Valvular Mechanisms in Antecubital Cysts of Rheumatoid Arthritis

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1 BRIEF COMM U N CATION Valvular Mechanisms in Antecubital Cysts of Rheumatoid Arthritis George E. Ehrlich and Gad G. Guttmann Two further cases of antecubital cysts resulting from rheumatoid arthritis are reported, both having valvular mechanisms permitting synovial fluid to pass from the elbow joint to the cyst but not the reverse. Rice bodies and synovial villous proliferation act as ball-valves and the long neck of some cysts may act as Bunsen valves. One synovial cyst was successfully excised, while another underwent spontaneous regression after successful surgery at the wrist restored more nearly normal prontation and spination of the forearm. Development of juxtaarticular cysts in the forearm ad.jacent to the elbow, morphologically similar to popliteal cysts, was recently described (1). The report of 2 cases emphasized that the cysts fill with dye during arthrography of the elbow, but that retrograde filling of the elbow joint could not be accomplished when dye was injected directly into the cyst. Two further cases are reported that shed further light on the possible causes of antecubital cysts and their valvular mechanisms. CASE REPORTS Case 1 HR, a 47-year-old executive, gave a 7-year history of rheumatoid arthritis. No apparent elbow arthritis or flexion contractures of the elbows were discovered at consultation in In September 197 1, pain, swelling and instability of the right knee led to admission. Examination now dis- From the Arthritis Center, Albert Einstein Medical Center-Moss Rehabilitation Hospital, Philadelphia, Pa. GEORGE E. EHRLICH, MD: Director of The Arthritis Center and Professor of Medicine and Associate Professor of Rehabilitation Medicine, Temple University School of Medicine, Philadelphia, Pa; GAD c. GUTTMANN, MD: Attending in Orthopedic Surgery, Albert Einstein Medical Center-Moss Rehabilitation Hospital, Philadelphia, Pa. Reprint requests should be addressed to: Dr. George E. Ehrlich, York and Tabor Roads, Philadelphia, Pa Submitted for publication April 19, 1972; accepted Oct 16, closed marked progression of bilateral distal radioulnar joint disruption and a 15" flexion contractwe of the left elbow, accompanied by a nontender rounded swelling in the antecubital fossa (Figure 1 ). This swelling had developed during the preceding 4 months, without history of local trauma. While there was no obvious swelling or crepitus of the elbow joint, the mass had a springy consistency suggestive of fluid-filled antecubital cyst. The laboratory data included hemoglobin 12.9g%, with the rest of the hemogram being unremarkable. Erythrocyte sedimentation rate measured 91 mm/hr (Westergren). Serum uric acid was 6.3 mg%, albumin 3.4 g% and globulin 3.6 g%. On protein electrophoresis, u2- were increased. Latex fixation for rheumatoid factor was positive in a titer of 1 :320. Lupus erythematosus cell preparations were negative. Antinuclear antibodies were not found. Roentgenograms of the left elbow were unremarkable, revealing no evidence of juxtaarticular osteoporosis, joint narrowing or destructive changes (Figure 2). An arthrogram of the left elbow, employing Renografinm, outlined an apparently normal joint, hut the dye also filled a huge cyst extending anteriorly into the antecubital fossa and down the proximal one-third of the forearm (Figure 3). Filling defects within this cyst suggested considerable villous hypertrophy and proliferation. The dye was removed from the cyst by direct aspiration, and an additional 30 milliliters of Renografin was introduced into the cyst directly (Figure 4). Massage of the cyst and compression with elastir bandages failed to introduce dye retrograde into the elbow joint. An anhrogram of the right knee performed at the same time revealed rheumatoid changes and a small popliteal cyst. Synovial fluid removed from the left antecubital cyst at the time of arthrography was amber and opalescent, with low viscosity, and formed a poor mucin clot upon addition of 5% acetic acid. It contained 11,800 white blood cells, Arthritis and Rheumatism, Vol. 16, No. 2 (March-April 1973) 259

2 Fig 1. Antecubital cyst of 4 weeks duration (Case 1). Fig 2. Roentgenogram of left elbow is relatively unremarkable (Case 1). 260 Arthritis and Rheumatism, Vol. 16, No. 2 (March-April 1973)

3 VALVULAR MECHANISMS Fig 3. Arthrogram of the left elbow. Renografin also fills the large antecubital cyst. Proliferative synovitis is implied by the filling defects (Case 1). 6,100 red blood cells, no crystals and the undigested fluid yielded a titer of 1 :640 when tested by latex fixation for rheumatoid factor. Smears and cultures were negative. Despite instillation of methylprednisolone acetate at arthrography, the effusion of the right knee recurred within 4 days and the effusion of the antecubital cyst recurred after 2 weeks. At surgery 6 days after arthrography, a popliteal cyst was removed as part of synovertomy and interposition arthroplasty of the right knee. Twelve days later the patient experienced paresthesias of ulnar nerve distribution in the left hand. Nerve conduction velocities measured 38.7 meters/sec; from below the elbow to the wrist, 54.3 meters/sec. These readings confirmed slowed ulnar nerve conduction across the elbow. Six days later a large antecubital cyst was removed from the left forearm by an anterior approach. It was seen to lie along the bicipital tendons, extending to the proximal radioulnar joint at the level of the brachial tuberosity, and measured 7.5 x 1 1 cm. It contained a large amount of synovial fluid, numerous free rice bodies and villonodular hypertrophic synovi- um. The neck of the cyst was narrow and curved and was blocked by hypertrophic synovial villi, which prevented retrograde escape of fluid even after the cyst was removed in toto. Similar hypertrophic synovium was removed from the elbow joint itself and from the proximal radioulnar joint. On microscopy, the synovial surface displayed exuberant villous proliferation with moderately intense lymphocytic and plasmocytic infiltration. A few areas of surface eosinophilic deposits suggestedfibrznozd material, and small focal calcitic areas were also present. Recovery from both operations was uneventful, and to date, 1 year later, the antecubital cyst has not recurred. UInar nerve paresthesias disappeared postoperatively and nerve condurtion velocity returned to normal across the elbow. Case 2 ME, a 64-year-old housewife, gave a 10-year history of rheumatoid arthritis and complained of pain and limitation Arthritis and Rheumatism, Vol. 16, No. 2 (March-April 1973) 261

4 EHRLICH 81 GUTTMANN olecranon bursa. An antecuhital cyst, measuring 5 crn in diameter, was palpable and bulged just below the flexion crease at the right elbow. Hemogram was unremarkable. Erythrocyte sedimentation rate was 55 mm/hr (Westergren). Antinuclear antibodies and thyroid antibodies were not demonstrable, LE preparations were negative and latex fixation test for rheumatoid factor was positive in a titer of I:l60. Serum uric acid was 6.5 mg%, serum alhurnin 3.7 g% and serum glohulin 3.0 g%. Serum protein electrophoresis disclosed a slight increase in az- and y-globulin fractions, hut immunoelectrophoresis was normal. Anti-DNA binding was 7%. Arthrography of the right elbow disclosed cystic outpouchings of the elbow joint into the antecuhital area and posteriorly along the olecranon process (Figure 5). The antecuhital cyst had filling defects suggestive of villous proliferation. Retrograde filling of the elbow,joint could not he accomplished by direct in.jection of Renografin into the antecuhital cyst, despite massage and compression dressings over the cyst. Synovectomy of the right wrist and intercarpal,joints was associated with amputation of the tip of the ulna. Surgical correction of the antecuhital cyst was planned, hut despite the fact that corticosteroid had not ever been instilled, the antecuhital cyst diminished within days after surgical Torrection of the wrist. It has failed to become palpable or visible again during a 6-month follow-up period. Fig 4. Injection of renografin into the cyst fails to fill the elbow joint despite massage and cornpression of the cyst. However. a slight amount of dye, residual of earlier arthrography. is still visible in the joint (Case 1). of motion of the right wrist and right elbow. Both elbows were contracted in 25" of flexion. There was marked synovial swelling on the extensor aspects of both wrists, accompanying disruption or both distal radioulnar joints and extensor carpi ulnaris tenosynovitis. A small rheumatoid nodule was palpated in the wall of the right DISCUSSION Anterubital cysts are in many respects comparable to popliteal cysts. The mechanism of formation of the latter. long a subject of controversy, has been the subject of 21 series of scholarly papers by Jayson and Dixon (2-4). They have suggested that an increase of intraarticular pressure produced by physical activity can lead to rupture of the knee joint or blouwut herniation of the synovium, resulting in synovial cysts (3). They have been impressed that in most cases synovial fluid can move from the joint into the cyst but can rarely reverse its course. Valvular mechanisms are hypothesized, although the type of valvular connection remains speculative (4). A ball-valve, with a narrow channel through which fluid can be pumped from the knee into the cyst, could be the result of large quantities of fibrin within the cyst plugging the opening, preventing retrograde flow. The alternative Bunsen explanation suggests a narrow curved passage whose walls 262 Arthritis and Rheumatism, Vol. 16, No. 2 (March-April 1973)

5 VALVULAR MECHANISMS Fig 5. Broad-necked cyst adjacent to elbow in antecubital fossa; multiple sites of blow-out of the elbow joint are suggested (Case 2). collapse under direct cyst pressure. That increased intraarticular pressure is indeed responsible was later suggested by these same authors in a study of 7 patients whose popliteal cysts were relieved by synovectomy of the knee joint itself (5). These operative results strongly imply that the juxtaarticular cyst serves as an escape route forjoint effusions, a mechanism no longer necessary when the synovitis producing the effusion is relieved. Further confirmation was offered by the observation that patients developing popliteal and calf cysts tended to have less dramatic swelling of the knee joint than patients not developing these lesions (3). Weight bearing extension produced the highest pressures in the rheumatoid knee (3). As pushing up to achieve the standing position is easier for most patients who have rheumatoid arthritis than pulling up, the elbow also transiently becomes a weight-bearing joint. There may, thus, also be intermittent pressure increase, abetted by attempted extension of the elbow. Every antecubital cyst we have encountered has been found adjacent to an elbow with some degree of flexion contracture. In all cases, caput ulnae syndrome (6) was also present at the ipsilateral wrist. However, while some elbows, such as those in the previous paper (l), have been the seat of considerable joint destruction, others, such as the first case reported here, have developed relatively few local changes of rheumatoid arthritis. Surgical correction of the first cyst disclosed Arthritis and Rheumatism, Vol. 16, No. 2 (March-April 1973) 263

6 EHRLICH 81 GUTTMANN both valvular mechanisms suggested by Jayson and Dixon for popliteal cysts (4). A narrow, curved and collapsible neck provided communication between.joint and cyst, producing a Bunsen-type of valve. In addition, large synovial villi were seen blocking the neck of the cyst, preventing retrograde passage of fluid from the cyst and constituting a ball-valve mechanism. Ulnar paresthesias, confirmed by a slowing of nerve conduction at the elbow, provided reminders that the ulnar nerve appears vulnerable to entrapment (1, 2-5, 7, 8). Complete remission of symptoms of entrapment followed hard upon successful surgical resection of the cyst and synovectomy of the adjacent joint. In the second patient the antecubital cyst spontaneously regressed after successful surgery to the wrist which had resulted in increased ease of pronation and supination. Altered dynamics at the proximal radioulnar joint and the elbow apparently ameliorated local factors that promoted the blow-out of these joints (7). Since we became aware of antecubital cysts, we have recognized them with increasing frequency. We believe they should be sought for, especially when patients who have rheumatoid arthritis complain of symptoms suggesting ulnar nerve entrapment. SUMMARY Two further cases of antecubital cysts resulting from rheumatoid arthritis are reported, both having valvular mechanisms permitting synovial fluid to pass from the elbow joint into the cyst but not the reverse. Rice bodies and synovial villous proliferation act as ball-valves and the long neck of some cysts may act as Bunsen valves. One synovial cyst was successfully excised, while another underwent spontaneous regression after successful surgery at the wrist restored more nearly normal pronation and supination of the forearm. REFERENCES 1. Ehrlich GE: Antecubital cysts in rheumatoid arthritis-a corollary to popliteal (Baker s) cysts. J Bone Joint Surg (Am) 54:!65-169, Jayson MIV, Dixon AStJ: Intra-articular pressure in rheumatoid arthritis of the knee. I. Pressure changes during passive joint distension. Ann Rheum Dis 29:26!-265, Jayson MIV, Dixon AStJ: Intra-articular pressure in rheumatoid arthritis of the knee. Ill. Pressure changes during joint use. Ann Rheum Dis 29: , Jayson MIV, Dixon AStJ: Valvular mechanisms in juxtaarticular cysts. Ann Rheum Dis 29:4!5-420, Jayson MIV, Dixon AStJ, Kates A, et al: Popliteal and calf cysts in rheumatoid arthritis. Treatment by anterior synovectomy. Ann RheumDis31:9-15,! Backdahl M: The caput ulnae syndrome in rheumatoid arthritis. Acta Rheumatol Srand Suppl Good JD: Synovial rupture of the elbow joint. Ann Rheum Dis 27: , Palmer DG: synovial cysts of rheumatoid disease. Ann Intern Med 70:61-68, Arthritis and Rheumatism, Vol. 16, No. 2 (March-April 1973)