Identification of the medial femoral safe zone for drilling during dynamic hip screw side plate fixation: A CT angiogram tracing of the profunda femoris artery

Objectives

Iatrogenic injury of the Profunda Femoris Artery (PFA) at time of hip fixation surgery can increase morbidity and mortality and prolong the hospital stay. This is an injury that tends to pass unnoticed as a cause of postoperative deterioration despite being frequently reported in the literature. Our study aims to describe the anatomy of the PFA in relation to the medial femoral cortex with specific emphasis on its orientation relative to the position of a sliding hip screw side plate construct. By doing so we are able to present clear guidance to orthopaedic surgeons on how to avoid iatrogenic PFA injury at the time of hip fracture fixation.

A comparison of union rates and complications between single screw and double screw fixation of sliding calcaneal osteotomy

Background

The number of screws used for sliding calcaneal osteotomy fixation has not been examined in the literature. The purpose of this paper is to examine this topic.

Distal medial tibial locking plate for fixation of extraarticular distal humeral fractures; an alternative choice for fixation

Objective

The aim of this study was to describe an alternative fixation method for distal humeral extra-articular fractures through posterior approach using distal tibia anatomic locking plate; and to evaluate the patient's functional outcome and union condition.

Biomechanical evaluation of sacroiliac joint fixation with decortication

Background Context

Fusion typically consists of joint preparation, grafting, and rigid fixation. Fusion has been successfully used to treat symptomatic disruptions of the sacroiliac joint (SIJ) and degenerative sacroiliitis using purpose-specific, threaded implants. The biomechanical performance of these systems is important but has not been studied.

Anterior cruciate ligament reconstruction with a multistrand hamstring graft fixed with a Ligament Tension Screw: a new device that can be used to readjust graft tension after fixation

We developed a new fixation device for reconstruction of the anterior cruciate ligament with a multistrand hamstring graft. This device allows the graft tension to be readjusted after fixation. This device, called a Ligament Tension Screw, consists of three parts, a screw, a washer, and a post. To create the graft, the tendons were formed into a loop. The device was hung from one end of the loop of the graft and a Kennedy-ligament augmentation device (LAD) artificial ligament was hung at the other end. The Kennedy-LAD artificial ligament was used extraarticularly for fixation at the tibia with double staples. Graft tension was increased by turning the screw, which pulls on the post suspending the graft. Fifty-two patients were evaluated after a minimum 2-year follow-up. The evaluation included physical examination, stability measurement with a KT2000 arthrometer, a Cybex muscle strength measurement, a functional test, and scoring of the knee according to the International Knee Documentation Committee (IKDC). Pivot test was negative in 47 patients (91%), but glide occurred in 5 patients (9%). No patient had a "clunk" or markedly poor result on the pivot test. All patients recovered full extension. Seven patients lost full flexion, but the loss of flexion was less than 5° in all seven. The KT 2000 arthrometer measurement with 133 N anterior drawer force indicated that 46 patients (88%) had less than 3-mm side-to-side difference. The mean muscle strength of the quadriceps and hamstrings was 91% and 94%, respectively, compared with the findings in the contralateral limb. The functional test showed a one-leg hop distance equal to 94% of that the opposite side. According to the final IKDC evaluation, 48 patients were graded as normal or nearly normal, and 4 patients as abnormal; none was severely abnormal. This study demonstrated satisfactory results for the reconstruction with a multistrand hamstring graft fixed with the new Ligament Tension Screw. Received: February 15, 2001 / Accepted: July 30, 2001     

Impaired suppression of vestibular nystagmus by fixation in cerebellar and noncerebellar patients

Summary The suppression of vestibular nystagmus (VN) by fixation of a small visual target moving with the observer was tested while subjects seated on a rotatable chair were oscillated at 0.1 Hz and peak accelerations of +-10 to 130°/s². Total amplitudes of nystagmus during movement towards one direction occurring despite intended fixation were compared to slow phases of optokinetic nystagmus (OKN) and smooth pursuit (SP) towards the opposite direction.Supported by the Deutsche Forschungsgemeinschaft, SFB 70 (Hirnforschung und Sinnesphysiologie)     

The influence of rapid prism adaptation upon fixation disparity.

Small errors of fusional vergence (fixation disparity) were examined as a function of the magnitude of horizontal prism stimulating convergence or divergence for a short (30sec) duration. Marked differences were observed between the amplitude of fixation disparity resulting from convergent and divergent stimulus disparities. In another experiment, subjects wore a horizontal prism for 30 sec after which time one eye was occluded for 40 sec. Measurements of vergence eye movements revealed an incomplete relaxation of fusional vergence (prism adaptation) after 40 sec of occlusion. Marked differences were observed between the amplitude of prism adaptation resulting from convergent and divergent stimuli. Maximum prism adaptationand minimum fixation disparity occurred with the same direction of prism, suggesting that a slow fusional vergence mechanism minimizes errors of binocular vergence.     

The accuracy of binocular vergence for peripheral stimuli

Two experiments were conducted to investigate the roles of dark vergence and retinal eccentricity as factors influencing binocular vergence responses. A nonius alignment technique was used to measure vergence responses in total darkness (dark vergence) and for dim binocular stimuli presented at retinal eccentricities ranging from 2° to 8° over distances ranging from 28.5 to 342cm. The results indicate that vergence was progressively less accurate with stimuli at increasing retinal eccentricities and that errors of fixation were biased toward the individual's dark vergence position. The hypothesis that dark vergence represents the functional resting state of the vergence system which influences oculomotor fusional responses under a variety of conditions is discussed.     

Characteristics of saccadic intrusions

Primary fixation is never perfectly stable, but is frequently interrupted by slow drifts, microsaccades and saccadic intrusions (SI). SI are involuntary, conjugate movements which take the form of an initial fast movement away from the desired eye position and followed after a short duration, by either a return secondary saccade or a drift. The purpose of this study was to examine the prevalence and metrics of SI in a population of 50 healthy subjects. Using both one and two dimensional recordings we find that all 50 members of the subject group exhibited SI. The SI were bilateral, conjugate and horizontal. No purely vertical SI were detected when examined in three subjects. SI amplitude mean and range was 0.6° ± 0.5°, 0.1°-4.1°; SI frequency mean and range was 18.0 ± 14.3 per min, 1.0-54.8 per min; SI duration mean and range was 225 ± 150, 20-870 ms. The mean SI amplitude and frequency when SI < 0.5° were removed was 0.97° ± 0.56° and 7.0 ± 11.4 per min respectively. Age was positively correlated with SI amplitude (p < 0.01), but there was no correlation between age and SI frequency. Three of four types of SI monophasic square wave intrusions (MSWI), biphasic square wave intrusions (BSWI) and double saccadic pulses (DSP) were found to be exclusively saccadic, whilst the fourth type, the single saccadic pulses (SSP), were confirmed to exhibit a slow secondary component. MSWI were the most frequently observed SI occurring in 47 out of 50 (94%) of the subjects with a mean amplitude, frequency and duration of 0.7° ± 0.5°, 11.5 ± 11.6 per min, and 255 ± 147 ms respectively. Mean amplitudes and frequencies for BSWI (n = 20), SSP (n = 11) and DSP (n = 34) were found to be 0.50° ± 0.2°, 1.2 ± 2.5 per min; 0.40° ± 0.20°, 0.4 ± 1.0 per min and 0.3° ± 0.4°, 5.0 ± 8.7 per min respectively. No differences in MSWI characteristics were found between binocular and monocular viewing. Possible explanations for SI occurrence include experimental viewing conditions, subject fatigue and covert shifts in attention.