Joanna Sikorska

A Framework to Assess Data Quality for Reliability Variables

This paper presents a framework for assessing the impact of the data collection process on the validity of key measures in reliability. The quality of data is affected by many organisational and behavioural factors. The aims of developing this framework are to (1) identify inputs/steps that have the most significant impact on the quality of key performance indicators such as MTTF (mean time to failure) and MTTR (mean time to repair), (2) identify ‘weak’ links in the data collection process, and (3) identify potential remedial actions. Development of this framework will assist the understanding of assumptions used in reliability calculations and improve the quality of underlying data and the data collection process. Consequently, this is a vital step in the continued development and use of data based decision-making models for reliability assessment.

Relative Risk of Different Operations for Medial Compartment Osteoarthritis of the Knee

The relative risk of total knee arthroplasty (TKA), high tibial osteotomy (HTO), and medial unicompartment (UKA) replacement for medial compartment arthritis is presented. Risk is defined as the product of the probability of an event occurring and its consequence. To define consequence, 2 related scales of impact (1 systemic and 1 local) are suggested. The probability of a complication is derived from the incidence as found in the published literature and expressed as a decimal of 1. The cumulative risk is expressed as the sum of the risks of all individual complications. The overall impact of specific comorbidities has been calculated when their influence on the incidence of a particular complication is known. Of the 3 operations, TKA has the highest cumulative risk of systemic complications and HTO is the most likely to produce local technical problems. UKA is the safest of the procedures. The relative risk of TKA:HTO:UKA is 1.00:1.01:0.31. For TKA, the greatest additional risk is morbid obesity, which increases overall risk by 31% by virtue of a 7.8-fold increase in infection rate. Cardiorespiratory disease, diabetes mellitus, smoking, and cirrhosis of the liver increase cumulative risk by 20%, 17%, and 17%, respectively.The authors conclude that a quantitative assessment of operative risk is possible and useful. However, it depends on the availability of reliable complication incidence data.