Biomedical subjects

Kenneth A Krackow

Publications and source records attributed to Kenneth A Krackow.

23 records · Page 2Linked to original sources

PubMed2002

Reliability and validity of a new caliper for measuring patellar thickness.

The process of patellar resurfacing during total knee arthroplasty involves measuring patellar thickness. The optimal residual patellar bone thickness has been questioned. The surgeon's ability to measure patellar thickness currently rests on a standard caliper. Standard methods involve use of a smooth-mouthed caliper, which can overestimate patellar thickness because of soft tissue interposition. This brief communication introduces a new spiked caliper design that can be used to measure patellar bone thickness more accurately. Improved accuracy in measuring patellar bone thickness allows the operating surgeon to assess more correctly a patient's patellar bony status. This knowledge may result in fewer postoperative fracture complications resulting from deficiencies of bone owing to excessive resection.

Arthroplasty, Replacement, Knee↗

PubMed2002

A radiographic study of the detection limits of bone-cement remnants in total joint arthroplasty.

Management of an infected hip prosthesis typically requires that all associated cement be removed. In the absence of gross mantle loosening, the surgeon frequently resorts to intraoperative radiographs to assess the completeness of removal. For this reason, we undertook a study to determine limits of detection of retained cement by routine radiography. Polymethyl methacrylate bone-cement beads (Simplex-P; Stryker-Howmedica-Osteonics, Allendale, NJ) were fashioned into graduated sizes and placed within cadaver medullary canals using 2 different methods. Standard radiographic images were obtained. Individually and independently, we viewed these images and proposed the limit of resolution to be 2.4 to 3.2 mm. It is difficult to remove all cement based on radiographs alone. These results suggest a need to use techniques that permit visualization of the canal to ensure adequate cement removal.

Arthroplasty, Replacement, Hip↗

PubMed2002

Revision total knee replacement ligament balancing for deformity.

Ligament balancing in revision settings requires attention to flexion-extension gap balancing and adjusting the asymmetry of the gaps. The tension-stress examination must be understood and done. The shortcomings of ligament tightening procedures have been experienced. Standard concave-side releases may be done, with attention given to the maintenance of adequate vascularity to the subjacent bone. However, frequently exact and sufficient balance may not be achievable, and resorting to varus-valgus constraint will be necessary. Particular emphasis has been given to the issue of controlling the flexion space and the possibility of losing that control. In the situation of loss of collateral integrity possibly exaggerated by the loss of posterior capsular integrity, one sees a gross enlargement of the flexion space. Addressing this with placement of a thicker tibial component simply leads to great flexion contracture. The larger flexion space may provide the opportunity for subluxation of the intercondylar peg of a varus-valgus constrained prosthesis. Although quadriceps tension may hold the tibia up and control the flexion space, this mechanism of stabilization will fail if the patient's knee regains substantial range of motion.

Aged↗

PubMed2002

Preoperative administration of epoetin alfa to total joint arthroplasty patients.

Epoetin alfa is indicated to reduce allogeneic transfusions in patients undergoing major operations. This study included 40 patients undergoing total joint arthroplasty who received 600 IU/kg doses of epoetin alfa 21, 14, and 7 days preoperatively. Statistically equal matches were obtained according to preoperative hemoglobin, operation, sex, and age. After controlling for autologous donation, the average hemoglobin level on postoperative day one in the treatment group (10.93 g/dL) was significantly higher than the matched patient group (9.86 g/dL). Likewise, treated patients were transfused with significantly less blood (0.68 units/patient) compared to the matched group (1.6 units/patient). In these patients, administration of epoetin alfa was associated with significantly higher perioperative hemoglobin levels and significantly fewer transfusions than matched counterparts. The use of epoetin alfa in this heterogeneous surgical population illustrates its success in a varied population.

Aged↗

PubMedDate not supplied

Total knee arthroplasty in the valgus knee.

The valgus knee presents a unique set of problems that must be addressed during total knee arthroplasty. Both bone and soft-tissue deformities complicate restoration of proper alignment, positioning of components, and attainment of joint stability. The variables that may need to be addressed include lateral femoral condyle or tibial plateau deficiencies secondary to developmental abnormalities, and/or wear; primary or acquired contracture of the lateral capsular and ligamentous structures; and, occasionally, laxity of the medial collateral ligament. Understanding the specific pathologic anatomy associated with the valgus knee is a prerequisite to selecting the proper surgical method to optimize component position and restore soft-tissue balance.

Arthroplasty, Replacement, Knee↗