Test-retest reliability of a clinical foot assessment device for measuring first metatarsophalangeal joint quasi-stiffness.

BACKGROUND: The stiffness of the first metatarsophalangeal joint (MTPJ) is of interest in cases such as hallux rigidus and apropulsive gait. Subjective rating of joint mobility as 'hypermobile, normal, or stiff' is an unreliable method. Previous instruments for the assessment of first MTPJ stiffness can be too hard and uncomfortable for test subjects. Recently, a new device using a load cell and optical fiber with fiber Bragg grating (FBG) sensors was developed to provide a comfortable means of clinical foot assessment. This study aimed to evaluate the test-retest reliability of this FBG-load cell device in measuring the first MTPJ quasi-stiffness. METHODS: The left foot of 13 female subjects were measured twice for their first MTPJ quasi-stiffness, approximately seven days apart. The FBG-load cell device measured the MTPJ range of motion from a resting position to maximum dorsiflexion and then returning to the resting start-position. The force applied by a clinician to displace the toe was simultaneously recorded using the load cell. The quasi-stiffness over the "working range" in loading and unloading directions were determined from the slope of the torque-angular displacement graph. The test-retest reliability of the MTPJ quasi-stiffness was evaluated using intra-class correlation coefficient [ICC (2,1)]. RESULTS: The reliability was almost perfect for MTPJ quasi-stiffness over the loading phase (ICC = 0.814), moderate for MTPJ quasi-stiffness over the unloading phase (ICC = 0.477) and moderate for MTPJ maximum range (ICC = 0.486). CONCLUSION: The foot assessment device comprising FBG and load cell was able to reliably measure the first MTPJ quasi-stiffness in a clinical setting. The measurement reliability was higher during the loading phase than the unloading phase.

First ray mobility and posterior tibial tendon dysfunction (PTTD) in persons with flatfoot: A case control study.

BACKGROUND: While posterior tibial tendon dysfunction (PTTD) commonly presents with flat feet and has been thought to be associated with first ray mobility, many flat-footed individuals are asymptomatic and do not experience any symptoms of PTTD. Thus, there is a need to control for foot type when studying factors related to PTTD. This study aimed to clarify if first ray mobility differed between flat-footed individuals with and without symptoms of PTTD. It was hypothesized that PTTD patients would display higher mobility of the first ray than asymptomatic flat-footed controls. METHODS: Given that PTTD patients were often flat-footed, asymptomatic flat-footed individuals were chosen as controls to remove flatfoot as a potential confounding factor. We recruited 32 flat-footed subjects, of which 16 exhibiting PTTD symptoms and 16 asymptomatic controls matched for age, sex and body mass index. First ray mobility was assessed using subjective classification ("stiff", "normal" or "hypermobile") and maximum dorsal displacement using a ruler indicator. Mann-Whitney U was used to test for between-groups differences. RESULTS: Subjective classification was similar between PTTD and control groups (both groups: 38% "normal" joint mobility). No significant differences were found between PTTD patients and asymptomatic controls in first ray displacement [median (IQR), PTTD: 6.00 (1.75) mm; control: 6.00 (1.00) mm; P=.31]. CONCLUSIONS: First ray mobility was not associated with PTTD in flat-footed persons. When evaluating symptoms of PTTD, clinicians should pay attention to factors other than first ray mobility.

Computer aided diagnosis of diabetic foot using infrared thermography: A review.

Diabetes mellitus (DM) is a chronic metabolic disorder that requires regular medical care to prevent severe complications. The elevated blood glucose level affects the eyes, blood vessels, nerves, heart, and kidneys after the onset. The affected blood vessels (usually due to atherosclerosis) may lead to insufficient blood circulation particularly in the lower extremities and nerve damage (neuropathy), which can result in serious foot complications. Hence, an early detection and treatment can prevent foot complications such as ulcerations and amputations. Clinicians often assess the diabetic foot for sensory deficits with clinical tools, and the resulting foot severity is often manually evaluated. The infrared thermography is a fast, nonintrusive and non-contact method which allows the visualization of foot plantar temperature distribution. Several studies have proposed infrared thermography-based computer aided diagnosis (CAD) methods for diabetic foot. Among them, the asymmetric temperature analysis method is more superior, as it is easy to implement, and yielded satisfactory results in most of the studies. In this paper, the diabetic foot, its pathophysiology, conventional assessments methods, infrared thermography and the different infrared thermography-based CAD analysis methods are reviewed.

A novel method of measuring passive quasi-stiffness in the first metatarsophalangeal joint.

BACKGROUND: First metatarsophalangeal joint (MTPJ) mobility is commonly assessed by its angular displacement (joint angle) or subjectively rated as 'hypermobile', 'normal' or 'stiff' by a clinician. Neither of these methods is ideal because displacement alone does not take into account the force required to displace the joint and subjective evaluation is not always reliable. This study presented a novel method to determine the passive quasi-stiffness of the first MTPJ. The reliability of the proposed method was also assessed. The first MTPJ passive quasi-stiffness of 13 healthy subjects were measured at two occasions, 7 days apart, by two testers (experienced and inexperienced). A tactile pressure sensing system was used to measure the force applied to dorsiflex the first toe by the testers. The torque (in Nmm) about the first MTPJ was calculated as the applied force (in N) multiplied by a moment arm (in mm), where moment arm was the length of the first proximal phalanx. A video camera recorded the motion of the first MTPJ, simultaneously with force measurements, to determine the joint angular displacement (in degrees) using the Dartfish software. The quasi-stiffness (in Nmm/degrees) was calculated as the slope of a graph where torque was plotted against first MTPJ angular displacement. Descriptive statistics of the first MTPJ quasi-stiffness were calculated. Intra-rater and inter-rater reliability were assessed using Bland and Altman plot, intraclass correlation coefficients (ICC), and standard error of measurement (SEM). RESULTS: First MTPJ quasi-stiffness of the subjects ranged widely from 0.66 to 53.4 Nmm/degrees. Intra-rater reliability for experienced tester was moderate (Session 1: 14.9 ± 14.6 Nmm/degrees, Session 2: 14.2 ± 8.5 Nmm/degrees, ICC = .568, SEM = 7.71 Nmm/degrees). Inter-rater reliability between experienced (12.6 ± 8.4 Nmm/degrees) and non-experienced (19.9 ± 9.2 Nmm/degrees) testers was poor (ICC = -.447, SEM = 11.29 Nmm/degrees). CONCLUSIONS: First MTPJ passive quasi-stiffness can be quantified from torque and angular displacement measurements using simple equipment in a clinical setting. The tester's experience affected the consistency in joint quasi-stiffness measurements.