Factors associated with patellofemoral pain syndrome: a systematic review

This review systematically summarises factors associated with patellofemoral pain syndrome (PFPS). A systematic literature search was conducted. Studies including ≥20 patients with PFPS that examined ≥1 possible factor associated with PFPS were included. A meta-analysis was performed, clinical heterogeneous data were analysed descriptively. The 47 included studies examined 523 variables, eight were pooled. Pooled data showed a larger Q-angle, sulcus angle and patellar tilt angle (weighted mean differences (WMD) 2.08; 95% CI 0.64, 3.63 and 1.66; 95% CI 0.44, 2.77 and 4.34; 95% CI 1.16 to 7.52, respectively), less hip abduction strength, lower knee extension peak torque and less hip external rotation strength (WMD -3.30; 95% CI -5.60, -1.00 and -37.47; 95% CI -71.75, -3.20 and -1.43; 95% CI -2.71 to -0.16, respectively) in PFPS patients compared to controls. Foot arch height index and congruence angle were not associated with PFPS. Six out of eight pooled variables are associated with PFPS, other factors associated with PFPS were based on single studies. Further research is required.