In‐vivo patellar tracking in individuals with patellofemoral pain and healthy individuals

Abstract

Understanding of the exact cause of patellofemoral pain has been limited by methodological challenges to evaluate in-vivo joint motion. This study compared six degree-of-freedom patellar motion during a dynamic lunge task between individuals with patellofemoral pain and healthy individuals. Knee joints of eight females with patellofemoral pain and ten healthy females were imaged using a CT scanner in supine lying position, then by a dual-orthogonal fluoroscope while they performed a lunge. To quantify patellar motion, the three-dimensional models of the knee bones, reconstructed from CT scans, were registered on the fluoroscopy images using the Fluomotion registration software. At full knee extension, the patella was in a significantly laterally tilted (PFP: 11.77° ± 7.58° vs. healthy: 0.86° ± 4.90°; p = 0.002) and superiorly shifted (PFP: 17.49 ± 8.44 mm vs. healthy: 9.47 ± 6.16 mm, p = 0. 033) position in the patellofemoral pain group compared with the healthy group. There were also significant differences between the groups for patellar tilt at 45°, 60°, and 75° of knee flexion, and for superior-inferior shift of the patella at 30° flexion (p ≤ 0.031). In the non-weight-bearing knee extended position, the patella was in a significantly laterally tilted position in the patellofemoral pain group (7.44° ± 6.53°) compared with the healthy group (0.71° ± 4.99°). These findings suggest the critical role of passive and active patellar stabilizers as potential causative factors for patellar malalignment/maltracking. Future studies should investigate the associations between patellar kinematics with joint morphology, muscle activity, and tendon function in a same sample for a thorough understanding of the causes of patellofemoral pain. © 2018 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

The effect of patellofemoral pain syndrome on patellofemoral joint kinematics under upright weight-bearing conditions

“…The PT values of the control group remained relatively constant. Regarding the difference between the PT values of the PFP and control groups, our results are generally consistent with the trends in value change compared to the referenced study [19]. However, our values are different from the referenced study's values.…”

“…Esfandiarpour et al [19] also reported a difference in PR values between the PFP and control groups during NWB0˚and WB0˚of about 40˚, while in the present study, there was a difference in the cross-flexion angle of about 10˚between NWB0˚and WB0˚.…”

“…Some reports have provided measurements during unrealistic conditions, such as PFP evaluation in the supine position only [34] or while leaning on the equipment during the loading task [23]. For example, in a study by Esfandiarpour et al [19], the lunge test was performed with one leg supported on the ground, while the knee of the other leg was flexed at 90˚. The lunge, supine, and leaning tests differ from actual conditions that involve squatting or straightening to mimic movements performed in daily activities.…”

“…Carlson et al showed that a strongly contracted quadriceps reduce the bony constraint on the patella, causing the patella to deviate from normal tracking along the femoral groove [34]. Especially, in weight-bearing conditions, an activation imbalance of quadriceps causes the abnormal action of the patella in the PFP group [19]. Previous studies have speculated that the cause of the activation imbalance of quadriceps might be that the muscles in the PFP group adapted to reduce the concentrated joint stress and consequently reduce pain, increasing the area of patellofemoral contact [35,36].…”

Dynamic Evaluation of Patellofemoral Instability: A Clinical Reality or Just a Research Field? A Literature review

“…The processing time ranged from 48–177 min, a significant reduction compared to previous works. In 2018, a new trial was conducted comparing the PFJ biomechanics of patients with anterior knee pain and volunteers, by a computerized combination of static CT images and dynamic fluoroscopy.…”