Current Data Do Not Support Routine Use of Patient-Specific Instrumentation in Total Knee Arthroplasty

The purpose of this systematic review and meta-analysis is to compare patient-specific instrumentation (PSI) versus standard instrumentation for total knee arthroplasty (TKA) with regard to coronal and sagittal alignment, operative time, intraoperative blood loss, and cost. A systematic query in search of relevant studies was performed, and the data published in these studies were extracted and aggregated. In regard to coronal alignment, PSI demonstrated improved accuracy in femorotibial angle (FTA) (P = 0.0003), while standard instrumentation demonstrated improved accuracy in hip-knee-ankle angle (HKA) (P = 0.02). Importantly, there were no differences between treatment groups in the percentages of FTA or HKA outliers (>3 degrees from target alignment) (P = 0.7). Sagittal alignment, operative time, intraoperative blood loss, and cost were also similar between groups (P > 0.1 for all comparisons).     

Initial Stability of Press-Fit Acetabular Components Under Rotational Forces

The primary goal of this study was to determine the initial press-fit stability in acetabular components without screw fixation. Mechanical testing was performed with the implantation of press-fit acetabular components in cadaveric specimens. No significant difference was found in load to failure testing between 1 and 2 mm of under-reaming. However, there was significant variability in bending forces required to create 150 μm of micromotion ranging from 49.3 N to 214.4 N. This study shows that cups implanted in a press-fit fashion, which are felt to be clinically stable, have high degrees of variability in resisting load and may be at risk for loosening. There is a need for more objective intra-operative techniques to test cup stability.     

A new way of caring for older people in the community

The government's modernisation agenda is challenging traditional practice by introducing new roles and concepts to meet the increasing healthcare needs of the older population and those with long-term conditions. Over the past two years several national pilots have been trialled to examine different models of managing care for these groups. One is the Evercare model, a case management approach to the delivery of care in the community for older people. This article focuses on a cohort of 12 nurses from three local primary care trusts who participated in the national Evercare pilot project from July 2003-April 2005. It examines the context for change, explores and appraises the development of a new role, and evaluates the educational partnership developed with a local university.     

Electrical Impedance Myography in the Assessment of Disuse Atrophy

Tarulli AW, Duggal N, Esper GJ, Garmirian LP, Fogerson PM, Lin CH, Rutkove SB. Electrical impedance myography in the assessment of disuse atrophy.

Objective

To quantify disuse atrophy using electrical impedance myography (EIM), a noninvasive technique that we have used successfully to study neurogenic and myopathic atrophy.

Design

We performed EIM of the tibialis anterior of subjects with disuse atrophy secondary to cast immobilization and in their contralateral normal leg. Subjects were studied shortly after cast removal and again several weeks to months after the cast was removed and normal mobility was restored.

Setting

Outpatient neurology and orthopedic practices at a tertiary care medical center.

Participants

Otherwise healthy subjects (N=10) with unilateral leg fracture.

Interventions

Not applicable.

Main Outcome Measures

Resistance, reactance, and phase measured at 50kHz.

Results

The main EIM outcome parameter, phase at 50kHz, was lower in the immobilized leg in 9 of 10 cases. Additionally, when normal mobility was restored, the phase of the casted leg increased relative to its initial measurement in all 10 cases, while it increased inconsistently in the contralateral leg.

Conclusions

EIM may be a powerful tool for the assessment of disuse atrophy.