Joon Soon Kang

Accuracy of Measurement of Polyethylene Wear with Use of Radiographs of Total Hip Replacements

BACKGROUND Although a number of methods are used to estimate polyethylene liner wear from radiographs of total hip replacements, there is no consensus with regard to the accuracy of these methods. The purpose of this study was to compare the accuracy of several such measurement methods with use of both laboratory radiographs and routine clinical radiographs. METHODS A phantom apparatus was designed to simulate random values of three-dimensional wear, with varying degrees of cup abduction and anteversion, and to obtain anteroposterior and cross-table lateral radiographs with each value. Wear was measured with use of the Charnley duoradiographic method, the Livermore method, and the method described by Dorr and Wan, as well as with use of PolyWare and Hip32 software packages, both with and without three-dimensional measurements. Clinical wear was measured from conventional radiographs made prior to revision surgery in fourteen patients and was compared with wear measured directly from the retrieved liners with use of a coordinate measuring machine. RESULTS With laboratory radiographs, median errors were 0.1 mm with the Livermore method and both computerized methods, 0.23 mm with the Charnley method, and 1.7 mm with the method of Dorr and Wan. Maximum errors were between 0.6 mm (Livermore) and 4.3 mm (Dorr and Wan). In contrast, with use of clinical radiographs, median errors ranged between 0.2 mm (Hip32) and 0.6 mm (Dorr and Wan). Maximum errors ranged between 1.8 mm (Dorr and Wan) and 2.5 mm (Livermore). CONCLUSIONS With laboratory radiographs, computerized methods of polyethylene wear measurement offered distinctly greater accuracy than did manual methods; however, with clinical radiographs, they offered only slightly better accuracy. Although the increased accuracy of computerized methods may be necessary in research settings, manual methods provided sufficient accuracy for routine clinical assessment of wear.

Variations of Clonal Marrow Stem Cell Lines Established from Human Bone Marrow in Surface Epitopes, Differentiation Potential, Gene Expression, and Cytokine Secretion

Bone marrow has been considered to contain many different types of progenitor or stem cells. This study aims to establish a new strategy that provides for the rapid establishment of human clonal marrow stem cell (hcMSC) lines with a relatively small amount of bone marrow aspirate and to characterize newly generated hcMSC lines for their cell phenotype, differentiation potential, lineage-specific gene expression, and cytokine secretion. Human cMSC lines were generated with human bone marrow aspirates using a new protocol, called the subfractionation culturing method. The newly established hcMSC lines were analyzed for their cell surface epitopes by fluorescence-activated cell sorting (FACS), differentiation potential by in vitro differentiation assays, lineage-specific gene expression by RT-PCR, and cytokine secretion by enzyme-linked immunoassay (ELISA). The overall profile of the cell-surface epitopes of the newly established hcMSC lines was similar to those of the known MSCs. These hcMSC lines were capable of differentiating into multilineages with some differences in differentiation capability. In addition, these hcMSC lines secrete high levels of transforming growth factor-beta1 (TGF-beta1), leukemia inhibitory factor (LIF), TGF-alpha, and interleukein-10 (IL-10), again with some variation in each cell line. The newly designed protocol may be an efficient method to establish hcMSC lines rapidly with a relatively small amount of bone marrow sample, and these newly established hcMSC lines possess stem cell characteristics and exhibit some differences in cell-surface epitopes, differentiation potential, lineage-specific gene expression, and cytokine secretion.

Prevalence of Osteonecrosis of the Femoral Head: A Nationwide Epidemiologic Analysis in Korea

This study was performed to estimate the prevalence of osteonecrosis of the femoral head in Korea. Using medical claims data from the Korean National Health Insurance Corporation, all individuals treated under a diagnosis of osteonecrosis of the femoral head were identified for each year from 2002 to 2006. Among them, the number of true cases was estimated using a randomly collected validation sample of 382 patients for which the actual diagnosis was investigated by authors. The estimated yearly prevalence per 100 000 population ranged from 20.53 (20.13 <or= 95% confidence interval <or= 20.94) in 2002 to 37.96 (37.42 <or= 95% confidence interval <or= 38.51) in 2006. The average estimated number of annual prevalent cases was 14 103, indicating 28.91 per 100 000 average prevalence over a 5-year period. Males predominated. We found that 32.4% had history of alcohol abuse, and 14.6% was related to steroid. Bilateral involvement was noticed in 37%. Besides arthroplasty, decompression was the most frequently performed joint-preserving procedure. We believe that the results serve as important baseline for understanding the disease.

Characterization of mouse clonal mesenchymal stem cell lines established by subfractionation culturing method

AIM To characterize single-cell-derived mouse clonal mesenchymal stem cells (mcMSCs) established with bone marrow samples from three different mouse strains. METHODS We established mcMSC lines using subfractionation culturing method from bone marrow samples obtained from long bones. These lines were characterized by measuring cell growth, cell surface epitopes, differentiation potential, lineage-specific gene expression and T-cell suppression capability. Nonclonal MSCs isolated by the conventional gradient centrifugation method were used as controls. RESULTS All mcMSC lines showed typical nonclonal MSC-like spindle shape morphology. Lines differed in optimal growth density requirement. Cell surface epitope profiles of these mcMSC lines were similar to those of nonclonal MSCs. However, some lines exhibited different expression levels in a few epitopes, such as CD44 and CD105. Differentiation assays showed that 90% of the mcMSC lines were capable of differentiating into adipogenic and/or chondrogenic lineages, but only 20% showed osteogenic lineage differentiation. T-cell suppression analysis showed that 75% of the lines exhibited T-cell suppression capability. CONCLUSION mcMSC lines have similar cell morphology and cell growth rate but exhibit variations in their cell surface epitopes, differentiation potential, lineage-specific gene expression and T-cell suppression capability.

Revision Total Hip Arthroplasty Using an Extensively Porous Coated Femoral Stem

Background To determine the benefit of an extensively porous coated femoral stem in patients receiving revision total hip arthroplasty. Methods This study reviewed the results of 35 patients who received a revision total hip arthroplasty with extensively porous coated femoral stem between August, 1996, and December, 2002. The mean follow-up period was 77.5 months. The clinical and radiological results were evaluated by the Harris hip score and serial roentgenographic findings. Results The preoperative and postoperative Harris hip score was 68.3 and 92.5, respectively. Radiographically, none of the acetabular components showed any evidence of migration, tilt, rotation, or shedding of metal particles. In addition, none of the femoral components showed evidence of subsidence, pedestal, or shedding of metal particles. Twenty-two hips had a mild stress shield and 2 hips had a moderate stress shield. The perioperative complications encountered were deep vein thrombosis (1 case), mild heterotopic ossification (4 cases), intraoperative periprosthetic fractures (1 case), and nonunion of the trochanteric osteotomy site (2 cases). Conclusions Extensively porous coated femoral stems and acetabular components produce excellent clinical and radiological results in revision total hip arthroplasty.

Outcome of total hip arthroplasty for avascular necrosis of the femoral head in systemic lupus erythematosus.

This study evaluated the result of total hip arthroplasty (THA) for avascular necrosis of the femur head (AVNFH) in systemic lupus erythematosus (SLE) patients. Nineteen THAs were performed on 13 patients with SLE. The results of these patients were compared with the results of the control group (19 patients) who had THR due to AVNFH with none-SLE conditions. The Harris hip score increased from a preoperative average of 65.3 points to 94.9 at the most recent follow-up. In the control group, the mean HHS was 67.2 preoperatively and 96.1 postoperatively at the last follow-up. No significant difference was found between SLE patients and non-SLE patients who underwent hip arthroplasty. In conclusion, THA is an acceptable treatment for achieving functional improvement in patients who had SLE and AVNFH.

Clinical results of auto-iliac cancellous bone grafts combined with implantation of autologous bone marrow cells for osteonecrosis of the femoral head: a minimum 5-year follow-up.

Purpose There are no reports about bone graft and cell therapy for the osteonecrosis of femoral head (ONFH). We prospectively evaluated the clinical results of auto-iliac cancellous bone grafts combined with implantation of autologous bone marrow cells for ONFH. Materials and Methods Sixty-one hips in 52 patients with ONFH treated with bone graft and cell therapy were enrolled, and the average follow-up of the patients was 68 (60-88) months. Necrotic lesions were classified according to their size by the Steinberg method and location of necrosis. Results At the last follow-up, the percentage of excellent or good results was 80% (12/15 hips) in the small lesion group, 65% (17/26 hips) in the medium size group, and 28% (6/20 hips) in the large size group. The procedures were a clinical success in 4 of 5 hips (80%) of stage I, 23 of 35 hips (65.7%) of stage II, 7 of 18 hips (38.9%) of stage III, and 1 of 3 hips (33.3%) of stage IV grade, according to the Association Research Circulation Osseous grading system. Among the 20 cases with large sized necrotic lesions, 17 cases were laterally located and this group showed the worst outcomes, with 13 hips (76.5%) having bad or failed clinical results. Conclusion The results of the present study suggested that patients who have a large sized lesion or medium sized laterally located lesion would not be good candidates for the head preserving procedure. However, for medium sized lesions, this procedure generated clinical results comparable to those of other head preserving procedures.

Correlation between stress shielding and clinical outcomes after total hip arthroplasty with extensively porous coated stems.

Relations between stress shielding and the clinical outcomes of total hip arthroplasty(THA) remain topics of debate. This study was performed on 51 patients that underwent unilateral primary THA with an extensively porous coated stem. Contralateral normal femurs were used as controls. Dual energy x-ray absorptiometry data was used to quantify bone mineral density(BMD) on proximal femurs. Clinical outcomes were estimated by using Harris hip scores (HHSs). BMD in operated sides were lower than in control sides. HHS and pain scores were not related to BMD changes. An extensively porous coated stem can be used for THA and that concerns regarding the effects of stress shielding of the proximal femur are unwarranted.

Total hip arthroplasty using S-ROM prosthesis for dysplastic hip.

Purpose The purpose of this study was to evaluate the clinical and radiological results of total hip arthroplasty using a proximal modular femoral stem in patients who had secondary coxarthrosis associated with a dysplastic hip. Materials and Methods Forty-two patients (45 hips) with secondary coxarthrosis were evaluated after undergoing primary total hip arthroplasty using an S-ROM proximal modular femoral stem. The average follow-up was 80 months (range: 60 to 96 months). Clinical and radiological assessments were performed based on the Harris hip score and the radiological changes around the prosthesis. Results The average Harris hip score improved from 52.2 points to 88.5 points. All femoral stems showed stable fixation; there were 37 cases by bony ingrowth and 8 cases by stable fibrous ingrowth. Neither osteolysis nor progressive radiolucent lines around the femoral stem were found at the last follow-up. Forty-one hips (91.9%) revealed excellent or good clinical results at the most recent follow-up. Conclusion For advanced secondary coxarthrosis, total hip arthroplasty with the use of the proximal modular femoral stem yielded good mid-term results with respect to the clinical and radiological criteria.

Cementless Revision Total Hip Arthroplasty with Ceramic Articulation

Purpose The results of ceramic-on-ceramic (CoC) bearing surfaces in primary total hip arthroplasty (THA) were well known. However, it was not known in revision THA. The purpose of this study is to report the results of revision THA with ceramic articulation. Materials and Methods A total of 112 revision THAs were evaluated. The mean age at the time of surgery was 51.6 years (27.7 to 84.2 years). The mean duration of the follow-up periods was 6.3 years (2.3 to 11.4 years). Results The Harris hip scores improved from an average of 56.2 at the index surgery to an average of 93.3 at the last follow-up (P<0.001). None of hips showed osteolysis or ceramic head fracture. One hip showed aseptic loosening in the acetabular component with squeaking that caused a re-revision. There were nine cases of dislocation. The survivorship at 5 years was 94.5% (95% confidence interval, 87.9% to 97.6%) with revision for any reason as the endpoint and 100% with femoral revision. Conclusion The ceramic articulation is one of good bearing options for revision THA in patients with a long life expectancy.