Objective assessments of medial osteoarthritic knee severity by MRI: new computer software to evaluate femoral condyle contours

Abstract

An irregular contour of the medial femoral condyle (MFC) on magnetic resonance imaging (MRI) appears to indicate the severity of medial-type knee osteoarthritis (OA). The purpose of this study was to establish a system to enable objective assessments of OA knee severity using newly developed software that semiautomatically measures irregularity of the MFC. (1) We evaluated 48 patients aged 50-83 years with 55 knees of medial-type OA. The following scores were recorded: Lysholm score, visual analogue scale (VAS) and the Japanese Knee Osteoarthritis Measure (JKOM). MFC irregularity was automatically calculated by newly programmed computer software. Four parameters for condyle irregularity were calculated: (a) the average thickness of the contour (ATC), (b) the ratio of the upper surface length to the lower surface length of the contour (RUL), (c) average squared thickness of the contour (ASTC) and (d) standard deviation of the contour thickness (SDC). (2) Nine knees that underwent total knee arthroplasty were further analysed histopathologically and compared with irregularity score. Statistically, the RUL and SDC were significantly correlated with the Lysholm score, VAS and JKOM, with good reliability. Histological examinations showed that an irregular contour reflected the density of cystic lesions formed in subchondral bone. An irregularity of MFC on MRI is correlated with OA disease severity clinically and histopathologically. The new computer software is useful to objectively assess OA disease severity.

A systematic review of the relationship between subchondral bone features, pain and structural pathology in peripheral joint osteoarthritis

“… NA High (71) Torres 2006 [ 103 ] MRI attrition, (WORMS) TFJ and PFJ (C) Pain VAS (C) Nil Coefficient 3.33, 95 % CI 1.79 to 4.87 Coefficient 1.91, 95 % CI 0.68 to 3.13 + High (68) MRI bone attrition - case−control studies Javaid 2012 [ 139 ] Baseline semi-quantitative MRI attrition size (WORMS) (C) TFJ and PFJ Presence of frequent knee pain (C) after 2 years Nil OR 2.40, 95 % CI 1.51 to 3.83 NR + Low (59) MRI bone shape/dimension - cohort studies Everhart 2014 [ 114 ] Baseline TFJ subchondral surface ratio of medial and lateral TFJ compartments (C) Incident frequent knee pain at 48 months, (L) Sex, race, age, BMI, tobacco use, activity level, knee coronal alignment, baseline symptoms, injury history, surgery history, KL grade, and JSW NR Medial SSR OR 0.48, 95 % CI 0.30 to 0.75, p = 0.0009. Lateral SSR OR 1.27, 95 % CI 0.86 to 1.88, p = 0.19 - larger MSSR gets less incident frequent knee pain High (61) MRI bone shape/dimension - cross-sectional studies Ochiai 2010 [ 47 ] MRI irregularity of femoral condyle contour (C) Knee pain VAS (C) Nil Irregularity of femoral condyle contour r = 0.472, p = 0.0021 NR + Low (50) MRI bone cyst - cohort studies Sowers 2011 [ 28 ] Semi-quantitative MRI bone cyst size in TFJ (C) Increasing WOMAC pain (L) Nil NR NR analysis described as not significant but data not shown NA Low (53) MRI bone cyst - cross-sectional studies Kornaat 2006 [ 130 ] Semi-quantitative MRI bone cyst(C) Chronic pain presence (C) Nil NR Patellofemoral OR 1.83, 95 % CI (0.80 to 4.16) NA H...…”

“…MRI (one cohort, one cross-sectional study): one prospective, well-adjusted, high quality analysis found the femoro-tibial articulating surface mismatch was associated with incident frequent knee pain [ 114 ]. One unadjusted cross-sectional analysis found the irregularity of the femoral condyle surface was associated with severity of knee pain [ 47 ]. In summary, specific features of bone shape are independently associated with incident frequent knee pain and severity of pain.…”

<b>Medial knee contact force and dysfunction in the elderly</b>

“…This study analyzed the relation between the medial knee contact force during the stance phase and knee pain and dysfunction in elderly subjects, using musculoskeletal simulation analysis and a self-reported knee function measure JKOM to have context of life style for Japanese elderly. The total JKOM score was reported to be 50−60 for patients with mild and moderate osteoarthritis (Kellgren and Lawrence grade I and II) 21,22) . The median total JKOM score for our pain group subjects was 7.5 (range, 1−37); therefore, they had very mild knee dysfunction.…”

Linking Bone Changes in the Distal Femur to Functional Deficits

“…Since MRI images depicting bone are known to be accurately related to the macroscopic appearance of denuded bone (Cohen et al ., ; Iwaki et al ., ; Woodhead et al ., ; Leitzes et al ., ; Louis et al ., ; Ochiai et al ., ), a grading system that is equally applicable to clinical and archaeological skeletal populations was developed. This new system, the Clinical Archeological Osteoarthritis Scale (CAOS), was used to grade the degree of knee OA visible in MRIs and focused on features previously identified as significant in the Kellgren & Lawrence () and Rogers et al .…”