Thrust during ambulation and the progression of knee osteoarthritis

Abstract

Objective. To determine whether the presence of varus thrust at baseline increases the risk of progression of medial tibiofemoral osteoarthritis (OA), whether knees with thrust have a greater adduction moment, whether thrust has any additional impact on top of static varus, and whether thrust is associated with poor physical function outcome.Methods. Two hundred thirty-seven patients with knee OA (definite osteophytes and symptoms) underwent baseline gait observation to assess varus thrust and full-limb radiography to assess alignment. Sixtyfour of these 237 patients also underwent quantitative gait analysis to determine the maximum knee adduction moment. Two hundred thirty patients (97%) returned for followup at 18 months. At baseline and 18 months, the 230 participants had semiflexed, fluoroscopically confirmed knee radiographs (with progression defined as worsening of medial joint space grade); self-reported and performance-based measures of function were also assessed. Logistic regression with generalized estimating equations was used to estimate odds ratios (ORs) for medial OA progression, after excluding knees that were not at risk for progression.Results. Varus thrust was present in 67 of 401 knees. Thrust increased 4-fold (age-, sex-, body mass index-, and pain-adjusted OR 3.96, 95% confidence interval [95% CI] 2.11-7.43) the odds of medial progression, with some reduction after further adjustment for varus alignment severity. In varus-aligned knees, thrust increased the odds of OA progression 3-fold (adjusted OR 3.17, 95% CI 1.60-6.31). In the gait substudy, the adduction moment was greater in knees with a thrust compared with knees without a thrust. Having a thrust in both knees versus neither knee was associated with a 2-fold increase in the OR for poor physical function outcome (P not significant).Conclusion. Varus thrust is a potent risk factor, identifiable by simple gait observation, for disease progression in the medial compartment, the most common site of OA involvement at the knee. Varus thrust may also predict poor physical function outcome. Varus thrust increased the odds of progression among varusaligned knees considered separately, suggesting that knees with a thrust are a subset of varus-aligned knees at particularly high risk for progression of OA.

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

“…Our analysis included a combination of a static measurement (medial JS) indicative of knee structure, and a dynamic measurement (peak knee adduction angle) indicative of knee function. The peak knee adduction angle during gait corresponds to the 'varus thrust', sudden lateral bowing of the knee during the diagonal weight shift in patients with medial knee OA [12]. The peak knee adduction angle is not used routinely in clinical practice, although it has been recommended as an important clinical index for knee OA [45]; our data support this recommendation.…”

Prospective study on the effects of orthotic treatment for medial knee osteoarthritis in Chinese patients: clinical outcome and gait analysis

“…4 Apart from static lower limb alignment, dynamic varus thrust during the gait cycle is also independently associated with osteoarthritis progression in the knee. 5 Knee adduction moment (KAM) is an indirect means to assess varus thrust during the gait cycle. Previous studies have proven the validity of KAM for prediction of clinical and radiological osteoarthritis progression.…”

Role of High Tibial Osteotomy in Chronic Posterior Cruciate Ligament and Posterolateral Corner Knee Instability

“…In chronic lesions, posterolateral structures become overused with a further decrease in function. This phenomenon is increased during gait because all the weight bears on a limb (Chang et al, 2004;Miller et al, 2002;Noyes et al, 2006) (Fig. 1).…”

“…1) (see the Biomechanics section). Gait analysis is important to detect PLC associated lesions because, in some cases, patients with hyperextension varus thrust have poorer results than patients with normal gait (Chang et al, 2004;Miller et al, 2002;Noyes et al, 1996).…”