Effect of Laterally Wedged Foot Orthoses on Rearfoot and Hip Mechanics in Patients with Medial Knee Osteoarthritis

Abstract

The purpose of this study was to examine the effects of laterally wedged foot orthotic devices, used to treat knee osteoarthritis, on frontal plane mechanics at the rearfoot and hip during walking. Thirty individuals with diagnosed medial knee osteoarthritis were recruited for this study. Three dimensional kinematics and kinetics were recorded as the subjects walked in the laboratory at an intentional walking speed. Peak eversion, eversion excursion and peak eversion moment were increased while the peak knee adduction moment was reduced in the laterally wedged orthotic condition compared to the no wedge condition. In contrast, no changes were observed in the variables of interest at the hip. There was no significant relationship between the change in the peak frontal plane moment at the rearfoot and change in the peak frontal plane moment at the knee or hip as a result of the lateral wedge. Laterally wedged foot orthotic devices, used to treat knee osteoarthritis, do not influence hip mechanics. However, they do result in increased rearfoot eversion and inversion moment. Therefore, a full medical screen of the foot should occur before laterally wedged foot orthotic devices are prescribed as a treatment for knee osteoarthritis.

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

“…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.…”

“…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).…”

Are Joint Structure and Function Related to Medial Knee OA Pain? A Pilot Study

“…The treatment goal in varus knee OA, by means of surgical (eg, high tibial osteotomy) [16,22,61] and nonsurgical methods (eg, wedging foot orthoses, unloading knee braces) [10,42,58], is to reduce deviation of the mechanical axis of the lower extremity from the knee joint center. However, the 'mechanical axis' is a static 2-D radiographic measurement that varies with foot position [32] and weightbearing status (eg, single versus doublelimb support) [70], and it might not always correlate with complex 3-D loading or dynamic function of the knee [2,28,40].…”