Is the Kinect system suitable for evaluation of the hip joint range of motion and as a screening tool for femoroacetabular impingement (FAI)?
BACKGROUND
In the clinical evaluation of femoroacetabular impingement (FAI), there is a lack of quantitative, reliable and informative assessment methods for the overall functional capability of an individual.


OBJECTIVE
We compared clinical and radiological measurements of the hip joint with a new methodology based on the concept of 3-dimensional reachable workspace using Microsoft Kinect.


METHODS
We assessed the correlation between the alpha angle of Nötzli on full-length radiographs and the clinical internal rotation. We evaluated the accuracy of joint positions and angles of the hip between the Kinect system and clinical examination including range of motion (ROM).


RESULTS
The results of our clinical trial with 24 study participants showed a significant difference between normal internal rotation (> 21°) and reduced internal rotation (⩽ 21°) in comparison to the radiological alpha angle of Nötzli (P=0.026). The acquired reachable Kinect data demonstrated a moderate agreement between the Kinect and clinical examination (correlation coefficients between 0.230 and 0.375).


CONCLUSIONS
The findings suggest that a higher grade alpha angle of Nötzli accompanies reduced clinical internal rotation. The Kinect system provides reliable results of hip ROM. However, further test series must be performed for the application of Kinect in the clinical evaluation of FAI.
Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
Matthias
M
Lahner
Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
Dennis
D
Mußhoff
Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
Christoph
C
von Schulze Pellengahr
Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
Roland
R
Willburger
Biomechanics Laboratory, Department of Sport and Movement Sciences, University of Duisburg-Essen, Essen, Germany.
Marco
M
Hagen
Department of Orthopaedic Surgery, Physical Medicine and Rehabilitation, University Hospital of Munich, Campus Großhadern, Munich, Germany.
Andreas
A
Ficklscherer
Faculty of Health Sciences, University of Witten/Herdecke, Witten, Germany.
Lars Victor
LV
von Engelhardt
Sportklinik Duisburg, Duisburg, Germany.
Ole
O
Ackermann
Department of Dermatology, Venereology and Allergology, Ruhr-University Bochum, Bochum, Germany.
Nina
N
Lahner
Department of Orthopaedic Surgery, St. Josef-Hospital, Ruhr-University Bochum, Bochum, Germany.
Gregor
G
Vetter
D000328:Adult; D053587:Arthrometry, Articular / Q000379:methods*; D005260:Female; D057925:Femoracetabular Impingement / Q000175:diagnosis* / Q000000981:diagnostic imaging; D006621:Hip Joint / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D010808:Physical Examination / Q000379:methods; D011859:Radiography; D016059:Range of Motion, Articular / Q000502:physiology*; D012680:Sensitivity and Specificity
Kinect system; alpha angle of Nötzli; femoroacetabular impingement (FAI); goniometer; range of motion (ROM)