Comparison of bioabsorbable versus metallic implant fixation for physeal and epiphyseal fractures of the distal tibia.

BACKGROUND: Transepiphyseal screw fixation of displaced distal tibial epiphyseal fractures is the most common method of treatment for these intraarticular injuries. Recent literature indicates that retained transepiphyseal metallic screws cause an increase in ankle joint contact pressure, thus favoring screw removal. Our hypothesis is that bioabsorbable screw fixation is an alternative to metallic fixation, which offers similar results without the need for screw removal.

METHODS: This is a retrospective review of distal tibial epiphyseal ankle fractures treated with screw fixation. Two groups, those treated with bioabsorbable screw fixation (group B, n = 24) and those with metallic screw fixation (group M, n = 26), were compared (t test) for differences in clinical and radiographic outcomes.

RESULTS: Analysis of demographic data revealed no significant differences between groups for sex, ethnicity, age, and height. Group B was significantly heavier than group M (67.4 vs 55.6 kg; P = 0.0496). Each group had a similar number of Salter-Harris types III and IV medial malleolus fractures and transitional fracture types. There was no significant difference between groups in the time from injury to fixation or in operative time. Radiographically, there were no nonunions in either group, and at final follow-up, 1 patient in group B had distal tibial joint line irregularity versus 3 in group M. Clinically, there were no significant differences between groups in time to full weight bearing or time to full activities.There were fewer complications in group B. A single case of loss of reduction requiring revision fixation occurred in each group. There was one documented growth arrest in group M and 2 suspected growth arrests in each group. Two patients in group M were successfully treated for a superficial wound infection with oral antibiotics. Fourteen patients in group M underwent planned screw removal.

CONCLUSIONS: Bioabsorbable screw fixation can be used for distal tibial epiphyseal fractures with no increase in operative time, nonunion rate, number of unplanned secondary surgeries, or other complications. The use of bioabsorbable screws eliminates the need for epiphyseal screw removal. A prospective randomized study is planned to eliminate the potential selection bias and to standardize clinical and radiographic follow-up.

LEVEL OF EVIDENCE: Level III, case-control study.