Biomedical subjects
Publications and source records attributed to E S Holt.
Fracture of the tibial plafond, such as in a trimalleolar fracture, with a large posterior tibial (posterior malleolus) fragment may require open reduction and internal fixation. Anatomic reduction of the articular surface can be ensured by visualizing the articular surface using an arthroscope during reduction. Four cases wherein this technique has proven effective are described.
Ankle arthrodesis treated by external fixation frequently results in complications from pin tract infections, loss of position, nonunion, and malunion. A method of ankle arthrodesis using 6.5-mm cancellous screws as the primary fixation hardware was developed. The most important screw is placed from the posterior malleolus into the neck and head of the talus, and medial and lateral malleolar screws are added to secure fixation. Near-normal anatomy is maintained with this technique because little or no bone, only cartilage, is removed. Earlier cases were all done through an anterior approach. Later, special techniques were developed for placing screws and strain-relieving bone grafting was added to promote union. Twenty-three cases that were treated by the earlier technique are reviewed. The overall fusion rate was 74%. Three conditions (avascular talus, pyarthrosis, and spasticity) were identified that placed patients at high risk for failure of fusion. Of the patients who were not in a high-risk group, only one had a delayed union. When the high-risk patients were not included in the statistics, the fusion rate was 93%. The evolved technique shows great promise for accurate and trouble-free ankle arthrodesis.
The acetabular depression fracture is defined as a rotated, impacted, osteocartilaginous fragment of the posteromedial acetabulum that occurs in conjunction with a posterior fracture dislocation of the hip. Displacement of this fracture fragment creates incongruity of the posterior acetabular articular surface and the potential for hip joint instability. A retrospective review of hip dislocations over a 3-year period disclosed 75 posterior fracture dislocations of the hip. A total of 71 hips had computerized tomography (CT) scanning after successful closed reduction of the dislocation. Of the 75 dislocations, 58 were treated with open reduction and internal fixation for reproducible posterior subluxation or redislocation upon clinical examination, non-concentric closed reduction, and/or unacceptable articular fracture displacement. The acetabular depression fracture was identified in 17 cases (23%). A total of 16 were found on preoperative CT scans, and one was discovered at the time of open reduction. Preoperatively, each of these injuries demonstrated posterior instability with hip flexion less than 90 degrees. Treatment consisted of disimpaction of the fragment with elevation to the level of the concentrically reduced femoral head. The fragment was stabilized with packed cancellous bone graft obtained from the greater trochanter. The separate posterior lip fragment was then reduced and internally stabilized to ensure reduction of the acetabular depression fragment. We conclude that this variant of the posterior fracture dislocation of the hip occurs in a significant percentage of these injuries. Preoperative recognition of this fracture may correlate with posterior hip instability, and its presence may be an indication for open reduction and internal fixation of the fracture. Long-term studies of this lesion are still needed.
Sheep blood agar containing 23.75 microgram of sulfamethoxazole and 1.25 microgram of trimethoprim (SXT-BA) per ml was compared with conventional sheep blood agar (SBA) for isolating group A and B streptococci from throat cultures. This selective medium allowed much better recovery of group A and B streptococci and suppressed the growth of the normal flora, including "viridans" streptococci. In an initial study of 700 throat cultures, SXT-BA recovered 42% more group A and 49% more group B streptococci than did SBA. When SXT-BA was introduced into the routine microbiology laboratory and used by a number of medical technologists. SXT-BA recovered 28% more group A and 37% more group B streptococci than did SBA. In addition, the selective medium inhibited 83% of the non-group A and B streptococci that were recovered by SBA.