Spring Ligament Research Articles

Indications and Limitations of Synthetic Ligament Augmentation Among Foot and Ankle Surgeons and Other Orthopedic Subspecialties

Category: Sports; Ankle; Trauma; Other Introduction/Purpose: Ligament augmentation repair (LAR) entails supplementing a ligament repair with synthetic material anchored to bone. Purported advantages include increased stability and a more aggressive rehabilitation. In recent years, the literature supporting LAR has grown rapidly, with published techniques and outcomes for many ligament and tendon repairs, including anterior talofibular ligament (ATFL), Achilles tendon, and the spring ligament complex. Despite the increased use of synthetic ligaments reported in literature, there remains a lack of clarity and consensus on the indications and postoperative rehabilitation protocols. The purpose of this study was to survey an international group of orthopedic specialists regarding their current use of LAR techniques and decision-making. Methods: We invited members of several international orthopaedic and sports medicine societies to participate in this survey between January and June 2021. Responding surgeons represented all six continents, and included 319 sports medicine specialists, 179 foot and ankle specialists, and 96 trauma specialists (some reported more than one fellowship). Survey questions fell into three general categories: 1) Surgeon demographics and training, 2) Current LAR use decision-making within respondents' subspecialty, and 3) Outcomes, complications, frequency, and benefits associated with LAR. Chi-square tests of independence were used to assess the likelihood of any dependent relationships between respondent demographics and LAR use our outcome. A p value of less than 0.05 was considered significant. Results: We collected 515 responses total with a 97% completion rate. 75% of all survey respondents report using LAR for some indication. The most frequent use was ATFL repair (69%, Figure 1). LAR is most commonly implemented for additional stability (72%), poor tissue quality (54%), and more rapid return-to-sport/work (47%). LAR users state the greatest limitation is cost (62%), while non-LAR users state their greatest deterrent to LAR is that it is unnecessary for a good outcome (46%). Foot and ankle fellowship trained surgeons are significantly more likely to use LAR (87% use LAR) compared to sports-trained surgeons (67%, p = 0.002) and surgeons without a fellowship (66% use LAR, p = 0.01). Surgeons treating professional/Olympic athletes are significantly more likely to use LAR. Conclusion: While synthetic ligaments are commonly used to supplement ligament repairs, the application, outcomes, and perceived benefit differ for each subspecialty. The reported limitations of LAR differ between LAR users and non-LAR users. For those who do not use LAR, the greatest limitation is perceived benefit, while for those that do, the greatest limitation is cost. Prospective studies of indications, outcomes and accelerated rehabilitation protocols are needed to further elucidate the value and cost-effectiveness of these implants.

2022 J. Leonard Goldner Award Winner: Passive Eversion Assessment for Progressive Collapsing Foot Deformity after Lateral Column Lengthening: A Cadaveric Biomechanical Study

Category: Hindfoot; Midfoot/Forefoot; Other Introduction/Purpose: Lateral column lengthening (LCL) is an established procedure for progressive collapsing foot deformity (PCFD) patients. While functional improvements are often reported after LCL, increased post-surgical lateral foot pain, attributed to decreased subtalar joint motion, remains a concern. The optimal wedge size is determined intraoperatively by measuring passive eversion of the hindfoot to ensure adequate eversion motion and radiographic correction. However, it is unknown whether a subjective assessment of passive eversion is associated with objective postoperative measurements of foot stiffness, such as plantar pressure. Our goal was to quantify the relationship between eversion during a passive assessment and plantar pressures during simulations of level walking. We hypothesized that a strong relationship exists between the location of plantar pressure and the eversion measured with passive manipulation. Methods: A deformity was created in ten mid-tibia cadaveric specimens (four female, age range: 35-72) by transecting the spring ligament and medial talonavicular joint capsule followed by cyclic loading. A six degrees-of-freedom robotic gait simulator was used to simulate the stance phase of level walking. Joint kinematics and plantar pressure data were collected during each simulation. A passive assessment of hindfoot eversion was then conducted manually by a fellowship-trained orthopaedic surgeon and recorded by the motion capture system. Five conditions were tested: intact, PCFD, and three LCL wedge conditions (4, 6, 8mm). Outcome measures for each condition included the lateral-to-medial forefoot plantar pressure ratio during walking simulations and the peak subtalar eversion measured during the assessment. A linear mixed effects model was used to determine the association between the plantar pressure and LCL wedge thickness. Pearson correlation coefficients were calculated to determine the relationship between subtalar eversion and plantar pressure. Results: There was a significant relationship between the size of LCL wedge and the forefoot lateral-to-medial average pressure ratio (p<0.001). Every 2mm increase in LCL wedge size resulted in a 0.20 +- 0.03 increase in the LM ratio, indicating a significant lateral shift in plantar pressure with each increase in wedge size. The 4mm wedge was most effective in restoring plantar pressure and eversion to intact (Figure 1). The peak subtalar eversion measured during the assessment decreased with an increase in the size of the LCL wedge. A strong correlation (r(38)=0.51, p<0.01) was found between the LM ratio and the peak subtalar eversion. This indicates that a decrease in the eversion measured during passive assessment is strongly associated with a lateral shift in plantar pressure. Conclusion: This study demonstrates that reduced eversion following LCL is associated with increased lateral plantar pressure which is consistent with stiffness and lateral plantar pain that is a well-known complication of this surgery. Passive eversion measurement is likely to help predict functional performance. The 4mm wedge best restored outcomes to normal, whereas larger wedges resulted in increased lateral loading and decreased eversion. A change in correction of 2mm made a significant difference in loss of eversion motion and minimizing the amount of lengthening is strongly recommended.

Tratamiento quirúrgico del pie plano valgo adquirido del adulto en estadio IIB: papel de la reparación del «spring ligament»

Background and aimsThe spring ligament has paramount role in supporting the arches and its fail causes the collapse of the medial longitudinal arc, inducing adult acquired flatfoot deformity. Our aim was to analyze the clinical and radiological outcomes of spring ligament repair and titanium wedges integration used in surgical osteotomies. Material and methodsWe performed a retrospective study of 23 cases with middle ages of 63, diagnosed with adult acquired flatfoot deformity stage IIB in RAM classification after ortho-prosthetic treatment failure, assessing the functional outcomes using the American Orthopedic Foot and Ankle Society scale and the radiological outcomes studying angles variation (talonavicular uncoverage, talo-first metatarsal angle and Meary axis). ResultsThe mean preoperative American Orthopedic Foot and Ankle Society score of the sample was 52±10 and the postoperative 88±6 (p<0.05). The radiological outcomes showed a statistically significant improvement. ConclusionSpring ligament repair associated to bone reconstruction offers large functional and radiological outcomes to adult acquired flatfoot deformity stage IIB treatment. Titanium wedges present an excellent bone integration.

Significance of the anatomical relationship between the flexor digitorum longus and sustentaculum tali for reconsideration of the talocalcaneonavicular joint stability mechanism

The talocalcaneonavicular joint (TCN-j) is supported by the spring ligament, which has recently been revealed to be part of the joint capsule complex, along with the tendinous sheath of the tibialis posterior and flexor digitorum longus (FDL). Nonetheless, the FDL’s role in TCN-j stability has received limited attention. This study aimed to elucidate the positional relationships between the FDL and sustentaculum tali, which comprises the TCN-j. We hypothesized that the FDL runs medial to the sustentaculum tali, and its course significantly changes from the sitting to the standing position. Six ankles from six body donors were investigated, and seven ankles from seven volunteers were assessed using ultrasonography. The FDL was three-dimensionally located inferomedial to the sustentaculum tali. The FDL tendinous sheath was attached to the sustentaculum tali or connected by the tibialis posterior via the tendinous sheath. Based on the in vivo ultrasound image, the FDL location relative to the sustentaculum tali was maintained; however, the curvature of the FDL course was significantly more prominent in standing than in sitting. The FDL force against the bending moment may prevent the excessive eversion of the foot and aid the conventional spring ligament’s contribution to TCN-j stability for maintaining the longitudinal arch.

Effects Of Low-Dye Taping On Plantar Fascia Strain And Kinematics In Individuals With Plantar Fasciitis

Plantar fasciitis is thought to be caused by excessive strain of the plantar fascia, which may occur due to altered foot kinematics displayed by individuals with plantar fasciitis. The low-Dye taping method has been found to be effective at reducing pain and increasing function in individuals with plantar fasciitis, although the exact mechanisms for these changes are unclear. PURPOSE: To determine the effects of low-Dye taping on plantar fascia strain and foot kinematics in individuals with plantar fasciitis. METHODS: Fifteen adults with plantar fasciitis completed the repeated measures study. Each participant walked barefoot at a self-selected speed while untaped and while their pathological foot was taped with the low-Dye taping method. A six-segment musculoskeletal model of the foot was used to provide estimates of plantar fascia and other foot ligament strains. Statistical Parametric Mapping (SPM) was used to compare plantar fascia strain, and post hoc SPM analyses of several foot joint kinematics were conducted to explain the differences in plantar fascia strain. Finally, strains of several foot ligaments were investigated using SPM procedures. RESULTS: Significantly greater plantar fascia strain was found during the untaped condition between 67-79% of stance phase (p = 0.001), which does not include the time in which peak strain occurred. The low-Dye taping method also reduced dorsiflexion of the talonavicular joint from 52-86% of stance phase (p < 0.001), which represents a reduction in arch collapse. In addition, significant strain reductions in the taped condition were noted in the superior and inferior slips of the spring ligament from 14-87% (p < 0.001) and 16-87% (p < 0.001) of stance phase, respectively, as well as in the 2nd, 3rd, and 4th slips of the long plantar ligament from 56-86% (p < 0.001), 59-86% (p < 0.001), and 68-81% (p < 0.001) of stance phase, respectively. CONCLUSIONS: Our findings suggest that if low-Dye taping is effective for individuals with plantar fasciitis, it is not by reducing peak plantar fascia strain, but instead by reducing cumulative strain across the entire stance phase. This reduction in strain during stance phase occurs due to the reduction in arch collapse. Furthermore, several other ligaments are significantly affected by the low-Dye taping method.

Deltoid and Spring Ligament Reconstruction: The Quadrangular Construct

Deltoid and Spring Ligament Reconstruction: The Quadrangular Construct

A computational model of force within the ligaments and tendons in progressive collapsing foot deformity.

Progressive collapsing foot deformity results from degeneration of the ligaments and posterior tibial tendon (PTT). Our understanding of the relationship between their failures remains incomplete. We sought to improve this understanding through computational modeling of the forces in these soft tissues. The impact of PTT and ligament failures on force changes in the remaining ligaments was investigated by quantifying ligament force changes during simulated ligament and tendon cutting in a validated finite element model of the foot. The ability of the PTT to restore foot alignment was also evaluated by increasing the PTT force in a foot with attenuated ligaments and comparing the alignment angles to the intact foot. We found that failure of any one of the ligaments led to overloading the remaining ligaments, except for the plantar naviculocuneiform, first plantar tarsometatarsal, and spring ligaments, where removing one led to unloading the other two. The combined attenuation of the plantar fascia, long plantar, short plantar, and spring ligaments significantly overloaded the deltoid and talocalcaneal ligaments. Isolated PTT rupture had no effect on foot alignment but did increase the force in the deltoid and spring ligaments. Moreover, increasing the force within the PTT to 30% of body weight was effective at restoring foot alignment during quiet stance, primarily through reducing hindfoot valgus and forefoot abduction as opposed to improving arch collapse. Our findings suggest that early intervention might be used to prevent the progression of deformity. Moreover, strengthening the PTT through therapeutic exercise might improve its ability to restore foot alignment.

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.

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

Ability of the Posterior Tibial Tendon to Restore Foot Alignment in Progressive Collapsing Foot Deformity: A Computational Study

Category:Ankle; Midfoot/Forefoot; OtherIntroduction/Purpose:Progressive collapsing foot deformity (PCFD) is a degenerative disorder of ligaments and tendons that encompasses a wide range of deformities, including arch height loss, hindfoot valgus, and forefoot abduction. The posterior tibial tendon (PTT) is the main active stabilizer of the arch. We hypothesize that it may become injured secondarily as it attempts to maintain foot stability when the ligaments, passive stabilizers, are attenuated. Several cadaveric studies have been conducted on the role of the PTT in PCFD, but the ability of the PTT to compensate for the loss of the ligamentous stabilizers has not been clearly characterized. We developed a high-fidelity finite element model of the foot to determine the PTT's ability to maintain foot stability when the principle ligamentous stabilizers are attenuated.Methods:The encapsulating soft tissue (EST), cartilage, and cortical and trabecular bones were reconstructed in Mimics from CT scan images of a female cadaveric foot weighing 60 kg. Tension-only spring elements were used to reflect all the ligaments in ANSYS. Bodyweight and tendon forces were applied using force vectors in the direction of their lines of action. The proximal tibia was fixed only in the vertical direction, allowing it to translate and rotate in all other degrees of freedom. Nonlinear frictional contacts were used between the EST and the ground, and between the cartilages. The flatfoot was simulated by removing all of the ligaments. We measured the foot alignment angles for the flatfoot and the foot with ruptured spring/deltoid ligament, while we gradually increased the force within the PTT. The measured angles were then compared to the intact foot to evaluate the ability of the PTT to restore foot alignment.Results:The models were validated by comparing the Meary's (MA), calcaneal pitch (CPA), hindfoot alignment (HAA), and talonavicular coverage angles (TCA) to clinically-derived values. In the flatfoot, an increase of the PTT force to approximately 700% of normal ('7 ×25.71 N=180 N') led to a nearly complete restoration of foot alignment (Fig. 1). The angles associated with arch height (MA/CPA) were restored to a lesser extent than those associated with hindfoot and forefoot alignment (HAA/TCA). For the foot with ruptured deltoid ligament, increasing force within the PTT by 500% led to a restoration of near normal hindfoot alignment (Fig. 1c). For the foot with ruptured spring ligament, the forefoot abduction was completely compensated only when the PTT force was increased to 1100% of normal (Fig. 1d).Conclusion:Almost seven times the normal PTT force is required to restore the foot to neutral alignment. Augmentation of PTT force to this extent is unrealistic. However, a lesser increase in PTT force provides partial alignment compensation.Furthermore, the restoration achieved by overloading the PTT primarily impacts the alignment of the hindfoot and forefoot rather than the arch. Because the PTT can partially restore foot alignment, it may become secondarily injured when the ligaments are torn. Strengthening of the PTT through therapeutic exercise can improve its ability to restore foot alignment and should be a cornerstone of non-operative treatment of PCFD.

Bone marrow edema of the medioplantar talar head is associated with severe ligamentous injury in ankle sprain

PurposeTo investigate the predictive value of talar head edema (THE) in acute ankle sprain for the presence of concomitant ligament injuries.MethodsThis retrospective study was approved by the ethics committee and informed consent was obtained. One hundred patients (mean age: 37 years ± 14 [standard deviation], range 13–77 years) with MRI of the ankle after acute trauma were included. The cohort in this matched-pair study consisted of 50 patients with THE (group 1) and 50 patients without THE (group 2). Two readers independently evaluated presence and size of bone marrow edema of the talus head and injuries of the lateral, medial, talonavicular, and spring ligament complex. Statistics included intraclass correlation coefficient (ICC) and Kappa statistics as well as parametric and non-parametric tests.ResultsOn average, patients with THE demonstrated significantly more ligament injuries in comparison to patients without THE (3.7 vs. 1.3, p ≤ 0.01). Also, in patients with THE, the number of injured ligaments was significantly higher at the lateral (p = 0.03), medial (p ≤ 0.01), and talonavicular (p ≤ 0.01) compartment in comparison to patients without THE. The most frequently injured ligaments in patients with THE were the anterior talofibular ligament (60%) and the anterior tibiotalar ligament (42%). There was no significant correlation between edema size and the number of injured ligaments or compartments (p = 0.5).ConclusionTHE is associated with more extensive ligamentous ankle injury, in particular to the medial and lateral collateral ligament complex, and therefore indicative of severe ankle trauma.

The impact of ligament tears on joint contact mechanics in progressive collapsing foot deformity: A finite element study

BackgroundPatients with longstanding progressive collapsing foot deformity often develop osteoarthritis of the ankle, midfoot, or hindfoot joints, which can be symptomatic or lead to fixed deformities that complicate treatment. The development of deformity is likely caused by ligament degeneration and tears. However, the effect of individual ligament tears on changes in joint contact mechanics has not been investigated. MethodsA validated finite element model of the foot was used to compare joint contact areas, forces, and pressures between the intact and collapsed foot, and to evaluate the effect of individual ligament tears on joint contact mechanics. FindingsCollapsing the foot resulted in an increase in contact pressure in the subtalar, calcaneocuboid, tibiotalar, medial naviculocuneiform, and first tarsometatarsal joints but a decrease in contact pressure in the talonavicular joint. Rupture of the spring ligament was the main contributor to increased calcaneocuboid and subtalar joint contact pressures and decreased medial naviculocuneiform and first tarsometatarsal joint contact pressures, as well as talonavicular subluxation. Deltoid ligament rupture was the primary source of increased contact pressure in the medial naviculocuneiform, first tarsometatarsal, and tibiotalar joints. InterpretationDegenerative tearing of the ligaments in flatfoot deformity leads to increased joint contact pressures, primarily in the calcaneocuboid, subtalar, and tibiotalar joints, which has been implicated in the development of osteoarthritis in these joints. An improved understanding of the relationship between ligament tears and joint contact pressures could provide support for the use of ligament reconstructions to prevent the development of arthrosis.

The contribution of the ligaments in progressive collapsing foot deformity: A comprehensive computational study.

The contribution of each of the ligaments in preventing the arch loss, hindfoot valgus, and forefoot abduction seen in progressive collapsing foot deformity (PCFD) has not been well characterized. An improved understanding of the individual ligament contributions to the deformity would aid in selecting among available treatments, optimizing current surgical techniques, and developing new ones. In this study, we evaluated the contribution of each ligament to the maintenance of foot alignment using a finite element model of the foot reconstructed from computed tomographyscan images. The collapsed foot was modeled by simulating the failure of all the ligaments involved in PCFD. The ligaments were removed one at a time to determine the impact of each ligament on foot alignment, and then restored one at a time to simulate isolated reconstruction. Our findings show that the failure of any one ligament did not immediately lead to deformity, but that combined failure of only a few (the plantar fascia, long plantar, short plantar, deltoid, and spring ligaments) could lead to significant deformity. The plantar fascia, deltoid, and spring ligaments were primarily responsible for the prevention of arch collapse, hindfoot valgus, and forefoot abduction, respectively. Moreover, to produce deformity, a considerable amount of attenuation in the spring, tibiocalcaneal, interosseous talocalcaneal, plantar naviculocuneiform, and first plantar tarsometatarsal ligaments, but only a small amount in the plantar fascia, long plantar, and short plantar ligaments was needed. The results of this study suggest that the ability of a ligament to prevent deformity may not correlate with its attenuation in a collapsed foot.

Tarsal Tunnel Syndrome Following Medializing Calcaneal Osteotomy

Category:HindfootIntroduction/Purpose:The tarsal tunnel syndrome is a compressive neuropathy that affects either the posterior tibial nerve, within the tarsal tunnel, or one of its terminal branches. It can be caused by extrinsic or intrinsic factors. Even though the tarsal tunnel syndrome has been reported as a complication of lateralizing calcaneal osteotomy, we have not identified in the literature reports of this syndrome associated to medializing calcaneal osteotomy. We report the case of a 60-year-old female who developed a tarsal tunnel syndrome, on the third postoperative week, following a medializing calcaneal osteotomy for flatfoot correction with stage IIB posterior tibial tendon dysfunction.Methods:We reviewed and obtained the information from the medical records of this patient: clinical examination, radiographs, computed tomography, magnetic resonance imaging, and outcome. Pain was assessed with visual analog scale (VAS).Results:The patient is a 60-year-old female with left stage II posterior tibial tendon dysfunction who failed to respond to conservative treatment. Medializing and lengthening (Evans) osteotomies of the calcaneus were performed, together with posterior tibial tendon repair and spring ligament reconstruction. In the postoperative, after a cast replacement into a more plantigrade position, the patient developed symptoms that suggested a compressive neuropathy of posterior tibial nerve within the tarsal tunnel associated to calcaneal medializing osteotomy. Initial conservative treatment failed and the posterior tibial nerve was explored under loupe magnification and the tarsal tunnel was released. Figure 1. An immediate improvement in pain was observed postoperatively and almost full recovery occurred within 6 months.Conclusion:In our case report, the tarsal tunnel syndrome was a consequence of the osteotomy fragment displacement that generated a reduction of the tarsal tunnel volume. It has been described that the tarsal tunnel syndrome symptoms become more evident with ankle dorsiflexion and eversion, in our patient this can be associated with the symptom exacerbation presented when the cast was placed into plantigrade position. We conclude that even though in the literature the tarsal tunnel syndrome has been mainly associated to lateralizing osteotomies, it is important to take this complication into account when performing a medializing osteotomy.

Effect of Medial Ligament Reconstruction in Flatfoot Deformity: How It Affects the Soft Tissue Improvement and Radiological Outcome of the Surgery?

Category:Ankle; Hindfoot; SportsIntroduction/Purpose:Surgical treatment of adult flatfoot deformity has traditionally be driven by tendon transfers and osteotomy. In acquired deformity, injury to the spring ligament and superficial deltoid ligament is common. The procedures mentioned previously do nothing to restore the function of the medial ligament complex. Studies have shown that reconstruction of the medial ligament complex, and thus the medial talonavicular joint, has benefit to patient outcomes. The question still remains of how much correction the medial ligament reconstruction confers on its own. The purpose of this study is to compare isolated medial ligament reconstruction procedures to other flat foot correcting procedures in the treatment of acquired flat foot deformity.Methods:18 patients were identified that underwent procedure for flatfoot deformity. Of these patients there were 7 patients that underwent isolated medial ligament complex reconstruction and 11 patients that underwent non-tendon transfer procedure for correction of flat foot deformity. Imaging was performed on patient's weight bearing (WB) and non-weight bearing (NWB) before and after surgery. Measurements included Angles: calcaneal pitch, talo-1st metatarsal, talocalcaneal, talar declination, calcaneal 1st metatarsal and Distances: talar height, navicular height, 1st cuneiform height, cuboid height, and 1st to 5th metatarsal distance in lateral X-ray, and Angles: talonavicular coverage, talar 1st metatarsal, talar 2nd metatarsal and Distances: talonavicular uncoverage distance in AP. The differences in measurement between the pre-op and post-op non-weight bearing are considered as bony correction effect while differences between pre-op and post-op weight bearingare considered as soft tissue correctionResults:For non-weight bearing; medial ligament reconstruction impact was seen on calcaneal pitch (19 to 35 degrees, p=0.007), 1st cuneiform height (21 to 28mm, p=0.016), talonavicular coverage (6 to 3 degrees, p=0.026), and Talar 1st metatarsal angle (14 to 7 degrees, p=0.008). Other corrections had an impact on calcaneal pitch (15 to 24 degrees, p=0.006), Talo-1st metatarsal angle (11 to 6 degrees, p=0.019), Calcaneal 1st metatarsal (139 to 129 degrees, p=0.044), Talar height (31 to 42mm, p=0.001), navicular height (24 to 34mm, p=0.002), and 1st cuneiform height (18 to 22mm, p=0.016). For weight bearing; reconstruction impact was seen on talocalcaneal angle (36 to 44 degrees, p=0.011), 1st-5thmetatarsal distance (12 to 18mm, p=0.047), and hindfoot moment arm (16 to 6mm, p=0.031). Other corrections had an impact on talar height (34 to 40mm, p=0.028), navicular height (26 to 30mm, p=0.031), cuboid height (p=0.021), and hindfoot alignment angle (17 to 7 degrees, p=0.003).Conclusion:When compared to procedures that only address bony changes in the foot, it is clear from this study that medial ligament repair plays a different, but significant, role in correction of flat foot deformity. Interestingly, the non-weight bearing and weight bearing results show that medial ligament reconstruction affects different aspects of the correction in these two distinct phases. This study serves to suggest that medial ligament reconstruction has a role in the correction of flat foot deformity that is not completely addressed in the more common procedures performed.

The Impact of Progressive Collapsing Foot Deformity on Foot &amp; Ankle Kinematics and Plantar Pressure During Simulated Gait

Category:Basic Sciences/Biologics; HindfootIntroduction/Purpose:Progressive collapsing foot deformity (PCFD) is a 3-dimensional pathology associated with insufficiency of the posterior tibial tendon (PTT), ligamentous failure, joint malalignment, and aberrant plantar force distribution. Existing knowledge of PCFD consists of static measurements, which provide information about the structure of the foot but none about its function. Cadaveric gait models provide an opportunity to measure motion both at the joints primarily affected in PCFD and the adjacent joints that are at risk for progressive subluxation and arthritis. This study sought to develop a flatfoot model for a robotic gait simulator and quantify gait kinematics and plantar pressure between normal and flatfoot conditions, which we hypothesized would be altered after the creation of a flatfoot deformity model.Methods:Cadaveric specimens were loaded on a 6-degree of freedom robotic gait simulator and the extrinsic tendons were attached to linear motors. Ground reaction forces and muscle forces were optimized utilizing an established iterative process. An 8-camera motion capture system was utilized to calculate joint kinematics using reflective markers attached by k-wires into bone. A plantar pressure mat attached to the force platform was used to calculate the center of pressure excursion index (CPEI) for each condition. The flatfoot model was created via sectioning of the spring ligament and medial talonavicular joint capsule followed by cyclic axial compression until 5-15° of talonavicular abduction was achieved in a static, loaded pose. Testing of the flatfoot state was then performed with inactivation of the PTT. Bias-corrected bootstrapped 95% confidence intervals were constructed from the repeated measures difference between flatfoot and normal conditions. Paired t-tests were used to compare the CPEI between conditions.Results:Twelve mid-tibia cadaveric specimens (mean age 73 years, 8 female) with no prior foot/ankle surgery were used. There were significant differences in kinematics between normal and PCFD conditions at the ankle, subtalar, and talonavicular joints (Figure). There was significantly increased ankle plantar flexion in flatfoot in the first 80% of stance phase. There was significantly greater subtalar eversion in flatfoot compared to normal from 10-90% of stance phase. Talonavicular abduction and eversion were also significantly greater in flatfoot from 10-100% of stance. The CPEI was significantly decreased in the flatfoot condition (Figure), indicating a medialization in center of pressure (p<0.0001).Conclusion:The results from this study support our hypothesis of altered kinematics and plantar pressure after flatfoot deformity creation and corroborate previous biomechanical studies of static alignment in PCFD. Increased talonavicular abduction and subtalar eversion are hallmarks of flatfoot deformity, and increased ankle plantarflexion may represent the plantarflexed position of the talus in PCFD. In addition, plantar pressure was significantly medialized with flatfoot deformity. These findings highlight the utility of the gait simulator as a tool for future study of PCFD, especially for analysis of deformity patterns and the specific effects of individual interventions.

Investigation of the relationship between the thickness of the plantar calcaneonavicular ligament and plantar fascia in patients with plantar fasciitis

BackgroundAlthough patients with plantar fasciitis show spring ligament laxity, the thickness of the spring ligament in patients with plantar fasciitis remains unclear. This study aimed to elucidate the morphological characteristics of the spring ligament in patients with plantar fasciitis based on an ultrasound imaging system (US). MethodsThirty feet of 30 patients (painful group) diagnosed with plantar fasciitis at our hospital and thirty feet of 30 healthy volunteers (healthy group) without plantar pain were investigated. The thicknesses of both the spring ligament and plantar fascia were assessed via a US statistical comparison of the spring ligament and plantar fascia thickness between the painful and healthy groups. This was performed using Welch’s t-test, and the significance level was set at p < 0.01. In addition, Pearson’s correlation coefficient was calculated to assess the correlation between the spring ligament and plantar fascia thickness in the two groups, and the significance level was set at p < 0.01. ResultsThe spring ligament thickness in the painful group was significantly lower than that in the healthy group (p < 0.001). The thickness of the plantar fascia in the painful group was significantly greater than that in the healthy group (p = 0.03). In addition, the correlation between the spring ligament and plantar fascia thickness was moderately negative (r = −0.42, p = 0.001). The thicker the plantar fascia in the subjects, the thinner was the spring ligament. ConclusionsThe thickness of the spring ligament in patients with plantar fasciitis decreased. The thinning of the spring ligament was negatively correlated with the thickening of the plantar fascia as per the US evaluation. Based on the spring ligament thinning determined via US evaluation, interventions such as insoles from an early stage could prevent the onset of plantar fasciitis.

The role of medial ligaments and tibialis posterior in stabilising the medial longitudinal foot arch: a cadaveric gait simulator study

BackgroundDebate exists whether adult acquired flatfoot deformity develops secondary to tibialis posterior (TibPost) tendon insufficiency, failure of the ligamentous structures, or a combination of both. AimThe aim of this study is to determine the contribution of the different medial ligaments in the development of acquired flatfoot pathology. Also to standardise cadaveric flatfoot models for biomechanical research and orthopaedic training. MethodsFive cadaveric feet were tested on a dynamic gait simulator. Following tests on the intact foot, the medial ligaments – fascia plantaris (FP), the spring ligament complex (SLC) and interosseous talocalcaneal ligament (ITCL) – were sectioned sequentially. Joint kinematics were analysed for each condition, with and without force applied to TibPost. ResultsEliminating TibPost resulted in higher internal rotation of the calcaneus following the sectioning of FP and SLC (d>1.28, p = 0.08), while sectioning ITCL resulted in higher external rotation without TibPost (d = 1.24, p = 0.07). Sequential ligament sectioning induced increased flattening of Meary’s angle. ConclusionFunction of TibPost and medial ligaments is not mutually distinctive. The role of ITCL should not be neglected in flatfoot pathology; it is vital to section this ligament to develop flatfoot in cadaveric models.

Anatomical variants of the medioplantar oblique ligament and inferoplantar longitudinal ligament: an MRI study

PurposeThe spring ligament complex (SL) is the chief static stabilizer of the medial longitudinal foot arch. The occurrence of normal anatomical variants may influence radiological diagnostics and surgical treatment. The aim of this study was to evaluate anatomical variants of the part of SL located inferior to the talar head (i-SL), medioplantar oblique ligament (MPO) and inferoplantar longitudinal ligament (IPL).MethodsWe included 220 MRI examinations of the ankle performed on a 3.0 T engine. Only patients with a normal SL were included. Two musculoskeletal radiologists assessed the examinations and Cohen’s kappa was used to assess agreement. Differences between groups were assessed using the chi-squared test; p < 0.05 was considered as significant. The final decision was made by consensus.ResultsMost commonly, i-SL was composed of the two ligaments IPL and MPO n = 167 (75.9%); in this group, bifid ligaments occurred in 19.2%, most commonly in the MPO. A branch to the os cuboideum was seen in n = 17 (10.2%). Three ligaments were seen in n = 52 (23.6%). In this group, bifid ligaments occurred in 13.5%; most commonly, the IPL was bifid and a branch to the os cuboideum was noted in n = 6 (11.5%). In one case, n = 1 (0.04%), we identified MPO, IPL and two accessory ligaments. No significant relationship was noted between the number of ligaments, the presence of bifid ligaments and side or gender (p > 0.05). Conclusion. More than two aligaments were seen in 24.1% of examined cases, the most common variant was the presence of MPO, IPL and one accessory ligament.

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

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. 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. 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. 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 IV, retrospective case series.

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

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. 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. 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. 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. 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 III, case-control study.