Bone Ingrowth into Porous Coated Canine Total Hip Replacements. Quantification by Backscattered Scanning Electron Microscopy and Image Analysis

Bone ingrowth into titanium fiber mesh porous-surfaced canine total hip replacement prostheses was evaluated and quantified using a computer assisted image analysis system attached to a scanning electron microscope equipped with a back scattered electron detector. Excellent contrast between the bone, the porous metal and the soft tissues resulted in the backscatter mode, allowing easy differentiation of these components in real time by the image analysis based on gray scales. By three weeks the mean (± standard deviation) amount of bone ingrowth expressed as a percentage of porous layer measured 7.2% (± 1.5%) for the acetabular components, and 3.9% (± 1.7%) for the femoral components. At six weeks the amount of bone ingrowth increased to 10.5% (± 1.3%) for the acetabular components and 8.5% (± 1.4%) for the femoral components. Cementless prosthetic fixation using porous surfaced prostheses holds great promise in joint replacement surgery, and the ability to quantitate the amount of bone ingrowth will permit the evaluation of the efficacy of various techniques to improve bone ingrowth

Minimal stress shielding with a Mallory-Head titanium femoral stem with proximal porous coating in total hip arthroplasty

<p>Abstract</p> <p>Background</p> <p>As longevity of cementless femoral components enters the third decade, concerns arise with long-term effects of fixation mode on femoral bone morphology. We examined the long-term consequences on femoral remodeling following total hip arthroplasty with a porous plasma-sprayed tapered titanium stem.</p> <p>Methods</p> <p>Clinical data and radiographs were reviewed from a single center for 97 randomly selected cases implanted with the Mallory-Head Porous femoral component during primary total hip arthroplasty. Measurements were taken from preoperative and long-term follow-up radiographs averaging 14 years postoperative. Average changes in the proximal, middle and diaphyseal zones were determined.</p> <p>Results</p> <p>On anteroposterior radiographs, the proximal cortical thickness was unchanged medially and the lateral zone increased 1.3%. Middle cortical thickness increased 4.3% medially and 1.2% laterally. Distal cortical thickness increased 9.6% medially and 1.9% laterally. Using the anteroposterior radiographs, canal fill at 100 mm did not correlate with bony changes at any level (Spearman's rank correlation coefficient of -0.18, 0.05, and 0.00; p value = 0.09, 0.67, 0.97). On lateral radiographs, the proximal cortical thickness increased 1.5% medially and 0.98% laterally. Middle cortical thickness increased 2.4% medially and 1.3% laterally. Distal cortical thickness increased 3.5% medially and 2.1% laterally. From lateral radiographs, canal fill at 100 mm correlated with bony hypertrophy at the proximal, mid-level, and distal femur (Spearman's rank correlation coefficient of 0.85, 0.33, and 0.28, respectively; p value = 0.001, 0.016, and 0.01, respectively).</p> <p>Conclusion</p> <p>Stress shielding is minimized with the Mallory-Head titanium tapered femoral stem with circumferential proximal plasma-sprayed coating in well-fixed and well-functioning total hip arthroplasty. Additionally, the majority of femora demonstrated increased cortical thickness in all zones around the stem prosthesis. Level of Evidence: Therapeutic Level III.</p

Surgeons’ Attitudes Are Associated With Reoperation and Readmission Rates

BACKGROUND: Attitudes influence how people make decisions. In an effort to decrease pilot judgment-related accidents, the Federal Aviation Administration teaches new pilots about hazardous attitudes that are believed to be incompatible with safe flight: macho, impulsive, worry, resignation, self-confidence, and antiauthority. If these attitudes are hazardous for pilots and their passengers, they may also be incompatible with the reliable and safe delivery of surgical care. QUESTIONS/PURPOSES: The purposes of this study were (1) to ascertain to what extent surgeons harbor hazardous attitudes; and (2) to determine their relationship, if any, to reoperation and readmission rates. METHODS: We selected validated aviation psychology tools that are used to measure these attitudes in pilots. We converted the aviation scenarios to analogous situations for surgeons and invited all surgeons from one academic program to participate in this study. A total of 41 surgeons were eligible to participate; 37 (90%) completed the attitude prevalence protocol and 31 (76%) had complete reoperation and readmission data for the correlation and regression analysis. Attending orthopaedic surgeons completed the Modified Surgeon Hazardous Attitude Scale as well as a series of additional instruments. RESULTS: Levels of macho thought to be hazardous in pilots were present in nine (24%) surgeons. Similar, elevated levels of self-confidence were found in three (8%) surgeons. High levels of impulsivity were found in 5% (two surgeons) and high levels of antiauthority were found in 3% (one surgeon). Only one (3%) surgeon reported elevated levels of worry and no surgeon reported hazardous levels of resignation. Thirty percent (11 surgeons) of surgeons harbored at least one elevated attitude level. In a regression model, macho attitude levels predicted 19% of the variation in surgeons’ rate of readmissions and reoperations. CONCLUSIONS: High levels of hazardous attitudes may not be consistent with the routine delivery of safe surgical care in a teamwork setting where human factors and safe systems are the key to success. Further research is needed to determine if abnormally high levels of these hazardous attitudes impact patient care. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11999-014-3687-6) contains supplementary material, which is available to authorized users