Early functional outcome after lateral UKA is sensitive to postoperative lower limb alignment

  • J. P. van der ListEmail author
  • H. Chawla
  • J. C. Villa
  • H. A. Zuiderbaan
  • A. D. Pearle



The predictive role of patient-specific characteristics and radiographic parameters on medial unicompartmental knee arthroplasty (UKA) outcomes is well known, but knowledge of these predictors is lacking in lateral UKA. Therefore, purpose of this study was to assess the predictive role of these parameters on short-term functional outcomes of lateral UKA.


In this retrospective cohort study, Western Ontario and McMaster Universities Arthritis Index scores were collected at 2-year follow-up (median 2.2 years, range 2.0–4.0 years) in 39 patients who underwent lateral UKA. Patient-specific characteristics included age, BMI and gender, while radiographic parameters included osteoarthritis severity of all three compartments and both preoperative and postoperative hip-knee-ankle alignment.


BMI, gender, age and preoperative valgus alignment were not correlated with functional outcomes, while postoperative valgus alignment was correlated with functional outcomes (0.561; p = 0.001). Postoperative valgus of 3°–7° was correlated with better outcomes than more neutral (−2° to 3° valgus) alignment (96.7 vs. 85.6; p = 0.011). Postoperative alignment was a predictor when corrected for patient-specific characteristics (regression coefficient 4.1; p < 0.001) and radiological parameters (regression coefficient 3.8; p = 0.002).


Postoperative valgus alignment of 3°–7° was correlated with the best short-term functional outcomes in lateral UKA surgery, while patient-specific parameters and preoperative alignment were not correlated with functional outcomes. Based on these findings, a surgeon should aim for valgus alignment of 3°–7° when performing lateral UKA surgery for optimal functional outcomes.

Level of evidence

Prognostic study, Level II.


Unicompartmental knee arthroplasty Lateral UKA Alignment Patient-reported functional outcomes Predictors 


Compliance with ethical standard

Conflict of interest

The authors declare that they have no conflict of interest.


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Copyright information

© European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA) 2015

Authors and Affiliations

  • J. P. van der List
    • 1
    Email author
  • H. Chawla
    • 1
  • J. C. Villa
    • 1
  • H. A. Zuiderbaan
    • 2
  • A. D. Pearle
    • 1
  1. 1.Computer Assisted Surgery Center, Department of Orthopaedic Surgery, Hospital for Special SurgeryWeill Medical College of Cornell UniversityNew YorkUSA
  2. 2.Department of Orthopaedic SurgerySpaarne HospitalHoofddorpThe Netherlands

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