Extensor Tendon Rupture Over the Metacarpal Heads in Rheumatoid Arthritis M. L. Clayton, R. Thirupathi, D. C. Ferlic. and B. Goldberg E X T E N S O R T E N D O N R U P T U R E OVER THE M E T A C A R P A L H E A D S
M. L. Clayton, R. Thirupathi, D. C. Ferlic, and B. Goldberg, Denver, Colorado SUMMARY Rupture o f the extensor tendons is common in longstanding rheumatoid arthritis o f the hand. The tendons c o m m o n l y involved are those o f the ring and little fingers and the c o m m o n site o f rupture is over the dorsal ulna and distal edge o f the extensor retinaculum. We are reporting two cases o f extensor tendon rupture over the metacarpal head o f the middle finger due to prominent osteophytes.
Case 1. A thirty-three year old female, juvenile rheumatoid arthritic from the age of one and one-half years, lost the ability to extend the right middle finger actively. The extensor tendon was visible both proximal and distal to the metacarpophalangeal joint. She had marked synovitis of this joint of both the index and middle fingers. Passively, the fingers could be brought up to within 20 ~ of full extension without pain. An x-ray of the hand revealed Stage iii rheumatoid arthritis. At the time of surgery, the extensor tendon was found to be ruptured over a bony spur of 5mm x 5mm size, which was located on the middle of the metacarpal head. (Fig. 1). The ends of the tendons were prevented from retracting by the stretched capsule of the joint. The metacarpal head was excised and the patient underwent end to end repair of the extensor tendon with silastic implant arthroplasty of the joint. She gained full function of the hand with normal active extension of the finger. Case 2. A sixty year old female, with severe rheumatoid arthritis and a history of frequent tendon rupture, lost active extension of the middle finger. The wrist was explored through a dorsal incision and the extensor retinaculum was reflected from its ulnar border. The extensor tendons were intact at this level and the tendon was traced further distally. A prominent osteophyte with the ruptured extensor tendon was found over the metacarpal head of the middle finger. Repair was not possible since there was no tendon distal to the rupture. The bony spur was excised from the metacarpal head.
DISCUSSION Extensor tendon rupture is a major cause of disability in the rheumatoid hand. Spontaneous tendon rupture is caused by many factors: Increased pressure in the sheath and granulomatous pannus erosion of the tenosynovium along the vincular vessels into the tendon causes a weakening of the tendon. Aseptic necrosis of the tendon occurs due to ischemia resulting from vincular vessel compression by the surrounding hypertrophic synovium. Tendon rupture may occur after local steroid injection. Direct pressure from abnormal tenosynovium and the unyielding extensor retinaculum, especially its distal margin, may cause tendon ruptur.e.
Donald C. Ferlic,M.D. DenverOrthopedicClinic, 2005Franklin Street, Denver,Colorado80205U.S.A. The Hand-- Volume 15
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1983
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Extensor Tendon Rupture Over the Metacarpal Heads in Rheumatoid Arthritis M. L. Clayton, R. Thirupathi, D. C. Ferlic, and B. Goldberg
Fig. 1. Bony spur 5mm x 5mm size (arrow) over the metacarpal head.
Abnormal rough bone surface with spurring and osteophyte formation due to the nature of the disease is the most common cause of tendon rupture. (Clayton, 1965; Clayton and Ferlic, 1975; Straub, 1956). The dorsally displaced distal ulna with its roughened margins is the most common site for rupture due to bony spurs which may rub against the extensor tendons of the middle, ring and little fingers. (Vaughan-Jackson, 1948) This gradual process results in the attrition rupture. The next most common site of attrition rupture is Lister's tubercle on the radius, round which the long thumb extensor tendon turns acutely towards the thumb. Bony spicules of scaphoid and trapezium were found to cause flexor tendon rupture by Mannerfelt (1969). Fowler (1963) reported tendon rupture due to the osteophyte from the hook of the hamate. The bony spike at the head of the metacarpal has not been reported in the literature as a site for attrition rupture of the extensor tendon in rheumatoid arthritis and these two cases clearly demonstrate that this is a possible site of tendon rupture in the rheumatoid hand. A patient who clinically presents with extensor rupture but appears to have intact tendons over the dorsum of the wrist should undergo careful examination of the involved metacarpal area also. In addition, patients who are undergoing metacarpophalangeal arthroplasty and who are unable to extend the metacarpophalangeal joints should have a careful check of the extensor tendon mechanism at the time of surgery. We have seen cases where these seem to have parted and stretched and require reefing to restore extension. REFERENCES CLAYTON, M. L. (1965). Surgical Treatment of the Wrist in Rheumatoid Arthritis, A Review of Thirty-seven Patients. The Journal of Bone and Joint Surgery, 47A: 741-750. CLAYTON, M. L., and FERLIC, D. C. (1975). The Wrist in Rheumatoid Arthritis, Clinical Orthopaedics and Related Research, 106" 192-197. FOWLER, S. B. (1963). The Hand in Rheumatoid Arthritis. The American Surgeon, 29: 403-404. MANNERFELT, L., and NORMAN, O. (1969). Attrition Ruptures of Flexor Tendons in Rheumatoid Arthritis Caused by Bony Spurs in the Carpal Tunnel, The Journal of Bone and Joint Surgery, 51B: 270-277. STRAUB, L. R. and WILSON, E. H. (1956). Spontaneous Rupture of Extensor Tendons in the Hand Associated with Rheumatoid Arthritis. The Journal of Bone and Joint Surgery, 38A: 1208-1217. VAUGHAN-JACKSON, O. J. (1948). Rupture of Extensor Tendon by Attrition at the Inferior Radioulnar Joint, Report of Two Cases. The Journal of Bone and Joint Surgery, 30B: 528-530. 150
The Hand-- Volume 15
No. 2
1983