Question: In patients with ankle fracture, is fixation of the
syndesmosis with the use of two 3.5-mm cortical screws through 1 cortex of the
tibia as effective as the use of one 4.5-mm cortical screw through both tibial
cortices?
Design: Randomized (unclear allocation concealment), unblinded,
controlled study with 3 and 12-month follow-up.
Setting: A university hospital in Oslo, Norway.
Patients: 64 patients (mean age, 42 y; 50% women) who had AO type-C
fractures, pathologic widening of >2 mm of the syndesmosis at
intraoperative testing with a hook after fixation of the fractures, or both.
Follow-up was 97% at 3 months and 100% at 12 months.
Intervention: Patients were allocated to two 3.5-mm tricortical
syndesmosis screws (n = 34) or one 4.5-mm quadricortical syndesmosis screw (n
= 30). The quadricortical screw and 1 tricortical screw was placed 2 to 3 cm
proximal to the ankle joint. The second tricortical screw was placed 1 to 2 cm
proximal to the distal screw. Both groups were treated with 2 to 5 kg of
weight-bearing for 8 weeks. Patients in the tricortical-screw group were
permitted full weight-bearing after 8 weeks; patients in the
quadricortical-screw group were not allowed full weight-bearing until after
the screw was removed (8 to 12 wk).
Main outcome measures: Olerud-Molander Subjective Functional Score
(high score = better functioning), difference in dorsiflexion between
fractured and nonfractured ankle, and clinical and radiographic signs of
healing.
Main results: The overall functional and symptom score was higher in
the tricorticalscrew group than in the quadricortical-screw group at 3 months;
the difference was not statistically significant at 1 year
(Table). Groups did not differ
significantly for the difference in dorsiflexion between fractured and
non-fractured ankles at 3 months or 1 year
(Table). All fractures showed
clinical and radiographic healing within 3 months. Groups did not differ with
regard to complications.
Conclusions: In patients with ankle fractures, the use of two 3.5-mm
cortical screws for fixation of the syndesmosis improved early function and
had similar effectiveness at 1 year to the use of one 4.5-mm cortical
screw.
Given the great variety of treatments described for unstable syndesmosis,
the study by Høiness and Strømsøe helps in the
decision-making process, especially with respect to leaving fixation in place
after healing has occurred. Although Park and colleagues reported that 38.5%
of Weber type-B fractures in their series had syndesmotic
diastasis1, the
number of AO type-B fractures receiving syndesmotic fixation in the current
study was high (29 of 64). The method of determining instability was 2 mm of
syndesmotic displacement radiographically after fixation of the fibula with
stress. Kennedy and
colleagues2 reported
no difference in outcome among 45 patients with low Weber type-C fractures
(i.e., within 5 cm of the tibio-talar joint) regardless of whether they had
syndesmotic fixation, which raises the question of whether syndesmotic
fixation is overtreatment in these borderline cases. In this study, it was not
clear why patients with quadricortical screw fixation must be permitted only
partial weight-bearing until screw removal. Furthermore, tricortical fixation
with a single 3.5- or 4.5-mm screw incorporated into the sideplate or beside
the plate was not examined in this study.
This study clearly supports the use of tricortical screws for syndesmotic
fixation with full weight-bearing at 8 weeks and with no need for routine
removal of syndesmotic fixation unless symptoms occur.
Park JW, Kim SK, Hong JS, Park JH.
Anterior tibiofibular ligament avulsion fracture in weber type B lateral
malleolar fracture. J Trauma.2002;52:
655-9.52655
2002
[PubMed][CrossRef]
Kennedy JG, Soffe KE, Dalla Vedova P,
Stephens MM, O'Brien T, Walsh MG, McManus F. Evaluation of the syndesmotic
screw in low Weber C ankle fractures. J Or thop Trauma.2000;14:
359-66.14359
2000
[PubMed][CrossRef]