Posture of the foot: Don't keep it out of sight, out of mind in knee osteoarthritis.

BACKGROUND

There are many contributors of knee osteoarthritis including the postural abnormalities of the adjacent joints. The relationship between foot posture and the clinical-radiological parameters of knee osteoarthritis is poorly understood.

RESEARCH QUESTION: Is foot posture related to the clinical and radiological parameters in patients with knee osteoarthritis?

METHODS

Patients diagnosed with primary clinical and radiographic medial tibiofemoral knee osteoarthritis were included in the study. Anteroposterior knee radiographs were staged by using the Kellgren-Lawrence grading system. Computer-based measurements of the medial joint space width (mJSW), condylar angle, anatomical axis angle, tibial plateau angle and condylar plateau angle were performed on digital anteroposterior knee radiographs. The Western Ontario and Mc Master University Osteoarthritis Index (WOMAC) questionnaire was used to assess pain and the functional status of the patients. Foot posture was assessed by the Foot Posture Index (FPI) system and feet were categorized into three (pronated, neutral and supinated).

RESULTS

The study included 150 patients (150 knees and feet at one side) with a mean age of 61.2 ± 10.1 years. In terms of foot posture groups; percentages for supination, neutral and pronation were 22.66%, 68.66% and 8.66%, respectively. In the group with supinated FPI; WOMAC total score, pain and function subscale scores were higher (p < 0.001), mJSW was narrowed (p = 0.038) and the condylar plateau angle was increased (p = 0.009). In the FPI pronation group; anatomic axis angle values were found to change in the varus direction (p = 0.012).

SIGNIFICANCE: The potential postural dysfunction of the foot should be taken into consideration during the assessment and/or management of a patient with knee osteoarthritis.