It is difficult to determine the safe timing
of weight-bearing or reconstructive surgery in patients with Charcot arthropathy
of the foot and ankle. In this study the Doppler spectrum of the
first dorsal metatarsal artery was used to monitor the activity
of the disease activity and served as a guideline for management.
A total of 15 patients (seven men and eight women) with acute diabetic
Charcot arthropathy of the foot and ankle were immobilised in a non-weight-bearing
cast. They were followed at two-week intervals and bilateral Doppler
spectra of the first dorsal metatarsal arteries were obtained using
a 10 MHz linear ultrasound probe. The patients were allowed to start weight-bearing
or undergo surgery after the Doppler spectrum had returned to normal
pattern. The Doppler spectra in the unaffected limbs were triphasic
in pattern, whereas those in limbs with active Charcot arthropathy
showed monophasic forward flow. They returned to normal after a
mean of 13.6 weeks (6 to 20) of immobilisation. Three patients underwent
pan-talar arthrodesis to correct gross instability and deformity. Doppler spectrum analysis of the foot may reflect the activity
of the disease in patients with Charcot arthropathy, and may be
used as a guide to begin weight-bearing or undergo reconstructive
surgery.
We report an audit of 208 patients with a mean age of 39 years (16 to 65) attending the Orthopaedic Assessment Unit at the Wellington Hospital between January 2006 and December 2007 with an injury of the tendo Achillis requiring immobilisation in a cast. Information on assessment of venous thromboembolism (VTE) risk, prophylactic measures and VTE events for all patients was obtained from the medical records. A VTE risk factor was documented in the records of three (1%) patients. One of the 208 patients received aspirin prophylaxis; none received low molecular weight heparin. In all, 13 patients (6.3%, 95% confidence interval 3.4 to 10.5) developed symptomatic VTE during immobilisation in a cast, including six with a distal deep-vein thrombosis (DVT), four with a proximal DVT, and three with a confirmed pulmonary embolus. This incidence of symptomatic VTE is similar to that reported following elective hip replacement. We propose that consideration is given to VTE prophylaxis during prolonged immobilisation of the lower limbs in a cast, to ensure that the same level of protection is provided as for patients undergoing elective hip replacement.