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Duke Orthopaedics
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Wheeless' Textbook of Orthopaedics

Syndesmotic Sprain



- See: Technique of Snydesmotic Fixation

- Discussion:
    - if only
syndesmotic ligaments are divided (w/ fibula & collateral ligaments intact) there will be no widening of mortise or lateral displacement of talus;
    - compressing the fibula and tibia above the ankle elicits tenderness at the syndesmosis, implies injury to the syndesmosis;
    - there is a tendency to suffer inverison sprains of the ankle, and laxity of the lateral colateral ligament may be the most obvious presenting clinical finding;
    - scutinize the radiographs for plastic deformation of the fibula (which would require osteotomy);
    - consider CT scan to confirm the diagnosis;
    - prognosis
            - most patients will be back to playing sports at 6 weeks, but about 1/2 will continue to significant symptoms even at 6 months; (from Gerber, et al (1998))
            - in the study by Nussbaum ED, et al, 60 consecutive collegiate athletes with high ankle symptoms were prospectively evaluated over a 3-year period in an effort to better define this debilitating ankle injury;
            - all athletes included in this study had tenderness over the distal anterior tibiofibular ligament, tenderness proximally along the interosseous membrane, and functional disability;
            - no study subject had a fracture or frank tibia-fibula diastasis;
            - the severity of the sprain was quantified using the interosseous tenderness length;
            - time to return to full competitive activity averaged 13.4 days;
            - number of days missed from competition was statistically related to the interosseous tenderness length (P = 0.0001) and to positive results on the squeeze test (P = 0.03);
            - six of the patients experienced occasional ankle pain and stiffness, 4 patients reported recurrent ankle sprains, and one patient had heterotopic ossification formation.
            - Persistent disability associated with ankle sprains: A prospective examination of an athletic population.           
            - Prospective Evaluation of Syndesmotic Ankle Sprains Without Diastasis   
             

- Exam:
    - the fibula is nestled into a groove on the lateral side of the tibia which makes a stable construct;
    - anterior lip of the tibial groove is prominent while the posterior lip is much less pronounced;
    - often swelling is minimal, which leads to underestimation of the severity of these sprains;
    - squeeze test:
          - clinical test for syndesmotic instability;
          - w/ positive test, compression of the proximal calf causes pain at the distal syndesmosis;
          - anatomically, squeezing the proximal calf will cause separation of the distal fibula and specifically will cause separation of the anterior tibiofibular ligament;
    - fibular drawer test:
          - when attempting to displace the fibula anteriorly in an uninjured ankle, the examiner cannot elicit movement;
          - in a normal ankle the examiner frequently can feel movement when he attempts to displace the fibula posteriorly;
          - rarely can he initiate an increase in anterior displacement of the fibula in pts who have sustained injures to the ligamenotuos structures supporting the syndesmosis;
                 - w/ sprain, the examiner can initiate increase in posterior displacement which usually reproduces pain;
          - coronal drawer test:
                 - talar motion in the coronal plane is another indication of syndesmotic widening;


- Radiographic Signs of Injury
    - when static radiographs are negative, consider stress radiographs in external rotation and abudction;
    - w/ late injury, radiographs may show distal tibiofibular calcification;


- Management:
    - an isolated syndesmotic sprain can be treated non operatively in a non wt bearing cast cast;
    - patients should note that recovery from syndesmotic sprains is much longer than is seen in typical ankle sprains;
    - indications for surgery include concomitant medial sided injury or fibular frx;
    - w/ this injury, repair of the collateral ligaments alone will not completely stabilize the ankle;
    - placing a syndesmosis screw across the joint allows near anatomic healing;
    - two screws may be required for a high syndesmotic sprain



Syndesmotic ankle sprains.

Acute ligamentous diastasis of the ankle without fracture.  Evaluation by radionucleotide imaging.

Ankle diastasis without fracture.

A biomechanical analysis of the squeeze test for spranins of the syndesmotic ligaments of the ankle.

Syndesmosis sprains of the ankle.

Syndesmosis sprains of the ankle. The influence of heterotopic ossification.

Isolated Syndesmosis Ankle Injury



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, December 10, 2012 3:10 pm