Hip contact stress and femoral neck retroversion: a biomechanical study to evaluate implication of femoroacetabular impingement.

The current literature on femoroacetabular impingement (FAI) is focused on acetabular orientation and femoral head asphericity, with little emphasis on the effect of version of the femoral neck. A biomechanical model was developed to determine the causative effect, if any, of femoral retroversion on hip contact stress and, if present, delineate the type of FAI with femoral neck retroversion. Five pairs of cadaveric hips (n = 10) were tested by loading the hip in 90° of flexion and measured the peak joint pressure and the location of the peak joint pressure.

Porous Tantalum Buttress Augments for Severe Acetabular Posterior Column Deficiency.

In revision total hip arthroplasty (THA), consensus is lacking regarding the optimal method for reconstruction of the most severe acetabular defects. Porous tantalum (TM) buttress augments were designed for the most severe postero-superior defects. The purpose of this study was to report the results of a consecutive series of acetabular reconstructions utilizing TM buttress augments.

Revision TKA for Flexion Instability Improves Patient Reported Outcomes.

Unlabelled: Instability is a major cause of early revision of total knee arthroplasty (TKA), of which flexion instability is a major subset. We analyzed radiologically evident corrections, patient reported outcome and complications associated with revision TKA for flexion instability in a retrospective cohort of 37 patients with minimum one year follow up. Following revision surgery, there was a significant increase in mean posterior condylar offset ratio and a significant decrease in tibial slope while the level of joint line was not significantly altered.

Validity and reliability of radiographic knee osteoarthritis measures by arthroplasty surgeons.

Most orthopedic surgeons do not routinely use radiographic classification systems to grade the extent of joint space narrowing in patients considered for total knee arthroplasty. The authors compared the validity and reliability of radiographic measures of tibiofemoral osteoarthritis by 2 experienced and 2 inexperienced orthopedic surgeons on individuals who subsequently underwent total knee arthroplasty. The Kellgren-Lawrence and the Osteoarthritis Research Society International classification systems were used by all surgeons to score the radiographs in 116 individuals in the Osteoarthritis Initiative, a federally funded cohort study of individuals with or at risk of knee osteoarthritis.

Extent of tibiofemoral osteoarthritis before knee arthroplasty: multicenter data from the osteoarthritis initiative.

Background: Knee arthroplasty traditionally is recommended for persons with substantial disability and disabling pain attributable to moderate or severe osteoarthritis (OA). Pain and functional status after arthroplasty may be influenced by the extent of knee OA before surgery and recent evidence suggests persons with less severe knee OA before undergoing TKA have greater pain levels and worse function than persons with more severe knee OA.

Questions/purposes: We determined the proportion of patients undergoing knee arthroplasty who had less than moderate knee OA before surgery and who had either a radiographically normal medial or lateral joint space before surgery.

Role of the coronoid process in varus osteoarticular stability of the elbow.

The role of the coronoid process in varus osteoarticular stability of the elbow was investigated in 10 cadaveric elbows. Testing was performed at multiple flexion angles after incremental removal of the coronoid. At each flexion angle, removal of more than 50% of the coronoid produced a statistically significant decrease in the load resisting varus displacement compared with all lesser resection levels (P < .