Andrea Donovan MD, Presenter: Nothing to Disclose

Zehava Sadka Rosenberg MD, Abstract Co-Author: Nothing to Disclose

Posterior tibial tendon (PTT) dysfunction with secondary hindfoot valgus can lead to abnormal bony contact between the lateral talus/calcaneus (extra-articular impingement) and fibula/calcaneus (subfibular impingement), necessitating bony surgical intervention. The purpose of this study was to correlate MRI evidence of lateral hindfoot bony impingement in patients with PTT tears with a) severity of hindfoot valgus and b) grading of tendon tear.

MR images from 75 patients (45 female, 30 male; mean age 58 years, range 29-90 years) with clinical (n=45) and/or MRI (n=75) evidence of PTT tears were assessed by 2 musculoskeletal radiologists for: 1) Grading of PTT tear, 2) Hindfoot valgus angle, 3) Lateral hindfoot bony impingement defined as bony contact or opposing marrow signal change at a) extra-articular lateral talus/calcaneus and/or b) fibula/lateral calcaneus, 4) Peroneal tendon dislocation and 5) Lateral malleolar bursa. Clinical records were reviewed in all. Cochran-Armitage test, Fisher’s exact test and exact Mann-Whitney test were used to analyze the findings.

28 cases of lateral hindfoot bony impingement were identified: 6 talocalcaneal, 8 subfibular, and 14 talocalcaneal/subfibular. The prevalence of impingement significantly increased with PTT tear severity (p=0.018), and with greater hindfoot valgus angle (p<0.001). Peroneal tendon subluxation was present only in moderate or severe hindfoot valgus (p=0.0097) and only in cases of talocalcaneal/subfibular impingement (p=0.0048). There was no significant association between lateral malleolar bursa and hindfoot valgus severity or bony impingement (p>0.05).

Lateral hindfoot bony impingement was more commonly seen with advanced PTT tear and with greater hindfoot valgus angle. Thus, grading of PTT tear and measurement of hindfoot valgus angles on MRI may aid in detection of early bony impingement.  

Lateral hindfoot bony impingement, possibly necessitating surgical intervention, should be considered in cases of advanced PTT tears and increased hindfoot valgus angle.

Donovan, A, Rosenberg, Z, MRI of Lateral Hindfoot Bony Impingement in Patients with Posterior Tibial Tendon Tear and Hindfoot Valgus.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6018308.html