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Keywords:

  • Silver ring splint;
  • Rheumatoid arthritis;
  • Dexterity;
  • Hand function;
  • SODA

Abstract

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Objective

To study the effect of Silver Ring Splints (SRSs) on hand function in patients with rheumatoid arthritis (RA).

Methods

RA patients with stable disease and finger deformities eligible for splinting received 1 or more SRSs. Primary outcome was dexterity, which was measured with the Sequential Occupational Dexterity Assessment (SODA). Secondary outcome measures were self-reported hand function (Dutch Arthritis Impact Measurement Scales 2), hand pain, grip and pinch strength, Disease Activity Score in 28 joints (DAS28), and patient satisfaction.

Results

Seventeen patients (median age 65 years; median disease duration 21 years) received a total of 72 SRSs. After 1 year, 48 SRSs were regularly used. Two patients dropped out because of adverse events related to SRSs. In the remaining 15 patients, SODA dexterity scores increased significantly (median 71 at baseline, 81 at 3 months, and 85 at 12 months), Wilcoxon signed ranks test P = 0.005 and P = 0.026. DAS28 scores did not change at 3 months and improved slightly after 12 months (–0.5; P = 0.019). Grip strength, self-reported hand function, and hand pain showed no significant changes. Eleven patients stated they would continue using their splints.

Conclusion

SRSs can improve dexterity in selected patients with rheumatoid hand deformities. For a satisfactory result, careful patient preassessment and optimal adjustment of SRSs are essential.


INTRODUCTION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Pain, stiffness, and joint deformity may cause a serious decrease in hand function for people with rheumatoid arthritis (RA). Characteristic finger deformities in RA are swan neck deformity, boutonnière deformity, and ulnar deviation and subluxation of metacarpophalangeal joints. Surgical correction of deformities (if necessary with implantation of joint prostheses) may yield significant improvement, especially regarding pain, realignment, and aesthetics (1–3). Range of motion is less influenced, and little is known about the effects of hand surgery on objective, quantifiable measures of hand function (4).

In some cases, finger orthoses may be a good alternative to surgery. One example of finger orthoses is the Silver Ring Splint (SRS), which was developed in 1985. SRSs are combinations of oval rings made of high-quality sterling silver. This material combines adequate strength and rigidity with an acceptable cosmetic appearance. SRSs are easy to clean, can be used in warm water, and rarely cause any skin allergy. In a comparative study, SRSs rendered equal functional results to thermoplastic orthoses, whereas they were valued better on aspects of comfort and cosmetics (5). However, to our best knowledge no data have been published on the effect of SRSs on hand function in RA patients. We would expect dexterity and other aspects of hand function to improve, but this remains to be proven. In one study, for example, wrist braces unexpectedly appeared to cause impaired instead of improved hand function (6). Therefore we decided to study the effect of SRSs on hand function in RA patients over a 1-year period.

PATIENTS AND METHODS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Patients.

Patients were selected from a single rheumatologist's practice at Medisch Spectrum Twente Hospital, Enschede, The Netherlands. Inclusion criteria were RA according to the American College of Rheumatology (formerly American Rheumatism Association) criteria (7), stable disease, and hand deformities for which SRSs seemed a treatment option in the opinion of the rheumatologist (JJR). The finger joints for which SRSs were considered were not actively inflamed because joint swelling makes it difficult to find the correct ring size. Data on disease duration and previous use of disease-modifying antirheumatic drugs (DMARDs) were collected by chart review.

Ethics.

The study was approved by the Medical Ethical Committee of the Medisch Spectrum Twente Hospital, Enschede.

SRS procedure.

Patients who gave informed consent were seen by an occupational therapist (LH-R) with 6 years' experience with RA patients and by G. van de Maazen (SRS importer for the Netherlands, GM Medical Bracing Inc., Loon op Zand, The Netherlands), a physiotherapist who had 8 years experience in prescribing and supplying SRSs. By consensus, they decided for which deformities an SRS might be appropriate, the SRS size was taken, and a temporary thermoplastic splint was made. If after a testing period of 4 weeks patients were positive about this temporary splint, the SRS size was measured again to check for changes in joint swelling. Subsequently, the SRS was ordered from the manufacturer (Silver Ring Splint Company, Charlottesville, VA). On delivery, the SRS size was checked and adjusted to obtain optimal fit. During followup, further adjustments were made if necessary. SRS costs were reimbursed by the patients' health insurance companies.

Measurements.

At the time of SRS delivery (T0), as well as after using them for 1 (T1), 3 (T2), and 12 months (T3), several measurements were taken.

Dexterity was observed by the occupational therapist using the Sequential Occupational Dexterity Assessment (SODA) (8), a test for bimanual dexterity with minimal interference from impairment of the elbow and shoulder. The SODA consists of 12 standardized tasks (6 unilateral, 6 bilateral) performed under controlled conditions. The observer rates the way in which a task is performed (4 = able to perform in the requested way; 1 = able to perform in a different way; 0 = unable to perform) and the level of difficulty (2 = not difficult; 1 = some difficulty; 0 = very difficult). For bilateral tasks, each hand is scored separately. The total score ranges from 0 (unable to perform any of the tasks) to 108 (able to perform all tasks as requested without difficulty). It was validated in RA patients (mean SODA score 85.2; SD 19.1; range 14–108) showing high internal consistency (Cronbach's α = 0.91), sufficient test–retest reliability, and sensitivity to change (8). It correlated significantly with disease duration, disease activity, hand mobility, grip strength, pain, and self-reported dexterity. The SODA pain score is assessed by counting the number of tasks that cause pain (range 0–12).

Grip strength was measured with a hand-size pressure balloon connected to a mercury manometer for measuring blood pressure. The balloon was prefilled to a pressure of 30 mm Hg. Patients were instructed to squeeze the balloon as hard as possible. The mean of 3 attempts was used. Pinch grip was measured with a pinch gauge (PG-60; BNL Engineering, Santa Fe Springs, CA). Patients were instructed to perform a fingertip pinch if possible. The mean of 3 attempts was recorded. Grip and pinch strength were only analyzed for the hands or finger-thumb pairs on which SRSs were worn.

Self-reported hand function was assessed using the hand and finger function subscale of the Dutch Arthritis Impact Measurement Scales 2 (AIMS2) (9), which consists of 5 questions regarding the patient's ability over the previous week to write with a pen or pencil, to button up a shirt or blouse, to turn a key in a lock, to knot a tie, and to open a new jar of food. Possible answers are all days, most days, some days, few days, and never. The scores are added and then converted to a score of 0 (good health) to 10 (bad health).

At T0, T2, and T3, the erythrocyte sedimentation rate was measured and 28 joint counts for swelling and tenderness were assessed by a rheumatologist (TRZ), who was blinded for the compliance data. Patients rated their general health on a 100-mm visual analog scale. From these 4 items, the Disease Activity Score in 28 joints (DAS28) (10) was calculated. The DAS28 score ranges from 0.14 to 9.3, with higher scores indicating higher RA disease activity. A change of at least 1.2 is considered clinically relevant.

During the first month, patients were asked to record the number of hours that they actually used the SRSs. At 3 and 12 months, they were asked whether they stopped using SRSs and for what reason. At T3, patients completing the study answered a questionnaire containing items on overall satisfaction, comfort, pain, cosmetics, effects on hand function, and willingness to continue wearing SRSs. The last question was whether patients regretted trying SRSs or instead wished they had had their SRSs much earlier.

Analysis.

For statistical analysis, the Statistical Package for the Social Sciences (SPSS Inc., Chicago, IL) was used. Differences from baseline were analyzed with a nonparametric test for paired samples (Wilcoxon's signed rank test). Observed dexterity (SODA) was the primary outcome measure. Our hypothesis was that both observed dexterity and secondary outcome measures (subjective dexterity, hand pain, and grip strength) would improve with SRS use.

RESULTS

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Of 29 patients who were asked to participate, 19 (66%) gave informed consent and 17 (59%) were eligible for the use of 1 or more SRS (14 women, 3 men; median age 65 years, range 37–74 years; median disease duration 21 years, range 3–41 years). All but 1 were right handed. At the time of the study, 14 patients (82%) used nonsteroidal antiinflammatory drugs, 14 (82%) were taking a stable dose of DMARD (7 methotrexate, 2 azathioprine, 2 hydroxychloroquine, 1 aurothioglucose, 1 D-penicillamine, 1 sulfasalazine), and 7 (41%) were taking a maintenance dose of 5–10 mg prednisolone. Medication did not change during the trial period.

These 17 patients were supplied with a total of 72 SRSs: 64 for proximal interphalangeal (PIP) joints, 5 for distal interphalangeal joints, and 3 for first interphalangeal joints (Table 1). Most patients received splints for both hands. In 4 patients (24%), it proved impossible to provide satisfactory SRSs for 1 or more fingers. In patient P, SRSs caused paraesthesiae in the fingertips. In patient Q, rheumatoid nodules developed on the PIP joints, which prevented the SRSs from passing the joints. These 2 patients could not tolerate their SRSs and dropped out of the study. They had low SODA and maximum AIMS2 scores at baseline, indicating poor dexterity. Patient P had a high DAS28 score at baseline but not at T2. Patient G experienced unpleasant pressure on bony joint edges and eventually used only 1 of her 6 SRSs. Patient H found the SRSs uncomfortable but gave no particular reason. In 6 other patients, minor modifications were necessary during the study. Of the original 72 SRSs, a total of 24 (33%) were discarded during the course of the year. The main reasons for discard were paraesthesiae (8 SRSs in patient P) and pressure from bony edges or rheumatoid nodules (6 SRSs in patients G and Q). In all cases, the patients themselves decided not to wear the splints.

Table 1. Overview of all SRSs studied, average time of use during the first month, modifications, and reasons for failure*
PatientLeft handRight handHours per dayModification, problem, or reason for failure
5432112345
  • *

    SRS = Silver Ring Splint; D = SRS for distal interphalangeal joint; P = SRS for proximal interphalangeal joint; I = SRS for interphalangeal joint of the thumb; R = right; X = failure; L = left.

A DDPI   D 12Buddy splint R-3-4-5 added afterward
BPPPP  PPP 5.5 
C  PP      6Uncomfortable while driving a car
D  PPI  PPP13 
E PP   P  PX5 
F  PP  PP P14 
G  PX  IXPXPDXPX6Pressure on bony joint edges, R1 broken
H PXPX    PXPX ?Unsatisfactory, no specific reason given
I      P   11 
J PX      P 10Poor fit despite adjustments
K DX    PP  14L4 kept slipping off the finger
LPPP    P  ?Buddy splint R-4-5 added afterward
MPPXPXP      9.5Lack of space between fingers
NP     PPP 8 
OPP P  P  P8L2 lost and replaced
PPXPXPXPX  PXPXPXPX13.5Paraesthesiae in all fingers, dropped out
Q       PXPX 14Growing rheumatoid nodules, dropped out

Individual results on dexterity, disease activity, and patient satisfaction are shown in Table 2. Group results of the 15 patients who completed the study are shown in Table 3. During followup, SODA scores improved by a mean of 9 points. At T2 and T3, the difference from baseline was statistically significant for patients still wearing their SRSs (Wilcoxon's signed rank test P = 0.005 and P = 0.026, respectively). SODA-pain showed no significant change, nor did grip or pinch strength. The Dutch AIMS2 hand and finger function subscale improved slightly after 1 month, (median 6.0 at baseline and 4.5 at 1 month on a 0–10 scale), but at T2 and T3 this improvement was not statistically significant.

Table 2. Individuals' results of SODA, AIMS2, DAS28 and patient satisfaction*
PatientSODAAIMS2DAS28Wished to continueWanted earlier
T0T1–T0T2–T0T3–T0T0T1–T0T2–T0T3–T0T0T2–T0T3–T0
  • *

    Results are presented as baseline values (T0) and change scores (T1, T2, and T3). High SODA scores indicate good dexterity; high AIMS2 scores indicate poor dexterity; high DAS28 scores indicate high disease activity. SODA = Sequential Occupational Dexterity Assessment; AIMS2 = Arthritis Impact Measurement Scales 2; DAS28 = Disease Activity Score in 28 joints; T1 = after 1 month; T2 = after 3 months; T3 = after 12 months.

  • The question was “Do you expect to continue wearing your Silver Ring Splint in the future?” The answers were: ++ = yes, definitely; + = yes, I think so; 0 = I do not know; − = no, I do not think so; −− = no, definitely not.

  • The question was “Looking back after 1 year of wearing your ring splints, what do you think?” The answers were: ++ = I wish I had gotten them much earlier; + = it is good to have them now; 0 = with or without them, it does not matter; − = if I had to decide now, I would not do it again; −− = I wish I had never started with those rings.

A71910116.5−2.5−0.5−1.05.50.4−1.1+++
B8920−44.50.50.02.05.8−0.10.000
C60919148.5−1.5−0.5−2.54.60.5−1.2+0
D62−10238.50.0−0.51.06.5−0.9−0.3++0
E708058.0−2.0−1.5−1.04.60.0−0.6++++
F50−2−2−46.00.00.00.54.1−1.8−0.7+++
G5378368.0−4.5−6.0−6.03.0−0.30.4++
H87−8693.5−1.01.51.04.5−1.6−0.3−−
I97−1630.50.0−0.501.80.0−0.1+
J834927.0−1.0−1.5−0.55.20.1−0.2++
K8671695.0−0.5−1.0−0.54.20.10.500
L2475236.53.53.52.05.7−0.6−0.9++++
M45168294.5−2.0−1.005.40.4−0.6+++
N98−4−4−43.00.00.0−0.54.9−0.9−0.8++
O9254−34.5−0.5−1.0−0.55.20.40.1++
P38−12  10.0−1.5  7.4−4.2   
Q59229 10.0−1.0−1.5 4.6−0.5   
Table 3. Results of hand function, grip strength, and disease activity for patients who completed the study (n = 15)*
 T0 (no SRS)T1 (1 month)T2 (3 months)T3 (12 months)
  • *

    Values are given as median (range). SRS = Silver Ring Splint. For definitions of other abbreviations, see Table 2.

  • P = 0.005 from baseline.

  • P = 0.026 from baseline.

  • §

    At T0, T1, and T2, 25 hands were assessed. Due to failing equipment only 17 hands could be assessed at T3.

  • Only hands in which SRSs were used on the thumb and/or index finger were included.

SODA71 (24–98)79 (31–97)81 (29–103)85 (46–100)
SODA change from baseline 5 (−10–16)6 (−4–19)5 (−4–36)
SODA pain3 (0–10)3 (0–10)2 (0–9)4 (0–10)
Dutch AIMS2 hand and finger function6.0 (0.5–8.5)4.5 (0.5–10.0)5.0 (0.0–10.0)5.5 (0.5–9.5)
Grip strength, mm Hg§96 (65–173)96 (68–164)85 (64–159)95 (54–165)
Pinch grip, kg (15 hands)8.5 (3.0–15.5)8.0 (3.0–16.5)9.0 (4.0–14.0)8.0 (3.0–18.0)
DAS284.9 (1.8–6.5) 5.1 (1.8–5.9)4.4 (1.7–6.2)

There was a statistically significant change in DAS28 at T3 (–0.5; P = 0.019), but only patient C showed a clinically relevant 1.2-point improvement at that time. None had significantly increased disease activity.

Fifteen patients completed the study and answered the questionnaire after 1 year. On a scale of 1–5, they scored a mean of 3 (indifferent) for overall satisfaction, comfort, pain, cosmetics, and effect on hand function. Eleven patients said they would continue to wear their SRSs, 2 expected not to wear them anymore, whereas 2 did not know. Six patients stated they would have liked to have had the SRSs much sooner.

DISCUSSION

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

Although most of our patients had severe longstanding hand deformities, we found that observed dexterity improved with a mean change of 9 points. In 7 patients, SODA scores improved by 9 points or more, which is considered a relatively good change (11). After hand surgery in RA patients, a mean improvement of 4.4 points was found (12), with largest improvement after metacarpophalangeal implant arthroplasty (8.7 points) and arthrodesis of fingers or thumb (10.0 points). In a 1-year observational study of 94 RA patients with a mean disease duration of 13 years, the SODA score decreased by a mean of 6 points (13). Compared with these data, the 9-point improvement after 1 year in our study may be considered quite remarkable.

Self-reported hand function (AIMS2) improved from 6.0 at baseline to 4.5 and 5.0 at T1 and T2, but this did not reach statistical significance, possibly due to the small study sample or a lack of sensitivity to change in the outcome measure. In the SODA, patients are asked to perform tasks in a specific manner, whereas in everyday life they may have adjusted to alternative ways of performing these tasks. Thus there may be a discrepancy between impairment as experienced by the patient and dexterity as observed by the occupational therapist. The mean DAS28 improved by 0.5 points during the study period, but this is unlikely to explain the SODA change. It has been shown that only 10% of the variation in the SODA score is related to disease activity (6).

Grip strength did not improve, which is hardly surprising considering the longstanding disease and the extent of hand deformities. Accurate pinch grip measurement was difficult in some patients due to extensive deformities or because the plain SRSs slipped from the metal surface of the pinch gauge. In future research, other methods may be considered to measure strength in separate fingers.

Most of our subjects received SRSs for both hands, so we could not examine if the effect of SRSs on dexterity is influenced by handedness. Limitations of this pilot study are its small sample size and the use of single observers.

Despite all efforts to make the splints fit as well as possible, 33% of SRSs were eventually considered failures. There are several explanations for this result. First, most of our patients had longstanding finger deformities, sometimes requiring large forces from SRSs to correct them, causing skin damage, pain, and paraesthesiae. Therefore, in our opinion SRSs can best be applied during the earlier stages of deformity, when correction is still relatively easy and progression of deformities may be prevented or slowed. However, it may be difficult to convince patients of the benefits of wearing SRSs when they have only minor deformities that do not cause much impairment.

Thickening of finger joints was a second problem. If the proximal ring of an SRS is large enough to pass a thickened joint, it is often too wide to fit properly on the proximal phalanx. Currently, this problem can be solved by using an SRS with a hinged proximal ring, but at the time of our study this construction was not yet available.

In our study, SRSs were ordered from the manufacturer according to standard shapes and sizes. If an SRS did not fit properly, the importer and the occupational therapist could make only small adjustments, or a new SRS had to be ordered. This procedure is unsatisfactory in complicated cases, in which we would prefer the patient to be assessed in the presence of the manufacturing silversmith, to work out the optimal solution to individual problems.

Finally, in this study all those finger deformities were treated for which the therapists believed SRSs to be a feasible solution. Had we focused on deformities that needed treatment from the patients' point of view, their motivation and satisfaction might have been better.

In conclusion, this pilot study shows that SRSs can significantly improve dexterity, even in patients with longstanding RA and severe hand deformities. SRSs may prove to be a simple, noninvasive, and relatively inexpensive alternative for hand surgery. Careful patient assessment by an occupational therapist in consultation with the treating physician, as well as correct timing and well-fitting splints, are necessary conditions for a satisfactory result.

Acknowledgements

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES

We thank the patients for their participation, Mr. G. J. van de Maazen for his cooperation, and E. Taal, PhD for his useful comments. Amicon Health Insurance Company reimbursed the costs of SRSs for the majority of the patients.

REFERENCES

  1. Top of page
  2. Abstract
  3. INTRODUCTION
  4. PATIENTS AND METHODS
  5. RESULTS
  6. DISCUSSION
  7. Acknowledgements
  8. REFERENCES
  • 1
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  • 2
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  • 3
    Shaw Wilgis EF. Distal interphalangeal joint silicone interpositional arthroplasty of the hand. Clin Orthop 1997; 342: 3841.
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    Prevoo MLL, van 't Hof MA, Kuper HH, van Leeuwen MA, van de Putte LBA, van Riel PLCM. Modified disease activity scores that include twenty-eight-joint counts: development and validation in a prospective longitudinal study of patients with rheumatoid arthritis. Arthritis Rheum 1995; 38: 448.
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    van Lankveld WGJM, Graff MJL, van 't Pad Bosch PJI. The short version of the Sequential Occupational Dexterity Assessment based on individual tasks' sensitivity to change. Arthritis Care Res 1999; 12: 41724.
  • 12
    van Lankveld W, van 't Pad Bosch P, van der Schaaf D, Dapper M, de Waal Malefijt M, van de Putte L. Evaluating hand surgery in patients with rheumatoid arthritis: short-term effect on dexterity and pain and its relationship with patient satisfaction. J Hand Surg [Am] 2000; 25: 9219.
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    van Lankveld WGJM, van 't Pad Bosch PJI, van de Putte L. Predictors of changes in observed dexterity during one year in patients with rheumatoid arthritis. Br J Rheumatol 1998; 37: 7339.