1. Pathology & Biomechanics of Unicompartmental Arthritis John Goodfellow Nuffield Orthopaedic Centre, Oxford

2. Extreme case

3. Typical cases Antero-medial OA Functionally intact ACL Posterior Anterior

4. Preserved Cartilage Lost Cartilage & Bone Antero-medial OA

5. Preserved Cartilage Lost Cartilage & Bone Antero-medial OA Varus deformity corrects in flexion Medial collateral ligament tight Prevents ligament shortening Loss of cartilage & bone Varus deformity Medial collateral ligament lax

6. Antero-medial OA Varus deformity corrects in flexion Medial collateral ligament tight Prevents ligament shortening Correctable Varus Deformity

7. ACL Intact ACL rupture Loss of cartilage & bone Posteriorly Medial collateral ligament lax Varus deformity persists in flexion Medial collateral ligament lax MCL short Fixed deformity

8. Extreme case

10. Deformity corrects in flexion Bone preserved posteriorly

11. Deformity corrects with stress

12. Anteromedial Osteoarthritis Cartilage loss limited to ANTERIOR TIBIAL PLATEAU INFERIOR FEMORAL CONDYLE ACL INTACT CORRECTABLE VARUS DEFORMITY

13. Varus Valgus

14. Lateral X-ray ANTERIORANTERIOR Posterior extent of cartilage loss correlates with the state of the ACL ACL+ ACL- Gross (sublux) ACL?

15. Anteromedial Osteoarthritis

16. Thank you