Skeletal Radiol (1996) 25:471–475 © International Skeletal Society 1996

&Guido roles: Liessi Stefano Cesari Bernardino Spaliviero Claudia Dell’Antonio Paolo Avventi

G. Liessi, M.D. (✉) · S. Cesari, M.D. B. Spaliviero, M.D. C. Dell’Antonio, M.D. · P. Avventi, M.D. Servizio di radiologia, Ospedale, I-31033 Castelfranco V.to, Ulss 8 (TV), Italy&kl / f o n - b:c

A RT I C L E

The US,CT and MR findings of cubital bursitis: a report of five cases

&Abstract p.1: Objective. The purpose of the study was to evaluate the appearance of “cubital bursitis” on ultrasonography and CT and MR imaging. “Cubital bursitis” is a rare pathological condition involving a large swelling of the bicipito-radial or interosseous bursae located at the insertion of the distal biceps tendon on the radial tuberosity. Design and patients. We report on five patients with “cubital bursitis” resulting from their work or sporting activities. All patients underwent an ultrasound and MR examination. CT scans were performed on two patients before and after contrast enhancement. Results. Ultrasound studies showed a fusiform anechoic or hypoechoic le-

sion. CT images showed the lesions but there were some difficulties in determining the exact extent of the bursae. MR imaging showed the enlarged bursae and their fluid content. Four patients each underwent a surgical procedure. Conclusion. Ultrasound and CT were effective in the evaluation of “cubital bursitis”, but with some diagnostic difficulties. MR imaging is probably the method of choice for determining both the development of the bursae and their fluid content. &Key k w d : words Elbow, magnetic resonance · Elbow, ultrasound · Elbow computed tomography · Bursitis&y b :d

Introduction

Materials and methods

Ultrasonography CT, and MR imaging have each contributed to the non-invasive evaluation of the anatomy of the elbow and lesions affecting it [1–7]. However, “cubital bursitis” is a pathological condition rarely reported in the orthopaedic literature and hence almost unknown in MR and ultrasound imaging [8, 9]. Swelling of the interosseous or bicipito-radial bursae in the cubital fossa can be related to chemical, traumatic, mechanical or infectious causes and can produce a mass with or without compression of the median or posterior interosseous nerves [8, 9]. The purpose of this study was to evaluate the ultrasound, CT and MR imaging of this condition in five patients.

Between October 1988 and November 1994 we studied five patients (four men and one woman) aged from 17 to 64 years with a tender bulging fusiform lesion of the cubital fossa. All patients were referred because of pain and impairment of flexion and extension movements; two also had impaired extension of the thumb and fingers. Bursitis was located in four patients on the right and in one patient on the left. Of the male patients two were tennis players and two were farmers; the girl (aged 17 years) was a volleyball player. On plain radiographs no abnormalities of the soft tissue of the elbow and no calcifications near the radial tuberosity were detected. All patients underwent an ultrasound examination with commercially available equipment using a 7.5 MHz linear array probe. Axial and sagittal images were also obtained during movement of the elbow using colour Doppler imaging. CT scans were performed on two patients before and after intravenous injection of contrast medium on a GE 9800 scanner with 5 mm axial contiguous sections. MR studies were carried out using a superconducting magnet (0.5 T) in four patients, one patient was studied with a resistive magnet (0.3 T). All MR examinations were performed in

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the axial and sagittal planes with SE and STIR sequences without injection of paramagnetic contrast medium; the elbows were examined using a knee coil in the supine or prone decubitus position. The imaging parameters were: TR 500/2500 ms and TE 30 and 90 ms; 256×256 matrix; FOV 220 mm; NEX 2–4; slice thickness 5–7 mm. In two patients fluid was aspirated from the lesion by an orthopaedic surgeon but no injection of contrast medium into the bursae was made. The cubital fossa was explored surgically in four patients. Each surgical procedure showed that the bicipito-radial bursa was involved. In the youngest patient, who refused surgical intervention, imaging seemed more compatible with enlargement of the interosseous bursa, considering the pressure towards the nearby median nerve. No communication of the bursae with the neighbouring joint was detected.

Results In the ultrasound studies the bicipito-radial and interosseous bursae appeared enlarged – with regular walls and anechoic fluid in three cases, while in two patients the content was hypoechoic with septa but without signs of increased vascularity during colour Doppler examinations (Figs. 1A, 2A, 3A). Fig. 1 The dilated bursa presents thick walls on ultrasonography (A) as well as on T1weighted MR images (B), with the presence of hypoechoic debris in its posterior side. The biceps tendon is clearly evident as a hyperechoic nodule on the ultrasound images (white arrow in A) and it is partially surrounded by the dilated bursa that appears double-lobed (C) and hyperintense on T2weighted images (D) with pressure towards the median as well as the interosseous nerve (black arrowheads in B)&.i c/ :gf

CT and T1-weighted axial MR images demonstrated very similar anatomical findings, because the bursa appeared as a sharp fusiform lesion without signs of surrounding vascular and muscular structures; the biceps tendon was detected characteristically at the anterior edge of the lobulated bursal wall. The walls of the bursae were thin in three cases and thick in two cases (Figs. 1B, 3B). MR imaging demonstrated the increased signal intensity of the fluid filling the bursae and the anatomical relationship with the biceps tendon (Fig. 1C, D); in two patients thin septa were detected (Fig. 2B, C). A little fluid was found in the elbow as is normal in joints (Figs. 2D, 3D). The bursae aspirated by surgeons were still enlarged some months later. Surgery was performed because in two patients the nature of the lesion was not correctly interpreted before intervention, while in two others surgical excision was necessary for decompressing the posterior interosseous nerve stretched by a bulging bicipito-radial bursa. The young woman with an enlarged interosseous bursa refused intervention because she felt her elbow had become less swollen after some weeks.

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Fig. 2 In the ultrasound study (A) the dilated bicipito-radial bursa shows the biceps tendon on its anterior side (white arrows) with some thin septa visible also on the MR axial scan, which also confirms the liquid content of the lesion (B). The interosseous bursa is dilated and surrounds the biceps tendon, thereby creating considerable pressure on the brachial artery and the median nerve (C, D)&.i c/ :gf

Histopathologic studies on the excised specimens of bursal wall confirmed a synovial bursa with signs of chronic inflammation. Post-operatively, the two patients with signs of impairment of the posterior interosseous nerve regained full neurological function.

Discussion The most common disorders involving the median and radial nerves where they cross the elbow are the pronator and supinator syndromes due to pressure by the deep head of the pronator teres and the superficial and deep portions of the supinator (arcade of Frohse) on the posterior interosseous nerve. However, mechanical compression of the nerves may also result from space-occupying masses such as ganglia and lipomas [4]. The biceps tendon inserts into the posterior edge of the biceps tuberosity of the radius and is normally separated from the tuberosity by a bursa [10, 11]. However, some anatomy texts and authors state that two bursae can be found at the anterior side of the elbow: the interosseous medial bursa in contact with the interos-

seous membrane and the bicipito-radial bursa which lies laterally [10, 11]. Enlargement of the bicipito-radial bursa may cause severe compression of the posterior interosseous nerve, while swelling of the interosseous bursa can compress the median nerve [9]. Massive enlargement or anatomical variants with intercommunication between the bicipito-radial and interosseous bursae may cause compression of both the median and radial nerve at the elbow [9]. No communication of the bursae with the elbow joint has been reported. The bicipito-radial and interosseous bursae are not seen in normal patients during ultrasound or MR studies [5]. Enlargement of these bursae in the cubital fossa can impair normal flexion and extension of the elbow and can compress the nerves mostly on pronation, which increases the tension in the bursae. Agnew [12] in 1863 was the first to describe a bursal mass causing peripheral nerve compression; in his case the bursa compressed both the posterior interosseous and median nerves. Fewer than 12 documented cases of compression of the posterior interosseous nerve due to bursitis exist, while only two cases of compression of the median nerve by an interosseous bursa have been reported recently [12–14]. In

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Fig. 3 The biceps tendon, which appears hyperechoic on ultrasonography (A) is situated on the outside front of the bursa (white arrows), which has very thin walls clearly visible on the CT scan (B) A Brachial artery, B biceps tendon. The MR axial T2-weighted image (C) shows the bursa winding (black arrowhead) around the biceps tendon. The dilated bursa contains liquid and appears wedged between the brachial, the pronator teres, and the brachioradial muscles (C, D). There is a very small quantity of liquid in the elbow joint (D) .i& c/ :gf

our experience, enlarged bicipito-radial bursae appeared, in axial images, to protrude more towards the median nerve, but the symptoms were characteristic of impairment of the deep branch of the radial nerve, probably because of the increased compression of the nerve itself during movements or because of fibrous adhesions. Even though the bicipito-radial and interosseous bursae were massively enlarged, only two patients showed signs of compression of the posterior interosseous nerve. Some reports recall the presence of ganglia near the biceps tendon, or compressing the median nerve, but without imaging or discussion of this pathology [4, 14]. Ultrasound studies can be very important in detecting typical cases and particularly for recognition of the tendon in the bursa or at its edge. The bursa can be irregular in shape due to septation or synovitis, which might cause some diagnositic difficulties. CT is a good diagnostic procedure for detecting abnormalities of the elbow on account of its high spatial resolution, but the technique of choice for studying lesions of the tendons is MR imaging. MR studies provide much better demonstration of the enlarged bursa by using the multiplanar capabilities

of the technique and also in assessing the relationship of the bursa to the biceps tendon, as well as the signal characteristics of the fluid filling the bursa. The bursitis sometimes can relapse, and resection is mandatory in patients who experience recurrence of pain after aspiration and impairment of neural function or mechanical limitations to full flexion and extension of the elbow. Swelling of these bursae could be confused with other lesions, particularly ganglia. Enlarged tendon sheaths can be excluded because the biceps tendon has no sheath at its radial insertion. In the cubital fossa some authors describe ganglia causing compression of the neighbouring nerves, but enlarged interosseous or bicipito-radial bursae differ ganglion cysts. The most interesting imaging feature for differentiating a dilated bursa from a ganglion is that the bursa is wedged between the biceps tendon and its insertion into the radial tuberosity. It must also be noted that the biceps tendon is not recognizable in the centre of the bursa, but characteristically lies on its periphery. In our experience the involved bursa was, in four cases, the bicipito-radial bursa, and the symptoms were

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related to posterior interosseous nerve impairment. However, it is very difficult, with MR imaging, always to distinguish a bicipito-radial from an interosseous bursitis, especially in patients with very enlarged bursae. Impairment of the radial and median nerves at the anterior side of the elbow can be due to other compressive causes, mostly tumours such as lipomas or haem-

angiomas which present a characteristic MR pattern [8, 16]. When an anechoic or hypoechoic mass is detected in the cubital fossa by ultrasound studies, MR imaging is the method of choice for further assessing the pathological entity, particularly when it is a swollen bicipito-radial or interosseous bursa.

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6. Mirowitz SA, London SL. Ulnar collateral ligament injury in baseball pitchers: MR imaging evaluation. Radiology 1992; 185: 573–576. 7. Ho CP. Sports and occupational injuries of the elbow: MR imaging findings. AJR 1995; 164: 1465–1471. 8. Karanija ND, Stiles PJ. Cubital bursitis. J Bone Joint Surg BR 1988; 70: 832–833. 9. Spinner RJ, Lins RE, Collins AJ, Spinner M. Posterior interosseous nerve compression due to an enlarged bicipital bursa confirmed by MRI. J Hand Surg Br 1993; 18: 753–756. 10. Treves F. Surgical applied anatomy, 12th edn. London: Cassell, 1952: 252. 11. Toldt C. An atlas of human anatomy for students and physicians. New York: Macmillan, 1928: 321. 12. Agnew DH. Bursal tumor producing loss of power of forearm. Proc Pathol Soc Philadelphia 1860–1867; 2: 139–140

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