Three-Dimensional Distance Mapping to Identify Safe Zones for Lateral Column Lengthening

BACKGROUND

Evans (E-LCL) and Hintermann LCL (H-LCL) lateral column lengthening osteotomies are standard surgical solutions for flexible, progressive collapsing feet. E-LCL is performed between the anterior and middle facets and endangers specific os calcis subtalar joint (OCST) subtypes without distinct facets. H-LCL is oriented between the posterior and middle facets and should be suitable for all OCSTs. Both osteotomies are associated with increased subtalar osteoarthritis, indicating iatrogenic damage. Distance mapping (DM) enables visualization of the relative distance between 2 articular surfaces represented by color patterns. This study aims to measure the safe zones for LCL using 3-dimensional (3D) models and DM; we hypothesize that it could be measured with high reproducibility.

METHODS

Two raters categorized 200 feet across 134 patients into OCSTs based on the Bruckner classification. Four angles were measured independently. The proximal and distal extents of the posterior safe zone (PSZ) angles were determined for H-LCL osteotomies; similarly, the proximal and distal extents of the anterior safe zone (ASZ) angles were identified for E-LCL osteotomies. Consequently, the surface available for safe osteotomies were calculated. An interclass correlation was used to assess the agreement between the 2 raters. Additionally, analysis of variance and Mann-Whitney U test were used to compare the safe zones between OCSTs.

RESULTS

The mean proximal and distal extents of the PSZ angles were 68 ± 7 and 75 ± 5 degrees from a line parallel to the lateral border of the calcaneus, respectively, and the proximal and distal extent of the ASZ angles were 89 ± 6 and 95 ± 5 degrees, respectively. There were no statistically significant differences between the OCSTs. Two raters measured the angles with good to excellent interrater and intrarater agreement. In 18 cases, we were unable to plan for H-LCL or E-LCL osteotomies.

CONCLUSION

Distance mapping could be used to measure the safe zone, tailor a preoperative plan, and potentially reduce the risk for iatrogenic damage in LCL. 3D models and DM can increase the reliability of preoperative plans in bones with complex 3D structures.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Radiographic Outcomes of Titanium Augment vs Bone Graft in Lateral Column Lengthening for Adult-Acquired Flatfoot Deformity

Background

Lateral column lengthening (LCL) is a surgical procedure used to manage forefoot abduction and, in theory, also increases the longitudinal arch by plantarflexion of the first ray through tensioning the peroneus longus for patients with stage IIB adult acquired flatfoot deformity (AAFD). This procedure utilizes an opening wedge osteotomy of the calcaneus, which is then filled with autograft, allograft, or a porous metal wedge. The primary aim of this study was to compare the radiographic outcomes of these different bone substitutes following LCL for stage IIB AAFD.

Methods

We conducted a retrospective review of all patients who underwent LCL from October 2008 until October 2018. Preoperative weightbearing radiographs, initial postoperative radiographs, and 1-year weightbearing radiographs were reviewed. The following radiographic measurements were recorded: incongruency angle, talonavicular coverage angle (TNCA), talar-first metatarsal angle (T-1MT), and calcaneal pitch.

Results

A total of 44 patients were included in our study. The mean age of the cohort was 54 (range, 18-74). The study cohort was divided into 2 groups. There were 17 (38.7%) patients who received a titanium metal wedge and 27 (61.5%) that received autograft or allograft. Patients that underwent LCL with the autograft/allograft group were significantly older (59 vs 47 years old, P = .006). Patients who underwent LCL with a titanium wedge had a significantly higher preoperative talonavicular angle (32 vs 27 degrees, P = .013). There were no significant differences in postoperative TNCA, incongruency angle, or calcaneal pitch at 6 months or 1 year.

Conclusion

At 6 months and 1 year, no radiographic differences were found between autograft/allograft bone substitutes vs titanium wedge in LCL.

Level of Evidence

Level III, retrospective cohort study.

Medium- to Long-term Results of Nonanatomic Spring Ligament Reconstruction Using an Allograft Tendon in Progressive Collapsing Foot Deformity With Severe Abduction Deformity

BACKGROUND

Spring ligament reconstruction (SLR) has been suggested as an adjunct to other reconstructive procedures to potentially avoid talonavicular joint fusion in progressive collapsing foot deformity (PCFD) with severe abduction deformity. Most clinical reports present short-term follow-up data and a small number of patients. The purpose of this study was to examine the medium- to long-term outcomes of an SLR using allograft tendon augmentation as part of PCFD surgical reconstruction. This study to our knowledge represents the largest number of patients and the longest follow-up to date.

METHODS

This study retrospectively reviewed 26 patients (27 feet, mean age of 61.4 years) who underwent SLR with allograft tendon as part of PCFD reconstruction. The mean follow-up of the cohort was 8 years (range, 5-13.4). Radiographic evaluation consisted of 5 parameters including talonavicular coverage angle (TNC), with the maintenance of correction being evaluated by comparing parameters from the early postoperative period (mean: 11.6 months, range, 8-17) to final follow-up. Foot and Ankle Outcome Score (FAOS) and patient satisfaction questionnaires were collected at final follow-up. Conversion to talonavicular or subtalar fusion was considered as a failure.

RESULTS

Final radiographs demonstrated successful abduction correction, with the mean TNC improving from 43.7 degrees preoperatively to 14.1 degrees postoperatively (P < .0001). All other radiographic parameters improved significantly and exhibited maintenance of the correction. All FAOS subscales showed significant improvement. Responses to the satisfaction questionnaire were received from all except 1 patient, of whom 88.5% (23/26) were satisfied with the results, 96.2% (25/26) would undergo the surgery again, and 88.5% (23/26) would recommend the surgery. Eight feet (29.6%) required painful hardware removal and 1 (3.7%) developed nonunion of the lateral column lengthening osteotomy. No patient required conversion to talonavicular or subtalar fusion.

CONCLUSION

This study demonstrates favorable medium- to long-term outcomes following PCFD reconstruction including an SLR with allograft tendon augmentation.

LEVEL OF EVIDENCE

Level IV, case series.

Axial Plane Rotation of the Talus in Progressive Collapsing Foot Deformity: A Weightbearing Computed Tomography Analysis

BACKGROUND

Progressive collapsing foot deformity (PCFD) is recognized as a 3-dimensional deformity centered around the talus. Previous studies have described some features of talar motion in the ankle mortise in PCFD, such as sagging in the sagittal plane or valgus tilt in the coronal plane. However, axial plane alignment of the talus in the ankle mortise in PCFD has not been investigated extensively. The purpose of this study was to examine this axial plane alignment of PCFD vs controls using weightbearing computed tomography (WBCT) images and to determine if talar rotation in the axial plane is associated with increased abduction deformity, as well as to assess the medial ankle joint space narrowing in PCFD that may be associated with axial plane talar rotation.

METHODS

Multiplanar reconstructed WBCT images of 79 patients with PCFD and 35 control patients (39 scans) were retrospectively analyzed. The PCFD group was divided into 2 subgroups depending on preoperative talonavicular coverage angle (TNC): moderate abduction (TNC 20-40 degrees, n=57) and severe abduction (TNC >40 degrees, n=22). Using the transmalleolar (TM) axis as a reference, the axial alignment of the talus (TM-Tal), calcaneus (TM-Calc), and second metatarsal (TM-2MT) were calculated. Difference between TM-Tal and TM-Calc was calculated to examine talocalcaneal subluxation. A second method to assess talar rotation within the mortise utilized an angle between the lateral malleolus and the talus (LM-Tal) in the axial slices of WBCT. In addition, the prevalence of medial tibiotalar joint space narrowing was assessed. These parameters were compared between the control and PCFD groups, and between moderate and severe abduction groups.

RESULTS

The talus was significantly more internally rotated with respect to the ankle TM axis and the lateral malleolus in PCFD patients compared to controls, and in the severe abduction group compared with the moderate abduction group, using both measurement methods. Axial calcaneal orientation did not differ between groups. There was significantly greater axial talocalcaneal subluxation in the PCFD group, and this was also greater in the severe abduction group. The prevalence of medial joint space narrowing was higher in PCFD patients.

CONCLUSION

Our findings suggest that talar malrotation in the axial plane should be considered an underlying feature of abduction deformity in PCFD. The malrotation occurs in both the talonavicular and ankle joints. This rotational deformity should be corrected at the time of reconstructive surgery, especially in cases of severe abduction deformity. In addition, medial ankle joint narrowing was observed in PCFD patients, with a higher prevalence of medial ankle joint narrowing in those with severe abduction.

LEVEL OF EVIDENCE

Level III, case-control study.

How Does Lateral Column Lengthening Improve the Medial Longitudinal Arch? Now I Started to Understand!

Category:

Hindfoot; Other

Introduction/Purpose:

Since its description by Evan for correction of overcorrected clubfoot cases, lateral column lengthening (LCL) has been widely used for correction of pes planovalgus deformity of any etiology, including flexible flat foot deformity in adolescents and adults, either as a solitary procedure or in combination with other bony or soft tissue procedures. The main indication is correction of forefoot abduction manifested radiologically as talonavicular uncoverage. Different techniques were described including Evan and Hintermann techniques. It was reported by many authors that LCL improved forefoot abduction and talonavicular uncoverage, but it was also noticed that LCL corrects the flattening of medial longitudinal arch. The mechanism by which LCL corrects the medial longitudinal arch is still not clearly understood. It was also reported that LCL is associated with forefoot supination, but the exact mechanism of supination is not understood. This study aimed to try to understand the mechanism by which LCL changes the shape of the foot.

Methods:

LCL osteotomy using Hintermann technique was performed in ten fresh frozen below knee cadaveric specimens. After completion of the osteotomy, the talus and leg were removed to monitor how the foot moves under the talus with opening of the osteotomy to change the shape of the foot. After that, the whole plantar skin was removed and plantar ligaments were dissected to study the influence of plantar ligaments on the plane of motion of the osteotomy and the effect of the osteotomy on plantar ligaments.

Results:

With opening of the osteotomy, the distal portion of the foot did not move in pure adduction as might be expected. Instead, it moved medial and plantar, and the osteotomy worked as a dorsolateral opening wedge osteotomy meaning that the osteotomy opened laterally but not medially, and dorsally but not inferiorly. The result was that the distal portion was adducted and plantar flexed, so it can correct the forefoot abduction and the flat arch. Because the osteotomy opens dorsally and laterally only, with no opening medially or inferiorly, the lateral part of the distal portion was plantar flexed more than the medial part, and this is the cause of forefoot supination. After dissection of the plantar ligaments to understand their influence on the osteotomy, it was found that the long and short plantar ligaments prevent the osteotomy from opening inferiorly and force it to work as a dorsolateral opening wedge. It was possible to move the distal portion in pure adduction only after cutting the long and short plantar ligaments. As the osteotomy worked as a dorsolateral opening wedge, the plantar fascia which is plantar and medial was relaxed after opening of the osteotomy.

Conclusion:

May be this can explain how the LCL osteotomy corrects the flat medial longitudinal arch and how it causes supination and lateral side overload. Based on this study, Cotton osteotomy may be needed to be added to LCL to correct the supination. Also, plantar fascia tightening cannot be the cause of medial longitudinal arch correction as it actually becomes more lax after opening of the osteotomy

Radiographic Analysis of the Lateral Column Lengthening Procedure in Stage II Adult Acquired Flatfoot Deformity

Adult acquired flat foot deformity (AAFD) is a progressive, tri-planar deformity involving collapse of the medial longitudinal arch, valgus deformity of the rear foot, and abduction of the mid-foot on the rear foot. There are a wide variety of surgical treatment options for this deformity, including lateral column lengthening (LCL) which results in tri-planar correction of AAFD. We retrospectively reviewed weightbearing preoperative radiographs and weight-bearing 6-week postoperative radiographs of 34 patients with stage II AAFD who underwent LCL (with and without concurrent procedures) with a minimum of 1-year of follow up. Outcomes, including complications and postoperative differences in 6 types of angle measurements were evaluated. Radiographic evaluation showed statistically significant differences in preoperative and postoperative measures in the following angles: calcaneal inclination, Meary's, Simmons, talocalcaneal, and metatarsus adductus (each p ≤ .05). Postoperative Engel's angle difference did not reach statistical significance (p = .07). Paired t tests showed TN coverage angles increased greater with LCL plus a Cotton osteotomy as compared to isolated LCL. Additionally, there was no significant difference in TN coverage angle based on LCL graft size (p = .20). Furthermore, the distance of the osteotomy from the calcaneocuboid joint on anteroposterior and lateral radiographs did not significantly predict TN coverage angle change. Our study suggests that LCL corrects AAFD in three planes while decreasing the metatarsus adductus angle. LCL appears to be more effective when performed with a Cotton osteotomy. Wedge size (6 mm, 8 mm, 10 mm) and osteotomy location did not demonstrate a relationship with postoperative TN coverage angle or incidence of lateral column overload.

Opening Cuboid Wedge Osteotomy (Zoom Osteotomy) for Triplanar Correction of Flexible Pes Planovalgus Deformities

Surgical correction of flexible pes planovalgus often involves reestablishing the length of the lateral column. This is a review of a cohort of patients who underwent an opening cuboid osteotomy with interpositional graft for triplanar correction of flexible pes planovalgus. The medical records of 35 patients involving 51 feet were reviewed. All patients were treated with an opening wedge osteotomy of the cuboid in combination with adjunctive procedures as needed for correction of the pes planovalgus deformity. Radiographs were obtained before and a minimum of 12 months after surgery. Preoperative and postoperative cuboid abduction and Meary's (lateral talometatarsal) angles were measured using the radiographs, and adjunctive procedures and complications were recorded. Mean follow-up was 46 (range, 12-85) months. The mean cuboid abduction angle improved from 20.3° (range, 8°-31°) to 6.6° (range, 0°-15°), and the mean Meary's angle improved from 10.5° (range, 0°-25°) to 2° (range, -3° to 15°). All patients also underwent adjunctive procedures at the time of cuboid osteotomy. In the 51 feet treated, there were 3 (6%) complications, including wound dehiscence, neuritis, and deep vein thrombosis. There were no recurrences. Triplanar correction of flexible pes planovalgus can be performed safely and successfully with an opening cuboid osteotomy as an alternative to the Evans Osteotomy.

Functional Activity After Flatfoot Reconstruction With Lateral Column Lengthening

BACKGROUND

The objective of this study was to evaluate return to activity following flatfoot reconstruction with lateral column lengthening (LCL) by assessing functional postoperative data and identifying patient characteristics associated with poor function following surgery.

METHODS

Consecutive patients that underwent operative flatfoot correction including LCL and other necessary procedures from 2014 to 2019 by 3 fellowship trained foot and ankle orthopedic surgeons were retrospectively administered Foot and Ankle Ability Measure (FAAM) Activities of Daily Living (ADL) and FAAM Sports questionnaires with no preoperative scoring available. Patient demographic factors, comorbidities, and radiographic features were evaluated as predictors of outcome scores to simulate return to activity. Statistical analysis, including student's t-tests and analysis of variance, was performed.

RESULTS

A total of 54 patients were included. A body mass index (BMI) of 30 kg/m2 or greater was associated with a lower ADL score (P = .002) and Sports score (P = .002). Preoperative hindfoot valgus of 9° or higher was associated with higher ADL scores (P = .040). Neither age nor any flatfoot radiographic parameters yielded significant differences in functional scores.

CONCLUSION

This study demonstrated relatively high average FAAM scores in both the ADL and the sports subscales, consistent with previous studies. This study also identified lower BMI and greater preoperative hindfoot valgus as potential predictors of improved functional outcome following reconstruction.

LEVEL OF EVIDENCE

Level III: Retrospective case control.

The Effect of Progressive Lateral Column Lengthening in a Novel Stage II-B Flatfoot Cadaveric Model Evaluated Using Software-Guided Radiographic Measurements of Foot Alignment

BACKGROUND

This work used software-guided radiographic measurement to assess the effects of progressive lateral column lengthening (LCL) on restoring alignment in a novel cadaveric model of stage II-B flatfoot deformity.

METHODS

A stage II-B flatfoot was created in 8 cadaveric specimens by transecting the spring ligament complex, anterior deltoid, and interosseous talocalcaneal and cervical ligaments. Weightbearing computed tomographic (WBCT) scans were performed with specimens under 450 N of compressive load in the intact, flat, and 6-, 8-, and 10-mm lateral column-lengthening conditions. Custom software-guided radiographic measurements of the lateral talo-first metatarsal (Meary) angle, anteroposterior talo-first metatarsal angle, naviculocuneiform overlap, and 2 new measures (plantar fascia [PF] distance and angle) were recorded on digitally reconstructed radiographs. Four anonymized analysts performed measurements twice. Intra- and interobserver agreement was assessed using intraclass correlation coefficients (ICCs).

RESULTS

Six-millimeter LCL restored alignment closest to the intact foot in this new cadaveric model, whereas 10-mm lengthening tended toward overcorrection. The PF line displaced laterally in the flatfoot condition, and LCL restored the PF line to a location beneath the talonavicular joint. Interobserver agreement was excellent for PF distance (ICC = 0.99) and naviculocuboid overlap (ICC = 0.91), good for Meary angle (ICC = 0.81) and PF angle (ICC = 0.69), and acceptable for the talonavicular coverage angle (ICC = 0.65).

CONCLUSION

In this stage II-B cadaveric flatfoot model, cervical ligament transection was essential to create deformity after the medial hindfoot ligaments were transected. Software-guided radiographic measurement proved reliable; standardized implementation should improve comparability between studies of flatfoot deformity. The novel PF distance performed most consistently (ICC = 0.99) and warrants further study. With this model, we found that a 6-mm LCL restored alignment closest to the intact foot, whereas 10-mm lengthening tended toward overcorrection.

CLINICAL RELEVANCE

Future joint-sparing flatfoot corrections may consider using a relatively small LCL combined with other bony and/or anatomic ligament/tendon reconstructions.

Osteoarthritis of the Fourth and Fifth Tarsometatarsal Joint After Calcaneo-Cuboid Distraction Arthrodesis in Flatfoot Correction

Lateral column lengthening procedures are typically performed in patients with flatfoot deformity. There have been reports of complications caused by lateral column lengthening. In this study, clinical and radiographic osteoarthritis of the fourth and fifth tarsometatarsal joints were retrospectively assessed as complications after lateral column lengthening. Seventeen stage II flatfeet belonging to 15 patients were included. The mean age of the subjects was 64.2 ± 7.7 (range 52-80) years. The average lateral column lengthening length achieved was 12.7 ± 2.2 (range 8-15) mm. The average duration of follow-up postsurgically was 57.2 ± 37.7 (range 4-110) months. The pain group (n = 8), who postoperatively experienced weightbearing pain in the plantar-lateral aspect of the foot and/or tenderness at the dorsal-lateral, and the no-pain group (n = 9) were compared. All patients in the pain group underwent lateral column lengthening of 10 mm or more. However, there were no significant differences in age, body mass index, American Orthopaedic Foot and Ankle Society score, and the lateral column lengthening amounts between the groups. In the pain group, all patients had osteoarthritic changes in the fourth and fifth tarsometatarsal joints. In all subjects, 11 feet were diagnosed osteoarthritis. Patients with pain had a significantly lower postoperative first talometatarsal angle (p ≤ .05). Osteoarthritis of the fourth and fifth tarsometatarsal joints as complications after lateral column lengthening in flatfoot is first reported. Our study indicated a high possibility of osteoarthritis in patients who had pain in the lateral aspect of the foot after lateral column lengthening.

A Modified Extra-articular Lateral Column Lengthening Procedure for Adult Acquired Flatfoot Deformity

BACKGROUND

Lateral column lengthening (LCL), originally described by Evans, is an established procedure to correct stage II adult acquired flatfoot deformity (AAFD). However, the relative position between the facets is violated, and other problems may include nonunion, malunion, and calcaneocuboid (CC) joint subluxation. Herein, we report a modified extra-articular technique of LCL with hockey-stick osteotomy, which preserves the subtalar joint as a whole, increases bony apposition to enhance healing ability, and preserves the insertion of the calcaneofibular ligament to stabilize the posterior fragment to promote adduction of the forefoot.

METHODS

We retrospectively recruited 24 patients (26 feet) with stage II AAFD who underwent extra-articular LCL. The mean age was 55.7 ± 15.7 years, and the mean follow-up period was 33.4 ± 12.1 months. Associated procedures of spring ligament repair/reconstruction and posterior tibial tendon plication or flexor digitorum longus transfer were routinely performed and may also include a Cotton osteotomy, heel cord lengthening, or hallux valgus correction. Clinical and radiographic outcomes at the final follow-up were compared with the preoperative assessments.

RESULTS

All patients achieved calcaneus union within 3 months of operation. The VAS pain score improved from 5.3 ± 0.75 preoperatively to 1.2 ± 0.79 at the final follow-up (P < .001), and the AOFAS Ankle-Hindfoot Scale from 63.5 ± 8.5 to 85.8 ± 4.8 points (P < .001). The radiographic measurements significantly improved in terms of the preoperative vs final angles of 8.9 ± 5.3 vs 15.2 ± 3.6 degrees for calcaneal pitch (P < .001), 20.5 ± 9.2 vs 4.9 ± 4.8 degrees for Meary angle (P < .001), 46.5 ± 5.2 vs 41.9 ± 3.2 degrees for lateral talocalcaneal angle (P < .001), 23.9 ± 8.5 vs 3.9 ± 3.1 degrees for talonavicular coverage angle (P < .001), and 18.2 ± 9.2 vs 7.3 ± 5.0 degrees for talus-first metatarsal angle (P = .002). The CC joint subluxation percentage was 7.0% ± 5.4% preoperatively compared with 8.5% ± 2.4% at the final follow-up (P = .101). No case showed progression of CC joint arthritis or CC joint subluxation (>15% CC joint subluxation percentage). One case showed transient sural nerve territory paresthesia, and 1 had pin tract infection. Three cases had lateral foot pain, which could be relieved by custom insoles.

CONCLUSION

Modified extra-articular LCL as part of AAFD correction is a feasible alternative technique without subtalar joint invasion and may be associated with less CC joint subluxation compared with the Evans osteotomy.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Biomechanical Effects of Graft Shape for the Evans Lateral Column Lengthening Procedure: A Patient-Specific Finite Element Investigation

BACKGROUND

The Evans calcaneal lengthening osteotomy procedure is widely used for correcting progressive collapsing foot deformity. However, it can result in overcorrection and degenerations of the calcaneocuboid joint. Different shapes of graft have been used in the Evans calcaneal osteotomy, but potential differences in their biomechanical effects is still unclear. The present study was designed to explore the biomechanical effects of graft shape and improve the Evans procedure to avoid or minimize detrimental effects.

METHODS

Twelve patient-specific finite element models were established and validated. A triangular or rectangular wedge of varying size was inserted at the lateral edge of calcaneus, and the degree of correction was quantified. The stress in spring ligaments and plantar fascia and the contact characteristics of the talonavicular and calcaneocuboid joints were calculated and compared accordingly.

RESULTS

The rectangular graft provided a much higher degree of correction than triangular grafts did. However, the contact characteristics of the calcaneocuboid joint and talonavicular joint were abnormal, with clear sensitivity to increased graft size, and the modeled strain of the spring ligament increased.

CONCLUSION

The finite element analysis predicts that the rectangular grafts provide a higher degree of correction, but risks overcorrection compared with triangular grafts. The triangular graft may have a lower degree of disturbance to the biomechanical behaviors of the midtarsal joint.

CLINICAL RELEVANCE

The model shows that both the shape and size of an Evans osteotomy bone wedge can have effects on the contiguous joints and ligamentous structures. Those effects should be considered when selecting a bone wedge for an Evans calcaneal osteotomy.

LEVEL OF EVIDENCE

Level III, case-control study.

Effect of Lateral Column Lengthening on Subtalar Motion in a Cadaveric Model

BACKGROUND

Although lengthening of the lateral column through a calcaneal neck osteotomy is an integral component of flatfoot reconstruction in younger patients with flexible planovalgus deformities, concern exists as to the effect of this intra-articular osteotomy on subtalar motion. The purpose of this study was to quantify the alterations in subtalar motion following lateral column lengthening (LCL).

METHODS

The subtalar motion of 14 fresh-frozen cadaveric feet was assessed using a 3-dimensional motion capture system and materials testing system (MTS). Following potting of the tibia and calcaneus, optic markers were placed into the tibia, calcaneus, and talus. The MTS was used to apply a rotational force across the subtalar joint to a torque of 5 Nm. Abduction/adduction, supination/pronation, and plantarflexion/dorsiflexion about the talus were recorded. Specimens then underwent LCL via a calcaneal neck osteotomy, which was maintained with a 12-mm porous titanium wedge. Repeat subtalar motion analysis was performed and compared to pre-LCL motion using a paired t test.

RESULTS

No statistically significant differences in subtalar abduction/adduction (10.9 vs 11.8 degrees, P = .48), supination/pronation (3.5 vs 2.7 degrees, P = .31), or plantarflexion/dorsiflexion (1.6 vs 1.0 degrees, P = .10) were identified following LCL.

CONCLUSION

No significant changes in subtalar motion were observed following lateral column lengthening in this biomechanical cadaveric study.

CLINICAL RELEVANCE

Although these findings do not obviate concerns of clinical subtalar stiffness following lateral column lengthening for planovalgus deformity correction, they suggest that diminished postoperative subtalar motion, when it occurs, may be due to soft tissue scarring rather than alterations of joint anatomy.

Anatomical Study of the Cuboid and Its Ligamentous Attachments and Its Implications for a Cuboid Osteotomy

Background:

Lateral column lengthening (LCL) for flexible flatfoot is an effective surgery with powerful correction of deformity because it tightens only the lateral third of the long plantar ligament (LPL). However, LCL has been associated with joint damage at the osteotomy site and loss of foot flexibility owing to joint fixation. We focused on the cuboid and investigate a novel anatomical LCL osteotomy site that effectively tightens the LPL without damaging any joints.

Methods:

We studied 24 feet of 12 cadavers (mean age, 80.8 years). The lengths of the LPL and short plantar ligament, locations of the attachments, and shape and location of the cuneocuboid joint on the medial side of the cuboid were studied. ImageJ software was used to measure the osteotomy angle.

Results:

The lateral cuboid attachment of the LPL on average was located 4.6 mm from the calcaneocuboid joint, and the cuneocuboid joint on average was located 6.7 mm from the cuboid-metatarsal joint on the medial surface of the cuboid. The direct line connecting the anterior cuneocuboid joint and the oblique crest of the cuboid on average was at a 10.3-degree inclination posterior to the cuboid-metatarsal joint.

Conclusion:

A straight line must be selected between a point 4 mm from the calcaneocuboid joint laterally and 6 mm from the cuboid-metatarsal joint medially at a 10-degree posterior tilt to the cuboid-metatarsal joint to perform a cuboid osteotomy LCL without damaging the articular surface.

Clinical Relevance:

We investigated a potential novel cuboid osteotomy method for LCL.

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

RECOMMENDATION

Progressive collapsing foot deformity (PCFD) is a complex 3D deformity with varying degrees of hindfoot valgus, forefoot abduction, and midfoot supination. Although a medial displacement calcaneal osteotomy can correct heel valgus, it has far less ability to correct forefoot abduction. More severe forefoot abduction, most frequently measured preoperatively by assessing talonavicular coverage on an anteroposterior (AP) weightbearing conventional radiographic view of the foot, can be more effectively corrected with a lateral column lengthening procedure than by other osteotomies in the foot. Care must be taken intraoperatively to not overcorrect the deformity by restricting passive eversion of the subtalar joint or causing adduction at the talonavicular joint on simulated AP weightbearing fluoroscopic imaging. Overcorrection can lead to lateral column overload with persistent lateral midfoot pain. The typical amount of lengthening of the lateral column is between 5 and 10 mm.

LEVEL OF EVIDENCE

Level V, consensus, expert opinion.

CONSENSUS STATEMENT ONE

Lateral column lengthening (LCL) procedure is recommended when the amount of talonavicular joint uncoverage is above 40%. The amount of lengthening needed in the lateral column should be judged intraoperatively by the amount of correction of the uncoverage and by adequate residual passive eversion range of motion of the subtalar joint.Delegate vote: agree, 78% (7/9); disagree, 11% (1/9); abstain, 11% (1/9).(Strong consensus).

CONSENSUS STATEMENT TWO

When titrating the amount of correction of abduction deformity intraoperatively, the presence of adduction at the talonavicular joint on simulated weightbearing fluoroscopic imaging is an important sign of hypercorrection and higher risk for lateral column overload.Delegate vote: agree, 100% (9/9); disagree, 0%; abstain, 0%.(Unanimous, strongest consensus).

CONSENSUS STATEMENT THREE

The typical range for performing a lateral column lengthening is between 5 and 10 mm to achieve an adequate amount of talonavicular coverage.Delegate vote: agree, 100% (9/9); disagree, 0%; abstain, 0%.(Unanimous, strongest consensus).

Outcomes of Evans Versus Hintermann Calcaneal Lengthening Osteotomy for Flexible Flatfoot

BACKGROUND

Evans (E) and Hintermann (H) lateral lengthening calcaneal osteotomies (LLCOTs) are commonly used to correct flexible flatfoot deformities. Both methods are well accepted and produce good clinical results. The aim of this study was to compare the postoperative outcomes of both osteotomies.

METHODS

We retrospectively examined 53 patients with flatfoot deformities, who received surgery between October 2008 and March 2014. Seventeen E-LLCOT and 36 H-LLCOT procedures were performed during this time period, with a mean follow-up of 67.7 ± 20.6 and 40 ± 12.9 months, respectively. Data were collected using clinical and radiological examination, as well as clinical scores (Foot and Ankle Outcome Score [FAOS], University of California at Los Angeles [UCLA] activity score, numerical rating scale [NRS], and the Short-Form 36-item Health Survey [SF-36]) during regular follow-up.

RESULTS

For both groups of patients, the FAOS score, pain-NRS, and SF-36 improved significantly following surgery ( P < .05). The talus-second metatarsal angle, talonavicular coverage, and naviculocuneiform overlap showed significant correction ( P < .05). Postoperatively, radiographic degenerative changes were detected in the calcaneocuboid (CC) and subtalar joint in both groups of patients: 41% and 18% after E-LLCOT compared with 25% and 14% after H-LLCOT, although these changes did not have any clinical relevance ( P < .05). No secondary arthrodesis was necessary. There were no significant differences in the clinical or radiological outcome parameters when compared between the 2 groups.

CONCLUSION

Both surgical techniques resulted in a significant improvement of clinical outcome scores and led to good radiological correction of flatfoot deformities. It appears that the CC joint develops less degenerative changes following the H-LLCOT procedure.

LEVEL OF EVIDENCE

Level III, comparative series.

Long-Term Outcomes of Corrective Osteotomies Using Porous Titanium Wedges for Flexible Flatfoot Deformity Correction

Common corrective osteotomies used in flexible flatfoot deformity reconstruction include Cotton and Evans osteotomies, which require structural graft to maintain correction. Auto-, allo-, and xenografts are associated with a number of limitations, including disease transmission, rejection, donor site morbidity, technical challenges related to graft fashioning, and graft resorption. Porous titanium is a synthetic substance designed to address these flaws; however, few studies have been reported on the efficacy, safety, and long-term outcomes. A multicenter retrospective cohort of 63 consecutive preconfigured porous titanium wedges (PTWs) used in flexible flatfoot reconstructions from June 1, 2009 to June 30, 2015 was evaluated. The primary outcome measure was the pre- to postdeformity correction efficacy. The secondary outcomes included maintenance of correction at a minimum follow-up point of 12 months, complications, graft incorporation, and graft safety profile. Multivariate linear regression found a statistically significant improvement in all radiographic parameters from preoperatively to the final weightbearing radiographs (calcaneocuboid 18.850 ± 4.020 SE, p < .0001; Kite's, 7.810 ± 3.660 SE, p = .04; Meary's 13.910 ± 3.100 SE, p = .0001; calcaneal inclination, 5.550 ± 2.140 SE, p = .015). When restricted to patients with >4 years of follow-up data, maintenance of correction appeared robust in all 4 measurements, demonstrating a lack of bone or graft resorption. No patients were lost to follow-up, no major complications or implant explantation or migration occurred, and all implants were incorporated. Minor complications included hardware pain from plates over grafts (8%), 1 case of scar neuritis, and a 5% table incidence of transfer pain associated with the PTWs. These results support the use of PTWs for safety and degree and maintenance of correction in flatfoot reconstruction.

Comparison of Anatomic Structures at Risk With 2 Lateral Lengthening Calcaneal Osteotomies

BACKGROUND:

Lateral lengthening calcaneal osteotomies (LLCOT) are commonly used to treat flexible pes planovalgus deformity. Different operative techniques have been described. The aim of this study was to examine which anatomic structures were affected by 2 different osteotomy techniques.

METHODS:

Two experienced foot and ankle surgeons each performed an Evans (E)- or Hintermann (H) osteotomy on 7 cadaver feet. The mean age of the donors was 80.4 ± 4.4 years. Eight left and 6 right feet were prepared. Previously identified structures at risk were prepared and evaluated.

RESULTS:

After H-LLCOT, there was no damage of the peroneus longus tendon, whereas after E-LLCOT, damage was noted in 1 case (14.3%). The peroneus brevis tendon was once cut after H-LLCOT and eroded after E-LLCOT. In one cadaver, the sural nerve was partially damaged after H-LLCOT but in no case after E-LLOCT. The calcaneal anterior and medial articular facets were intact after H-LLCOT in 100% and 85.7% and after E-LLCOT in 42.9% and 71.4%, respectively. The posterior articular surface was not affected in any cadaver.

CONCLUSION:

Anatomic structures can be damaged after both osteotomies. With the Hintermann osteotomy, the calcaneal anterior and medial articular surface can be protected to a larger extent than with the Evans osteotomy.

CLINICAL RELEVANCE:

The Hintermann osteotomy seems to be superior, regarding damage of the articular surfaces of the subtalar joint. These findings have to be correlated with biomechanical and clinical studies before a final recommendation can be given, which osteotomy is superior.

Porous Titanium Wedges in Lateral Column Lengthening for Adult-Acquired Flatfoot Deformity

Lateral column lengthening (LCL) is a common procedure for reconstruction of stage II flexible adult-acquired flatfoot deformity (AAFD). The recent development of porous titanium wedges for this procedure provides an alternative to allograft and autograft. The purpose of this study was to report radiographic and clinical outcomes achieved with porous titanium wedges in LCL. A retrospective analysis of 34 feet in 30 patients with AAFD that received porous titanium wedges for LCL from January 2011 to October 2014. Deformity correction was assessed using both radiographic and clinical parameters. Radiographic correction was assessed using the lateral talo-first metatarsal angle, the talonavicular uncoverage percentage, and the first metatarsocuneiform height. The hindfoot valgus angle was measured. Patients were followed from a minimum of 6 months up to 4 years (mean 16.1 months). Postoperative radiographs demonstrated significant correction in all 3 radiographic criteria and the hindfoot valgus angle. We had no cases of nonunion, no wedge migration, and no wedges have been removed to date. The most common complication was calcaneocuboid joint pain (14.7%). Porous titanium wedges in LCL can achieve good radiographic and clinical correction of AAFD with a low rate of nonunion and other complications.

LEVELS OF EVIDENCE

Level IV: Case series.

Calcaneocuboid Distraction Arthrodesis With Synthetic Bone Grafts: Preliminary Results of an Innovative Bone Grafting Procedure in 13 Patients

Calcaneocuboid distraction arthrodesis (CCDA) is regarded as an effective method for reconstructing adult-acquired flatfoot deformity. In the present study, we present our experience with newly developed rigid β-tricalcium phosphate wedges to treat CCDA to better understand the outcomes of this synthetic bone grafting procedure. A total of 13 feet in 13 patients underwent CCDA with synthetic bone grafts. One male (7.69%) and 12 females (92.31%), with a mean age of 65.07 ± 11.83 (range 36 to 77) years, were followed up for a mean duration of 32.76 ± 12.81 (range 18 to 55) months. Successful graft union was postoperatively obtained in 12 of the 13 feet (92.31%). The mean preoperative visual analog scale and American Orthopaedic Foot and Ankle Society scale score were 7.97 ± 1.52 (range 5.4 to 10) and 54.46 ± 14.72 (range 18 to 75), respectively. These scores improved to 1.52 ± 1.78 (range 0 to 6.2) and 85.46 ± 13.38 (range 50 to 97) postoperatively (p = .001 for both comparisons). On radiographic analysis, the talonavicular coverage angle, first metatarsal talar angle, calcaneal pitch, and heel alignment angle had significantly improved (p = .001, p = .028, p = .006, and p = .001, respectively). The use of bone graft substitutes in CCDA is a viable treatment option for reconstructing flexible flatfoot deformity. Although good clinical and radiographic outcomes were obtained, our method is even more challenging than conventional methods and should be used with caution. Rigid locking fixation with a long period of protected weightbearing is highly recommended to attain uneventful bone healing.

Comparative Outcomes Between Step-Cut Lengthening Calcaneal Osteotomy vs Traditional Evans Osteotomy for Stage IIB Adult-Acquired Flatfoot Deformity

BACKGROUND

The forefoot abduction component of the flexible adult-acquired flatfoot can be addressed with lengthening of the anterior process of the calcaneus. We hypothesized that the step-cut lengthening calcaneal osteotomy (SLCO) would decrease the incidence of nonunion, lead to improvement in clinical outcome scores, and have a faster time to healing compared with the traditional Evans osteotomy.

METHODS

We retrospectively reviewed 111 patients (143 total feet: 65 Evans, 78 SLCO) undergoing stage IIB reconstruction followed clinically for at least 2 years. Preoperative and postoperative radiographs were analyzed for the amount of deformity correction. Computed tomography (CT) was used to analyze osteotomy healing. The Foot and Ankle Outcome Scores (FAOS) and lateral pain surveys were used to assess clinical outcomes. Mann-Whitney U tests were used to assess nonnormally distributed data while χ² and Fisher exact tests were used to analyze categorical variables (α = 0.05 significant).

RESULTS

The Evans group used a larger graft size ( P < .001) and returned more often for hardware removal ( P = .038) than the SLCO group. SLCO union occurred at a mean of 8.77 weeks ( P < .001), which was significantly lower compared with the Evans group ( P = .02). The SLCO group also had fewer nonunions ( P = .016). FAOS scores improved equivalently between the 2 groups. Lateral column pain, ability to exercise, and ambulation distance were similar between groups.

CONCLUSION

Following SLCO, patients had faster healing times and fewer nonunions, similar outcomes scores, and equivalent correction of deformity. SLCO is a viable technique for lateral column lengthening.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Patient specific computational models to optimize surgical correction for flatfoot deformity

Several surgically corrective procedures are considered to treat Adult Acquired Flatfoot Deformity (AAFD) patients, relieve pain, and restore function. Procedure selection is based on best practices and surgeon preference. Recent research created patient specific models of AAFD to explore their predictive capabilities and examine effectiveness of the surgical procedure used to treat the deformity. The models' behavior was governed solely by patient bodyweight, soft tissue constraints, muscle loading, and joint contact without the assumption of idealized joints. The current work expanded those models to determine if an alternate procedure would be more effective for the individual. All procedures incorporated first a tendon transfer and then included one hindfoot procedure, the Medializing Calcaneal Osteotomy (MCO), and one of three lateral column procedures: Evans osteotomy, Calcaneocuboid Distraction Arthrodesis (CCDA), Z osteotomy, and the combination procedures MCO & Evans osteotomy, MCO & CCDA, and MCO & Z osteotomy. The combination MCO & Evans and MCO & Z procedures were shown to provide the greatest amount of correction for both forefoot abduction and hindfoot valgus. However, these two procedures significantly increased joint contact force, specifically at the calcaneocuboid joint, and ground reaction force along the lateral column. With exception to the lateral bands of the plantar fascia and middle spring ligament, the strain present in the plantar fascia, spring, and deltoid ligaments decreased after all procedures. The use of patient specific computational models provided the ability to investigate effects of alternate surgical corrections on restoring biomechanical function in these flatfoot patients. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1523-1531, 2017.

Calcaneal Z Lengthening Osteotomy Combined With Subtalar Arthroereisis for Severe Adolescent Flexible Flatfoot Reconstruction

BACKGROUND

The timing and strategy for operative treatment of flatfoot are still controversial. The purpose of this study was to evaluate clinical outcomes and radiographic changes following calcaneal Z osteotomy combined with subtalar arthroereisis for severe adolescent flexible flatfoot.

METHODS

Data were analyzed for 16 patients (20 feet) who had flatfoot without tibialis posterior tendon dysfunction and were treated by calcaneal Z osteotomy combined with arthroereisis between October 2011 and February 2015. The mean age of patients at the time of surgery was 12.8 ± 1.4 years (range, 10-14 years). Preoperative and postoperative measurements included changes in hindfoot valgus angles; changes in talonavicular uncoverage angles on anteroposterior (AP) radiographic view; and changes in talo-first metatarsal angles, talar pitch angles, and calcaneal pitch angles on lateral radiographic view. The American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Score (AOFAS-AH) was used to assess foot function. The mean follow-up was 18.9 ± 6.9 months (range, 13-33 months).

RESULTS

The hindfoot valgus angle improved from 14.9 ± 4.2 degrees to 2.3 ± 1.7 degrees. On the AP view, the preoperative and postoperative talonavicular uncoverage angles were 30.5 ± 9.4 degrees and 9.8 ± 4.8 degrees, respectively. On lateral radiographs, the preoperative talo-first metatarsal angle, talar pitch angle, and calcaneal pitch angle were -22.1 ± 7.9 degrees, 36.1 ± 4.4 degrees, and 14.4 ± 4.0 degrees, respectively. Postoperative lateral radiographs demonstrated talo-first metatarsal angle, talar pitch angle, and calcaneal pitch angle of -6.2 ± 4.7 degrees, 27.3 ± 4.9 degrees, and 19.0 ± 4.3 degrees, respectively. The AOFAS-AH score improved from 66.8 ± 24.1 preoperatively to 96.5 ± 3.4 postoperatively.

CONCLUSIONS

For adolescents with flatfoot, calcaneal Z osteotomy combined with subtalar arthroereisis provided satisfactory results.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Autograft versus sterilized allograft for lateral calcaneal lengthening osteotomies: Comparison of 50 patients

Sterilized allografts may be less resistant to collapse and prone to nonunion leading to loss of correction in open wedge osteotomies. These adverse events usually occur at early time points (i.e., < 9 months postoperatively). The goal of this study was to compare sterilized allografts to autologous grafts in respect to secondary loss of hindfoot alignment and graft incorporation after lateral calcaneal lengthening osteotomies.Fifty patients (22 F/ 28 M, age: 16-69 years) who had undergone 50 lateral calcaneal lengthening osteotomies for adult flatfoot deformity were included in this retrospective study. Cortical sterilized allografts were used in 25 patients, autologous grafts in the remaining 25. Patients' preoperative, 6 and 12 weeks, and 6 to 9 months follow-up weight-bearing radiographs of the affected foot were analyzed by 2 blinded radiologists: on each radiograph, graft incorporation, the talo-first metatarsal angle (TFMA), the talo-navicular coverage angle (TNCA), and the calcaneal pitch angle (CPA) were assessed. Loss of hindfoot alignment was defined as an increase of the TFMA or the TNCA or a decrease of the CPA, each by 5°.Inter- and intraclass correlation coefficients for TFMA, TNCA, and CPA measurements ranged from 0.93 to 0.99. At all follow-up visits, the ratio of patients with loss of hindfoot alignment and graft incorporation was not significantly different between the allograft and autograft group. However, loss of correction was associated with failure of graft incorporation.Compared with autografts, sterilized allografts do not increase the risk for loss of hindfoot alignment in lateral column lengthening of the calcaneus. With respect to mechanical resistance, allografts thus mean an equal and valid alternative without risk of donor site morbidities.

Contribution of Lateral Column Lengthening to Correction of Forefoot Abduction in Stage IIb Adult Acquired Flatfoot Deformity Reconstruction

BACKGROUND

Correction of forefoot abduction in stage IIb adult acquired flatfoot likely depends on the amount of lateral column lengthening (LCL) performed, although this represents only one aspect of a successful reconstruction. The purpose of this study was to evaluate the correlation between common reconstructive variables and the observed change in forefoot abduction.

METHODS

Forty-one patients who underwent flatfoot reconstruction involving an Evans-type LCL were assessed retrospectively. Preoperative and postoperative anteroposterior (AP) radiographs of the foot at a minimum of 40 weeks (mean, 2 years) after surgery were reviewed to determine correction in forefoot abduction as measured by talonavicular coverage (TNC) angle, talonavicular uncoverage percent, talus-first metatarsal (T-1MT) angle, and lateral incongruency angle. Fourteen demographic and intraoperative variables were evaluated for association with change in forefoot abduction including age, gender, height, weight, body mass index, as well as the amount of LCL and medializing calcaneal osteotomy performed, LCL graft type, Cotton osteotomy, first tarsometatarsal fusion, flexor digitorum longus transfer, spring ligament repair, gastrocnemius recession and any one of the modified McBride/Akin/Silver procedures.

RESULTS

Two variables significantly affected the change in lateral incongruency angle. These were weight (P = .04) and the amount of LCL performed (P < .001). No variables were associated with the change in TNC angle, talonavicular uncoverage percent, or T-1MT angle. Multivariate regression analysis revealed that LCL was the only significant predictor of the change in lateral incongruency angle. The final regression model for LCL showed a good fit (R2 = 0.70, P < .001). Each millimeter of LCL corresponded to a 6.8-degree change in lateral incongruency angle.

CONCLUSION

Correction of forefoot abduction in flatfoot reconstruction was primarily determined by the LCL procedure and could be modeled linearly. We believe that the lateral incongruency angle can serve as a valuable preoperative measurement to help surgeons titrate the proper amount of correction performed intraoperatively.

Radiographic Outcomes Following Lateral Column Lengthening With a Porous Titanium Wedge

BACKGROUND

Lateral column lengthening (LCL) is commonly utilized in treating stage II posterior tibialis tendon dysfunction. This study aimed to analyze the outcomes of LCL with porous titanium wedges compared to historic controls of iliac crest autograft and allograft. We hypothesized that the use of a porous titanium wedge would have radiographic improvement and union rates similar to those with the use of autograft and allograft in LCL.

METHODS

Between May 2009 and May 2014, 28 feet in 26 patients were treated with LCL using a porous titanium wedge. Of the 26 patients, 9 were males (34.6%). The average age for males was 43 years (range, 17.9-58.7), 48.7 years (range, 21-72.3) for females. Mean follow-up was 14.6 months. Radiographs were examined for correction of the flatfoot deformity and forefoot abduction. All complications were noted.

RESULTS

Radiographically, the patients had a significant deformity correction in the anteroposterior talo-first metatarsal angle, talonavicular coverage angle, lateral talo-first metatarsal angle, and calcaneal pitch. All but 1 patient (96%) had bony incorporation of the porous titanium wedge. The average preoperative visual analog scale pain score was 5; all patients but 3 (12%) had improvements in their pain score, with a mean change of 3.4.

CONCLUSION

LCL with porous titanium had low nonunion rates, improved radiographic correction, and pain relief.

LEVEL OF EVIDENCE

Level IV, case series.

Outcomes of a Stepcut Lengthening Calcaneal Osteotomy for Adult-Acquired Flatfoot Deformity

BACKGROUND

Lateral column lengthening is used to correct abduction deformity at the midfoot and improve talar head coverage in patients with flatfoot deformity. It was our hypothesis that following a stepcut lengthening calcaneal osteotomy (SLCO), patients would have adequate correction of the deformity, a high union rate of the osteotomy, and improvement in clinical outcome scores.

METHODS

We retrospectively reviewed 37 consecutive patients who underwent SLCO for the treatment of stage IIB flatfoot deformity with a minimum 2-year follow-up. Deformity correction was assessed using preoperative and postoperative weight-bearing radiographs. Healing of the osteotomy was assessed by computed tomography. Clinical outcomes included the FAOS and SF-36 questionnaires. The Wilcoxon signed-rank test was used to compare clinical outcome scores. An alpha level of .05 was deemed statistically significant.

RESULTS

Healing of the osteotomy occurred at a mean of 7.7 weeks postoperatively. The talonavicular (TN) coverage angle improved from 34.0 to 8.8 (P < .001), the percentage of TN uncoverage improved from 40.9% to 17.7% (P < .001), and the TN incongruency angle improved from 68.1 to 8.7 (P < .001). In addition, there was an improvement in FAOS pain (P < .001), daily activities (P < .001), sport activities (P = .006), and quality of life scores (P < .001). Overall SF-36 scores also showed improvement postoperatively (P < .001). There was no incidence of delayed union, nonunion, or graft collapse.

CONCLUSION

Following SLCO, patients demonstrated excellent healing, good correction of the deformity, and improvement in clinical outcomes scores. The SLCO is an alternative to the Evans osteotomy for lateral column lengthening.

LEVEL OF EVIDENCE

Level IV, retrospective case review.

Lateral column lengthening corrects hindfoot valgus in a cadaveric flatfoot model

BACKGROUND

Adult-acquired flatfoot deformity requires a complex operative plan that often utilizes a number of procedures to correct deformity, at both the hindfoot and midfoot. A lateral column lengthening procedure is typically performed to correct abduction deformity across the talonavicular joint; however its effect on hindfoot alignment is not well understood, and overcorrecting the hindfoot deformity can lead to pain and revision surgeries. Therefore, understanding the effect of lateral column lengthening on hindfoot alignment is important for operative planning. The aim of this study was to demonstrate the effect of a lateral column lengthening osteotomy on hindfoot valgus in a simulated flatfoot model.

METHODS

A flatfoot deformity was created in 12 lower limb cadaveric specimens. A step-cut lateral column lengthening osteotomy was performed and changes in hindfoot and midfoot alignment were measured using a motion capture system.

RESULTS

The lateral column lengthening procedure corrected 60% of the hindfoot valgus deformity (P < .001). In addition, the abduction deformity at the midfoot was completely corrected with the procedure (P < .001).

CONCLUSION

Our findings suggest that the lateral column lengthening procedure corrects hindfoot valgus, in addition to midfoot abduction, in a flatfoot deformity.

CLINICAL RELEVANCE

Understanding the relative contribution of each operative procedure to the overall deformity correction in flatfoot reconstruction will allow surgeons to accurately correct the foot into a plantigrade position while minimizing the risk of overcorrection.

Graft shape affects midfoot correction and forefoot loading mechanics in lateral column lengthening osteotomies

BACKGROUND

Adult acquired flatfoot deformity is characterized by midfoot abduction and collapse of the medial longitudinal arch. Lateral column lengthening osteotomies primarily correct the abduction deformity, but the effects of graft shape on deformity correction and forefoot loading are unclear. Therefore, the purpose of this study was to demonstrate the effect of graft shape and taper on deformity correction and forefoot loading mechanics in a cadaveric flatfoot model.

METHODS

Flatfoot deformity was simulated in 18 cadaveric specimens. A lateral column lengthening osteotomy was performed using a triangular, trapezoidal, and rectangular graft for each specimen. During each testing condition, talonavicular joint angles and forefoot plantar pressures were measured.

RESULTS

Each graft shape corrected abduction and dorsiflexion deformity at the talonavicular joint. Coronal plane correction was affected by graft shape, and the less tapered trapezoidal and rectangular grafts overloaded the lateral forefoot compared to the intact condition. The more tapered triangular graft did not cause a lateral shift in forefoot pressures. Forefoot plantar pressures were strongly correlated with talonavicular abduction correction (R (2) = .473, P < .001).

CONCLUSION

Graft shape had no effect on the correction of talonavicular abduction or dorsiflexion but did influence coronal plane motion and forefoot loading mechanics. Also, overcorrecting the abduction deformity was predictive of increased lateral plantar pressures.

CLINICAL RELEVANCE

Although overcorrection of the abduction deformity at the midfoot remains the primary determinant of lateral forefoot overload, utilizing a graft with a larger taper may lower the incidence of lateralized forefoot pressure following correction.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSION

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.

CLINICAL RELEVANCE

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.

Clinical outcomes and static and dynamic assessment of foot posture after lateral column lengthening procedure

BACKGROUND

Lateral column lengthening (LCL) has been shown to radiographically restore the medial longitudinal arch. However, the impact of LCL on foot function during gait has not been reported using validated clinical outcomes and gait analysis.

METHODS

Thirteen patients with a stage II flatfoot who had undergone unilateral LCL surgery and 13 matched control subjects completed self-reported pain and functional scales as well as a clinical examination. A custom force transducer was used to establish the maximum passive range of motion of first metatarsal dorsiflexion at 40 N of force. Foot kinematic data were collected during gait using 3-dimensional motion analysis techniques.

RESULTS

Radiographic correction of the flatfoot was achieved in all cases. Despite this, most patients continued to report pain and dysfunction postoperatively. Participants post LCL demonstrated similar passive and active movement of the medial column when we compared the operated and the nonoperated sides. However, participants post LCL demonstrated significantly greater first metatarsal passive range of motion and first metatarsal dorsiflexion during gait than did controls (P < .01 for all pairwise comparisons).

CONCLUSION

Patients undergoing LCL for correction of stage II adult-acquired flatfoot deformity experience mixed outcomes and similar foot kinematics as the uninvolved limb despite radiographic correction of deformity. These patients maintain a low arch posture similar to their uninvolved limb. The consequence is that first metatarsal movement operates at the end range of dorsiflexion and patients do not obtain full hindfoot inversion at push-off. Longitudinal data are necessary to make a more valid comparison of the effects of surgical correction measured using radiographs and dynamic foot posture during gait.

LEVEL OF EVIDENCE

Level III, comparative series.

Autograft and allograft unite similarly in lateral column lengthening for adult acquired flatfoot deformity

BACKGROUND

Lateral column lengthening (LCL) is used to address the forefoot abduction associated with the adult acquired flatfoot. This opening wedge osteotomy can be filled with either allograft or autograft bone.

QUESTIONS/PURPOSES

The investigators sought to determine union rates and any loss of correction in patients undergoing LCL with autograft versus allograft.

METHODS

Over a 3-year period, 126 LCLs performed by five surgeons in 120 patients were reviewed. Autograft was used in 51 patients, allograft in 75 patients. Times to clinical and radiographic union were established for these patients. Any loss of correction of forefoot abduction as manifested by talonavicular uncoverage was recorded for those grafts that healed. Failure was defined as nonunion or loss of 50% or greater correction. The size of the implanted graft was assessed as a risk factor for failure.

RESULTS

There were 20 total failures: seven in patients with autograft and 13 in patients with allograft (p = 0.63). The size of the implanted graft was larger in those patients that did fail (p = 0.04).

CONCLUSIONS

The rate of nonunion and loss of correction for LCL was not significantly different between allograft and autograft. The overall rate of nonunion may be higher than has previously been reported.

Effects of surgical correction for the treatment of adult acquired flatfoot deformity: a computational investigation

Computational models of the foot/ankle complex were developed to predict the biomechanical consequences of surgical procedures that correct for stage II adult acquired flatfoot deformity. Cadaveric leg and foot bony anatomy was captured by CT imaging in neutral flexion and imported to the modeling software. Ligaments were approximated as tension only springs attached at insertion sites. Muscle contraction of the gastrocnemius/soleus complex was simulated through force vectors and desired external loads applied to the model. Ligament stiffnesses were modified to reflect stage II flatfoot damage, followed by integration of corrective osteotomies-medializing calcaneal osteotomy (MCO) and Evans and calcaneocuboid distraction arthrodesis (CCDA)--to treat flatfoot. Joint angles, tissue strains, calcaneocuboid contact force, and plantar loads were analyzed. The flatfoot simulation demonstrated clinical signs of disease evidenced by degradation of joint alignment. Repair states corrected these joint misalignments with MCO having greatest impact in the hindfoot, and Evans/CCDA having greatest effect in the mid- and forefoot. The lateral procedures unevenly strained plantar structures, while offloading the medial forefoot, and increased loading on the lateral forefoot, which was amplified by combining with MCO. The Evans procedure raised calcaneocuboid joint contact force to twice intact levels. Computational results are in agreement with clinical and experimental findings. The model demonstrated potential precursors to such complications as lateral tightness and arthritic development and may thus be useful as a predictor of surgical outcomes.