Association of patella alta with worsening of patellofemoral osteoarthritis-related structural damage: data from the Osteoarthritis Initiative

Abstract

s u m m a r yObjectives: To determine the association between Insall-Salvati ratio (ISR), a measure of patella alta, and worsening of Magnetic Resonance Imaging (MRI)-based osteoarthritis (OA)-related patellofemoral joint structural damages over 24-month in participants of the Osteoarthritis Initiative (OAI). Design: Using weighted random sampling method, we selected a sample of 500 knees (from 1,677 knees with available baseline and 24-months MRI OA Knee Score (MOAKS) measurements), which is OAIrepresentative regarding knee OA-related factors (i.e., baseline age, sex, body mass index (BMI), and radiographic KellgreneLawrence grading). The ISR was measured in all enrolled knees using baseline sagittal 3T-MRI plane by three radiologists. Baseline and 24-month MOAKS variables for patellofemoral bone marrow lesions (BMLs), cartilage damages, and osteophytes were extracted, and the associations between ISR and 24-month worsening of these 3T-MRI features were evaluated using multivariable regression models. After computing receiver operating characteristic curves, the optimal cutoff point of ISR for indicating worsening of patellofemoral OA was determined. P-values were adjusted for multiple comparisons and false discovery rate (FDR) adjusted P-values were reported. Results: In this longitudinal analysis, 24-month worsening of BML (odds ratio [OR] (95% confidence interval [95% CI]):11.18 (3.35e39.6), adjusted-p-value:<0.001) and cartilage scores (OR:7.39 (1.62e34.71), adjusted-p-value:0.042) in lateral patella was associated with higher baseline ISR. However, higher ISR was not statistically associated with medial patellar or medial and lateral trochlear BML or cartilage scores worsening. We determined the optimal cutoff point of ISR!1.14 (95% CI: 1.083e1.284) for predicting lateral patellofemoral OA-related structural damages worsening over 24-months (sensitivity:73.73%; specificity: 66.67%). Conclusions: Given the uncertainly surrounding the results, our overall findings suggest that ISR could be considered as a predictor of lateral patellofemoral OA-related structural damages worsening with the optimal cutoff point of !1.14 using knee sagittal MRI measurements.

Osteoarthritis year in review 2019: imaging

“…Factors found to be associated with the progression of tibiofemoral OA include frontal plane malalignment on Xrays 29,30 , decreased bone mineral density on DXA 31 , effusion and synovitis 32e34 , mucinous changes in the anterior cruciate ligament (ACL) 35 , bone marrow edema lesions 34 , elevated cartilage T2 relaxation time 34 , trabecular microstructure deterioration 31 , and increased thigh muscle fat 36 on MRI, quadriceps muscle weakness 37 , hip abductor muscle weakness 38 , and knee pain39. Factors found to be associated with the progression of patellofemoral OA include frontal plane malalignment on X-rays 29 , patella alta 40 , tibia tuberosity to trochlear groove distance 41 , superolateral Hoffa's fat fad edema 42 , and meniscus tear and extrusion 43 on MRI, and quadriceps muscle weakness 44 . Kretzschmar et al found that elevated cartilage T2 relaxation time was a risk factor for the future onset of morphologic cartilage lesions within the knee joint.…”

Evaluating risk factors involved in the alteration of biomechanics in relation to knee osteoarthritis

“…Given that obesity has the potential of being reduced, it is possible to propose a physical exercise program and a rigorous diet (19,20). The findings of a recent study on the influence of changes in patellar position in patellofemoral osteoarthritis, using magnetic resonance investigations, conclude that patella alta is a predictive factor for lateral patellofemoral osteoarthritis (21). In the analyzed group, patients with knee osteoarthritis presented patella alta with a frequency of 91.82% on the left and 90.24% on the right.…”

A quantitative MRI investigation of the association between iliotibial band syndrome and patellofemoral malalignment

“…Anatomic risk factors for lateral patellar instability include patella alta, increased lateral patellar tilt, and trochlear dysplasia (30). Previous studies have shown that patella alta, lateral displacement and patella tilt, and superolateral Hoffa's fat pad edema are all associated with the occurrence and development of patellofemoral osteoarthritis (31)(32)(33)(34)(35). Haj-Mirzaian et al (33) reported that the optimal cutoff point of the Insall-Salvati ratio as a predictor of lateral patellofemoral osteoarthritis was ≥1.14, which is still within the normal range (0.8-1.2).…”

“…Previous studies have shown that patella alta, lateral displacement and patella tilt, and superolateral Hoffa's fat pad edema are all associated with the occurrence and development of patellofemoral osteoarthritis (31)(32)(33)(34)(35). Haj-Mirzaian et al (33) reported that the optimal cutoff point of the Insall-Salvati ratio as a predictor of lateral patellofemoral osteoarthritis was ≥1.14, which is still within the normal range (0.8-1.2). So, both ITBS and superolateral Hoffa's fat pad edema may be correlated with underlying patellofemoral malalignment but may present different injury patterns.…”