Unicompartmental Disclosure Knee Arthroplasty-  None relevant to this topic  Consultant: Principles and Practice Stryker Trauma Mark T. Dahl, M.D. Nuvasive TRIA University of Minnesota Gillette Children’s Specialty Healthcare Editorial Board: JBJS,CORR, Journal of Trauma, Journal Orthopaedic Research

Today’s Goals History

 Describe Unicompartmental Knee Replacement  JBJS McIntosh 1958  Indications  St Georg 1969  Principles  Marmor 1972  Management  Ahlback Unicompartmental disease does not “spread to total involvement”  Results  Surgeon’s General impression  Pitfalls “UKA harder than TKA”

Early Design Goodfellow . O’connor

1974 Oxford  Curved metal femur on flat plastic tibia Mobile bearings Marmor 1972 Literature GLUT There is the General Opinion… “Unicompartmental Knee Replacement” UKA is harder than TKA and thus, less successful for the average surgeon Pubmed search: 18,403 articles Review Articles 1891 Meta-Analysis 332

Causes of knee deformity Post-traumatic  Congenital  Constitutional  Facture malalignment  Physeal arrest  Leads to uneven load  Metabolic  Osteopathy  Postrauma  Joint destruction  Cartilage loss

Post-traumatic OCD / Avascular Necrosis

 Intraarticular damage  Microcirculation damage  Leads to poor chondral repair  Dysplasias  Steroids  Alcohol  unknown Aging Indications for Uni

 Leads to meniscal and hyaline wear  Monocompartment osteoarthritis  Uneven load  Active  Minimal contracture  Pain localization

Symptoms of Anatomic Features Unicompartmental Arthritis  Cruciates normal  Pain localized  Anterior tibial cartilage eroded  Pain present standing  Anterior femoral cartilage eroded  Pain severe walking  Opposite cartilage full thickness  Pain absent sitting  Collaterals normal length  Extended knee in varus  Posterior capsule short

Incidence Medial to Lateral X-ray Assessment

10:1 Why partial knee? Patient Selection for UKA

Patients report a more “normal feel”  Isolated medial or lateral end stage disease • Better motion  Preserved ligaments • Better kinematics  Preserved ROM • Less recovery pain than TKA UKA TKA  Adequate bone stock • Faster recovery • Less blood loss

Contraindications Deciding on Uni vs Osteotomy

 Inflammatory arthritis  Global pain  Knee stiffness  AT least two office visits  Ligament damage  LISTEN to expectations  Osteoporosis  Get MRI  Extreme deformity  Review prior scope images  Extreme obesity  Nuanced discussion

HTO over UKA Osteotomy Expectations Younger and more active HTO prevention

 Impose No restrictions  90% Pain relief  Improved function  Delay / Avoid TKA 10 years Practice Patterns 2014 High tibial osteotomy versus unicompartmental joint replacement : 7–10-year follow-up prospective Unicompartmental Knee Arthroplasty randomised study Versus High Tibial Osteotomy: Stukenborg-Colsman,Wirth,Lazovic,Wefer Benedict U.NwachukwuMD, MBAaFrank M.McCormickMDbWilliam W.SchairerMDaRachel M.FrankMDcMatthew T.ProvencherMDdMartin UNI > HTO W.RocheMDa 70 vs 60 % survival at 10 years 2007-2011 Lower complications in UNI UKA up 5% Age and activity expectations HTO down 4%

UNI Recovery Rehabilitation

 In-hospital Recovery: 1-2 days  Significant Functional Improvement: 6 weeks – 3 months  Physical Therapist day of surgery  Maximal Improvement: 6 – 12 months  Ambulate day of surgery  Regain muscle strength  Increase range of motion  No CPM

Outpatient Unicompartmental Knee TRIA 2016-2017 Arthroplasty Is Safe to Perform at an Ambulatory Surgery Center A Comparative Study of Early Post-Operative  10 surgeons Complications  105 UNI John P. Cody, Kiel J. Pfefferle, Deborah J. Ammeen, Kevin B. Fricka  200 TKA  0 infections  Equivalent results  2 hospital admissions  Lower cost for outpatient  Anxiety  Feather allergy Limitations Limitations After Surgery After Uni Surgery  Athletics that place  Avoid excessive stress should  Construction work be avoided.  Certain types of heavy labor  Contact sports  Occupations that involve repeated  Long distance Running climbing  Frequent jumping  Contact sports

Eight Hundred Twenty-Five Medial Unicompartmental Knee 48 yo male Arthroplasties: The First 10-Year US Multi-Center Survival Analysis

Omr K. Alnachoukati, John W. Barrington, Keith R. Berend, Michael C. Kolczun, Roger H. Emerson, Adolph V. Lombardi Jr., David R. Mauerhan p677–683

90%

Manages arboretum RTW 5 weeks 60 yo with lateral pain Exposure with lateral Osteonecrosis more difficult

56 yo female

Long distance walker Controversies

 Sports  Youth  Obesity  ACL Combined UNI + ACL Dodd, Murray JBJS 52 yo elite runner  Medial joint line pain  3 year follow suggests good durability  Multiple scopes  I don’t advise  Difficulty walking  Desires to continue running

 HTO !!!

Still Running At 14 years, hurts too much to run 50 m / week Right medial joint line pain 12 years after bilateral States: “Doc, I will run…no matter what” HTO

55 year old UNI after HTO ? Now 6 years of running 9 years s/p UKA 50 miles / week  Runs 5 miles per day  Not recommended by Oxford group  Pain for past 6 months  Yet, I perform if alignment neutral, and all other criteria met Osteolysis, Aspirate and labs Revision with impaction normal. Can I still run? graft Agreed to quit running

Undersize components will Obesity and UKA? subside !

 Literature mixed  I have no set BMI  But extensive discussion

22 yo medical student Youth and UKA familial osteonecrosis

 s/p scopes, OCD pinning, osteochondral allograft, distal femoral osteotomy Custom tantalum support The difficulty with partial knees noncompliant & Pain free at 5 years • Selection • inaccurate placement • Difficult to consistently restore: • Tibial slope • Coronal alignment • Femoral rotation • Limb alignment • Implant congruency

Causes of Failure Causes of Failure Australian registry n=4362 Dahl n=13/753 Loosening 3 Loosening 45 % Disease progression 3 Disease progression 27 Pain 4 Pain 10 Bearing dislocation 4 Infection 4 Infection 2 Fracture 2 Fracture 0 Malalignment 1 Malalignment 0 Poly wear 1 Poly wear 0 Unstable 1 Unstable 0

Technical failures with manual Mobile bearing dislocation partial knees

• Subjective “feel” for balance  Requires TKA • Pin stress risers  Results from MCL injury • No mid‐flexion knowledge  Swedish registry 2.3 % • Difficult to reference “slope”  Dahl 4 / 213 Robotic UKA, Rhodes et al Is robotics the solution? Proves nothing

CT Planning Positioning

Patient-specific pre-operative Surgeon-controlled plan enables more accurate intra-operative adjustments implant positioning.9,10,11 can be made to optimize implant placement.12

Robotic UKA

• 1135 knees at minimum 2-year follow up • 909 knees 2-year follow up Conclusions • 46 knees 5-year follow up

Too early to say

My OPINION in UKA knees Clinical Audit

 Patients are extraordinarily Happy  33 years  Poor Patient Selection is the biggest Factor in the need for revision  1,257 HTO  Osteoporosis  3,512 TKA  Disease progression  753 UKA  Mobile bearing dislocation 2 %  Pain rare  Malposition rare Conclusions: Unicompartmental Thank You Knee Arthroplasty

 Careful patient selection  Ideal indications  Ideal expectations  Ideal surgery  Excellent, lasting results