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

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

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

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

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

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

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

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

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

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

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

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

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

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

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.

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.

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.

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.

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

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.

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.

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

Coronal plane leg alignment Normal alignment

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

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

Coronal alignment Normal alignment - varus Tibia Vara

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

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.

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

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

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

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

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.

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.

FFD – present preoperatively Short posterior Capsule

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

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

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): 469-474.

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 www.biomet.com. 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.