Blood Flow Restriction Training After Patellar INStability

This research study is designed to allow health care professionals and researchers to answer many questions about whether a new type of physical therapy called blood flow restriction training (called BFRT) will improve recovery for those with patellar instability.

Inclusion Criteria: * Diagnosis of traumatic patellar instability (either primary or recurrent) determined by an American Board of Family Medicine certified physician with a Certificate of Added Qualifications in Sports Medicine or licensed Physical Therapist utilizing clinical examination, radiographic imaging, and patients' reports of instability * Age 14 to 40 years * Skeletally mature with closed growth plates visualized by radiograph * A score of 80 or more on the Sports Activity Scale, which corresponds to participating in "running, twisting, turning (tennis, racquetball, handball, ice hockey, field hockey, skiing, wrestling)" at least 1-3 times per week * Desire to resume pre-injury activity level Exclusion Criteria: * Concomitant osteochondral lesion requiring surgical fixation * Radiographic evidence of osteoarthritis (\< Kellgren-Lawrence Grade 2) * Previous ipsilateral or contralateral knee surgery * Most recent instability event more than 3 months before enrollment * History of any inflammatory disorder * BMI \> 35 kg/m2 * Diabetes or uncontrolled hypertension * Varicose veins or a history of personal or immediate family history (parental or sibling) of deep vein thrombosis * Pre-existing conditions or previous surgeries that effect the ability to walk * Planned trips or vacations that will result in the inability to attend 4 consecutive physical therapy sessions