Altered Multisegment Ankle and Foot Kinematics During Gait in Patients With Hypermobile Ehlers-Danlos Syndrome/Hypermobility Spectrum Disorder: A Case-Control Study.

OBJECTIVE: Ankle-foot problems have a considerable impact on daily functioning in patients with hypermobile Ehlers-Danlos syndrome and hypermobility spectrum disorder (hEDS/HSD). Therefore, the objective of this study was to identify alterations in multisegment ankle and foot kinematics during gait and to assess foot function and pain in these patients. METHODS: Twenty-three women with hEDS/HSD and 23 healthy controls participated in this 3-dimensional gait analysis. Multisegment ankle and foot kinematics were collected using the Ghent Foot Model and analyzed with Statistical Parametric Mapping. Foot function and pain were assessed using visual analog scale scores, the Margolis Pain Diagram, and the Foot Function Index. RESULTS: Levels of pain and foot dysfunction were significantly higher in subjects with hEDS/HSD (P < 0.001). Kinematic curve analyses provide evidence for a hypermobile first ray, represented by a significantly increased eversion position of the medial forefoot during stance phase (P < 0.001) in subjects with hEDS/HSD compared to controls. In addition, significantly more dorsiflexion was found in the medial and lateral forefoot and the rearfoot (P < 0.001). At the midfoot, an increased plantar flexion (P < 0.001) and at the level of the hallux a decreased dorsiflexion (P = 0.037) and increased inversion (P < 0.001) and abduction (P = 0.016) were found in subjects with hEDS/HSD. CONCLUSION: This study is the first to apply a multisegment foot model during gait in hEDS/HSD, which confirms the characteristic hypermobility throughout the foot, especially the hypermobile first ray.

The subtalar joint axis palpation technique-part 1: validating a clinical mechanical model.

BACKGROUND: Locating the position of the subtalar joint axis can be a predictive clinical variable in biomechanical analysis and a valuable tool in the design of functional foot orthoses. Before testing Kirby's palpation technique to locate the subtalar joint axis in cadavers, it was important to develop and test the experimental methods in a mechanical model in which the exact location of the hinge joint can be controlled. METHODS: Four testers determined the hinge joint location and moved it through its range of motion, capturing the movement of the joint axis using a kinematic model. The joint axis location was determined and validated by comparing the actual hinge joint location on the mechanical model with the location determined by the palpation technique described by Kirby in 1987 and the location determined by the helical joint axis method using three-dimensional kinematic data. RESULTS: The overall angles result in mean slopes and intersections of 87° and 92 mm, 86° and 97 mm, 85° and 92 mm, and 88° and 91 mm for testers 1, 2, 3, and 4, respectively. Testers 1 and 3 were able to determine the location to 1° and 1 mm accuracy, tester 2 to 0° and 4 mm, and tester 4 to 2° and 2 mm compared with the kinematic data. CONCLUSIONS: The technique of determining the points of no rotation as described by Kirby could be validated by using a three-dimensional kinematic model to determine the helical axis.

The Subtalar Joint Axis Palpation Technique: Part 2 - Results on reliability and validity using cadaver feet.

Abstract Background Clinically locating the point of no rotation to determine the subtalar joint axis (STJA) location by applying pressure on the plantar surface of the foot, was described by Kirby in 1987, but never validated. The purpose of this study is to extend a previously validated mechanical model to cadaver feet and to examine the intra-intertester reliability. Methods Four testers, with different levels of experience, determined the STJA location and moved the STJ through its range of motion capturing the movement using kinematic analysis. The comparison of the spatial STJA location determined by palpation between and within testers determined the inter- and intratester reliability. The helical axis method was performed to validate the model. Results The intrarater reliability varies from high (α = 0.96) to low (α = 0.26) for the slope and is in general high (α between α= 0.78 and α=0.95) for the intersection. The interrater reliability scores moderate to high, depending on the specific cadaver specimen. Concerning the exact location of the subtalar joint axis, no significant difference was found between the results determined by different testers and the helical axis method. Conclusion The palpation technique as part of the Subtalar Axis Location and Rotational Equilibrium Theory proposed by Kirby is a reliable and valid clinical tool. Experience in performing the palpation technique has a positive influence on the accuracy of the results. In the context of evidence based practice, this technique could be a standard tool in the examination of patients with lower limb related pathology.

The subtalar joint axis palpation technique part 2: reliability and validity results using cadaver feet.

BACKGROUND: Clinically locating the point of no rotation to determine the subtalar joint axis location by applying pressure on the plantar surface of the foot was described by Kirby in 1987 but was never validated. We sought to extend a previously validated mechanical model to cadaver feet and to examine the intratester and intertester reliability. METHODS: Four testers with different levels of experience determined the subtalar joint axis location and moved the subtalar joint through its range of motion, capturing the movement using kinematic analysis. The comparison of the spatial subtalar joint axis location as determined by palpation between and within testers determined the intertester and intratester reliability. The helical axis method was performed to validate the model. RESULTS: The intrarater reliability varied from a high of α = 0.96 to a low of α = 0.26 for the slope and was, in general, high (α = 0.78-0.95) for the intersection. The interrater reliability scored moderate to high, depending on the specific cadaver specimen. Concerning the exact location of the subtalar joint axis, no significant difference was found between the results determined by different testers and the helical axis method. CONCLUSIONS: The palpation technique as part of the subtalar joint axis location and rotational equilibrium theory proposed by Kirby is a reliable and valid clinical tool. Experience in performing the palpation technique has a positive influence on the accuracy of the results. In the context of evidence-based practice, this technique could be a standard tool in the examination of patients with lower-limb-related pathologic disorders.

Intratest reliability in determining the subtalar joint axis using the palpation technique described by K. Kirby.

BACKGROUND: Exact determination and classification of the spatial position of the subtalar joint axis could be a predictive clinical variable in biomechanical analysis and a valuable tool in the design of functional foot orthoses. METHODS: Three clinicians with different levels of experience determined and classified the subtalar joint axis location, three times, on 52 individuals, using the clinical palpation, allocation and interpretation technique, as described by K. Kirby. RESULTS: High intratester precision (ICC 0.72 to 0.93) was found for determining the axis location (SEM, 3.72° for angle/0.27 cm for X-axis); however, classification of the spatial position of the axis has large intertester variation (κ = 0.243 to 0.494) CONCLUSIONS: The clinical palpation technique itself is reliable; the consistent attribution of a classification, in other words, interpretation, is weak.