Bowen L, Evans R, Bodger O, Howard J, Anne-Marie H (2019) Investigating the Validity of Soft Tissue Signs on Lateral Ankle X-Ray to Aid Diagnosis of Achilles Tendon Rupture in the Emergency Department. Int J Foot Ankle 3:033.


© 2019 Bowen L, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

REVIEW ARTICLE | OPEN ACCESS DOI: 10.23937/2643-3885/1710033

Investigating the Validity of Soft Tissue Signs on Lateral Ankle X-Ray to Aid Diagnosis of Achilles Tendon Rupture in the Emergency Department

Lowri Bowen1*, Rhodri Evans2, Owen Bodger3, Joshua Howard4 and Anne-Marie Hutchison5

1Gloucestershire Academy, Redwood Education Centre, Gloucester Royal Hospital, United Kingdom

2Radiology Department, Hywel Dda Health Board, Swansea University, United Kingdom

3School of Medicine, Swansea University, United Kingdom

4Orthopaedic Department, Royal Gwent Hospital, United Kingdom

5Department of Orthopaedic, Swansea Bay University Health Board, United Kingdom



To investigate the diagnostic validity of four radiological soft tissue signs Kager's sign (K), disruption to the tendon (D), loss of parallelism (P) and fusiform swelling of the tendon (F) on a lateral ankle x-ray to aid Achilles tendon rupture diagnosis.


We retrospectively identified two groups of patients; Group A consisted of patients with an Achilles tendon rupture and Group B included patients with a clinically intact Achilles tendon but with a lateral ankle ligament sprain. Three clinicians independently reviewed all patients' x-rays for each of the radiological features under investigation to determine whether a rupture was present or not. Inter-rater and Intra-rater reliability were calculated using the Kappa coefficient (Kc.) To determine the predicted value of the signs sensitivity, specificity, positive predicted values and negative predicted values were calculated.


85 patients x-rays were included in this study; Group A n = 47, Group B n = 38. The most valid radiological sign appeared to be loss of parallelism (sensitivity 70%, specificity 97%, kappa 0.55-0.58).


Clinicians reviewing a lateral ankle x-ray of a patient with an acute ankle injury should review the x-ray for loss of parallelism between the tendon and skin; identification of this radiological sign may alert the clinician to the possible diagnosis of a ruptured Achilles tendon. Reviewing this may reduce the number of missed Achilles ruptures.