Valgus Deformity After Reconstruction of the Anterior Cruciate Ligament in a Skeletally Immature Patient: A Case Report*


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Whether acute or chronic, rupture of the anterior cruciate ligament is uncommon in children, most likely because the strength of the ligament is greater than that of bone or physes in children [3,5]. However, intrasubstance ruptures of the anterior cruciate ligament can occur in young patients [1,2,4,6-8,11-17,19]. A heightened awareness of injuries to the ligament and the fear of irreparable damage to the cartilage and menisci have created a trend toward operative treatment [1,2,4,6-8,11-17,19]. Intra-articular reconstruction of the anterior cruciate ligament has been successful in adults; however, drilling across an open growth plate is a cause of concern because it may lead to the formation of an osseous bridge, resulting in premature physeal closure, limb-length discrepancy, and angulation of the involved extremity [10].We report on a fourteen-year-old boy who was managed with a transphyseal intra-articular reconstruction of the anterior cruciate ligament of the right knee. He subsequently had premature closure of the distal femoral physis that resulted in a valgus deformity of the lower extremity.Case ReportA boy, fourteen years and four months old, sustained an injury of the right knee while playing football. The knee gave way and immediately swelled. The patient was evaluated in an emergency room, and he was referred to an orthopaedic surgeon. Physical examination revealed a large effusion in the right knee, positive Lachman and drawer signs, and a positive pivot-shift test. Knee flexion was limited to 90 degrees. Radiographic examination of the knee revealed no fractures. A rupture of the anterior cruciate ligament was diagnosed at that time. The patient began a rehabilitation program in an attempt to regain a full range of motion of the knee.After one month of rehabilitation, the patient regained a full range of motion but the right knee remained unstable. The physician recommended reconstruction of the anterior cruciate ligament. The hospital chart contained no information regarding the amount of growth remaining, the stage according to the classification system of Tanner [20], the heights of family members, the bone age, or the occurrence of an adolescent growth spurt.An arthroscopically assisted reconstruction of the anterior cruciate ligament with a double-stranded semitendinosus graft was performed. The original anterior cruciate ligament was completely ruptured. There was no evidence of a tear of the medial or lateral meniscus or of areas of cartilage degeneration in the three compartments of the knee. The stump of the ligament was debrided, and a notchplasty was performed. A 45-degree tibial tunnel of unknown diameter and a nine-millimeter endoscopic femoral tunnel were drilled. An Arthrex guide (Naples, Florida) was used to insert the looped double-stranded tendon graft across the tibial and femoral tunnels. The tendon was transfixed with a cannulated screw across the lateral femoral condyle. Cancellous bone plugs were inserted within the tibial and femoral tunnels. The distal part of the tendon was transfixed with two six-millimeter staples at the distal end of the tibial tunnel (Figure 1). After the reconstruction was completed, intraoperative examination of the knee revealed negative Lachman and pivot-shift tests with a firm end point.Two years later, when the patient was sixteen years and three months old, he was first seen at our institution because of a progressive valgus deformity of the involved lower extremity. There was no history of trauma, pain, or instability after the procedure. Physical examination revealed a full range of motion of the knee and a negative pivot-shift test. Lachman and drawer tests demonstrated grade-I laxity with a stable end point. The knee was stable to varus and valgus stress.

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