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

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

Unicompartmental Knee Arthroplasty  Preservation of normal kinematics  Lower perioperative morbidity  Accelerated patient rehabilitation  Preservation of bone stock

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:

Contraindications  Inflammatory arthritis  Patient age < 60  High patient activity level  Patellofemoral pain Kozinn et al. JBJS 1989:

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

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

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

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

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

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

UKA vs TKA  Newman et al. (JBJS (Br), 2009  Prospective randomized control trial ( ) 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

 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

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

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