My husband's patella tendon was torn during surgery for a total knee replacement. how will the recovery from the tendon injury effect tkr recovery?

It will definitely: prolong recovery to a degree as the patellar tendon is a significant part of knee stability and mobility.

Varies: With a good repair, it should go on to heal well. There are precautions to take to reduce the risk of it becoming a problem. Discuss these issues with your surgeon who has the best information about the actual situation and the repair technique and how he/she wants to manage it for best results.