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): 289-296.

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 r2-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