Orthopaedic cutting instrumentation with cam locking arrangement

A knee cutting instrument comprising:

• a) an alignment rod having rod end portions and a linear axis that can be used by a surgeon to define alignment with a patient's long bone;
• b) a knee cutting instrument guide that slides upon the alignment rod between the rod end portions;
• c) said guide including a locking member that forms a connection with the rod at a selected position along the rod, the locking member including a cam member that rotates about a pivot on the cutting instrument, said cam member having a body with an arm for enabling a user to move the cam member and a locking portion with a bearing surface that engages the rod, said locking portion of the locking member having a curved slot that extends about the pivot in between the pivot and the periphery of the locking member;
• and
• d) the curved slot having a closed end portion and a variable radius of curvature.

An orthopaedic instrument comprising:

• a) a pair of orthopaedic instruments, a first of said instruments having a locking member;
• b) wherein the first instrument is movable along a second of the instruments into different positions;
• c) wherein the locking member secures the pair of instruments together in a selected position of one instrument relative to the other instrument;
• d) the locking member including a cam member that rotates about a pivot on the first instrument, said cam member having a body with an arm that enables a user to rotate the cam between engaged and disengaged positions;
• e) the locking member having a locking portion with a periphery that includes a bearing surface that engages the second instrument;
• f) a slot that extends generally about the pivot and generally in between the pivot and periphery of the locking member;
• g) said slot having a closed end portion;
• and
• h) wherein when the locking member is engaged, the bearing surface is in contact with the second instrument.

An orthopaedic instrument comprising:

• a) a pair of orthopaedic instruments, a first of said instruments having a locking member;
• b) wherein the first instrument is movable along a second of the instruments into different positions;
• c) wherein the locking member secures the pair of instruments together in a selected position of one instrument relative to the other instrument;
• d) the locking member including a cam member that rotates about a pivot on the first instrument, said cam member having a body with an arm that enables a user to rotate the cam between engaged and disengaged positions;
• e) the locking member having a locking portion with a periphery that includes a bearing surface that engages the second instrument;
• f) a slot that extends generally about the pivot and generally in between the pivot and periphery of the locking member;
• g) said slot having a closed end portion;
• h) wherein when the locking member is engaged, the bearing surface is in contact with the second instrument;
• and
• i) wherein the locking member includes means for enabling the locking member to surpass a critical peak force at a selected point of travel along its range of motion in between disengaged and the engaged positions, and once the selected point of travel is reached, an applied force prevents further travel of the locking member.

An orthopaedic instrument comprising:

• a) a pair of orthopaedic instruments, a first of said instruments having a locking member;
• b) wherein the first instrument is movable along a second of the instruments into different positions;
• c) wherein the locking member secures the pair of instruments together in a selected position of one instrument relative to the other instrument;
• d) the locking member including a cam member that rotates about a pivot on the first instrument, said cam member having a body with an arm that enables a user to rotate the cam between engaged and disengaged positions;
• e) the locking member having a locking portion with a periphery that includes a bearing surface that engages the second instrument;
• f) a slot that extends generally about the pivot and generally in between the pivot and periphery of the locking member;
• g) said slot having a closed end portion;
• h) wherein when the locking member is engaged, the bearing surface is in contact with the second instrument;
• and
• i) wherein said slot allows deflection of a portion of the locking member upon actuation of the locking member to the engaged position until a peak deflection is surpassed, and wherein any additional deflection applies to a force preventing further cam motion beyond the engaged position.