Mechanical effectiveness of lateral foot wedging in medial knee osteoarthritis after 1 year of wear

Abstract

Purpose The use of lateral foot wedging in the management of medial knee osteoarthritis is under scrutiny. Interestingly, there have been minimal efforts to evaluate biomechanical effectiveness with long term use. Therefore, we aimed to evaluate dynamic knee loading (assessed using the knee adduction moment) and other secondary gait parameters in patients with medial knee osteoarthritis wearing lateral foot wedging at a baseline visit and after 1 year of wear. Methods 3-dimensional gait data were captured in an intervention group of 19 patients with symptomatic medial knee osteoarthritis wearing their prescribed laterally wedged foot orthoses at 0 and 12 months. Wedge amounts were prescribed based on symptom response to a step-down test. A control group of 19 patients wearing prescribed neutral orthoses were also captured at 0 and 12 months. The gait of the intervention group wearing neutral orthoses was additionally captured. Walking speed and shoes were controlled. Analyses of variance were conducted to examine for group-by-time (between the groups in their prescribed orthoses) and condition-by-time (within the intervention group) interactions, main effects, and simple effects. Results We observed increased knee adduction moments and frontal plane motion over time in the control group but not the intervention group. Further, within the intervention group, the mechanical effectiveness of the lateral wedging did not decrease. Conclusions In patients with medial knee osteoarthritis, the effects of lateral foot wedging on pathomechanics associated with medial knee osteoarthritis were favorable and sustained over time.

Lateral Wedge Insoles for Reducing Biomechanical Risk Factors for Medial Knee Osteoarthritis Progression: A Systematic Review and Meta‐Analysis

“…Numerous RCTs on lateral wedge insoles have been published, but report only pain outcomes (19), and data on their acquired or long-term biomechanical effects are scarce (31). We assessed for the presence of publication bias by using funnel plots and formal testing, which revealed weak evidence for an effect, strengthening the inferences from this review.…”

“…All but 4 studies were withinsubjects repeated-measures designs, with the remaining being randomized trials (30)(31)(32)(33). Four studies reported the use of the ACR criteria (31,(34)(35)(36), with 10 stating cutoffs regarding the severity of knee pain (13,14,21,31,32,34,(36)(37)(38)(39), most commonly .3 of 10 on a visual analog scale (13,14,21,31,32,34,37). This definition varied across studies according to the activity, with pain recalled during walking (29,38), walking 2 blocks and/or climbing stairs (36), weight-bearing activities (37), and on most days of the past month (21,32,39).…”

“…All studies included radiographic assessment of tibiofemoral OA. This was most commonly defined as Kellgren/Lawrence grade 2 and above (13,14,21,29,31,32,34,37,38,40). Presence of medial joint space narrowing greater than lateral (13,32, 29,32,33,35,36,38,39) and/or varus knee alignment (13,30, 36,40,41) were used to limit participants to those with medial tibiofemoral OA.…”

“…The most common insole inclination angle was 5 degrees (13,21,29,32,33,36,38,39,43), with insole angles ranging from 4 (40) to 11 degrees (34). The presence of a concomitant medial arch support was common with 4 studies modifying generic insoles (14,31,37,43) and 3 used a bespoke design (29,33,38). Fourteen studies prescribed the same insole to all participants, with the remaining 4 using a customized amount based on comfort and/or pain level (14,31,35,37).…”

“…Fourteen studies prescribed the same insole to all participants, with the remaining 4 using a customized amount based on comfort and/or pain level (14,31,35,37). A flat insole was the comparison condition in 4 studies (14,31,34,37), 7 studies used participants' own footwear (13,21,30,32,36,40,43), 5 studies used standardized footwear (29,33,35,39,42), 1 study used both a flat insole and participants' own footwear (39), and 1 study did not report the type of footwear (41). Walking speed was either controlled across conditions within a threshold of each participants' preferred speed (13,14,21,31,32,37), (43).…”