Table 1.

Update on studies for patellofemoral pain syndrome (PFPS) tests

Test	Reliability & validity	Comments	Source
Q angle	“Standard Q angle”: mean of 14.8° with 95% CI) of ±5.4° for all, mean of 13.5° with 95% CI of ±5.2° for men, mean of 15.9° with 95% CI of ±4.8° for women. No significant difference between right and left knees of males or females. 2.4° difference between male and female means found to be due to the average height difference	30 men and 27 women without history of knee problems or family history of patellar dislocations. Both knees were measured on each subject	Merchant et al. [20]
Patellar tilt	Patellar tilt (LR+ = 5.4 and LR- = 0.6) to diagnose PFPS	Meta-analysis. 5 studies met criteria (one study had high methodological quality, two studies had good methodological quality, and two studies had low methodological quality)	Nunes et al. [21]
Crepitus	Crepitus was more common in women with PFPS (50.7%) compared to those without (33.3%) (Χ2 = 4.17; p = 0.031)	65 women with PFPS and 51 pain-free women in study	de Oliveira Silva et al. [22]
Strength testing	The PFPS group had significant deficits compared to the control group in isometric strength (21-25%) for hip abduction (ES = 0.98) and extension (ES = 0.85)	16 with PFPS and 16 controls in study	Nunes et al. [23]
Functional testing	The PFPS group was 15% slower climbing stairs (ES = 0.90), performed 12% fewer chair stands (ES = 0.62), and forward hopped 20% shorter (ES = 0.79)	16 with PFPS and 16 controls in study	Nunes et al. [24]
Clustering	Cluster 1 showed sensitivity of 64% and specificity of 93% in diagnosing PFPS. Cluster 2 showed sensitivity of 56% and specificity of 96%	Study included 279 subjects, 75 of who had PFPS Cluster 1: < 40 yo and either isolated anterior knee pain or medial patellar facet tenderness Cluster 2: age 40–58 yo, isolated anterior or diffuse knee pain, mild to moderate difficulty descending stairs, medial patellar facet tenderness, and full passive knee extension	Decary et al. [1••]
VMO volume, insertion level, and fiber angle measured with US	All 3 measurements were significantly smaller in the PFPS group (p < .05). Multivariate analysis of variance has revealed a Wilks λ value of .845 and an F value of 5.640 (p = .001)	58 patients with PFPS included (31 with bilateral involvement ➔ 89 knees total)	Jan et al. [25]
Gluteus medius muscle thickness measured with US	15.9 ± 19.3% vs. 4.4 ± 21.9%, p < 0.05	PFPS patients (n=27) had significantly large left-right side imbalance in muscle thickness during activation	Payne et al. [26••]
Knees with PFP had a significantly higher prevalence of intra-articular effusion	p = .018	N = 67, with PFPS found in 54.5%. Population was young female dancers (7th graders)	Siev-Ner et al. [27]
Quadriceps and patellar tendon thickness measured with US	Quadriceps tendon thickness values of ≥ 0.54 cm were found to have 80% sensitivity and 71% specificity for PFPS diagnosis in the ROC curve analysis Patellar tendon thickness values of ≥0.35 cm were found to have 66.7% sensitivity and 67.7% specificity for PFPS diagnosis in the ROC curve analysis	n=61 (30 with PFPS, 31 controls) (28 men and 33 women; mean age: 30.79 ± 6.55 years)	Kizikaya et al. [28]

CI confidence interval, US ultrasound, VMO vastus medialis obliquus, ROC receiver operating characteristic, ES effect size