Patent ID: 11918491
Assignee: ZIMMER, INC.
Field: Medical technology (Instruments)
Classification: CPC A | IPC A

Claim 14:
15. A method, comprising:
placing a reference surface of a housing against a resected distal end of a femur of a knee joint, the housing being elongated along a longitudinal axis, the reference surface defining a plane that includes the longitudinal axis, the reference surface further defining a flexion/extension axis as being parallel to the plane and perpendicular to the longitudinal axis;
setting a reference orientation of a housing against the resected distal end of the femur by depressing a zero button located on the housing, the housing including a rotation sensor configured to measure a flexion/extension position of the housing, the flexion/extension position being a relative rotational position about the flexion/extension axis with respect to the reference orientation, the housing including a flexion/extension display located on the housing and configured to visually represent the measured flexion/extension position;
positioning the knee joint at a first orientation;
determining, from the rotation sensor and the flexion/extension display, that the knee joint in the first orientation has a first flexion/extension value that is within a first specified range of flexion/extension values, the housing including a force sensor configured to measure a force exerted between opposing surfaces of the housing at a distal portion of the housing, the housing including a force display located on the housing and configured to visually represent the measured force;
removably attaching a first shim, having a first thickness, to the distal portion of the housing over one of the opposing surfaces, such that the force sensor measures a force exerted between the first shim and the other of the opposing surfaces;
inserting the first shim and the distal portion of the housing into the knee joint, with the knee joint in the first orientation, to seat the housing and the first shim in the knee joint;
measuring, with the force sensor and the force display, a first force value obtained with the first shim and the distal portion of the housing seated in the knee joint and the knee joint in the first orientation;
determining that the first force value is within a specified range of force values;
positioning the knee joint at a second orientation different from the first orientation;
determining, from the rotation sensor and the flexion/extension display, that the knee joint in the second orientation has a second flexion/extension value that is within a second specified range of flexion/extension values;
inserting the first shim and the distal portion of the housing into the knee joint, with the knee joint in the second orientation, to seat the housing and the first shim in the knee joint;
measuring, with the force sensor and the force display, a second force value obtained with the first shim and the distal portion of the housing seated in the knee joint and the knee joint in the second orientation;
determining that the second force value is within a specified range of force values; and
selecting an implant having a size that corresponds to the first thickness.