Hip displacement, common in patients with cerebral palsy (CP), causes pain and hinders adequate care. Hip reconstructive surgery (HRS) is performed to treat hip displacement; however, only a few studies have quantitatively assessed femoral head sphericity after HRS. The aim of this study was to quantitatively assess improvement in hip sphericity after HRS in patients with CP. We retrospectively analyzed hip radiographs of patients who had undergone HRS because of CP-associated hip displacement. The pre- and postoperative migration percentage (MP), femoral neck-shaft angle (NSA), and sphericity, as determined by the Mose hip ratio (MHR), age at surgery, Gross Motor Function Classification System level, surgical history including Dega pelvic osteotomy, and triradiate cartilage status were studied. Regression analyses using linear mixed model were performed to identify factors affecting hip sphericity improvement.Aims
Methods
The purpose of this study was to examine whether leg-length discrepancy (LLD) following unilateral total hip arthroplasty (THA) affects the incidence of contralateral head collapse and subsequent THA in patients with bilateral osteonecrosis, and to determine factors associated with subsequent collapse. We identified 121 patients with bilateral non-traumatic osteonecrosis who underwent THA between 2003 and 2011 to treat a symptomatic hip, and who also exhibited medium-to-large lesions (necrotic area ≥ 30%) in an otherwise asymptomatic non-operated hip. Of the 121 patients, 71 were male (59%) and 50 were female (41%), with a mean age of 51 years (19 to 71) at the time of initial THA. All patients were followed for at least five years and were assessed according to the presence of a LLD (non-LLD Aims
Patients and Methods
Preservation of both anterior and posterior cruciate ligaments in total knee arthroplasty (TKA) can lead to near-normal post-operative joint mechanics and improved knee function. We hypothesised that a patient-specific bicruciate-retaining prosthesis preserves near-normal kinematics better than standard off-the-shelf posterior cruciate-retaining and bicruciate-retaining prostheses in TKA. We developed the validated models to evaluate the post-operative kinematics in patient-specific bicruciate-retaining, standard off-the-shelf bicruciate-retaining and posterior cruciate-retaining TKA under gait and deep knee bend loading conditions using numerical simulation.Objectives
Methods
Recently, the combination of press-fit acetabular cup with ceramic articulation is a widely used for implanting cementless acetabular components and has been shown to provide good initial stability. However, these methods may lead to elevating stresses, changing in the bearing geometries, and increasing wear due to deformation of the cup and insert. In addition, there is a potential for failure of ceramic inserts when a large ball head was used because it should be assembled with shallow thickness of the acetabular cup. For risk reduction of it, we applied direct metal tooling (DMT) based on 3D printing for porous coating on the cup. Due to its capability of mechanical strength, DMT coated cup could be feasible to provide better stability than conventional coating. Therefore, we constructed laboratory models for deformation test simulating an press-fit situation with large ceramic ball head to evaluate stability of the DMT coated cup compared with conventional coated cup. The deformation test was performed according to the test setup described by Z. M. Jin et al. The under reaming of the cavity in a two-point pinching cavity models of polyurethane (PU) foam block (SAWBONES, Pacific Research Laboratories, USA) with a grade 30 were constructed. Titanium plasma spray (TPS) and direct metal tooling (DMT) coated acetabular cups (BENCOX Mirabo and Z Mirabo Cup, Corentec Co. Ltd., KOREA) with a 52 mm size (n=3, respectively) were used for the test. These cups were implanted into the PU foam blocks, and followed by impaction of the inserts (BIOLOX delta, Ceramtec, GE) with a 36/44 size (n=6) into the acetabupar cups as shown in Fig. 1. Roundness and inner diameter of the acetabular cups and inserts were measured using a coordinate measuring machine (BHN 305, Mitutoyo Neuss, GE) in three levels; E2, E3, and E4 (3, 5, and 7 mm below the front face, respectively). Also, these parameters of the acetabular cup were measured in two level; E1 and E5 (5 and 11 mm below the front face) as shown in Fig. 2. Changes in roundness and inner diameter of the cup and insert were measured to evaluate deformation in relation to porous coating on the acetabular cups.Introduction
Materials and Methods
Although thigh pain is an annoying problem after total hip arthroplasty (THA), little information has been known about its natural course. To determine the frequency, time of onset, and duration of thigh pain after cementless THA, we evaluated 240 patients (240 hips) who underwent primary THA because of femoral head osteonecrosis with the use of a single tapered stem.Background
Methods
The acetabular cup should be properly oriented to prevent dislocation and to reduce wear and leg length discrepancy. Despite advances in surgical techniques and instrumentation, achieving proper cup placement in total hip arthroplasty (THA) is challenging with potentially large variations of cup position and limited accuracy. We evaluated whether cup placement on anatomical location ensured original center of rotation (COR) and surgeon's experiences of THA reduced variations in acetabular component positioning. We retrospectively reviewed 145 patients (145 hips) of unilateral THAs with normal contralateral structures of acetabulum and femoral head. All surgeries were performed using the modified posterolateral approach that preserves short external rotator muscles. All of the 145 THAs were performed by two surgeons, who were in the same teaching hospital, but had differences in surgical experience and expertise for THA. The patients were divided into two groups based upon surgical experience: (1) the highly experienced surgeon's group: who had previously performed over 1000 THAs (YSK, 101 hips), and (2) the less experienced novice's group: who had performed fewer than 30 THAs (YWL, 44 hips). Real vertical distances, from the COR to the inter-tear drop line, and the real horizontal distances, from the COR to the lateral wall of the tear drop, were measured preoperatively using picture archiving communication system (PACS) based precise method. Postoperative ones were measured and equalized by use of a magnification marker placed on preoperative plain radiographs. And cup inclination was measured directly on the AP radiographs and anteversion was calculated by trigonometric functions. The patient's mean age was 52.1 years (range, 20–86).Introduction
Methods
Cementless arthroplasty has been widely used for younger patients with osteoarthritis and other joint pathology. Cementless arthroplasty will be required to porous surface which is to similar to the trabecular bone for bone ingrowth. Titanium Plasma Spray (TPS) has been worldwide used for the porous coating method on arthroplasty. However, TPS coating is limited that would not to establish optimal porosity for bone ingrowth due to arbitary position of melted powder by plasma gas on substrate. Therefore, it is reported coating detached from its substrate (i.e. arthroplasty) is induced implant loosening. Thus, a novel Laser-aided Direct Metal Tooling (DMT) based on Additive Manufacturing (AM) was developed to overcome these limitations. In this study, we were done to assess stereological analysis, static tensile, shear, abrasion test, and physical analysis for evaluation of the efficacy of DMT which was newly-developed coating technology. Then, mechanical characteristics of DMT coating were compared to commercial TPS coating's. First, porosity of the DMT coating was evaluated using Microphotography and Scanning Electron Microscopy (SEM), as described in Figure 1. Static tensile and shear test for assessment of mechanical characteristic in relation to the DMT and TPS coating specimens were conducted on the basis of ASTM F1147 and F1044 using universal testing machine (Endolab®, Servohydraulic Test Frame, DE). Maximum tensile strength and maximum shear strength were evaluated for each specimen (n=5). Abrasion test was performed based on ASTM F1978 using Taber® Rotary Platform Abraser Model 5135 (TABER®Industries, USA). Abrasion losses for each specimen (n=6) were measured at 2, 5, 10, and 100 cycles, respectively.Introduction
Materials and Methods
3-D Printing with direct metal tooling (DMT) technology was innovatively introduced in the field of surface treatment of prosthesis to improve, moreover to overcome the problems of plasma spray, hopefully resulting in opening the possibility of another page of coating technology. We presumed such modification on the surface of Co-Cr alloy by DMT would improve the ability of Co-Cr alloys to osseointegrate. We compared the in vitro and in vivo ability of cells to adhere to DMT coated Co-Cr alloy to that of two different types of surface modifications: machined and plasma spray(TPS). We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines of human were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and avb3 integrin. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the MAO group increased in comparison to those in the machined and grit-blasted groups.Introduction
Method
The plasma spray(TPS) has come to be accepted as one of the more reliable methods of porous coating of prosthesis, it is not without some technical limitations, especially with regard to precise modulation of pore size, porosity, and roughness. However, the plasma spray(TPS) not often but seriously faces problems such as bead detachment related poor osteointegration, weakness of metal strength and high manufacturing costs in addition to its various technical limitations. Currently, there has been much research into developing a more economical and effective method for porous coating of the prosthesis. In light of such demand, 3D Printing with DMT Technology has been introduced into the field of surface treatment of prosthesis with promising expectations. DMT technology -an additive fabrication process that uses high-power laser and various metal powders in order to produce fully dense and geometrically complex metal components, molds, and dies directly from digital CAD model data of 3D subjects aims to help overcome many of the problems associated with plasma spray and thereby open a new chapter of endless possibilities for coating technology. In this study, the porous coating specimen using 3-D DMT metal printing was characterized morphologically as well as biomechanically, in terms of 1) pore size 2) porosity 3) tensile strength 4) shear strength 5) roughness respectively. The biological cyto-compatibility was evaluated by culturing human osteoblast-like cells(Saos-2: ATCC HTB85) on the surface of round discs with porous coating to demonstrate the biological influence on the porosity of the specimens with different surface treatment for comparative analysis. The evaluation was accompanied by assessment of cell proliferation and morphology with arrangement of actin filament and expression of adhesion molecule with αvβ3 integrin. While 3-D DMT coating specimen showed relatively regular porosity in the range of 150–500µm with the increase of porosity about 83%, the mechanical behavior remarkably improved, compared to TPS: shear strength 13%, fatigue failure 30%, roughness 16%, respectively. Also worth noting, the tensile strength was unable to be measured because the glue for test had fallen off. (Fig. 1) There is no transitional zone underneath the porous coating layer.(Fig. 2) From the aspect of biocompatibility, 3-D coating showed better cell attachment, spreading of cytoskeleton, cell proliferation, and expression of osteogenic markers than TPS, even if not significantly.(Fig. 3) Additionally, cell migration assay was performed with double chamber study, and gene expression was evaluated by measuring alkaline phosphatase(ALP) levels and analyzing mRNA expression for ostepontin(OPG) and osteocalcin(OC). In conclusion, the study reinforces the popular stance that the implementation of 3-D DMT could open up new possibilities for coating technology and form a new chapter in the history of prosthesis development.
CXC chemokine receptor 4 (CXCR4) is a specific receptor for stromal-derived-factor 1 (SDF-1). SDF-1/CXCR4 interaction contributes to the regulation of endotherial progenitor cell (EPC) recruitment in ischemic tissues. The purpose of this study is to investigate the mechanistic function of CXCR4 on EPCs for bone fracture healing. We made CXCR4 gene knockout mice using the Cre/loxP system. A reproducible model of femoral fracture was created in both Tie2-Cre CXCR4 knockout mice (CXCR4KO) and wild type mice (control). To evaluate gain function of the SDF-1/CXCR4 pathway, we set three groups of the SDF-1 intraperitoneally injected group, wild type group, and SDF-1 injected CXCR4 KO group.Introduction
Materials and methods
We compared extrusion of the allograft after
medial and lateral meniscal allograft transplantation and examined
the correlation between the extent of extrusion and the clinical
outcome. A total of 73 lateral and 26 medial meniscus allografts
were evaluated by MRI at a mean of 32 months (24 to 59) in 99 patients
(67 men, 32 women) with a mean age of 35 years (21 to 52). The absolute
values and the proportional widths of extruded menisci as a percentage were
measured in coronal images that showed maximum extrusion. Functional
assessments were performed using Lysholm scores. The mean extrusion
was 4.7 mm (1.8 to 7.7) for lateral menisci and 2.9 mm (1.2 to 6.5)
for medial menisci (p <
0.001), and the mean percentage extrusions
were 52.0% (23.8% to 81.8%) and 31.2% (11.6% to 63.4%), respectively
(p <
0.001). Mean Lysholm scores increased significantly from
49.0 (10 to 83) pre-operatively to 86.6 (33 to 99) at final follow-up
for lateral menisci (p = 0.001) and from 50.9 (15 to 88) to 88.3
(32 to 100) for medial menisci (p <
0.001). The final mean Lysholm
scores were similar in the two groups (p = 0.312). Furthermore,
Lysholm scores were not found to be correlated with degree of extrusion
(p = 0.242). Thus, transplanted lateral menisci extrude more significantly
than transplanted medial menisci. However, the clinical outcome
after meniscal transplantation was not found to be adversely affected
by extrusion of the allograft.
The osseointegration of implants is related to the early interactions between osteoblastic cells and titanium surfaces. The behavior of osteoblast cells was compared on four different titanium surfaces in vitro and in vivo: machined, blasted, plasma spray and micro-arc oxidation. X-ray diffraction and scanning electron microscope investigations were performed in order to assess the structure and morphology. Biologic and morphologic responses to the osteoblast cell lines (Saos-2) were then examined, using Promega proliferation assay, alkaline phosphatase activity, vβ3 integrin expression and cytoskeleton staining (Rhodamine-Phallodine). The analysis of gene expression for osteocalcin and collagen I was done through RT-PCR. In addition, differential histologic evaluation and interfacial strength at the bone-implant interfaces were then evaluated in the distal femur of four beagle dogs. In conclusion, micro-arc oxidation of titanium appears to exhibit more favorable osteoblast adhesion and stronger interfacial strength than the compared groups in vitro and in vivo as well.
The use of polymethylmethacrylate (PMMA) in orthopaedic reconstructive surgery can increase the possibility of cardiovascular dysfunction remains a debate. This study was undertaken to determine if cemented hemiarthroplasty is safe in treatment of femoral neck fracture in patients with ischemic heart disease. Between March 1999 and February 2004, we performed cemented hemiarthroplasties for displaced femoral neck fractures on 158 consecutive patients. This retrospective study consisted of 44 patients with ischemic heart disease(group 1) and 58 patients of age matched control(group 2). We compared the mortality rate, the incidence of deep vein thrombosis (DVT), pulmonary embolism, cerebrovascular disease, dislocation, deep infection, the amount of postoperative blood loss, and the grade of cementation by Barrack in radiograph between two groups. No difference was found in perioperative mortality rate, deep infection rate, the incidence of DVT or pulmonary embolism, the newly developed heart ischemic event or brain hemorrhagic lesion between the two groups. But there were more incidence of dislocation related to weakness by past brain ischemic lesion and the newly developed brain ischemia in patients of group 1 than group 2(p <
0.05). More importantly, six patients in group 1 had transient symptoms of dyspnea, signs of hypotension, and bradycardia during two days postoperatively, which is suspicious of embolic phenomenon, even though it was not confirmed. More closer and careful observations for the occurrence of dislocation related to previous brain ischemia, or newly developed brain ischemic lesion or embolic phenomenon and appropriate thromboprophylaxis are necessary in patients with ischemic heart disease after a cemented hemiarthroplasty for the treatment of femoral neck fracture.
In a previous study, we found that pre-TKA patients were severely disabled in high-flexion activities but perceived these disabilities as being no more important than pain relief and the restoration of daily routine activities. This study was conducted to investigate functional disabilities and patient satisfaction in Korean patients after TKA. Of 387 patients who had undergone TKA with a follow-up longer than 12 months, 270 (69.7%) completed a questionnaire designed to evaluate functional disabilities, perceived importance and patient satisfaction. The top 5 severe functional disabilities were difficulties in kneeling, squatting, sitting with legs crossed, sexual activity, and recreational activities. The top 5 in order of perceived importance were difficulties in walking, using a bathtub, working, climbing stairs, and recreation activities. Severities of functional disabilities were not found to be correlated with perceived importance. The patients (8.5%) dissatisfied with their replaced knees had more severe functional disabilities than the satisfied for most activities. The dissatisfied patients tended to perceive functional disabilities in high-flexion activities to be more important than the satisfied. This study indicates that despite severe disabilities in high-flexion activities, most Korean patients after TKA would not consider high-flexion disability to be more important than other daily routine activities. Moreover, postoperative high-flexion disabilities would not adversely influence satisfaction for most patients. Nevertheless, such disabilities are likely to cause dissatisfaction among those that are not prepared to modify their traditional life-styles.
Biocompatibility of Co-Cr alloy was significantly improved by forming rough TiO2 layer on the surface. The TiO2 layer was formed by coating the Co-Cr alloy with Ti through electron beam deposition followed by micro-arc oxidation (MAO) of the Ti. Biocompatibility of Co-Cr alloy was enhanced by coating with titanium, and it was improved further by micro-arc oxidation treatment. MAO process was dependent on the thickness of coated titanium layer and applied voltage. There were close relationships between the phase, morphology and thickness of TiO2 layer and the applied voltage. Biocompatibility of the specimens coated with Ti and MAO treated after Ti coating were evaluated by in vitro ALP activity tests.
Modified posterior approach preserving short external rotators would be able to contribute greatly to prevent dislocation after total hip arthroplasty. We modified the posterior approach to the hip by preserving the external rotator muscles in order to enhance joint stability after total hip arthroplasty in patients with osteonecrosis of the femoral head. The aim of the this study was to determine the influence of external rotator preserving posterior approach in primary total hip replacement on early dislocation and clinical outcome. Three hundred sixty-four primary total hip replacements were divided into two groups based on how the external rotators were treated at surgery. External rotator preservation (Group 1, 165 hips) group was compared with reattachment (Group 2, 199 hips) group by evaluating the clinical and radiographic outcome at one year postoperative. Anteversion was significantly less in Group 1 as compared to Group 2 (P <
0.001). There was no significant difference in inclination between the groups (P >
0.05 in all comparisons). No dislocations were found in 165 hips with external rotator preservation whereas dislocations was noted in 11 (3.9%) in Groups 2, respectively. Group 1 had the higher mean Harris hip score (97.2±2.9 points) as compared with Group 2(94.9±3.4). The results of this study showed that external rotators could play an important role in preserving joint stability after total hip arthroplasty in patients with osteonecrosis of the femoral head. It can be implied that this modified posterior approach would be able to contribute greatly to prevention of dislocation, and improve clinical outcome after total hip arthroplasty.
We developed a modified posterior approach that preserved the short external rotator muscles to prevent dislocation after THA or BHA. The present study aimed to evaluate the effectiveness of short external rotator preserving posterior(ERP) approach for bipolar hemiarthroplasty in treatment of femoral neck fractures in patients with neurologic disorders. Between March 2004 and February 2006, we performed 187 cementless bipolar hemiarthroplasties for displaced femoral neck fractures on 36 patients with neurologic disorders, who were operated on by ERP approach (Group 1) and 151 patients without neurologic deficits, who were operated on by conventional posterolateral approach (Group 2). We compared operation time, the amount of postoperative blood loss, the early postoperative complication rates, the dislocation rate within 1 year, and duration of hospital stay between two groups. The amount of postoperative blood loss was significantly decreased in group 1(p <
0.01). There were no significant differences in mean operation time and early postoperative complication rate including wound problem, deep vein thrombosis or infection and duration of hospital stay. There was no dislocation after operation in group 1, but seven patient (4.6%) had dislocation in group 2. Nine patients (25.0%) died within postoperative 1 year in group 1 and twenty six patients (17.2%) died in group 2. Cementless bipolar hemiarthroplasty through ERP approach provides a favorable outcome for treatment of displaced femoral neck fracture in patients with neurologic disorders who is considered as high risk of dislocation. Also, it decreases the postoperative blood loss and the needs of postoperative abduction brace.
