Cohort profile: the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS) in Korea.

PURPOSE: The National Health Insurance Service-Health Screening Cohort (NHIS-HEALS) is a cohort of participants who participated in health screening programmes provided by the NHIS in the Republic of Korea. The NHIS constructed the NHIS-HEALS cohort database in 2015. The purpose of this cohort is to offer relevant and useful data for health researchers, especially in the field of non-communicable diseases and health risk factors, and policy-maker. PARTICIPANTS: To construct the NHIS-HEALS database, a sample cohort was first selected from the 2002 and 2003 health screening participants, who were aged between 40 and 79 in 2002 and followed up through 2013. This cohort included 514 866 health screening participants who comprised a random selection of 10% of all health screening participants in 2002 and 2003. FINDINGS TO DATE: The age-standardised prevalence of anaemia, diabetes mellitus, hypertension, obesity, hypercholesterolaemia and abnormal urine protein were 9.8%, 8.2%, 35.6%, 2.7%, 14.2% and 2.0%, respectively. The age-standardised mortality rate for the first 2 years (through 2004) was 442.0 per 100 000 person-years, while the rate for 10 years (through 2012) was 865.9 per 100 000 person-years. The most common cause of death was malignant neoplasm in both sexes (364.1 per 100 000 person-years for men, 128.3 per 100 000 person-years for women). FUTURE PLANS: This database can be used to study the risk factors of non-communicable diseases and dental health problems, which are important health issues that have not yet been fully investigated. The cohort will be maintained and continuously updated by the NHIS.

Different intraoperative kinematics with comparable clinical outcomes of ultracongruent and posterior stabilized mobile-bearing total knee arthroplasty.

PURPOSE: There remains no consensus as to whether mobile total knee arthroplasty (TKA) should use a posterior cruciate ligament-sacrificing ultracongruent (UC) or a posterior cruciate ligament-substituting posterior stabilized (PS) prosthesis. The purpose of this study was to assess intraoperative kinematics and clinical outcomes of UC and PS rotating platform mobile-bearing TKA. METHODS: In this randomized controlled study, mobile UC TKA prostheses (n = 45) were compared with mobile PS TKA prostheses (n = 45) with regard to intraoperative kinematics and clinical outcomes. The passive kinematic study using intraoperative navigation system included anterior/posterior translation, varus/valgus alignment and rotation of femur during flexion. The patients were clinically and radiographically evaluated over a 3-year follow-up. RESULTS: Paradoxical anterior translation of the femur was 10.8 ± 5.2 mm in the UC knee from 0° to 82° of knee flexion and 8.7 ± 3.0 mm in the PS knee from 0° to 70° of knee flexion (p = 0.027). Paradoxical internal rotation of the femur was 5.8° in the UC knees and 9.9° in the PS knees (p = 0.003). But, there was no significant difference between the groups in regard to the coronal alignment. There was no significant difference in the range of motion, KS knee scores, KS function scores, and WOMAC index scores. CONCLUSIONS: Despite different intraoperative kinematics between mobile UC and mobile PS TKA, neither design reproduced physiologic knee kinematics and there was no difference in clinical outcomes between the two groups. The clinical relevance of the study is that despite different intraoperative kinematics, UC design can be a considerable alternative to PS design in mobile-bearing TKA in respect of clinical outcomes. LEVEL OF EVIDENCE: II.

Which analgesic mixture is appropriate for periarticular injection after total knee arthroplasty? Prospective, randomized, double-blind study.

PURPOSE: Although the analgesic effect of periarticular injection after total knee arthroplasty (TKA) has been well documented, the gold standard for drug combination has not yet been established. In this study, the analgesic effects of six different drug combinations were compared. METHODS: A total of 256 patients undergoing TKA for primary osteoarthritis were randomized into one of six groups: a control group (saline solution, epinephrine, and cefazolin, n = 42), Group 1 (ropivacaine, n = 43), Group 2 (ropivacaine + morphine, n = 43), Group 3 (ropivacaine + ketorolac, n = 42), Group 4 (ropivacaine + morphine + ketorolac, n = 43), and Group 5 (ropivacaine + morphine + ketorolac + methylprednisolone, n = 43). Pain level assessed by visual analogue scale (VAS) and opioid consumption were primary outcomes. The incidence of complications, range of motion (ROM), C-reactive protein (CRP) value, and the amount of post-operative blood drainage were also compared. RESULTS: Patients in Groups 4 and 5 complained less pain than the control group for the first 12 h after surgery, and the patients in the other groups showed less pain only during the initial 6 h after surgery. Groups 4 and 5 also showed less opioid consumption than the control group during the 24 h period after surgery. Patients in Group 5 showed no significant difference in VAS score and opioid consumption compared with Group 4, but they had lower CRP value and greater ROM than any other groups at post-operative day 2 and day 4. CONCLUSION: The combination of ropivacaine, morphine, and ketorolac showed a significantly stronger and sufficiently synergistic analgesic effect without adding methylprednisolone in periarticular injection after TKA. The clinical relevance of the study is that the combination of ropivacaine, morphine, and ketorolac can be a good option for periarticular injection following TKA in terms of synergistic analgesic effect and efficiency of drug combination.

Anatomy of the anterior cruciate ligament insertion sites: comparison of plain radiography and three-dimensional computed tomographic imaging to anatomic dissection.

PURPOSE: The aim of this study was to provide quantitative data on insertion sites of anterior cruciate ligament (ACL) and to assess the correlation among measurements of anatomic dissection, plain radiographs, and 3D CT images to determine whether radiologic data can accurately reflect real anatomic measurements. METHODS: Fifteen cadaveric knees were assessed using the three measurement modalities. Lengths of the long and short axis, area, and centre position of each bundle insertion sites by quadrant method were examined on both the femur and tibia. Distances from the insertion centre to distal cortical and posterior cortical margins of condyle on femur, and distance between insertion centres on tibia were also inspected. RESULTS: The average ACL insertion position in the three measurement modalities was at 33.9 % in deep-shallow position and at 26.5 % in high-low position for anteromedial (AM) bundle and at 39.2 and 54.8 %, respectively, for posterolateral (PL) bundle in femur. For tibia, it was at 36.9 % in anterior-posterior position and 47.1 % in medial-lateral position for AM bundle and at 43.1 and 53.5 %, respectively, for PL bundle. The slight differences in various measurements among the three modalities were not statistically significant. CONCLUSIONS: The femoral insertion positions were considerably shallow and low, whereas tibial insertion positions were near the average compared to those in previous studies. Plain radiographic and 3D CT measurements showed a reliable correlation with anatomic dissection measurements. The clinical relevance is that plain radiographs rather than 3D CT can be used as a post-operative evaluation tool after ACL reconstruction.

Prevalence of osteoporosis in female patients with advanced knee osteoarthritis undergoing total knee arthroplasty.

This study sought to demonstrate bone mineral density (BMD) conditions in elderly female patients with knee osteoarthritis (OA) undergoing total knee arthroplasty (TKA). In addition, we sought to determine whether their BMD conditions differ from those of community-based females without knee OA. Finally we sought to determine whether clinical statuses are related to BMD in the knee OA patients. BMD conditions in 347 female patients undergoing TKA and 273 community-based females were evaluated. Additionally, comparative analyses of BMD between age and body mass index-matched knee OA groups (n=212) and the control groups (n=212) were performed. In the pre-matched knee OA group, regression analyses were performed to determine whether preoperative clinical statuses were related to BMD. Considerable prevalence of coexistent osteoporosis (31%) was found in the pre-matched knee OA patients undergoing TKA. We found no significant differences of the BMD T-scores and the prevalence of osteoporosis between the age and body mass index-matched knee OA and control groups. In the pre-matched knee OA patients, poorer preoperative clinical scores were related to poorer BMD T-scores in the proximal femur and/or lumbar spine. Our study suggests that more attention should be paid to identify and treat osteoporosis in elderly female patients with advanced knee OA undergoing TKA.

The effect of platelet-rich plasma on the differentiation of synovium-derived mesenchymal stem cells.

Platelet-rich plasma (PRP), the plasma portion of blood with a high platelet concentration, has been reported to be helpful in stem cell chondrogenesis due to large amount of growth factors it contains. Here, we examined the influence of PRP on the differentiation of synovium-derived stem cells (SDSCs) and also evaluated if PRP alone was sufficient to induce SDSCs differentiation. First, the cell proliferation in various differentiation media was analyzed using the MTT assay and it was significantly higher in groups cultured with media that contained PRP. Then, We performed Safranin-O staining and type I, II, and X collagen immunohistochemistry (chondrogenesis), von Kossa staining (osteogenesis), and Oil Red O staining (adipogenesis). The staining was most prominent in groups cultured with optimized differentiation media without PRP in all three lineages of differentiation. The mRNA expression levels of typical differentiation markers were also analyzed using reverse transcription quantitative polymerase chain reaction. Although, culture in optimized differentiation media increased the mRNA expression of the typical differentiation marker genes, they were significantly reduced when cultured in the media supplemented with PRP. PRP has negative effects on SDSC differentiation in all three differentiation lineages and PRP alone does not induce SDSC differentiation.

Effects of CD14 macrophages and proinflammatory cytokines on chondrogenesis in osteoarthritic synovium-derived stem cells.

We investigated the effects of CD14 macrophages and proinflammatory cytokines on chondrogenic differentiation of osteoarthritic synovium-derived stem cells (SDSCs). Osteoarthritic synovial fluid was analyzed for interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), and IL-6. Levels of stem cell surface markers in osteoarthritic SDSCs were evaluated using flow cytometry. CD14-negative cells were obtained using magnetically activated cell sorting. We compared chondrogenic potentials between whole cells and CD14-negative cells in CD14(low) cells and CD14(high) cells, respectively. To assess whether nuclear factor-κB (NF-κB) and CCAAT/enhancer-binding protein ß (C/EBPß) modulate IL-1ß-induced alterations in chondrogenic potential, we performed small interfering RNA transfection. We observed a significant correlation between the CD14 ratio in osteoarthritic SDSCs and IL-1ß and TNF-α in osteoarthritic synovial fluid. Phenotypic characterization of whole cells and CD14-negative cells showed no significant differences in levels of stem cell markers. mRNA expression of type II collagen was higher in CD14-negative cell pellets than in whole cell pellets. Immunohistochemical staining indicated higher levels of type II collagen in the CD14-negative cell pellets of CD14(high) cells than in whole cell pellets of CD14(high) cells. As expected, IL-1ß and TNF-α significantly inhibited the expression of chondrogenic-related genes in SDSCs, an effect which was antagonized by knockdown of NF-κB and C/EBPß. Our results suggest that depletion of CD14(+) synovial macrophages leads to improved chondrogenic potential in CD14(high) cell populations in osteoarthritic SDSCs, and that NF-κB (RelA) and C/EBPß are critical factors mediating IL-1ß-induced suppression of the chondrogenic potential of human SDSCs.

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.

Modified Transtibial Technique for Anterior Cruciate Ligament Reconstruction with Quadriceps Tendon Autograft.

INTRODUCTION: The modified transtibial technique with quadriceps tendon autograft allows anatomic anterior cruciate ligament (ACL) reconstruction without tunnel widening and results in a stable and functional knee with a satisfactory clinical outcome. STEP 1 PREPARE THE PATIENT: Prepare the patient under spinal anesthesia with the usual arthroscopic setting. STEP 2 ARTHROSCOPIC EXAMINATION: Perform arthroscopic examination to confirm the ACL rupture and other intra-articular lesions. STEP 3 HARVEST THE QUADRICEPS TENDON: Harvest the central one-third of the quadriceps tendon strip with a proximal patellar bone block. STEP 4 PREPARE THE QUADRICEPS TENDON GRAFT: Prepare the quadriceps tendon graft to pass smoothly through the tunnels. STEP 5 SET THE TIBIAL TUNNEL ENTRY POINT: Make a 3-cm longitudinal skin incision at the anteromedial aspect of the proximal part of the tibia. STEP 6 CREATE THE TIBIAL TUNNEL: Drill a 10-mm tibial tunnel. STEP 7 TARGET THE FEMORAL TUNNEL STARTING POINT: Aim the guide at the lateral bifurcate ridge on the medial wall of the lateral femoral condyle with the modified transtibial technique. STEP 8 CREATE THE FEMORAL TUNNEL: Drill a 10-mm femoral tunnel. STEP 9 FIX THE GRAFT: Fix the graft with adequate tension. STEP 10 POSTOPERATIVE REHABILITATION: Rehabilitate the patient step by step. RESULTS: In a study that compared fifty-two patients managed with a modified transtibial technique and another fifty-two patients managed with an anteromedial transportal technique, there were no significant differences in the clinical results in terms of manual laxity, arthrometric analysis, and subjective outcome.IndicationsContraindicationsPitfalls & Challenges.

Is TKA using patient-specific instruments comparable to conventional TKA? A randomized controlled study of one system.

BACKGROUND: Patient-specific CT-based instrumentation may reduce implant malpositioning and improve alignment in TKA. However, it is not known whether this innovation is an advance that benefits patients. QUESTIONS/PURPOSES: We evaluated (1) the precision of patient-specific TKA by comparing the incidence of outliers in postoperative alignment between TKAs using patient-specific instruments and TKAs using conventional instruments, and (2) the reliability of patient-specific instruments by intraoperatively investigating whether the surgery could be completed with patient-specific instruments alone. METHODS: In this randomized controlled trial, we compared patient-specific TKA instruments from one manufacturer (n = 50) with conventional TKA instruments (n = 50). Postoperative hip-knee-ankle angles, femoral component rotation, and coronal and sagittal alignments of each component were measured. The validity of the patient-specific instrument was examined using cross-checking procedures with conventional instruments during the surgeries. When the procedure could not be completed accurately with patient-specific instruments, the procedure was converted to TKA using conventional instruments, and the frequency of this occurrence was tallied. RESULTS: Outliers in the hip-knee-ankle angle were comparable between groups (12% in the patient-specific instrument group and 10% in the conventional instrument group). Other parameters such as sagittal alignment and femoral component rotation did not differ in terms of outliers. Patient-specific guides were abandoned in eight knees (16%) during the surgery because of malrotation of the femoral components and decreased slope of the tibia. CONCLUSIONS: Accuracy was comparable between TKAs done with patient-specific instruments and those done with conventional instruments. However, the patient-specific instrument procedures had to be aborted frequently, incurring expenses that did not benefit patients.

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.

The patterns of limb length, height, weight and body mass index changes after total knee arthroplasty.

The objective of this retrospective review of 466 patients was to document changes in limb length, leg length discrepancy (LLD), height, weight, and body mass index (BMI) 1 year after TKA and the patterns of height, weight, and BMI during 5 years. To determine change patterns over 5 years, the data of 291 patients were analyzed and compared with those of age and gender-matched normal subjects. Limb length, height, and weight increased, BMI remained unchanged, and LLD decreased 1 year after TKA. The bilateral group had a greater height increase and lower rate of LLD. Preoperative mechanical tibiofemoral angle was related to limb length increase, and patients with a smaller preoperative BMI showed more weight gain. During the 5 years, weight and BMI at 1 year were maintained, but height diminished, while the healthy population showed a decreasing trend in weight.

Effect of chondroitinase ABC on adhesion and behavior of synovial membrane-derived mesenchymal stem cells in rabbit partial-thickness chondral defects.

Transplanted cells may have difficulty attaching to the surface of partial-thickness chondral lesions because of the anti-adhesive properties of the proteoglycan rich matrix. Therefore, the current study attempts to evaluate the effect of chondroitinase ABC (chABC) on the adhesion and behavior of transplanted synovial membrane-derived mesenchymal stem cells (SDSCs) in rabbit partial-thickness chondral defects. In ex vivo adhesion experiments, chABC treatment (0.1 U/ml) was increased in SDSC attachment to the cartilage explants, and significantly diminished by pretreatment with neutralizing antibody against fibronectin. In the in vivo experiments, 1 day and 4 weeks after the chABC treatment (0.1 and 1 U/ml), the immunoreactivity (IR) against CS-56 (intact chondroitin sulfate antibody) was markedly decreased; however, the IR of 2B6 (stub of the chondroitin 4-sulfate chain), 3B3 (stub of the chondroitin 6-sulfate chain), and fibronectin was increased. At 12 weeks, this IR returned to normal except in the high-dose chABC-treated group (1 U/ml). Furthermore, the attachment of SDSCs to the chondral defects after chABC treatment was increased at 7 days compared with that in the chondral defects pretreated with saline. However, the tissue repaired by SDSCs was negatively stained for type II collagen at 12 weeks. In conclusion, these results showed that the exposure to fibronectin by chABC treatment enhances the attachment of SDSCs to partial-thickness chondral defects. However, the tissue regenerated by SDSCs showed lack of hyaline cartilage regeneration. Thus, to understand the fate of transplanted MSCs in cartilage defect is very important for successful cell therapies.

Preservation of the posterior cruciate ligament is not helpful in highly conforming mobile-bearing total knee arthroplasty: a randomized controlled study.

PURPOSE: The purpose of this study is to investigate whether the preservation of the posterior cruciate ligament (PCL) can be helpful for improving kinematics and clinical outcome in highly conforming mobile-bearing total knee arthroplasty (TKA). METHODS: Ninety osteoarthritic knees were randomly allocated to either the PCL-preserving group or the PCL-sacrificing group. Passive kinematics was recorded with a navigation system immediately after implantation. Three parameters (anterior/posterior translation, varus/valgus rotation, and internal/external rotation) were analysed from 0° to 120° flexion. RESULTS: The PCL-preserving group (42 knees) had more varus rotation over 90° flexion (p < 0.05) and more anterior translation of the femur in all ranges of flexion (p < 0.05) than those in the PCL-sacrificing group (44 knees). There was no difference in the internal/external rotation (p > 0.05). The range of motion, functional scores, and radiographic results did not significantly differ between the two groups at the final follow-up. Three knees in the PCL-preserving group were revised: two presented with instability caused by traumatic attenuation of the PCL and one with subluxation of the insert due to a tight PCL. CONCLUSION: The preservation of the PCL was not helpful for improving kinematics and clinical outcome in highly conforming mobile-bearing TKA.

Incidence, predictors, and effects of residual flexion contracture on clinical outcomes of total knee arthroplasty.

Patients who present with large flexion contracture (FC) but have well maintained maximum flexion tend to have a flexion-extension gap mismatch, which can cause residual FC or flexion instability after TKA. We routinely use posterior-stabilized implants, perform soft tissue balancing and additional distal femur resection, and determine the polyethylene insert thickness based on flexion-extension gap difference to avoid postoperative FC and flexion instability. We retrospectively reviewed 911 TKAs performed with this protocol to determine the incidence, predictors and effects of postoperative FC on clinical outcomes. Knees with postoperative FC ≥10° were identified, and their clinical outcomes were compared with knees without FC. The average follow-up period was 35months (range, 24-72months). Eighteen (2.0%) of the 911 knees presented with postoperative FC. The occurrence of postoperative FC was associated with preoperative FC and anterior knee pain, but not with a flexion-extension gap mismatch. A mild to moderate postoperative FC does not increase pain, but may be detrimental to quality of life.

Painful patellar clunk or crepitation of contemporary knee prostheses.

BACKGROUND: Painful patellar clunk or crepitation (PCC) is a resurgent complication of contemporary posterior-stabilized TKA. The incidence, time to presentation, causes, and treatment of PCC still remain controversial. QUESTIONS/PURPOSES: We therefore (1) compared the incidence of PCC with five contemporary TKA designs, (2) evaluated the time to presentation, (3) identified possible etiologies, and (4) determined recurrence rate and change in knee functional scores after treatment for PCC. METHODS: We reviewed 580 patients who had 826 posterior-stabilized TKAs involving five different designs. The incidences of PCC were compared among the prostheses. The knees were divided into two groups depending on the development of PCC, and possible etiologic factors of PCC, including prosthesis design and surgical or radiographic variables, were compared between groups. We investigated the onset time of PCC and evaluated treatment results by knee outcome scores. Minimum followup was 2.0 years (mean, 3.9 years; range, 2.0-9.8 years). RESULTS: The PCC incidence was higher in the Press-Fit Condylar(®) Sigma(®) Rotating Platform/Rotating Platform-Flex Knee System (11 of 113 knees, 9.7%) than in the others (seven of 713 knees, 1.0%). Increased risk of PCC was associated with using a specific prosthesis and patellar retention. PCC occurred in all cases within a year after TKA (mean, 7.4 months). Arthroscopic treatment (16 knees) and patellar replacement (two knees) improved knee scores, with no recurrence observed over an average followup of 29 months. CONCLUSIONS: Prosthesis design and patellar retention were associated with PCC. Surgery resolved the PCC.

Revision total knee arthroplasty with varus-valgus constrained prosthesis versus posterior stabilized prosthesis.

PURPOSE: The aims of this retrospective study were to provide the basis for the choice of prosthesis in revision total knee arthroplasty (TKA) and to evaluate the outcome with varus-valgus constrained prosthesis compared with posterior stabilized (PS) prosthesis. METHODS: One hundred and five patients (121 knees) received revision TKA; of which thirty-seven patients (42 knees) received PS prosthesis and sixty-eight patients (79 knees) received varus-valgus constrained prosthesis. The mean follow-up duration was 64.8 ± 31.5 months and 63.2 ± 28.1 months in the PS and varus-valgus constrained groups, respectively. The criterion of prosthesis choice was a subjective laxity assessed by the surgeon intraoperatively. A multivariate analysis was performed to evaluate the preoperative factors in the choice of the prosthesis. RESULTS: The grade of femoral bone defect was the only factor that affected the choice of prosthesis. Clinical results improved significantly in both groups after surgery. There were no significant differences in clinical results between the two groups. Complication rates were 9.5 % in the PS group and 10.1 % in the varus-valgus constrained group, and the Kaplan-Meier survivorship analysis revealed 8-year component survival rates of 83.1 and 93.0 % in the PS and varus-valgus constrained groups, respectively. CONCLUSIONS: Femoral bone defect is an important factor to be considered in the choice of prosthesis for revision TKA. The varus-valgus constrained prosthesis showed an outcome similar to that of the PS prosthesis. For clinical relevance, varus-valgus constrained prosthesis is recommended in revision TKA when the PS prosthesis seems unsuitable for the management of instability. LEVEL OF EVIDENCE: III.

Outcomes of the different types of total knee arthroplasty with the identical femoral geometry.

PURPOSE: There are controversies around the role of the posterior cruciate ligament and the effect of design modifications for high flexion in total knee arthroplasty (TKA). So, we compared the clinical outcomes of the cruciate retaining (CR), posterior stabilized (PS), and high flexion posterior stabilized (F-PS) designs in TKA with identical femoral geometry. MATERIALS AND METHODS: One hundred seventy nine knees with 3 different types of prostheses after a minimum 5-year follow-up were enrolled in this retrospective study: 45 with CR, 40 with PS and 94 with F-PS. The mean ages of these groups were 65.7, 67.2, and 67.5, and the mean durations of follow-up were 8.1, 8.0, and 6.8 years, respectively. We compared the range of motion, functional outcomes, and radiographic measurements at the 2-year follow-up and last follow-up. RESULTS: The maximal flexion angle was significantly lower in the CR group than the F-PS group at the 2-year follow-up. However, there was no significant difference at the last follow-up. Functional outcomes and survival rate of the three groups were similar at the last follow-up. CONCLUSIONS: Three different types of TKAs (CR, PS and F-PS) with identical femoral geometry showed similar mid-term outcomes with regard to the range of motion, functional outcomes and survival rate.

Synovium-derived mesenchymal stem cells encapsulated in a novel injectable gel can repair osteochondral defects in a rabbit model.

We developed a novel injectable type I collagen/hyaluronic acid/fibrinogen (COL/HA/FG) composite gel that encapsulated synovium-derived mesenchymal stem cells (SDSCs) for the repair of damaged articular cartilage. We first analyzed the suitability of the composite gel as a three-dimensional injectable cell carrier in vitro. In an in vivo rabbit model, the COL/HA/FG composite gel displayed the potential to regenerate and repair osteochondral defects in the knee. Culture of the SDSCs encapsulated COL/HA/FG composite gel in a chondrogenic medium resulted in high viability of the SDSCs and high expressions of type II collagen, aggrecan, and sox 9 mRNA. Moreover, glycosaminoglycans and type II collagen were accumulated within the extracellular matrix. In the animal model, the SDSCs encapsulated COL/HA/FG composite gel produced a hyaline-like cartilage construct. Twenty-four weeks after transplantation, the defects had been repaired with hyaline cartilage-like tissue that was densely stained by safranin-O and immunostained by a type II collagen antibody. This data suggest that the SDSC-encapsulated COL/HA/FG composite gel can be a good therapeutic candidate/strategy for repairing of damaged articular cartilage.

Intraoperative correlation analysis between tunnel position and translational and rotational stability in single- and double-bundle anterior cruciate ligament reconstruction.

PURPOSE: To determine the relation between the tunnel positions and the kinematic improvement of the knee joint after single-bundle (SB) and double-bundle (DB) anterior cruciate ligament (ACL) reconstructions. METHODS: The study included 42 patients who underwent either SB (n = 21) or DB (n = 21) ACL reconstruction using hamstring tendon autograft. Anterior tibial translation and rotational laxity were measured by a navigation system before and after graft fixation. Three-dimensional computed tomography measurement was conducted for evaluation of tunnel placements. Regression analysis was carried out to determine the association between the postoperative kinematic change and the tunnel position. RESULTS: The average tunnel location was mostly different between the SB and posterolateral bundle (PLB) tunnels, as well as between the anteromedial bundle (AMB) and PLB tunnels of DB ACL reconstructions, whereas the SB and AMB tunnels were similar in the tibial mediolateral and femoral deep-shallow positions. A regression curve showed that the PLB femoral tunnel position was correlated with rotation whereas both the SB and AMB femoral tunnel locations were mostly correlated with anterior tibial translation. CONCLUSIONS: The PLB tunnel location in DB ACL reconstruction had a considerable effect on rotational laxity, whereas the SB and AMB tunnel locations mostly influenced anterior tibial translation. LEVEL OF EVIDENCE: Level III, case-control study.