• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.451-456
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• 2008

Total knee arthroplasty(TKA) using computer-assisted navigation has been increased in order to improve the accuracy of femoral and tibial components implantation. Recently, a few clinical studies have reported on the femoral stress fracture after TKA using computer-assisted navigation. The purpose of this study is to investigate the stress concentration around the femoral pin-hole for different pin-hole diameter, the modes of pin penetration by finite element analysis to understand the effects of pin-hole parameters on femoral stress fracture risk. A three-dimensional finite element model of a male femur was reconstructed from 1 mm thick computed tomography(CT) images. The bone was rigidly fixed to a 25 mm above the distal end and 1500 N of axial compressive force and 12 Nm of axial torsion were applied at the femoral head. For all cases, transcortical pin penetration mode showed the highest stress fracture risk and unicortical pin penetration mode showed the lowest stress concentration. Pin-hole diameter increased the stress concentration, but pin number did not increase the stress dramatically. The results of this study provided a biomechanical guideline for pin-hole fracture risk of the computer navigated TKA.

• Journal of the Korean Orthopaedic Association
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• v.52 no.1
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• pp.92-96
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• 2017

Postoperative infection from total knee arthroplasty (TKA) is an issue drawing great attention, which can manifest as a local or general infection. Its development into sepsis has also occasionally been reported. Such sepsis is a critical complication that can spread to various parts of the body, which can ultimately lead to mortality. However, the cases where infection has spread to the spine do not have clear clinical signs, making diagnosis difficult. These cases are not found in the literature. Therefore, this is a case study on both postoperative infection from TKA that has developed into sepsis and spread to the spine.

• 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.

• Knee surgery & related research
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• v.30 no.4
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• pp.326-333
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• 2018

Purpose: To evaluate the reliability and validity of the femorotibial mechanical axis angle from radiographs in the weight bearing (WB) and supine positions compared with navigation-measured values. Materials and Methods: Sixty-eight cases of navigation-assisted total knee arthroplasty (TKA) were included. The pre- and postoperative whole leg radiographs (WLRs) in WB and supine positions were compared with the initial and final navigation values. Results: The mean mechanical axis angle from the preoperative WBWLR and navigation were not statistically different (p=0.079) and were correlated strongly with each other (intraclass correlation [ICC], 0.818). However, on postoperative measurements, although the WBWLR and navigation values were not different (p=0.098), they were not correlated with each other (ICC, 0.093). The standard error of measurement was $1.8^{\circ}{\pm}3.6^{\circ}$ for the preoperative WBWLR and $2.5^{\circ}{\pm}4.8^{\circ}$ for the postoperative WBWLR. The validity that was determined by the Bland-Altman plot was not acceptable for both pre- and postoperative measurements. Conclusions: The preoperative WBWLR could provide accurate but not precise measurement value of the femorotibial mechanical axis angle for navigation-assisted TKA, and postoperative measurements in navigation were not comparable with radiographic measurements. The lack of agreement was found between the radiographic and navigation measurements of the coronal alignment regardless of pre- or postoperative evaluation although the accuracy was found acceptable. Level of Evidence : Level 4.

• 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.

• The Korean Journal of Pain
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• v.22 no.3
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• pp.234-240
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• 2009

Background: The purpose of this study was to compare the analgesic effect of 0.25% and 0.5% levobupivacaine for real time ultrasound guided single-injection femoral nerve block for the patients who are undergoing bilateral total knee arthroplasty (TKA). Methods: Femoral nerve block was done to all patients with 20 ml of 0.9% normal saline on one leg and 20 ml of 0.25% levobupivacaine on the other leg for group I (n = 16) and 0.5% levobupivacaine for group II (n = 15) with 1:200,000 epinephrine and using real-time ultrasound and a nerve stimulator. The data concerning the verbal numerical rating scale (VNRS) for each leg, the consumption of the intravenous patient-controlled analgesia (IV PCA) and the demands for the additional analgesics was collected at 0, 1, 6, 12, 24 and 48 hours after the operation. Results: The legs on which femoral nerve block was done with levobupivacaine showed a lower VNRS score than the legs with normal saline in either group I or group II. The VNRS scores between the two legs, the consumption of the IV PCA and the demand for additional analgesics showed no significant differences between the groups. Conclusions: Our results demonstrate that single-injection femoral nerve block using real-time ultrasound with either 0.25% levobupivacaine or 0.5% levobupivacaine 20 ml provides a good effect for the postoperative pain control after TKA.

• Journal of the Korean Orthopaedic Association
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• v.54 no.5
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• pp.411-417
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• 2019

Purpose: To compare the clinical outcomes of single injection adductor canal block (SACB), continuous adductor canal block (CACB), and the concomitant use of transdermal buprenorphine after total knee arthroplasty (TKA). Materials and Methods: A total of 125 patients who underwent TKA were divided into three groups and the clinical results were retrospecitively compared. Group I was comprised of patients with pain controlled by SACB (n=41). Group II consisted of patients with pain controlled by both SACB and transdermal buprenorphine (10 ㎍/h) (n=44). Group III contained patients with pain controlled by CACB (n=40). The visual analogue scale (VAS) was used as the pain control indicator and the patients were measured on a VAS for resting on the bed (VAS-Rest) at 12 hours, 24 hours, and 48 hours after surgery. The VAS while doing continuous passive motion (VAS-CPM) on the first and second postoperative day was also measured. In addition, the total amount of medications used (Butopahn, Tridol, and Ketorac) for the intravenous patient controlled analgesia (PCA) was counted for 48 hours after surgery. As the indicator of the functional recovery outcome, the incidence of nausea and vomiting was observed for 48 hours after surgery. The maximum knee joint flexion range and maximum walking distance on the first and second postoperative day, and the total length of stay at the hospital were compared. Results: The VAS-Rest was similar in the three groups at 12 hours after surgery, but at 24 hours and 48 hours after surgery, group II and III a lower VAS-CPM and total amount of medications used for PCA than group I (p<0.05). The three groups showed a low incidence of nausea and vomiting, maximum knee joint flexion range, and similar walking distance and total length of stay at the hospital. Conclusion: The combination of SACB and transdermal buprenorphine has great pain control effect initially. On the other hand, it is not associated with catheter complications and it is convenient to use and safety toward the renal function. Therefore, the concomitant use of SACB and transdermal buprenorphine can be an effective pain control method after TKA.

• The Korean Journal of Pain
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• v.32 no.1
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• pp.30-38
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• 2019

Background: The adductor canal block (ACB) is an effective intervention for postoperative analgesia following total knee arthroplasty (TKA). However, the ideal ACB regimen has not yet been established. We compared the analgesic effects between a continuous ACB group and fentanyl-based intravenous patient-controlled analgesia (IV-PCA) with a single-shot ACB group. Methods: Patients who underwent TKA were randomly allocated to either a continuous ACB group (Group CACB) or IV-PCA with a single-shot ACB group (Group IVACB). Before the surgery, ultrasound guided ACB with 0.5% ropivacaine 20 cc was provided to all patients. Before skin incision, the infusion system (0.2% ropivacaine through an adductor canal catheter in group CACB vs. intravenous fentanyl in group IVACB) was connected. The postoperative pain severity; the side effects of local anesthetics and opioids; administration of rescue analgesics and anti-emetics; and sensorimotor deficits were measured. Results: Postoperative pain severity was significantly higher in the IVACB group at 30 min, 4 h, 24 h, and 48 h after surgery. The averages and standard deviations (SD) of the NRS score of postoperative pain were $0.14{\pm}0.37$, $4.57{\pm}2.37$, $6.00{\pm}1.63$, and $4.28{\pm}1.49$, respectively in the IVACB group. Rescue analgesic requirements and quadriceps muscle strength were not statistically different between the groups throughout the postoperative period. Moreover, rescue antiemetic requirements were higher in group IVACB than group CACB. Conclusions: In this study, the continuous ACB provided superior analgesia and fewer side effects without any significant motor deficit than the IV-PCA with a single-shot ACB.

• Journal of the Korean Orthopaedic Association
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• v.55 no.6
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• pp.545-549
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• 2020

Although rare, the treatment options for a medial collateral avulsion fracture during total knee arthroplasty (TKA) range from conservative management using a cast and orthosis to internal fixation using metal screws. Bioabsorbable suture anchors have been used to replace metal fixators with distinct advantages, such as biocompatibility, radiolucency, and unnecessary second removal surgery, but complications, such as osteolysis, have been reported. This paper reports a potential risk of an extensive osteolysis-related suture anchor fixation of a medial collateral ligament (MCL) avulsion fracture during TKA in conjunction with a literature review.

• Journal of the Korean Orthopaedic Association
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• v.56 no.3
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• pp.253-260
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• 2021

Purpose: The least constrained prosthesis is generally recommended in primary total knee arthroplasty (TKA). Nevertheless, a varus/valgus constrained (VVC) prosthesis should be implanted when a semi-constrained prosthesis is not good for adequate stability, especially in the coronal plane. In domestic situations, however, the VVC prosthesis could not always be prepared for every primary TKA case. Therefore, it is sometimes impractical to use a VVC prosthesis for unsual unstable situations. This study provides information for preparing VVC prostheses in the preoperative planning of primary TKA through an analysis of primary VVC TKA cases. Materials and Methods: This study reviewed 1,797 primary TKAs, performed between May 2003 and February 2016. The reasons for requiring VVC prosthesis and the preoperative conditions in 29 TKAs that underwent primary TKA with a VVC prosthesis were analyzed retrospectively. Results: In primary TKA, 29 cases (1.6%) in 27 patients (6 male and 21 female) used VVC prosthesis. Two patients underwent a VVC prosthesis on both knees. The mean age of the patients was 63.4 years old (34-79 years). The mean flexion contracture was 16.2° (-20°-90°), and the mean angle of great flexion was 111.7° (35°-145°). The situations requiring a VVC prosthesis were severe valgus deformity in 10 knees, knee stiffness requiring extensive soft tissue release in 10 knees, previously injured collateral ligaments in five knees, and distal femoral bone defect due to avascular necrosis in four knees. The mean tibiofemoral angle was 25.7° (21°-43°) in 10 cases with a valgus deformity. The mean flexion contracture was 37.5° (20°-90°), and the mean range of motion was 48.5° (10°-70°) in 10 cases with knee stiffness. Conclusion: The preparation of VVC prosthesis is recommended, even for primary TKA in cases of severe valgus deformity (tibiofemoral angle>20°), stiff knee (the range of motion: less than 70° with more than 20° flexion contracture), and the cases with a previous collateral ligament injury. This information will help in the preparation of adequate TKA prostheses for unusual unstable situations.