CORRELATION BETWEEN MORPHOMETRY OF PATELLAR LIGAMENT AND PATELLA-AN AID TO TOTAL KNEE ARTHROPLASTY

Background: Patellar ligament is of surgical importance in procedures pertaining to total knee arthroplasty. It is extensively used as an autogenous graft for endoscopic anterior cruciate ligament reconstruction. Patellar ligament is the most preferred autograft owing to sufcient load to failure strength and stiffness. Purpose of the study: Dimensions of patella have been shown to be of anthropometric importance and is also used for personal identication as the bone is resistant to postmortem changes. There is paucity of literature on studies correlating the dimensions of patellar ligament and patella bone in Indian population. This study is the rst of its kind to provide data on the same. 53 prosected lower limbs were used to study the morphome Material and Methods: try of Patellar ligament and Patella using digital vernier calipers. The mean length, width and thickness values of Patellar ligament and bone were recorded. Pearson correlation coefcient was used to test the strength of association between the two variables. It was seen that there was negative correlation between Results: patella length and ligament length and thickness. There was positive correlation between patella length and ligament width. Patella width correlated positively with ligament length and ligament width but negatively with ligament thickness. Patella thickness correlated negatively with ligament length and thickness but positively with ligament width. This Conclusion- study will provide valuable anthropometric data and aid the orthopaedic surgeons performing knee surgeries.

Examination of the proximodistal patellar position in small dogs in relation to anatomical features of the distal femur and medial patellar luxation

Objective To determine the influence of anatomical features of the distal femur on the proximodistal patellar position and compare the proximodistal patellar position between dogs with and without medial patellar luxation (MPL). Study design Retrospective case series (n = 71). Methods Mediolateral-view radiographs of clinical cases of dogs weighing less than 15 kg were obtained. The stifle joint angle, patellar ligament length, patellar length, size of the femoral condyle, trochlear length, and trochlear angle were measured and included in multiple linear regression analyses to ascertain their effects on the proximodistal patellar position. Radiographs were divided into MPL and control groups. The effects of MPL on the proximodistal patellar position and morphological factors were also examined. Results The final model for the proximodistal patellar position revealed that the patella became distal as the ratio of the patellar ligament length to patellar length decreased, the trochlear angle relative to the femur increased, the trochlear length relative to the patellar length increased, or the trochlear length relative to the femoral condyle width decreased. The proximodistal patellar position in the MPL group was not significantly different from that in the control group despite the trend towards a distally positioned patella (p = 0.073). The MPL group showed a significantly shorter trochlea (p<0.001) and greater trochlear angle relative to the femur (p = 0.029) than the control group. Conclusion The proximodistal patellar position depends on multiple factors, and its determination based on PLL/PL alone may not be appropriate. Dogs with MPL did not have a proximally positioned patella compared with dogs without MPL. Although hindlimbs with MPL had a shorter trochlea than those without patellar luxation, this difference did not appear to be sufficient to displace the patellar position proximally in small dogs, possibly compensated by increased trochlear angle relative to the femur.

A Novel Kinematic Model of the Tibiofemoral Joint Based On a Parallel Mechanism

This paper presents a complete kinematic model of the tibiofemoral joint based on a RRPP + 4-SPS parallel mechanism, where R, P and S stands for revolute, prismatic and spherical joints respectively. The model accounts for the contact between tibia and femur, and the four major ligaments: Anterior Cruciate, Posterior Cruciate, Medial Collateral and Lateral Collateral, with anatomical significance in their length variations. An experimental flexion passive motion task is performed, and the kinematic model is tested to determine its capability to reproduce the workspace of the motion task. In addition, an optimization process is performed to simulate prescribed ligament length variations during the motion task. The proposed kinematic model is capable to reproduce with high accuracy an experimental three-dimensional workspace, and at the same time, to simulate prescribed ligament length variation during the spatial flexion task. Prescribed ligament length variations are achieved through an optimization process of the ligament insertion points. This model can be used to improve the multibody kinematic optimization process during gait analysis, and also in the design of rehabilitation devices as well as trajectories to accelerate the recovery of injured ligaments. The model shows potential to predict ligament length variations during different motion tasks, and can serve as a basis to develop complex models for kinetostatic and dynamic analyses without dealing with computationally expensive models.

Fracture Propagation Pathways Pattern on UV-Irradiated Double-Edge Cracked of Mordenite Zeolite-HDPE Composites

Mechanical failure of zeolite-high density polyethylene (HDPE) material applied to skull bone implants is a material fracture that cannot be controlled. An important step to minimize failure due to fracture is to understand the fracture characteristics indicated by the propagation path pattern. This study aimed to investigate the fracture propagation pathways of zeolite-HDPE composites in quasi-static conditions. UV-irradiated Double-edge cracked zeolite-HDPE composite was tested in mode I (a stress perpendicular to the plane of the crack) in a universal testing machine (UTM) with a crosshead speed of 2 mm/min at a constant room temperature of approximately 25°C. The stress and elongation were registered by the UTM. During loading, the evolution of cracks in the ligament length region was recorded with the camera so that the crack propagation pathway until the total fracture occurs can be clearly observed. The results show that the crack propagation pathway patterns were not all straight and parallel to the ligament length. They are also found in a deviant state of the ligament length line by forming an angle α. created between the ligament length line and the fracture propagation deviation direction. This deviation occurs after the crack propagates straight away from the initial-cracks.

Diagnostic Value of Modern Methods of Ocular Anterior Segment Visualization in Intumescent Cataract

Purpose: tо evaluate the diagnostic capabilities of optical coherence tomography (OCT), Scheimpflug camera and ultrasound biomicroscopy (UBM) in examining topography of the ocular anterior segment and lens in mature intumescent cataract. Patients and methods. 23 eyes with mature intumescent cataract were examined using OCT (RTVue-100, Optovue, USA), Scheimpflug camera (Pentacam HR, Oculus, Germany) and UBM (UD 8000, Tomey, Japan). We examined the anterior chamber depth, profile and magnitude of the anterior chamber angle, distance “trabecula-iris at 500 microns”, thickness of the liquid lenticular mass layer, lens thickness, Zinn ligament length within four segments, equatorial angle. Results. We managed to measure the anterior chamber depth using UBM and Scheimpflug camera. UBM measurement was 1.96 ± 0.14 mm, Scheimpflug camera — 1.91 ± 0.11 mm. We revealed narrowing of the anterior chamber angle up to 11.54 ± 2.19° in UMB examination, to 11.49 ± 2.17° in OCT measuring and to 11.63 ± 2.21° in examining by Scheimpflug camera. Distance “trabecula-iris 500” was 0.212 ± 0.037 mm in UMB examination, 0.218 ± 0.042 mm — by means of OCT, Scheimpflug camera measurement was unsuccessful. The rest parameters were examined only by UBM. The lens thickness was 5.26 ± 0.13 mm. The anterior layer of liquid lenticular mass was 0.85 ± 0.06 mm. Zinn ligament length in the outer segment was 0.708 ± 0.072 mm, in the internal segment — 0.731 ± 0.089 mm, in the superior segment — 0.704 ± 0.084 mm, in the inferior segment — 0.876 ± 0.089 mm. The equatorial angle in two opposite segments was 32.52 ± 0.92°. Conclusion. Ultrasound biomicroscopy has the biggest value in examining topography of the ocular anterior segment and lens in mature intumescent cataract, since only this method allows achieving the whole complex of data necessary to evaluate the swelling lens parameters. This can serve as a basis for developing the appropriate tactics of surgical intervention.