A 45-year-old has a dislocated patella in the left knee after a car accident. She taken to the hospital by EMS for surgical treatment. In the surgery…

The procedure described is an open treatment for a patellar dislocation, as indicated by the surgical incision. The documentation explicitly states, "the entire patella is freed and removed," which constitutes a total patellectomy. CPT® code 27566 is the correct code as it describes an open treatment of a patellar dislocation, which may include a partial or total patellectomy. The modifier -LT is appended to indicate the procedure was performed on the left knee.

A. 27562-LT: This code is for a closed treatment of a patellar dislocation. The procedure described involved an incision, making it an open treatment.

B. 27552-LT: This code is for a closed treatment of a knee (tibiofemoral) dislocation, not an open treatment of a patellar dislocation.

C. 27556-LT: This code is for an open treatment of a knee (tibiofemoral) dislocation, which is anatomically different from the patellar dislocation described.

1. American Medical Association. (2022). CPT® 2023 Professional Edition.

Section: Musculoskeletal System

Femur (Thigh Region) and Knee Joint

Manipulation.

Page/Code: 27566. The code descriptor states: "Open treatment of patellar dislocation

with or without partial or total patellectomy." This directly matches the procedure performed.

Page/Code: 27562. The descriptor specifies "Closed treatment of patellar dislocation; requiring anesthesia

" which is incorrect as the procedure was open.

Page/Code: 27556. The descriptor specifies "Open treatment of knee dislocation

" which is incorrect as the dislocation involved the patella

not the main knee joint.

2. AAPC. (2022). CPC Official Study Guide. Chapter 11: Musculoskeletal System.

The section on the knee joint distinguishes between codes for tibiofemoral joint dislocations (knee dislocations) and patellar dislocations. It clarifies that open procedures require direct visualization through an incision

while closed procedures do not. The guide instructs coders to select 27566 for open repair of a patellar dislocation

especially when a patellectomy is performed concurrently.