• Journal of Biomedical Engineering Research
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• v.34 no.1
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• pp.14-23
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• 2013

In this study, biomechanical stability of the newly developed revision total knee arthroplasty (rTKA) was evaluated through strain and stress distribution analysis within the implanted proximal tibia using a three-dimensional finite element (FE) analysis. 2000N of compressive load (about 3 times body weight) was applied to the condyle surface on spacer, sharing by the medial (60%) and lateral (40%) condyles simulating a stance phase before toe-off. The results showed that PVMS within the revision total knee arthroplasty and the proximal tibia were less than yield strength considering safe factor 4.0 (rTKA: less than 10%, Cortical bone: less than 70%, Cancellous bone: less than 70%). The materials composed of them and the strain and stress distributions within the proximal tibia were generally well matched with those of a traditional revision total knee arthoplasty (Scorpio TS revision system, Stryker Corp., Michigan, USA) without the critical damage strain and stress, which may reduce the capacity for bone remodeling, leading to bone degeneration. This study may be useful to design parameter improvement of the revision total knee arthoplasty in biomechanical stability point of view beyond structural stability of revision total knee arthoplasty itself.

• Journal of Medicine and Life Science
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• v.20 no.1
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• pp.32-37
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• 2023

The demand for total knee arthroplasty (TKA) is rapidly increasing worldwide. The most common indication for TKA is osteoarthritis (OA); however, some patients with rheumatoid arthritis (RA) also undergo TKA. This study aimed to investigate the effects of RA on TKA. Our findings revealed that patients with RA underwent TKA at a younger age than did patients with OA. However, contrary to the findings of pre-21st century studies, the average age of TKA among patients with RA was not significantly different from that of patients with OA. Additionally, patients with RA had a 1.5-fold higher risk of undergoing TKA. Although not statistically significant, patients with RA had a higher revision TKA rate, a shorter time until revision TKA, and underwent more revision TKAs due to infections than did patients with OA. An analysis of factors that affect revision TKA revealed that the risk of revision increased if the erythrocyte sedimentation rate and C-reactive protein levels were increased at the time of TKA. This study showed that patients with RA have a slightly higher risk of undergoing TKA than did patients with OA. Furthermore, the presence of inflammation at the time of TKA increases the risk of revision; therefore, inflammation should be adequately controlled before performing TKA.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.1213-1214
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• 2012

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.398-406
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• 2018

Background: Hypoalbuminemia (serum albumin < 3.5 g/dL) is associated with increased morbidity and mortality in patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA). However, costs associated with hypoalbuminemia remain unknown. This study investigated the effect of serum albumin on direct treatment costs, length of stay (LOS), and readmissions for primary and revision THA and TKA patients. Methods: All adult patients at a single institution undergoing primary or revision THA or TKA between January 2014 and December 2016 were retrospectively reviewed. Patients were stratified by preoperative serum albumin level. The primary outcome was total direct costs at index hospitalization. Secondary outcomes included LOS and readmission within 30 days. Multivariable regressions were utilized to adjust for demographics and comorbidities. Results: Of 3,785 patients, 114 (3.0%) had hypoalbuminemia. After adjustment, hypoalbuminemia was associated with a 16.2% increase in costs (${\beta}=0.162$; 95% confidence interval [CI], 0.112 to 0.213; p < 0.001), representing an average cost increase of $3,383 (95% CI, $2,281 to $4,485) relative to costs for serum albumin > 4.5 g/dL. The increased total costs were significantly higher in revision ($4,322, p = 0.034) than in primary ($3,446, p < 0.001) procedures. In adjusted regression, each 1.0 g/dL increase in serum albumin yielded a 6.6% reduction in costs (${\beta}=-0.066$; 95% CI, -0.090 to -0.042]; p < 0.001), for average savings of $1,282 (95% CI, $759 to $1,806) per unit albumin. Adjusted regressions demonstrated that a 1-point increase in serum albumin reduced readmissions by 53% (odds ratio, 0.47; 95% CI, 0.31-0.73; p = 0.001) and LOS by 0.6 days (${\beta}=-0.60$; 95% CI, -0.76 to -0.44; p < 0.001). Conclusions: Hypoalbuminemia is associated with increased total direct costs, LOS, and readmissions following primary and revision THA and TKA. Future efforts to predict and address total costs should take into consideration the patient's preoperative serum albumin levels.

• Archives of Reconstructive Microsurgery
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• v.15 no.2
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• pp.111-116
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• 2006

An infection after total knee arthroplasty has many complications such as severe bone defect, skin and soft tissue problems, devastated general condition, so arthrodesis is preferred as treatment option. However, poor bony contact due to severe bone defect and inadequate conditions of the soft tissue often cause nonunion or severe limb shortening after arthrodesis. More over these conditions, it is not easy to choose appropriate fixative devices. In these situations, the arthrodesis using vascularized fibular graft can be the solution. Vascularized fibular graft (VFG) can playa role as a suitable material for the treatment of bone defects. And VFG can overcome poor blood circulation caused by scar tissues, and can be relatively more durable and adequate length. In the long term, VFG can be hypertrophied by weight bearing, and will give mechanical stablility. The purpose of the paper is to report the successful results of arthrodesis using VFG in a patient who got extensive bone defect after failed revision total knee arthroplasty with infection.

• Archives of Plastic Surgery
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• v.45 no.3
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• pp.280-283
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• 2018

Knee revision arthroplasty following peri-prosthetic joint infections is a formidable challenge. Patients are at a high risk of recurrent infection, and the soft tissue over the revised implant is often of questionable quality. Flap reconstruction has improved the salvage rates of infected arthroplasties, and should be considered in all cases of revision arthroplasty. We present a challenging case requiring staged reconstruction with two free latissimus dorsi flaps after the initial use of a medial gastrocnemius flap.

• Journal of the Korean Orthopaedic Association
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• v.56 no.1
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• pp.87-92
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• 2021

The radiographic findings of an osteolytic lesion in the knee may indicate numerous possible impressions. Furthermore, osteolysis is a possible cause if there is a surgical history of total knee arthroplasty (TKA). The authors diagnosed osteolysis of the fibular head after aseptic loosening of the tibial component of a cemented TKA in an 83-year-old female patient who visited with right knee pain and report their treatment with revision TKA along with a literature review.

• Journal of the Korean Arthroscopy Society
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• v.13 no.1
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• pp.39-45
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• 2009

Purpose: To investigate the outcome of arthroscopic treatment for the complications of knee arthroplasty and to evaluate the effectiveness of arthroscopy. Materials and Methods: We analyzed 25 patients who underwent arthroscopy to treat complications of knee arthroplasty between May 1992 and June 2008. Nineteen cases out of 25 had total knee arthroplasty (TKA) and the remaining 6 cases had unicompartmental knee arthroplasty (UKA). Before arthroscopy, physical examinations and radiographic evaluations were carried out to find out the causes of complications. Joint fluid aspiration and hematologic evaluation were added when infection was suspected. Results: Among the diagnosis at the time of arthroscopy, there were 11 cases of infection, 6 cases of stiffness due to adhesion and fibrosis, and 2 cases of soft tissue impingement in the cases of TKA. Among the cases of UKA, one for each case of meniscal tear, subluxation of mobile insert, hemarthrosis, cement loose body, soft tissue impingement, and stiff knee was found. Nine out of 11 patients who had infection were treated successfully with arthroscopy but the remaining 2 cases underwent revision arthroplasty. Seven patients with arthrofibrosis had improved range of motion from $65^{\circ}$ preoperatively to $105^{\circ}$ postoperatively. The others also showed successful results after arthroscopy. Conclusion: Arthroscopy to treat complications after knee arthroplasty was a safe and effective method when appropriate selection of patients was made.

• Clinics in Orthopedic Surgery
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• v.10 no.4
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• pp.427-432
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• 2018

Background: The purpose of this study was to evaluate the usefulness of sonication technique for microbiological diagnosis and the sterility of the recycled autoclaved femoral components from infected total knee arthroplasty (TKA) using a sonication method. Methods: Nineteen femoral implants explanted from patients with infected TKA were sterilized with a standard autoclave method. Standard culture of the fluid before and after sonication of the sterilized implants was performed to detect pathogenic microorganisms. Additional experiments were performed to evaluate the sterility of the recycled implant by inducing artificial biofilm formation. Methicillin-resistant Staphylococcus aureus (MRSA) was inoculated into 10 implants and sterilization in a standard autoclave was performed, and then the fluid was cultured before and after sonication. Results: Two of the 19 sterilized implants were positive for growth of bacteria after sonication, whereas no growth was detected in the cultured fluid from the sterilized implants before sonication. The bacteria were Staphylococcus species in all two cases. In one of 10 implants inoculated with MRSA, the culture was positive for growth of bacteria both before and after sonication. However, Staphylococcus epidermidis was cultured from both occasions and thus this implant was thought to be contaminated. Conclusions: We found sonication for identification of pathogens could be helpful, but this finding should be interpreted carefully because of the possibility of contamination. Sterilization of an infected femoral implant with an autoclave method could be a good method for using the temporary articulating antibiotic spacer in two-stage revision arthroplasty.

• Journal of the Korean Orthopaedic Association
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• v.54 no.1
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• pp.52-58
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• 2019

Purpose: Fungal periprosthetic joint infection (PJI) is a rare but devastating complication following total knee arthroplasty (TKA). On the other hand, a standardized procedure regarding an accurate treatment of this serious complication of knee arthroplasty is lacking. The clinical progress of staged reimplantation in patients who had fungus-related PJI after TKA was reviewed retrospectively. Materials and Methods: Ten patients who had a fungal related PJI after TKA between 2006 and 2017 using staged reimplantation surgery were reviewed. These patients were compared with 119 patients who had a PJI in the same period. The failure rate of infection control, intravenous antimicrobial using the period, and the clinical results were evaluated by comparing the range of motion and Korean knee score (KKS) between pre-staged reimplantation and the last follow-up. Results: In the fungal infection group, 7 out of 10 cases (70.0%) had failed in infection control using staged reimplantation and in the non-fungal group, 7 out of 119 cases (5.9%) had failed (p=0.04). In the non-fungal group, the mean duration of antibiotics was 6.2 weeks. In the fungus group, the mean duration of antibiotics was 15.3 weeks, which was 9.1 weeks longer (p<0.001). The range of motion of the knee was increased in the two groups (p=0.265). At the last follow-up, the KKS was 71.01 points in the non-fungal group and 61.3 points in the fungal group (p=0.012). Erythrocyte sedimentation rate and C-reactive protein (CRP) decreased in the two groups, but the CRP was significantly different in the two groups (p=0.007). Conclusion: The treatment of fungus-related PJIs using staged reimplantation showed uneven clinical progress and unsatisfactory clinical improvements compared to non-fungal PJI. Therefore, it is necessary to consider the use of an antifungal mixed cement spacer at resection arthroplasty and oral antifungal agent after reimplantation.