1. Background
2. Objectives
3. Methods
3.1. Patients and Setting
3.2. Data Gathering
3.3. Diagnostic Definitions and Adjudication
3.4. Operational Definitions and Variable Categorization
3.5. Statistical Analysis
4. Results
4.1. Etiology of Limping
| Final Diagnosis | No (%); 95% CI |
|---|---|
| Reactive arthritis | 42 (25.3); 18.9 - 32.6 |
| Viral myositis | 34 (20.4); 14.6 - 27.4 |
| Transient synovitis | 17 (10.2); 6.1 - 15.9 |
| Septic arthritis | 17 (10.2); 6.1 - 15.9 |
| Guillain-Barré syndrome | 11 (6.6); 3.6 - 11.6 |
| Cellulitis | 9 (5.4); 2.8 - 10.2 |
| New lesion b | 7 (4.2); 1.7 - 8.5 |
| Complication from underlying disease | 3 (1.8); 0.4 - 5.2 |
| Acute rheumatic fever | 3 (1.8); 0.4 - 5.2 |
| Brucellosis | 2 (1.2); 0.1 - 4.3 |
| Growing pain | 2 (1.2); 0.1 - 4.3 |
| Osteomyelitis | 2 (1.2); 0.1 - 4.3 |
| Multisystem inflammatory syndrome in children | 2 (1.2); 0.1 - 4.3 |
| Juvenile idiopathic arthritis | 1 (0.6); 0.02 - 3.3 |
| Transient, self-limiting conditions | 14 (8.4); 4.7 - 13.8 |
a Abbreviations: JIA, juvenile idiopathic arthritis; MIS-C, multisystem inflammatory syndrome in children.
b New bone-joint lesion during the course of an underlying disease included 4 cases of acute lymphocytic leukemia, 2 cases of Langerhans cell histiocytosis, and 1 case of primitive neuro-ectodermal tumor.
| Final Diagnosis | Male | Female | Age (y) | 1 - 3 (y) | 4 - 7 (y) | 8 - 18 (y) |
|---|---|---|---|---|---|---|
| Reactive arthritis (n = 42) | 22 (52.3) | 20 (47.6) | 2.7 ± 5.2 | 13 (30.9) | 23 (54.7) | 6 (14.2) |
| Viral myositis (n = 34) | 27 (79.4) | 7 (20.5) | 2.0 ± 6.5 | 3 (8.8) | 20 (58.8) | 11 (32.3) |
| Transient synovitis (n = 17) | 9 (52.9) | 8 (47.0) | 2.3 ± 4.6 | 7 (41.1) | 8 (47.0) | 2 (11.7) |
| Septic arthritis (n = 17) | 9 (52.9) | 8 (47.0) | 3.7 ± 6.1 | 6 (35.2) | 7 (41.1) | 4 (23.5) |
| Guillain-Barré syndrome (n = 11) | 9 (81.8) | 2 (18.1) | 4.2 ± 8.1 | 1 (9.0) | 5 (45.4) | 5 (45.5) |
| Cellulitis (n = 9) | 5 (55.5) | 4 (44.4) | 2.9 ± 5.2 | 3 (33.3) | 5 (55.5) | 1 (11.1) |
| New lesion (n = 7) | 5 (41.4) | 2 (28.5) | 3.1 ± 6.4 | 2 (28.5) | 2 (28.5) | 3 (42.8) |
a Values are expressed as No. (%) or mean ± SD.
4.2. Clinical Characteristics and Joint Involvement
| Final Diagnosis | Fever | Joint Pain | Lower Limb Pain | Joint Movement Limitation | Tenderness | Decreased Muscle Strength | Swelling | Limb Weakness |
|---|---|---|---|---|---|---|---|---|
| Reactive arthritis (n = 42) | 26 (61.9); 45.6 - 76.4 | 40 (95.2); 83.8 - 99.4 | 1 (2.3); 0.1 - 12.6 | 18 (42.8); 27.7 - 59.0 | 13 (30.9); 17.6 - 47.1 | 5 (11.9); 4.0 - 25.6 | 7 (16.6); 7.0 - 31.4 | 4 (9.5); 2.7 - 22.6 |
| Viral myositis (n = 34) | 15 (44.1); 27.2 - 62.1 | 1 (2.9); 0.1 - 15.3 | 30 (88.2); 72.5 - 96.7 | 0 (0); 0 - 10.3 | 7 (20.5); 8.7 - 37.9 | 7 (20.5); 8.7 - 37.9 | 0 (0); 0 - 10.3 | 3 (8.8); 1.9 - 23.7 |
| Transient synovitis (n = 17) | 5 (29.4); 10.3 - 56.0 | 17 (100); 80.5 - 100 | 0 (0); 0 - 19.5 | 8 (47.0); 23.0 - 72.2 | 6 (35.2); 14.2 - 61.7 | 0 (0); 0 - 19.5 | 2 (11.7); 1.5 - 36.4 | 0 (0); 0 - 19.5 |
| Septic arthritis (n = 17) | 14 (82.3); 56.6 - 96.2 | 17 (100); 80.5 - 100 | 0 (0); 0 - 19.5 | 10 (58.8); 32.9 - 81.6 | 6 (35.2); 14.2 - 61.7 | 0 (0); 0 - 19.5 | 6 (35.2); 14.2 - 61.7 | 0 (0); 0 - 19.5 |
| Guillain-Barré syndrome (n = 11) | 0 (0); 0 - 28.5 | 1 (9.0); 0.2 - 41.3 | 3 (27.2); 6.0 - 61.0 | 0 (0); 0 - 28.5 | 1 (9.0); 0.2 - 41.3 | 7 (63.6); 30.8 - 89.1 | 0 (0); 0 - 28.5 | 9 (81.8); 48.2 - 97.7 |
| Cellulitis (n = 9) | 3 (33.3); 7.5 - 70.1 | 1 (11.1); 0.3 - 48.2 | 7 (77.7); 40.0 - 97.2 | 0 (0); 0 - 33.6 | 4 (44.4); 13.7 - 78.8 | 0 (0); 0 - 33.6 | 8 (88.8); 51.8 - 99.7 | 0 (0); 0 - 33.6 |
| New lesion (n = 7) | 3 (42.9); 9.9 - 81.6 | 3 (42.9); 9.9 - 81.6 | 3 (42.9); 9.9 - 81.6 | 2 (28.6); 3.7 - 71.0 | 0 (0); 0 - 41.0 | 2 (28.6); 3.7 - 71.0 | 0 (0); 0 - 41.0 | 4 (57.1); 18.4 - 90.1 |
a Values are expressed as No (%); 95% CI.
| Joint Involvement | Reactive Arthritis | Viral Myositis | Transient Synovitis | Septic Arthritis | Guillain-Barré Syndrome | Cellulitis | New Lesion |
|---|---|---|---|---|---|---|---|
| One joint | 23 (54.7) | 0 (0) | 13 (23.5) | 13 (23.5) | 1 (9.0) | 1 (11.1) | 2 (28.5) |
| More than one joint | 17 (40.4) | 1 (2.94) | 4 (23.5) | 4 (23.5) | 0 (0) | 0 (0) | 1 (14.2) |
a Values are expressed as No. (%).
4.3. Patient History
| Final Diagnosis | History of Specific Medication | Diarrhea | Recent URI | Trauma | Unpasteurized Dairy Consumption |
|---|---|---|---|---|---|
| Reactive arthritis (n = 42) | 24 (55.8) | 5 (11.9) | 18 (42.8) | 4 (9.5) | 4 (9.5) |
| Viral myositis (n = 34) | 26 (76.4) | 0 (0) | 29 (85.2) | 0 (0) | 2 (5.8) |
| Transient synovitis (n = 17) | 5 (29.4) | 0 (0) | 10 (58.5) | 2 (11.7) | 4 (23.5) |
| Septic arthritis (n = 17) | 9 (52.9) | 1 (5.8) | 4 (23.5) | 5 (29.4) | 4 (23.5) |
| Guillain-Barré syndrome (n = 11) | 5 (45.4) | 2 (18.1) | 7 (63.6) | 2 (18.1) | 0 (0) |
| Cellulitis (n = 9) | 5 (55.5) | 0 (0) | 0 (0) | 6 (66.6) | 0 (0) |
| New lesion (n = 7) | 1 (14.2) | 0 (0) | 0 (0) | 2 (28.5) | 1 (14.2) |
aValues are expressed as No (%). Abbreviation: URI, upper respiratory infection.
4.4. Laboratory and Imaging Findings
| Final Diagnosis | WBC (per mm3) | Leukocytosis | ESR (mm/h) | Raised CRP (≥ 10 mg/dL) | Platelet (×1000/mm3) | Thrombocytosis (> 450000/mm3) |
|---|---|---|---|---|---|---|
| Reactive arthritis (n = 42) | 11500 ± 3422 | 18 (42.8) | 43.0 ± 30.5 | 25 (59.5) | 322.5 ± 79.4 | 5 (11.9) |
| Viral myositis (n = 34) | 5241 ± 3034 | 1 (2.9) | 20.5 ± 15.2 | 8 (23.5) | 190.8 ± 67.3 | 0 (0) |
| Transient synovitis (n = 17) | 9800 ± 2776 | 4 (23.5) | 21.5 ± 12 | 9 (52.9) | 293.2 ± 59.4 | 1 (5.8) |
| Septic arthritis (n = 17) | 11805 ± 5401 | 9 (52.9) | 55.4 ± 34.9 | 14 (82.3) | 298.1 ± 109.4 | 2 (11.7) |
| Guillain-Barré syndrome (n = 11) | 9390 ± 2659 | 3 (27.2) | 18.1 ± 11 | 2 (18.1) | 323 ± 86.2 | 3 (27.2) |
| Cellulitis (n = 9) | 10233 ± 3440 | 3 (33.3) | 20.2 ± 9.8 | 6 (66.6) | 276.4 ± 76.9 | 0 (0) |
aValues are expressed as No (%) or mean ± SD Abbreviations: CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; WBC, white blood cell.


