Affiliations: [a] Department of Rehabilitation, Nostra Senyora de
Meritxell Hospital, Principality of Andorra | [b] Servei d'Estadística Aplicada, Universitat
Autónoma de Barcelona, Spain | [c] Orthopaedic and Trauma Unit, Nostra Senyora de
Meritxell Hospital, Principality of Andorra
Correspondence:
[*]
Corresponding author: María Laura Tutté Maldonado,
Department of Rehabilitation, British Hospital and Banco de Seguros del Estado,
Av. Colombes 1485, Montevideo 11400, Uruguay. Tel.: +598 26137698; E-mail: dra.tutte@gmail.com.
Abstract: BACKGROUND: Osteoarthritis (OA) is the most prevalent joint
pathology and an important cause of disability among people over 65 years of
age. Following total knee replacement (TKR), which may be the only curative
intervention, function is mainly affected by quadriceps weakness whose extent
can accurately be assessed using isokinetic dynamometry. AIM: To evaluate the association between the Western Ontario and McMaster Universities
Arthritis Index (WOMAC) and the Hospital for Special Surgery Score (HSS) scores
and knee muscle isokinetic strength and fatigue findings in TKR patients 2–5
years postoperatively as well as assess the reproducibility and validity of the
isokinetic test findings in this cohort. DESIGN: Twenty-four women who underwent TKR filled in the WOMAC and HSS questionnaires.
The isokinetic test was carried out at 120 and 180°/s in concentric flexion/extension.
The maximal isokinetic strength was evaluated as the peak torque (PT). Isokinetic
fatigue was measured using the fatigue index and calculated based on 40
repetitions at 120°/s. The same protocol was performed 7 days apart.
Test-retest reproducibility was analyzed using intraclass correlation
coefficient (ICC), the standard error of measurement (SEM) and Bland Altman
plots. HSS and WOMAC internal consistency was tested with Cronbach's alpha;
questionnaire validity and correlations were obtained using Spearman's rho. RESULTS: The HSS Function sub-score was significantly correlated with
quadriceps PT but not with fatigue isokinetic scores. Excellent reproducibility
was indicated for all outcome measures, with the exception of the HSS Knee
subscore and the fatigue index. CONCLUSIONS: Isokinetic dynamometry of the quadriceps can provide objective
and useful information regarding the functional status of patients following
TKR due to OA of the knee.
