1. Oxford® Partial Knee Surgical Principles
Advanced Instructional Course
Material intended solely for attendees. Not for distribution.

2. Overview Principles different from fixed bearing UKR and TKR Topics
Dislocation
Component position, spoons & G-clamps
Alignment
Ligament release
FFD

3. Dislocation For dislocation need both
Distraction of joint surfaces
Accurate balance, Protect MCL
Displacement of bearing
Prevent impingement
General perception is that putting the bearing in tight prevents dislocation. Incorrect
Can causes pain and slow recovery
Normal ligament laxity should be restored
In added and incorrect in red

4. Spoons and G-clamps Stylus to determine tibial cut depth. Adjusts for
Bearing thickness
Ligament laxity
Guide for femoral component size.
Positions EM guide

5. Femoral component size
Spoon has radius of femoral component.
Estimate where normal distal femoral cartilage was
Select spoon of appropriate size
3-4mm gap
Optimal spoon
Too large

6. Bearing thickness 3 G clamp links spoon EM guide
3 clamp for 3 bearing: cuts 6mm below joint below joint line (3mm plateau, 3mm bearing) 3

7. Bearing thickness 4 G clamp links spoon EM guide
3 clamp for 3 bearing: cuts 6mm below joint below joint line (3mm plateau, 3mm bearing)
4 clamp for 4 bearing: cuts 7mm off, removes 1mm more bone than 3 clamp 4
removes 1mm more bone than 3 clamp added

8. 3 Bearing thickness 3 G clamp links spoon EM guide
3 clamp for 3 bearing: cuts 6mm below joint below joint line (3mm plateau, 3mm bearing) 3

9. 4 Bearing thickness 4 G clamp links spoon EM guide
3 clamp for 3 bearing: cuts 6mm below joint below joint line (3mm plateau, 3mm bearing)
4 clamp for 4 bearing: cuts 7mm off, removes 1mm more bone than 3 clamp 4

10. Tighten MCL Some cases slight MCL laxity in flexion
Either deep tibial defect or lax ligaments
Ligament must be tight
Use thicker spoons
1mm, 2mm or 3mm

11. Tighten MCL 1 spoon loose
Cuts too much bone as bearing inserted with ligament tight

12. Tighten MCL 1 spoon loose
Cuts too much bone as bearing inserted with ligament tight
3 spoon correct, removes less bone

13. 1 spoon Tighten MCL 1 spoon loose
Cuts too much bone as bearing inserted with ligament tight
1 spoon

14. 3 spoon Tighten MCL 1 spoon loose
Cuts too much bone as bearing inserted with ligament tight
3 spoon correct, removes less bone
3 spoon

15. Component position medio-lateral
Vertical cut just medial to apex of medial spine
Determines position of tibial plateau
Just added
Material intended solely for attendees. Not for distribution.

16. Component position medio-lateral
Femoral Guide
Position 6mm hole in guide central on condyle
Position of drill hole determines position of component
Material intended solely for attendees. Not for distribution.

17. Component position medio-lateral
Ensure bearing does not jam against wall. If so - Recut
Bearing ideally 1mm from wall. Prevents spinning
Material intended solely for attendees. Not for distribution.

18. Coronal plane Alignment
Varus/valgus depends on bearing thickness
Bearing thickness chosen to restore ligament tension
Alignment restored to pre-disease state
Material intended solely for attendees. Not for distribution.

19. Coronal plane Alignment
Does not depend on component alignment (cf TKR)
Material intended solely for attendees. Not for distribution.

20. Coronal plane Alignment
Does not depend on component alignment (cf TKR)
Components are spherical.
Alignment is forgiving
Material intended solely for attendees. Not for distribution.

21. Coronal plane Alignment
Does not depend on component alignment (cf TKR)
Components are spherical.
Alignment is forgiving
Material intended solely for attendees. Not for distribution.

22. Coronal plane leg alignment
Head
Coronal plane leg alignment
Leg alignment confusing
Distinguish between:
Intra-articular deformity
Genu varum
Extra-articular deformity
Tibia vara usually
Both contribute to overall leg alignment

23. Coronal plane leg alignment
Normal alignment

24. Coronal plane leg alignment
Normal alignment
Medial Compartment OA
Genu Varum, lax MCL

25. Coronal plane leg alignment
Normal alignment
Medial Compartment OA
Genu Varum, lax MCL
Medial UKR
MCL normal length
Genu Varum corrected
Normal alignment restored

26. Coronal alignment
Normal alignment - varus
Tibia Vara

27. Coronal alignment Normal alignment - varus Tibia Vara
Medial Compartment OA
Genu Varum, lax MCL

28. Coronal alignment Normal alignment - varus Tibia Vara
Medial Compartment OA
Genu Varum, lax MCL
Medial UKR
MCL normal length
Genu Varum corrected
Normal Varus restored
Does not compromise outcome*1
Not a cause of failure
Reference added. Line colour changed. Order of word changed in Not a cause of failure in our experienced
*Improper alignment of implant components may result in unusual stress conditions which may lead to subsequent reduction in the service life of the prosthetic components.
Gulati et al., JBJS[Br], 20091
Material intended solely for attendees. Not for distribution.

29. Ligament Release Normal knee ≥ 20º flexion LCL loose
MCL, ACL, PCL tight
Material intended solely for attendees. Not for distribution.

30. UKR No release Ligaments normal ≥ 20º flexion LCL loose
MCL, ACL, PCL tight
Material intended solely for attendees. Not for distribution.

31. TKR ACL divided PCL de-functioned LCL must be tight
Material intended solely for attendees. Not for distribution.

32. TKR ACL divided PCL de-functioned LCL must be tight
Lateral side distracted
Joint surface resection
Material intended solely for attendees. Not for distribution.

33. TKR ACL divided PCL de-functioned LCL must be tight
Lateral side distracted
Joint surface resection
Medial release required to balance gaps
Material intended solely for attendees. Not for distribution.

34. TKR TKR implanted Distracts joint
For full extension posterior capsule has to be lengthen more than normal
FFD do not correct after TKR
Material intended solely for attendees. Not for distribution.

35. FFD – present preoperatively
Short posterior Capsule

36. Posterior capsule not released
Anterior osteophytes
must be removed
Posterior capsule slowly returns to normal length.
FFD halves during operation, typically corrects during 1st yr
KRB edit to be made - Slide 36 need to demonstrate the anterior bone that needs to be removed or that has been removed to prevent late impingement with FFD.  Currently the bone isn to removed and the arrow is pointing to the wrong place

37. Key points Dislocation Avoid impingement, protect MCL
Spoons & G-clamps reliably guide tibial cut for selected bearing thickness
Restore pre-disease alignment, by restoring normal ligament tension (not tight)
Accept FFD – will correct with time if osteophytes removed

38. References
Gulati, A., et al. "The effect of leg alignment on the outcome of unicompartmental knee replacement." Journal of Bone & Joint Surgery, British Volume 91.4 (2009):

39. THANK YOU.
Zimmer Biomet, does not practice medicine. This perioperative plan is utilized by training surgeons. Each surgeon is responsible for determining the appropriate device, technique and overall treatment for each individual patient.  With respect to any pharmaceutical or other product, please consult the appropriate product labelling or other applicable sources. Please check for country product clearances and reference product specific instructions for use.
All trademarks herein are the property of Zimmer Biomet, or its affiliates unless otherwise indicated. This material is intended for attendees at the Zimmer Biomet Advanced Instructional Course.   It is not to be redistributed, duplicated or disclosed without the expressed written consent of Zimmer Biomet.
The content herein is based on the personal experience of the presenters.
The Oxford Partial Knee is intended for use in individuals with osteoarthritis or avascular necrosis limited to the medial compartment of the knee and is intended to be implanted with bone cement. The Oxford Knee is not indicated for use in the lateral compartment or for patients with ligament deficiency. Potential risks include, but are not limited to, loosening, dislocation, fracture, wear, and infection, any of which can require additional surgery.
For complete product information, including indications, contraindications, warnings, precautions and potential adverse effects, see the package insert at
Oxford Legal Manufacturer:
Biomet UK Limited
Waterton Industrial Estate
Bridgend
CF31 3XA
United Kingdom
Presenting surgeons have received financial remuneration from Biomet.
This material is intended for health care professionals and Zimmer Biomet sales force attending a Zimmer Biomet Oxford Partial Knee training course. Distribution to any other recipient is prohibited.