Ruptured Baker's cyst: complications due to misdiagnosis.

Deep vein thrombosis (DVT) and ruptured Baker's cyst have similar clinical presentations: inflammation and acute pain in the calf. Differential diagnosis is necessary and requires information from Doppler ultrasound imaging because treating suspected DVT with therapeutic doses of low molecular weight heparins (LMWHs) can cause major bleeding and worsen the prognosis of complicated Baker's cyst. We present a series of 7 consecutive cases in which the patients were misdiagnosed with DVT without imaging. LMWHs were started at therapeutic doses in all cases. The patients' symptoms worsened abruptly after treatment, causing compartment syndrome in the leg. Four of the patients required urgent fasciotomy.