Which factors predict outcome in the nonoperative treatment of patellofemoral pain syndrome? A prospective follow-up study Kannus P, Nittymaki S. Med. Sci. Sports Exerc. 1994; 26(3):

Was a defined, representative sample of patients assembled at a common point in the course of their disease?---Y 22 men, 27 women; 27± 9 y/o. 17- competitive athlete; 32- recreational athlete All have a characteristic history and symptom of the PFPS for one knee at least 2 months ’ duration.

Was patient follow-up sufficiently long and complete?---Y Training for 6 weeks, the correct performance of the exercise was controlled at weekly follow-up. No follow-up of any kind was done between the 6-wks evaluation and that at 6 months( the final outcome assessment).

Were objective outcome criteria applied in a blind fashion?---Y Visual Analog Scale( VAS ) Lysholm knee scores Tegner functional knee scores

If subgroups with different prognosis are identified, was there adjustment for important prognostic factors?---N All subjects served as a group and received the same treatment.

Was there validation in an independent group of patients?---N 49 patients visiting the clinic due to a characteristic unilateral PFPS during a 3- yr period were accepted in the analysis.

How likely are the outcomes over time? Change scores compared to baseline measures (6-wks). 6-wk check point: age correlated to VAS (-0.41), Lysholm scores (-0.34), Tegner scores (-0.41). 6-months check point: age correlated to lysholm scores (-0.27), Tegner scores (-0.41).

How precise are the prognostic estimates? Age accounted for less than 20% for the variation seen in the outcome variables, as determined by the r 2 -value of the age.

Confidence interval around the measure of prognosis n= 49, p= 70% SE= √ 0.7 * 0.3 / 49= 0.065= 6.5% 95% CI= 70% ± 1.96 * 6.5% 57.3% ~ 82.7% PEDro