ISB recommendation on definitions of joint coordinate system of various joints for the reporting of human joint motion—part I: ankle, hip, and spine

Background While successful subtalar joint arthrodesis provides pain relief, resultant alterations in ankle biomechanics need to be considered, as this procedure may predispose the remaining hindfoot and tibiotalar joint to accelerated degenerative changes. However, the biomechanical consequences of isolated subtalar joint arthrodesis and additive fusions of the Chopart's joints on tibiotalar joint biomechanics remain poorly understood. Questions/purposes We asked: What is the effect of isolated subtalar fusion and sequential Chopart's joint fusions of the talonavicular and calcaneocuboid joints on tibiotalar joint (1) mechanics and (2) kinematics during loading for neutral, inverted, and everted orientations of the foot? Methods We evaluated the total force, contact area, and the magnitude and distribution of the contact stress on the articular surface of the talar dome, while simultaneously tracking the position of the talus relative to the tibia during loading in seven fresh-frozen cadaver feet. Each foot was loaded in the unfused, intact control condition followed by three randomized simulated hindfoot arthrodesis modalities: subtalar, double (subtalar and talonavicular), and triple (subtalar, talonavicular, and calcaneocuboid) arthrodesis. The intact and arthrodesis conditions were tested in three alignments using a metallic wedge insert: neutral (flat), 10°i nverted, and 10°everted. Results Tibiotalar mechanics (total force and contact area) and kinematics (external rotation) differed owing to hindfoot arthrodeses. After subtalar arthrodesis, there were Each author certifies that he or she, or a member of their immediate family, has no commercial associations (eg, consultancies, stock ownership, equity interest, patent/licensing arrangements, etc) that might pose a conflict of interest in connection with the submitted article. Clinical Orthopaedics and Related Research ®A Publication of The Association of Bone and Joint Surgeons® decreases in total force (445 ± 142 N, 95% CI, 340-550 N, versus 588 ± 118 N, 95% CI, 500-676 N; p \ 0.001) and contact area (282 mm 2 , 95% CI, 222-342 mm 2 , versus 336 ± 96 mm 2 , 95% CI, 265-407 mm 2 ; p \ 0.026) detected during loading in the neutral position; these changes also were seen in the everted foot position. Hindfoot arthrodesis also was associated with increased external rotation of the tibiotalar joint during loading: subtalar arthrodesis in the neutral loading position (3.3°± 1.6°; 95% CI, 2°-4.6°; p = 0.004) and everted loading position (4.8°± 2.6°; 95% CI, 2.7°-6.8°; p = 0.043); double arthrodesis in neutral (4.4°± 2°; 95% CI, 2.8°-6°; p = 0.003) and inverted positions (5.8°± 2.6°; 95% CI, 3.7°-7.9°; p = 0.002), and triple arthrodesis in all loaded orientations including neutral (4.5°±1.8°; 95% CI, 3.1°-5.9°; p = 0.002), inverted (6.4°± 3.5°; 95% CI, 3.6°-9.2°; p = 0.009), and everted (3.6°± 2°; 95% CI, 2°-5.2°; p = 0.053) positions. Finally, after subtalar arthrodesis, additive fusions at Chopart's joints did not appear to result in additional observe...

Section: Ankle Positionmentioning

confidence: 99%

How Do Hindfoot Fusions Affect Ankle Biomechanics: A Cadaver Model

Hutchinson

Baxter

Gilbert

et al. 2016

“…The control subjects with elevated (C 55°) alpha angles also showed a larger mean omega zone of 20% (95% CI, 18-22; p = 0.004) and 16% (95% CI, 13-19; p = 0.007) for 60°and 90°of flexion, respectively, compared with the patients with FAI. Furthermore, the mean omega zone at 0°a nd 30°was larger with 23% (95% CI, 19-27; p = 0.017) and 22% (95% CI, 19-26; p = 0.004), respectively, whereas the mean omega zone in patients with FAI was 18% (95% CI, [15][16][17][18][19][20][21][22] and 16% (95% CI, [11][12][13][14][15][16][17][18][19][20] (Table 3). In contrast, the omega zone was similar in both control groups at any of the flexion positions (0°p = 0.806, 30°p = 0.925, 60°p = 0.345, 90°p = 0.136).…”

Section: Resultsmentioning

confidence: 99%

“…A clinical expert checked whether each segmentation contained all osseous contours of the CT scan. Thereafter, Articulis TM linked the bones as a joint; the x-, y-, and z-axes were determined according to the recommendations of the International Society of Biomechanics (ISB) [22]. An exception was made for the x-axis of the pelvis (ie, the horizontal or transversal plane), which we defined as the plane from the posteroinferior iliac spine to the anterosuperior spine, corresponding better to the in vivo (standing) x-axis of the human pelvis.…”

Section: Three-dimensional Modelmentioning

confidence: 99%

Can Combining Femoral and Acetabular Morphology Parameters Improve the Characterization of Femoroacetabular Impingement?

Bouma

Hogervorst

Audenaert

et al. 2015

Background Femoroacetabular impingement (FAI) presupposes a dynamic interaction of the proximal femur and acetabulum producing clinical symptoms and chondrolabral damage. Currently, FAI classification is based on alpha angle and center-edge angle measurements in a single plane. However, acetabular and femoral version and neck-shaft angle also influence FAI. Furthermore, each of these parameters has a reciprocal interaction with the others; for example, a shallow acetabulum delays impingement of the femoral head with the acetabular rim. Questions/purposes We introduce the new parameter ''omega zone,'' which combines five parameters into one: the alpha and center-edge angles, acetabular and femoral version, and neck-shaft angle. We sought to determine whether the omega zone could differentiate patients with FAI from (1) normal control subjects (alpha \ 55°), but also from (2) control subjects with elevated alpha angles (C 55°). Methods We evaluated CT data of 20 hips of male patients with symptomatic cam-type FAI and of 35 male hips extracted from 110 anonymized CT scans for vascular diagnosis. We excluded hips with osteoarthritis, developmental dysplasia, or coxa profunda (center-edge angle 20°-45°on AP pelvic view or corresponding coronal CT views). With dedicated software, femoral and pelvic orientation was standardized; we tested the omega zone in four hip positions in three distinct groups: patients with cam-type FAI (alpha [ 60°) and control subjects with normal (\ 55°) and high alpha angles (C 55°). Results The omega zone was smaller in patients with cam-type FAI than normal control subjects (alpha angle \ 55°) at 60°and 90°of flexion (mean, 12%; 95% confidence interval [CI], 7-17; p = 0.008; Cohen's d = 9%; 95% CI, 4-13; p = 0.003). Furthermore, the omega zone was smaller in all positions in patients with cam-type FAI than control subjects with high alpha angles (0°p = 0.017, 30°p = 0.004, 60°p = 0.004, 90°p = 0.007). In contrast, the omega zone did not differ between control subjects with normal or high alpha angles. In all hips, the omega zone decreased with flexion, corresponding to a decrease in remaining impingement-free motion with flexion.

“…The program reconstructed the surface geometry of the femur and pelvis as a triangle mesh. We chose an orthogonal coordinate system based on the recommendation of the International Society of Biomechanics [47] and oriented the pelvis so that the AP iliac spines were level and in the same frontal plane as the pubic symphysis (no lordosis or pelvic obliquity). We located the center of the natural femoral head by fitting a sphere to the articular surface of femoral head, using the same method to locate the center of the natural acetabulum.…”

Section: Methodsmentioning

confidence: 99%

Bony Impingement Limits Design-related Increases in Hip Range of Motion

Bunn

Colwell

D’Lima

2012

Background Factors affecting risk for impingement and dislocation can be related to the patient, implant design, or surgeon. While these have been studied independently, the impact of each factor relative to the others is not known. Questions/purposes We determined the effect of three implant design factors, prosthetic placement, and patient anatomy on subject-specific ROM. Methods We virtually implanted hip geometry obtained from 16 CT scans using computer models of hip components with differences in head size, neck diameter, and neck-shaft angle. A contact detection model computed ROM before prosthetic or bony impingement. We correlated anatomic measurements from pelvic radiographs with ROM.