Foot Problems in Children with Juvenile Rheumatoid Arthritis (JRA)

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1 A Descriptive Study of Foot Problems in Children with Juvenile Rheumatoid Arthritis (JRA) Gayle Spraul and Gaye Koenning In this study, we evaluated the feet of 144 consecutive children with juvenile rheumatoid arthritis [IRA) during a routine outpatient visit to discover patterns of foot problems. We found that all but nine subjects had at least 1 of 21 foot problems, categorized as inflammation, limitation of motion, and abnormal alignment. Overall, pronated rearfoot and midfoot were observed in 73% and 72% of IRA patients, respectively. Additionally, 36% had splayfoot, whereas 35% of subjects had ankle limitation of motion. Other common foot problems included pronated forefoot, rearfoot and forefoot synovitis, forefoot limitation of motion, and toe valgus. Significant differences in the occurrence of various foot problems were observed among JRA onset/course subgroups and were influenced by both age and disease duration. Specifically, subjects with polyarticular JRA had more forefoot limitation and toe valgus, whereas subjects with pauciarticular JRA had pronated forefoot more often. Ankle limitation of motion, although unrelated to the JRA subgroup, was related to the duration of JRA. Subjects with longer disease histories also had toe valgus more often. Conversely, forefoot limitation of motion seemed to be more a function of age than of disease duration. These results indicate that foot problems are Gayle Spraul. MOT, OTR, MS, PT, is at the Rheumatology Department, Physical Medicine and Rehabilitation Department, Texas Children s Hospital; and Gaye Koenning, MS, RD, is at the Rheumatology Department, Texas Children s Hospital, Houston, Texas. Address correspondence to Gayle Spraul, MOT, OTR, MS, PT, Texas Children s Hospital, 6621 Fannin; MC , Houston, TX Submitted for publication April 6, 1994; accepted May 8, by the American College of Rheumatology. 144 common in the JRA population, and they underscore the need for thorough evaluation and physical therapy management. Key Words: Juvenile rheumatoid arthritis; Foot; Foot deformities. Foot problems have been estimated to occur in as many as 90% of adults with longstanding rheumatoid arthritis and are a significant source of functional disability [l-31. Children with juvenile rheumatoid arthritis (JRA) may also experience pain and arthritis of the foot and exhibit gait abnormalities [ However, data are not available that quantitate specific foot problems and their relationship to variables such as IRA subtype, age, and duration of illness, which may be important predictors of functional outcome. LITERATURE REVIEW Most early reports of foot problems in children with JRA are from descriptive studies of clinical manifestations of disease. Schaller and Wedgwood [4] described a clinical series of 124 children with JRA and noted involvement of knees, ankles, wrists, and feet in almost all of 46 patients with polyarticular (poly) JRA. Ankle involvement was observed in 26 with pauciarticular (pauci) JRA, and toe involvement was noted in 7. In a report by Ansell and Wood [5] on the clinical manifestations of 240 patients with JRA within the first year of active disease, 40% had ankle arthritis, 27% had arthritis of the subtalar and midtarsal joints, and 9% had metatarsophalangeal arthritis. In a 1988 review, Ansell and Swann [6] described patterns of foot problems according to JRA subtype. In patients with systemic JRA, the third most common site of arthritis was symmetrical involvement of the midtarsal joints, with persistent disease activity leading to metatarso /94/$5.00

2 Arthritis Care and Research Foot Problems in Children with Juvenile Rheumatoid Arthritis [JRA) 145 phalangeal joint involvement. Patients with seropositive poly JRA had early symmetrical erosive changes that affected metatarsophalangeal joints, with later involvement of the hindfoot. The ankle was the second most common site of arthritis in children with pauci JRA and was often associated with hindfoot involvement. No quantitative information was provided on the frequency of these foot problems according to JRA subtype. In a review of foot problems in children with JRA, Rana [7] reported that joint effusion, synovitis, bony demineralization, and growth disturbances were common and could ultimately lead to a variety of foot deformities. Gait deviations in children with JRA have been described in several studies. Dhanendran et al. [8] evaluated force distribution under the foot of the JRA patient and observed significantly reduced loading under the toes and the two medial metatarsal heads, as well as increased heel contact time, compared with healthy children. Witemeyer et al. [9] studied the time-distance variables of the gait pattern of children with JRA and found that those with severe joint disability suffered marked deviations from normal gait; the degree of disability and specific gait deviations, however, were not described. Lechner et al. [lo] compared the time-distance characteristics and joint angle excursions of 30 children with JRA and 30 healthy children. They reported that subjects with JRA walked with significantly decreased velocity, cadence, and stride length and had significantly increased anterior pelvic tilt throughout the gait cycle. Subjects were also reported to have significantly decreased hip extension at the end of single-limb stance, as well as decreased ankle plantarflexion during weight release. PATIENTS AND METHODS Subjects Informed consent for the foot study was obtained from 144 consecutive outpatients and parents attending a routine appointment in the Rheumatology clinic at Texas Children's Hospital between December 1989 and July Subjects were primarily white (76.4%) and female (81.2%)(mean age years]. Each patient was classified at enrollment according to one of four subgroups describing JRA disease onset and disease course: 36 (25%) pauciarticular onset and course (pauci) JRA, 66 (46%) polyarticular onset and course (poly) JRA, 16 (11?70] pauciarticular onset with polyarticular course (pauci/poly) JRA, and 26 (18%) systemic JRA. Disease duration was from 6 months to 17.3 years (mean 5.2 k 3.7 years). Foot Evaluation Protocol The protocol for foot evaluation included placing subjects in a supine position on an exam table with ankles in neutral position. Passive range of motion of the ankle (including dorsiflexion, plantarflexion, inversion, and eversion] was measured using a goniometer (Table 1). Measurements were compared to lower extremity norms, as established by the American Academy of Orthopaedic Surgeons [ll] for dorsiflexion, plantarflexion, and inversion. Norms by Kendall and McCreary [12] were used to evaluate eversion of the ankle. These adult joint motion guides were used due to the absence of joint motion guides specific to the pediatric population. Subjects with less than the standard measurements for either dorsiflexion (20'1, plantarflexion (50'1, inversion (35'1, or eversion (20") were considered to have limitation of motion of the ankle. With the subject in a supine position, passive range of motion of the forefoot, including metatarsophalangeal and interphalangeal joints, was evaluated subjectively according to the American Academy of Orthopaedic Surgeons' [ll] norms. Similarly, the presence or absence of enthesitis, rearfoot synovitis, forefoot synovitis, tenosynovitis, and plantar fasciitis was observed and palpated by the physical therapist (Table 1). Study subjects were then asked to stand on a flat surface. Each was positioned in correct postural alignment bearing full weight equally distributed over both feet. The therapist viewed both feet from the front, back, and side, and recorded the presence of any of the remaining 14 specific foot problems, categorized as abnormal alignment (Table 2). A foot problem was recorded as being present in the left, right, or in both feet. Data Analysis Independent variables for this study were age, sex, race, disease duration, and JRA onset/course subgroups (pauci, poly, pauci/poly, systemic]. Dependent variables included the 21 foot evaluation parameters listed in Tables 1 and 2. Data were analyzed with software from the Statistical Analysis System (SAS) Institute. Chi-square contingency table (4 x 21 analyses were performed to test for differences in specific foot problems among JRA onset/course subgroups. Follow-up contrasts were performed for all significant chi-squares to identify where specific differences among JRA subgroups occurred. Finally, general linear modeling was used to determine if specific foot problems varied by the independent variables of age, sex, race, JRA subgroup, or duration of disease. A significance level of was used for the chi-square and general linear models.

3 146 Spraul and Koenning Vol. 7, No. 3, September 1994 TABLE 1 Joint Position, Motion, and Goniometric Alignment of Foot Limitation of Motion and Inflammation Parameters Goniometric alignment Limitation of motion Position Motion Stationary arm Moveable arm Criteria Ankle Plantarflexion Dorsiflexion Inversion Eversion Forefoot Great toe 2nd-5th toes Inflammation Enthesitis Forefoot synovitis Supine Rearfoot synovitis Supine Tenosynovitis Plantar fasciitis Supine with knee ex- Foot moved so that tended or slightly toes point down. flexed (~10"). Ankle in neutral position (90"). Supine with knee ex- Foot moved so toes tended or slightly point up. flexed ( ~10~). Ankle in neutral position (90"). Supine with knee ex- Sole of foot faces metended or slightly dially to limits of flexed (~10"). Ankle motion. Hip exterin neutral position nal rotation pre- (90"). vented. Supine with knee ex- Sole of foot faces lattended or slightly erally to limits of flexed (~10"). Ankle motion. Hip interin neutral position nal rotation is pre- (90"). vented. Parallel to midline of Parallel to 5th meta- <50 lateral aspect of tarsal. lower leg. Parallel to midline of Parallel to 5th meta- <20" lateral aspect of tarsal. lower leg. Perpendicular to toes Parallel to toes ~35' Perpendicular to toes Parallel to toes 1-5. < Supine with knee ex- Flexion: manually Not performed Not performed. Manipulation and obtended or slightly flexed MTP and IP. servation for limitaflexed (510"). Ankle Extension: manually Not performed. Not performed. tion of motion. and toe in neutral extended MTP. position (0"). Supine with knee ex- Flexion: manually Not performed Not performed. Manipulation and obtended or slightly flexed MTPs and servation for limitaflexed (~10"). Ankle IPS. Not performed. Not performed. tion of motion. and toe in neutral position (0'). Extension: manually extended MTPs and IPS. Supine or sitting Supine Supine Inflammation at insertions of tendons and ligaments to bone: pain on palpation. Inflammation of synovial membrane detected by palpation and observation for swelling of joints. Inflammation of synovial sheath covering tendon: detected by palpation of tendon near joint. Inflammation of plantar fascia usually at origin of attachment on calcaneus; pain is experienced in heel or arch of foot. Tenderness on palpation.

4 Arthritis Care and Research Foot Problems in Children with Juvenile Rheumatoid Arthritis (JRAJ 147 TABLE 2 Definition of Foot Abnormal Alignment Parameters* Abnormal alignment Pronated forefoot Pronated midfoot Pronated rearfoot Supinated forefoot Supinated rearfoot Forefoot abductus Forefoot adductus Splayfoot Toe valgus including hallux valgus Claw toes Hammer toes Mallet toes Cock-up toes MTP subluxation Definition Weight bearing on medial aspect of first metatarsal, forefoot in valgus position. Flattening of longitudinal arch, midfoot in valgus position. Calcaneus is everted, talus is adducted and plantarflexed heel in valgus position. Inversion of midtarsal joint and forefoot. Calcaneus inverted, talus abducted and dorsiflexed with or without elevation of arch foot is in varus position. Forefoot is abducted on the rearfoot or is displaced outward in relation to midline of lower leg. Forefoot is adducted on rearfoot or is placed inward in relation to the midline of the lower leg. First metatarsal displaced medially. Lateral deviation of toes. Hyperextension of MTP joints and flexion of PIP and DIP joints. Hyperextension of MTPs, flexion of PIP joints, and extension of DIP joints. Hyperextension of MTPs, flexion of PIP joints; DIP joints remain straight. Dorsal displacement of proximal phalanx on metatarsal head. Complete dislocation of phalanx on the metatarsal head. * MTP = metatarsophalangeal, PIP = proximal interphalangeal, DIP = distal interphalangeal RESULTS Table 3 shows the frequency of the nine most common foot problems for the 144 JRA study subjects combined, as well as the four JRA disease onset/course subgroups. Pronated rearfoot and pronated midfoot were common findings, occurring, respectively, in 73% and 72% of all JRA patients. Splayfoot and ankle limitation of motion were observed in approximately onethird of the combined JRA subgroups. Pronated forefoot and synovitis of the rearfoot were both observed in 28% of the study subjects combined, whereas forefoot limitation of motion, toe valgus, and synovitis of the forefoot were seen in 2270, 17%, and 1670, respectively, of all subjects. The remaining 12 foot problems occurred in all subjects with a frequency of less than 8% and are not presented in Table 3. Initially, chi-square analyses were based on foot problems classified trichotomously as: not occurring, occurring in one foot, or occurring in both feet. How- ever, because of the high frequency of comparisons with expected cell counts of <5, the chi-square values presented in Table 3 are based on a dichotomous classification of foot problems (present or absent]. Chisquare analyses did not reveal significant differences in the occurrence of pronated rearfoot, pronated midfoot, splayfoot, or ankle limitation of motion among the four JRA onset/course subgroups. However, in contrast to the pronated rear and midfoot, splayfoot, and ankle limitation of motion problems, significant differences were found among the four JRA onset/ course subgroups for less common foot problems (pronated forefoot, forefoot limitation of motion, and toe valgus). Additionally, the chi-square for synovitis of the rearfoot approached significance (x2t31 = 7.38; P , thus suggesting a difference among the four JRA onset/course subgroups for this foot problem. It should be noted that chi-square analyses for toe valgus and forefoot synovitis in Table 3 must be interpreted with caution because >25% of the cells had expected counts <5, potentially underestimating the type I error. Contrasts using chi-square were conducted to determine if subsets of the original four JRA onset/course classifications were similar with respect to the occurrence of pronated forefoot, forefoot limitation of motion, and toe valgus. Results indicated that the poly subgroup was most likely to have forefoot limitation of motion (xz(ll = 11.24; P I 0.001) and toe valgus = 17.75; P I 0.001) than the combined pauci, systemic, and pauci/poly subgroups. In contrast, the pauci subgroup was most likely to have problems with pronated forefoot than the pauci/poly, systemic, and poly subgroups combined (xz(ll = 4.62; P I 0.03). Thus, although the pauci/poly subgroup was most like the pauci subgroup, with regard to its low frequency of forefoot limitation of motion and toe valgus, it was more like the poly subgroup with respect to its low occurrence of pronated forefoot. General linear modeling was used to address the question of whether specific foot problems were associated with the independent variables of age, race, gender, JRA subtype, and duration of illness. No relationships were found between any of the 21 specific foot problems and gender or race. However, both age and duration of illness were related significantly to several foot problems. Specifically, ankle limitation of motion was related to duration of JRA [F(3,140) = 4.24; P I but not to age. The relationship between ankle limitation of motion and duration of JRA did not appear to be confounded by age. Forefoot limitation of motion was significantly related to both duration of illness [F(l, 142) = 4.07; P and age [F(1,142) = 7.40; P Subjects with forefoot limitation of motion tended to be older (12.6

5 148 Spraul and Koenning Vol. 7, No. 3, September 1994 TABLE 3 Common Foot Problems All JRA Pauci Poly Pauci/Poly Systemic n = 144 (TO) n = 36 (YO) n = 66 ("r,) n = 16 (%) n = 26 (TO) Chi-square Pronated rearfoot Pronated midfoot Splayfoot Ankle LOM Pronated forefoot Rearfoot synovitis Forefoot LOM Toe valgus Forefoot synovitis 105 (73) 103 (72) 52 (36) 50 (35) 40 (28) 40 (28) 32 (22) 25 (17) 23 (16) 28 (78) 26 (72) 14 (39) 7 (19) 15 (42) 5 (14) 3 (8) 0 (01 2 (5) 45 (68) 46 (70) 20 (30) 28 (42) 15 (23) 21 (32) 23 (35) 21 (32) 15 (23) 21 (81) 20 (77) 10 (38) 9 (35) 9 (35) ) 6 (23) 4 (15) 3 (12) " 7.38b 14.69" 20.61m 5.63 LOM, limitation of motion. Chi-square significant at P Chi-square approached significance at 0.05 < P < years) and had JRA for a longer period (6.35 years) than subjects with no forefoot limitation of motion (10.03 years of age and 4.85 years JRA duration). Logistic regression results indicated that age contributed more to forefoot limitation of motion than did duration of JRA. Toe valgus was also related to duration of illness [F(1,142) = 12.89; P and to age [F(1,142) = 6.80; P = Logistic regression indicated that duration of JRA was more often a predictor of toe valgus than was age. Those subjects with toe valgus tended to have had JRA for a longer period (7.5 years) than those without toe valgus (4.7 years). As a final analysis, logistic regression was used to determine if the relationships observed in the chisquare analyses among JRA subgroup and toe valgus, limitation of motion of the forefoot, and pronated forefoot were independent of subject age and duration of illness. Results showed that both age (x2(11 = 4.75; P I 0.05) and type of JRA (classified as poly or non-poly) (x2(11 = 8.45; P ) were predictors of forefoot limitation of motion. Both duration (xz(l) = 13.31; P ) and type of JRA (poly or non-poly) (x2(11 = 15.48; P ) predicted toe valgus. Thus, in general, having poly JRA or being older was associated with a higher frequency of forefoot limitation of motion, whereas having poly JRA or having had JRA longer was associated with toe valgus. Pronated forefoot, although associated with pauci JRA in the chi-square analysis, was independent of age and duration of illness. DISCUSSION The high frequency of foot problems observed in this cross-sectional study is similar to that reported by Calabro [3] and Vainio [13] among adults with rheumatoid arthritis, in which 91% of 618 females and 85% of 337 males had rheumatoid involvement of the foot. However, important differences in the location of foot problems were observed among children with JRA in this study when compared to published reports in adults with rheumatoid arthritis (RA). Specifically, adults with RA have been reported to have a greater frequency of forefoot problems, including hallux valgus (70% vs 17701, hammer toes (80% vs <8%), and metatarsophalangeal subluxation (67% vs <8%) [14]. With regard to midfoot problems (e.g., flat feet), adults with RA have been reported to have a similar frequency when compared with JRA subjects in this study (66% and 7270, respectively) [l]. Table 4 contains a summary of the clinical significance of foot problems in children with JRA and their treatment. The high frequency of JRA patients in this study with pronated rearfoot and midfoot was unexpected because excessive pronation during weightbearing is a common finding in healthy children only up to about 6 years of age. Plotkin and Della Corte [15] reported that excessive pronation is found in per 100 children aged 1.5 to 3 years; this value decreases to 4 per 100 in older children and adults. However, excessive pronation beyond 6 years of age is considered abnormal [15,16]. Because the overall mean age for the JRA subjects in this study was 10.6 years (and >8.5 years among the four subgroups), the high frequency of pronation found in this study is unlikely to be related only to normal foot development. All other foot problems listed in Table 3 are unrelated to normal foot development and should be considered as abnormal findings. Limitations of this study include a lack of pediatric norms for goniometry, lack of data collection on se-

6 Arthritis Care and Research Foot Problems in Children with fuvenile Rheumatoid Arthritis [IRA) 149 TABLE 4 Clinical Significance and Treatment of Foot Problems in Children with JRA Forefoot adductus Hallux valgus with or without bunion Limited ankle dorsiflexion Limited ankle plantarflexion Limited ankle inversion/eversion Pronated foot (rear and midfoot) Pronated forefoot Supinated forefoot Mallet toes Hammer and claw toes Splayfoot Toe valgus Cock-up toes and MTP subluxation Forefoot abductus Enthesitis/tenosynovitis/plantar fasciitis Forefoot/rearfoot synovitis Clinical significance In-toe gait; biomechanical stresses on foot; supination of foot; increased risk of bunion deformities; difficulty fitting shoe gear. Internal gait disturbances; limb length inequality; pronated foot. Gait deviation-premature heel-off. flexed knees, or severe flat foot. Gait deviation-decreased toe-off. Gait may be affected, primarily uneven surfaces. Shoe irritation; painful bursitis; posterior tibia1 tendonitis; possible adult sequelae-bunions; hammer toes; fasciitis. Bunions; submetatarsal calluses; hammer toes; heel spur syndrome; post heel irritation. Callus formation. Nail deformity; corns. Corns; calluses; bursitis; metatarsalgia; painful gait. Callus formation; submetatarsal bursitis; stress fractures; dorsal dislocation and subluxation of 2nd and 3rd toes resulting in claw deformity; metatarsalgia. Callus formation; painful toes; painful gait. Metatarsalgia; pain due to shoe impingement. Pronated foot. Painful functional mobility, i.e., gait, standing. Painful feet; painful functional mobility, i.e., gait, standing. Treatment Stretching exercise; serial casting; straight last shoe with medial wedge heel. Address biomechanical causes of excessive pronation; functional orthotics; hallux abduction exercises; surgical intervention. Heelcord stretching. Range of motion exercise. Range of motion exercise. Stretching of contracted muscle; proper fitting shoes; functional orthotic heel wedges; treatment of inflammation, i.e., bursitis, tendonitis; foot intrinsic muscle strengthening. Foot intrinsic muscle strengthening; orthotics; palliative care for calluses; surgical correction. Palliative care for calluses; foot orthotics. Footwear with extra depth toe box & crepe soles; metatarsal bar or pad; palliative care for corns; stretching exercise; surgical correction. Modifications with padding; toe crest pad plantar splint; footwear with extra depth toe box; inlaid depth shoes; surgical correction. Palliative care for calluses; treat pain and discomfort; foot orthotics. Palliative care of callus; modifications with padding; footwear with extra depth toe box. Footwear with extra depth toe box; metatarsal pad/bar; surgical intervention; foot orthotics; toe extensor stretching; toe flexor strengthening. Foot orthotics; proper fitting shoes; foot intrinsic strengthening. Cold/ice; stretching; massage: rest. Anti-inflammatory medications as prescribed by MD; gentle range of motion. verity ratings for disease and associated treatment regimens, possible investigator error in reporting mild findings, and possible selection bias due to more severely ill patients followed at a tertiary care center. Lack of inter- and intrarater reliability measures is a limitation of this study, as well as other studies of the JRA population. Suggestions for future study include collection of information on disease severity and treatment as covariates in the analysis of foot problems in the JRA population, and correlation of foot problems with functional status using established measures, such as the Juvenile Arthritis Functional Assessment Scale [17], which was not available at the time this study was

7 150 Spraul and Koenning Vol. 7, No. 3, September 1994 conducted. Controlled studies addressing the efficacy of exercise, orthotics, and orthopedic management of the JRA foot are also needed. In summary, this study demonstrated a high frequency of JRA-related foot problems, suggesting the need for regular physical therapy to monitor and correct for foot deformities and to reduce foot-associated disability among children with chronic arthritis which persists into adulthood. We thank Ed Giannini, DrPH, for assistance with the design of this study, Paul Swank, PhD, for statistical advice, Bob Warren, MD, PhD, and Carol Kohn for review of the manuscript, and Monica Burns, BS, for manuscript preparation. REFERENCES 1. Coughlin MJ: The rheumatoid foot. Postgrad Med 75: , Vidigal EC, Jacoby RK: The foot in chronic rheumatoid arthritis. Ann Rheum Dis , Calabro JJ: A critical evaluation of the diagnostic features of the feet in rheumatoid arthritis. Arthritis Rheum 5:19-29, Schaller J, Wedgwood R: Juvenile rheumatoid arthritis: a review. Pediatrics 50: , Ansell BM, Wood P: Prognosis in juvenile chronic polyarthritis. Clin Rheum Dis , Ansell BM, Swann M: Juvenile arthritis. In Helal B (ed): The Foot. New York, Churchill Livingston, Rana N: Juvenile rheumatoid arthritis of the foot. Foot Ankle 3:2-11, Dhanendran M, Hutton WC, Klenerman L, Witemeyer S, Ansell BM: Foot function in juvenile chronic arthritis. Rheum Rehab 19:20-24, Witemeyer S, Ansell BM, Ashburn A, Wall J, Klenerman L: Gait analysis: a pilot study-a possible mode of assessment of lower limb function in juvenile chronic arthritis. Rheum Rehab 20:31-37, Lechner D, McCarthy C, Holden M: Gait deviations in patients with juvenile rheumatoid arthritis. Phys Ther 67~ , American Academy of Orthopaedic Surgeons: Joint Motion: Method of Measuring and Recording. Chicago, American Academy of Orthopaedic Surgeons, Kendall FP, McCreary EK: Muscles: Testing and Function. Baltimore, Williams & Wilkins, Vainio S: The rheumatoid foot: a clinical study with pathological and roentgenological comments. Ann Chir Gynaecol Fenn 45(Suppl 1):l-107, Vidigal EC: Forefoot in chronic rheumatoid arthritis. Orthop Rev 7:43-46, Plotkin S, Della Corte MP: Pediatrics. In Birrer R, Della Corte MP, Grisafi PJ (eds): Common Foot Problems in Primary Care. Philadelphia, Hanley & Belfus, Inc, Tax HR: Podopediatrics, 2nd ed. Baltimore, Williams & Wilkins, Love11 DJ, Howe S, Shear E, Hartner S, McGirr G, Schulte M, Levinson J: Development of a disability measurement tool for juvenile rheumatoid arthritis. Arthritis Rheum 32: , 1989.