Fatal pulmonary embolism following conservatively managed tendo achilles rupture—A case report

Abstract

Introduction

Tendo achilles (TA) ruptures are commonly encountered in orthopaedic practice. These can be managed operatively or conservatively depending on various factors like patient age, activity levels, co morbidities, patient expectations and surgeon preference. They are usually treated in plaster cast immobilisation if managed conservatively.

Case report

We present a case of fatal pulmonary embolism following conservatively managed Tendo achilles (TA) rupture in a young man treated as an orthopaedic outpatient.

Discussion

There are no current clear guidelines on venous thromboembolism (VTE) prophylaxis in conservatively managed outpatients with cast immobilisation.

Conclusion

Our case report highlights the importance of recognition of this aspect of patient management and reviews the current literature available on this debatable topic.

1. Introduction

TA ruptures are commonly encountered in clinical practice in orthopaedics. These can be managed both operatively and non operatively depending on various factors. When managed non operatively, patients are treated in plaster casts as outpatients. DVT prophylaxis in these patients is debatable and currently there no clear national guidelines in the management of such patients.

2. Presentation of case

A 34 year old healthy young adult male of British origin (height 179 cm and weight 75 kg, BMI 23.4) presented to accident and emergency with inability to weight bear while playing football. He heard a snap and felt as though somebody had shot him at the back of the ankle without any direct tackle. He was a plumber by occupation and football was his hobby. He had no risk factors like previous history of deep venous thrombosis (DVT), family history of clotting disorders, intake of medications, smoking or prior problems with his ankle. Clinical examination revealed a palpable gap in the musculotendinous junction and compression of the calf did not cause plantar flexion of the ankle suggesting complete rupture of TA.

Options available for management were discussed with him and he preferred non operative treatment. He was given above knee cast with foot in equinus for two weeks and then planned for below knee plaster with foot in equinus for two weeks followed by below knee cast with foot in neutral for two weeks at which stage plan was to let him start partial weight bearing for another four weeks.

He presented ten days following injury to fracture clinic with a sensation of the plaster feeling tight. He was examined by the orthopaedic consultant on call and his calf was soft, non tender and there was no increase in girth to suggest DVT. He felt a lot better once the plaster was removed. Decision was taken to change to a below knee cast at this stage even though it was four days earlier than planned. He was comfortable with the new below knee plaster and was given an appointment in two weeks time for the next change.

However, he represented to the fracture clinic four days later complaining of some breathlessness since the previous night. Examination revealed no clinical signs of DVT in the calf or pulmonary embolism (PE) like tachypnoea or reduced saturation on air. He was getting some chest pain on and off since few days and he felt that it was secondary to him using axillary crutches causing pectoral muscle strain. In view of his symptoms, blood tests including D dimers, Chest radiograph, clotting/antibody profile, electrocardiogram (ECG) were organised and he was admitted under the physicians.

His clotting profile, ECG and chest radiograph were normal. Blood investigations did not reveal any antinuclear/antiphospholipid antibodies. D dimers were found to be raised significantly and the calf doppler revealed a popliteal vein thrombus. He was treated empirically for PE with therapeutic dose of subcutaneous anticoagulant immediately and CT angiogram was organised for the next day. Later that night, he had cardiopulmonary arrest and resuscitation attempts failed. Post-mortem revealed a massive pulmonary embolus at the bifurcation of the pulmonary vessels.

3. Discussion

The annual incidence of venous thromboembolism (VTE) is approximately 0.1% with that of DVT being 1–2%.^{1, 2, 3} The quoted incidence of VTE following a leg injury immobilised can vary from 0.1% to 40%. Proximal vein thrombosis (symptomatic or asymptomatic) is reported to carry a risk of 50% PE.⁴ The risk of DVT has been reported as being similar for both soft tissue injuries and fractures.⁵ One case of fatal PE following ankle fracture has been reported in the English literature.⁶ Age, major operations such as lower limb arthroplasty/pelvic operations, previous history of venous thrombosis, protein C/S deficiencies, or Factor V Leiden mutation, are quoted as predisposing risk factors.⁷ VTE events generally present within the first four weeks of immobilisation³ in outpatients with injury of the lower limb although DVT has been reported within 24 h of application of the cast.⁸

Kock et al.⁸ found that the incidence of DVT was much higher (reaching statistical significance) in the no treatment group compared to prophylaxis group in their prospective randomised single centre control trial of 239 patients. Kujath et al.³ also found similar results in their RCT of 253 patients.

In the prospective randomised doubleblind placebo controlled multicentre trial by Lassen et al.⁹ of 371 patients, the incidence of DVT was higher in the placebo group which was statistically significant.

In contrast, Jorgensen et al.¹⁰ found no statistically significant difference between the treatment and control groups in the multicentre RCT of 205 patients comparing tinzaparin with no treatment. There was no placebo control in their study and it had a high dropout rate which could have affected the results.

Cochrane review¹¹ of six RCT's including the previous mentioned papers^{3, 8, 9, 10} with a total of 1490 patients comparing DVT prophylaxis with low molecular weight heparin (LMWH) with no treatment in outpatients concluded that LMWH significantly reduces VTE when immobilisation of the lower leg.

This review noted potential bias which could have affected the results in these RCT's. These studies excluded high risk patients and the drop out rate in them was on the higher side. The method of diagnosing DVT varied between ultrasonography and venography. The dosage of LMWH was different in each study and there was heterogeneity with respect to type of injury and surgical intervention.

One study¹² found low incidence of DVT and no cases of PE in conservatively treated ankle fractures and did not recommended routine VTE prophylaxis. Current American College of Chest Physicians (ACCP)¹³ and Scottish Intercollegiate Guidelines Network (SIGN)¹⁴ guidelines recommend that all patients undergoing elective hip or knee replacement should be routinely considered for LMWH prophylaxis for seven to fifteen days after operation and continued for four to five weeks in high-risk patients. This is not the same for patients with immobilisation in lower limb cast and the decision is left to the individual clinicians even though the incidence of symptomatic DVT is similar to elective lower limb arthroplasty.⁵ This is possibly due to the need for prolonged course of anticoagulation which would imply regular outpatient supervision.

Prophylaxis using warfarin has been shown to be effective in reducing the mortality from pulmonary embolism.¹⁵ Alternative options like aspirin have been found to be not as efficacious as low molecular weight heparin therapy.¹² Direct thrombin inhibitor dabigatran etexilate and the Factor Xa inhibitor rivaroxaban have been found to be as effective as LMWH in randomised trials for elective lower limb arthroplasty.⁵ Further studies are needed to prove their efficacy in DVT prevention in lower limbs immobilised with plaster.

In our department, all outpatients undergoing following lower limb immoblisation are assessed for risk of DVT and are treated with LMWH if indicated for the duration.

In a survey of current practice in the United Kingdom of thromboproplylaxis following cast immobilisation for lower limb injuries,¹⁶ there was substantial variation and inconsistency in practice among orthopaedic departments in United Kingdom due to a lack of clinical guidelines in this group and could potentially remain underused even in high-risk group patients. They recommend risk stratification to identify individuals who are likely to benefit from prophylaxis. Up to now no stratification method has proven its superiority or has gained general acceptance. We would need to form a uniform national guideline in the management of such patients.

4. Conclusion

Routine pharmacological prophylaxis to patients requiring prolonged immobilisation in a cast rather than the current practice of selective use of prophylaxis in high-risk patients is debatable. Further high quality research is needed to assess the cost-effectiveness of the increased resources needed to offer routine prophylaxis and weigh the risk-benefits to prevent long term morbidity following DVT or fatal complications like PE. The treating surgeon should have a high index of suspicion and low threshold to prevent these complications in patients treated with prolonged plaster cast immobilisation for lower limb injuries.

Conflict of interest statement

None declared.

Funding

None.

Ethical approval

Written informed consent was obtained from the next of kin for publication of this case report and accompanying images. A copy of the written consent is available for review by the Editor-in-Chief of this journal on request.

Author contributions

Santosh Venkatachalam – data collection and writing and Ken Wright – idea of the paper and editing.