Faculty Bibliography

OBJECTIVES: To compare the pullout strengths of 6.5-millimeter diameter partially threaded cancellous screws and 4.5-millimeter diameter fully-threaded cortical screws versus 3.5-millimeter diameter cortical screws in the proximal tibia. DESIGN: Three screws were inserted in the lateral tibial plateau of each leg of fifteen paired cadaveric tibias. In one tibia, large-fragment fixation was used, consisting of a unicortical 6.5-millimeter screw in the subchondral bone, and bicortical 4.5-millimeter screws in the metadiaphyseal and diaphyseal bone. In the contralateral tibia, small-fragment fixation consisting of three 3.5-millimeter screws was used, placing the screws in the same positions as described above. MAIN OUTCOME MEASUREMENTS: A materials-testing machine was used to determine axial pullout strengths of each screw. The mean pullout strengths of large-fragment and small-fragment screws in each position were compared. RESULTS: No significant difference in pullout strengths was found between the large-fragment and small-fragment screws in subchondral and metadiaphyseal bone. A statistically significant difference was found between pullout strengths of large-fragment and small-fragment screws in diaphyseal bone. CONCLUSIONS: In human proximal tibial bone, the data from this study do not suggest that the pullout strength of 3.5-millimeter screws differs from that of 6.5-millimeter screws in subchondral bone, or that the pullout strength of 3.5-millimeter screws differs from that of 4.5-millimeter screws in metadiaphyseal bone. However, the pullout strength of 3.5-millimeter screws is significantly less than that of 4.5-millimeter screws in diaphyseal bone. The authors of the present study believe this supports the use of small-fragment fixation in the treatment of tibial plateau fractures

Thrombocytopenia-absent radius (TAR) syndrome is defined by bilateral absence of the radius and hypomegakaryocytic thrombocytopenia (<150,000/mm3). Lower extremity and nonorthopaedic anomalies also are frequently present. Charts and radiographs of 23 patients with TAR syndrome were reviewed, with extremity and other anomalies documented. Upper and lower extremity management, which included surgery and multiple attempts at orthotic and prosthetic fitting, was evaluated. Upper extremity prostheses were generally rejected, as most patients were able to perform tasks by approximating themselves closely enough to an object to use their own hands. Adaptive devices for feeding, dressing, and toileting were well tolerated. In the lower extremity, most affected patients either rejected any lower extremity intervention or had involvement that eventually precluded functional ambulation, necessitating power wheelchair or motorized cart use. The greatest degree of independence for these patients comes not from surgical, prosthetic, or orthotic intervention, but from the use of simple adaptive devices and powered mobility aids if required

Measurements of stride length, gait speed, and distance walked during seven days were obtained from 15 postpolio and eight control subjects. Pedometers were used to measure distance walked. Measurements of stride length and speed were performed three times, and there was a high correlation between tests (R = .852-.969). The pedometers failed to record accurately in some postpolio subjects, and these subjects were dropped from analysis when ambulation distance was used as a variable. There were significant differences between the postpolio subjects and controls with respect to gait speed (47.7 +/- 14.0 vs 74.9 +/- 15.9 m/min, p less than 0.0005), stride length (55.3 +/- 11.7 vs 69.8 +/- 8.6 cm, p = .006), and average kilometers walked per day for seven days (1.97 +/- 1.3 vs 3.89 +/- 1.7, p = .016). The postpolio subjects had their serum creatine kinase (CK) levels measured at the end of the study. Forty percent of subjects had a level above the normal limits of our laboratory. There was a significantly positive correlation between CK levels and the distance walked during the previous 24 hours (R = .75, p = .012). The findings of this study illustrate the impact of gait abnormalities on the ambulatory abilities of the postpolio population. The correlation of CK with ambulation supports the association of exercise as a source of elevated CK levels in the postpolio population

Measurements of stride length, gait speed, and distance walked during seven days were obtained from 15 postpolio and eight control subjects. Pedometers were used to measure distance walked. Measurements of stride length and speed were performed three times, and there was a high correlation between tests (R = .852-.969). The pedometers failed to record accurately in some postpolio subjects, and these subjects were dropped from analysis when ambulation distance was used as a variable. There were significant differences between the postpolio subjects and controls with respect to gait speed (47.7 +/- 14.0 vs 74.9 +/- 15.9m/min, p less than 0.0005), stride length (55.3 +/- 11.7 vs 69.8 +/- 8.6cm, p = .006), and average kilometers walked per day for seven days (1.97 +/- 1.3 vs 3.89 +/- 1.7, p = .016). The postpolio subjects had their serum creatine kinase (CK) levels measured at the end of the study. Forty percent of subjects had a level above the normal limits of our laboratory. There was a significantly positive correlation between CK levels and the distance walked during the previous 24 hours (R = .75, p = .012). The findings of this study illustrate the impact of gait abnormalities on the ambulatory abilities of the postpolio population. The correlation of CK with ambulation supports the association of exercise as a source of elevated CK levels in the postpolio population