Development of an Instrument for Measuring Patellar Mobility and Its Clinical Application

Chaired by the academic adviser of each presenter P h y s i c a T h e r a p y l Introduction Passive patellar mobility was believed to be one of the important forms of assessment for patient with patellofemoral pain (PFP) and the decreased range of motion (ROM) at the knee joint. Moreover, it shows the laxity of the knee joint which could also contribute to sports knee injuries. However, there is no methods to assess the quantitative measurment of patellar mobility in clinical situation. Given the need for objective measurements of patellofemoral (PF) joint impairments, we have developed a clinical device (patellofemoral joint arthrometer [PFA]) to quantify medio-lateral patellar displacement. The purposes of this research were 1) to assess the validy of prototype PFA, 2) to apply PFA to the person with PF and to compare with the healthy subjects, 3) to investigate the relationship of patellar mobility and knee ROM after total knee arthroplasty (TKA). Subjects: A total of 26 individuals (24 females and 2 males) participated, and 14 were asymptomatic with PFP. The average ± SD age, height and body mass of the participants was 27 ± 4 years, 164 ± 5 cm, and 59 ± 8 kg, respectively. Twelve of the participants had a current history of patellofemoral pain at the time of testing, while 14 were asymptomatic. Methods: A custom designed prototype PFA was used to assess the amount of lateral patellar displacement. PFA was secured to the femoral condyle, and the femur was refer to this measurement. The adjustable arm allowed the medial border of the patella to be localized in the frontal plane with respect to the fixed ruler. Subjects were measure the displacement of lateral patella between quadriceps relaxed and isometirc contracted by PFA. Following assessment of lateral patellar displacement using the PFA, participants underwent MRI of the patellofemoral joint. The same procedures of using PFA was performed on using MRI. Bisect offset index and patellar tilet angle was measured the true lateral patellar displacment. The comparion of these patellar mobilities using both methods was performed as the validity study. Subjects: The study comprised 22 females with PFP (PFP group) and 22 females who had no knee pain (control group) who were matched to the subjects with PFP based on age, height, and body mass index. Mehtods: Patellar mobility was measured objectively using PFA. Measurements of lateral and medial …