Non-operative treatment of unicompartmental osteoarthritis of the knee: a prospective randomized trial with two different braces-ankle-foot orthosis versus knee unloader brace

Abstract

Background: The use of an unloader brace is a non-surgical treatment option for patients with medial osteoarthritis (OA). However, many patients do not adhere to brace treatment, because of skin irritation due to the pads at the level of the joint space and bad fit. A new concept to unload the medial compartment of the knee is a foot ankle brace with a lever arm pressing the thigh in valgus. The aim of this prospective randomized trial was to examine the outcomes of patients with medial OA after treatment with a conventional knee unloader brace (Unloader One^®) and the new foot ankle orthosis (Agilium FreeStep^®).

Methods: For this multicenter trial, 160 patients (> 35 years) with medial OA were randomly allocated to treatment with a conventional knee unloader brace (Unloader One^®) or treatment with the new knee OA ankle brace (Agilium FreeStep^®). The primary outcome measure was pain (numerical analog scale) at baseline (T0), 8 weeks (T1), and 6 months (T2). Secondary outcome measures were knee function (Knee Injury and Osteoarthritis Outcome Score, KOOS), side effects, additional interventions, and compliance.

Results: In both groups, walking pain improved between T0 and T1 and also between T0 and T2 without a significant group difference. For pain at sports, both groups showed a significant improvement between T0 and T2 without a significant group difference. The KOOS subscales symptoms, pain, activity, sport, and quality of life increased significantly in both treatment groups without any significant group differences at T 0, T1, and T2. There was also no significant group difference in additional interventions and weekly or daily brace use. In the Agilium FreeStep^® group (23.5%), significantly less patients reported bruises in contrast to the Unloader One^® group (66.7%).

Discussion: The results of this clinical trial show that the foot ankle brace is as effective as a conventional knee unloader brace for the treatment of medial knee OA with regard to clinical outcome. The rate of side effects such as bruises was significantly lower in the Agilium FreeStep^® group.

Trial registration: DRKS00009215, 13.8.2015.

Keywords: Biomechanical interventions; Biomechanics; Knee pain; Non-surgical OA interventions; Varus deformity; Varus malalignment.