Adjustable tibial osteotomy jig and method

An adjustable tibial osteotomy jig, comprising:

• a. a goniometer, the goniometer further comprising:
• (1) first and second arms, each arm having a base;
• (2) a pivot movably connecting the arms at their bases;
• the pivot having a bore therethrough;
• (3) a locking device for locking the arms of the goniometer in a predetermined angular relationship;
• and,
• (4) a scale for angular measurement of the relative positions of the arms;
• b. a proximal cutting guide, slidably mounted on the first arm;
• c. a distal cutting guide, slidably mounted on the second arm;
• d. each of the cutting guides having a transverse slot extending therethrough to define a cutting surface, and one or more holes extending therethrough;
• e. a clamp connected to each cutting guide for locking each cutting guide in a predetermined radial position along its respective arm;
• f. one or more pins passing through the holes in the proximal cutting guide and into a tibia, for fixing the proximal cutting guide in a first predetermined position with respect to the tibia;
• and,
• g. one or more pins passing through the holes in the distal cutting guide for fixing the distal cutting guide in a second predetermined position with respect to the tibia.

A method of performing a tibial osteotomy, comprising the steps of:

• a. providing a an adjustable tibial osteotomy jig, the jig comprising:
• (1) a goniometer, the goniometer further comprising:
• (i) first and second arms;
• (ii) a pivot movably connecting the arms;
• the pivot having a bore therethrough;
• (iii) a locking device for locking the arms in a pre-determined angular relationship;
• (2). a proximal cutting guide, slidably mounted on the first arm;
• (3) a distal cutting guide, slidably mounted on the second arm;
• (4) each of the cutting guides having a transverse slot extending therethrough to define a cutting surface, and one or more holes extending therethrough;
• and,
• (5) a clamp connected to each cutting guide for locking each cutting guide in a predetermined radial position along its respective arm;
• b. calculating a correction angle appropriate to the osteotomy and determining the lateral line for the transverse osteotomy cut;
• c. placing the proximal cutting guide against the tibia in a predetermined position below the lateral line;
• d. fixing the proximal cutting guide in the predetermined position by passing one or more guide pins through the holes in the proximal cutting guide and into the tibia;
• e. extending a saw blade through the transverse slot of the proximal cutting guide and making a transverse cut through the tibia to a distance less than the depth of the tibia;
• f. attaching the first arm of the goniometer through the clamp of the proximal cutting guide and locking the first arm into a predetermined position with the clamp;
• g. fixing the goniometer to the tibia in the predetermined position by inserting a fixation pin through the bore and into the tibia;
• h. adjusting the relative angle of the goniometer arms to the calculated correction angle by adjusting the second arm of the goniometer;
• i. locking the goniometer arms to maintain the calculated correction angle;
• j. placing the distal cutting guide onto the second arm of the goniometer by passing the clamp of the distal cutting guide over the second arm to a position near the tibia;
• k. locking the distal cutting guide onto the second arm;
• j. fixing the distal cutting guide in the predetermined position just obtained by passing one or more guide pins through the holes in the distal cutting guide and into the tibia;
• k. extending a saw blade through the transverse slot of the distal cutting guide and making an oblique cut through the tibia to a distance less than the depth of the tibia, and meeting the transverse cut;
• l. removing a wedge-shaped portion of the tibia formed by the transverse and oblique cuts through the tibia to form a void in the tibia;
• the void being defined by an upper side, created by the transverse cut, and a lower side, created by the oblique cut;
• and,
• m. drawing the upper and lower sides of the tibia together and permanently closing the void.