In patients with moderate and severe hallux valgus, the results of chevron osteotomy were at least as effective as a scarf osteotomy. Recurrent subluxation of the first metatatarsophalangeal joint was the main cause for insufficient correction. We favor the chevron osteotomy because it is less invasive, without sacrificing correction of HVA and IMA.

No abstract

It is often suggested that patella tracking after total knee arthroplasty (TKA) with an asymmetrical patella groove is more physiological than with a symmetrical patella groove. Therefore, this study tried to address two questions: what is the effect of TKA on patella tracking, and is patella tracking after asymmetrical TKA more physiological than patella tracking after symmetrical TKA? The patellar and tibial kinematics of five cadaveric knee specimens were measured in the intact situation, after the incision and suturing of a zipper, and after placement of a symmetrical TKA and an asymmetrical TKA, respectively. The patellae were not resurfaced. The flexion-extension kinematics were measured with an internal and external tibial moment to determine the envelope of motion (laxity bandwidth) of the tibio-femoral and patello-femoral articulation. The kinematics after TKA showed statistically significant changes in comparison to the intact situation: patellar medio-lateral translation, patellar tilt and tibial rotation were significantly affected. No statistically significant differences in knee kinematics were found between the symmetrical and the asymmetrical TKAs. We conclude that conventional TKA significantly changes physiological patello-femoral kinematics, and TKA with an asymmetrical patella groove does not improve the non-physiological tracking of the patella.

Background: It is recognized that different types of hallux valgus exist. Classification occurs with radiographic and clinical parameters. Severity of different parameters is used in algorithms to choose between different surgical procedures. Because there is no consensus about each parameter nor their cut-off point we conducted this study to analyze the influence of these variables on the postoperative hallux valgus angle.

High-flexion knee replacements have been developed to accommodate a large range of motion (RoM > 1208). Knee implants that allow for higher flexion may be more sensitive to femoral loosening as the knee load is relatively high during deep knee flexion, which could result in an increased failure potential at the implant-cement interface of the femoral component. A 3D finite element knee model was developed including a posterior-stabilized high-flexion knee replacement to analyze the stress state at the femoral implant-cement interface during a full squatting movement (RoM 1558). During deep flexion (RoM > 1208), tensile and shear stress concentrations were found at the implant-cement interface beneath the proximal part of the anterior flange. Particularly, the shear stresses at this interface location increased during high flexion, from a peak stress of 4.03 MPa at 908 to 6.89 MPa at 1408 of flexion. Tensile stresses were substantially lower, having a peak stress of 0.72 MPa at 1008 of flexion. Using data from earlier interface strength experiments, none of the interface beneath the anterior flange was predicted to fail in the normal flexion range (RoM 1208), whereas the prediction increased to 2.2% of the interface during deeper knee flexion. Thigh-calf contact reduced the knee forces, interface load, and failure risk beyond 140-1458 of flexion. Based on the more critical stresses at the femoral fixation site between 1208 and 1458 of flexion, we conclude that the femoral component has a higher risk of loosening at high-flexion angles. Keywords: total knee arthroplasty; high flexion; femoral loosening; finite element analysis; implant-cement interfaceThe traditional goals of total knee arthroplasty (TKA) are pain relief and restoration of normal knee function. Several clinical studies demonstrated that TKA patients receiving a standard knee replacement in general achieve maximal flexion angles limited to roughly 1208 of flexion.1 Hence, active knee patients experience limitations during activities such as squatting and kneeling.2 High-flexion TKAs have been developed to facilitate a larger post-operative range of motion (RoM > 1208). High-flexion implants are mostly based on successful standard designs with the posterior condylar geometry adapted to accommodate increased joint load occurring during deep knee flexion.In a recent follow-up study, Han et al. 3 reported a disturbingly high incidence of early femoral loosening for high-flexion TKA. They observed aseptic femoral loosening in 38% of the operated cases at a mean follow-up of 23 months. Furthermore, the occurrence of loosening was closely related to the maximal flexion angle achieved after TKA. In nearly all cases of loosening, the femoral implant-cement interface debonded, particularly beneath the anterior flange, with radiolucent lines visible on lateral radiographs. Due to this debonding process, the femoral component migrated into a position of increased flexion during deep knee bends. A similar mode of failure was earlier described by King ...