Appearance of the weight-bearing lateral radiograph in retrocalcaneal bursitis.
OBJECTIVE
A retrocalcaneal bursitis is caused by repetitive impingement of the bursa between the Achilles tendon and the posterosuperior calcaneus. The bursa is situated in the posteroinferior corner of Kager's triangle (retrocalcaneal recess), which is a radiolucency with sharp borders on the lateral radiograph of the ankle. If there is inflammation, the fluid-filled bursa is less radiolucent, making it difficult to delineate the retrocalcaneal recess. We assessed whether the radiographic appearance of the retrocalcaneal recess on plain digital (filmless) radiographs could be used in the diagnosis of a retrocalcaneal bursitis.


METHODS
Whether or not there was obliteration of the retrocalcaneal recess (yes/no) on 74 digital weight-bearing lateral radiographs of the ankle was independently assessed by 2 observers. The radiographs were from 24 patients (25 heels) with retrocalcaneal bursitis (confirmed on endoscopic calcaneoplasty); the control group consisted of 50 patients (59 heels).


RESULTS
The sensitivity of the test was 83% for observer 1 and 79% for observer 2. Specificity was 100% and 98%, respectively. The kappa value of the interobserver reliability test was 0.86. For observer 1, intraobserver reliability was 0.96 and for observer 2 it was 0.92.


CONCLUSIONS
On digital weight-bearing lateral radiographs of a retrocalcaneal bursitis, the retrocalcaneal recess has a typical appearance.
van Sterkenburg
Maayke N
MN
Department of Orthopaedic Surgery,Academic Medical Center, University of Amsterdam, the Netherlands. m.n.vansterkenburg@amc.uva.nl
Muller
Bart
B
Maas
Mario
M
Sierevelt
Inger N
IN
van Dijk
C Niek
CN
D000293:Adolescent; D000328:Adult; D000368:Aged; D002062:Bursitis / Q000000981:diagnostic imaging*; D002111:Calcaneus / Q000000981:diagnostic imaging*; D006801:Humans; D008875:Middle Aged; D015588:Observer Variation; D011859:Radiography; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016474:Weight-Bearing; D055815:Young Adult
HSS J. 2006 Feb;2(1):27-9
18751843
Radiologe. 1974 Oct;14(10):457-67
4548199
Orthop Clin North Am. 1994 Jan;25(1):41-6
8290230
Radiologe. 1974 Oct;14(10):454-6
4438635
JAMA. 1992 May 20;267(19):2638-44
1573753
Pediatr Radiol. 1985;15(2):119-22
3975103
J Anat. 2006 Jan;208(1):91-7
16420382
Skeletal Radiol. 1979 Apr 10;4(1):21-5
515746
J Foot Ankle Surg. 2009 Jul-Aug;48(4):447-51
19577720
Radiology. 1982 Jul;144(1):83-8
7089270
Clin Orthop Relat Res. 1984 Jul-Aug;(187):228-34
6744723