Is Proximal Fibula Epiphysiodesis Necessary When Performing a Proximal Tibial Epiphysiodesis?

BACKGROUND: Controversy exists regarding the need for proximal fibular epiphysiodesis in conjunction with proximal tibial epiphysiodesis to prevent relative overgrowth of the fibula. The purpose of this study was to determine the incidence of relative fibular overgrowth in patients who had undergone proximal tibial epiphysiodesis with or without proximal fibular epiphysiodesis to manage leg-length discrepancy. METHODS: We identified patients who had undergone proximal tibial epiphysiodesis, with or without concomitant fibular epiphysiodesis, followed to skeletal maturity, and with adequate scanograms to measure tibial and fibular lengths. We assessed tibial and fibular lengths, ratios, and distances between the tibia and fibula proximally and distally preoperatively and at skeletal maturity, and obvious radiographic proximal migration of the fibular head. RESULTS: A total of 234 patients met inclusion criteria, including 112 girls and 122 boys. In total, 179 patients had undergone concomitant fibular epiphysiodesis, and 55 had not. The fibular epiphysiodesis group was significantly younger preoperatively than the nonfibular epiphysiodesis group (average: 12.3 vs. 13.6 y), which accounted for most of the preoperative differences noted between the groups. Within the subset of younger patients (≥2 y of growth remaining at the time of epiphysiodesis), there were statistically significant differences between those with or without fibular epiphysiodesis at skeletal maturity in the proximal tibial-fibular distance (P<0.01) and the tibia:fibula ratio (0.96±0.02 vs. 0.98±0.02; P<0.02), but not in the distal tibial-fibular distance (P=0.46). Obvious fibular head proximal migration was noted in 10 patients, including 5/179 with concomitant proximal fibular epiphysiodesis, and 5/55 without (P<0.01). No patient was recorded as symptomatic with radiographic overgrowth, and no peroneal nerve injury occurred in any patient in this cohort. CONCLUSIONS: On the basis of this study, concomitant proximal fibular epiphysiodesis does not appear to be necessary in patients with 2 years or less of growth remaining, nor does it unequivocally prevent fibular head overgrowth. While the tibia:fibula ratio was quite consistent in general, there were individuals with relative fibular head prominence for whom fibular epiphysiodesis may be appropriate, particularly in relatively immature patients. LEVEL OF EVIDENCE: Level III-retrospective comparative study.