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Biomedical subjects

Amir A Jamali

Publications and source records attributed to Amir A Jamali.

8 recordsLinked to original sources
PubMed2006

The effect of surface finish and of vertical ribs on the stability of a cemented femoral stem: an in vitro stair climbing test.

The search for improved femoral fixation in cemented total hip arthroplasty is ongoing. Two design variables, surface finish and stem contour, were evaluated. Sixteen titanium femoral stems of one design were cemented into fiberglass femora. One half of the components had a polished surface and the rest had a roughened finish. Within each group, 4 stems had vertically oriented ribs on the proximal portion and 4 did not. Micromotion was measured in a stair climbing simulator with loading to a joint reaction force of 200 kg for 6 million cycles. Micromotion increased throughout the course of the experiment. Stems with a polished surface had significantly higher micromotion. Although stems with ribs had less micromotion compared with those without ribs, this difference was not statistically significant.

Analysis of Variance↗
PubMed2006

Muscle versus nonmuscle flaps in the reconstruction of chronic osteomyelitis defects.

BACKGROUND: Surgical treatment of chronic osteomyelitis requires aggressive debridement followed by wound coverage and obliteration of dead space with vascularized tissue. Controversy remains as to the effectiveness of different tissue types in achieving these goals and in the eradication of disease. METHODS: Chronic osteomyelitis was induced in 26 goat tibias using Staphylococcus aureus as an infecting inoculum. In a single stage, debridement followed by reconstruction using either a muscle flap (n = 13) or a fasciocutaneous flap (n = 13) was performed. Flap donor sites were closed primarily and antibiotics were given for 5 days postoperatively. Daily clinical evaluation for 1 year was performed and monthly radiographs were obtained for 9 months and 1 year after the reconstruction. RESULTS: Twenty-five flaps survived completely, and one nonmuscle flap underwent partial flap loss following a period of venous congestion. There were no postoperative complications in the muscle flap group. Two goats (15 percent) in the nonmuscle group developed superficial wounds in the immediate postoperative period that resolved with conservative management. No limbs had recurrent osteomyelitis wounds at 1 year of clinical follow-up examination. Radiographic evidence of osteomyelitis was present in two goats (15 percent) in the muscle group and one goat (8 percent) in the nonmuscle group. There was no statistically significant difference in the incidence of recurrent osteomyelitis between the groups by clinical and radiographic assessment. CONCLUSIONS: The findings in this study demonstrate that vascularized tissue flaps in the form of muscle or nonmuscle flaps provide viable options for wound coverage of osteomyelitis defects following adequate surgical debridement.

Animals↗
PubMed2005

A model for chronic osteomyelitis using Staphylococcus aureus in goats.

Animal models of osteomyelitis traditionally have been characterized by inherent weaknesses related to animal size, differences in clinical findings compared with humans, aggressive behavior, high complication rate, and high cost. In this experiment, a model of tibial osteomyelitis was established in 28 goats with a very low complication rate and a consistent clinical, radiographic, and histologic disease course. The infecting Staphylococcus aureus organism was isolated in all but five of 28 animals (82%), in which there was no growth of bacteria at 24 and 72 hours. All five of these specimens had histologic evidence of osteomyelitis. Twenty-seven of the 28 animals (96%) had radiographic and histologic evidence of osteomyelitis. Clinical progression of the disease was observed by draining wounds, a postoperative limp that subsided in all goats, and varied periods of anorexia despite an average increase in body weight. There were no complications or mortalities related to the establishment of the animal model. This large animal model will provide a practical method of studying osteomyelitis and comparing treatment protocols.

Animals↗
PubMed2005

Fresh osteochondral allografts: results in the patellofemoral joint.

UNLABELLED: Twenty knees in 18 patients were treated (mean age, 42 years; range, 19-64 years) with fresh osteochondral allografting limited to the patellofemoral joint. The knees were analyzed retrospectively to determine the rate of successful outcomes. The trochlea and patella were treated in 12 patients and the patella was treated in eight patients. There were 11 women and seven men. The primary outcome measures were revision allografting, arthrodesis, or arthroplasty, and clinical scoring using a modified Merle D'Aubigné-Postel 18-point scale. Radiographs were available for 12 knees. There were five failures. For the remaining knees, the clinical scores increased from a mean of 11.7 points (range, 7-15 points) to 16.3 points (range, 12-18 points). Of the knees evaluated radiographically, four had no evidence of patellofemoral arthrosis, and six had only mild arthrosis. Fresh osteochondral allografting is a salvage procedure for the young, active patient with severe articular cartilage disease of the patellofemoral joint. The results of this procedure are comparable to results of described other techniques in the literature. If allograft incorporation does occur, the procedure is associated with improved pain, function, range of motion, and a low risk of progressive arthritis. LEVEL OF EVIDENCE: Level IV (case series--no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Adult↗
PubMed2004

Isolated acetabular revision with use of the Harris-Galante Cementless Component. Study with intermediate-term follow-up.

BACKGROUND: Isolated revision of an acetabular total hip component is associated with special problems related to the retention of the femoral component. We reviewed the intermediate-term results of a series of such operations with use of the Harris-Galante Porous acetabular component. METHODS: We retrospectively studied the results of ninety-five isolated acetabular revisions, specifically focusing on sixty-three that had been followed for a minimum of sixty months (average, 130 months). Evaluation measures included the Harris hip score, radiographic analysis, complications, and prosthetic survival. Follow-up information was obtained with self-administered questionnaires, telephone contact, and/or clinical examination. The effects of a femoral component with a modular neck-head junction and of trochanteric osteotomy on the dislocation rate were evaluated. RESULTS: Nine shells were rerevised: four because of recurrent dislocation, four because of aseptic loosening, and one because of dissociation of the liner. The survival rate with rerevision of the shell as the end point was 90.5% at 120 months. Pelvic osteolysis occurred in 4% of the cases. The dislocation rate for the sixty-three hips was 8%. When femoral component modularity was accounted for, the analysis of the dislocations revealed a significantly higher dislocation rate for the hips without a trochanteric osteotomy (p = 0.04). Eight arthroplasties were complicated by nerve palsies, seven of which resolved fully or nearly so. CONCLUSIONS: Isolated acetabular revision with use of the Harris-Galante Porous acetabular component was associated with a low rate of loosening, lysis, and rerevision of the shell at the time of intermediate-term follow-up. However, there was a high rate of complications, including trochanteric nonunion, dislocation, and nerve palsy. The performance of a trochanteric osteotomy was associated with a decreased rate of dislocation.

Adult↗
PubMed2002

Differential expression of neural cell adhesion molecule (NCAM) after tenotomy in rabbit skeletal muscle.

Tenotomy is a commonly encountered event in orthopaedic surgery. In 23 rabbit extensor digitorum longus (EDL) muscles, within 24 h after tenotomy, a marked drop in maximum force production occurred. This was not explainable based on architectural changes and histological examination using standard markers for muscle injury, i.e., haematoxylin and eosin morphology, developmental myosin heavy chain (MHC) immunolabeling, and quantitation of muscle fiber type percentage, area and distribution. The expression of neural cell adhesion molecule (NCAM), a glycoprotein expressed during muscle development was measured as a function of time in these muscles. NCAM expression was increased as early as one day after tenotomy with 2.2+/-1.2% of the fibers showing positive expression. This expression level increased significantly to 15.4+/-15.2% after 7 days and then subsided to 13.2+/-10.6% 21 days after tenotomy. Two-way analysis of variance demonstrated a significant effect of time and a significant time x tenotomy method interaction. These results suggest that tenotomy leads to possible changes in muscle-nerve connections and/or excitation-contraction (EC) coupling.

Animals↗