Failure of exchange reamed intramedullary nails for ununited femoral shaft fractures.

OBJECTIVE: To determine the effectiveness of exchange reamed nails for treatment of aseptic femoral delayed unions and nonunions. DESIGN: Retrospective chart review. PATIENTS: Nineteen patients admitted to the Carolinas Medical Center Level I trauma center from 1990 to 1996 for repair of femoral shaft fracture nonunion following contemporary locked nailing performed at least six months previously. These patients showed no radiographic evidence of progression of fracture healing for three months and had clinical symptoms of nonunion. INTERVENTION: Exchange reamed nails to treat ununited femoral shaft fracture. MAIN OUTCOME MEASUREMENTS: Radiographic and clinical evidence of union of the fracture or of the necessity for additional procedures. RESULTS: In 53 percent of the patients the secondary procedure resulted in fracture union, whereas in 47 percent, one or more additional procedures were required. Eight of the nine fractures that did not unite with exchange nailing united after a subsequent procedure (bone grafting, compression plating, or nail dynamization). Neither the type of nonunion, the location of the shaft fracture, the use of static versus dynamic cross-locking, nor the use of tobacco products was statistically predictive of the need for additional procedures. CONCLUSIONS: Reevaluation of routine exchange nailing as the recommended treatment for aseptic femoral delayed union or nonunion may be required. A significant number of patients who undergo reamed exchange nailing will require additional procedures to achieve fracture healing.

Pulmonary gas exchange during intramedullary fixation of femoral shaft fractures.

BACKGROUND: This study was undertaken to determine if the alveolar dead space fraction (Vd/Vt) or the alveolar-arterial oxygen gradient (A-a DO2) increased during intramedullary fixation of femoral shaft fractures. METHODS: Fifty hemodynamically stable patients with femur fractures were prospectively enrolled. Three serial measurements of Vd/Vt and A-a DO2 were obtained immediately before femoral nailing (Pre), 30 minutes after nailing (+30), and 120 minutes after nailing (+120). Vd/Vt was determined by simultaneously measuring PaCO2 and the steady-state end-tidal CO2 (PetCO2), where Vd/Vt = (1 - PetCO2/PaCO2). RESULTS: Vd/Vt before nailing was 0.09 +/- 0.09 (mean +/- SD); at +30 and +120, Vd/Vt was 0.10 +/- 0.06 and 0.08 +/- 0.07, respectively (p > 0.2; paired t test, both time points). A-a DO2 before nailing was 84 +/- 85 mm Hg, and it did not change significantly at +30 (89 +/- 69 mm Hg; p = 0.51 vs. Pre; paired t-test) or at +120 (51 +/- 45 mm Hg). No difference in data was found with analysis by fracture classification or number of reamer passes. Vd/Vt and A-a DO2, however, were both significantly increased in patients with lung contusion (n = 6) before nailing, but neither measurement increased after nailing. One patient developed fat embolism (Vd/Vt of 0.35 at Pre and 0.31 at +120), and another patient experienced postoperative pulmonary thromboembolism (Vd/Vt increased from 0.06 at Pre to 0.17 at +120). CONCLUSION: The process of femoral nailing does not cause enough pulmonary embolization to alter pulmonary gas exchange as measured by Vd/Vt and A-a DO2. If Vd/Vt is increased preoperatively, the likelihood of subsequent pulmonary dysfunction secondary to either preoperative lung injury or fat embolism is increased.

Popliteus function in ACL-deficient patients.

Anterior cruciate ligament (ACL) injuries commonly result in anterolateral rotary instability and a 'pivot shift' phenomenon. Since popliteus muscle stimulation causes a pivot shift, some postulate the popliteus muscle plays a role in causing pivot shifts. To see if patients with pivot shifts exhibited excessive popliteus muscle activity, we studied fine-wire EMGs of the popliteus in 16 normal subjects and 10 ACL-deficient subjects. Subjects performed six activities (level walking and jogging, ascending walking and jogging, and descending walking and jogging). Except for minor timing differences in ascending treadmill and ascending jogging, the signals were similar for injured and uninjured limbs; similar variance ratios suggested similar pattern variability. Thus, we observed only minor popliteus EMG signal differences in this group of patients. We conclude that the popliteus muscle does not actively contribute to instability in the studied activities.

Analysis of cryotherapy penetration: a comparison of the plaster cast, synthetic cast, Ace wrap dressing, and Robert-Jones dressing.

Four groups were studied to determine the cooling effect at skin level of ice application over common ankle bandages and casts. The plaster cast, synthetic cast, and Ace wrap dressing groups had 18 participants and the Robert-Jones dressing group had four participants. In a standardized fashion, ice bags were applied over each bandage or cast and skin temperatures were measured with a thermocouple over a 90-min period. The average final skin temperature was 16.5 degrees in the plaster cast, 18.8 degrees in the synthetic cast, 21.2 degrees in the Ace wrap dressing, and 28.7 degrees in the Robert-Jones dressing. The temperature curves showed that ice application effectively decreased skin temperatures through the plaster cast, synthetic cast, and Ace wrap dressing. The cooler temperature did not adequately penetrate the Robert-Jones dressing.

Popliteus function in ACL-deficient patients.

Anterior cruciate ligament (ACL) injuries commonly result in anterolateral instability, resulting in a "pivot shift" phenomenon. Given that popliteus muscle stimulation results in a pivot shift, others have postulated that the popliteus muscle has a role in the pivot shift phenomenon. We hypothesized that patients with instability from ACL injuries may have excessive popliteus muscle activity. Therefore, we studied the EMG activity (using fine wire electrodes) of the popliteus muscle in sixteen normal subjects and ten ACL-deficient subjects. We recorded the EMG in six activities (level walking and jogging, ascending walking and jogging, and descending walking and jogging). Person's Product Moment Correlations were above 0.7, except in the case of ascending the treadmill (r = 0.427) and ascending jogging (r = 0.645), suggesting that the timing of the signals was similar for injured and uninjured limbs. Variance ratios for the injured and uninjured limbs were statistically similar, suggesting similar variability of patterns. Thus, we observed only minor popliteus EMG signal differences in this group of patients. We conclude that the popliteus muscle does not contribute to instability in the studied activities.