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Background: Despite of many attempts to determine or correct hip and knee joint parameters via non-invasive techniques such as regression or functional methods, in conventional gait models the position of the ankle joint center still is assumed at the center point between malleoli., Research Question: The aim of this study was to estimate the ankle joint parameters using a functional approach., Methods: To this aim, we used data of 23 typically developed adults performing two different calibration motions. Subsequently, we applied functional approaches to determine the functional joint center and axis., Results: The results show significant differences for ankle joint parameters in all directions for both calibration motions applied with respect to the malleoli line. Most prominently, we find a shift of the ankle joint center of 7 % of the foot length anteriorly to the malleoli mid-point when applying functional calibration., Conclusion: These significant alterations of the ankle joint center and axis indicate the importance of accurate determination of ankle joint parameters and consequently their influence on the clinical outcome., Competing Interests: Declaration of Competing Interest There is no conflict of interest., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Background: Individuals with trans-tibial amputation show a greater peak prosthetic ankle power (push- off) when using energy storing and returning (ESAR) prosthetic feet as compared to solid-ankle cushion-heel feet. ESAR feet further contribute to the users' body support and thus limit prosthetic ankle motion. To improve ankle motion, articulating prosthetic feet have been introduced. However, articulating feet may diminish push-off., Research Question: Does a novel prosthetic foot, with a serial layout of carbon fibre leaf springs, connected by a multi-centre joint construction, have advantages in kinematics and kinetics over a conventional ESAR prosthetic foot?> METHODS: Eleven individuals with unilateral trans-tibial amputation were fitted with the novel foot (NF) and a conventional ESAR Foot (CF) and underwent 3D gait analysis. As an additional power estimate of the prosthetic ankle, a unified, deformable, segment model approach was applied. Eleven matched individuals without impairments served as a reference., Results: The NF shows an effective prosthetic ankle range of motion that is closer to a physiologic ankle range of motion, at 31.6° as compared to 15.2° with CF (CF vs. NF p = 0.003/NF vs. Reference p = 0.171) without reducing the maximum prosthetic ankle joint moment. Furthermore, the NF showed a great increase in prosthetic ankle power (NF 2.89 W/kg vs. CF 1.48 W/kg CF vs. NF p = <0.001) and a reduction of 19% in the peak knee varus moment and 13% in vertical ground reaction forces on the sound side for NF in comparison to CF., Significance: The NF shows that serial carbon fibre leaf springs, connected by a multi-centre joint construction gives a larger ankle joint range of motion and higher ankle power than a conventional carbon fibre structure alone. Consequently load is taken off the contralateral limb, as measured by the decrease in vertical ground reaction forces and peak knee varus moment., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The incidence of knee and hip joint osteoarthritis in subjects with below knee amputation (BK) appears significantly higher compared to unimpaired subjects, especially in the intact side. However, it is controversial if constant higher loads on the sound side are one of the major factors for an increased osteoarthritis (OA) incidence in subjects with BK, beside other risk factors, e.g. with respect to metabolism. The aim wasto investigate joint contact forces (JCF) calculated by a musculoskeletal model in the intact side and to compare it with those of unimpaired subjects and to further elucidate in how far increased knee JCF are associated with increased frontal plane knee moments. A group of seven subjects with BK amputation and a group of ten unimpaired subjects were recruited for this study. Gait data were measured by 3D motion capture and force plates. OpenSim software was applied to calculate JCF. Maximum joint angles, ground reaction forces, and moments as well as time distance parameters were determined and compared between groups showing no significant differences, with some JCF components of knee and hip even being slightly smaller in subjects with BK compared to the reference group. This positive finding may be due to the selected ESAR foot. However, other beneficial factors may also have influenced this positive result such as the general good health status of the subjects or the thorough and proper fitting and alignment of the prosthesis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Satisfactory short-term results after femoral derotation osteotomy (FDO) for the treatment of internal rotation gait in cerebral palsy have been reported by various authors. However, there are only a few longer-term studies reporting results 5 years after FDO and these are not in agreement. There are no reports on the clinical course beyond the pubertal growth spurt. 33 children with diplegia (n=59 legs, age: 10.5±3.6 years) and internally rotated gait were examined pre- (E0), 1 year (E1), 3±1 (E2) and 9±2 (E3) years after distal (27 legs) or proximal (32 legs) FDO as part of multilevel surgery, using standardized clinical exam and 3D gait-analysis at all examinations. The amount of intra-operative derotation averaged 25°. ANOVA was used for statistics (p<0.05). Mean hip internal rotation in stance at E0 of 17.3° was significantly changed to 1.0° of external rotation at E1 and was maintained at 4.2° at E3. The same clinical course was found for foot progression angle. The mid-point of passive hip rotation at E0 was 21°. This was significantly decreased to 6° at E1 and showed a small but significant increase reaching 12° at E3. The results of this study showed a good overall correction of internally rotated gait following FDO. These improvements were maintained at long-term follow-up after the pubertal growth spurt. Recurrence was observed in some cases with overall severe deterioration. In those patients persistent dynamic factors leading to recurrence should be further investigated., (Copyright © 2012 Elsevier B.V. All rights reserved.)

The evidence in support of distal rectus femoris transfer (DRFT) as part of single-event multilevel surgery (SEMLS) is limited due to inconsistent outcome reports and a lack of randomized studies. The purpose of this prospective randomized trial was to establish whether the results of SEMLS without DRFT are similar to those of a conventional approach that includes DRFT in the SEMLS. In all, 32 children with spastic diplegia (GMFCS I-III) and an indication for DRFT were recruited and randomized into a DRFT (15 children) and a NON-DRFT group (17 children) using a minimization method. During SEMLS, bilateral DRFT was performed only in the DRFT group. Three-dimensional gait analysis and clinical examination were performed before and 1 year after surgery. In both groups a significant increase in range of motion during swing and knee flexion velocity were found, which was significantly higher in the DRFT group. While peak knee flexion in swing (pKFSw) was preserved in the DRFT group and significantly decreased in the NON-DRFT group, pKFSw timing was significantly earlier in both groups. The clinical relevance of the higher overall benefits in the DRFT group is limited, considering that 33% of patients in this group did not benefit from the procedure. Furthermore, 53% of the NON-DRFT patients did not undergo what proved to be an unnecessary DRFT. Subgroup analysis showed benefits for patients with decreased pKFSw, while those with severe flexed-knee gait (normal or increased pKFSw) did not profit from DRFT. This may explain the inconsistent overall results, and DRFT is therefore not recommended as a "prophylactic" procedure in patients with severe flexed-knee gait., (Copyright © 2012 Elsevier B.V. All rights reserved.)