Early functional outcome after lateral UKA is sensitive to postoperative lower limb alignment
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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.
KeywordsUnicompartmental 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.
- 1.Annual Report 2014 Australian Hip and Knee Arthroplasty Register (2014). https://aoanjrr.dmac.adelaide.edu.au/documents/10180/172286/AnnualReport2014
- 7.Chatellard R, Sauleau V, Colmar M, Robert H, Raynaud G, Brilhault J, Societe d’Orthopedie de Traumatologie de lO (2013) Medial unicompartmental knee arthroplasty: Does tibial component position influence clinical outcomes and arthroplasty survival? Orthop Traumatol Surg Res 99(4 Suppl):S219–S225CrossRefPubMedGoogle Scholar
- 10.Evans JD (1996) Straightforward statistics for the behavioral sciences. Brooks/Cole Publishing, Pacific GroveGoogle Scholar
- 29.World Health Organization (1995) Physical status: The use and interpretation of anthropometry. Report of a WHO Expert Committee. World Health Organization Technical Report, Series 854, pp 1–452Google Scholar
- 30.Roche M, O’Loughlin PF, Kendoff D, Musahl V, Pearle AD (2009) Robotic arm-assisted unicompartmental knee arthroplasty: preoperative planning and surgical technique. Am J Orthop (Belle Mead NJ) 38(2 Suppl):10–15Google Scholar
- 33.Scott RD, Cobb AG, McQueary FG, Thornhill TS (1991) Unicompartmental knee arthroplasty: eight- to 12-year follow-up evaluation with survivorship analysis. Clin Orthop Relat Res 271:96–100Google Scholar
- 34.Sebilo A, Casin C, Lebel B, Rouvillain JL, Chapuis S, Bonnevialle P, members of the Societe d’Orthopedie et de Traumatologie de lO (2013) Clinical and technical factors influencing outcomes of unicompartmental knee arthroplasty: retrospective multicentre study of 944 knees. Orthop Traumatol Surg Res 99(4 Suppl):S227–S234CrossRefPubMedGoogle Scholar