How is the front-wheel doing?
...totally missed that knee-thing. Hope you'll get fully recovered. Do not understand the diagnosis they gave you... a pulled patellar tendon means a draw-box(?) (lig. cruciforme(?)) injury with residing knee-instability. It almost always is associated with an initial swelling of the bursae... Or did you only get hit hard on the tendon just below (distal of) the patella? Damages to the cartilage of the joint? Hip? Pelvic/lumbar area? If knee is knocked backwards that hard, it will affect the hip-joint, pevic and lubar areas as well... fibula?
Avoid getting hit by objects, especilly large once like cars! It can get so darn unconfortable with way too much nociceptic activity
Large pannierns, and a sizeable fairing, are helpfull extras! Saved my left leg back in 1989
Making the bike apear larger helps getting car-drivers attension