Association of patellofemoral morphology and alignment with the radiographic severity of patellofemoral osteoarthritis

Background Risk factors for the severity of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA. Methods A retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic grade of PFOA and tibiofemoral osteoarthritis (TFOA), lateral and medial trochlear inclination angle, sulcus angle, and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG) and patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters, and the relationships between each of these measures and the severity of PFOA were investigated. Results By studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P < 0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle; and type I patella was 8.80 (p = 0.043), 16.51 (P < 0.001), 0.04 (P < 0.001), and 0.18 (p = 0.048) respectively. Conclusions Extreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.

Relationship of Patellofemoral Osteoarthritis to Changes in Performance-Based Physical Function Over 7 Years: The Multicenter Osteoarthritis Study

Objective Determine the relationship of patellofemoral osteoarthritis (OA) to changes in performancebased function over 7 years. Methods 2666 participants (62.2±8.0 years, BMI 30.6±5.9kg/m2; 60% female) from the Multicenter Osteoarthritis Study with knee radiographs at baseline and who completed repeated chair stands and 20- meter walk test at baseline, 2.5, 5, and 7 years were included. Generalized linear models assessed the relation of radiographic patellofemoral OA and radiographic patellofemoral OA with frequent knee pain to longitudinal changes in performance-based function. Analyses were adjusted for age, sex, BMI, tibiofemoral OA, and injury/surgery. Results Linear models demonstrated a significant group by time interaction for the repeated chair stands (p=0.04) and the 20-meter walk test (p<0.0001). Those with radiographic patellofemoral OA took 1.01seconds longer on the repeated chair stands (p=0.02) and 1.69seconds longer on the 20-meter walk test (p<0.0001) at 7 years compared with baseline. When examining the relation of radiographic patellofemoral OA with frequent knee pain to performance-based function there was a significant group by time interaction for repeated chair stands (p=0.05) and the 20-meter walk test (p<0.0001). Those with radiographic patellofemoral OA with frequent knee pain increased their time on the repeated chair stands by 1.12seconds (p=0.04) and 1.91seconds (p<0.0001) on the 20-meter walk test over 7 years. Conclusion Individuals with radiographic patellofemoral OA and those with radiographic patellofemoral OA with frequent knee pain have worsening of performance-based function over time. This knowledge may present opportunities to plan for early treatment strategies for patellofemoral OA to limit functional decline over time.

Association of Patellofemoral Morphology and Alignment With the Radiographic Severity of Patellofemoral Osteoarthritis

Background: Risk factors for the progression of patellofemoral osteoarthritis (PFOA) are poorly understood. This research aims to evaluate the association between patellofemoral joint (PFJ) morphology and alignment with the radiographic severity of PFOA.Methods: A retrospective analysis of CT scan and lateral radiograph data were acquired in patients with PFOA. The radiographic severity of PFOA and tibiofemoral OA (TFOA), lateral and medial trochlear inclination angle, sulcus angle and the Wiberg classification of patella morphology, the congruence angle, patellar tilt angle, and lateral patellar angles, and tibial tubercle trochlear groove distance (TT-TG), patella height (i.e., Caton-Deschamps index) were assessed using CT scans and sagittal radiographs of the knee. All the PFJ morphology and alignment data were divided into quarters and the relationship between each measure and the severity of PFOA was investigated.Results: By studying 150 patients with PFOA, we found a U-shaped relationship between the Caton-Deschamps index and the severity of PFOA (P <0.001). A lower value of sulcus angle and lateral patellar angle, a higher value of congruence angle, and type III patella were associated with more severity of lateral PFOA. Compared with the highest quarter of each measure, the adjusted odds ratios (OR) of the severity of PFOA in the lowest quarter of sulcus angle, lateral patellar angle, and congruence angle, and type I patella was 8.80 (p=0.043), 16.51 (P <0.001), 0.04(P <0.001), and 0.18 (p=0.048) respectively.Conclusions: Extreme value of patella height, a higher value of lateral patellar displacement and lateral patellar tilt, lower value of sulcus angle, and type III patella were associated with more severity of PFOA.