Soft tissue structures around the knee are very complex. They are woven together and work to help one another stabilize, support, and move the joint. The way in which they share the load makes an injury of one ligament likely to affect the function of others as well.
Sometimes where one ligament ends and another begins is impossible to tell. Likewise, many of the ligaments are attached to the joint capsule surrounding the joint (or to the joint itself) in very unique ways. Connective tissue called fascia is also part of the soft tissue structures that helps hold everything together.
Some injuries are more obvious than others. For example, clinical tests performed by the physician are usually pretty clear if either one of the two main ligaments that criss-cross inside the joint are injured (posterior cruciate ligament or anterior cruciate ligament).
Damage to the corners can be much more difficult to diagnose. You might not realize it, but the knee actually has “corners.” There are two corners in the front (anterior) and two in the back (posterior.
Then add one a direction from each side: medial (side closest to the other knee) and lateral (side away from the other knee). Combining front and side and back and side gives us corners named anteromedial, anterolateral, posteromedial, and posterolateral.
Each “corner” is made up of the ligaments, meniscus (knee cartilage), tendons, and connective tissue that converge at that point. For example, the posteromedial corner (PMC) of the knee contains the posterior oblique ligament (POL), part of the hamstring muscle/tendon, the oblique popliteal ligament (OPL), and the back curved corner of the meniscus.
Traumatic force from an injury strong enough to tear one ligament is often enough to rip adjoining soft tissues. Identifying all areas of damage and injury can be difficult. Even with all or our imaging technology, the exact nature and extent of soft tissue and/or bone injury just isn’t clear. There can be subtle bone bruising, tiny bone fractures, or a pulling away of the meniscus from the edge of the bone.
Sometimes, it isn’t until the patient has gone through rehab and even a first surgery before the unrecognized damage becomes obvious enough to diagnose and treat. The delay isn’t always a disadvantage.
Some tissues heal on their own with enough time on their side. And in some cases, further testing is required to get to the bottom of the problem. That may take some time and patience.