Which of the following self-retaining retractors would be used during total hip arthroplasty?

The Charnley retractor is specifically designed for use during total hip arthroplasty due to its ability to provide adequate exposure of the surgical field, especially around the hip joint. This type of retractor features a design that allows it to hold soft tissues and structures away from the surgical site, which is crucial for maintaining visibility and access during the intricate procedures involved in hip replacement surgery.

In total hip arthroplasty, it's essential to ensure that the area being worked on is fully accessible without obstructing critical anatomical structures. The Charnley retractor's shape and mechanism allow it to achieve this effectively, making it a preferred choice among surgeons.

The other retractors listed—Balfour, Richards, and Weitlaner—serve different purposes and regions in surgery. The Balfour retractor is primarily used for abdominal surgeries, the Richards is often employed in orthopedic procedures other than hip arthroplasties, and the Weitlaner retractor is typically used for superficial or less invasive surgeries where broad exposure is needed but may not offer the same specialized use in hip surgeries as the Charnley retractor does.