Sahnghoon Lee

Synovial membrane-derived mesenchymal stem cells supported by platelet-rich plasma can repair osteochondral defects in a rabbit model.

PURPOSE The aim of this study was to determine the in vivo effectiveness of synovial membrane-derived mesenchymal stem cell (SDSC)-encapsulated injectable platelet-rich plasma (PRP) gel in the repair of damaged articular cartilage in the rabbit. METHODS An osteochondral defect was created in the trochlear groove of the rabbit femur, and the defects were divided into 3 treatment groups: untreated control group, PRP group, and PRP-SDSC group. After 4, 12, and 24 weeks, the tissue specimens were assessed by macroscopic examination and histologic evaluation and stained immunohistochemically for type II collagen and proliferating cell nuclear antigen. In addition, total glycosaminoglycan content was determined at 24 weeks. RESULTS Rabbit PRP contained a high concentration of platelets and high concentration of growth factors compared with those in whole blood. Twenty-four weeks after transplantation, there was fibrous tissue in the control group. In both the PRP group and the PRP-SDSC group, the defects were repaired with hyaline cartilage and exhibited significantly higher safranin O staining, type II collagen immunostaining, glycosaminoglycan content, cumulative histologic scores, and number of proliferating cell nuclear antigen-positive cells. However, incomplete bone regeneration and irregular cartilage surface integration were observed in the PRP group. CONCLUSIONS Our results indicate that SDSC-embedded PRP gel could successfully resurface the defect with cartilage and restore the subchondral bone in the rabbit model. CLINICAL RELEVANCE This study indicates that in an animal model, the application of PRP and SDSC in combination for the treatment of local cartilage defects appears promising; however, PRP-SDSC products might be more or less appropriate to treat different types of tissues and pathologies. The clinical efficacy of PRP remains under debate. Therefore further research is needed at both the basic science and clinical levels.

Anterior cruciate ligament reconstruction with use of autologous quadriceps tendon graft.

Anterior cruciate ligament rupture is the most common knee ligament injury. Of the grafts that are used for anterior cruciate ligament reconstruction, bone-patellar tendon-bone is still the most common because of its initial fixation stability and its ultimate tensile strength and elastic modulus, which are superior to those of other graft sources. Hamstring tendon grafts recently have demonstrated functional results equivalent to those of bone-patellar tendon-bone grafts. While most recent studies have failed to demonstrate significant differences between the two types of grafts, many authors have reported on their strengths and weaknesses1-12. While there has been a trend toward better stability in association with bone-patellar tendon-bone grafts, postoperative complications, including anterior knee pain and patellofemoral problems, have been reported frequently13-20. Knee-extension deficits have been reported to occur more frequently in association with bone-patellar tendon-bone grafts as compared with hamstring tendon grafts1,7. Graft laxity and tunnel enlargement have been reported in association with hamstring tendon grafts, and some authors have found persistent muscular deficits in knee flexion and internal rotation strength after treatment with hamstring tendon grafts5,21. In 2004, we reported the early results for a series of patients undergoing anterior cruciate ligament reconstruction with use of a quadriceps tendon autograft22. The central quadriceps tendon-patellar bone autograft has been proposed as a reasonable source of anterior cruciate ligament graft by some authors as it offers adequate mechanical strength and easier rehabilitation, while some postoperative complications can be avoided23-28. The anatomy and mechanical properties of the quadriceps tendon were well described in a series of studies by Staubli et al.27,29-31. The cross-sectional area of the quadriceps tendon was almost twice that of the patellar …

Prognostic significance of peritoneal washing cytology in patients with gastric cancer

Positive peritoneal washing cytology is a poor prognostic factor in patients with gastric cancer. The right therapeutic approach for this condition has not been well documented.

Evaluation of anatomic references for tibial sagittal alignment in total knee arthroplasty.

The authors aimed to demonstrate the relationship between the sagittal mechanical axis of the tibia and other reference axes of the tibia and fibula in patients with advanced osteoarthritis of the knee joints, and then to identify a reliable landmark in order to minimize posterior tibial slope measurement errors. We evaluated 133 osteoarthritic knees with neutral or varus deformity in 64 female and 8 male patients. Axial computed tomographic images of whole tibiae including knee and ankle joints were obtained and reconstructed using 3-dimensional imaging software. Angles between the mechanical axis (MA), the tibial anatomical axis (TAA), the anterior tibial cortex (ATC) and the fibular shaft axis (FSA) were measured, and then medial and lateral tibial slope angles were measured using all axes. Mean angles between MA and the other anatomical reference lines (TAA, ATC and FSA) were 0.9, 2.2 and −2.1°, respectively. The mean values of lateral tibial slopes with respect to MA, TAA, ATC and FSA were 8.7, 10, 12 and 7.3, respectively, and their intra- and inter-observer reliabilities were higher than those of medial tibial slopes. Although posterior tibial slope change markedly according to the reference axis used, the axes used in conventional TKA showed significant correlations with each other, and thus, may be used safely if differences with the mechanical axis are considered. Moreover, the lateral tibial slope might have advantages over the medial tibial slope in terms of restoration of the natural tibial slope.

Simultaneous Bilateral MIS-TKA Results in Faster Functional Recovery

AbstractSimultaneous bilateral TKAs subject patients to more arduous and painful functional recovery and increased risk of hemodynamic complications than staged bilateral TKAs. Minimally invasive TKA (MIS-TKA) reportedly results in more rapid return of function by limiting the amount of soft tissue disruption. We asked whether bilateral MIS-TKA had advantages over conventional TKA with respect to faster functional recovery. We prospectively randomized 30 patients into an MIS group (mini-medial parapatellar approach, 15 patients) and a conventional group (conventional medial parapatellar approach, 15 patients). We recorded range of motion and the time required to regain the ability to walk without assistance. Functional recovery in the MIS group was faster in rehabilitation milestones of walking without assistance and gain in range of motion. Minimally invasive TKA may benefit patients undergoing simultaneous bilateral procedures with faster functional recovery. Level of Evidence: Level II, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Plain Radiograph Fails to Reflect the Alignment and Advantages of Navigation in Total Knee Arthroplasty

The study purposed to determine if a navigation in total knee arthroplasty (TKA) leads to accurate limb alignment and component position than the conventional technique as measured by full length standing radiographs and to evaluate the correlation between navigation and radiographic measurements. A total of 160 knees underwent navigation (n = 80) or conventional (n = 80) TKAs. The frontal femoral alignment was more accurate in navigation TKAs, whereas mechanical axis and frontal tibial alignment were similar in both techniques. Although the intraoperative navigation alignment showed no outliers, postoperative radiographic measure resulted as much as 20% of outliers, and there was no correlation between the two measurements. This lack of correlation and inherent limitations in measuring TKA alignment may bring to question if plain radiograph are useful to determine if alignment achieved by navigation is accurate.

Anatomic single-bundle ACL reconstruction is possible with use of the modified transtibial technique: a comparison with the anteromedial transportal technique.

BACKGROUND Anatomic anterior cruciate ligament (ACL) reconstruction is essential to the restoration of normal knee kinematics and to achieving successful results after ACL surgery. The purpose of this study was to evaluate whether anatomic single-bundle ACL reconstruction can be performed with use of the modified transtibial technique such that the tunnel characteristics are not substantially different from those of the anteromedial transportal technique, with comparable clinical results. METHODS One hundred and four patients underwent single-bundle ACL reconstruction performed with use of either the modified transtibial technique or the anteromedial transportal technique. Each group included fifty-two patients retrospectively matched on the basis of age, sex, and body mass index. All patients had postoperative computed tomography (CT) and a minimum duration of follow-up of twenty-four-months. CT parameters, including tunnel position, tunnel length and shape, and graft obliquity, were evaluated. Clinical assessments were based on manual laxity tests, arthrometric analysis, and clinical scores recorded preoperatively and at the time of follow-up. RESULTS The femoral tunnel was placed at a slightly inferior and anterior position with use of the modified transtibial technique compared with the anteromedial transportal technique, but the difference was not significant (superior-inferior mean [and standard deviation], 35.7% ± 3.1% versus 33.9% ± 4.1%, p > 0.05, and anterior-posterior mean, 31.6 ± 6.8% versus 35.1 ± 6.9%, p > 0.05, as assessed with use of the quadrant method). The femoral tunnel length was significantly longer (p < 0.05) and the tibial tunnel length was significantly shorter (p < 0.05) with use of the modified transtibial technique compared with the anteromedial transportal technique (mean femoral tunnel length, 40.5 ± 4.2 mm versus 34.4 ± 2.6 mm and mean tibial tunnel length, 32.3 ± 3.1 mm versus 35.5 ± 2.7 mm); however, tunnel length was sufficient to allow for adequate fixation. There were no significant differences between the two groups in terms of tibial tunnel position, graft obliquity, tibial tunnel widening, and clinical results. CONCLUSIONS Tunnel characteristics including anatomic position, graft obliquity, and tunnel widening after single-bundle ACL reconstruction performed with use of the modified transtibial technique were not significantly different from those of the anteromedial transportal technique, and clinical results were comparable.

Research trends in biomimetic medical materials for tissue engineering: 3D bioprinting, surface modification, nano/ micro-technology and clinical aspects in tissue engineering of cartilage and bone

This review discusses about biomimetic medical materials for tissue engineering of bone and cartilage, after previous scientific commentary of the invitation-based, Korea-China joint symposium on biomimetic medical materials, which was held in Seoul, Korea, from October 22 to 26, 2015. The contents of this review were evolved from the presentations of that symposium. Four topics of biomimetic medical materials were discussed from different research groups here: 1) 3D bioprinting medical materials, 2) nano/micro-technology, 3) surface modification of biomaterials for their interactions with cells and 4) clinical aspects of biomaterials for cartilage focusing on cells, scaffolds and cytokines.

Novel methods for diagnosis and treatment of posterolateral rotatory instability of the knee

Injury to the posterolateral corner structures of the knee can cause posterolateral rotatory instability, a condition that has attracted increased attention over recent years1. This injury is often associated with cruciate ligament injury, and its diagnosis can be difficult unless one has a high degree of clinical suspicion for an injury to the posterolateral corner structures2,3. Although a number of treatment methods have been proposed over the past twenty years2,4-12, there has been considerable controversy regarding the optimal method of surgical treatment for this injury. The consequences of missed or unsuccessfully treated posterolateral rotatory instability can be profound: reconstructed anterior or posterior cruciate ligaments can fail, and persistent posterolateral rotatory instability may eventually cause pain, instability, and even degenerative changes13-17. In this report, we describe the use of an external rotation-valgus stress radiograph for the evaluation and diagnosis of posterolateral rotatory instability, and we describe a new anatomical reconstruction procedure involving use of a split Achilles tendon allograft for its treatment. ### Background Although several physical examination techniques for the detection of posterolateral rotatory instability of the knee have been described18,19, no widely accepted method of objective documentation, such as the use of posterior stress radiographs to identify a posterior cruciate ligament injury, has been established for posterolateral rotatory instability. Consequently, assessment of posterolateral rotatory instability is very subjective and dependent on the examiners experience. Several biomechanical studies have documented that sectioning of the posterolateral corner structures markedly increases external rotation of the tibia at 30° of knee flexion, whereas sectioning of the posterior cruciate ligament alone does not have the same effect20-22. Consequently, increased external rotation of the tibia relative to the femur at 30° of knee …

Changes in chondrogenic phenotype and gene expression profiles associated with the in vitro expansion of human synovium-derived cells

We undertook this study to characterize changes in the proliferative capacities, chondrogenic phenotypes, and gene expression profiles of human synovium‐derived progenitor cells from osteoarthritic patients during in vitro expansion. Cells isolated from osteoarthritic synovia were cultured, and growth rates during serial passages were evaluated. Surface molecule expressions were determined by flow cytometry and cytogenetic analyses were performed. After chondrogenic differentiation in cell pellets, we evaluated type II collagen and glycosaminoglycan (GAG) synthesis. To assess whether the in vitro expansion of synovium‐derived cells affects gene expression, we performed microarray analyses on cells at passage 0, 1, 2, 4, 6, and 8. Synovium‐derived cells were rapidly expanded in vitro through passage 8 (about 130 days), and after passage 6, the proliferation rates decreased slightly with a wide range of individual variations. The expressions of CD166, CD49a, and CD106 decreased, whereas those of CD10, CD29, CD44, CD73, CD90, and CD105 showed no significant change. Karyotype analysis revealed no evidence of chromosome abnormalities. The staining of type II collagen and GAG in differentiated cell pellets showed rapid weakening. Genome‐wide microarray analysis showed that synovium‐derived cells from late passages over‐expressed genes associated with cell cycle prolongation and cell aging, and less‐expressed genes associated with cell growth stimulation. The in vitro expansion of synovium‐derived cells was accompanied with decreased proliferative capacity and the chondrogenic phenotype, which might be modulated by change in gene expression patterns. Published by Wiley Periodicals, Inc. J Orthop Res 28:1283–1291, 2010