loosening, union of bone grafts, periacetabular osteolysis, and migration of the hip center.

The mean preoperative Harris hip score of 64.9 was improved to 91.8 points at the latest follow-up. There were 39 cases of type 3 defect, 2 cases of type 4 defect according to the AAOS classification and 8 cases of type 2B defect, 3 cases of type 2C defect, 28 cases of type 3A defect, and 2 cases of type 3B defect according to Paprosky classification.

Radiographically, the bone grafts were well united except one case. The mean preoperative hip center of rotation which was vertically 32.3mm, horizontally 33.2 mm migrated to vertically 26 mm, horizontally 33.2 mm postoperatively and it was statistically significant.

The mean preoperative abductor lever arm of 41.7 mm changed to 45 mm postoperatively which was statistically insignificant. However the mean preoperatiave body lever arm of 89.4 mm changed to 96.9 mm postoperatively which was statistically significant. Postoperative complications were cup loosening in 1 case, dislocation in 2 cases, and recurrence of deep infection in 1 case.

Clinically and radiographically, acetabular reconstruction using reinforcement ring showed very promising short term result. We conclude that reinforcement ring can provide stable support for grafted bone in severe bone defect. But meticulous surgical technique to get initial firm stability of ring and optimal indication in mandactory for the successful result.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 145 - 145
1 Mar 2010
Chun Y Yoo M Cho Y Kim K Rhyu K
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The ultimate goal for treatment of osteonecrosis of femoral head (ONFH) is preserving the femoral head. We have tried to manage the patient who received failed joint preserving procedures with resurfacing arthroplasty if they fit the indicati385on. In this brief review, we wanted to clarify the role and technical concern of resurfacing arthroplasty as a salvage procedure after failed joint preserving operations for ONFH.

Among 556 hips underwent resurfacing arthroplasty from September 1998 to October 2007, sixteen resurfacing arthroplasties (13 patients) were performed after failed joint preserving procedures for ONFH. Mean age at the operation was 39 years old. Seven vascularized fibular grafts, 3 multiple drillings, 3 core decompressions and 3 combined procedures were performed as initial operations. Mean duration from the index operation and resurfacing was 95 months. Mean follow up was 14 months. The patients were clinically evaluated with the Harris hip score, hip or thigh pain, and range of motion. As a radiological evaluation, we measured positions of the acetabular cup and femoral stem, radiographic changes at the neck and complications. The Harris hip score increased from 69.2 preoperatively to 89.5 at the final visit. Hip range of motions other than sagittal directions significantly improved after the operation. No patient complained of limb length discrepancy. One patient complained of unexplained hip pain, and another patient had trochanteric pain. Other than those two cases, all patients regained their pre-morbid activity level uneventfully. Radiologically, eleven femoral stems in anteroposteior and lateral radiographs were exactly aligned along the previous operative tracts. However, there were no clinical complications related to the position of femoral component. The only case that the acetabular cup was implanted in high inclination (60 degrees) experienced sustained unexplained hip pain. There was no another complications.

Our experience suggests that even for the case of failed hip preserving procedures in ONFH, resurfacing arthroplasty can play a successful role as a salvage operation. Furthermore, this can be an excellent alternative between joint preserving procedures and conventional THA.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 145 - 145
1 Mar 2010
Yoo M Cho Y Kim K Chun Y Rhyu K Roh J Kang C
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The purpose of this study is to evaluate short to mid-term clinical and radiological results of metal on metal resurfacing arthroplasty in osteonecrosis of the femoral head (ONFH).

185 hips of 169 patients who underwent metal on metal resurfacing arthroplasty using Birmingham Hip Resurfacing system (Midland Medical Technololgies, Birmingham, UK) between December 1998 and May 2005 were available for this study and all cases were followed up over 3 years. All preoperative diagnoses were ONFH. The extents of necrotic area were analyzed by preoperative MRI scanning. Their mean age at the time of operation was 37.7(range, 16–67) years old and mean period of follow-up was 88(range, 36–113) months. For the clinical assessments, Harris hip scores, UCLA activity scores, pain and ROM were evaluated. Radiological changes such as radiolucencies around the stem, impingement sign, neck narrowing, osteolysis around head and neck junction, loosening of implants, heterotopic ossifications were evaluated in the serial antero-posterior, translateral radiographs of the hip joint.

Preoperative necrotic area was average 42.7(range, 11.5–60) %. Clinically, the average Harris hip score was improved from 85.2 points to 97.1 points at final follow-up. Average UCLA activity scores at the last follow-up was 8.8 and almost of the patients showed high activity and returned to their original job. ROM were very satisfactory. Radiologically, the mean inclination of acetabular component was 48.0°. There were no radiolucent lines around the acetabular components, but 3 cases showed radiolucent lines around the stem of femoral components. Osteolytic lesions were noticed in 10 cases around head-neck junction. Nine hips had impingement signs around the head-neck junction. There was no case which showed evidence of stress shielding. Moderate neck narrowing were shown in 3 cases. There were 6 cases of heterotopic ossification. One hip had a revision surgery to a total hip arthroplasty using big metal ball because of loosening of acetabular component. There was no patient complained limb length discrepancy and no infection, dislocation, thigh pain.

The midterm performance of metal on metal resurfacing arthroplasty in ONFH was very excellent in the aspects of pain relief, ROM of hip joints, rehabilitation and return to preoperative activity and minimization of common complications of conventional total hip arthroplasty. There was no mechanical failure related to the osteonecrosis and we can conclude that performing resurfacing arthorplasty in osteonecrosis less than 50% of extent can be justified. However, performing resurfacing arthroplasties in osteonecrosis of femoral heads needs meticulous surgical techniques and longer learning curve to prevent early failure. Even though our midterm follow-up study revealed excellent results, more long-term follow-up studies are mandatory to determine the survivorship and to verify the problems related to the increased serum metal ion and metal ion toxicity after resurfacing arthroplasty.


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.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 140 - 140
1 Mar 2010
Yoo M Cho Y Kim K Chun Y Rhyu K Roh J Kim J
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The purpose of this study is to analyze clinical and radiological results of total hip arthroplasty using the 3rd generation ceramic on ceramic articular surface.

Between July 1999 and May 2005, 339 hips of 250 patients had primary cementless total hip arthroplasty with the 3rd generation ceramic on ceramic bearing implants. And 325 hips of 236 patients were followed up over 3 years. Male were 168 patients(237 hips) and female were 68 patients(88 hips). The mean age at the time of operation was 47.3(range, 25~76) years old and the mean follow up period was 62.4(range, 36~107.6) months. The preoperative diagnoses were osteonecrosis of the femoral head (ONFH) in 250 hips, secondary osteoarthritis in 55 hips(dysplasia in 35, infection sequalae in 12, LCP in 2, CDH in 2), hemophilic arthropathy in 9 hips, ankylosing spondylitis in 7 hips etc.

We used Bicontact system(Aesculap, Germany) in 65 hips, Secur-FitTM(Stryker Howmedica Osteonics, USA) in 206 hips, Trilogy ABTM (Zimmer, USA) in 54 hips. Clinically, Harris Hip Score, thigh pain, squeaking and other complications were evaluated. Radiologically, the serial radiographs were analyzed.

Clinically, the Harris hip score was improved from preoperative 66.0(19~91) to 96.2(58~100) at the last follow-up. Radiologically, there was no loosening of implants and visible wear and osteolysis. Heterotopic ossifications were noted in 5 cases. In complications, there was dislocation in one case, periprosthetic fracture in 2 cases and thigh pain in 9 cases. Intermittent squeaking sound has occurred in 8 cases(2.5%). Among these, one case of loud squeaking which happened after fall down had revision surgery. There was no infection and fracture of ceramic implant.

Our midterm results of THA with the 3rd generation ceramic bearing system were very satisfactory and demonstrated that the 3rd generation ceramic bearings remain as an excellent bearing choice because of their superior wear characteristics. However, the results of this study suggests that the squeaking would be one of strong potential risk factors for failure of ceramic on ceramic total hip arthroplasty and we must be very cautious to prevent squeaking.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 137 - 137
1 Mar 2010
Kang J Park E Jung Y Cho M Song J Lee J Chang J Rhyu K
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Although the clinical manifestation of ONFH is well summarized as forms of various stages, its etiology, natural history or epidemiology has not been clearly elucidated yet. With this study, we wanted to find out the estimated annual incidence, epidemiologic characteristics and the effect of known risk factors of ONFH. Therefore we can understand the disease better to provide optimal management to the patients.

Among 133 189 patients who diagnosed as osteonecrosis of femoral head (ONFH) in database of national health insurance system in Korea from 2002 to 2006, three hundreds an eighty-two samples were randomly extracted with 5% error range in 95% confidence interval. With a structured worksheet, medical records and radiographs of each sample were reviewed at corresponding clinic or hospital by authors and trained orthopedic surgeons. With these data, we calculated the prevalence and associated risk factors.

The mean number of annual requests was 23 466. Among 382 samples, two hundreds and seventy-four were confirmed to have ONFH. Diagnostic accuracy was 71.7 %. Diagnosis was more accurate when the patient was male or hospitalized. After the logistic regression analysis, calculated diagnostic accuracy during 2002 and 2006 was 60.3% (51 823/85 987). The annual predicted number of cases of ONFH during this period was 14 103. It corresponds to 28.91 patients per 100 000 populations. Alcohol abuse was noted in 45% and 22% was related to use of steroid. 37% showed bilateral involvement. Bone graft procedures in any kind was the most frequently performed joint preserving procedure.

With this, the first epidemiologic study for ONFH in Korea, we estimated nationwide annual prevalence of ONFH as 28.91 per 100,000 populations during 2002 and 2006. There is an absolute male predominance. Alcohol abuse is the most frequent risk factors. We believe that this result can serve as a baseline data for understanding the epidemiology, clinical characteristics and treatment of ONFH.