Patella re-alignment in children with a modified Grammont technique: Outcome in 65 knees after mean 8 years

BACKGROUND AND PURPOSE: In skeletally immature patients, surgical options due to recurrent patella dislocation are limited, because bony procedures bear the risk of growth disturbances. In this retrospective study, we report the long-term functional and radiographic outcome in skeletally immature patients using the modified Grammont surgical technique. PATIENTS: Between 1999 and 2004, 65 skeletally immature knees (49 children) were treated with a modified Grammont procedure: an open lateral release and a shift of the patella tendon insertion below the growth plate on the tuberositas tibia, allowing the tendon to medialize. At mean 8 (5.6–11) years after surgery, 58 knees in 43 patients were evaluated by clinical examination, from functional scores (Lysholm, Tegner), and from radiographs of the knees. RESULTS: Mean Lysholm score was 82 postoperatively. Tegner score decreased from 6.2 to 5. Eight knees had a single dislocation within 3 months of surgery. 3 knees had repeated late dislocations, all with a high grade of trochlea dysplasia. 6 knees showed mild signs of osteoarthritis. No growth disturbances were observed. INTERPRETATION: The modified Grammont technique in skeletally immature patients allows restoration of the distal patella tendon alignment by dynamic positioning. Long-term results showed that there were no growth disturbances and that there was good functional outcome. However, patients with a high grade of trochlea dysplasia tended to re-dislocate.