| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Rheumatology 2001; 40: 420-423
© 2001 British Society for Rheumatology
Screening for extensor tendon rupture in rheumatoid arthritis
Departments of Rheumatology and Hand Surgery, Nuffield Orthopaedic Centre, Oxford OX3 7LD, UK
 |
Abstract |
|---|
 Top Abstract IntroductionPatients and methodsResultsDiscussionReferences |
|---|
Objective. Surgery can prevent extensor tendon rupture in the rheumatoid wrist but it is difficult to identify patients at risk. Extensor digiti minimi (EDM) usually ruptures first, but rupture may pass unnoticed because extensor digitorum communis (EDC) extends all four fingers simultaneously. We assessed the value of screening for EDM rupture by examining for absent independent extension of the little finger in a hospital rheumatoid arthritis population.
Methods. The EDM test was performed in 550 previously unoperated wrists. Disease activity, joint damage, wrist swelling, tenderness and crepitus were recorded.
Results. Unsuspected EDM loss was found in nine of the 550 wrists (1.6%); dorsal synovitis was absent or minimal in eight and ulnar tenderness was absent in six. EDM loss was not associated with activity, severity or duration of disease.
Conclusions. The EDM test is simple and cheap. It may identify patients at risk and permit prophylactic surgery before hand function is lost.
KEY WORDS: Extensor tendon, Tendon rupture, Rheumatoid arthritis, Screening, OSRA.
|
Introduction |
|---|
|
TopAbstractIntroductionPatients and methodsResultsDiscussionReferences |
|---|
Rupture of the extensor tendons of the fingers is a common and disabling complication of rheumatoid arthritis. It results from tenosynovial invasion of tendons or, more commonly, from their attrition on the ulnar head [1].
Tenosynovectomy, with or without ulnar head surgery, is highly effective in preventing tendon rupture [2], whereas reconstruction of ruptured tendons often fails to restore full movement [3]. Unfortunately, it is difficult to identify patients who are at risk of rupture, which may occur without warning and without notable pain or swelling. Typically, rupture is sequential and begins in the little finger.
We have observed that wrists explored for recent rupture of extensor digitorum communis (EDC) tendons frequently have a more long-standing rupture of extensor digiti minimi (EDM). EDM produces independent extension of the little finger, but the loss of this action may pass unnoticed because the EDC tendons can extend all four fingers simultaneously in many hands [4]. Early detection of EDM rupture may permit prophylactic surgery before other tendons are damaged.
In order to assess the value of the EDM test (independent active extension of the little finger) in screening for risk of EDC tendon rupture, we examined the prevalence of EDM loss in a hospital rheumatoid arthritis population.
|
Patients and methods |
|---|
|
TopAbstractIntroductionPatients and methodsResultsDiscussionReferences |
|---|
Patients attending the rheumatology unit as out-patients or in-patients were invited to be screened for EDM rupture. Patients were asked specific questions about wrist pain and were examined for ulnar head tenderness and prominence, distal radio-ulnar joint (DRUJ) crepitus and extensor tenosynovitis. Extensor tenosynovitis was scored on a scale from 0 to 3. The EDM test was performed and recorded as present, absent, untestable or equivocal.
The EDM test was performed by asking the patient to make a fist and then to extend the little finger independently (Fig. 1
). If the patient found difficulty in maintaining flexion of the other digits, they were held passively in flexion by the examiner. The EDM tendon was scored as absent if the little finger showed no active extension at the metacarpophalangeal (MCP) joint while the other digits were flexed. If active extension was present but limited, it was scored as equivocal. The hand was scored as untestable if severe MCP joint disease precluded testing.
|
Demographic details were recorded. Disease activity and damage were assessed using the erythrocyte sedimentation rate (ESR) and the Stanford Health Assessment Questionnaire (HAQ) for rheumatoid arthritis [5]. In addition, the OSRA (Overall Status in Rheumatoid Arthritis) questionnaire was used to give a second assessment of disease activity and damage [6].
A specially trained nurse performed all the assessments. Patients in whom interpretation of the EDM test was uncertain were referred for further evaluation by the authors (LW and PB) before a final score was allocated.
Patients who were found to lack EDM action were referred to the combined medical/surgical clinic for assessment. They were informed that other tendons were likely to be at risk of rupture and offered prophylactic surgery (extensor tenosynovectomy with or without ulnar head excision). Ethical approval for the study was granted by the local research ethics committee.
Categorical data were analysed by the Fisher exact test. HAQ and other scores were analysed with the Mann–Whitney test and the Spearman rank correlation test.
The operation notes of 41 patients presenting with recent rupture of the EDC tendon prior to the screening study were reviewed to determine the prevalence of old ruptures of the EDM tendon. All operations were performed or supervised by PB. The operation notes were typed and specifically recorded the status of the EDM and EDC tendons.
|
Results |
|---|
|
TopAbstractIntroductionPatients and methodsResultsDiscussionReferences |
|---|
In the 41 consecutive cases explored for a recent rupture of at least one EDC tendon prior to the screening study, 31 also had a long-standing rupture of EDM.
During a 6-month period, 290 patients were examined. Thirty wrists that had undergone wrist surgery previously were excluded, leaving 550 wrists in the study. EDM function was untestable because of severe MCP joint disease in 15 hands (2.7%).
Unsuspected EDM loss was found in nine wrists (1.6%). Three patients declined surgery or were considered unfit for operation. Six wrists were explored; five of these had rupture of the EDM tendon associated with perforation of the distal radioulnar joint capsule, leaving the tendon in contact with the ulnar head. In one case, the tendon's excursion was restricted by fibrous adhesions to its sheath.
Patients who had lost EDM were not significantly different from other patients with respect to age, duration of disease, ESR, HAQ score and OSRA activity score. The frequency of wrist pain, ulnar head prominence, ulnar head tenderness and DRUJ crepitus was similar in the two groups (Table 1). Grading for extensor tenosynovitis was also similar (Table 2).
|
|
The mean HAQ score, OSRA activity and damage scores were all lower in patients with no wrist pain than in patients with pain in one or both wrists (Table 3
). Both the OSRA damage and activity scores were highly correlated with the HAQ; the HAQ and OSRA activity scores were highly correlated with the ESR (Table 4).
|
|
|
Discussion |
|---|
|
TopAbstractIntroductionPatients and methodsResultsDiscussionReferences |
|---|
Extensor tendon rupture is a common but potentially preventable cause of permanent functional loss in the rheumatoid hand. The sequential nature of extensor rupture, beginning with the little finger, reflects the role of the ulnar head in abrading the overlying tendons, as described in osteoarthritis of the distal radioulnar joint by Vaughan-Jackson [1]. Progressive damage to the distal radioulnar joint leads to perforation of its dorsal capsule, allowing the tendons to make contact with the roughened ulnar head.
The EDM tendon runs directly over the ulnar head, where the floor of its tendon sheath (the fifth dorsal compartment) is contiguous with the dorsal capsule of the distal radioulnar joint. The EDC tendons run in the fourth dorsal compartment, whose ulnar edge lies over the distal radioulnar joint. Perforation of the dorsal joint capsule allows the ulnar head to make contact with the EDM tendon and, subsequently, with the EDC tendons. As each tendon ruptures, its neighbour on the radial side is able to make contact with the ulnar head and ruptures in turn.
Radiographic evidence of distal radioulnar disease is common in the hospital rheumatoid arthritis population. These patients are at risk of extensor tendon rupture. Some have wrist pain that demands operations such as ulnar head excision or wrist arthrodesis. The risk of rupture is virtually eliminated by placing the extensor retinaculum beneath the extensor tendons of the fingers and thumb during these procedures. But it is difficult to justify prophylactic surgery in the large group of patients whose symptoms are controlled medically and whose level of risk of tendon rupture is modest.
A means of identifying patients at high risk is needed. Wrist pain, distal radioulnar crepitus, ulnar head prominence and tenderness each affected between one-fifth and one-third of the wrists in our study. These features were no more common in patients who had lost EDM. Although this study's ability to demonstrate risk factors for EDM loss is limited by the small number of EDM ruptures, the low frequency of pain, tenderness, crepitus and tenosynovitis is striking and conforms with clinical experience that premonitory signs of tendon rupture are infrequent. In this study, wrist pain correlated strongly with the OSRA activity score but very weakly with the OSRA damage score. The lack of association between tendon rupture and wrist pain is consistent with the usual mechanism of rupture, namely attrition on damaged bone rather than invasion by active synovitis.
The effect of EDM rupture on extension of the little finger is determined by the anatomy of the extensor apparatus and in particular by the effectiveness of the contribution from EDC, which is subject to considerable anatomical variation. A separate EDC tendon to the little finger (EDCV) was found in 3% of 240 dissected hands [4]. In the remaining hands, a junctura tendinum from the EDCIV joined the EDM in the extensor hood over the little MCP joint. In 83% of hands the contribution from the EDCIV to the little finger was long-oblique and tendinous, and presumably capable of extending the little finger in the absence of EDM. In 17% it was transverse and ligamentous; in these hands, loss of EDM would probably lead to a noticeable extension lag of the little finger. The two patients with isolated EDM loss that presented with an extension lag of the little finger presumably fell into this latter group.
The operative finding of old rupture of the EDM tendon in three-quarters of the wrists explored for recent EDC tendon rupture suggests not only that EDM is the first tendon to undergo rupture but also that its loss may pass unnoticed by patient and doctor. It is likely that EDM rupture is the first, but clinically silent, event in the sequence of tendon rupture. The next event is loss of the EDC tendon to the ring finger, resulting in a marked extension lag of both ring and little fingers. Our findings strongly suggest that loss of EDM tendon function is a valuable sign that other extensor tendons are at high risk of rupture.
Congenital absence of EDM appears to be very rare. Macalister [7] recorded that he had encountered absence of EDM in anatomical dissections. However, more recent anatomical studies, in which a total of 890 hands were examined, report no instance of absence [4, 8–14]. Therefore, if independent extension of the little finger is absent in a hand with satisfactory MCP joint function, rupture of the EDM tendon can be assumed.
Subluxation of the EDM tendon over the ulnar side of the MCP joint may mimic EDM loss. The subluxation, which is usually associated with ulnar drift, is often visible or palpable. If the MCP joint can be extended passively, the EDM tendon may return to its normal central location and hold the joint extended actively. A rare cause of loss of active MCP joint extension is compression of the posterior interosseous nerve by a rheumatoid synovial swelling at the elbow [15]. But it would be very unusual for compression to affect only the fibres destined for EDM.
The small proportion of patients found to have EDM loss may reflect the high awareness of the risk of tendon ruptures in our unit, which has a long-standing interest in surgical management of rheumatoid disease and holds a weekly combined medical/surgical hand clinic.
The indication for prophylactic surgery may be discussed with patients who are found to lack EDM tendon action. Further evidence of the risk of EDC rupture can be obtained by arthrography of the distal radioulnar joint. If contrast medium passes from the joint into the compartments of the EDM and/or EDC tendons, a capsular perforation is present, and it is likely that the tendons are in contact with the ulnar head (Fig. 2).
|
Our study confirmed the high correlations between the OSRA activity score and the HAQ and between the OSRA damage score and HAQ shown by others [16]. This is the largest cohort of patients from a single centre in which the OSRA has been used and compared with other measurements of disease activity and damage. The strong correlation between OSRA activity score and ESR has not previously been so clearly demonstrated.
The EDM test is simple, quick and free of cost. The detection rate is at least comparable with that of monitoring for complications of drug therapy. The test may be taught to patients, who can perform it weekly and seek advice promptly if EDM function is lost.
|
Acknowledgments |
|---|
We thank Mrs Diane Croft for performing the majority of the screening tests.
|
Notes |
|---|
Correspondence to: L. Williamson, Department of Rheumatology, Nuffield Orthopaedic Centre, Oxford OX3 7LD, UK
|
References |
|---|
|
TopAbstractIntroductionPatients and methodsResultsDiscussionReferences |
|---|
- Vaughan-Jackson OJ. Rupture of extensor tendons by attrition at the inferior radio-ulnar joint: report of two cases. J Bone Joint Surg Br1948;30:528–30.
- Brown FE, Brown ML. Long-term results after tenosynovectomy to treat the rheumatoid hand. J Hand Surg Am1988;13:704–8.[Medline]
- Moore JR, Weiland AJ, Valdata L. Tendon ruptures in the rheumatoid hand: analysis of treatment and functional results in 60 patients. J Hand Surg Am1987;12:9–14.[Medline]
- Wehbe MA. Junctura anatomy. J Hand Surg Am1992;17:1124–9.[Medline]
- Kirwan JR, Reeback JS. Stanford Health Assessment Questionnaire modified to assess disability in British patients with rheumatoid arthritis. Br J Rheumatol1986;25:206–9.
[Abstract/Free Full Text] - Symmons DP, Hassell AB, Gunatillaka KA, Jones PJ, Schollum J, Dawes PT. Development and preliminary assessment of a simple measure of overall status in rheumatoid arthritis (OSRA) for routine clinical use. Q J Med1995;88:429–37.
- Macalister A. Additional observations on muscular anomalies in human anatomy (third series) with a catalogue of the principal muscular variations hitherto published. Trans R Irish Acad1875;25:95–109.
- Von Schroeder HP, Botte MJ. Anatomy of the extensor tendons of the fingers: Variations and multiplicity. J Hand Surg Am1995;20:27–34.[Medline]
- Perkins RE, Hast MH. Common variations in muscles and tendons of the human hand. Clin Anat1993;6:226–31.
- Godwin Y, Ellis H. Distribution of the extensor tendons on the dorsum of the hand. Clin Anat1992;5:394–403.
- Nakashima T. An accessory extensor digiti minimi arising from extensor carpi ulnaris. J Anat1993;182:109–112.
- Mestdagh H, Bailleul JP, Vilette B, Bocquet F, Depreux R. Organization of the extensor complex of the digits. Anat Clin1985;7:49–53.[Medline]
- Schenk R. Variations on the extensor tendons of the fingers: surgical significance. J Bone Joint Surg Am1964;46:103–7.
[Abstract/Free Full Text] - Rupnik J, Leclercq C. Extensor tendons to the little finger: Anatomy and classification. Main1997;2:3–9.
- White SH, Goodfellow JW, Mowat A. Posterior interosseous nerve palsy in rheumatoid arthritis. J Bone Joint Surg Br1988;70:468–71.[Medline]
- Birrell FN, Hassell AB, Jones PW, Dawes PT. Why not use OSRA? A comparison of Overall Status in Rheumatoid Arthritis (RA) with ACR core set and other indices of disease activity in RA. J Rheumatol1998;25:1709–15.[Web of Science][Medline]
CiteULike 
Connotea 
Del.icio.us What's this?
This article has been cited by other articles:
|
|
 |
|
  M. J. Harrison, A. Hassell, P. T. Dawes, D. L. Scott, S. M. Knight, M. J. Davis, D. Mulherin, and D. P. M. Symmons The overall status in rheumatoid arthritis (OSRA) measure--further evidence to support its use in clinical practice Rheumatology, May 1, 2007; 46(5): 849 - 855. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. R. Papp, G. S. Athwal, and D. R. Pichora The Rheumatoid Wrist J. Am. Acad. Ortho. Surg., February 1, 2006; 14(2): 65 - 77. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. E. Ehrlich Extensor tendon rupture Rheumatology, July 1, 2002; 41(7): 831 - 831. [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||