The difference in a clinical measure of patella lateral position between individuals with patellofemoral pain and matched controls

Cross-sectional matched-pairs design. To investigate if differences existed in the medio-lateral position of the patella between subjects with patellofemoral pain (PFP) and matched controls. The assessment of patella position is often proposed as an essential aspect of clinical examination of individuals with PFP. To date, only 1 clinical method of assessing lateral patella position has been intensively investigated. Although there is a growing body of evidence on the reliability and validity of this method, no studies have investigated differences in patella position between patients with PFP and controls. Twelve female patients with PFP and 12 matched controls (mean +/- SD age, 21.9 +/- 2.6) had their medio-lateral patella position assessed in 20 masculine of flexion. Differences between groups were investigated with independent-groups t tests. All subjects were found to have a laterally located patella. The mean +/- SD lateral position for the individuals in the PFP group was 7.5 +/- 2.6 mm compared to 3.8 +/- 2.4 mm for the control group. This difference was statistically significant (P = .019). Intratester reliability of the measurement of patellar position, calculated using intraclass correlation model 3,1, was 0.86. Using this method of assessing patella position, the patella of individuals with PFP was significantly more laterally located than the patella of those in a matched control group.