Medially wedged foot orthoses generate greater biomechanical effects than thin-flexible foot orthoses during a unilateral drop jump task on level and inclined surfaces.

BACKGROUND: Foot orthoses are therapeutic insoles designed to induce various effects on lower limb biomechanics. However, conflicting findings in previous research, highlight the need to better understand how foot orthoses with different features affect lower limb biomechanics during challenging tasks, particularly during unilateral drop jump landings. METHODS: Seventeen participants with flat feet were recruited to participate in this cross-sectional descriptive study that examined the effects of thin-flexible foot orthoses and medially wedged foot orthoses on lower limb biomechanics during unilateral drop jump landings on level and valgus inclined surfaces. Midfoot, ankle, knee, and hip angles and moments were calculated and compared across conditions with repeated measures ANOVAs, using a statistical parametric mapping approach. FINDINGS: Medially wedged and thin-flexible foot orthoses reduced ankle pronation and arch flattening during unilateral drop jump landings on level and valgus inclined surfaces. Medially wedged foot orthoses further decreased midfoot dorsiflexion and ankle eversion angles compared to thin-flexible foot orthoses. Medially wedged foot orthoses also generated greater effects on ankle kinetics and hip kinematics during unilateral drop jump landings. INTERPRETATION: Medially wedged foot orthoses are more effective than thin-flexible foot orthoses in optimizing lower limb biomechanics during unilateral drop jump landings. While the biomechanical effects did not increase on inclined surfaces, medially wedged foot orthoses generated greater effects on proximal joints, highlighting their potential to improve hip stability and enhance overall lower limb function. Personalized foot orthoses selection based on specific biomechanical profiles should be further explored to optimize orthotic interventions benefiting individuals with musculoskeletal conditions.

Supination resistance variations in foot and ankle musculoskeletal disorders: implications for diagnosis and customised interventions with wedged insoles.

BACKGROUND: Supination resistance is a clinical outcome that estimates the amount of external force required to supinate the foot. A greater supination resistance may indicate greater loads on structures responsible for generating internal supination moments across the subtalar joint during static and dynamic tasks. As such, greater supination resistance may be an expected finding in medial foot and ankle musculoskeletal disorders, such as plantar fasciopathy (PF) and posterior tibial tendon dysfunction (PTTD), whereas reduced supination resistance may be present in lateral ankle disorders, such as chronic ankle instability (CAI). However, no studies have yet investigated the changes in supination resistance across these foot and ankle musculoskeletal disorders. This study aimed to quantify supination resistance in individuals with PF, PTTD and CAI compared to healthy controls. Additionally, this study aimed to explore the changes in supination resistance following the simulation of varus and valgus wedges, which are commonly used interventions for these disorders. METHODS: Fourteen participants with PF, fourteen with PTTD, fourteen with CAI and fourteen healthy controls were recruited. Supination resistance was quantified on a level surface and on a 10-degree inclined surface with varus and valgus positions. RESULTS: Supination resistance was lower for the injured foot for CAI (p < 0.001) and greater for PTTD (p < 0.001) compared to the healthy foot. There was no significant between-foot difference observed for PF (p = 0.275) and controls (p = 0.970). In the injured foot, CAI exhibited lower supination resistance compared to controls (p < 0.001), PF (p = 0.012) and PTTD (p = 0.014). Regardless of the groups, supination resistance increased when tested on a surface with valgus inclination (p < 0.001) and decreased when tested on a surface with varus inclination (p < 0.001). CONCLUSIONS: Varus and valgus inclinations to the surface were effective in modifying supination resistance in PTTD and CAI, respectively. Supination resistance seemed unchanged in PF, and thus inclining the standing surface leads to greater between-feet asymmetries. This study also highlights the potential of wedged insoles as a mean to customise treatments and modify tissue stresses in these disorders. The findings contribute to the understanding of foot and ankle biomechanics and may aid in the development of more effective management and rehabilitation strategies.

Intrarater and interrater reliability of the first metatarsophalangeal joint dorsiflexion resistance test.

BACKGROUND: The first metatarsophalangeal joint plays a fundamental role during the gait cycle. The Hubscher manoeuvre, which consists of passively dorsiflexing the first metatarsophalangeal joint of an individual in relaxed stance and observing the raising of the medial longitudinal arch, is a clinical test thought to examine the function of the first metatarsophalangeal joint. However, the hallux dorsiflexion achieved during this test is not related to hallux dorsiflexion during gait. On the other hand, unlike kinematic tests, results from kinetic tests have been shown to be strongly correlated with dynamic joint biomechanics. Thus, given the need for valid and reliable tests to evaluate the function of the first metatarsophalangeal joint, this study aimed to assess the reliability of a new kinetic test, namely, the first metatarsophalangeal joint dorsiflexion resistance test. METHOD: Thirty young adults completed two data collection sessions 1 week apart, during which the first metatarsophalangeal joint dorsiflexion resistance test was performed. Intrarater and interrater reliability were assessed using intraclass correlation coefficients (ICC), minimal detectable difference (MDD), standard error of the mean (SEM) and limits of agreements (LoA). RESULTS: For the intrarater reliability, the ICC was 0.77 (p < 0.001), the SEM was 6.5 N, the MDD was 18.1 N and the LoA were -7.9 to 26.9 N. For the interrater reliability, the ICC was 0.86 (p < 0.001), the SEM was 6.9 N, the MDD was 19.0 N and the LoA were -6.4 to 21.8 N. CONCLUSION: The results of this study demonstrate good intra and interrater reliability of the first metatarsophalangeal joint dorsiflexion resistance test, which provides evidence to support its use in clinical and research contexts. Further work is required to establish the test results' relationship with joint kinetics during gait and to provide normative values in individuals with and without musculoskeletal disorders as well as among different age groups and genders to optimise its utilization in clinical and research settings.

The Keystone device as a clinical tool for measuring the supination resistance of the foot: A reliability study.

BACKGROUND: The supination resistance test (SRT) is a kinetic test used in clinical and research contexts to estimate the amount of force required to supinate the foot. Previous studies either used a manual, less reliable version of this test or a more reliable instrumented version, but with devices inconvenient for clinical use. The clinically available Keystone device has been developed for the SRT, and could be better suited for clinical purposes. The objective of this study is to determine the intrarater and interrater reliability of the Keystone device for the SRT. METHOD: Thirty young adults underwent two prospective experimental sessions, 1 week apart, during which SRT measures with the Keystone device were registered. Intrarater and interrater reliability were calculated using intraclass correlation coefficients (ICC), standard error of measurement (SEM), minimal detectable difference (MDD) and limits of agreements (LoA). RESULTS: The intrarater reliability of the SRT was good (ICC = 0.86, p < 0.001). The SEM, MDD and 95% LoA were 7.3, 20.4 and -31.6-14.3 N, respectively. The interrater reliability of the SRT was good (ICC = 0.76, p < 0.001). The SEM, MDD and 95% LoA were 9.0, 24.9 and -36.6-24.9 N, respectively. CONCLUSION: The Keystone device is a reliable tool that can be used in clinical and research contexts. Prospective studies aiming to determine if SRT measures are predictors of musculoskeletal injuries or if they can predict the effects of external supports on the biomechanics of the foot and ankle are warranted.