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Background Dynamic and static varus alignment, both, have been reported as risk factors associated with structural progression of knee osteoarthritis. However the association of none of the static and dynamic alignment with structural, clinical, and functional progression associated with knee osteoarthritis has not been assessed yet in a longitudinal study. Methods Forty-seven women with early and established medial knee osteoarthritis were evaluated. Static and dynamic alignment as well as MRI detected structural features, clinical, and functional characteristics of patients were assessed at baseline and at 2 years follow-up. Associations between baseline static and dynamic alignment with structural, functional, and clinical characteristics at the time of entry, as well as the changes over 2 years were evaluated. Findings Both static and dynamic varus alignment at baseline were significantly associated with osteoarthritis related tibio-femoral joint structural abnormalities detected on MRI, at the time of entry. Only the magnitude of varus thrust at baseline was predictive of the changes in the presence of meniscal maceration over two years. None of the static or dynamic measures of knee joint alignment were associated with clinical characteristics associated with medial knee osteoarthritis. Interpretation The key finding of this study is that both frontal plane dynamic and static alignment, are associated with structural abnormalities in patients with medial knee osteoarthritis.

Increased cyclic compressive loading in the medial compartment of the knee is associated with the progression of knee osteoarthritis (OA). However as medial knee OA is accompanied by a range of neuromuscular, morphological and structural changes throughout the lower limb, a clear consensus of the etiology of the disease is yet to emerge. Of particular recent interest are the roles of non-knee-spanning muscles and the lower-limb kinematic chain in the pathomechanics of knee OA. Joint loads during gait occur due to contributions from all muscles, gravity and inertia. As such the aim of this work was to utilise experimental gait data in conjunction with musculoskeletal modelling to undertake a novel and detailed examination of these individual constituent factors influencing loading in the osteoarthritic knee. Specifically, the objective was to decompose the time-histories of loads in the medial and lateral tibiofemoral compartments of osteoarthritic knees into contributions by individual muscles, gravity and inertia, and to explain the results in light of the known neuro-musculoskeletal changes associated with OA. A novel computational method for decomposing the tibiofemoral compartment loads into contributions by muscles, gravity and inertia was developed and integrated into an advanced musculoskeletal modelling pipeline. Experimental gait data from varus mal-aligned unilateral medial knee OA patients and healthy controls were input into the musculoskeletal modelling pipeline and used to quantify the contributions to the forces and cumulative loads in the medial and lateral compartments of the tibiofemoral-joint, and also to surrogate measures of medial compartment loading. The findings have revealed substantive differences in the composition of joint loads between healthy and osteoarthritic knees, and have explained some of the underlying mechanisms by which elevated knee-joint loads arise in OA patients. Importantly, the findings establish the substantial role play

Restoration of neutral mechanical alignment is one of the prerequisites for long-term TKA survival. This study aimed to investigate the effect of deviations from neutral alignment on bone and implant stress and on ligament strain. Using a previously validated finite element model, a neutrally aligned TKA model was compared to 3 different varus and valgus configurations induced by tibial or by femoral component only and by both component simultaneously. Each model underwent a 2500 N vertical load simulating the peak walking force. Varus and valgus alignment increased polyethylene and bone stress, and altered ligament strains, as compared to the neutral aligned model. Changes in alignment of the tibial component were always associated with more detrimental effects compared to the one of the femoral component., SCOPUS: ar.j, info:eu-repo/semantics/published

A retrospective review was conducted to evaluate the mid-termresults (8.5 years follow-up) of the Varsys ET STETM (Zimmer, Warsaw, Indiana, USA. From 1995 to 2000, 225 total hip arthroplasty (THA) were performed using this device. All patients were evaluated clinically by the Harris Hip Score, and radiographically. The Hip Score increased fron 54 preoperatively to 97 point postoperatively. The stem displayed a varus alignment between 5° and 10° in 17cases without any clinical consequences (HHS 96.8). We recorded one case of septic loosening and one case of aseptic loosening. The stability of the stem was radiographically evaluated according to Engh's criteria, confirming bone ongrowth in all other cases.