BACKGROUND Stair-stepping motion is important in daily living, similar to gait. Knee prostheses need to have even more superior performance and stability in stair-stepping motion than in gait. The purpose of this analysis was to estimate in vivo knee motion in stair stepping and determine if this unique knee prosthesis function as designed. METHODS A total of 20 patients with Bi-Surface poste...

Context: Although kinematic analyses are helpful in describing movement differences between genders, kinetic data might further explain the predisposing factors contributing to potential injury during athletic landing maneuvers. Objective: To determine whether there are differences in knee moments between male and female varsity college soccer players during a single-leg landing. Design: Preexp...

BACKGROUND Computer navigation systems generally establish the rotational alignment axis of the femoral component on the basis of user-defined anatomic landmarks. However, navigation systems can also record knee kinematics and average alignment axes established with multiple techniques. We hypothesized that establishing femoral rotational alignment with the use of kinematic techniques is more a...

PURPOSE To examine whether normalized quadriceps and hamstring strength would predict quadriceps and hamstring muscle activation amplitudes and whether these neuromuscular factors would predict knee kinematics and kinetics during a drop jump task. METHODS Thirty-nine females and 39 males were measured for isometric quadriceps and hamstring strength and were instrumented to obtain surface elec...

OBJECTIVES The assessment of spinal reflexes has traditionally been performed by clinicians with minimal need for recording equipment, where doctors rely on their training and may use established subjective reflex rating scales. With advances in technology, it is now possible to assess reflexes objectively. This study compared two objective methods of assessing patellar reflex magnitude, durati...

Higher side-to-side asymmetry among female athletes compared to their male counterparts during bilateral athletic tasks such as landing from a jump has been proposed as a potential source of non-contact knee injuries. However, the kinematic symmetry and potential sex differences during bilateral landings have not been examined. The purpose of this study was to evaluate lower extremity kinematic...

Mechanical alignment with conventional total knee arthroplasty (TKA) instruments often requires collateral ligament releases, which result in a high prevalence of adduction and reverse axial rotation (external rotation) of the tibial component during knee flexion with a variety of component designs. We used a radiographic image-matching technique to determine the contact kinematics during stand...

Bicruciate-stabilised total knee replacement (TKR) aims to restore normal kinematics by replicating the function of both cruciate ligaments. We performed a prospective, randomised controlled trial in which bicruciate- and posterior-stabilised TKRs were implanted in 13 and 15 osteo-arthritic knees, respectively. The mean age of the bicruciate-stabilised group was 63.9 years (SD 10.00) and that o...

BACKGROUND A sit-to-stand (STS) movement requires muscle strength higher than that of other daily activities. There are many elderly people, who experience difficulty when standing up from a chair. The muscle strength required (or the load on the joints) during a STS task is determined by the kinematics (movement pattern). The purpose of this study was to evaluate the kinematics and resultant j...