Risk of Deep Vein Thrombosis After Acute Achilles Tendon Rupture A Secondary Analysis of a Randomized Controlled Trial Comparing Early Controlled Motion of the Ankle Versus Immobilization
The incidence of deep vein thrombosis (DVT) in the treatment of acute Achilles tendon rupture is reported to be between 0.3% and 50%. Acute Achilles tendon rupture has an incidence of 20 to 32 per 100,000 individuals per year. Immobilization of the ankle joint has been suggested as a key element in the pathogenesis leading to DVT, and intermittent pneumatic compression has been highly effective in reducing the incidence of DVT in patients with acute Achilles tendon rupture. In treatment of Achilles tendon rupture some use immobilization of the ankle joint for 6 to 10 weeks, while others use early controlled motion (ECM) of the ankle joint. The question is whether ECM of the ankle reduces the incidence of DVT and whether DVT negatively affects outcome after acute Achilles tendon rupture. The primary objective of this study was to investigate whether ECM of the ankle joint in weeks 3 through 8 would reduce the incidence of DVT in patients with acute Achilles tendon rupture, compared with a treatment protocol where the ankle joint was immobilized for 8 weeks. Patients were treated non-operatively, and full weight-bearing was allowed from day 14 in both groups.
A second objective was to determine the impact of DVT on outcomes after nonoperative treatment of acute Achilles tendon ruptures.
How and Who:
The study was performed as a secondary analysis of a randomized controlled trial (RCT) with patients allocated in a 1:1 ratio to 1 of 2 parallel groups. Participants were patients treated for acute Achilles tendon rupture at Copenhagen University Hospital Hvidovre who were age 18 to 70 years.
Patients were treated with a posterior plaster splint in approximately 30 of plantarflexion (evaluated visually) and were referred for an appointment in the outpatient clinic within 4 days. In the outpatient clinic, a below-knee full synthetic cast was applied in approximately 30 (evaluated visually) of plantar-flexion. No weight-bearing was allowed for the first 2 weeks after injury. After 2 weeks, the cast was removed. Each patient was placed in an Aircast AirSelect Standard orthosis (DJO LLC) with 2 wedges that each provided 1.5 cm of heel lift. Full weight-bearing was allowed, but patients were advised to use the crutches for another 1 or 2 weeks. At this point, patients were randomized into 1 of 2 groups:
1. Early controlled motion (ECM): The patient was instructed to perform early controlled ankle motion exercises from the beginning of week 3 through week 8.
2. Immobilization (IM): The patient was instructed to wear the orthosis at all times and was not allowed to move the ankle before week 9. Rehabilitation from weeks 9 to 16 was organized as group exercises twice a week at the hospital and was identical for the 2 groups.
Participants performed ECM of the ankle joint while sitting on the edge of a table with both legs hanging. After allowing the foot to be pulled downward by gravity, the patient actively flexed the foot upward to a horizontal position. This was performed at least 5 times a day in series of 25 repetitions. The treatment protocols for the 2 groups were similar except for the intervention.
The outcome measure was DVT at 2 or 8 weeks assessed with color Doppler sonography. Secondary outcome measures were the Achilles tendon Total Rupture Score (ATRS), the heel-rise work test, elongation of the tendon measured with the Copenhagen Achilles ultrasonographic Length Measurement, perimeter of the calf, return to work, and return to sport.
Several structured scoring systems have been developed to predict the risk of DVT; the most well-studied is the Wells score which investigates the signs, symptoms, and risk factors for DVT.
Treatment of DVT:
Patients diagnosed with DVT underwent a blood test to investigate D-dimer and plasma electrolytes.
Finding suggests that in patients with acute Achilles tendon rupture, D-dimer testing cannot be used to rule out DVT, as their overall high risk of DVT reduces the negative predictive value of D-dimer. Our data suggest that Wells score and color Doppler sonography are more sensitive and accurate tools for the detection of DVT after acute Achilles tendon rupture, regardless of treatment protocol.
The study hypotheses were rejected, as the ECM protocol revealed no benefit versus immobilization in reducing the incidence of DVT. Furthermore, DVT did not seem to negatively affect outcome at 1 year after rupture. ECM of the ankle 5 times a day from weeks 3 to 8 after rupture does not seem to be the key in reducing the risk of DVT. The large difference in incidence of isolated distal DVTs and proximal DVTs raises the question of whether below-knee DVTs are of clinical relevance.
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