LILLIAN'S CASE
INTERACTIVE CASE #4
Case Introduction
Lillian is a 21-year-old college student who twisted her knee while running two days ago and is now in severe pain with knee swelling.
KNEE PAIN
WHAT DOES AN MRI SHOW?
ANATOMY OF THE KNEE
Lillian's knee is swollen and painful. She cannot walk or bend it easily, and the swelling hasn't improved in two days. She decides to see the doctor.
Orthopedic Surgeon
STEP ONE
Initial Visit
Why is the ACL important and what happens when it tears?
The anterior cruciate ligament (ACL) is one of the major stabilizing ligaments of the knee, connecting the femur (thigh bone) to the tibia (shin bone). Its primary role is to prevent the tibia from sliding forward and to control rotational movement of the knee during activities such as cutting, pivoting, and jumping. When the ACL tears, usually during sudden changes in direction or awkward landings, the knee can become unstable, leading to symptoms such as a popping sensation, rapid swelling, pain, and difficulty bearing weight. Because the ACL has a limited blood supply, it does not heal well on its own. Untreated instability can increase the risk of secondary injuries, including meniscus tears and early osteoarthritis. Thus, evaluation by an orthopedic specialist is important, especially for active individuals like Lillian.
SOURCE: Johns Hopkins Medicine
SOURCE: Mayo Clinic
PART 2
Answer questions related to the video and receive a key that you can use to open the vault. Good luck!
MRI Technologist
STEP TWO
PART 1
Think about it:
How does an MRI machine work?
MRI (Magnetic Resonance Imaging) uses a powerful magnetic field and radiofrequency waves to produce detailed images of the body's soft tissues without exposing patients to ionizing radiation. The machine itself is shaped like a large donut because the opening houses a superconducting magnet that surrounds the patient, creating a uniform magnetic field. When the patient enters the scanner, hydrogen atoms in the body's water molecules align with the magnetic field. Radiofrequency pulses temporarily disrupt this alignment, and as the atoms return to their original positions, they emit signals detected by the MRI scanner. A computer processes these signals into detailed cross-sectional images, allowing physicians to examine ligaments, cartilage, muscles, and other soft tissues (National Institute of Biomedical imaging and Bioengineering, 2025). In Lilian's case, an MRI provides a very useful visualization of the knee's internal structures.
PART 2
Answer questions related to the video and receive a key that you can use to open the vault. Good luck!
Orthopedic Surgeon
STEP THREE
Visit after MRI
What is ACL Reconstruction Surgery and When is it Necessary?
When an ACL tears, the patient and surgeon can choose between non-surgical treatment (physical therapy or bracing) or surgery. Surgery is typically recommended for young, active patients or those with significant knee instability. During ACL reconstruction surgery, the orthopedic surgeon takes a tendon graft, most commonly from the patellar tendon or hamstring of the patient’s own body (autograft) or from cadaver tissue (allograft), and uses it to replace the torn ACL. The graft is threaded through tunnels drilled into the femur and tibia to the position of the original ACL, where it is anchored in place using screws or other fixation devices, thereby reconstructing the ligament. This procedure is performed arthroscopically, meaning it is minimally invasive with only one or two small incisions. Following surgery, recovery typically spans 6 to 12 months of physical therapy focused on restoring strength, range of motion, and neuromuscular control.
SOURCE: Johns Hopkins Medicine
PART 2
Answer questions related to the video and receive a key that you can use to open the vault. Good luck!
Physical Therapist
STEP FOUR
PART 1
Think about it:
Bones vs. Muscles vs. Tendons vs. Ligaments
The musculoskeletal system works because each structure has a distinct role. Bones provide the rigid framework of the body and form joints where movement can occur. Muscles generate the force that produces movement by contracting and relaxing. Tendons are strong, fibrous tissues that connect muscles to bones, transmitting the force of muscle contraction to move the skeleton. Ligaments, in contrast, connect bone to bone and primarily function to stabilize joints and limit excessive motion. Injuries such as ACL tears occur when ligaments are stretched beyond their capacity, leading to joint instability even if the surrounding muscles and bones remain intact. Understanding how these tissues work together helps explain why rehabilitation after knee injuries focuses not only on the damaged ligament but also on strengthening the supporting muscles around the joint.
PART 2
Answer questions related to the video and receive a key that you can use to open the vault. Good luck!
Orthopedic Surgeon
STEP FIVE
Final Visit: Lillian's Successful Treatment!
Although Lillian's case was successful,
there can be complications
Although ACL reconstruction has reported satisfactory outcomes in approximately 75% to 97% of patients, some individuals may experience graft failure following the procedure. A graft is a piece of tissue, often taken from the patient's own patellar tendon, hamstring tendon, or a donor, that is used to replace the torn ACL. Common causes of ACL reconstruction failure include recurrent instability, pain, stiffness, infection, improper graft placement, failure of graft incorporation, and complications related to rehabilitation. In some cases, patients may require revision surgery to restore knee function and stability. Despite these potential complications, ACL reconstruction remains an effective treatment option for many individuals with ACL injuries and can help restore knee stability and function when combined with appropriate rehabilitation (Samitier et al., 2015).
