Stabilization of the femoral head with a gliding screw in slipped capital femoral epiphysis.

OBJECTIVE

In situ fixation of the proximal femoral epiphysis to prevent further dislocation while maintaining the potential for longitudinal growth by insertion of a central gliding screw. Prevention of secondary coxarthrosis.

INDICATIONS: Incipient and imminent slipped capital femoral epiphysis in children with a displacement angle of < 30 degrees in the axial view (ET' < 30 degrees ) and prophylactic treatment of the contralateral side.

CONTRAINDICATIONS: Allergies to implant materials.

SURGICAL TECHNIQUE: A Kirschner wire is inserted through a lateral proximal approach in the femur into the center of the displaced epiphysis at a right angle to its base. Overdrilling of the wire, thread tapping in the cancellous bone, insertion of the cannulated gliding screw with washer. The screw threads lie only in the epiphysis. The unthreaded part of the screw bridges the growth plate. The screw is allowed to protrude by about 2.5 cm to prevent an epiphyseodesis effect.

POSTOPERATIVE MANAGEMENT: Partial weight bearing of the affected extremity up to 10 kg body weight for 6 weeks. Thrombosis prophylaxis during convalescence only for adolescents with signs of puberty (menarche/pubarche). Restriction on sports activities for 3 months. Follow-ups: clinical and radiologic examinations at 3 months postoperatively, then clinical examination every 6 months and radiologic assessment annually (possibly earlier, if there is a growth spurt). The gliding screw is removed when growth is completed.

RESULTS

63 hips (34 prophylactically and 29 therapeutically) were stabilized with the gliding screw. Clinically, the prophylactically stabilized hips showed excellent outcomes; of the therapeutically stabilized hips, the results were 19 excellent, seven good, two satisfactory, and one poor. Differences in leg length were seen in five cases, whereby the average value was 0.3 cm (0-1 cm). Chondrolysis or femoral head necrosis was not observed. Screw revision was necessary in 22 cases because contact between the screw head and the cortex would have prevented continued longitudinal growth (unintentional epiphyseodesis).