The Rule of the Ring

  A young woman was transported by EMS with excruciating ankle pain after slipping on the ice. A quick glance at the x-ray clearly shows the reason, but this should raise an additional red flag for EPs.   Always remember the "rule of the ring." The tibia and the fibula are held together by an interosseous ligament to form a ring in the lower leg. Undertake a search for a second abnormality if there is a fracture in the tibia or fibula above the ankle syndesmosis. This x-ray should beget another if you remember the rule of the ring.     This external rotation injury is a Maisonneuve fracture, in which there is:   A spiral fracture of the proximal third of the fibula. A disruption of the interosseous ligament. Another abnormality on the distal tibial side of the leg. The distal tibial injury most commonly affects the ankle joint itself, widening the mortise or creating a medial malleolar fracture. The distal tibial fracture may occur about the level of the syndesmosis in a few cases, however. Regardless, the abnormality triad produces an unstable fracture usually requiring ORIF.   I have been shocked by quite a few patients in the past who had significant pain in the ankle but never complained of knee pain, even on re-evaluation after the images were reviewed. Maintain a high index of suspicion with documented injuries despite the clinical exam of the knee.   Tips to Remember: Remember the rule of the ring. A distal tibia fracture or mortise widening should ...
Source: Lions and Tigers and Bears - Category: Emergency Medicine Tags: Blog Posts Source Type: blogs