What procedure was performed on the patient with a preoperative diagnosis of a cyst on the knee?

The procedure performed on a patient with a preoperative diagnosis of a cyst on the knee is the excision of a Baker's cyst. A Baker's cyst, also known as a popliteal cyst, is a fluid-filled sac that forms in the popliteal space, located behind the knee. It is often associated with joint conditions such as arthritis or cartilage tears, which can lead to an accumulation of synovial fluid.

Excision is the appropriate procedure to remove this cyst, especially if it causes discomfort or limits the patient's mobility. During the excision, the surgeon would carefully remove the cyst while preserving surrounding tissues and ensuring that the cyst is completely removed to prevent recurrence. This procedure is typically done through a small incision and can often be performed arthroscopically, but the focus remains on excising the cyst itself.

The other options listed are not relevant to treatment for a cyst located at the knee. For instance, arthroscopy might involve viewing or treating joint issues, but it does not specifically address cyst removal. Partial nephrectomy and radical prostatectomy are unrelated surgical procedures performed on the kidneys and prostate, respectively, and do not pertain to a knee cyst diagnosis.