While patients have the right to refuse any type of medical care, it is important to understand the consequences; in your case, when you prematurely end physical therapy. The most obvious consequence is not returning to your highest level of activity and performance.
Let's review what you need to know about the anterior cruciate ligament (ACL) and the stability of your knee joint. One of the roles of the ACL is to provide feedback to the brain regarding the knee joint's position, e.g. the knee is bent or the knee is straight.When the ACL is injured you lose this sensory ability, often causing people to walk on a bent knee at times when it should be straight. This type of walking places increased stress and strain on the structures surrounding the knee and minimizes your ability to effectively contract your thigh muscles (quadriceps and hamstrings). This combination of bad biomechanics increases your risk of reinjuring the ACL. If you are prematurely leaving physical therapy after ACL repair/surgery, there is even a greater risk of reinjury, due to the normal impact of invasive surgery on your joint structures and mobility, muscle performance, and overall motor control.
It is important to discuss your intentions with your physical therapist so that you are fully informed on the associated risks, if any. This is a great time to make sure that you both are working towards the same outcome - your goals. Finally if you are considering ending your physical therapy prematurely due to financial, scheduling, or other personal issues, talk to your therapist who may be able to offer you other options that you hadn't considered like less frequent appointments or a payment plan. Your physical therapist wants to help you to succeed, so don't hesitate to talk to him/her about anything that is impacting your progress.