Vague Posterior Knee Discomfort in a Soccer Player: A Clinical Vignette

A 24-yr-old male soccer player presented with a 7-yr history of left posterior knee "looseness." Evaluation 7 yrs ago, at the time of initial injury, revealed atraumatic anterior and posterior cruciate ligament sprains. On representation, the patient described the pain as a constant, dull ache, 3/10, but his biggest complaint was this feeling of "instability" and looseness where his knee would "buckle" 3-4 times a week. Physical examination was positive for grade 1 posterior drawer and grade 1 posterior sag signs. Reverse KT-1000 testing showed a 3-mm side-to-side difference. Sonographic evaluation confirmed magnetic resonance imaging findings of posterior cruciate ligament laxity and buckling and a small cystic lesion abutting the posteromedial margin of the distal 1/3 of the posterior cruciate ligament. After a trial of physical therapy, the patient elected to undergo experimental injection of dextrose hyperosmolar solution. This resulted in resolution of the cyst and reverse KT-1000 measurements improved to a side-to-side difference of 1 mm. The patient's subjective feeling of looseness and instability resolved by 7 wks.