Do the same minimum value requirements apply to chi-square for trend, as chi square?

Hi, I'm doing a project about dilated kidneys, these can be arranged into mild, moderate and severe. There are 53 patients in total.
I want to see if there is a trend in the severity of dilatation between those that have an 'adverse outcome' (like surgery, scarring etc) and those who do not.

Here is my data:
-----------------------mild(1) --- mod(2) ----severe(3)----Total
Adverse outcome------0------------4-----------5------------ 9
No adverse outcome--28-----------10--------- 6 ----------- 44
Total--------------------28----------14----------11----------- 53

Now, i realise these numbers are fairly small. I am new to statistics and initially tried a chi-square test for linear trend using software which came out as P=0.0003. however on reflection, the data values in some of the boxes are very low - do the same minimum values apply for chi-square for linear trend as with pearsons chi-square? ie 80% expected values should be above or equal to 5.

if i cannot use this test, please could you let me know of an alternative asap?
thanks a lot! :)