The patient was initially presented to our clinic at the age of 9 with a chief complaint of limping. Her developmental history was notable for developmental delay without underlying genetic or autoimmune conditions and low infantile weight for which she had a gastric tube. Family history was negative for any neuromuscular disease, hip dysplasia, or autoimmune disease. She had recently moved from Mexico with her family to the United States.
Her initial exam revealed a Trendelenburg gait and sign, left hip pain-free range-of-motion with 100  internal rotation, 50  external rotation, 135  flexion, 20 extension, and 70  abduction. Her right hip revealed pain-free range-of-motion with 90  internal rotation, 50  external rotation, 135  flexion, and 60  abduction. The comparison of both hips revealed a positive Galeazzi sign with a leg-length difference of 2 cm and normal bilateral reflexes. Imaging demonstrated bilateral hip dysplasia with left hip dislocation with pseudoacetabuli (Figures 1 and 2). At this time, the working diagnosis was untreated bilateral hip dysplasia, and we discussed surgical options including fusion, pelvic and femoral osteotomies, and total hip arthroplasty (THA). Given the chronicity of her dislocation and severity of her dysplasia, it was determined that any surgical treatment on the unilateral left hip dislocation was unlikely to provide a significant benefit and may make her worse. We recommended proceeding with a possible THA versus fusion in her teenage years when pain warranted treatment. For the right hip, we recommended a future periacetabular osteotomy (PAO) once her triradiate cartilage closed and her hip became symptomatic, possibly in a few years.
She was unfortunately lost to follow-up and did not receive additional treatment during this time but represented to our clinic 1.5 years later with progressive decrease in ambulation requiring a wheelchair and walker and bilateral left greater than right hip pain. On exam, both hips had painful range-of-motion with the development of a 5  hip flexion contracture on the left and increased flexion, abduction, and internal rotation on the right. Her limp was significantly worse, but her leg-length discrepancy decreased to 0.5 cm. Imaging demonstrated erosive changes of the bilateral femoral heads with infiltrative destructive patterns to the bilateral acetabula, hip effusions, and synovial thickening (Figures 3 and 4). In addition, she developed a new dislocation of the right hip. She was directly admitted from clinic for further work-up. On the day of admission, she had bilateral hip aspirations which showed unremarkable inflammatory fluid changes (left hip: 20 mL of cloudy, turbid, straw-colored fluid, cell count 908, polymorphonuclear cells 2%; right hip: 80 mL of bloody, cloudy fluid, cell count 359, polymorphonuclear cells 49%). Crystal exam, gram stain, and cultures were negative. Synovial fluid cytology demonstrated numerous benign reactive synovial cells without identification of malignant cells.
Given the severity of the destruction, a possible spinal etiology including tumor syrinx resulting in Charcot joint was suspected. Magnetic resonance imaging of the brain and cervical/thoracic/lumbar spine was within normal limits. Other etiologies including bacterial, fungal, and viral infection were considered. Coccidioidomycosis and histoplasmosis titers and Lyme disease antibodies were negative. To evaluate for tuberculosis, a chest X-ray was obtained within normal limit while CT demonstrated a 4 mm nodule in the right middle lobe that was noncalcifying and believed to be postinfectious. AqQuantiFERON-TB gold test was negative. A complete blood count, basic metabolic panel, CRP (0.3 mg/dL), and ESR (7 mm/hr) were within normal limits with the exception of elevated platelets (550). Compliment fixation serum and immunodiffusion serum tests were negative. Autoimmune etiologies were also considered. Extensive serologic testing was performed including dilute Russel's viper venom time, lupus anticoagulant, anti-CCP, anticentromere, antimitochondrial, anti-double-stranded DNA, antinuclear antibody, anti-SSA, SSB antibody panel, rheumatoid factor (RF), and HLA-B27 which were all negative.
Because of the unusual and severe presentation of the disease and the lack of a diagnosis, on hospital day 10, she was taken to the operating room for bilateral hip arthrocentesis and bilateral hip arthroscopy for biopsy of the bone and synovium. A synovial biopsy was obtained to examine the tissue visually and histologically to confirm the diagnosis of an inflammatory arthritis. Intraoperative findings demonstrated right capsular destruction with unusual appearing and inflamed and reddened synovium with erosive destruction of the articular surface of the femoral head and acetabulum. On the left, there was a free-floating femoral head with multiple moderate-sized osteochondral loose bodies grossly inflamed synovium, intact labrum, no clearly discernable joint capsule, and near-complete absence of cartilage within the acetabulum and overlying the femoral head (Figure 5). Following the diagnostic component of the arthroscopy, she underwent a left femoral head arthroscopic resection, bilateral synovial and bone biopsies, and bilateral Kenalog intra-articular injections for pain relief. Biopsy results demonstrated synovial hyperplasia with chronic inflammatory changes. Postoperative X-rays showed left femoral head resection (Figure 6).
Given the results of the arthroscopic findings and synovial biopsy, we subsequently referred the patient to a board-certified pediatric rheumatologist for further evaluation. Additionally, she was found to have moderate arthropathy of her right calcaneocuboid and bilateral 1st metatarsophalangeal joints. Given these clinical findings, she was given the diagnosis of Persistent Oligoarticular JIA characterized by negative RF, CCP, and HLA-B27 and was subsequently started on methotrexate and folic acid.
At 3-year postoperatively, she has continued erosion of the right femoral head (Figure 7). A genetics consult was obtained, and comprehensive screening was negative. She remains nonweight bearing with the plan for bilateral THAs once she becomes a teenager. However, this could result in multiple challenges if the patient becomes nonambulatory, has limited acetabular bone stock, if the hip dysplasia requires femoral shortening, or if custom implants are needed due to the small size and deformity.