Unicompartmental Knee Arthroplasty- Unicompartmental Knee Arthroplasty

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

Today’s Goals History

 Medial and Lateral Unicompartmental Knee Replacement  Hemiarthroplasty of the knee using a space occupying prosthesis for painful varus or  Not cover Patellofemoral valgus deformity  Indications  JBJS McIntosh, DL1958;40-A: 1431  Technique  Results

History Ahlback 1968

 St Georg 1969 Longitudinal studies suggested  Marmor 1972 unicompartmental osteoarthritis  Ahlback Unicompartmental disease DOES NOT inevitably “spread” to the does not “spread to total involvement” remainder of the knee  General impression “UKA harder than TKA” Tricompartmental General Opinion

 Gradually surgical opinion that knee OA  UKA is harder than TKA and therefore less involved the ENTIRE knee successful for the average surgeon  Designers concentrated on tricompartmental knee designs, thus survival of UKA < TKA

Pubmed search “Unicompartmental Knee Early Design Replacement”  Polycentric metal femur on flat plastic tibia Marmor 1972 Search Results: 18,403 articles Review Articles 1891 Meta-Analysis 332

Goodfellow . O’connor Etiology of knee deformity

 1974 Oxford  Congenital  Mobile bearings  Constitutional  Physeal arrest  Metabolic  Osteopathy  Postrauma  Joint destruction  Cartilage loss Physical signs of Indications for Uni Anteromedial Arthritis

 Pain localized  Monocompartment osteoarthritis  Pain present standing  Active  Pain severe walking  Minimal contracture  Pain absent sitting  Pain localization  Extended knee in varus

Medial compartment Anatomic Features osteoarthritis is assessed in three key areas  Cruciates normal  Anterior tibial cartilage eroded, never posterior 1. Deformity magnitude  Anterior femoral cartilage eroded, not 2. ligament stability posterior 3. cartilage condition  Lateral cartilage full thickness > osteoarthritis  MCL normal length  Posterior capsule short

Unicompartmental vs Clinical Audit Total Knee Arthroplasty

 Osteoarthritis of the knee – Common  33 years cause of painful loss of mobility  Often limited to one compartment  1,257 HTO  3,512 TKA  753 UKA Incidence Medial to Lateral Broad Considerations for Uni? Cultural Practical 10:1 Effort

Evidence to consider a partial knee? Why partial knee?

When patient selected well, done well, … Patients report a more “normal feel” • Few serious complications1, • Better range of motion • Earlier rehab2 • Better kinematics • High Satisfaction3 • Less recovery pain than TKA • Accelerated recovery • High Survivorship4 • Faster return to work UKA TKA • Less blood loss • Expanding indications

Advantages of UKA Goal: A satisfied patient

 Less invasive 95 % pain relief  Quicker recovery  Less expensive Greater activity  Better proprioception Minimal morbidity  Better kinematics Survival > 15 years  Better gait Then, Why don’t more surgeons do UKA? Patient Selection for UKA

 Early design failures  Isolated medial or lateral end stage disease  Patient selection is subjective  Preserved ligaments  Residency training bias  Preserved ROM  PFJ concerns  Adequate bone stock  Longevity concerns MVI_3063.AV  Technical difficult  It takes practice!!!

Patient Selection Contraindications  No Inflammatory disease  Results unpredictable  Inflammatory arthritis  Varus   15 degrees maximum Global pain  Pain location  Knee stiffness  Unilateral joint line  Ligament damage  X-ray  Full length standing  Stress view

Contraindications Contraindications to Uni

 Osteoporosis  excess pain as measured with Visual  Extreme deformity Analog Scale (VAS)  Extreme obesity  pain localization drawings more diffuse and dramatic then expected Patient Assessment Dynamic Considerations

 Pain localization  Range of motion  Gait observed - dynamic, thrust, indicating ligamentous laxity

Decision Time X-ray Assessment HTO/DFO vs UKA vs TKA

 2 visits  Nuanced discussion Decision Time DFO vs UNI HTO vs UKA

 2 visits  Nuanced discussion

HTO over UKA Osteotomy Expectations

 Impose No restrictions  90% Pain relief  Improved function  Delay / Avoid TKA 10 years

Deciding on Uni vs Osteotomy My patient observations

• Generally full ROM and little laxity or  AT least two office visits deformity • No anterior pain with squat test  LISTEN to expectations • Minimal patellar crepitus • Good cartilage thickness on merchant’s  Get MRI view (may accept small osteophytes) • Narrowing on standing AP or skier’s  Review prior scope images view • Minimal lateral subluxation on standing AP SPONK

Cases

60 yo with lateral pain Manages arboretum 48 yo male RTW 5 weeks

52 yo elite runner Running 50 m / week 12 years after bilateral  Medial joint line pain HTO  Multiple scopes  Difficulty walking  Desires to continue running

Now hurts too much to run Now 6 years of running Right medial joint line pain 50 miles / week States: “I will run…no matter what” Reports no pain 55 year old Osteolysis, Aspirate and labs 9 years s/p UKA normal. Can I still run?  Told “running is harmless on your uni”  Runs 5 miles per day  Pain for past 6 months

Revision with impaction graft Agreed to quit Obesity and UKA? running

 Literature mixed

6 weeks ACL and Uni?

22 yo medical student Youth and UKA familial osteonecrosis

 s/p scopes, OCD pinning, osteochondral allograft, distal femoral osteotomy

Options

 Hemiallograft  TKA Mobile bearing Partial Customize with Tantalum support Knee Components

56 yo female

KA Medial OA 50 year old male The difficulty with partial knees • Selection • inaccurate placement • Difficult to consistently restore: • Tibial slope • Coronal alignment • Femoral rotation • Limb alignment • Implant congruency

Problems Partial knee failures and complications

 6 mm poly  Wear and distortion  Thicker poly  Persisting distortion  Metal back ---- thinner poly

Loosening and lysis associated with malalignment and under-correction. Scott et al JOA7

Causes of Failure Causes of Failure Australian registry n=4362 Dahl n=12/753 Loosening 3 Loosening 45 % Disease progression 3 Disease progression 27 Pain 4 Pain 10 Bearing dislocation 4 Infection 4 Infection 1 Fracture 2 Fracture 0 Malalignment 1 Malalignment 0 Poly wear 1 Poly wear 0 Unstable 1 Unstable 0 Technical failures with manual My experience in UKA knees partial knees

• Subjective “feel” for balance  Poor Patient Selection is the biggest Factor in the need for revision • Pin stress risers  Osteoporosis • No mid‐flexion knowledge  Disease progression • Difficult to reference “slope”  Mobile bearing dislocation  Pain

Inconsistent outcomes in Mobile bearing dislocation manual approach

 Requires TKA  Results from MCL injury  Swedish registry 2.3 %  4 / 213  I avoid mobile bearing

MAKPKA-PRE-21

Is robotics the solution? Robotic UKA

CT Planning • 1135 knees at minimum 2-year follow up Positioning Implants • 909 knees 2-year follow up • 46 knees 5-year follow up

Too early to say

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, Rhodes et al Robotic UKA, Rhodes et al

Swedish and Australian at 7 years

UKA is more cost-effective than Robotic knees TKA in patients over 65 14 2-Year follow up Methodology • 9/909 reported revisions • Markov model constructed using UKA and TKA data from Swedish Knee Arthroplasty Register, ‒ 3 for pain published literature, HCUP government database, and HSS registry ‒ 3 for infection • Assumption: UKA and TKA experience same ‒ 3 for implant loosening post‐operative increase in quality of life • 0.9% revision rate at 2 years Key Results • 92% patient satisfaction • In patients >65, UKA was dominant over TKA primarily due to higher rehab costs of TKA, even with higher UKA revision rates • UKA will become dominant in younger patients if UKA shows an improved QOL and reduced revision rate

UKA References Thank You 1. Morris et al. Mortality and perioperative complications after unicompartmental knee arthroplasty. The Knee 20 (2013) 218‐220 2. Borus et al. UKA Patients Return to Function Earlier than TKA Patients. ISTA 27th Annual Congress; September 24‐27, 2014. Baltimore, MD

3. Conditt, M; Coon, T; Roche, M; Dounchis, J; Borus, T; Buechel, F; Branch, S; Pearle, A. Short to Mid Term Survivorship of Robotically Assisted UKA: A Multicenter Study. ISTA 27th Annual Congress; September 24‐27, 2014, Kyoto, Japan.

4. Institute for Healthcare Improvement Triple Aim Initiative. http://www.ihi.org/engage/initiatives/tripleaim/Pages/default.aspx. Accessed October 16, 2015.

5. Jones et al. Accuracy of UKA implant positioning and early clinical outcomes in a RCT comparing Robotic Assisted and Manual Surgery. 2013 CAOS International Conference, Orlando FL.

6. AUSTRALIAN ORTHOPAEDIC ASSOCIATION NATIONAL JOINT REPLACEMENT REGISTRY. Annual Report 2014.

7. Hernigou et al. Alignment Influences Wear in the Knee after Medial Unicompartmental Arthroplasty. CLINCIAL ORTHOPAEDICS AND RELATED RESEARCH. Number 423, pp.161‐165

8. Cost‐effectiveness of unicompartmental and total knee arthroplasty in elderly low‐demand patients. A Markov decision analysis. Slover J et al. J Bone Joint Surg Am. 2006 Nov;88(11):2348‐55. http://dx.doi.org/10.2106/JBJS.E.01033

9. Robotic Arm‐Assisted UKA Improved Tibial Component Alignment: A Pilot Study. Lonner, JH; John, TK; Conditt, MA. Clin Orthop Relat Res. July 2009. 468(1):141‐6.

10. Accuracy of Dynamic Tactile‐Guided Unicompartmental Knee Arthroplasty. Dunbar, NJ; Roche, MW; Park, BH; Branch, SH; Conditt, MA; Banks, SA. Journal of Arthroplasty. May 2012. 27(5): 803‐808.e1.

11. Robotic‐Arm Assisted Unicompartmental Knee Arthroplasty Lonner, JH. Seminars in Arthroplasty. 2009. 20(1): 15‐22.

12. Robotic Assisted THA: Reduce Outliers and Predictable Outcomes. Illgen R. 43rd Annual Course: Advances in Arthroplasty, October 22‐25, 2013, Cambridge, MA.

13. Unicondylar Knee Arthroplasty vs Total Knee Arthroplasty: Are We Able to Create the Forgotten Joint. Pearle AD, et al,. 14th Annual CAOS Meeting, June18‐21, 2014, Milan, IT.

14. Effect of Age on Cost effectiveness of UKA vs TKA in the US. Pearle A, Ghomrami H. J Bone Joint Surg Am. 2015; 97:396‐402

15. The cost‐effectiveness of surgical treatment of medial unicompartmental knee osteoarthritis in younger patients: a computer model‐ based evaluation. Konopka, JF et al. J Bone Joint Surg Am. 2015 May 20;97(10):807‐817. http://dx.doi.org/10.2106/JBJS.N.00925

16. Medial unicondylar knee arthroplasty improves PF congruence: a possible mechanistic explanation for poor association between PF degeneration and clinical outcomes. Thein R, Pearle AD, et al,. 14th JOA 2015. 1. Morris et al. Mortality and perioperative complications after uReferencesnicompartmental knee arthroplasty. The Knee 20 (2013) 218‐220 2. Borus et al. UKA Patients Return to Function Earlier than TKA Patients. ISTA 27th Annual Congress; September 24‐27, 2014. Baltimore, MD