A comparison between laterally wedged insoles and ankle-foot orthoses for the treatment of medial osteoarthritis of the knee: A randomized cross-over trial

Abstract

Objective: To compare biomechanical and clinical outcome of laterally wedged insoles (LWI) and an ankle-foot orthosis (AFO) in patients with medial knee osteoarthritis. Design: Single-centre, block-randomized, cross-over controlled trial. Setting: Outpatient clinic. Subjects: About 39 patients with symptomatic medial knee osteoarthritis. Interventions: Patients started with either LWI or AFO, determined randomly, and six weeks later changed to the alternative. Main measures: Change in the 1st maximum of external knee adduction moment (eKAM) was assessed with gait analysis. Additional outcomes were other kinetic and kinematic changes and the patient-reported outcomes EQ-5D-5L, Oxford Knee Score (OKS), American Knee Society Clinical Rating System (AKSS), Hannover Functional Ability Questionnaire – Osteoarthritis and knee pain. Results: Mean age (SD) of the study population was 58 (8) years, mean BMI 30 (5). Both aids significantly improved OKS (LWI P = 0.003, AFO P = 0.001), AKSS Knee Score (LWI P = 0.01, AFO P = 0.004) and EQ-5D-5L Index (LWI P = 0.001, AFO P = 0.002). AFO reduced the 1st maximum of eKAM by 18% ( P < 0.001). The LWI reduced both maxima by 6% ( P = 0.02, P = 0.03). Both AFO and LWI reduced the knee adduction angular impulse (KAAI) by 11% ( P < 0.001) and 5% ( P = 0.05) respectively. The eKAM (1st maximum) and KAAI reduction was significantly larger with AFO than with LWI ( P = 0.001, P = 0.004). Conclusions: AFO reduces medial knee load more than LWI. Nevertheless, no clinical superiority of either of the two aids could be shown.

Varus Knee Limits Pain Relief Effects of Laterally Wedged Insoles and Ankle-Foot Orthoses in Medial Knee Osteoarthritis

“…Although the AFO's influence on eKAM was significantly higher than the LWI's in our own biomechanical evaluations (25), the MAD cut-off is only slightly higher for AFO than for LWI. In the isolated consideration of the MA and pain, the AFO does not appear to be superior to the LWI, but rather equal.…”

“…This is a secondary analysis carried out on participants of a study comparing AFO and LWI in patients with medial osteoarthritis of the knee (25), hypothesizing that the MAD has an influence on the clinical response to LWI and AFO. Randomized, monocentric, clinically prospective cross-over study conducted at Heidelberg University Hospital, Clinic for Orthopaedics and Trauma Surgery.…”

“…The design of the original study did not mainly target the evaluation of the MAD, but was rather planned to evaluate the biomechanical parameter eKAM. The sample size calculation was also based on the biomechanical outcome (25), while the study may be under-powered for the evaluation of clinical outcomes. Since the current evaluation of the MAD could only be carried out in a significantly smaller proportion (72%) of the participants, the data should not be overinterpreted.…”

Evaluation of the Effect of Knee Unloader Orthoses, Lateral Wedge Insoles, and Ankle Foot Orthoses on Pain, Function, and Knee Adduction Moment in Subjects with Medial Compartment Knee Osteoarthritis: A Literature Review

“…In comparative studies of two groups, knee brace and insoles, which had a longer follow-up time, knee brace was reported to have a greater effect on pain reduction in the knee than insoles 47,52–54 . In another comparative study of two groups, LW and AFO, no clinical superiority of either of the two aids could be shown 60 . Only the studies with immediate effect and short follow-up period reported the same effect on pain reduction in both knee brace and insole groups 26,53 .…”

Osteoarthritis year in review 2021: mechanics

“…One study compared 12 weeks of lateral wedge insole wear to neutral insoles and found lateral wedge insoles were no more effective than neutral insoles at reducing KAM and KAM impulse 90 . A second RCT compared 6 weeks of insole wear to an ankle foot orthosis, and found lateral wedge insoles to be less effective than the ankle foot orthosis at reducing KAM and KAM impulse, though the between-group differences were of doubtful clinical relevance 91 .…”