Journal of Postgraduate Medicine Medknow Publications and Staff Society of Seth GS Medical College and KEM Hospital, Mumbai, India ISSN: 0022-3859 EISSN: 0972-2823 Vol. 52, Num. 1, 2006, pp. 47-48

Journal of Postgraduate Medicine, Vol. 52, No. 1, January-March, 2006, pp. 47-48

Images In Radiology

Achilles tendon enthesopathy in ochronosis

Jebaraj Isaac, Rao A*

Departments of Orthopaedics and *Radiodiagnosis, Christian Medical College, Vellore-632 004, India

Correspondence Address: Isaac Jebaraj, E-mail: ijebaraj@hotmail.com

Code Number: jp06017

A 60-year-old man presented with pain in the back of right ankle of 1 year duration. The pain was associated with walking and relieved by rest. He also complained of backache of long duration. On clinical examination his gait was awkward with short stance phase. There was thickening of the tendoachilles with nodularity. There was a palpable gap felt along the course of the tendon 2 cm proximal to the bony insertion, indicating rupture [Figure - 1]. He also had smooth kyphosis and reduced movements of the lumbosacral spine. On further examination he had thickening of the pinna bilaterally.

A clinical diagnosis of spondyloarthropathy was made and he was subsequently investigated.

His hemogram was within normal limits. Lateral radiograph of the ankle showed small focus of calcification in the region of Achilles tendon with increased thickness [Figure - 2]A. Radiograph of lumbosacral spine revealed intervertebral discal calcification, which was suggestive of ochronosis [Figure - 2]B. This was further confirmed by urine high-performance liquid chromatography (HPLC) for homogentisic acid. High-resolution ultrasound (US) examination of tendoachilles showed loss of fibrillary pattern in the tendon, increased thickness, small focus of calcification, increase in size of retrocalcaneal bursa, and complete rupture of the tendon [Figure - 3]. There were also foci of chuncky calcifications at the site of tendinous insertion with posterior acoustic shadowing [Figure - 4]. The calcification that was seen on US at the site of tendinous rupture was not seen on plain radiograph.

Discussion

Spondyloarthropathy is a common clinical condition, which has multiple etiological factors such as ankylosing spondylitis, Reiter's disease, psoriasis, and inflammatory bowel disease. Ochronotic spondyloarthropathy is associated with kyphotic deformity of the spine with polyarthritis. Ochronosis is an autosomal recessive disease with a prevalence of about 1 : 1,000,000.[1] Plain radiograph of lumboscral spine reveals intervertebral discal calcification in almost all the patients with ochronosis after middle age, as was seen in our case.

Spontaneous tendon ruptures are quite a common occurrence in these patients. Frequently they present with tendoachilles rupture as a first clinical manifestation. Findings noted at clinical evaluation alone are often suggestive of the diagnosis of acute rupture of the Achilles tendon. However, because the flexor, peroneal, and plantaris tendons also contribute to plantar flexion and can compensate, to some degree, for an injured Achilles tendon, the clinical examination can be inconclusive. Similarly, edema caused by an acute tear can obliterate a tendon defect, which renders palpation ineffective. Researchers[2],[3] have reported that more than 20% of full-thickness tears can be missed clinically at initial presentation. When the clinical examination is equivocal or there is a delay in presentation, further evaluation with imaging, such as ultrasonography, aids the diagnosis. The differentiation of full-thickness tears from less severe pathologic findings is of major importance.[3] Full-thickness tears are treated with surgical repair or, in some cases, with casting with the ankle in the talipes equinus position. A partial-thickness tear or tendinosis is usually successfully treated by using conservative measures, with surgery undertaken only after a failure of conservative therapy.[4]

Plain radiography has a limited role in diagnosing early tendonitis, in which an US detects early calcification and increased thickness of the tendon as in our case. Magnetic resonance imaging (MRI) is the other imaging modality for the evaluation of tendoachilles enthesopathy, which has the advantage of detecting the insertional bone edema associated with enthesopathy.[5] US examination is equal to or more sensitive than MRI in diagnosing early enthesopathy.[6] An US study has also the advantage of detecting early calcification associated with tendon ruptures as well as the advantages of availability, low cost, and reliability, though it requires considerable expertise in diagnosing tendon ruptures.

In conclusion, when middle-aged patients present with chronic backache and enthesopathy, one should keep in mind the possibility of ochronosis, which can be confirmed by urine chromatography for homogentisic acid. Evaluation of the extent of tendon rupture in these patients can be made with the help of ultrasonography, which is cost-effective.

References

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