Elsevier

Gait & Posture

Volume 66, October 2018, Pages 130-134
Gait & Posture

Full length article
Posture of the foot: Don’t keep it out of sight, out of mind in knee osteoarthritis

https://doi.org/10.1016/j.gaitpost.2018.08.036Get rights and content

Highlights

  • Radiologic severity of knee OA is associated with supinated foot posture.

  • Varus alignment in knee OA is related to pronated foot posture.

  • Clinical severity in knee OA is associated with supinated foot posture.

Abstract

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.

Introduction

Kneeosteoarthritis (OA) is one of the representatives of the multi-causation disease model. It is not only contributed by the biochemical factors in the human body, but also related to the mechanical properties of the adjacent joints including the hip and the ankle [1].

The biomechanical factors mostly work by altering the knee adduction moment, which forces the knee to adduction position during gait. Adduction moment is the leading factor that affects the mediolateral force distribution inside the knee joint [2,3]. Theoretically, increase in the adduction moment can give a rise to medial tibiofemoral OA, can also make contribution to the radiologic and clinical progression of knee OA [4,5]. Along the kinetic chain of the lower limb, the adjacent joints including the ankle work together with the knee joint in order to properly align the extremity. Therefore, postural deformities of the ankle/foot might serve as potential determinants of adduction moment, thus knee OA. The mechanism for the impact of foot posture on knee adduction moment might be explained partially with the change in the centre of ground reaction force. Particular foot alignments are likely to exert greater knee adduction moments, whilst some certain types such as increased rearfoot eversion, rearfoot internal rotation and forefoot inversion can reduce the knee adduction moment. Differences in foot alignments make differences on the ground reaction force vector. The longer the perpendicular distance of the vector from the knee joint, the greater the adduction moment would be [6]. Foot posture in knee OA/knee pain was studied by a number of researchers in the literature [[7], [8], [9], [10]]. Gross et al. [8], in their cross-sectional study, highlighted the association of planus arch deformity with the higher frequency of knee pain and medial tibiofemoral cartilage damage in older adults. On the other hand, Levinger and colleagues [7] found that patients with medial tibiofemoral OA had higher frequency of pronated foot than 28 asymptomatic age-matched controls.

All in all, there are several studies evaluating the association of foot posture with the frequency of knee OA, along with the parameters such as knee pain and cartilage damage. However, the potential interaction of foot posture with the clinical and the radiological parameters in patients with knee OA is scarce [11]. Taken as a whole, a comprehensive look identifying the relation of foot posture with the objective clinical measures of knee OA, as well as with the radiologic indicators of knee loading/alignment seems necessary.

In the light of the above-mentioned knowledge, the present study aimed to evaluate the relation of foot posture with i) the radiologic severity of knee OA, ii) the varus alignment of the knee and iii) the clinical severity in patients with medial tibiofemoral knee OA.

Section snippets

Patients

The study included patients with symptomatic and radiographic signs of knee OA according to the American Collage of Rheumatology Criteria for knee OA [12]. The exclusion criteria were as follows: i) presence of any known inflammatory rheumatic disease/arthritis, ii) concomitant neurologic diseases including stroke, spinal cord injury, multiple sclerosis, polyneuropathy and drop foot, iii) presence of lower limb length discrepancy/deformity, iv) history of lower extremity fracture/surgery, v)

Results

The study included 150 patients (150 knees and feet at one side) with symptomatic and radiographic knee OA. Characteristics of the study population were summarized in Table 1. Accordingly, mean values for age, BMI and symptom duration of the study participants were 61.2 ± 10.1 years, 33.7 ± 5.3 kg/m2 and 6.0 ± 4.1 months, respectively.

Of the 150 feet evaluated; 34 (22.66%), 103 (68.66%) and 13 (8.66%) were at supinated (FPI < 0), neutral (FPI = 0 to +5) and pronated (FPI ≥ +6) posture,

Discussion

The present study has two emerging findings to discuss:

  • i)

    Both the radiologic and the clinical severity of knee OA is associated with supinated foot posture.

  • ii)

    Varus alignment in knee OA is related to pronated foot posture.

Supination/pronation of the foot is a complex entity. Supination of the foot is a combination of three movements: inversion in the frontal plane, plantar flexion in the sagittal plane and adduction in the horizontal plane. On the other hand, pronation of the foot refers to the

Conflicts of interest

The authors declare no conflicts of interest.

Acknowledgement

None to declare.

References (28)

  • O.D. Schipplein et al.

    Interaction between active and passive knee stabilizers during level walking

    J. Orthop. Res.

    (1991)
  • T. Miyazaki et al.

    Dynamic load at baseline can predict radiographic disease progression in medial compartment knee

    Ann. Rheum. Dis.

    (2002)
  • P. Levinger et al.

    Relationship between foot function and medial knee joint loading in people with medial compartment knee osteoarthritis

    J. Foot Ankle Res.

    (2013)
  • P. Levinger et al.

    Foot posture in people with medial compartment knee osteoarthritis

    J. Foot Ankle Res.

    (2010)
  • Cited by (20)

    • Nomogram model based on radiomics signatures and age to assist in the diagnosis of knee osteoarthritis

      2023, Experimental Gerontology
      Citation Excerpt :

      Moreover, the relationship between foot posture and the clinical-radiological parameters of KOA is very close. The potential postural dysfunction of the foot needs to be taken into consideration during the assessment or management of patients with KOA (Al-Bayati et al., 2018). Knee alignment was not separately included in the radiomics analysis in our study because the full-leg standing anteroposterior radiographs were not collected.

    • The effect of modifying foot progression angle on the knee loading parameters in healthy participants with different static foot postures

      2020, Gait and Posture
      Citation Excerpt :

      The KAM1 was reduced only in the neutral foot posture group during the toe-in condition, which was consistent with the results of previous studies that toe-in gait reduced the first peak KAM [37]. In a study by Al-Bayati Z et al. [28], of the 150 feet evaluated, 68.66 % of patients with knee OA had a neutral foot posture. Patients with a neutral foot type would obtain more biomechanical benefit from toe-in gait than patients with other foot types.

    • Ultrasound evaluation of the quadriceps muscles in pronated foot posture

      2019, Foot
      Citation Excerpt :

      It has been hypothesized that the alteration in the afferent information to the central nervous system, in turn, had an effect on the efferent information to the muscles resulting in inhibition of muscle kinetic response [17,18] and consequently muscle atrophy [19]. Despite several studies that have investigated the association between foot posture and knee joint injuries (Gross et al.; [9,11,12] limited number of studies have assessed the quadriceps muscle size in knee [20,21,22] injuries. The muscle thickness, as a parameter of muscle mass, is associated with muscle strength and is defined as a distance between superficial and deep fascia of a muscle using musculoskeletal ultrasound imaging (USI) [23,24].

    View all citing articles on Scopus
    View full text