2.1. Patients

We reviewed the cases who underwent tibial lengthening with submuscular plating from 2015 to 2019 at our institution. The inclusion criteria were tibial lengthening in patients with knee angular deformity requiring a metaphyseal osteotomy and a minimum of 2 years follow-up. Cases with combined femoral lengthening or a follow-up less than 2 years were excluded. Ten males and nine females were included in this retrospective study. Among 19 patients, 10 received tibial lengthening with knee angular deformity correction using an oscillating saw (Group 1), and nine received tibial lengthening without angular deformity correction using multiple drill holes and an osteotome (Group 2). Among all 10 cases who required knee angular deformity correction, there were varus deformity corrections on four limbs and valgus deformity corrections on six limbs. All cases were performed by the senior author (T.-M. Wang).

The average age at operation was 14.1 years (range, 7–35 years). The average postoperative follow-up period was 55.1 months (range, 28–89 months). The mean preoperative body mass index was 21.1 kg/m² (range, 13.6–32.3 kg/m²). The mean preoperative leg-length discrepancy was 4.4 cm (range, 2.3–7.1 cm). Demographic features of all 19 patients included in Groups 1 and 2 are listed in Table 1. There were no significant differences between groups in parameters including age at operation, follow-up period, gender, operated side, leg-length discrepancy, and body mass index.

Demographic features of the included patients.

The etiologies of the deformity included fibular hemimelia (n = 6), idiopathic leg-length discrepancy (n = 4), sequelae of infection (n = 2), X-linked hypophosphatemic rickets (n = 2), congenital pseudoarthrosis of tibia (n = 2), neglected developmental dysplasia of the hip (n = 1), Ollier disease (n = 1), and neurofibromatosis (n = 1). Among all 19 patients, monolateral fixators (Limb Reconstruction System; Orthofix SRL, Verona, Italy), Ilizarov apparatus (Smith and Nephew, Memphis, TN, USA), and Taylor spatial frames (Smith and Nephew, Memphis, TN, USA) were applied to one, 11, and seven patients, respectively. The patient authorization forms for medical record use and academic research purposes were obtained from the patients or guardians. The study was approved by the Institutional Review Board of National Taiwan University Hospital.