Case of the Week #6
Acute rupture of the Achilles tendon in a 37yo netballer managed non-operatively, complicated by DVT
Mrs B is a busy 37 year old Mum to three boys, and ruptured her right Achilles tendon playing netball. She initially presented to her physiotherapist one day after the injury, and gave a clear history of a 'snap' at the back of her ankle. She was immediately placed in a CAM boot with a heel raise and was referred to our private fracture clinic for review after a consultation and referral from her General Practitioner.
On examination, there was a clear rupture of the Achilles tendon. Squeeze test (also known as Thompson's test, see figure 2) was positive, suggesting complete rupture at the Achilles tendon. She also had a palpable divot approximately 5cm from the insertion of the Achilles tendon. An ultrasound and MRI scan ordered prior to review demonstrated a complete rupture of the Achilles tendon (see figure 1 below).
figure 1: T1 weighted MRI scan demonstrating rupture of the Achilles tendon
Of some concern, she also had a very tight calf, particularly proximally, and we were concerned about the potential for a DVT. We sent her for an urgent doppler ultrasound which demonstrated a large above knee DVT. Sara was commenced on apixaban 10mg bd immediately. She had no prior history of DVT, including during her previous pregnancies.
We discussed operative versus non-operative management for her Achilles tendon rupture. The risks of non-operative management include functional lengthening and a re-rupture risk of approximately 7% (Willets 2010, below). Her prompt diagnosis and immobilisation by her physiotherapist during her first appointment one day after injury dramatically improved the outcome of non-operative management. This is because the risk of functional lengthening was reduced as the tendon edges were mechanically opposed early in the course of her injury. Risks of surgery include infection, a re-rupture risk of approximately 3% and sural nerve injury. In this case, surgery would also require cessation of anticoagulant medication in the setting of a large above knee DVT which increased her risk of fatal pulmonary embolus. We therefore decided to proceed with non-operative management as per our standard Achilles tendon rupture protocol (see below).
Mrs B was permitted to weight bear as tolerated in a CAM boot with heel raise, and come out of the boot for showers, but to be worn for sleep. After six weeks, we reduced the wedge by 1cm each fortnight and Mrs B was weight bearing in with a plantargrade ankle twelve weeks after her injury. Clinical examination demonstrated a negative squeeze test but significant calf wasting. She was referred back to her initial physiotherapist for a strengthening and rehabilitation program. Twelve months post injury, Mrs B has returned to running and high impact activity. She has some mild residual pain in her Achilles but is able to undertake all her regular exercise activities without limitation. Her DVT resolved on ultrasound six months after her initial injury and anticoagulation was ceased. Management of an acute rupture of an Achilles tendon is a topic of much debate amongst orthopaedic surgeons. Recent evidence in the form of well-controlled randomised controlled trials (eg Willetts 2010) indicates clinical outcomes (plantarflexion strength and dorsiflexion range) are similar with non-operative management following a functional rehabilitation program compared to surgical repair.
It is important the tendon edges are opposed early in the injury, ideally within 72 hours, to avoid the risk of the tendon healing in an elongated position. Tendon edge opposition can occur either by placing the patient immediately in a plantarflexed cast, front slab or CAM boot with 3cm heel raise.
DVT is a common complication of acute Achilles tendon rupture, as well as surgery to the Achilles tendon, due to loss of the gastrocsoleal pump and venous stasis. Treating clinicians need to be aware of the high risk of DVT in this patient population and have a low threshold for referring for an urgent doppler ultrasound and commencement of appropriate anticoagulation.
Imaging is not always required to diagnose an Achilles tendon rupture. Clinical examination via careful inspection for a palpable divot, combined with a positive squeeze test (see figure 2 below) is often enough to diagnose a rupture of the Achilles tendon. Ultrasound is useful if the diagnosis is equivocal, for example in a suspected partial rupture. MRI is usually utilised for chronic rupture or concern for alternative diagnosis.
figure 2: NEGATIVE squeeze test (ankle moves into plantarflexion when squeezing the calf, suggesting the Achilles tendon is intact).
Key learning points:
Non-operative management of an acute rupture of the Achilles tendon can result in good functional outcomes and are comparable to surgical intervention.
Early immobilisation within 72 hours of injury in either a plantarflexed cast or CAM boot with heel wedge improves the outcomes of non-operative management.
DVT is a common complication of injury and surgery to the Achilles tendon.
An ultrasound is a useful imaging modality to confirm an Achilles tendon rupture, but is not required if the clinician is confident in their diagnosis.