Passive Eversion Assessment for Progressive Collapsing Foot Deformity After Lateral Column Lengthening: A Cadaveric Biomechanical Study.

Reduced hindfoot eversion motion has been proposed as a cause of increased lateral foot pressure following lateral column lengthening (LCL) for progressive collapsing foot deformity (PCFD). A subjective intraoperative assessment of passive eversion has been suggested to help evaluate correction; however, it is unclear how passive eversion correlates with objective measurements of foot stiffness. Our objectives were to quantify the relationship between the maximum passive eversion in hindfoot joints following LCL with plantar pressure during stance and to determine the influence of wedge size on these outcomes. Ten cadaveric specimens extending from the mid-tibia distally were tested on a 6-degrees-of-freedom robot to simulate the stance phase of level walking. Five conditions were tested: intact, simulated PCFD, and 3 LCL wedge conditions (4, 6, and 8 mm). Outcomes included the lateral-to-medial forefoot plantar pressure (LM) ratio during stance and the maximum passive eversion measured in the hindfoot joints. Simple linear regressions were performed to evaluate relationships between outcomes and wedge sizes. A strong negative relationship was found between passive subtalar eversion and the LM ratio during stance (r[38] = -0.46; p = 0.0007), but not between passive talonavicular eversion and the LM ratio (r[38] = -0.02; p = 0.37). Wedge size was strongly related to subtalar eversion (r[38] = -0.77; p < 0.0001), talonavicular eversion (r[38] = -0.55; p = 0.0003), and the LM ratio (r[38] = 0.70; p < 0.0001). Increased wedge size resulted in average decreases in subtalar and talonavicular eversion of 1.0° (95% confidence interval [CI]: 0.8° to 1.3°) and 1.2° (95% CI: 0.6° to 1.6°), respectively. Increased wedge size also increased the LM ratio by 0.38 (95% CI: 0.25 to 0.50), indicating a lateral shift in plantar pressure. Decreased hindfoot eversion following LCL was related to increased lateral plantar pressure during stance. Increasing wedge size correlated with decreasing passive hindfoot eversion and increasing lateral plantar pressure, suggesting that intraoperative preservation of eversion motion may be important for preventing excessive lateral loading. To avoid overcorrection or undercorrection of the deformity, hindfoot eversion assessment in addition to radiographic evaluation may be important for optimizing the amount of lengthening to achieve successful LCL.

Kim J ，Hoffman JW ，Ellis SJ ，Deland JT ，Steineman BD ... -  《-》

Consensus for the Indication of Lateral Column Lengthening in the Treatment of Progressive Collapsing Foot Deformity.

Thordarson DB ，Schon LC ，de Cesar Netto C ，Deland JT ，Ellis SJ ，Johnson JE ，Myerson MS ，Sangeorzan BJ ，Hintermann B ... -  《-》

Peroneus Brevis to Longus Tendon Transfer in the Treatment of Flexible Progressive Collapsing Foot Deformity: A Cadaveric Study.

Conti MS ，Kim J ，Hoffman J ，Jones CP ，Ellis SJ ，Deland JT ，Steineman B ... -  《-》

The Foot and Ankle Kinematics of a Simulated Progressive Collapsing Foot Deformity During Stance Phase: A Cadaveric Study.

Henry JK ，Hoffman J ，Kim J ，Steineman B ，Sturnick D ，Demetracopoulos C ，Deland J ，Ellis S ... -  《-》

Effect of graft shape in lateral column lengthening on tarsal bone position and subtalar and talonavicular contact pressure in a cadaveric flatfoot model.

Lateral column lengthening (LCL) has been used for correction of flatfoot deformity. The purpose of this study was to determine the effect of LCL graft shape on tarsal bone position and talonavicular and subtalar joint pressure. A flatfoot model was created in 6 cadaveric specimens. Corrective LCL was performed using a rectangular graft or a trapezoidal graft with the broad surface oriented dorsally, laterally, or plantarly. Bony surface markers were digitized to calculate angular parameters used in the evaluation of flatfoot deformity. Contact pressure and area in the subtalar and talonavicular joints were also recorded. All measurements were carried out under multiple axial loads in the intact and flatfoot conditions, and following LCL with each graft shape. Flatfoot creation resulted in significant changes in arch collapse and forefoot abduction. LCL with a rectangular graft best corrected these parameters, while a laterally oriented trapezoidal graft provided some correction. Talonavicular contact pressure was unchanged after flatfoot creation, and was significantly less than intact after LCL. Subtalar contact pressure decreased in some conditions after flatfoot creation, and decreased further after LCL. LCL with a rectangular graft best restored tarsal bone orientation in a cadaveric flatfoot model. The decreases in talonavicular pressure likely represent redistribution of force from the medial to lateral foot. When performing LCL for flatfoot deformity, increased bone graft volume medially better restores tarsal bone position. One way of achieving this is through the use of a rectangular graft as opposed to a trapezoidal graft.

Campbell ST ，Reese KA ，Ross SD ，McGarry MH ，Leba TB ，Lee TQ ... -  《-》