Precision of Cup Positioning Using a Novel Computed Tomography Based Navigation System in Total Hip Arthroplasty.

: Navigation systems are designed to enhance surgical precision, improving patient outcomes and reducing the risk of implant misplacement. In this study, we have evaluated a novel orthopedic surgical platform that utilizes CT imaging with AI-based algorithms to automate several critical aspects of total hip arthroplasty. It contains three modules-preoperative planning, navigation during surgery, and follow-up analysis.

A New CT Method for Assessing 3D Movements in Lumbar Facet Joints and Vertebrae in Patients before and after TDR.

This study describes a 3D-CT method for analyzing facet joint motion and vertebral rotation in the lumbar spine after TDR. Ten patients were examined before and then three years after surgery, each time with two CT scans: provoked flexion and provoked extension. After 3D registration, the facet joint 3D translation and segmental vertebral 3D rotation were analyzed at the operated level (L5-S1) and adjacent level (L4-L5).

Motion analysis of total cervical disc replacements using computed tomography: preliminary experience with nine patients and a model.

Background: Cervical total disc replacement (CTDR) is an alternative to anterior fusion. Therefore, it is desirable to have an accurate in vivo measurement of prosthetic kinematics and assessment of implant stability relative to the adjacent vertebrae.

Purpose: To devise an in vivo CT-based method to analyze the kinematics of cervical total disc replacements (CTDR), specifically of two prosthetic components between two CT scans obtained under different conditions.

Quality of life after a subtrochanteric fracture: a prospective cohort study on 87 elderly patients.

Background: The subtrochanteric fracture constitutes approximately 5-10% of all hip fractures. This particular fracture type, owing to its configuration and instability, poses significant challenges to the fixation method, especially in elderly patients with varying degrees of osteoporosis. There has been a gradual change in the operative techniques used to stabilise these fractures leading to the current widespread use of cephalomedullary nails.

Health related quality of life outcome instruments.

Health is the most significant part of quality of life. Generally, quality of life outcome instruments used in healthcare confine their attention to health related areas, assessing health related quality of life. The present study aims to describe some commonly used health profile instruments such as the generic measures SF-36, Nottingham Health Profile and Sickness Impact Profile; and the preference-based measures EuroQol and SF-6D.

Back extensor muscle fatigue in patients with lumbar disc herniation. Pre-operative and post-operative analysis of electromyography, endurance time and subjective factors.

We investigated back muscle fatigue and endurance in patients with lumbar disc herniation before and after surgery, and established the degree of association between perceived fatigue and objectively measured fatigue. Additionally, the relationships between muscle fatigue and endurance time on the one hand, and activity, participation, self-efficacy and health on the other, were investigated to clarify the grades of association between these factors. Forty-three consecutive patients with lumbar disc herniation were tested before surgery and 4 weeks after surgery.

Spinal stenosis re-operation rate in Sweden is 11% at 10 years--a national analysis of 9,664 operations.

Re-operation rates in spinal stenosis surgery vary between 5 and 23%. Most previous studies have been based on selected patients groups. We analysed the 10-year lumbar spinal stenosis re-operation rate from comprehensive Swedish national data during 1987-1999.

EMG recovery and ratings after back extensor fatigue in patients with lumbar disc herniation and healthy subjects.

This prospective study aimed to examine whether patients with lumbar disc herniation, before and after surgery, showed impaired recovery from fatigue measured with EMG and subjective ratings as compared to healthy subjects. Forty-three patients due for, and after, lumbar disc surgery and 60 healthy subjects were fatigued using a modified Sørensen's test. Recovery of back extensor muscles was assessed using electromyography and the Borg scale ratings at 1, 2, 3, and 5 minutes of recovery, and was further analyzed using an exponential time-dependence model.

Lumbar muscle fatigue and recovery in patients with long-term low-back trouble--electromyography and health-related factors.

Objective: The aim was to explore the validity and reliability of EMG for assessing lumbar muscle fatigue.

Design: Patients with long-term low-back trouble (n=57) were compared to a healthy reference group (n=55). Back muscle fatigue and recovery were studied in relation to health-related factors.

Electromyographic and biomechanic analysis of anterior cruciate ligament deficiency and functional knee bracing.

Objective: Examine the neuromuscular response to functional knee bracing relative to anterior tibial translations in vivo.

Design: During randomised brace conditions, electromyographic data with simultaneous skeletal tibiofemoral kinematics were recorded from four anterior cruciate ligament deficient subjects to investigate the effect of the DonJoy Legend functional brace during activity.

Background: Knee braces do not increase knee stability but may influence afferent inputs from proprioception and therefore one might expect changes in muscle firing patterns, amplitude and timing.

Recovery of electromyograph median frequency after lumbar muscle fatigue analysed using an exponential time dependence model.

The recovery of the median frequency of the power spectrum of the electromyogram (EMG) after fatigue has been studied to obtain reference data for healthy subjects (n = 55). In a seated position, the subjects performed a 45 s isometric back muscle contraction at 80% of maximal voluntary contraction, followed by 5 s contractions after 1, 2, 3, and 5 min in the recovery phase. In an additional reliability study (n = 11), this was performed six times.

Seeking care for low back pain in the general population: a two-year follow-up study: results from the MUSIC-Norrtälje Study.

Study Design: A 2-year follow-up study was conducted to investigate new patients who sought care for low back pain from all the caregivers in a specific region with a population of approximately 17,000 men and women ages 20 to 59 years.

Objectives: To describe care-seeking behavior for low back pain in a general population; to characterize pain, disability, and sick leave among the patients; and to study predictors of recovery. An additional aim was to find a simple way of classifying low back pain in epidemiologic studies.

Tibiofemoral contact points relative to flexion angle measured with MRI.

Objective: To determine whether knee flexion influenced bony contact movements during flexion.

Design: Accurate three-dimensional (3D) measurements of tibiofemoral bony contact points in vivo was performed using magnetic resonance imaging technology at 0 degrees, 30 degrees and 60 degrees of flexion.

Background: Magnetic resonance imaging is an accurate non-invasive tool for visualizing muscles, tendons, and bone, and provides precise 3D co-ordinates.

Influence of interelectrode distance and force level on the spectral parameters of surface electromyographic recordings from the lumbar muscles.

In order to study the influence of interelectrode distance and force level on the electromyographic (EMG) spectral parameters and on their reliability, bipolar surface EMG measurements were performed on the lumbar muscles of 15 subjects. Two test contractions (45 s) at 40% of maximal voluntary contraction (MVC) were performed, one with 2 cm interelectrode distance and the other with 4 cm, followed by two contractions at 80% MVC with the same change in interelectrode distance. Increasing the interelectrode distance from 2 to 4 cm caused a significant mean decrease (about 8%) in the initial median frequency.

Electromyography and ratings of lumbar muscle fatigue using a four-level staircase protocol.

Objective: The purpose of the study was to explore whether a relationship existed between subject's experience and objective measurements of back-muscle fatigue in healthy subjects. This may be used as reference material later.

Design: Muscle fatigue in the lower back was measured in healthy subjects using a staircase protocol.