Effect of foot insoles on anterior-knee-pain and hip-kinematics: the same shoe does not fit every foot - a systematised literature review.

Background: Anterior knee pain (AKP) or patella-femoral pain syndrome is a common problem amongst active population of any age group. It is characterised by non-specific and diffuse pain of insidious origin in the anterior and/or retro patellar areas of knee. This has significant impact on activities of daily living such as walking, ascending-descending stairs, jogging, running, and squatting which often lead to mental health problems. The cause for AKP is unknown. Abnormal patellar tracking resulting from neuromuscular and biomechanical changes is believed to be a common cause of this problem. Treatment options includes in-soles, deep tissue massage, strengthening, tapping, mobilization, dry needling, and acupuncture. Biomechanically there is strong relationship between hip, knee, and foot. In-soles are useful to alter the foot biomechanics and hip kinematics that helps to relieve the knee pain. Existing literatures on this topic focused on the effectiveness of foot insoles on running and walking but none of the studies evaluated the effectiveness of foot insoles particularly in descending stairs and single leg squatting activities. Therefore, this study was needed to address the gaps in literature and to determines the effectiveness of insoles in AKP.

Purpose: The purpose of this study was to evaluate the effectiveness of foot insoles on knee pain and hip kinematics during stair descent and/or single-leg squat activities in individuals with AKP. The aim of this review was to synthesis the findings of studies evaluating the effectiveness of foot insoles on AKP.
Methods: A systematised literature search was conducted in databases including CINAHL, SPORTDiscus, AMED, PubMed and MEDLINE using a comprehensive search strategy. Search terms were developed using PICO framework including MeSH terms. Additional search was conducted in Google scholar. Search results were reported using PRISMA guidelines. Pre-established inclusion and exclusion criteria applied to identify the studies and a total of 7 studies were included in this review. Methodological quality of included studies was conducted using relevant critical appraisal tool such as CASP checklist for RCT and cohort studies, and the Cochrane library-derived checklist for cross-over studies. The pooled data showed heterogeneity and therefore, a narrative synthesis approach was adapted to report the findings of this review.

Results: Among the 7 includes studies two were RCTs, one cohort study and 4 cross-over studies. Six studies evaluated the effectiveness of insoles on pain and three studies evaluated the effect of insole on hip adduction movement. Four studies showed statistically significant effectiveness of insoles in relieving knee pain and two studies showed statistically significant improvement in hip kinematics.

Conclusion(s): Findings showed that foot insoles were useful in reducing the intensity of anterior knee pain and improving hip adduction movement. However, there were several methodological shortcomings in the included studies and this review provided a moderate and low of evidence for the effectiveness of foot insoles on anterior knee pain and hip kinematics respectively.

Implications: The changes in foot posture impacts on the knee and hip biomechanics. Hence, foot insoles are useful and cost effective for patients with knee and hip problems.