Gait comparison of unicompartmental and total knee arthroplasties with healthy controls.
OBJECTIVE
To compare the gait of unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) patients with healthy controls, using a machine-learning approach.


METHODS
145 participants (121 healthy controls, 12 patients with cruciate-retaining TKA, and 12 with mobile-bearing medial UKA) were recruited. The TKA and UKA patients were a minimum of 12 months post-operative, and matched for pattern and severity of arthrosis, age, and body mass index. Participants walked on an instrumented treadmill until their maximum walking speed was reached. Temporospatial gait parameters, and vertical ground reaction force data, were captured at each speed. Oxford knee scores (OKS) were also collected. An ensemble of trees algorithm was used to analyse the data: 27 gait variables were used to train classification trees for each speed, with a binary output prediction of whether these variables were derived from a UKA or TKA patient. Healthy control gait data was then tested by the decision trees at each speed and a final classification (UKA or TKA) reached for each subject in a majority voting manner over all gait cycles and speeds. Top walking speed was also recorded.


RESULTS
92% of the healthy controls were classified by the decision tree as a UKA, 5% as a TKA, and 3% were unclassified. There was no significant difference in OKS between the UKA and TKA patients (p = 0.077). Top walking speed in TKA patients (1.6 m/s; 1.3 to 2.1) was significantly lower than that of both the UKA group (2.2 m/s; 1.8 to 2.7) and healthy controls (2.2 m/s; 1.5 to 2.7; p < 0.001).


CONCLUSIONS
UKA results in a more physiological gait compared with TKA, and a higher top walking speed. This difference in function was not detected by the OKS. Cite this article: Bone Joint J 2016;98-B(10 Suppl B):16-21.
MSk Lab, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
G G
GG
Jones
MSk Lab, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
M
M
Kotti
MSk Lab, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
A V
AV
Wiik
MSk Lab, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
R
R
Collins
MSk Lab, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
M J
MJ
Brevadt
Imperial College NHS Trust, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
R K
RK
Strachan
MSk Lab, Imperial College London, Charing Cross Hospital, Fulham Palace Road, London, W6 8RF, UK.
J P
JP
Cobb
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D016022:Case-Control Studies; D005080:Exercise Test / Q000379:methods; D005684:Gait / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000503:physiopathology; D000069550:Machine Learning; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery*; D020127:Recovery of Function; D012720:Severity of Illness Index; D016896:Treatment Outcome; D016138:Walking / Q000502:physiology; D055815:Young Adult
Gait; Patient-reported outcome measures; Total knee arthroplasty; Unicompartmental knee arthroplasty
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