Aims. Postoperative
Objectives. Elevated proximal tibial bone strain may cause unexplained pain, an important cause of unicompartmental knee arthroplasty (UKA) revision. This study investigates the effect of tibial component alignment in metal-backed (MB) and all-polyethylene (AP) fixed-bearing medial UKAs on bone strain, using an experimentally validated finite element model (FEM). Methods. A previously experimentally validated FEM of a composite tibia implanted with a cemented fixed-bearing UKA (MB and AP) was used. Standard alignment (medial proximal tibial angle 90°, 6° posterior slope), coronal
Objectives.
An increasingly used treatment for end-stage ankle osteoarthritis is total ankle replacement (TAR). However, implant loosening and subsidence are commonly reported complications, leading to relatively high TAR failure rates.
Introduction and Objective. Malunion after trauma can lead to coronal plane
Patellofemoral complications are among the important reasons for revision knee arthroplasty. Femoral component malposition has been implicated in patellofemoral maltracking, which is associated with anterior knee pain, subluxation, fracture, wear, and aseptic loosening. Rotating-platform mobile bearings compensate for malrotation between the tibial and femoral components. It has been suggested that rotating bearings may also reduce the patellofemoral maltracking resulting from femoral component malposition. We constructed a dynamic musculoskeletal model of weight-bearing knee flexion in a knee implanted with posterior cruciate-retaining arthroplasty components (LifeMOD/KneeSIM, LifeModeler Inc). The model was validated using tibiofemoral and patellofemoral kinematics and forces measured in cadaver knees on an Oxford knee rig. Knee kinematics and patellofemoral forces were measured after simulating axial malrotation of the femoral component (±3° of the transepicondylar reference line). Differences in patellofemoral kinematics and forces between the fixed- and rotating-bearing conditions were analysed. Rotational
Introduction. Total ankle replacement (TAR) is surgically complex;
Abstract. OBJECTIVE. Knee varus
Background. Total Knee Replacement (TKR) is an effective treatment for knee arthritis. One long held principle of TKRs is positioning the components in alignment with the mechanical axis to restore the overall limb alignment to 180 ± 3 degrees. However, this view has been challenged recently. Given the high number of replacements performed, clarity on this integral aspect is necessary. Our objective was to investigate the association between
In recent years, the use of computed tomography (CT) has made it possible to obtain without distortion images of axial sections of the patella with the knee in the first 15°–20° of flexion. We performed CT examinations on 27 patients aged between 11 and 17 years. We considered patients who had anterior knee pain with or without a feeling of patellar instability. CT examinations were performed with the knee flexed to 15° with and without quadriceps contraction. The tomograms obtained were analysed considering: (1) the congruence angle (CA), (2) the patellar tilt angle (PTA), (3) the sulcus angle (SA) and (4) trochlear depth (TD). We performed CT examinations on a control group of 20 patients aged between 11 to 17 years. Statistical analysis was performed by using the analysis of variation (ANOVA) test or the Student’s t-test on paired or unpaired data. The difference between control knees and symptomatic knees was significant for all of the CT variables (unpaired t-test).
Abstract. Objectives. Stem
Recently, it has been reported that the posterior stabilised implant clinically used for the total knee replacement (TKR) may have a risk of failures caused by pressure and stress concentrated on the tibial post.
Femoral stem varus has been associated with poorer results. We report the incidence of varus/valgus
Introduction. Torsional
Background. The purpose of this study was to analyze the effect of femorotibial alignment (FTA), femoral and tibial component alignment, correction of
Femoral shaft fractures are fairly common injuries in paediatric age group. The treatment protocols are clear in patients of age less than 4 years and greater than 6 years. The real dilemma lies in the age group of 4–6 years. The aim of this study is to find whether a conservative line should be followed, or a more aggressive surgical intervention can provide significantly better results in these injuries. This study was conducted in a tertiary care hospital in Bhubaneswar, India from January 2020 to March 2021. A total of 40 patients with femur shaft fractures were included and randomly divided in two treatment groups. Group A were treated with a TENS nail while group B were treated with skin traction followed by spica cast. They were regularly followed up with clinical and radiological examination to look out for signs of healing and any complications. TENS was removed at 4–9 months’ time in all Group A patients. Group A patients had a statistically significant less hospital stay, immobilisation period, time to full weight bearing and radiological union. Rotational malunions were significantly lower in Group A (p-value 0.0379) while there was no statistically significant difference in angular malunion in coronal and sagittal plane at final follow up. Complications unique to group A were skin necrosis and infection. We conclude that TENS is better modality for treatment of shaft of femur fractures in patients of 4–6 years age as they significantly reduce the hospital stay, immobilization period and rotational
Numerous dynamic studies have evaluated the tibiofemoral contact pressures that follow total knee arthroplasty (TKA), and several static studies utilizing finite elements and pressure sensitive film have evaluated
The objective of this study was to compute the in vivo dynamic tibiofemoral contact forces for normal alignment, and then evaluate the change in contact forces and pressures with increasing varus-valgus and internal-external rotational
The Q angle is defined as the angle formed by a line passing from the anterior-superior iliac spine and the centre of the patella and another line passing this point to the centre of the tibial tuberosity. Normal values reported in the literature for the Q angle widely range between 12.7° (± 0.72°) and 18.8° (± 4.7°). This variability depends on individual anatomical variations and method of measurement as well. In fact, several factors can affect the measurement of Q angle. The correct evaluation is carried out with a goniometer, in supine position and the knee in full extension. Q angle evaluation can be biased by standing position and quadriceps contraction, which can increase the Q angle; in contrast, knee flexion can reduce it. Furthermore, it has been demonstrated that the Q angle increases from external to internal rotation of the tibia, while it decreases from pronation to supination of the foot. Finally, patellar