I'll give you an example of what I mean by clinical decision. I work in a skilled nursing facility (SNF) and I work primarily with geriatric patients. Let's say a 95 y.o. patient is complaining of chronic back pain and I can easily see that she has a severe kyphosis in her thoracic spine where she says it hurts. My intuition tells me that her extreme posture is probably contributing to her pain and speculate that reducing this curvature would improve her symptoms. But then I may think back to my physiology text, and think about age related changes that occurs in connective tissues, how there is increased fibrosis, reduced water content, decrease in elastin, etc. which in turn causes changes in the tissue viscoelasticity, which means that connective tissues are less tolerant to tension and thus less pliable. The clinical significance of this is that this means that it will take more time and effort to correct this patient's posture to reduce pain, let alone the changes in the tissue also means that it will be harder for the patient to strengthen their muscles to reinforce a better posture and maintain it enough to prevent further back pain. In other words, correcting her posture may be an unrealistic goal in this scenario (also keep in mind that I would likely have a limited time frame in working with this patient due to her stay being influenced heavily by insurance reimbursement). Upon further examination of her posture, I may discover that her kyphotic spine is making her lean forward and is displacing her center of mass forward, and biomechanically speaking, this places more strain on the postural muscles of the back. I may then suggest using an assistive device (cane, walker), so that she can improve her balance by increasing her base of support, and reduce the strain on her back muscles by having her transfer some weight through her upper extremities to reduce the workload on the back.

Another example could be the significance of stages of tissue healing or nature/location of a fracture in understanding weight-bearing precautions. Fractures that are treated in particular ways may require a period of reduced weight-bearing to allow sufficient callus formation, mineralization, and remodelling to ensure that sufficient integrity of the bone has returned. Osteology tells us that particular parts/segments of bones play different roles in bearing load/tension, so this could also impact weight bearing after fractures. In a way, these are probably some of the things ortho's take into considerations when they are making their decisions.

Keep in mind that the academic side and the actual clinical practice in PT will differ, since a vast majority of your time and effort will be spent actually treating the patient, more about clinical application of your basic sciences and how to practically apply it.

It also depends on how you perceive physical therapy, just another job to make money or a career in health profession? You don't always have to think about the science behind things if you just want to make money as a PT, or you can actually take science and evidence into consideration in your work and try to become a better clinician and a more important role in an interdisciplinary team. You may want to become a clinician, educator, researcher, there are many positions you can take up with a DPT (or the DPT will help lay out a pathway to that), with each requiring varying degrees and application of your basic scientific knowledge.