title: Principal component modeling of isokinetic moment curves for discriminating between the injured and healthy knees of unilateral ACL deficient patients.
abstract: Bilateral knee strength evaluations of unilateral anterior cruciate ligament (ACL) deficient patients using isokinetic dynamometry are commonly performed in rehabilitation settings. The most frequently-used outcome measure is the peak moment value attained by the knee extensor and flexor muscle groups. However, other strength curve features may also be of clinical interest and utility. The purpose of this investigation was to identify, using Principal Component Analysis (PCA), strength curve features that explain the majority of variation between the injured and uninjured knee, and to assess the capabilities of these features to detect the presence of injury. A mixed gender cohort of 43 unilateral ACL deficient patients performed 6 continuous concentric knee extension and flexion repetitions bilaterally at 60°s(-1) and 180°s(-1) within a 90° range of motion. Moment waveforms were analyzed using PCA, and binary logistic regression was used to develop a discriminatory decision rule. For all directions and speeds, a statistically significant overall reduction in strength was noted for the involved knee in comparison to the uninvolved knee. The discriminatory decision rule yielded a specificity and sensitivity of 60.5% and 60.5%, respectively, corresponding to an accuracy of ∼62%. As such, the curve features extracted using PCA enabled only limited clinical usefulness in discerning between the ACL deficient and contra lateral, healthy knee. Improvement in discrimination capabilities may perhaps be achieved by consideration of different testing speeds and contraction modes, as well as utilization of other data analysis techniques.
authors.affiliation: Resource Environmental Associates Ltd., Markham, Ontario, Canada; School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada; Human Mobility Research Centre, Syl & Molly Apps Medical Research Centre, Kingston General Hospital, Kingston, Ontario, Canada. Electronic address: salmosnino@rea.ca.
authors.forename: Sivan
authors.initials: S
authors.lastname: Almosnino
authors.affiliation: Department of Mechanical and Materials Engineering, Queen's University, Kingston, Ontario, Canada; Human Mobility Research Centre, Syl & Molly Apps Medical Research Centre, Kingston General Hospital, Kingston, Ontario, Canada.
authors.forename: Scott C E
authors.initials: SC
authors.lastname: Brandon
authors.affiliation: Clinical Research Centre, Kingston General Hospital, Kingston, ON, Canada.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Day
authors.affiliation: School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada; Human Mobility Research Centre, Syl & Molly Apps Medical Research Centre, Kingston General Hospital, Kingston, Ontario, Canada.
authors.forename: Joan M
authors.initials: JM
authors.lastname: Stevenson
authors.affiliation: School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada; Department of Physical Therapy, The Stanley Steyer School of Health Professions, Sackler Faculty of Medicine, Tel Aviv University, Israel.
authors.forename: Zeevi
authors.initials: Z
authors.lastname: Dvir
authors.affiliation: Division of Orthopaedic Surgery, School of Medicine, Queen's University & Kingston General Hospital, Kingston, Ontario, Canada; Human Mobility Research Centre, Syl & Molly Apps Medical Research Centre, Kingston General Hospital, Kingston, Ontario, Canada.
authors.forename: Davide D
authors.initials: DD
authors.lastname: Bardana
mesh_terms: D000328:Adult; D016118:Anterior Cruciate Ligament / Q000503:physiopathology; D000070598:Anterior Cruciate Ligament Injuries; D005081:Exercise Therapy; D005260:Female; D006801:Humans; D007717:Knee / Q000502:physiology* / Q000503:physiopathology*; D007718:Knee Injuries / Q000503:physiopathology* / Q000534:rehabilitation; D016015:Logistic Models; D008297:Male; D009068:Movement / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology / Q000503:physiopathology; D025341:Principal Component Analysis; D012372:ROC Curve; D016059:Range of Motion, Articular / Q000502:physiology
keywords: Anterior cruciate ligament; Classification; Diagnostics; Isokinetic dynamometry; Knee; Sensitivity; Specificity; Strength