A principle of Total Knee Arthroplasty (TKA) is to achieve a neutral standing coronal alignment of the limb (Hip Knee Ankle (HKA) angle) to reduce risks of implant loosening, reduce polyethylene wear, and optimise patella tracking. Several long-term studies have questioned this because the relationship between alignment and implant survivorship is weaker than previously reported. We hypothesize standing HKA poorly predicts implant failure because it does not predict dynamic HKA, dynamic adduction moment, and loading of the knee during gait. Therefore, the aim of our study is to assess the relationship between the standing (or static) and the dynamic (gait activity) HKAs. We performed a prospective study on a cohort of 35 patients (35 knees) who were treated with a posterior-stabilized TKA for primary osteoarthritis between November 2012 and January 2013. Three months after surgery each patient had standardized digital full-leg coronal radiographs and was classified as neutrally aligned TKA (17 patients), varus aligned (9 patients), and valgus aligned (4 patients) (figure 1). Patients then performed a gait analysis for level walking and dynamic HKA and adduction moment during the stance phase of gait were measured.Background
Methods
Recent studies have concluded that gender influences hip morphology at the time of surgery as well as dysplastic development of the hip. This may lead to a particular choice of implant including stem design and/or neck modularity. In this study we hypothesized that not only gender but also morphotype and etiology (primary osteoarthritis versus aseptic osteonecrosis) may be a significant factor to predict the anatomy of the hip at the time of total hip arthroplasty (THA). We reviewed 690 patients undergoing THA for primary arthritis (OA) or avascular osteonecrosis (AVN) between April 2000 and June 2005 and stratified each into three groups based on their anatomic constitution: endomorph (EN), ectomorph (ECT), or mesomorph (ME) (determined by the ratio: pelvic width/total leg length measured on full-length X-rays). Two independent observers measured twice four parameters on preoperative CT scan: neck-shaft-angle angle (NSA), femoral offset value (FO), helitorsion (Ht) value and femoral neck anteversion (Av).Introduction:
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