Jun Han

Bio: Jun Han is an academic researcher from Ajou University. The author has contributed to research in topics: Femoral neck & Sarcopenia. The author has an hindex of 7, co-authored 10 publications receiving 150 citations. Previous affiliations of Jun Han include Yanbian University.

Kinematically aligned TKA can align knee joint line to horizontal

Abstract: Purpose The joint line of the native knee is horizontal to the floor and perpendicular to the vertical weight-bearing axis of the patient in a bipedal stance. The purposes of this study were as follows: (1) to find out the distribution of the native joint line in a population of normal patients with normal knees; (2) to compare the native joint line orientation between patients receiving conventional mechanically aligned total knee arthroplasty (TKA), navigated mechanically aligned TKA, and kinematically aligned TKA; and (3) to determine which of the three TKA methods aligns the postoperative knee joint perpendicular to the weight-bearing axis of the limb in bipedal stance.

Sarcopenia and Sarcopenic Obesity in Patients Undergoing Orthopedic Surgery

Abstract: Sarcopenia is a syndrome characterized by progressive and generalized loss of skeletal muscle mass and strength due to senescence, which may lead to physical disability, poor quality of life, and even increased mortality.1) The unprecedentedly rapid aging process in Asian countries has drawn much attention to the geriatric condition.1) Recently, a number of researches have been published on the prevalence and related risk factors of sarcopenia in various cohorts in Asia.2,3,4,5,6,7,8,9) To the best of our knowledge, however, the prevalence of sarcopenia among adults undergoing orthopedic surgery (OS) has never been reported. In the field of OS, bone mineral density (BMD) and bone quality have been the primary focus; however, recent studies have revealed that both bone and muscle are endocrine organs10,11) that are closely associated in both formation and function.12) Moreover, sarcopenia and osteoporosis constitute a hazardous duo that causes frailty in the elderly.13) A recent study has demonstrated the synergistic effects of medications for osteoporosis and mechanical stimuli generated by the muscle, which resulted in the enhanced cortical thickness.14) Such evidence might reveal how sarcopenia adversely affects musculoskeletal health and function in the intraoperative and postoperative settings, especially among the elderly who undergo a number of OS; thus, data on the prevalence of sarcopenia in this population may be invaluable. Moreover, the exact definition of sarcopenia in the orthopaedic field is still debatable, although the European Working Group on Sarcopenia in Older People devised a working clinical definition and consensus-based diagnostic criteria for sarcopenia in 2010.1) According to these criteria, one must have low muscle mass in order to be diagnosed as sarcopenic. However, a variety of methods are currently used to define low muscle mass15,16,17) for orthopedic patients in the absence of any consensus on the ideal criterion of low muscle mass. Recently, the combined impact of muscle loss and fat gain on the functional disability in older persons has been reported,18) and the prevalence of a condition known as sarcopenic obesity has become of great interest. The purpose of this study was to identify the prevalence of sarcopenia and sarcopenic obesity among adult patients who had common OS of specific types, namely intra- and extracapsular proximal femoral fracture surgery and total hip/knee replacement (THR/TKR) and to compare the prevalence of sarcopenia in them with that in nonorthopedic patients at our and other outpatient departments (OPDs).

Combination of measures of handgrip strength and red cell distribution width can predict in-hospital complications better than the ASA grade after hip fracture surgery in the elderly

Abstract: Early detection of a high-risk patient following hip fracture surgery is of paramount clinical importance. American Society of Anesthesiologists (ASA) grading is an easy and efficient index in predicting a worse outcome. The red cell distribution width (RDW) and handgrip strength, are gaining interest as a prediction tool as well. Accordingly, the objective of this study was to investigate the potential association between ASA, RDW and grip strength and detect the effects of combining RDW and grip strength for predicting early complication after hip fracture surgery in the elderly. Eighty-three consecutive patients operated with hip fracture surgeries were identified retrospectively. Age, gender, diagnosis, RDW, handgrip strength and ASA grade were recorded. Admission to the intensive care unit (ICU), length of ICU stay, transfer to other departments, in-hospital death, and readmission were investigated as early complications. Logistic regression analysis was applied to evaluate the estimates in predicting complications, and receiver operating characteristics curves were constructed to compare the estimates and decide which method is more accurate. After the surgery, 52% of the patients were admitted to the ICU. From the analyses, RDW and grip strength had no significant relation with each other. However, the ICU stay was correlated with RDW and grip strength but not for the ASA grade. A higher ASA grade and grip strength could independently predict ICU admission. The combination of RDW with grip strength outweighed the ASA grade in predictive ability. The current study indicated that combining RDW and grip strength measures can be efficient and clinically relevant in predicting early postoperative complications after fragility hip fracture in the elderly. Due to the objectivity and availability of those two approaches, patient care, and functional outcomes are expected to be improved by adopting these measures in the clinical setting.

Proximal Femoral Geometry as Fracture Risk Factor in Female Patients with Osteoporotic Hip Fracture

Abstract: BACKGROUND Proximal femoral geometry may be a risk factor of osteoporotic hip fractures. However, there existed great differences among studies depending on race, sex and age of subjects. The purpose of the present study is to analyze proximal femoral geometry and bone mineral density (BMD) in the osteoporotic hip fracture patients. Furthermore, we investigated proximal femoral geometric parameters affecting fractures, and whether the geometric parameters could be an independent risk factor of fractures regardless of BMD. METHODS This study was conducted on 197 women aged 65 years or more who were hospitalized with osteoporotic hip fracture (femur neck fractures ; 84, intertrochanteric fractures; 113). Control group included 551 women who visited to check osteoporosis. Femur BMD and proximal femoral geometry for all subjects were measured using dual energy X-ray absorptiometry (DXA), and compared between the control and fracture groups. Besides, proximal femoral geometric parameters associated with fractures were statistically analyzed. RESULTS There were statistically significant differences in the age and weight, cross-sectional area (CSA)/length/width of the femoral neck and BMD of the proximal femur between fracture group and control group. BMD of the proximal femur in the control group was higher than in the fracture group. For the femoral neck fractures group, the odds ratio (OR) for fractures decrease in the CSA and neck length (NL) of the femur increased by 1.97 times and 1.73 times respectively, regardless of BMD. The OR for fractures increase in the femoral neck width increased by 1.53 times. In the intertrochanteric fracture group, the OR for fractures increase in the femoral neck width increased by 1.45 times regardless of BMD. CONCLUSIONS We found that an increase of the femoral neck width could be a proximal femoral geometric parameter which plays important roles as a risk factor for fracture independently of BMD.

Sarcopenia and Osteoporosis.

Abstract: Public health strategies designed to accomodate the ever-increasing human lifespan are urgently required. A good clinical understanding of frailty, as well as knowledge regarding how to prevent it, will therefore be required in order to overcome this challenge. Sarcopenia is an important component of the frailty syndrome, and its association with osteoporosis can lead to fractures and incident disability. Therefore, this review examined the literatuire pertaining to the association of sarcopenia with osteoporosis in order to assess preventive strategies.

Implant Survival and Function Ten Years After Kinematically Aligned Total Knee Arthroplasty

Abstract: Background Alignment in the varus or valgus outlier range of the tibial component, knee, and limb might adversely affect the long-term results of kinematically aligned total knee arthroplasty (TKA) particularly when patients are selected without restricting the degree of preoperative varus-valgus and flexion deformity. Methods A retrospective review of all patients treated in 2007 with a primary TKA determined the 10-year implant survivorship, yearly revision rate, Oxford Knee Score, and WOMAC. All 222 knees (217 patients) were aligned kinematically using patient-specific instrumentation without restricting the degree of preoperative deformity and with the restoration of the native joint lines and limb alignment. Mechanical alignment criteria categorized the alignments of the tibial component, knee, and limb as in-range or in a varus or valgus outlier range. Results The implant survivorship (yearly revision rate) was 97.5% (0.3%) for revision for any reason and 98.4% (0.2%) for aseptic failure. The percentage postoperatively aligned in the varus outlier (valgus outlier) range was 78% (0%) for the angle between the tibial component and mechanical axis of the tibia, 31% (5%) for the tibiofemoral angle of the knee according to the criteria by Ritter et al, and 7% (21%) for the hip-knee-ankle angle of the limb according to the criteria by Parratte et al. Patients grouped in the varus outlier range, valgus outlier range, and in-range had similar implant survival and function scores. The 10-year Oxford Knee Score (48 best) and WOMAC (0 best) averaged 43 and 7 points, respectively. Conclusion With the limitation that a large case series unlikely represents the full range of preoperative deformities and native alignments, treatment of patients with kinematically aligned TKA with patient-specific instrumentation without restricting the preoperative deformity did not adversely affect the 10-year implant survival, yearly revision rate, and level of function. Level of evidence Level III, therapeutic study.

Current state of computer navigation and robotics in unicompartmental and total knee arthroplasty: a systematic review with meta-analysis.

Abstract: Recently, there is a growing interest in surgical variables that are intraoperatively controlled by orthopaedic surgeons, including lower leg alignment, component positioning and soft tissues balancing. Since more tight control over these factors is associated with improved outcomes of unicompartmental knee arthroplasty and total knee arthroplasty (TKA), several computer navigation and robotic-assisted systems have been developed. Although mechanical axis accuracy and component positioning have been shown to improve with computer navigation, no superiority in functional outcomes has yet been shown. This could be explained by the fact that many differences exist between the number and type of surgical variables these systems control. Most systems control lower leg alignment and component positioning, while some in addition control soft tissue balancing. Finally, robotic-assisted systems have the additional advantage of improving surgical precision. A systematic search in PubMed, Embase and Cochrane Library resulted in 40 comparative studies and three registries on computer navigation reporting outcomes of 474,197 patients, and 21 basic science and clinical studies on robotic-assisted knee arthroplasty. Twenty-eight of these comparative computer navigation studies reported Knee Society Total scores in 3504 patients. Stratifying by type of surgical variables, no significant differences were noted in outcomes between surgery with computer-navigated TKA controlling for alignment and component positioning versus conventional TKA (p = 0.63). However, significantly better outcomes were noted following computer-navigated TKA that also controlled for soft tissue balancing versus conventional TKA (mean difference 4.84, 95 % Confidence Interval 1.61, 8.07, p = 0.003). A literature review of robotic systems showed that these systems can, similarly to computer navigation, reliably improve lower leg alignment, component positioning and soft tissues balancing. Furthermore, two studies comparing robotic-assisted with computer-navigated surgery reported superiority of robotic-assisted surgery in controlling these factors. Manually controlling all these surgical variables can be difficult for the orthopaedic surgeon. Findings in this study suggest that computer navigation or robotic assistance may help managing these multiple variables and could improve outcomes. Future studies assessing the role of soft tissue balancing in knee arthroplasty and long-term follow-up studies assessing the role of computer-navigated and robotic-assisted knee arthroplasty are needed.

Patellar height and posterior tibial slope after open and closed wedge high tibial osteotomy

Abstract: Valgus high tibial osteotomy (HTO) results in changes in the frontal as well as sagittal planes. Our hypothesis suggests that patellar height increases and posterior tibial inclination decreases after closed wedge (cw) HTO, whereas patellar height decreases and tibial slope increases after open wedge (ow) HTO. Lateral radiographs of 100 knees were assessed for patellar height (PH) using Insall-Salvati (ISI), Caton-De Champ (CDI) and Blackburne-Peel indices (BPI) as well as posterior tibial slope. Measurements were done before HTO (50 cw and 50 ow), direct postoperatively and before hardware removal. In the cw-group all three PH indices increased direct postoperatively and at removal of the hardware with changes in CDI and BPI being significant (P 0.05). Posterior tibial slope showed a significant decrease of 3.1 ± 3.4° after closed wedge HTO and a significant increase of 2.1 ± 3.6° after ow HTO direct postoperatively. In cw-HTO the correlations between frontal plane correction and PH changes were moderate (CDI: r = 0.57; BPI: r = 0.64). In ow-HTO these correlations were weak (CDI: r = 0.44; BPI: r = 0.46). According to ISI there was no correlation (cw: r = 0.11; ow: r =0.16). There was no correlation between PH changes according to CDI and slope changes. The incidence of patella infera increases after open wedge HTO, whereas the incidence of patella alta increases after closed wedge HTO. We recommend considering the PH and tibial slope before planning for HTO or TKR after HTO, also performing cw-HTO or ow-HTO with the tuberosity left at the proximal tibia in cases of patellofemoral complaint or patella infera.

Kinematic alignment is a possible alternative to mechanical alignment in total knee arthroplasty

Abstract: A systematic review was conducted to answer the following questions: (1) Does kinematically aligned (KA) total knee arthroplasty (TKA) achieve clinical outcomes comparable to those of mechanically aligned (MA) TKA? (2) How do the limb, knee, and component alignments differ between KA and MA TKA? (3) How is joint line orientation angle (JLOA) changed from the native knee in KA TKA compared to that in MA TKA? Nine full-text articles in English that reported the clinical and radiological outcomes of KA TKA were included. Five studies had a control group of patients who underwent MA TKA. Data on patient demographics, clinical scores, and radiological results were extracted. There were two level I, one level II, three level III, and three level IV studies. Six of the nine studies used patient-specific instrumentation, one study used computer navigation, and two studies used manual instrumentation. The clinical outcomes of KA TKA were comparable or superior to those of MA TKA with a minimum 2-year follow-up. Limb and knee alignment in KA TKA was similar to those in MA TKA, and component alignment showed slightly more varus in the tibial component and slightly more valgus in the femoral component. The JLOA in KA TKA was relatively parallel to the floor compared to that in the native knee and not oblique (medial side up and lateral side down) compared to that in MA TKA. The implant survivorship and complication rate of the KA TKA were similar to those of the MA TKA. Similar or better clinical outcomes were produced by using a KA TKA at early-term follow-up and the component alignment differed from that of MA TKA. KA TKA seemed to restore function without catastrophic failure regardless of the alignment category up to midterm follow-up. The JLOA in KA TKA was relatively parallel to the floor similar to the native knee compared to that in MA TKA. The present review of nine published studies suggests that relatively new kinematic alignment is an acceptable and alternative alignment to mechanical alignment, which is better understood. Further validation of these findings requires more randomized clinical trials with longer follow-up. Level II.

Does Calipered Kinematically Aligned TKA Restore Native Left to Right Symmetry of the Lower Limb and Improve Function

Abstract: Background Kinematically aligned total knee arthroplasty (KA TKA) strives to restore the native left to right symmetry of the lower limb; however, the reproducibility of achieving this target is unknown. The present study determined the proportion of patients with left to right symmetry and the improvement in patient-reported function after calipered KA TKA. Methods A review of 562 postoperative scanograms identified 102 patients (53 women) with a KA TKA in one limb, no other skeletal abnormalities in either limb, and symmetrical rotation between limbs on the scanogram. All patients were treated with primary TKA that used caliper measurement of the thicknesses of the femoral bone and tibial bone resections to kinematically align the components. The hip-knee-ankle (HKA) angle, distal lateral femoral angle (DLFA), and proximal medial tibial angle (PMTA) were measured. Patient-reported Oxford Knee Score (OKS) measured preoperative and postoperative functions. Results The proportion of patients with a difference in the HKA angle, DLFA, and PMTA between limbs within ±3°, >3° varus, and Conclusion Calipered KA TKA restored native left to right symmetry of the HKA angle, DLFA, and PMTA in nearly all patients with negligible risk of varus alignment of the tibial component with respect to the native tibial joint line. The mean postoperative OKS indicated clinically important improvement in patient-reported function.