2. M.N.Tahmasebi,MD,RCSC, Professor of Knee Surgery TUMS Shariati Hospital Isfahan,1394 Pre-operative planning in UKA and the role of Patella

3. New era in Arthroplasty The more The knee surgeons do UKA The less complications are reported.(JBJS 2015) The more The knee surgeons do UKA The less complications are reported.(JBJS 2015)

4. Definition Unicompartmental knee arthroplasty: Prosthetic replacement of one compartment of the tibio-femoral joint, either medial or lateral, addressing the primary or secondary osteoarthritic narrowing of the joint rim, with the purpose to regain the pristine alignment of the limb and painless motion

5. UKA May be suitable for 5-30% of TKA recipients  Arno et al, J arthroplasty 2011  Robertsson et al, Acta Orthop 2010  Willis-Owen et al, Knee2009  Murray et al, JBJS-B 1998  Fumes et al, JBJS-A 2007  Kosikene et al, Acta Orthop 2008

6. UKA Young Patient 92% survivorship at 11 years < 60 yo  Swienckowski et al, JBJS-A 2004 94% survivorship at 12 years < 65 yo  83.4% return to sporting activities  Felts et al, Ortho Traumatol surg res 2010

7. PREOP EVALUATION KEYS Three arms of the evaluation: History, physical examination, and imaging.

8. Preop evaluation: clinics kozinn and scott, JBJS 1989 kozinn and scott, JBJS 1989 - Age >60 y/o - Age >60 y/o -Weight <82kg(181 lb) -Low activity demand -No pain at rest (+pain at rest= inflammatory arthritis -flexion to 100. Any flexion contracture 5 degrees or less -<15 degrees of varus/valgus deformity correctable

9. Preop evaluation: clinics The ACL should be intact to physical examination(the anterior drawer test should be negative even if the ACL is absent on an MRI examination.

10. Preop evaluation: clinics Clinical examination: most important things  One finger test positive ✔

11. Oxford UKA ignore the age, activity level, presence of chondrocalcinosis, patellofemoral damage, preoperative site of pain, and obesity in these patients The indications and contraindications for UKA are design dependent and, for the Oxford UKA, virtually any patient with significant pain and bone-on-bone AMOA can undergo a UKA. In particular, one can ignore the age, activity level, presence of chondrocalcinosis, patellofemoral damage, preoperative site of pain, and obesity in these patients. If one uses the selection criteria recommended by Kozinn and Scott, UKA can only be offered to 2–10% of patients undergoing knee replacement, and this means that the surgeon is unable to gain experience and increase his or her skill in performing UKAs. When UKA is performed on an infrequent basis, the results may be suboptimal. In contrast, with the Oxford philosophy one can offer a UKA to about one in three patients undergoing a knee replacement (and maybe even higher, as suggested by some groups); this will allow the surgeon to gain experience and the patients to benefit from UKA. Preop evaluation: clinics

12. Preop evaluation: imaging What is mandatory full long standing antero- posterior weight-bearing view (hip and ankle included) full long standing antero- posterior weight-bearing view (hip and ankle included) true lateral view true lateral view

13. Preop evaluation: imaging What is mandatory -45° flexed-knee postero-anterior weight bearing view (schuss or Rosenberg view)

14. Preop evaluation: imaging Imaging: what is mandatory skyline (axial) view at 30° of flexion or under weight bearing to assess for the degeneration of the patella-femoral joint and tracking. skyline (axial) view at 30° of flexion or under weight bearing to assess for the degeneration of the patella-femoral joint and tracking.

15. Preop evaluation: imaging Imaging: what is useful MRI: -can be adopted as a tool to assess the situation in the opposite compartment. -can over-estimate the degree of degeneration -MRI is mandatory in diagnosing the osteonecrosis of the femoral condyle, which is a specific indication for UKA

16. Preop evaluation: imaging What is debatable between useful and necessary:  Stress x rays

17. Preop evaluation: imaging Imaging: what is useless CT scan: -Does not give additional information -Irradiation of the patient

18. Preop evaluation: imaging Imaging: what is useless Arthroscopy:  advocated by some surgeons to confirm the unilateral disease and the indication. -We do not recommend the use of the arthroscopy on a routine basis.

19. How can we evaluat morphology Radiography Radiography MRI MRI CT CT Arthroscopy Arthroscopy Radiography is a powerful tool confirm indications for UKA to plan the surgery

20. The premise behind Oxford criteria is that UKA is utilized to treat anteromedial osteoarthritis. When these criteria are present, other unnecessary contraindications such as age, weight, and the status of the patellofemoral articulation can be safely ignored without affecting the outcome of Oxford UKA. The premise behind Oxford criteria is that UKA is utilized to treat anteromedial osteoarthritis. When these criteria are present, other unnecessary contraindications such as age, weight, and the status of the patellofemoral articulation can be safely ignored without affecting the outcome of Oxford UKA. Correction of varus deformity with preservation of the anterior cruciate ligament has a protective effect on the patellofemoral joint, even if there is significant arthritic disease present. Correction of varus deformity with preservation of the anterior cruciate ligament has a protective effect on the patellofemoral joint, even if there is significant arthritic disease present. Medial UKA is a conservative procedure that can accurately correct malalignment, and restore an arthritic knee to its predisease functional status with normal kinematics and tremendous pain relief. Medial UKA is a conservative procedure that can accurately correct malalignment, and restore an arthritic knee to its predisease functional status with normal kinematics and tremendous pain relief. Mobile bearing, with its inset femoral component, may be more tolerant to patellofemoral disease than a polyradial/polycentric femoral component used in fixed-bearing UKA. Mobile bearing, with its inset femoral component, may be more tolerant to patellofemoral disease than a polyradial/polycentric femoral component used in fixed-bearing UKA. Patellar role of UKA

21. 2015 PFJ degeneration is not associated with adverse functional outcomes, or increased failure rate, in medial UKA using either a mobile bearing or fixed bearing implant

22. Ran Thein, et a l (2015) Medial UKA appears to improve PFJ congruence, presumably by increasing the external rotation of the femur as the knee flexes.

23. Thresholds using weight, age, activity, the state of the patello femoral joint the patello femoral joint and chondrocalcinosis should not be considered to be contraindications for the use of the UKR. and chondrocalcinosis should not be considered to be contraindications for the use of the UKR. 2012

24. If there is not bone loss and grooving of the lateral facet, damage to the articular cartilage of the patellofemoral joint to the extent of full-thickness cartilage loss not a contraindication to the mobile-bearing unicompartmental knee replacement

25. Neither anterior knee pain nor radiologically- demonstrated medial patellofemoral joint degeneration should be considered a contraindication to unicompartmental knee replacement. With lateral patellofemoral degeneration the situation is less well defined and caution should be observed

26. Pre-operative : implant selection Pre-operative : implant selection 1) Resurfacing 2) Measured resection Fixed vs mobile Different philosophies Different philosophies Slightly different indications Slightly different indications

27. Resurfacing Measured resection Resurfacing

29. Take home message UKA is a valid solution for unicompartmental disease of the knee. UKA is a valid solution for unicompartmental disease of the knee. Strict adhesions to indications and techniques are of paramount importance to achieve good results. Strict adhesions to indications and techniques are of paramount importance to achieve good results. Technically demanding: learning curve to be completed and skill to be maintained and updated. Technically demanding: learning curve to be completed and skill to be maintained and updated. New solutions coming up (associations of implants). New solutions coming up (associations of implants).

30. Thank you for your attention

31. Unique design features of the Oxford UKA minimize Unique design features of the Oxford UKA minimize wear and make the implant “patella friendly.” wear and make the implant “patella friendly.” Principal indications for medial UKA are anteromedial osteoarthritis and avascular necrosis Principal indications for medial UKA are anteromedial osteoarthritis and avascular necrosis (also called spontaneous osteonecrosis of the knee). (also called spontaneous osteonecrosis of the knee). There should be “bone-on-bone” contact in the affected medial compartment with a functionally intact ACL and varus correctible if present. There should be “bone-on-bone” contact in the affected medial compartment with a functionally intact ACL and varus correctible if present. Contraindications described by Kozinn and Scott are unnecessary for the Oxford UKA. Contraindications described by Kozinn and Scott are unnecessary for the Oxford UKA. Preop evaluation: clinics Oxford Group

32. Uni solo: “one finger sign” + slight AKP with only medial facet involved Beard et al The influence of the presence and severity of pre-existing patellofemoral degenerative changes on the outcome of the Oxford medial unicompartmental knee replacement Pre-operative clinical and radiological assessment of the patellofemoral joint in unicompartmental knee replacement and its influence on outcome JBJS Br, 2007. F. Benazzo, S. M. P. Rossi, L. Piovani, A. Combi, S. Perle Bi-uni und bi-uni + femoropatellarer Gelenkersatz 2012 Preop evaluation: clinics

33. Definition