Inverted
posture
‘A Rearfoot
good fit?’
sample included 68 patients (47.6% of the
initial cohort) at 12 months follow-up period.
Baseline characteristics were compared
between included and excluded patients, and
no significant differences were found between
the two groups in terms of demographic
characteristics and radiographic disease
severity at baseline period (data not shown). Of
the 68 patients who completed the study (age
56–90 years; 75.0% female), 48 (70.6%) had mild
diseases with K/L grade=2 in their index knee
(Table 1). Thirty-eight (55.9%) of these patients
had PFOA.
Table 2 shows the comparison of calcaneus
inverted angle and calcaneus alignment in
knees with and without PFOA. Calcaneus
inverted angle in patients with coexisting PFOA
was higher than those with isolated TFOA
(1.046±5.053 vs. -2.245±5.648; p=0.014). Patients
with coexisting PFOA on average had an
inverted calcaneus 3.1° greater than those with
isolated medial TFOA after adjusting for age,
sex, BMI, TF joint K/L grade, corrected AAA,
presence of varus thrust, and knee flexion ROM
(p=0.047). Patients with coexisting PFOA had a
higher prevalence of inverted calcaneus (15.4%
vs. 6.9%) and lower prevalence of everted
calcaneus (12.8% vs. 27.6%), although these
calcaneus alignments did not significantly differ
between the two groups (p=0.218).
Table 2: Comparison of calcaneus inverted angle and calcaneus alignment in knees with and without PFOA (n = 68)
Variables Coexisting Any
PFOA (n = 38
knees) Isolated TFOA
(n = 30 knees) p-value† Difference in mean (95% CI)†† p-value
Calcaneus inverted
angle, degrees § 1.046 ± 5.053 −2.245 ± 5.648 0.014 3.109 (0.037, 6.181) 0.047
Calcaneus alignment,
no (%) §§
0.218
Everted calcaneus 5 (13.2) 8 (26.7)
Normal calcaneus 27 (71.1) 20 (66.7)
Inverted calcaneus 6 (15.8) 2 (6.7)
PFOA: patellofemoral osteoarthritis; TFOA: tibiofemoral osteoarthritis; 95% CI: 95% confidence interval
Except where otherwise indicated, values are mean ± SD
† Based on Student t-test (calcaneus inverted angle) and the Fisher’s exact tests (calcaneus type) between two groups
†† Adjusted for age, (continuous), sex (0: male, 1: female), body mass index (continuous), tibiofemoral joint Kellgren/Lawrence grade
(continuous), corrected anatomical axis angle (continuous), presence of varus thrust (0: absence, 1: presence), and knee flexion range of
motion (continuous)
§ A positive value indicates inversion direction of the calcaneus.
§§ Inverted calcaneus: calcaneus angle ≤ − 5 degree; normal calcaneus: −5 degree < and ≤ 5 degree; everted calcaneus: calcaneus angle
> 5 degree.
Bold type represents a statistically significant result
Current Pedorthics | November/December 2018
31