Effect of a Realigning Brace on Tibiofemoral Contact Stress

Abstract

Objective. To determine the degree to which focally elevated tibiofemoral joint contact stress is reduced by using a frontal plane realigning brace. Methods. Fifteen volunteers (9 women) with unicompartmental tibiofemoral osteoarthritis underwent weight-bearing radiographic imaging at 15-208 and 5-108 of knee flexion with and without an UnloaderOne knee brace. Discrete element analysis was used to estimate compartment-specific contact stress distributions. Paired t-tests were used to assess the differences in mean contact stress and contact stress distributions, comparing the braced and unbraced conditions. Results. The mean 6 SD age was 56.1 6 6.4 years and body mass index was 28.4 6 4.5 kg/m 2 . Twelve of 15 participants were fit with braces set to unload the medial compartment. For the 15-208 condition, the mean contact stress in the compartment of interest did not significantly change (0.08 6 0.35 MPa; P 5 0.410). Also at 5-108 flexion, the mean contact stress in the compartment of interest did not significantly change with use of the brace (0.24 6 0.45 MPa; P 5 0.175). Conclusion. This is the first study of the effects of a frontal plane realignment brace on in vivo articular contact stress in native human knees. Using the off-the-shelf brace tested, there were no changes in compartmental tibiofemoral contact stress distributions at either 15-208 or 5-108 of knee flexion, revealing no redistribution of contact stress away from the compartment of interest. These findings indicate that the brace that was studied was ineffective for redistributing tibiofemoral contact stress. Further research is necessary to determine whether double-upright or customized frontal plane braces are effective in redistributing compartmental articular contact stress.

Osteoarthritis year in review 2016: mechanics

“…Obviously the state of tissue structure and biology alter the effects of biomechanics ( Fig. 1) 17,65 .…”

Biomechanical Effect of Valgus Knee Braces on the Treatment of Medial Gonarthrosis: A Systematic Review

“…Two studies confirmed that the brace significantly reduced the peak contact stress in the medial compartment while increased in the lateral compartment [ 51 , 55 ]. One study [ 53 ] showed that the mean contact stress and contact area of the medial compartment were not changed when the knee joint was at 5-10° and 15-20° flexion states.…”

Longitudinal Relationship Between Tibiofemoral Contact Stress at Baseline and Worsening of Knee Pain Over 84 Months in the Multicenter Osteoarthritis Study

“…15 The present study indicates that articular contact stress, which accounts for both bone structure and cartilage morphology, is associated with 84-mo worsening of knee pain. In addition, contact stress estimates can provide clinicians with evidence to select appropriate treatments for reducing articular contact stress in the knee joint, [35][36][37] as well as improving knee symptoms, physical function, and potentially delaying or preventing the progression of knee OA. Laterally wedged insoles are commonly prescribed to shift loading from the medial to lateral compartments in patients with medial knee OA.…”

“…6,41 Contact stress estimates could help both identify patients with early knee OA most likely to benefit from these conservative treatments as well as to evaluate the biomechanical effects. Segal et al 37 used DEA-based contact stress estimates to assess the biomechanical effect of a single-upright brace for the realignment of the tibiofemoral joint in participants with unicompartmental tibiofemoral OA.…”