Effect of posterior tibial tendon dysfunction on unipedal standing balance test.

Abstract

Foot pain and diminished functional capacity are characteristics of tibialis posterior tendon dysfunction (TPTD). This study tested the hypotheses that women with TPTD would have impaired performance of a unipedal standing balance test (USBT) and that balance performance would be related to the number of single limb heel raises (SLHR). Thirty-nine middle-aged women, 19 with early stage TPTD (stage I and II), were instructed to perform 2 tasks; a USBT and repeated SLHR. Balance success was defined as a 10-second stance. For those who were successful, center of pressure (COP) data in anterior-posterior (AP) and medial-lateral (ML) directions were recorded as a measure of postural sway. SLHR performance was divided into 3 bins (≤2; 3-9 and > 10 repetitions). The between-balance success on performing the SLHR test was analyzed using the Fisher's exact test (2 × 3). Independent t tests were used to compare between-group differences in postural sway. Relationship of postural sway to the number of heel raises was assessed using Spearman's rho. The success rate of the USBT was significantly lower in women with TPTD than the controls (47% vs 85%, P = .041). In addition, women with TPTD who completed the USBT exhibited increased AP COP displacement (14.0 ± 7.4 vs 8.4 ± 1.3 mm, P = .008), and a strong trend of increased ML COP displacement (8.3 ± 4.5 vs 6.1 ± 1.2 mm, P = .050). The success rate of USBT was correlated with the number of SLHR (P = .01). The AP and ML COP displacement were correlated with SLHR (r = -.538 and .495), respectively. Women with TPTD have difficulty in performing the USBT. Performance of the USBT and SLHR are highly correlated and predictive of each other. A unipedal balance test may be used as a proxy TPTD assessment tool to the heel raising test when pain prevents performance. Level III, case control study.