- 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.