Fielden, who moved to the Falcons from Bedford Blues in 2010, had to be helped off the pitch 20 minutes in to the 43-0 win over Petrarca Padova in the Challenge Cup.
However the injury is not as bad as was first feared, with the 25-year-old targeting a speedy return.
Fielden, who has scored seven tries in 26 appearances for Newcastle, wrote on Twitter: "Good news only dislocated knee cap so will be back playing before the end of the season!"
Fielden is in his second spell at the club, having played for the academy during his time as a student in Newcastle.
However having helped the Falcons to the Middlesex Sevens crown in 2007, he went on to play for Cambridge before moving to the Blues in the RFU Championship.
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The entire All Blacks apparel line has been updated for 2013/14. Check out the New Zealand All Blacks polo.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Gilbert Blitz 8S rugby cleat is a great cleat at a great price of $69.99. Get a new pair of cleats today.
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The All Blacks Performance t-shirt is black with hints of blue from the training jersey. Very Cool.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.