Between 1976 and 1988 we treated 75 junior high athletes who had midsubstance ruptures of the anterior cruciate ligament and open physes. Thirty-eight children were initially treated conservatively and later had an intraarticular patellar tendon graft reconstruction, 2 patients underwent extraarticular reconstruction and then later had a patellar tendon graft intraarticular reconstruction, and 20 children had a patellar tendon graft reconstruction initially. In all 60 patients the tibial and femoral tunnels were drilled through the open physes. Minimum followup was 2 years (mean, 4.2). Fifty-five of the 60 children were able to return to their original sports; 5 were active in less strenuous sports. No incidence of abnormal growth related to the intraarticular reconstructive surgery was recorded. Three children tore their anterior cruciate ligament grafts more than 2 years after surgery. Our records showed that conservative treatment of the active junior high athlete with an anterior cruciate ligament rupture failed in each case because of recurrent giving way or meniscal tears. Definitive treatment with an intraarticular autogenous patellar tendon graft reconstruction yielded good to excellent results and eliminated subsequent instability episodes and meniscal tears in our study group.