Biomedical subjects
Howard B Yeon
Publications and source records attributed to Howard B Yeon.
Primary total hip arthroplasty with a proximally porous-coated femoral stem.
BACKGROUND: The use of cementless, proximally porous-coated femoral stems for total hip arthroplasty has increased in popularity. The purpose of the present report was to examine the five to ten-year results associated with the use of a so-called second-generation circumferentially proximally porous-coated titanium-alloy stem. METHODS: Between 1991 and 1994, 123 Harris-Galante Multilock femoral stems were implanted in 101 patients. The average age of the patients at the time of surgery was 53.8 years. The patients were followed prospectively and were reevaluated at a minimum of five years postoperatively. No patient was lost to follow-up. Twenty-five patients (thirty hips) were interviewed by telephone, and four patients (five hips) died during the study period because of problems that were unrelated to the operation. The remaining seventy-two patients (eighty-eight hips) had a minimum of five years of clinical and radiographic follow-up. RESULTS: The average duration of follow-up was seventy-eight months. At the time of the most recent follow-up, the average Harris Hip Score was 95 points. Eighty-seven (99%) of eighty-eight stems were biologically stable, with eighty-four hips (95%) having osseous ingrowth and three hips (3%) having stable fibrous fixation. One stem was revised because of loosening. Thirty-three hips (38%) had minimal proximal osteolysis, and no hip had diaphyseal osteolysis. Seventy-two hips (82%) had some degree of stress-shielding in the proximal metaphysis, but only two hips had cortical resorption. None of these patients required additional surgery, and all reported a satisfactory outcome. CONCLUSIONS: Given the young age and high activity level of these patients, this stem fared well: the levels of patient function and satisfaction were high, the rates of loosening and revision were very low, and distal osteolysis did not occur. Osseous fixation occurred reliably. Proximal stress-shielding was seen but did not seem to be clinically important.
Paradoxic cerebral embolism after cemented knee arthroplasty: a report of 2 cases and prophylactic option for subsequent arthroplasty.
Major orthopaedic procedures that involve instrumentation of the medullary canal are well known to produce showers of embolic debris including fat, bone fragments, marrow constituents, and cement. A growing literature has identified paradoxic cerebral embolism as a rare but serious consequence of the passage of these emboli through an intracardiac right-to-left shunt to the cerebral arterial circulation. We report 2 cases of paradoxic cerebral embolism after cemented total knee arthroplasty and propose a novel treatment plan to prevent recurrent stroke during subsequent surgery.