Young Yul Kim

Semitendinosus Tendon Augmentation for a Large Defect after Achilles Tendon Rupture: Two Case Reports:

Acute Achilles tendon ruptures usually occur in people between the ages of 30 and 40 years who participate in sports-related activities. Operative repair has become the standard treatment for acute Achilles tendon rupture in this group of patients. In chronic cases or if the gap is larger than 5 cm in revision surgery, end-to-end repair of the torn Achilles tendon is difficult and V-Y advancement will likely be insufficient. Often surgeons perform transfer of the flexor hallucis longus (FHL) tendon or use an Achilles tendon allograft, but it is difficult to harvest the FHL tendon in the deep midfoot area, and there are disadvantages to using commercial allograft. For this injury, we perform a V-Y advancement and a semitendinosus tendon transfer. Using a semitendinosus tendon in the repair of the Achilles rupture has to our knowledge not been reported. We report two patients in whom this operative technique was used. The procedure was simple and we had excellent results.

Posteromedial compartment cement extrusion after unicompartmental knee arthroplasty treated by arthroscopy: a case report

Unicompartmental knee arthroplasty (UKA) with extrusion of cement into the posterior compartment of the knee is uncommon. Various problems after a UKA procedure, such as aseptic loosening, polyethylene wear and progressive arthritis have been reported. This study will report on a patient with extrusion of cement fragments into the posteromedial compartment of the knee after a UKA procedure. This complication was treated successfully with the direct posterior–posterior triangulation arthroscopic visualization method. In cementing the prosthesis, it is of paramount importance to take caution to completely remove extruded cement remnants in order to prevent this complication during UKA.

Fabrication of dual-pore scaffolds using SLUP (salt leaching using powder) and WNM (wire-network molding) techniques.

In this study, a novel technique was proposed to fabricate dual-pore scaffolds combining both SLUP (salt leaching using powder) and WNM (wire-network molding) techniques. This technique has several advantages: solvent-free, no limit on the use of thermoplastic polymers as a raw material, and easiness of fabricating scaffolds with dual-scale pores that are interconnected randomized small pores. To fabricate dual-pore scaffolds, PCL and NaCl powders were mixed at a certain ratio. Subsequently, needles were inserted into a designed mold, and the mixture was filled into the mold thereafter. Subsequently, after the mold was pressurized, the mold was heated to melt the PCL powders. The PCL/NaCl structure and needles were separated from the mold. The structure was sonicated to leach-out the NaCl particles and was dried. Consequently, the remaining PCL structure became the dual-pore scaffold. To compare the characteristics of dual-pore scaffolds, control scaffolds, which are 3D plotter and SLUP scaffolds were fabricated.

Load-bearing capacity and biological allowable limit of biodegradable metal based on degradation rate in vivo.

In this study, a newly developed Mg-Ca-Zn alloy for low degradation rate and surface erosion properties was evaluated. The compressive, tensile, and fatigue strength were measured before implantation. The degradation behavior was evaluated by analyzing the microstructure and local hardness of the explanted specimen. Mean and maximum degradation rates were measured using micro CT equipment from 4-, 8-, and 16- week explants, and the alloy was shown to display surface erosion properties. Based on these characteristics, the average and minimum load bearing capacities in tension, compression, and bending modes were calculated. According to the degradation rate and references of recommended dietary intakes (RDI), the Mg-Ca-Zn alloy appears to be safe for human use.

The fabrication of well-interconnected polycaprolactone/hydroxyapatite composite scaffolds, enhancing the exposure of hydroxyapatite using the wire-network molding technique.

In this study, the fabrication method was proposed for the well-interconnected polycaprolactone/hydroxyapatite composite scaffold with exposed hydroxyapatite using modified WNM technique. To characterize well-interconnected scaffolds in terms of hydroxyapatite exposure, several assessments were performed as follows: morphology, mechanical property, wettability, calcium ion release, and cell response assessments. The results of these assessments were compared with those of control scaffolds which were fabricated by precision extruding deposition (PED) apparatus. The control PED scaffolds have interconnected pores with nonexposed hydroxyapatite. Consequently, cell attachment of proposed WNM scaffold was improved by increased hydrophilicity and surface roughness of scaffold surface resulting from the exposure of hydroxyapatite particles and fabrication process using powders. Moreover, cell proliferation and differentiation of WNM scaffold were increased, because the exposure of hydroxyapatite particles may enhance cell adhesion and calcium ion release.

Extra-Articular Ganglion Cysts around the Knee Joint

Purpose The purpose of this study was to report clinical results of open excision of extra-articular ganglion cysts around the knee joint combined with arthroscopic management of intra-articular pathologies if present. Materials and Methods Of the total 107 cases of cystic lesions around the knee, 23 cases of extra-articular ganglion cysts were reviewed between January 2006 and July 2011. There were 13 males and 10 females with a mean age of 48 years (range, 30 to 73 years). The mean follow-up duration was 40 months (range, 30 to 60 months). Preoperative magnetic resonance imaging (MRI) scan was done in all cases. Open surgical excision of the cyst was performed after arthroscopic management of intra-articular pathologies in all but 1 case. At the last follow-up, Lysholm and International Knee Documentation Committee (IKDC) scores were evaluated and MRI was conducted to detect recurrence. Results The mean Lysholm and IKDC scores showed significant improvement (p=0.005 and 0.013, respectively).The location of the cysts was anterior in 9, lateral in 7, medial in 6, and posterosuperior in 1. Intra-articular pathologies were found in 16/23 cases (69.6%). In 10/23 cases (43%), the cyst was connected to the knee joint. Three months postoperative MRI did not show any recurrence of ganglion cysts except for 1 case. Conclusions In the treatment of extra-articular ganglion cysts, MRI can be useful for detecting intra-articular lesions and connecting orifices, and arthroscopic management of intra-articular pathologies with open excision of the cyst should be considered as a viable treatment option.

Fabrication of Dual-pore Scaffolds Using a Combination of Wire-Networked Molding (WNM) and Non-solvent Induced Phase Separation (NIPS) Techniques

In this study, to fabricate dual-pore scaffolds with interconnected pores, Non-solvent Induced Phase Separation (NIPS) and Wire-Network Molding (WNM) techniques were combined. First, a mold with uniform slits was prepared, and needles were inserted into the mold. Subsequently, polycaprolactone (PCL) pellets were dissolved in tetrahydrofuran (THF) at a specified ratio. The slurry was mixed using hot plate stirrer at 1200 rpm for 24 hours at 40 °C. The PCL slurry was subsequently injected into the mold. Thereafter, to exchange the THF (solvent) with the ethanol (non-solvent), the mold was soaked in an ethanol bath. After removing the mold from the ethanol bath, the needles were removed from the mold. Consequently, dual-pore scaffold with interconnected pores was obtained. The surface morphology of the fabricated scaffolds were observed using Scanning Electron Microscope (SEM). Moreover, cell culture experiments were performed using the CCK-8 assay, and the characteristics of cells grown on the dual-pore scaffolds were assessed and were compared with the NIPS-based 3D plotting scaffold.

Locked floating first metatarsal: open reduction and no fixation - case report.

Level of Evidence: V, Expert Opinion

Clinical Usefulness of Long-term Application of Fentanyl Matrix in Chronic Non-Cancer Pain: Improvement of Pain and Physical and Emotional Functions

Background Opioids are recently recommended for those who do not gain adequate pain relief from the use of acetaminophen or nonsteroidal anti-inflammatory drugs. Medical opioids are administered in various routes, and transdermal opioid products that can make up for the weaknesses of the oral or intravenous products have been developed. This study is to evaluate the clinical usefulness of fentanyl matrix in terms of the long-term improvement in pain and physical and mental functions. Methods This was a multicenter, open, prospective, observational study that was conducted in 54 institutions in Korea. Patients with non-cancerous chronic pain completed questionnaires, and investigators also completed questionnaires. A total of 1,355 subjects participated in this study, and 639 subjects completed the study. Subjects received transdermal fentanyl matrix (12 µg/hr, 25 µg/hr, or 50 µg/hr depending on the patients response and demand). Subjects visited at 29 ± 7 days, 85 ± 14 days, and 169 ± 14 days after administration, respectively, to receive drug titration and fill out the questionnaires. The results were analyzed using the intention-to-treat (ITT) analysis, full analysis set (FAS), and per-protocol (PP) analysis. The FAS analysis included only 451 participants; the PP analysis, 160 participants; and the ITT analysis, 1,355 participants. Results The intensity of pain measured by the Numeric Rating Scale decreased from 7.07 ± 1.78 to 4.93 ± 2.42. The physical assessment score and mental assessment score of the Short-Form Health Survey 12 improved from 28.94 ± 7.23 to 35.90 ± 10.25 and from 35.80 ± 11.76 to 42.52 ± 10.58, respectively. These differences were significant, and all the other indicators also showed improvement. Adverse events with an incidence of ≥ 1% were nausea, dizziness, vomiting, and pruritus. Conclusions The long-term administration of fentanyl matrix in patients with non-cancerous pain can reduce the intensity of pain and significantly improves activities of daily living and physical and mental capabilities.

Assessments for bone regeneration using the polycaprolactone SLUP (salt‐leaching using powder) scaffold

Salt-leaching using powder (SLUP) scaffolds are novel salt-leaching scaffolds with well-interconnected pores that do not require an organic solvent or high pressure. In this study, in vitro and in vivo cell behaviors were assessed using a PCL (polycaprolactone) SLUP scaffold. Moreover, using PCL, conventional salt-leaching and 3D-plotted scaffolds were fabricated as control scaffolds. Morphology, mechanical property, water absorption, and in vitro/in vivo cell response assessments were performed to clarify the characteristics of the SLUP scaffold compared with control scaffolds. Consequently, we verified that the interconnectivity between the pores of the SLUP scaffold was enhanced compared with conventional salt-leaching scaffolds. Moreover, in vitro cell attachment and proliferation of the SLUP scaffold were higher than those of the 3D-plotted scaffold because of their morphological characteristic. Furthermore, we revealed that new bone formation and bone ingrowth of the SLUP scaffold was superior to those of the calvarial defect model and 3D-plotted scaffold because of the high porosity and improved interconnectivity of pores by the SLUP technique without high pressure using powders.