SLR - September 2013 - Kathie J. Whitt
Reference: Oh I, Imhauser C, Choi D, et al (2013) Sensitivity of Plantar Pressure and Talonavicular Alignment to Lateral Column Lengthening in Flatfoot Reconstruction. J Bone and Joint Surgery, 95(12):1094-100.
Scientific Literature Review
Reviewed by: Kathie J. Whitt, DPM
Residency Program: Grant Medical Center
Podiatric Relevance: Lateral column lengthening (LCL) within the calcaneus is commonly performed in the correction of adult acquired flatfoot deformity. Although LCL offers powerful correction of talonavicular subluxation, postoperative increases in lateral plantar pressure leading to pain, stiffness, and fifth metatarsal stress fractures have been reported. It is therefore essential that LCL be done judiciously, with regard to the effect each two millimeter increase has on angular correction of the talonavicular joint as well as on lateral forefoot pressure.
Methods: Eight fresh-frozen cadaveric foot specimens were included in the study. A robot was used to compressively load the foot to 400 N of axial force while loading the Achilles tendon to 310 N, replicating the midstance phase of walking. A flatfoot model was created by resecting the medial and inferior soft tissues of the midfoot, and increasing the axial load to 800 N for 100 cycles. To compare the different amounts of LCL an osteotomy was made 1.5 cm proximal to the calcaneocubiod joint and stainless steel wedges (six, eight, and 10 mm) were employed. Kinematic and plantar pressure data were gathered for each of the five conditions: intact, flatfoot, six-millimeter LCL, eight-millimeter LCL, and 10-mm LCL.
Results: In the flatfoot condition, talonavicular joint angulation data demonstrated a median abduction angle of 4.4° in the axial plane and −2.6° in the sagittal plane compared with the intact condition. Axial correction of the talonavicular alignment with six, eight, and 10 mm of LCL was respectively −1.4°, −4.9°, and −9.2° beyond that of the intact foot. Sagittal correction of −0.1°, 1.3°, and 2.9°, was also seen. The lateral forefoot average mean pressure, peak pressure, and contact area all consistently increased with each two millimeter increase in LCL.
Conclusions: The LCL procedure is widely used for correction of Stage-IIB adult acquired flatfoot deformity despite the potential complications including nonunion, lateral foot pain, and stress fracture. Due to the variations in flat foot deformity an ideal length cannot be generalized. The results of this study found geometric and plantar pressure parameters were restored most closely to the intact rectus condition when six millimeters of lengthening was used. This suggests that six millimeter LCL is most appropriate for mild to moderate flatfoot deformity. It was also determined that lengthening in the range of six-to-10 mm has the potential to be associated with progressive increase in pressure in the lateral part of the forefoot, leading to potential overload.