Correlation in the Coronal Angle between Knee and Hindfoot Was Observed in Patients with Rheumatoid Arthritis Unless Talocrural Joint Was Destroyed.

Kohei Nishitani,Masao Tanaka,Tsuneyo Mimori,Hiromu Ito,Motomu Hashimoto,Yoshiharu Shimozono,Masayuki Azukizawa,Moritoshi Furu,Shuichi Matsuda

doi:10.1155/2017/4051706

Abstract

The purpose of this study is to investigate the compensatory correlation between knee and hindfoot in patients with rheumatoid arthritis (RA). This cross-sectional study included 218 patients (407 lower extremities). Radiographs of the hindfoot and full-length posteroanterior hip-to-calcaneus standing radiographs were evaluated. The destruction of the hindfoot was evaluated using the Larsen grading system. The coronal angular deformity of the knee and hindfoot was evaluated by the femorotibial angle (FTA) and the angle between the tibial shaft and the entire hindfoot (tibiohindfoot angle, THFA). The correlation between FTA and THFA was determined by Pearson's coefficient. For all patients, FTA correlated to THFA (R = 0.28, p < 0.001). The correlation was observed as long as the talocrural joint was preserved (Larsen grade ≤ 2), even if the subtalar joint had been destroyed (Larsen grade ≥ 3). However, the correlation was not observed when the talocrural joint was destroyed (Larsen grade ≥ 3, R = −0.02, p = 0.94). The pain in the hindfoot did not correlate with FTA or THFA. In conclusion, a compensatory deformity of the hindfoot against the deformity of the knee was observed in RA, and the correlation was lost when talocrural joint was destroyed.

Highlights

In the coronal alignment of the lower limb, patients with osteoarthritis (OA) exhibit a collaborative correlation of the angle of the knee and the hindfoot [1,2,3,4]
tibiohindfoot angle (THFA) correlated with femorotibial angle (FTA) only when the talocrural joint was preserved
Though the correlation was not strong, THFA was significantly correlated with FTA (R = 0.28, p < 0.001) in the analysis of the all legs in the cohort (n = 407), regardless of deformity of the hindfoot (Figure 2(a))

Summary

Introduction

In the coronal alignment of the lower limb, patients with osteoarthritis (OA) exhibit a collaborative correlation of the angle of the knee and the hindfoot [1,2,3,4]. The hindfoot is often affected in patients with RA, and the prevalence of the subtalar joint is reported as 29% to 32% [9, 10]. In terms of the coronal deformity, the valgus deformity of the hindfoot is reported in 25% of the RA patients [11]. In a recent ultrasonic study, synovitis occurred more frequently compared with the radiographic change in hindfoot and the prevalence of talocrural, subtalar, and talonavicular synovitis is 76%, 71%, and 59%, respectively [12]. The BioMed Research International talocrural joint is less affected in patients with RA and the change in the subtalar joint proceeds to the talocrural joint in many cases [13]

Objectives

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Results