INTRODUCTION. Understanding
Introduction. The first carpometacarpal (CMC) joint is the second most common joint of the hand affected by degenerative osteoarthritis (OA). 1. Laxity of ligamentous stabilizers that attach the first metacarpal bone (MC1) and the trapezium bone (TZ), notably the volar anterior oblique ligament (AOL), has been associated with cartilage wear, joint space narrowing, osteophyte formation, and dorsal-radial CMC subluxation. 2. In addition, the proximal-volar end of the MC1 has a bony prominence known as the palmar lip (PL) that adds conformity to this double-saddle joint, and is thought to be a supplemental dorsal stabilizer. Currently, no study has looked at the changes to the 3D shape and relative positions of these structures with OA. Methods. CT scans of patients with clinically diagnosed CMC OA (n=11, mean age 73 [60–97], 8 females) and CT scans of ‘normal’ patients with no documented history of CMC OA (n=11, mean age 37 [20–51], 6 females) were obtained with the hand in a prone position. 3D reconstructions of the MC1 and TZ bones were created, and each assigned a coordinate system. 3. The long axis of the MC1 and the proximal-distal axis of the TZ were established, and the location where they intersected the CMC articular surface was defined as their articular center points, X and O, respectively (Figure 1). Using the TZ as a fixed reference, we calculated the relative position of X in the dorsal-ventral and radial-ulnar directions. A two sample t-test was performed to compare the normal and OA groups. In addition, the distal position of the PL relative to X was recorded. Results. The dorsal position of the MC1 relative to the TZ was significantly greater (p=0.002) in the OA group compared with the normal group, with mean dorsal positions of 7.1 and 3.2mm, respectively (Figure 2). The distal position of the PL relative to X was also significantly greater (p=0.001) in the OA group when compared with the normal group, with mean positions of 5.8 and 1.9mm, respectively (Figure 3). Discussion. Dorsal migration of the MC1 in the OA group would suggest a compromised AOL, known to be elongated or absent intraoperatively. Without a sufficient AOL, the PL was positioned more distally in the OA group, as the load on the PL during extension activities could possibly exceed cartilage strength resulting in subchondral bone remodeling and further joint degeneration. We did not observe radial migration of the MC1 bone possibly due to the presence of bony osteophytes that can reduce abduction-adduction function in OA patients. 4. The relationship discovered between OA and changes to
Knee laxity following anterior cruciate ligament (ACL) injury is a complex phenomenon influenced by various biomechanical and anatomical factors. The contribution of soft tissue injuries – such as ligaments, menisci, and capsule – has been previously defined, but less is known about the effects of bony morphology. (Tanaka et al, KSSTA 2012) The pivot shift test is frequently employed in the clinical setting to assess the combined rotational and translational laxity of the ACL deficient knee. In order to standardise the maneuver and allow for reproducible interpretation, the quantitative pivot shift test was developed. (Hoshino et al, KSSTA 2013) The aim of this study is to employ the quantitative pivot shift test to determine the effects of
Introduction. The ability to create patient-specific implants (PSI) at the point-of-care has become a desire for clinicians wanting to provide affordable and customized treatment. While some hospitals have already adopted extrusion-based 3D printing (fused filament fabrication; FFF) for creating non-implantable instruments, recent innovations have allowed for the printing of high-temperature implantable polymers including polyetheretherketone (PEEK). With interest in FFF PEEK implants growing, it is important to identify methods for printing favorable implant characteristics such as porosity for osseointegration. In this study, we assess the effect of porous geometry on the cell response and mechanical properties for FFF-printed porous PEEK. We also demonstrate the ability to design and print customized porous implants, specifically for a sheep tibial segmental defect model, based on CT images and using the geometry of triply periodic minimal surfaces (TPMS). Methods. Three porous constructs – a rectilinear pattern and gyroid/diamond TPMSs – were designed to mimic trabecular
Evaluate precisely and reproducibly tridimensional positioning of bone tunnels in anterior cruciate ligament reconstructions (ACL). To propose biplanar stereoradiographic imaging as a new reference in tridimensional evaluation of ACL reconstruction (ACLR). Comparing knee 3D models issued from EOStm low-irradiation biplanar X-Ray with those issued from computed tomography (CT-Scan) high definition images will allow a
INTRODUCTION. It is generally accepted that strong hammering is necessary for the press fit fixation of a joint prosthesis. In this regard, large stress must remain within bone tissues for a long period. This residual stress is, however, some different from the feasible mechanical stimuli for bone tissues because that is stationary, continuous and directed from within outward unlike physiological conditions. The response on this residual stress, which may induce the disorder of the fixation of implant, has not been discussed, yet. In the present study, we designed an experimental method to exert a stationary load from inside of a femur of a rat by inserting a loop spring made from a super elastic wire of titanium alloy. Response of the femur was assessed by
Introduction:. Although cementless total hip arthroplasty (THA) is well accepted, the optimal femoral component design remains unknown. Among early complications, loosening and periprosthetic fracture persist and are related to implant design. The purpose of this study is to compare the anatomic fit and early subsidence of two different stem designs: a modern, short taper-wedge design and a traditional fit-and-fill design. Methods:. A retrospective cohort study of 129 consecutive cementless THAs using two different femoral stems was performed. A modern taper-wedge stem was used in 65 hips and a traditional proximal fit-and-fill stem was used in 64 hips. Radiographic analysis was performed at preoperative, immediate postoperative and 1-month postoperative intervals. The radiographic parameters of
Pre-existing hip pathology such as femoroacetabular impingement is believed by some, to have a direct causal relationship with osteoarthritis of the hip. The strength of this relationship remains unknown. We investigate the prevalence of abnormal
Introduction. Trabecular Titanium is a biomaterial characterized by a regular three-dimensional hexagonal cell structure imitating trabecular
Introduction:. Subchondral bone density (SBD) distribution is an important parameter regarding that may be important when considering implant stability. This parameter is a reflection of the loading experienced by the joint throughout the lifetime and may be useful in pre-surgical planning and implant design. Clinically, the question of the glenoid surface preparation for TSA/RSA remains controversial, despite numerous published studies on glenoid
Periprosthetic fractures around the femur during and after total hip arthroplasty (THA) remain a common mode of failure. It is important therefore to recognise those factors that place patients at increased risk for development of this complication. Prevention of this complication, always trumps treatment. Risk factors can be stratified into: 1. Patient related factors; 2. Host bone and anatomical considerations; 3. Procedural related factors; and 4. Implant related factors. Patient Factors. There are several patient related factors that place patients at risk for development of a periprosthetic fracture during and after total hip arthroplasty. Metabolic bone disease, particularly osteoporosis increases the risk of periprosthetic fracture. In addition, patients that smoke, have long term steroid use or disuse, osteopenia due to inactivity should be identified. A metabolic bone work up and evaluation of bone mineralization with a bone densitometry test can be helpful in identifying and implementing treatment prior to THA. Pre-operative Host Bone and Anatomic Considerations. In addition to metabolic bone disease the “shape of the bone” should be taken into consideration as well. Dorr has described three different types of
Introduction. Range of motion (ROM) simulation of the hip is useful to understand the maximum impingement free ROM in total hip arthroplasty (THA). In spite of a complex multi-directional movement of the hip in daily life, most of the previous reports have evaluated the ROM only in specific directions such as flexion-extension, abduction-adduction, and internal - external rotation at 0° or 90° of hip flexion. Therefore, we developed ROM simulation software (THA analyzer) to measure impingement free ROM in any positions of the hip. Recent designs of the hip implants give a wider ROM by increasing the head diameter and then, bone to bone impingement can be a ROM limit factor particularly in a combination of deep flexion, adduction and internal rotation of the hip. Therefore, the purpose of this study were to observe an individual variation in the pattern of the bone impingement ROM in normal hip bone models using this software, to classify the bone impingement ROM mapping types and to clarify the factors affecting the bone impingement type. Methods. The subjects were 15 normal hips of 15 patients. Three dimensional surface models of the pelvis and femur were reconstructed from Computer tomography (CT) images. We performed virtual hip implantation with the same center of rotation, femoral offset, and leg length as the original hips. Subsequently, we created the ROM mapping until bone impingement using THA analyzer. We measured the following factors influenced on the bone impingement map patterns; the neck shaft angle, the femoral offset, femoral anteversion, pelvic tilt, acetabular anteversion, sharp angle, and CE angle. These factors were compared between the two groups. Statistical analysis was performed with Mann-Whitney U test, and statistical significance was set at P<0.05. Results. According to the borderline of ROM at the flexion-internal rotation corner on the bone impingement map, the hips were classified into two groups; group-A showed more than 45° of the borderline slope at the flexion-internal rotation corner and the remaining hips were group-B. (Fig.1). There were 7 hips in group-A and 8 hips in group-B. Femoral offset was 36.8±2.2 mm in group-A and 30±2.7 mm in group-B. Femoral anteversion was 32±6.4° in-group A and 43 ±4.8° in group-B. There were statistically significant differences in the femoral offset and femoral anteversion between the groups. There were no significant differences in the other factors. Discussion. The results of this study showed various ROM map patterns even in normal hips and we classified them into two groups. An increased femoral offset or a decreased femoral anteversion revealed an early impinge in internal rotation. ROM until bone impingement is affected by the individual
Osteoarthritic (OA) changes to the
Background. Constitutional knee varus increases the risk of medial OA disease due to increase in the knee adduction moment and shifting of the mechanical axis medially. Hueter-Volkmann's law states that the amount of load experienced by the growth plate during development influences the
Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long
Introduction. Migration of the trial femoral head is a rarely occurring complication of total hip arthroplasty (THA) performed using the anterolateral approach (ALA). This migration of the trial femoral head under the rectus femoris is extremely risky because of the anatomical situation. Analyzing the morphological character of a case of migration may help us to avoid this risk. Objective. We analyzed the three-dimensional
Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long
Deformity can be associated with significant bone loss, ligament laxity, soft-tissue contractures, distortion of long
Combined anteversion angle of acetabular component and femeral neck is an important factor for total hip arthroplasty (THA) as it may affect impingement and dislocation. Previous studies have collected data mainly from direct measurements of
INTRODUCTION. Immediate post-operative stability of a cementless hip design is one of the key factors for osseointegration and therefore long-term success [1]. This study compared the initial stability of a novel, shortened, hip stem to a predicate standard tapered wedge stem design with good, long-term, clinical history. The novel stem is a shortened, flat tapered wedge stem design with a shape that was based on a