Twenty-nine total hip arthroplasties in 16 patients with juvenile chronic arthritis were performed by one surgeon and followed prospectively. The 9 female and 7 male patients averaged 21 years of age (range, 14-35). Height and weight averaged 160 cm (63 inches) and 53 kg (118 lb.), respectively. Preoperative planning used small or miniature components to accommodate the small anatomic proportions of the hip. The femoral component was cementless in the majority (20/29), but required cementing in 10 of 29 hips because of poor bone stock. The acetabula were reconstructed with a porous-coated cup with or without screws (27/29) or with a cemented cup (2/29). Follow-up periods averaged 53 months (range, 24-100 months). The average Harris hip score improved from 37 to 78 after surgery (P = .0001). Pain relief was excellent; 15 of 16 patients (27/29 hips) expressed a significant improvement in daily function and lifestyle, despite systemic involvement of their arthritis. The range of motion of the hip improved significantly in all planes (P = .001). Two of the 4 uncemented Muller CDH components (Protek, Bern, Switzerland) with a large offset have migrated into varus; both are pain-free. One cemented femoral component has been revised because of aseptic loosening. The use of a small or miniature, cemented or cementless femoral component and a porous-coated cup appears to provide an excellent method of hip reconstruction for patients with juvenile chronic arthritis and small anatomic proportions; however, a femoral component with too great an offset should be avoided, because this may result in varus migration of the stem.
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