Measurement of varus/valgus alignment in obese individuals with knee osteoarthritis

Abstract

Objective. Frontal plane knee malalignment may increase progression of knee osteoarthritis (OA) and hasten functional decline. An accurate nonradiographic measure of knee alignment is necessary because the gold standard measure, the long-leg radiograph, is costly and often unavailable. Moreover, nonradiographic measures of knee alignment have not been validated in an obese population, where knee OA is common. The purpose of this study was to develop and assess the concurrent validity and reliability of a nonradiographic measure of frontal plane knee alignment and demonstrate the accuracy of the measure in an obese population. Methods. Fifty-five subjects (41 women, 14 men; mean ؎ SD age 62.9 ؎ 10.3 years) with knee OA were examined. A nonradiographic measure (umbilical method) of frontal plane alignment, using the landmarks of the umbilicus, knee, and ankle, was compared with the radiograph gold standard. Statistical significance was accepted at P < 0.05. Results. Eighty-nine percent of the participants had a body mass index (BMI) placing them in the overweight or obese category (mean ؎ SD BMI for all subjects 31.3 ؎ 6.1 kg/m 2 ). Radiographic measures of alignment ranged from 9.1°valgus to 14.3°varus (76% of the participants had varus alignment, 12% had valgus alignment, and 2% had neutral alignment). Umbilical measures ranged from 1°valgus to 21°varus. The umbilical measure was significantly correlated with the radiographic method (r ‫؍‬ 0.75, P < 0.001). The error of the umbilical measure was not significantly correlated with the BMI (r ‫؍‬ ؊0.21, P ‫؍‬ 0.13). Conclusion. The umbilical method of assessing frontal plane knee alignment is a valid surrogate for the radiographic gold standard and retains its accuracy in an obese population.

Sensitivity of different measures of frontal plane alignment to medial and lateral joint space narrowing: From the osteoarthritis initiative

“…Concurrent validity between measurement methods was modest and consistent with previous studies [5][6][7][8][9][10][11]15,26], and correlations were similar when stratifying for sex and JSN. IranpourBoroujeni et al [12] reported correlations with HKA using the traditional FTA method (r ¼ 0.68) and the new FTA method (r ¼ 0.75), which were larger than those reported in the present study.…”

“…However, prior studies have highlighted its inconsistent correlations with the gold standard and traditional FTA measures (r: 0.32-0.75) [5,6,8,9,15], likely because of the low precision and large random noise of the measurement. Evaluating the relationships between goniometry and radiographic measures of alignment categorized by different directions and magnitude of uni-compartmental JSN, however, may demonstrate whether or not clinicians can utilize non-radiographic measures of alignment to identify participants with compartment-specific knee OA and/or at risk for subsequent structural progression.…”

“…Frontal plane alignment is commonly determined by weight-bearing radiography, either using standing full limb films to quantify mechanical alignment (hip-knee-ankle angle, HKA) or short knee films to quantify anatomical alignment (femorotibial angle, FTA). Although short knee films are more readily available across clinical settings and involve smaller radiation exposure, full limb films also capture the anatomical characteristics of the hip and ankle and therefore are considered the gold standard and most accurate method for evaluating alignment [5][6][7][8][9].…”

Osteoarthritis – the role of cartilage and capability of modification of the course of disease

“…Spośród ok. 13% 60-latków, u których wykazano kliniczne i radiologiczne objawy artrozy kolan, w następnej dekadzie zaawansowana lub krańcowa artroza rozwinie się u ponad 20% [2]. W przypadku osób otyłych ryzyko rozwoju zmian zwyrodnieniowych zwiększa się 3-krotnie [3]. Biorąc pod uwagę zasięg i powszechność osteo artrozy, niezwykle niepokojące są statystyki odnoszące się do jej następstw.…”

Osteoarthritis of the knee and hip. Part I: aetiology and pathogenesis as a basis for pharmacotherapy

“…Among those surviving into the next decade, 20% will have symptomatic advanced or end‐stage knee OA. Obese subjects will have a three‐fold higher incidence of knee OA than the non‐obese [26] . Use of magnetic resonance imaging (MRI) may increase the sensitivity of detection and assessment of progression of knee OA [27] …”