PURPOSE To identify the accuracy of postoperative implant alignment in minimally invasive surgery total knee arthroplasty (MIS-TKA), based on the degree of varus deformity. MATERIALS AND METHODS The research examined 627 cases of MIS-TKA from November 2005 to December 2007. The cases were categorized according to the preoperative degree of varus deformity in the knee joint in order to compare...

Increased conformity at the tibiofemoral articulation increases contact area and reduces contact stresses in total knee arthroplasty. Malalignment, however, can increase polyethylene contact stresses. The effect of knee alignment and articular conformity on contact stresses was evaluated in a finite element model. The polyethylene insert and femoral component were modeled in high- and low-confo...

The purpose of this study was to determine if a horizontal cleavage lesion (HCL) of the posterior horn of the medial meniscus would result in changes to tibiofemoral contact mechanics, as measured by peak contact pressure and contact area, which can lead to cartilage degeneration. To study this, 10 cadaveric knees were tested in a rig where forces were applied (500 N Compression, 100 N shear, 2...

Congenital habitual patellar dislocation is a rare condition of the knee where the patella dislocates during flexion and relocates during extension. The congenital form is permanent, irreducible, and presents at birth. It is characterized by a short quadriceps and a major patellofemoral dysplasia and short height. This article presents a rare case of a 27-year-old woman with recurring bilateral...

BACKGROUND Following anterior cruciate ligament injury and subsequent reconstruction transverse plane tibiofemoral rotation becomes underconstrained and overconstrained, respectively. Conflicting reports exist on how rotations influence loading at the knee. This investigation aimed to determine the mechanical effects of internal and external tibial rotation offsets on knee kinematics and ligame...

Patients with severe varus deformity of the knee (≥15° varus) usually are not considered good candidates for minimally invasive total knee arthroplasty (TKA). The goal of this study was to retrospectively investigate outcomes in patients with severe varus deformity after minimally invasive TKA. A study group of 52 patients with a tibiofemoral mechanical axis of 195° or greater was compared with...

OBJECTIVES Initial stability of tibial trays is crucial for long-term success of total knee arthroplasty (TKA) in both primary and revision settings. Rotating platform (RP) designs reduce torque transfer at the tibiofemoral interface. We asked if this reduced torque transfer in RP designs resulted in subsequently reduced micromotion at the cemented fixation interface between the prosthesis comp...

OBJECTIVE This study tests the hypothesis that the natural progression of osteoarthritis (OA) in human joints leads to an increase in the friction coefficient. This hypothesis is based on the expectation that the wear observed in OA may be exacerbated by higher friction coefficients. A corollary hypothesis is that healthy synovial fluid (SF) may help mitigate the increase in the friction coeffi...

It is well known that the physiological alignment of the lower limbs changes during the first years of life. Mild to moderate bowlegs in newborns and knock-knees in early childhood are well-defined and quite common orthopaedic problems. The established reference values of paediatric lower limb alignment are based on clinical or/and radiographic measurements of the tibiofemoral (TF) angle and th...

PURPOSE To assess the feasibility of high resolution knee cartilage MRI with in situ mechanical loading using optical tracking to compensate for motion. METHODS In vivo cartilage MRI with in situ mechanical loading is demonstrated on a clinical 3T system for the patellofemoral as well as for the tibiofemoral knee joint using a T1-weighted spoiled three-dimensional gradient-echo sequence. Pros...