Assessing the Accuracy and Reliability of the Fluoroscopic Ruler for Comminuted Femur Fractures: A Cadaveric Study.

BACKGROUND: Fixation of comminuted femur fractures may result in limb length discrepancy. Intraoperative fluoroscopic measurement of the contra-lateral femur with a ruler is commonly performed to establish a reference for femoral length. No evidence regarding the reliability and accuracy of this technique exists. This study aimed to assess the accuracy and interrater reliability of a fluoroscopic ruler in obtaining correct femoral length in a comminuted femoral shaft fracture model. MATERIALS AND METHODS: Approximately 5 cm of bone was removed from the left femoral diaphyses of 8 cadavers. Seven orthopedic surgery residents and 2 attendings measured the length of the intact contralateral femur using a ruler under fluoroscopy. The ruler was then applied to the "fractured" femur with manual traction applied until femoral length matched the measured length of the contralateral femur. The resulting gap in the "fractured" femur was compared with the length of bone that had been resected. Data were analyzed using means, SDs, and intraclass correlation coefficients (ICCs). RESULTS: Fifty-seven measurements were collected. The mean difference between the measured fracture gap and the length of bone removed was 8.0±5.8 mm (range, 0-22 mm). Femoral length was accurate to 5 mm in 40% of cases, 10 mm in 70%, 15 mm in 81%, 20 mm in 98%, and 25 mm in 100%. The overall interrater reliability was poor (ICC, 0.11; 95% CI, 0.001-0.44). CONCLUSION: Despite poor interrater reliability, the fluoroscopic ruler resulted in a mean leg length discrepancy of 8.0±5.8 mm in this cadaveric study. [Orthopedics. 202x;4x(x):xx-xx.].

Posterior Cruciate Ligament Injury After Retrograde Nailing of Periprosthetic Distal Femur Fractures: A Report of 2 Cases.

CASE: A 51-year-old man and 64-year-old woman with bilateral cruciate-retaining total knee arthroplasties (CR-TKAs) who sustained unilateral periprosthetic distal femur fractures above their CR-TKA and experienced knee instability secondary to an iatrogenic posterior-cruciate-ligament (posterior cruciate ligament [PCL]) injury from retrograde intramedullary nailing. Both patients recovered knee stability after undergoing revision surgery. CONCLUSION: Many CR-TKA designs have sufficient medial-lateral intercondylar distance to place a retrograde nail, femoral components with a relatively posterior transition from the trochlear groove to the intercondylar box will necessitate a nail starting point closer to the PCL origin. This may contribute to iatrogenic postoperative knee instability for patients with CR-TKA designs.

Intraoperative Dysrhythmias Cease After Venting During Intramedullary Nailing of an Impending Femur Fracture: A Case Report.

CASE: A 76-year-old woman with multiple myeloma and osteoporosis presented with right hip pain and an impending atypical femoral fracture in the setting of chronic bisphosphonate use. After preoperative medical optimization, she was scheduled for prophylactic intramedullary nail fixation. Intraoperatively, the patient experienced episodes of severe bradycardia and asystole associated with intramedullary reaming, which ceased after distal venting of the femur. No additional intraoperative or postoperative complications were encountered, and the patient recovered uneventfully. CONCLUSION: Femoral canal venting may be an appropriate intervention for similar transient dysrhythmias caused by intramedullary reaming.