This study provides evidence that the implant alignment with computer-assisted total knee arthroplasty, as measured with radiography and computed tomography, is significantly improved compared with that associated with conventional surgery with intramedullary or extramedullary guides. This finding adds to the body of evidence showing an improved radiographic outcome with computer-assisted surgery compared with that following conventional total knee arthroplasty.

Femoroplasty, the augmentation of the proximal femur, has been shown in biomechanical studies to increase the energy required to produce a fracture and therefore may reduce the risk of such injuries. The purpose of our study was to test the hypotheses that: (1) 15 mL of cement was sufficient to mechanically augment the proximal femur, (2) there was no difference in augmentation effect between cement placement in the intertrochanteric region and in the femoral neck, and (3) cement placement in the femoral neck would predispose the proximal femur to an intertrochanteric fracture, whereas trochanteric placement would result in subtrochanteric fractures. In each of 18 pairs of osteoporotic human cadaveric femora, 15 mL of polymethylmethacrylate bone cement was injected into the trochanteric or femoral neck region of 1 femur, and the noninjected femur was used as the control. The augmentation effect of femoroplasty was evaluated under simulated fall conditions using a materials testing machine. Multiple linear regressions incorporating random effects were used to check for associations between covariates (bone mineral density, cement location, and treatment) and the parameters of interest (stiffness, yield energy, yield load, ultimate load, and ultimate energy). Significance was set at P < .05. It was found that femoroplasty with 15 mL of cement did not significantly increase stiffness, yield energy, yield load, ultimate load, or ultimate energy relative to paired controls. There were no significant differences in parameters of interest or fracture patterns in specimens augmented in the femoral neck versus the trochanter. It was concluded that 15 mL of cement was not sufficient to augment the proximal femur and that there was no biomechanical advantage to the placement of cement within the femoral neck versus the trochanter.

Compressive and quadriceps forces contribute to noncontact ACL injury and should be taken into account when developing ACL injury prevention programs and rehabilitation after ACL reconstruction.

All 3 fixation methods resulted acutely in motion similar to that of the intact pelvis. Although motion increased as a function of cyclical loading, no significant differences were found between fixation methods. All 3 repair methods reduced fracture site motion, but clinical studies are needed to determine if each method relieves pain and provides sufficient fixation for fracture healing.