Verification of the presence of a subgroup classification of Patellofemoral pain patients in Turkish population

Background: Optimising patient outcomes in PFP by matching interventions to patient characteristics requires robust identification of patient subgroups. The TIPPS study identified three subgroups of PFP patients (named strong, weak and tight and weak and pronated) in a United Kingdom population using low-cost clinical tests that can be easily used in routine therapy practice.
Objective: To verify the TIPPS subgroup classification of patellofemoral pain (PFP) patients in another population.
Methods: A dataset from an intervention study undertaken in a Turkish population, which assessed PFP patients at their first visit using the same clinical tests and eligibility criteria as the TIPPS study, was analysed to explore the presence of subgroups using hierarchical cluster (HCA) analysis and latent profile analysis (LPA). The findings were compared with those of the original TIPPS dataset.
Results: Data from 85 participants was available. Nearly three-quarters (74%) were female and the mean age was 26 (SD 6.6) years. HCA and LPA confirmed three distinct PFP subgroups, which mapped onto the previously identified TIPS subgroups. However mean scores for the tests and frequency of the groups differed in the two populations.
Conclusion: This study verified the presence of the three PFP subgroups of strong, weak and pronated and weak and tight. Test scores differed between the Turkey and TIPPS datasets. Further research is warranted on ethnic differences in PFP factors and on the patient benefits of matching interventions to patient subgroups.