Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A radiographic review of 178 consecutive primary total hip arthroplasties using the AML femoral component with a mean follow up of 40.1 months identified 92.3% to be stabilized by bony ingrowth and 7.7% by fibrous tissue. None were classified as loose. The quality of fit in the isthmus and calcar regions was identified as an important factor in achieving bony ingrowth stabilization. Bony ingrowth was achieved in all age groups with equal frequency. No relationship between sex and the type of stabilization was identified. A clinical correlation utilizing a subset of patients with identical prosthetic components identified equivalent clinical results across all age groups. Thirty-four percent of patients experienced some residual thigh pain. No statistically significant relationship between the presence of thigh pain and the type of femoral component stabilization (bony vs fibrous) could be identified. Ninety-eight percent of patients expressed unconditional satisfaction with their hip replacements.
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PMID:The influence of age, sex, and initial fit on bony ingrowth stabilization with the AML femoral component in primary THA. 160 61

Large joint implants must have immediate fixation to be successful. Unfortunately, the magnitude and consistency of achieving this remains largely unknown. For cementless femoral components it is being increasingly appreciated that torsional loading as occurs during stair climbing or rising from a chair leads to loosening and thigh pain in some cases. A biomechanical test was developed to evaluate fixation in this position. Twelve pairs of human cadaveric femora were press-fit with an AML stem. Each femur was secured in a horizontal position, and the prosthetic head cyclically loaded in a vertically downward direction. The offset of the prosthetic head resulted in a combined torsional and compressive load being applied to the stem within the proximal femur. Loosening was found to consistently occur and rapidly accelerate when the head subsided more than 0.2 mm during 100 cycles. For the AML stem, loosening developed at loads from 62 to 171% of body weight and after as few as 800 cycles. This is within the physiologic range of normal daily activities as measured by others with instrumented prostheses. This poses a challenge to the ability of press-fit stems to tolerate torsional loads in vivo. Patients with a cementless prosthesis should be protected from torsional loading until porous ingrowth and/or bone remodelling have had time to occur. Testing the same stem in paired femora demonstrated no right vs left difference (p greater than 0.6).
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PMID:Loosening of cementless femoral stems: a biomechanical analysis of immediate fixation with loading vertical, femur horizontal. 202 32

A leading problem with cementless hip replacement is thigh pain, probably due to some degree of loosening. This is most pronounced during activities such as stair climbing or getting up from a chair. Our study compares the immediate fixation of three stems in widespread clinical use, using a cadaver test simulation in which the femur was horizontal, and cyclic forces acted vertically downward on the prosthetic head with gradual increments of load. We implanted and tested 18 pairs of femurs, making analyses between stem types by right to left comparisons. We found no statistically significant differences in loosening between cementless AML and PCA prostheses, but cemented stems withstood greater loads than uncemented stems by a factor of five or more.
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PMID:Femoral stem fixation in hip replacement. A biomechanical comparison of cementless and cemented prostheses. 234 42

A retrospective study was undertaken to evaluate the clinical and radiographic outcomes of 74 cementless total hip arthroplasties (THA) in 69 young Chinese patients. The Asian size and MMA AML stems with smoothly tapered tip were used, and the patients were followed up for at least five years. The mean Harris hip score was 45.4 preoperatively and 95.3 at the last follow-up. The incidence of thigh pain was 5.4%, and was related to the short stature of the patient (<160 cm) (P = 0.030). Six patients (6 hips, 8.1%) had acetabular osteolysis in zone 2; reoperation was performed in one patient because of osteolysis and wear of the polyethylene liner. The survival rate of the metal acetabular and femoral components was 100% (95% confidence interval, 0.95-1.0). Primary THA with this AML prosthesis had an acceptable mid-term result in young Chinese patients.
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PMID:Mid-term results using a cementless hip prosthesis in young Chinese patients: a five- to seven-year follow-up study. 1905 Aug 81

The relatively high prevalence of thigh pain and stress shielding associated with the AML porous-coated cementless femoral component led to the development of the Prodigy, a femoral component with more extensive porous-coating and a distal polished bullet tip with medial diaphyseal relief to potentially decrease the flexural rigidity. We prospectively evaluated a cohort of 100 consecutive cementless total hip arthroplasties performed using this device. The minimum followup was 10 years (mean, 11.4 years; range, 10-12 years). At 10-year followup, 69 of the 86 patients (82 hips) were living, 14 patients with 15 hips were deceased, and three patients with three hips were lost to followup. No hips required a stem revision. Two patients (two hips) complained of thigh pain. All hips were bone ingrown. Distal tip radiolucencies and osteolysis occurred in 13 hips (17%) and none, respectively. Twenty-one hips (28%) demonstrated moderate or severe stress shielding. Only further followup will determine if this could be a clinical problem or one with revision surgery. These results encourage the authors to continue using second-generation extensively coated stems in their primary total hip arthroplasty constructs.
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PMID:Second-generation extensively porous-coated THA stems at minimum 10-year followup. 1936 96