Background
Methods
Intervention and usual care
Baseline laboratory assessment
Primary outcome measure
EVB | Principal axis | 2nd axis | 3rd axis |
---|---|---|---|
Foot | Line connecting the heel and toe markers that is offset by ½ inter-malleolar distance (ux) | Line running from the heel marker to ankle marker and orthogonal to the principal axis (uz) | Orthogonal to 1st and 2nd axes (uy) |
Shank | Ankle joint centre to knee joint centre (uz) | Tibial wand orientation orthogonal to principal axis (ux) | Orthogonal to 1st and 2nd axes (uy) |
Secondary outcome measures
-
Stride length: recorded on the walkway as the distance between the heel markers using CODA analysis.
-
Forefoot PPP: pressure was measured barefoot using a two-step gait initiation protocol [59, 60] using a pressure sensing mat (Tekscan MatScan system, Tekscan Inc., Boston, USA), calibrated to bodyweight. On average, eight to 10 trials were carried out to capture three steps for each foot. A mean forefoot peak pressure value of the three steps was calculated (ICC = 0.75) [61]. Inaccurate trials were excluded, for example if the participant targeted, missed, stopped on the mat.
-
Forefoot-to-rearfoot pressure ratio (F/R ratio): using FootMat software the forefoot (F) and (R) rearfoot regions were masked. The forefoot-to-rearfoot pressure ratio value was derived from the foot with the highest pressure using the formula: F/R. Increases in the F/R ratio are thought to play a prominent role in DFU [62].
-
Postural Sway: unperturbed balance was assessed during a 30-s quiet standing period using a portable force plate (Kistler). The centre of pressure (antero-posterior and medio-lateral) velocity was calculated as participants stood with arms by their side and barefoot, and their feet parallel and 4 cm apart with eyes open and closed. The order of testing was randomised by the assessor. Three readings per condition were taken and the mean value was calculated. If participants were required to step or hold onto a support during the trial, another trial was recorded following the participant’s consent. Force plate data was filtered (Butterworth low pass (20 Hz, 1st order) offline and the centre of pressure velocity calculated.
-
Functional Reach test (FRT): participants stood in front of a graph paper grid with the arm outstretched and the hand in a fist [63]. The participant was instructed to reach forwards without taking a step and the horizontal distance moved by the 3rd metacarpal head was measured. A familiarization trial followed three readings and the mean value of these recordings was calculated.
-
Bilateral static ankle joint dorsiflexion: the weight-bearing lunge test was used to assess static ankle dorsiflexion ROM on both feet [64]. This test was carried out against a stable surface (i.e., door frame). Participants were asked to stand with both feet facing the wall. Participants were then instructed to lunge forward until their knee touched the door frame without lifting their heel off the floor. Participants were given 5 attempts to achieve the greatest distance between their big toe and the wall, for each ankle. Attention was paid to avoid midfoot dorsiflexion [65]. The maximum distance in centimetres (cm) from the wall to the tip of the big toe was recorded using a tape measure positioned on the floor.
-
Bilateral static hallux dorsiflexion: weight-bearing static hallux dorsiflexion ROM was measured using a rig consisting of two segments of wood that were hinged [66]. The subject was asked to stand on the rigs with the centre of the 1st MTP joint positioned over the hinge in their natural base of stance whilst looking straight ahead. The distal segment of the wood was then hinged upwards via a connected in-series strain gauge until resistance was felt whilst or when a maximum force of 2 Kgs was applied. The hallux dorsiflexion angle was measured via a digital inclinometer attached to the distal segment of the rig [66] (Fig. 2). A familiarisation trial was carried out, before an average of 3 readings per hallux were recorded.
-
Exercise adherence and fidelity: the number of therapy sessions attended in the intervention group and the intervention delivered was recorded from standardised therapy notes (Additional File 3). The number of exercises performed at home was determined by weekly diary sheets completed by the participants.
Analysis
Results
Parameters | Baseline (All Participants) | Participants lost to follow-up | Remaining participants at post-intervention | |||||
---|---|---|---|---|---|---|---|---|
Intervention N = 31 | Control N = 30 | p | Intervention N = 4 | Control N = 2 | Intervention N = 27 | Control N = 28 | p | |
Age (yrs) Mean (std) | 70.49 (8.7) | 68.3 (10.34) | t(59) = .89 p = .38 | 66.2 (10.56) | 79.5 (4.94) | 71.1 (8.45) | 67.5 (10.20) | t(53) = -1.42 p = .31 |
BMI (Kg/m2) Mean (std) | 32.67 (6.98) | 31.9 (5) | U = 458.5 p = .93 | 30 (4.1) | 29.1 (9.62) | 33.1 (7.4) | 32.1 (4.78) | U = 375.5 p = .97 |
Neuropathy Severity (10 g Monofil No. correct responses) (Median score (IQR) | 4 (5.25) | 3.5 (4) | U = 407.5 p = .40 | 1.5 (6) | 3.5 (-) | 4 (4) | 3.5 (5) | U = 314.5, p = .28 |
Neuropathy (Neurothesiometer) (Mean(std) | 32.10 (15) | 33.7(14.6) | U = 447, p = .76 | 31.5(17) | 33.3(16.6) | 32.2(15.1) | 33.8(14.82) | U = 359.5 p = .72 |
Type I Diabetes No. (%) | 2(6.45) | 5(16.66) | χ2(1) = .1.6 p = .21 | 0 | 0 | 2(7.69) | 5(21.43) | χ2(3) = 2.34 p = .51 |
Duration of Diabetes Mean (std) | 13.8 (9.75) | 18.5 (13.3) | U = 385, p = .25 | 20.25 (18.7) | 26 (4.24) | 12.81 (7.9) | 18 (13.6) | U = 319.5 p = .324 |
Forefoot Deformity Mean (std) | 1.4 (.9) | 1.4 (.8) | U = 458.5 p = .92 | 1.75(0.95) | 0(0) | 1.3 (0.9) | 1.37 (.82) | U = 364.5 p = .81 |
Peripheral Arterial Blood Supply Mean (std) | 2.5 (.67) | 2.4 (.96) | U = 463, p = .98 | 2.75(0.5) | 0(0) | 2.5 (.69) | 2.4 (.98) | U = 374.5 p = .95 |
Limited Joint Mobility Syndrome Prayer Sign – no limitation No.(%) | 8(25.80) | 11(36.66) | χ2(3) = 2.1 p = .54 | 2(40) | 0(0) | 6(23.07) | 11(39.28) | χ2(9) = 2.5 p = .28 |
Limited Joint Mobility Syndrome Table Top Sign – no limitation (%) | 9(29.03) | 11(36.66) | χ2(3) = 2.80 p = .42 | 2(40) | 0(0) | (7)26.92 | 11(39.28) | χ2(9) = 3.1 p = .22 |
Foot Posture Index Mean (std) | 3.01 (3.87) | 2.19 (4.05) | t(59) = .820 p = .42 | 2.4 (5.15) | 2.5 (0.70) | 3.11 (3.76) | 2.16 (4.20) | t(53) = -.88 p = .26 |
Callus forefoot Not Present No. (%) | 24(77.4) | 22(73.3) | χ2(2) = .737 p = .69 | 3(75) | 2(100%) | 21(77.8) | 20(71.4) | χ2(6) = 5.4 p = .49 |
Callus hallux Not Present No. (%) | 27(87.1) | 22(73.3) | χ2(2) = 1.83 p = .40 | 4(100) | 1(50) | 23(85.2) | 21(75) | χ2(6) = 3.95 p = .68 |
No. of Falls Median (IQR) | 0(1) | 0 (0) | U = 378.5 p = .07 | 0 (0) | 0(0) | 0(1) | 0 (0) | U = 294.5 p = .05 |
Gait
Ankle dorsiflexion in gait
Outcome | Control | Intervention | Statistical Testing | Hedges G (95% CI) Effect Size Hedges g (95% Confidence Interval) | ||||
---|---|---|---|---|---|---|---|---|
n | Baseline Mean (SD) | 6 weeks Follow up Mean (SD) | n | Baseline Mean (SD) | 6 weeks follow up Mean (SD) | (95% CI) | ||
Right Ankle DF stance (o) | 28 | 20.5 (4.0) | 20.2 (4.2) | 27 | 20.4 (4.1) | 21.3 (5) | F (1,52) = 1.4 P = .242 | -0.31 (-0.22, 0.84) |
Left Ankle DF stance(o) | 28 | 21 (4.9) | 21 (4.5) | 27 | 20.7 (3.8) | 21.9 (4.6) | F (1,52) = 0.96 P = .33 | 0.28 (-0.26, 0.81) |
Right Ankle DF swing(o) | 28 | 9 (4.1) | 8.8 (3.5) | 27 | 9.8 (3.5) | 10.8 (4.5) | F (1,52) = 1.94 P = .169 | 0.30 (-0.23, 0.83) |
Left Ankle DF swing(o) | 28 | 9.7 (5) | 10 (4.9) | 27 | 8.9 (3.6) | 10.6 (4.3) | F (1,52) = 1.01 P = .318 | 0.33 (-0.20, 0.86) |
R Ankle total range(o) | 28 | 24.3 (4.4) | 24.8 (3.8) | 27 | 23.9 (3.5) | 24.6 (3.8) | F (1,52) = .015, P = .902 | 0.08 (-0.45, 0.61) |
L Ankle total range(o) | 28 | 24.8 (4.7) | 25 (5) | 27 | 24.3 (4.5) | 25.4 (3.8) | F (1,52) = 1.04, P = .312 | 0.30 (-0.23, 0.83) |
R Step length (mm) | 28 | 1011.3 (149.6) | 1070.4 (142.9) | 27 | 978.6 (238.3) | 1033.1 (288.4) | F (1,52) = .021, P = .884 | -0.05 (-0.57, 0.48) |
L Step length (mm) | 28 | 994.3 (165) | 1058.6 (150.6) | 27 | 959.2 (232) | 1035.6 (285.9) | F (1,52) = .082, P = .776 | 0.09 (-0.43, 0.62) |
R Stride length (mm) | 28 | 504.5 (76.9) | 531.3 (701) | 27 | 500 (126.4) | 513.1 (146.3) | F (1,52) = .644, P = .426 | -0.21 (-0.74, 0.32) |
L Stride length (mm) | 28 | 502.2 (88) | 532.7 (78.2) | 27 | 489 (124.9) | 514 (144.1) | F (1,52) = .15, P = .703 | -0.07 (-0.60, 0.46) |
R Peak FF Pres. (KPa) | 27 | 627 (216.3) | 625 (202.2) | 26 | 678.9 (257.5) | 620.8 (189) | F (1,50) = .42, P = .519 | -0.28 (-0.82, 0.26) |
L Peak FF Pres. (KPa) | 27 | 631.2 (221.8) | 620.2 (194.8) | 26 | 623.3 (198.3) | 584.1 (157.5) | F (1,50) = .580, P = .450 | -0.14 (-0.68, 0.40) |
R FP ratio | 27 | 1.6 (0.5) | 1.5 (0.42) | 26 | 1.5 (0.54) | 1.4 (0.48) | F (1,50) = .006, P = .941 | 0.12 (-0.42, 0.65) |
L FP ratio | 27 | 1.53 (0.65) | 1.39 (0.41) | 26 | 1.30 (0.33) | 1.33 (0.48) | U = 371, Z = –0.12, P = .906 | 0.43 (-0.11, 0.98) |
Sway EO (mm/s) | 28 | 21.5 (12.94) | 20.54 (9.95) | 27 | 22.65 (10.31) | 20.49 (7.31) | U = 362, Z = -.035, P = .972 | -0.20 (-0.73, 0.33) |
Sway EC (mm/s) | 28 | 40.31 (29.84) | 36.38 (26.79) | 27 | 41.20 (21.92) | 34.50 (16.70) | U345, Z = -.329, P = .742 | -0.18 (-0.71, 0.35) |
R Static Ankle DF (cm)** | 28 | 6.21 (4.18) | 5.71 (3.70) | 27 | 6.42 (2.90) | 8.04 (3.19) | F(1,52) = 24.0 P = .000 | 1.25 (0.67, 1.82) |
L Static Ankle DF (cm)** | 28 | 6.64 (3.60) | 6.36 (3.49) | 27 | 7 (3.46) | 8.52 (3.93) | F(1,52) = 13.03, P = .001 | 0.95 (0.39, 1.51) |
R Static Hallux DF (cm) | 28 | 17.44 (7.86) | 16.93 (6.13) | 26 | 12.82 (4.12) | 15.64 (5.66) | F(1,51) = 1.446, P = .235 | 0.66 (0.11, 1.21) |
L Static Hallux DF (cm)* | 28 | 15.79 (8.15) | 15.51 (7.1) | 27 | 12.13 (6.50) | 14.88 (6.59) | F = (1,52) = 4.071, P = .049 | 0.72 (0.17, 1.26) |
Functional Reach (cm)* | 28 | 27.61 (6.83) | 27.89 (7.48) | 27 | 25.90 (8.49) | 29.03 (8.32) | F(1,52) = 5.674, P = .021 | 0.69 (0.14, 1.23) |
Walking Speed (m/s) | 28 | 12 (2.94) | 11.62 (2.81) | 27 | 12.5 (3.14) | 11.41 (2.91) | U = 354.5, Z = -.165, P = .869 | -0.11 (-0.62, 0.39) |
Stride length, forefoot PPP and F/R ratio
Outcome | Control | Intervention | Statistical Testing | Hedges G (96% CI) Effect Size Hedges g (95% Confidence Interval) | ||||
---|---|---|---|---|---|---|---|---|
n | Baseline Mean (SD) | 18 weeks Follow up Mean (SD) | n | Baseline Mean (SD) | 18 weeks follow up Mean (SD) | (95% CI) | ||
Right Ankle DF stance (o) | 24 | 20.35(4.2) | 20.28 (4.5) | 24 | 20.55(4.2) | 19.92(4.98) | F(1,45) = .167, p = .685 | -0.13 (-0.69, 0.44) |
Left Ankle DF stance(o) | 24 | 20.7(5) | 20.8(4.6)21.4(5.7) | 24 | 20.8(3.4) | 21.4(5.7) | F(1,45) = .173, P = .679 | 0.10 (-0.46, 0.67) |
Right Ankle DF swing(o) | 24 | 8.88(4.1) | 9.03(3.4) | 24 | 9.84(3.7) | 9.43(3.9) | F(1,45) = .002. P = .966 | -0.12 (-0.68, 0.45) |
Left Ankle DF swing(o) | 24 | 9.9(5.3) | 10.4(5.2) | 24 | 9(3.7) | 10.1(5.8) | U = 233, Z = -.915, P = .360 | 0.12 (-0.44, 0.69) |
R Ankle total range(o) | 24 | 24.62(4.51) | 24.2(3.5) | 24 | 24.05(3.6) | 23.7(4.2) | F(1,45) = .029, P = .865 | 0.01 (-0.55, 0.58) |
L Ankle total range(o) | 24 | 25.1(5) | 24.8(5.2) | 24 | 24.1(4.5) | 25.4(4.2) | F(1,45) = 1.302, P = .260 | 0.39 (-0.18, 0.96) |
R Step length (mm) | 24 | 1013.3(150) | 1058.3(134.9) | 24 | 975.3(248.5) | 1017.5(291) | U = 253, Z = -.489, P = .625 | -0.03 (-0.59, 0.54) |
L Step length (mm) | 24 | 996.6(166.2) | 1050.8(126.4) | 24 | 954.3(242) | 982.8(275) | U = 244.5, Z = -.670, P = .503 | -0.24 (-0.81, 0.33) |
R Stride length (mm) | 24 | 506.6(75.3) | 523(63.8) | 24 | 498.8(132.1) | 504.1(152.2) | U = 252, Z = -.511, P = .610 | -0.20, (-0.77, 0.36) |
L Stride length (mm) | 24 | 502.2(88.2) | 512.6(63.4) | 24 | 486.6(130.9) | 499.7(154.3) | F(1,45) = .008, P = .930 | 0.05 (-0.52, 0.61) |
R Peak FF Pres. (KPa) | 24 | 639.9(209.2) | 572.6(157.5) | 23 | 683.9(271.5) | 576.9(232.8) | F(1,44) = .089, P = .767 | -0.18 (-0.76, 0.39) |
L Peak FF Pres. (KPa) | 24 | 633.2(215.2) | 582(156.2) | 23 | 629.7(206.5) | 552.8(188.6) | F(1,44) = .340, P = .563 | -0.11 (-0.69, 0.46) |
R FP ratio | 24 | 1.6(0.5) | 1.6(0.5) | 23 | 1.5(0.6) | 1.5(0.5) | F(1,44) = .029, P = .866 | 0.06 (-0.51, 0.63) |
L FP ratio | 24 | 1.5(0.7) | 1.5(0.7) | 23 | 1.3(0.4) | 1.4(0.3) | U = 282, Z = -.114, P = .910 | 0.16 (-0.41, 0.73) |
Sway EO (mm/s) | 24 | 20.1(9.8) | 17.5(6.4) | 24 | 22.8(10.6) | 21.6(9.4) | U = 236, Z = -.851, P = .395 | 0.22 (-0.35, 0.78) |
Sway EC (mm/s) | 24 | 38.8(26.3) | 32.8(20.1) | 24 | 41.2(22.5) | 37.5(20.3) | U = 239, Z = -.787, P = .431 | 0.16 (-0.40, 0.73) |
R Static Ankle DF (cm)** | 25 | 6.5 (4.3) | 6.2(3.8) | 24 | 6.3(3) | 9(3.3) | F(1,46) = 31.346, P = 0.000 | 1.54 (0.90, 2.17) |
L Static Ankle DF (cm)** | 25 | 7.2(3.3) | 6.7(3.2) | 24 | 6.6(3.6) | 9.5(3.7) | U = 170.5, Z = -2.43, P = .015 | 1.43 (0.80, 2.05) |
R Static Hallux DF(o)** | 25 | 18.1(8) | 16.6(6.2) | 23 | 12.5(4.2) | 17.4(5) | F(1,45) = 14.833, P = 0.000 | 1.51 (0.86, 2.15) |
L Static Hallux DF(o) | 25 | 16(8.6) | 14.4(5.7) | 24 | 11.6(6.1) | 16.8(5.4) | U = 226.5, Z = -1.26, P = .208 | 1.10 (0.50, 1.70) |
Functional Reach (cm)* | 25 | 27.3(7.1) | 27.6(7.8) | 24 | 25.3(8.5) | 29.2(9.4) | F(1,45) = 7.063, P = .011 | 0.81 (0.22, 1.40) |
Walking Speed (m/s) | 25 | 12(2.9) | 11.7(2.8) | 24 | 13.1(4.2) | 11.3(3.7) | U = 243, Z = -.918, P = .358 | -0.51 (-1.09, 0.06) |