Article
Extensor tendon rupture in non-traumatic osteoarthritis of distal radioulnar joint – A rare case report
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Authors
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Neeraj Godara
- Ganga Hospital & Medical Center, Coimbatore, India
| Published: | February 6, 2020 |
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Outline
Text
Osteoarthritis of DRUJ with rupture of extensor tendon is a rare problem seen in elderly, though it is commonly found in patients with rheumatoid arthritis. A rupture of dorsal capsule of DRUJ causes a dorsal dislocation of ulnar head. Tendon transfer with excision of ulnar head is a viable option. One should look out for 'scallop sign'1 in order to do surgery before the rupture of extensor tendon is possible. We present a case of extensor tendon rupture of 4th and 5th fingers in a patient with non-traumatic osteoarthritis of distal radioulnar joint.
Methods: A 60 year old right hand dominant woman presented in our OPD with complaints of inability to extend her right little and ring finger for three months. Initially little finger was involved and a month later the ring finger also got involved. There was no history of any trauma or any associated pain prior to it. Patient worked in a button making factory for thirty years.
Thorough examination revealed a swelling over the dorsal aspect of wrist on the ulnar side. Patient was unable to actively extend her right little and ring fingers at the metacarpophalangeal joint (Figure 1). DRUJ was found to be unstable as per load and shift test. Blood cell count, erythrocyte sedimentation rate, and C-reactive protein were within normal parameters. Rheumatoid factor as well as Anti-CCP were negative. A study of the plain radiographs revealed osteoarthritic changes at the DRUJ. Deepening and widening of the sigmoid notch and radial shift and dislocation of the ulnar head with positive ulnar variance was suspected
Results and Conclusions: In our case, we observed a definite scallop sign, a radial shift of the ulnar head, and a roughened ulnar head and positive ulnar variance. Our operative findings showed that the cause of the dorsal capsular perforation and extensor tendon rupture was mechanical friction with the dislocated roughened ulnar head.
As far as treatment is concerned end-to-end repair of tendon is not possible because of the frayed margin and the gap between the ends. Tendon graft is also not a viable option as the patients are mostly elderly. Tendon transfer is only available option in these cases with good results as reported elsewhere and in our case also. In addition the dislocated ulnar head also needs to be excised to prevent the recurrence of and further rupture.
