Current Concepts In Surgery For Adult-Acquired Flatfoot
We typically address hindfoot valgus associated with stage II AAF with a medial transpositional osteotomy of the posterior calcaneus. It has been well established that this osteotomy is effective in reducing hindfoot valgus by redirecting the coronal vector of the Achilles tendon from eversion to inversion.5-7 Although we routinely use a medial transpositional osteotomy of the posterior calcaneus to address hindfoot valgus, we rarely use the osteotomy as an isolated procedure in stage II AAF. While a medial transpositional osteotomy will have a direct effect on the subtalar joint, it has a much lesser effect on the midtarsal joint. Therefore, the majority of deformities in stage II AAF are often too severe to correct by an isolated medial transpositional osteotomy.
Vora and co-workers compared the effectiveness of the medial transpositional osteotomy of the posterior calcaneus in correcting mild versus severe flatfoot.8 They concluded that one might treat less severe AAF by a medial transpositional osteotomy whereas more severe deformities may require an additional procedure.
Bolt and colleagues compared lateral column lengthening and medial transpositional osteotomy of the posterior calcaneus for reconstruction of AAF.9 They found the rate of re-operation was twice as high for medial transpositional osteotomy. This was due to inadequate realignment. Therefore, we routinely use a medial transpositional osteotomy in conjunction with a lateral column lengthening.
What You Should Know About Lateral Column Lengthening
We prefer lateral column lengthening as our primary procedure for most cases of stage II AAF. A lateral column lengthening will reduce inversion demand on the posterior tibial tendon, reduce the Achilles force required to achieve a heel rise position, and adduct and plantarflex the midfoot relative to the hindfoot. Lengthening the lateral column also creates a “bowstringing” effect on the peroneus longus tendon, which might be responsible for clinical restoration of the longitudinal arch.10-12
One can perform a lateral column lengthening through an osteotomy of the anterior calcaneus or an interpositional bone block arthrodesis of the calcaneocuboid joint. Our preference is an anterior calcaneal osteotomy. We performed calcaneocuboid joint bone block arthrodesis from 1996 to 2001 but abandoned this procedure due to a relatively high number of complications. Furthermore, the literature has clearly shown that it is best to perform lateral column lengthening with a calcaneal osteotomy rather than a bone block arthrodesis because of the high complication rate.13-19
Emerging Insights On Fixation And Avoiding Displacement
We have used allograft as our choice of bone graft. Research has shown allograft to be an acceptable form of graft for lateral column lengthening.20-23 In a retrospective analysis of anterior calcaneal osteotomies using allograft bone, Shine and colleagues demonstrated that allograft bone was a safe and effective biomaterial for lateral column lengthening in adults.22