Assembly for use in knee surgery

An assembly for use in knee surgery, which comprises:

• a. a patella sensor component comprising:
• i. a backing plate which can be fitted to a patella and which has at least one sensor which can generate a signal corresponding to a compressive load applied to the backing plate,
• ii. at least first and second shims which provide a patella bearing surface for articulation against a surface on a patient's femur, and which can be positioned individually or in one or more combinations on the backing plate so as to face the patient's femur, the combinations defining first and second positions of the bearing surface relative to the patella,
• b. a cutting instrument having a cutting head for cutting the patella on a selected resection plane,
• c. a clamp for a patella having opposing jaws which can be moved towards one another to clamp the patella between them, the clamp providing:
• i. a reference surface for engaging a posterior surface of the patella,
• ii. a support surface for supporting the cutting head of the cutting instrument, thereby locating the cutting instrument relative to the clamp,
• d. at least first and second locator inserts which can be mounted individually or in one or more combinations on or relative to the clamp, providing a physical connection between the reference and support surfaces which define first and second positions of the support surface relative to the reference surface, and thereby define first and second positions for the resection plane relative to the posterior surface of the patella,
• in which an increment between the first and second positions of the bearing surface defined by the combinations of the first and second shims relative to the patella matches the increment between the first and second positions of the support surface relative to the reference surface.