An Intramedullary alignment rod is a surgical instrument placed inside the hollow center (“canal”) of a bone to help guide alignment. It is commonly used during knee surgery to position cutting guides and implants accurately. In the knee, it is most often associated with aligning the femur (thigh bone) during total knee replacement. It is typically a temporary tool used during the operation, not an implant meant to stay in the body.

A Laminar spreader is a handheld surgical instrument designed to gently separate (distract) tissues or bony surfaces. It uses two flat “blades” and a controlled spreading mechanism to create working space. It is commonly used in orthopedic surgery, including procedures around the knee, to improve exposure and help with alignment or reduction. It is a temporary tool used during an operation and is removed before the procedure ends.

A Spacer block is a tool or temporary implant used to create or measure space inside a joint. It is most commonly discussed in knee replacement surgery and revision knee surgery. It helps surgeons assess how the knee “gaps” open in extension and flexion. In some infection cases, a spacer may also be left in the knee temporarily between staged operations.

Trial components are temporary implant parts used during joint replacement surgery to test fit and function. They help the surgical team choose the final implant size and position before permanent parts are placed. They are most commonly used in knee replacement procedures, including total and partial knee arthroplasty.

Extension gap is the space and soft-tissue “tension window” in the knee when the knee is fully straight (in extension). It is most commonly discussed during total knee replacement (total knee arthroplasty, TKA) and complex knee reconstruction. Clinicians use it to describe how the femur and tibia relate after bone preparation and soft-tissue balancing. In plain terms, it helps the surgical team judge whether the straightened knee will feel stable, smooth, and appropriately tight.

Flexion gap is the space between the thigh bone (femur) and shin bone (tibia) when the knee is bent. It is most commonly discussed during total knee replacement and other knee reconstructive procedures. Clinicians use it to describe how “open” or “tight” the knee feels in bending and how stable it is. In simple terms, it helps surgeons match knee motion with knee stability.

Gap symmetry is a way of describing how evenly the knee “opens” on the inside and outside when it is straight and when it is bent. It is most commonly discussed during knee replacement surgery planning and technique. Clinicians use it to describe balance between the ligaments and the joint surfaces. In simple terms, it aims for a stable knee that does not feel too tight on one side or too loose on the other.

Soft tissue balancing is the process of adjusting the tension of ligaments and other soft tissues around a joint so the joint moves smoothly and remains stable. In the knee, it commonly refers to balancing the tissues during knee surgery, especially total knee replacement. It can also describe non-surgical efforts to reduce uneven forces around the knee through rehabilitation strategies. The overall goal is a knee that tracks, bends, and straightens in a controlled and comfortable way.

Ligament balancing is the process of adjusting soft-tissue tension around a joint so the joint moves smoothly and feels stable. In the knee, it usually refers to balancing the collateral ligaments and surrounding capsule so the femur and tibia track correctly. It is most commonly discussed during knee replacement surgery, but the concept also applies to other knee procedures and rehabilitation planning. The goal is not “tight” or “loose,” but an appropriate, even tension that matches the person’s anatomy and the procedure being done.

Joint line restoration means re-establishing the knee’s normal “joint line” height and position. The joint line is the level where the femur (thigh bone) and tibia (shin bone) meet and move against each other. Joint line restoration is most commonly discussed in complex knee surgery, especially revision total knee replacement. It is used to improve knee mechanics when the original joint line has shifted due to arthritis, injury, or prior surgery.