A twenty-eight-year-old man was referred to our institution for evaluation of a mass that had been present for ten months in the right antecubital fossa. The patient reported no history of trauma and was in good general health.
On examination, a cystic mass, measuring approximately three by five centimeters, was identified in the antecubital fossa. When compared with the contralateral elbow, the right elbow lacked 10 degrees of full active extension and 10 degrees of full active flexion. The forearm pronated 60 degrees and supinated 90 degrees. Motion of both the elbow and the forearm was pain-free. No locking or crepitation was noted on passive motion of the elbow. The neuromuscular examination of the hand revealed normal findings.
Standard anteroposterior and lateral radiographs demonstrated distortion of the radial head and neck (Figs. 1-A and 1-B). The radial neck was sclerotic and narrowed, resembling an apple core, and the radial head appeared enlarged, with irregularity of the proximal radio-ulnar joint. A soft-tissue swelling was seen lying anterior to the radial head and neck. Magnetic resonance imaging demonstrated that the lesion was composed of two portions: a cystic mass in the antecubital fossa and a segment encircling the narrowed radial neck. On the T1-weighted image made with enhancement with gadolinium-diethylene triamine penta-acetic acid, both components of the mass were of low signal intensity (Fig. 2), whereas, on the T2-weighted image, they were of high intensity. Arthrography of the elbow, done with injection of contrast medium through a needle inserted through the triceps tendon, demonstrated normal articular cartilage and a normal joint cavity, without evidence of intra-articular loose bodies. However, the annular periradial recess that encircles the radial neck failed to show complete filling with the contrast medium. A second injection of contrast medium was made directly into the mass in the antecubital fossa, and the lesion appeared to be cystic and multilocular, extending toward the bicipital tuberosity without direct communication with the joint (Fig. 3).
The results of hematological investigations were normal, including an erythrocyte sedimentation rate of four millimeters per hour and a level of C-reactive protein of zero milligrams per deciliter (normal, zero to 0.3 milligram per deciliter).
Aspiration of the cystic mass in the antecubital fossa yielded yellowish, viscous, transparent fluid. Additional diagnostic tests of the fluid were not performed.
Preoperatively, the clinical diagnosis was a periosteal ganglion arising from the annular ligament and extending into the antecubital fossa. It was made in view of the similarity between the intensities, on magnetic resonance images, of the cystic lesion in the antecubital fossa and the mass around the radial neck.
At the operation, the antecubital fossa was explored through a curvilinear incision. A cystic mass was found adherent to the biceps tendon on the radial side. The mass was exposed by sharp and blunt dissection along the tendon to its deep portion, but there was no visible origin. The mass was resected at its base to improve visibility of the operative field. Then, the supinator was incised just proximal to the base of the mass to explore the segment of the lesion around the radial neck. The annular periradial recess that encircles the radial neck was found to be crowded with multiple cartilaginous nodules surrounding the radial neck and head (Fig. 4). The nodules were removed, and the annular ligament appeared normal.
The operative specimens were sectioned and stained with hematoxylin and eosin. Histological examination showed that the nodules were composed of lobular hyaline cartilage. A synovial membrane and loose connective tissue were identified on the surface of the nodules. Clustering of cartilage cells without atypia was visible, and no zone of calcified or ossified matrix was found among the clusters. Histological examination of the cystic lesion from the antecubital fossa revealed that the cyst was composed of a collagenous membrane and synovial lining, with minimum infiltration of inflammatory cells. The diagnosis of cubital bursitis in association with synovial chondromatosis was made on the basis of both the operative and the histological findings.
Postoperatively, the elbow was supported in a sling for two weeks and then was mobilized progressively. The evaluation at ten months postoperatively showed no recurrence of the cystic mass in the antecubital fossa, improvement of pronation to 75 degrees, and no change in the preoperative flexion and extension of the elbow.
The biceps tendon inserts into the rough posterior area of the bicipital tuberosity, and a bursa separates the tendon and the smooth anterior area of the tuberosity3. This bursa has been anatomically termed the bicipital radial bursa and has been recognized for more than 200 years5. Its enlargement presenting as cubital bursitis is an extremely unusual condition. In their report of two patients, Karanjia and Stiles speculated that the etiology of the bursitis was repetitive mechanical trauma. In addition, el-Hadidi and Burke documented the case of a patient with this type of bursitis who was seen initially with a posterior interosseus nerve syndrome.
The more common symptoms associated with articular chondromatosis include pain, swelling, loss of motion, and locking, and the most common physical signs consist of soft-tissue swelling, crepitation, palpable loose bodies, and limitation of motion6. In our patient, the sole presenting symptoms and signs were related only to the development of a soft-tissue swelling in the antecubital fossa.
The diagnosis of intra-articular synovial chondromatosis can be difficult on standard radiographs when there are no calcifications in the cartilaginous nodules. Imaging techniques, such as arthrography or computed arthrotomography, have been shown to be useful in the diagnosis of synovial chondromatosis7. Some authors have suggested that magnetic resonance imaging provides greater accuracy than computed tomography in the diagnosis of these lesions9. It is noteworthy that we were unable to reach the correct diagnosis preoperatively despite the use of these sophisticated imaging techniques.
In the elbow joint, the synovial membrane descends distal to the distal border of the annular ligament3. This synovial cavity, termed the annular periradial recess, which encircles the radial neck, normally communicates with the main articular cavity of the elbow through an isthmus made by the annular ligament3,5. Osseous changes due to increased intra-articular pressure have been reported in the hip2,7. In our patient, the annular periradial recess itself appeared to be a limiting factor, as the articular chondromatosis may have mechanically blocked the normal communication of synovial fluid from the recess to the main articular cavity. This may be the reason why the osseous changes developed in the radial head and neck while the cubital bursa became secondarily distended by the influx of the synovial fluid produced in the annular periradial recess.
NOTE: The authors thank Yoshitaka Tani, M.D., Yasuro Asano, M.D., and Hidetoshi Okabe, M.D., for their contributions to this study, and Ms. Yuriko Katagami and Ms. Kimberly Kushida for their help in preparing this manuscript.