Attempted limb lengthenings beyond twenty percent of the initial bone length: results and complications

In response to historic guidelines suggesting limits to the amount of limb lengthening, we report the results and complications of those patients in whom the initial goal of lengthening exceeded 20% of the initial segment length. Thirty-one patients underwent a total of 35 attempted lengthenings with a mean follow-up of 38.6 months. Limb-length discrepancy was the primary indication in all but one case. With an average goal of 35% of the original bone length, we achieved a mean gain of 33%. Lengthening to within 2.5 cm was achieved in 31 (89%) of 35 cases, and significantly more successful with goals extending < or =55% of the initial bone length (p<0.05). Treatment times extended a mean of 8.7 months with a healing index of 37 days/cm. By Paley's classification scheme, all had problems, in addition to an average of 1.3 obstacles and 0.9 complications per segment lengthened. In 23 patients with extended follow-up, good to excellent results were achieved in 78%, and were significantly more successful with goals < or =55% (< or =0.05).