Posteromedial bowing of the tibia: A benign condition or a case for limb reconstruction?

Abstract

PurposeTo review the initial deformity and subsequent remodelling in posteromedial bowing of the tibia and the outcome of limb reconstruction in this condition.Patients and MethodsIn all, 38 patients with posteromedial bowing of the tibia presenting between 2000 and 2016 were identified. Mean follow-up from presentation was 78 months. A total of 17 patients underwent lengthening and deformity correction surgery, whilst three further patients are awaiting lengthening and deformity correction procedures.ResultsThe greatest correction of deformity occurred in the first year of life, but after the age of four years, remodelling was limited. The absolute leg-length discrepancy (LLD) increased throughout growth with a mean 14.3% discrepancy in tibial length. In the lengthening group, mean length gained per episode was 45 mm (35 to 60). Mean duration in frame was 192 days, with a mean healing index of 42.4 days/cm. Significantly higher rates of recurrence in LLD were seen in those undergoing lengthening under the age of ten years (p = 0.046). Four contralateral epiphysiodeses were also performed.ConclusionPosteromedial bowing of the tibia improves spontaneously during the first years of life, but in 20/38 (53%) patients, limb reconstruction was indicated for significant residual deformity and/or worsening LLD. For larger discrepancies and persistent deformity, limb reconstruction with a hexapod external fixator should be considered as part of the treatment options.Level of evidenceLevel IV (Case series)

Deformity progression in congenital posteromedial bowing of the tibia: a report of 44 cases.

“…In other words, the greater is the angular deformity at birth, the wider will be the LLD at skeletal maturity. This finding is confirmed by previous reports [2,3,8,18].…”

“…To the best of our knowledge, this study describes the largest series of children with CPMBT. To date, about 200 cases of CPMBT have been reported in the available literature [1][2][3][4][5]7,8,[14][15][16][17][18]. For years,…”

“…thereafter, the rate of spontaneous correction showed a marked reduction. Other authors reported that, in CPMBT, the greatest rate of correction is observed during the first year of life, and rapidly decreases until the age of four [2][3][4]15,18]. This aspect may have practical implications, because an extreme bowing of tibia in a school-age child might hamper even the possibility of using braces to aid walking.…”

“…In our series, only one patient underwent distal tibial hemiepiphysiodesis to treat ankle valgus. Nonetheless, it is our opinion that, if at age of 10-11 years, the valgus inclination of the distal tibial articular surface persists, a medial distal tibial hemiepiphysiodesis may be performed, when sufficient growth potential is still present [18][19]. This simple procedure can effectively realign the ankle, minimizing the complications [22][23][24][25][26][27] and avoiding demanding realignment procedures (double or triple corticotomies, complex external fixation constructs) at the end of growth.…”

“…Finally, almost a half of cases did not reach the definitive treatment. These issues, were reported in most of the previously published case series describing CPMBT [2][3][4][5]18], emphasizing the difficulty to achieve complete information about ultrarare developmental pathologies, in which at most one case per year can be collected, even in the highly specialized referral institutions. In order to address this issues and minimize biases, we used mixed effect models, a complex statistical approach that allows to maximize the prediction power from small and heterogeneous groups of subjects with missing data; nonetheless, we are aware of potentially biased results as well as a loss of statistical power and precision.…”