Valgus unloader knee braces are a conservative treatment option for medial compartment knee osteoarthritis (OA). These braces are designed to reduce painful, and potentially injurious compressive loading on the damaged medial side of the joint through application of a frontal-plane abduction moment. While some patients experience improvements in pain, function, and joint loading, others see little to no benefit from bracing [1]. Previous biomechanical studies investigating the mechanical effectiveness of bracing have been limited in either their musculoskeletal detail [2] or incorporation of altered external joint moments and forces [3]. The first objective was to model the relative contributions of gait dynamics, muscle forces, and the external brace abduction moment to reducing medial compartment knee loads. The second objective was to determine what factors predict the effectiveness of the valgus unloading brace. Seventeen people with knee OA (8 Female age 54.4 +/− 4.2, BMI 30.00 +/− 4.0 kg/m. 2. , Kellgren-Lawrence range of 1–4 with med. = 3) and 20 healthy age-matched controls participated in this study which was approved by the institutional ethics review board. Subjects walked across a 20m walkway with and without a Donjoy OA Assist knee brace while marker trajectories, ground reaction forces, and lower limb electromyography were recorded. The external moment applied by the brace was estimated by multiplying the brace deformation by is pre-determined brace-stiffness. For each subject, a representative stride was selected for each brace condition. A generic musculokeletal model with two legs, a torso, and 96 muscles was modified to include subject-specific frontal plane alignment and medial and lateral contact locations [4]. Muscle forces, and tibiofemoral contact forces were estimated using static optimization [4]. We defined brace effectiveness as the difference in the peak medial contact force between the braced and the unbraced conditions. A stepwise regression analysis was performed to predict brace effectiveness based on: X-ray frontal plane alignment, medial joint space, KL grade, mass, WOMAC scores, unbraced walking speed, trunk, hip and knee joint angles and moments. The OA Assist brace reduced medial joint loading by approximately 0.1 to 0.2 BW or roughly 10%, during stance. This decrease was primarily due to the external brace abduction moment, and not changes in gait dynamics, or muscle forces. The brace effectiveness could be predicted (R. 2. =0.77) by the KL grade, and the magnitude of the hip adduction moment in early stance (unbraced). The brace was more effective for those that had larger hip adduction moments and for those with more severe OA. The valgus knee brace was found to reduce the medial joint contact force by approximately 10% as estimated using a musculoskeletal model. Bracing resulted in a greater reduction in joint contact force for those who had more severe OA while still maintaining a hip adduction moment similar to that of healthy controls

Summary. For injuries to the lower leg or forearm, supplemental support from soft tissue compression (STC) with a splint or brace-like system and combined with external fixation could be done effectively and quickly with a minimal of facilities in the field. Introduction. Soft tissue compression (STC) in functional braces has been shown to provide rigidity and stability for most closed fractures, selected open fractures and can supplement some other forms of fracture fixation. However, soft tissue injuries are compromised in war injuries. This study was designed to evaluate if STC can provide adequate rigidity and stability either with, or without other forms of fixation techniques of simple fractures or bone defects after standardised soft tissue defects. The load was applied either axially or in bending as the bending configuration is more like conditions when positioned on a stretcher in the field. Methods. A simple, oblique fracture was created in 23 cadaveric femurs, 23 tibiae and fibulae, 22 humeri and 22 radii and ulnae of intact limb segments. The weight of each intact limb segment was measured. Cyclic axial loads (12 – 120N) were applied for each progressive condition: intact limb, mid shaft osteotomy, a lateral 1/4 circumferential soft tissue defect, 1/3 circumferential defect and finally, 3 cm bone defect. Limbs were randomly assigned to be stabilised be either plate and screw (PS), intramedullary rod (IR) or external fixation (EF). Testing with and without STC in a brace was performed after each condition. In an additional 36 forearms, bending rigidity was measured using a modular fracture brace with external fixation. The bone and the soft tissue weighed separately and the ratio of soft tissue to bone was calculated. ANOVA multi-variant analysis corrected for multiple comparisons was used to compare the axial rigidity between the different conditions tested. Results. There was no significant difference in axial rigidity for humerus or femoral shaft fractures treated by any of the methods related to the degree of soft tissue damage. Femurs, tibias and humeri with a 3 cm bone defect were best stabilised with IR. Forearms with a 3 cm bone defect were best stabilised with PS. Progressive increase in soft tissue defects did create progressive loss in rigidity in forearms and legs, but the most dramatic loss occurred with the bone defect and ST defect. The rigidity of IR and EF in legs decreased over 50% with bone defect, and about 20% of that was restored with STC. The rigidity of IR and EF in forearms decreased almost 79%, and about 21% of that was restored with STC. The increase in resistance to bending in the forearm was most significantly improved by STC. Discussion/Conclusions. Invasive types of surgical intervention provide the best rigidity to fractures, regardless of the presence of or size of a soft tissue defect. In general, use of PS and IR and application of conventional types of braces to achieve STC is not practical in the field. EF, however, can be applied quickly and easily with a minimal of facilities in the field and can be applied in such a way that no foreign bodies end up in the contaminated wound. For injuries to the leg or forearm, supplemental support from STC with a splint or brace-like system could be effective

Objectives

Whilst gait speed is variable between healthy and injured adults, the extent to which speed alone alters the 3D in vivo knee kinematics has not been fully described. The purpose of this prospective study was to understand better the spatiotemporal and 3D knee kinematic changes induced by slow compared with normal self-selected walking speeds within young healthy adults.

Anatomical descriptions of the lateral retinaculum have been published, but the attachments, name or even existence of its tissue bands and layers are ill-defined. We have examined 35 specimens of the knee. The deep fascia is the most superficial layer and the joint capsule is the deepest. The intermediate layer is the most substantial and consists of derivatives of the iliotibial band and the quadriceps aponeurosis. The longitudinal fibres of the iliotibial band merge with those of the quadriceps aponeurosis adjacent to the patella. These longitudinal fibres are reinforced by superficial arciform fibres and on the deep aspect by transverse fibres of the iliotibial band. The latter are dense and provide attachment of the iliotibial band to the patella and the tendon of vastus lateralis obliquus.

Our study identifies two important new findings which are a constant connection of the deep fascia to the quadriceps tendon superior and lateral to the patella, and, a connection of the deeper transverse fibres to the tendon of vastus lateralis obliquus.