Unicompartmental Knee Arthroplasty: Indications and Current Results

1. Unicompartmental Knee Arthroplasty: Indications and Current Results Natasha Holder MD, MSc PGY-1

2. Objectives • Classic indications • Expanding indications • UKR vs. TKR: current outcome studies

3. Unicompartmental Knee Arthroplasty • Preservation of normal kinematics • Lower perioperative morbidity • Accelerated patient rehabilitation • Preservation of bone stock

4. Classic Indications • Diagnosis of unicompartmental arthritis • Age >60 with low demand for activity • Weight <82 kg • ROM arc >90° with <5° flexion contracture • Angular deformity of <15° Kozinn et al. JBJS 1989:145-150

5. Contraindications • Inflammatory arthritis • Patient age < 60 • High patient activity level • Patellofemoral pain Kozinn et al. JBJS 1989:145-150

6. UKA and Age • Pennington et al. (JBJS, 2003) • Retrospective study, 46 UKA, age <60 • Survivorship of 92% at 11 years • Price et al. (JBJS (Br), 2005) • Case Series, 564 UKA, compared 2 age groups • Age <60 – Survivorship of 91% at 10 years • Age >60 Survivorship of 96% at 10 years • Cartier et al. (Ortho, 2007) • Case Series, 161 UKA, age <60 • Survivorship of 94% at 10 years, 88% at 12 years

7. UKA and Age • Kort et al. (Knee, 2007) • Case Series, 46 UKA, age <60, 2-6 yr F/U • Improved KSS and WOMAC scores • Obesity can affect outcome i.e. technical failure • Berend et al. (Orthopedics, 2007) • Case Series, 318 UKA, age 33-90, 6w-28 mo F/U • Early survivorship 98.1%, age <60 was not predictive of early failure

8. UKA and Obesity • Berend et al. (Orthopedics, 2007) • Prospective study, 318 UKA, weight 51-158kg, 150 UKA BMI >32, 6w-28 mo F/U • Early surviorship 98.1%, weight >82 or BMI >35 was not predictive of early failure

9. UKA and ACL Deficiency • Pandit et al. (JBJS (Br), 2006) • Prospective Study, compared 15 UKA with ACL reconstruction to 15 UKA with intact ACL (age, gender, F/U matched) • Oxford Knee score, KSS, Tegner activity level score, radiological assessment

10. UKA and ACL Deficiency • Pandit et al. (JBJS (Br), 2006) • ACLR had greater postoperative Oxford knee scores than ACLI • No pathological radiolucenciesor component subsidence in either group

11. UKA vs TKA • Lombardi et al. (Clin Ortho Relat Res, 2009) • Retrospective cohort, 115 UKA and 115 TKA, matched for age, gender, BMI, bilaterality • UKA selection: anteromedial OA, intact ACL, flexion deformity <15°, varus deformity <15° • TKA selection: unicompartmental OA or more extensive OA • Outcomes: ROM, KSS, LOS

13. UKA vs TKA • Newman et al. (JBJS (Br), 2009 • Prospective randomized control trial (1989-1992) with a 15 year follow up • 102 knees • Criteria: unicompartmental, intact cruciate ligaments, flexion deformity ≤ 15°, varus/valgus deformity ≤15° • Outcome: Bristol knee score • Failure: revision, Bristol score < 60

16. UKA 89.8% Survival rate • TKA 78.7% Survival rate • UKA results are comparable to TKA and have no greater tendency to fail at 15 years

17. Summary • In appropriately selected patients UKA is a successful procedure • Indications are expanding with satisfactory results • Equal survivorship to TKA in first decade • Improved functional results • Fewer complications

18. Thank you