Hip reconstruction in closed triradiate cartilage: long-term outcomes in patients with cerebral palsy

Hip reconstruction is an established procedure in pediatric patients with neurogenic hip dislocation. An open triradiate cartilage provides the advantage of a high plasticity of the bone which prevents an intraarticular fracture and postoperative adaptation of shape. Some patients with dislocated hips, however, arrive late. A hip reconstruction is still feasible as shown earlier but the long-term risk for osteoarthritis, and recurrence of dislocation, and functional outcome is unknown. It is the aim of our investigation to evaluate long-term clinical and radiological outcomes of hip reconstruction by Dega type pelvic osteotomy performed after fusion of the triradiate epiphyseal cartilage in patients suffering from cerebral palsy.

We retrospectively analyzed 43 hips in 37 patients with a hip reconstruction for correction of hip dislocation or subluxation. In all patients, the triradiate cartilage was fused before surgery. Age at surgery was 15 years and 2 months on average and follow-up time was mean 13 years 5 months.

Mean Kellgren Lawrence score at final follow-up was significantly higher than at preoperative investigation (P < 0.00001). At long-term follow-up 3 of 43 hips had developed pain, and 1 of them required arthroplasty. Reimers´ migration index was stable over the years and was not higher at last follow-up compared to the index observed shortly after surgery (P = 0.857), so was the Sharp angle (P = 0.962). We found no significant reduction in the range of motion of the hip in the sagittal plane.

We noted mild radiological signs of osteoarthritis which possibly occur due to an intraarticular acetabulum fracture during bending down the acetabulum. Nevertheless, hip reconstruction in patients with cerebral palsy and closed triradiate cartilage remains a valuable option as it results in a stable, painless hip for more than a decade.