Kinematic changes in patients with double arthrodesis of the hindfoot for realignment of planovalgus deformity

Normal and malaligned talonavicular fusion alters cadaveric foot pressure and kinematics

Talonavicular (TN) fusion is a common treatment for TN arthritis or deformity correction. There is incongruous evidence regarding remaining motion at the talocalcaneal and calcaneocuboid joints after TN fusion. Additionally, the effects of a malaligned TN fusion are not well understood and alignment of the fusion may be important for overall foot integrity. This project assessed the kinematic and kinetic effects of neutral and malaligned TN fusions. Ten cadaveric feet were tested on a gait simulator in four conditions: unfused, fused in neutral, fused in varus, and fused in valgus. The fusions were simulated with external fixation hardware. An eight-camera motion analysis system and a 10-segment foot model generated kinematic data, and a pressure mat captured pressure data. Simulated TN fusion was achieved in eight feet. From unfused to fused-neutral, range of motion (ROM) was not eliminated in the adjacent joints, but the positions of the joints changed significantly throughout stance phase. Furthermore, the ROM increased at the tibiotalar joint. Plantar pressure and center of pressure shifted laterally with neutral fusion. The malalignments marginally affected the ROM but changed joint positions throughout stance phase. Pressure patterns were shifted laterally in varus malalignment and medially in valgus malalignment. The residual motion and the altered kinematics at the joints in the triple joint complex after TN fusion may subsequently increase the incidence of arthritis. Clinical significance: This study quantifies the effects of talonavicular fusion and malalignment on the other joints of the triple joint complex.

Double versus Triple Arthrodesis for Flatfoot Deformity: When, Why, and How?

Different types of arthrodesis for flatfoot deformity have a long history in foot and ankle surgery. Arthrodesis of the rearfoot can be a useful tool in helping correct deformity and maintaining that correction with good long-term results. Questions have risen recently however about the necessity of including the calcaneocuboid joint in the traditional rearfoot arthrodesis or triple arthrodesis. The double arthrodesis of the talonavicular and subtalar joints has grown in popularity and this review helps the reader choose with a review of the biomechanics, surgical approaches, fixation techniques and recent literature outcomes of both procedures.

Double and Triple Tarsal Fusions in the Severe Rigid Flatfoot Deformity

A flatfoot deformity is a multiplanar foot deformity characterized by forefoot abduction and supination and hindfoot valgus. With progressive pathology, a rigid deformity may develop. In the setting of a rigid deformity, the appropriate procedure to use is not without controversy. The extent of joints to involve in the arthrodesis depends on the ability to obtain a plantigrade foot. Both double and triple arthrodesis have been suggested. Care must be taken to avoid lateral column shortening and loss of foot reduction when fusing the CC joint. The concerns about lateral skin breakdown led some surgeons to describe a single medial incision for a triple or modified double arthrodesis. The necessity of bone grafting has been controversial. Implant selection is essential to achieve solid stabilization of the arthrodesis sites. To decrease the risk of overcorrection and malunion, the surgeon should be familiar with the hindfoot biomechanics and generate, based on the clinical examination and imaging, a meticulous preoperative plan to address and balance both the soft tissue and bony deformity.

Spare the Talonavicular Joint! The Role of Isolated Subtalar Joint Fusion in the Treatment of Progressive Collapsing Foot Deformity

Surgical management of progressive collapsing foot deformity continues to evolve. Previous studies have demonstrated that fusion of the talonavicular joint results in limited hindfoot motion and, therefore, may accelerate adjacent-joint arthrosis. Recent literature has supported using alternative arthrodesis constructs that spare the talonavicular joint, such as naviculocuneiform or isolated subtalar fusions, which may maintain some hindfoot motion through the talonavicular joint yet adequately address a patient's deformity. Concomitant reconstructive procedures may be used in addition to subtalar fusion to address severe deformities. Isolated subtalar fusions may be considered in cases of sinus tarsi or subfibular impingement deformities.

Consensus on Indications for Isolated Subtalar Joint Fusion and Naviculocuneiform Fusions for Progressive Collapsing Foot Deformity

RECOMMENDATION

Peritalar subluxation represents an important hindfoot component of progressive collapsing foot deformity, which can be associated with a breakdown of the medial longitudinal arch. It results in a complex 3-dimensional deformity with varying degrees of hindfoot valgus, forefoot abduction, and pronation. Loss of peritalar stability allows the talus to rotate and translate on the calcaneal and navicular bone surfaces, typically moving medially and anteriorly, which may result in sinus tarsi and subfibular impingement. The onset of degenerative disease can manifest with stiffening of the subtalar (ST) joint and subsequent fixed and possibly arthritic deformity. While ST joint fusion may permit repositioning and stabilization of the talus on top of the calcaneus, it may not fully correct forefoot abduction and it does not correct forefoot varus. Such varus may be addressed by a talonavicular (TN) fusion or a plantar flexion osteotomy of the first ray, but, if too pronounced, it may be more effectively corrected with a naviculocuneiform (NC) fusion. The NC joint has a curvature in the sagittal plane. Thus, preserving the shape of the joint is the key to permitting plantarflexion correction by rotating the midfoot along the debrided surfaces and to fix it. Intraoperatively, care must be also taken to not overcorrect the talocalcaneal angle in the horizontal plane during the ST fusion (eg, to exceed the external rotation of the talus and inadvertently put the midfoot in a supinated position). Such overcorrection can lead to lateral column overload with persistent lateral midfoot pain and discomfort. A contraindication for an isolated ST fusion may be a rupture of posterior tibial tendon because of the resultant loss of the internal rotation force at the TN joint. In these cases, a flexor digitorum longus tendon transfer is added to the procedure.

LEVEL OF EVIDENCE

Level V, consensus, expert opinion.

Comparative Study of Spring Ligament Reconstructions Using Either Hamstring Allograft or Synthetic Ligament Augmentation

BACKGROUND

Idiopathic flatfeet are usually caused by attenuation of the medial soft tissues rather than a lateral osseous deficiency. Debate continues on whether spring ligament attenuation or posterior tibial tendon (PTT) dysfunction is the initial driver for the deformity. Our comparative prospective study aimed to quantify the radiological and clinical outcomes of 2 techniques for spring ligament reconstruction using a hamstring graft or a synthetic ligament.

METHODS

Seventeen spring ligament reconstructions (SLRs) were performed in 17 patients using synthetic ligament augmentation and 16 SLRs were performed using hamstring allograft in 13 patients. Additional procedures such as gastrocnemius recession, PTT advancement, flexor digitorum longus transfer, and calcaneal osteotomy were performed as required. A minimum of 12 months of follow-up was available for all cases. Radiographic analysis was performed with standardized parameters.

RESULTS

Following SLR with synthetic ligament augmentation, all radiological parameters significantly improved (P < .05). Hamstring allograft SLR also demonstrated significantly improved radiographic parameters in all but Meary's line at final follow-up. At 12 months, patient outcome scores were significantly better in the synthetic ligament group.

CONCLUSION

Reconstruction of the spring ligament using either hamstring allograft or synthetic ligament augmentation provided significant improvements in radiological alignment; however, superior patient-reported outcomes were found in the synthetic ligament augmentation group.

LEVELS OF EVIDENCE

Level III, retrospective cohort study.

What is the Prognosis of Triple Arthrodesis in the Treatment of Adult Acquired Flatfoot Deformity (AAFD)?

Objective  The present study aims to evaluate the ability of triple arthrodesis in eliminating the main complaints presented by patients with adult acquired flatfoot deformity (AAFD): 1) disabling hindfoot pain; 2) major deformities, such as medial arch collapse, valgus, abduction, and supination. Methods  A total of 17 patients (20 feet) with advanced AAFD who underwent surgical correction by triple arthrodesis were evaluated after a mean follow-up period of 43 months (range: 18-84 months). The average age of the patients at surgery was 62 years old (range: 38-79 years old). The visual analogue scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score were used to assess the final results. Results  According to the VAS, the average residual pain was 3 points; the AOFAS hindfoot score points increased 23% after the surgery; and the correction of deformities was considered satisfactory in 10 out of 20 feet; partially satisfactory in 4 out of 20 feet; partially unsatisfactory in 5 out of 20 feet; and unsatisfactory in 1 out of 20 feet. Conclusion  Despite the high index of bone fusion after triple arthrodesis, which is the gold standard treatment in advanced AAFD, the incomplete correction of major deformities and the persistence of residual pain contributed to a high disappointment rate of the patients with the surgical results.

Pathological kinematic patterns of the tarsal complex in stage II adult-acquired flatfoot deformity

The in vivo kinematic characteristics of the tarsal joints during gait stance phase were still unclear in adult-acquired foot deformity (AAFD). This study included seven healthy subjects (14 feet) and 12 stage II AAFD patients (14 feet). The 3D models of tarsal bones were reconstructed based on CT scan. Each subject took standard gait on the single fluoroscopy system. Continuous lateral fluoroscopic images were collected. The key postures during the stance phase were selected. The 2D-3D registration technique was applied to explore the spatial motions of the tarsal joints in 6 degrees of freedom (DOF). During the whole stance phase, the AAFD talo-navicular joint (TNJ) exhibited ROM of 13 ± 6° in the sagittal plane while the normal subjects showed ROM of 7 ± 3° (p = 0.004). In AAFD, the subtalar joint (STJ) demonstrated 19 ± 8° and 7 ± 3° of motion in coronal and horizontal plane, respectively, while the normal subjects showed 14 ± 4°(p = 0.031) and 11 ± 3° (p = 0.014) of motion, respectively. Additionally STJ of AAFD patients showed significantly less dorsiflexion during the weight acceptance and showed significantly less external rotation both during the weight acceptance and single limb support of stance phase. In conclusion, for stage II AAFD patients, the talonavicular joint and the subtalar joint showed hypermobility in dorsi/planterflexion and inversion/eversion, respectively, during the gait stance phase while the internal/external rotation of the subtalar joint was reduced. The current study improves our understanding of the pathological kinematics of the tarsal complex in AAFD patients. Notice should be taken about these tarsal joints mobility in AAFD during clinical practice. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:477-482, 2019.

The influence of population characteristics and measurement system on barefoot plantar pressures: A systematic review and meta-regression analysis

BACKGROUND

The measurement of plantar pressure distributions during gait can provide insights into the effects of musculoskeletal disease on foot function. A range of hardware, software, and protocols are available for the collection of this type of data, with sometimes disparate and conflicting results reported between individual studies. In this systematic review and meta-regression analysis of dynamic regional peak pressures, we aimed to test if 1) the system used to obtain the pressure measurements and 2) the characteristics of the study populations had a significant effect on the results.

METHODS

A systematic review of the literature was undertaken to identify articles reporting regional peak plantar pressures during barefoot walking. A mixed-effects modeling approach was used to analyze the extracted data. Initially, the effect of the system used to collect the data was tested. Following this, the effect of participant characteristics on the results were analyzed, using moderators of cohort type (defined as the primary health characteristic of the participants), age, sex, and BMI.

RESULTS

115 participant groups were included in the analysis. Sufficient cohorts were available to test those that consisted of healthy individuals, and those with diabetes and diabetic neuropathy. Significant differences were found between results reported by studies using different pressure measurement systems in 8 of the 16 regions analyzed. The analysis of participant characteristics revealed a number of significant relationships between regional peak pressures and participant characteristics, including: BMI and midfoot plantar pressures; elevated forefoot pressures as a result of diabetic neuropathy; and sex-differences in regional loading patterns.

CONCLUSIONS

At the level of the literature, we confirmed significant effects of disease status, age, BMI, and sex on regional peak plantar pressures. Researchers and clinicians should be aware that measurements of peak plantar pressure variables obtained from different collection equipment are not directly comparable.

Overcorrected Flatfoot Reconstruction

The overcorrected flatfoot reconstruction is a less common but often difficult sequelae of surgical treatment of the adult acquired flatfoot deformity. Understanding the patient's symptoms and how they correlate to the procedures performed during the index surgery are paramount to determining the appropriate course of treatment. Patients' symptoms may resemble those seen in the cavovarus foot condition, often secondary to overlengthening of the lateral column or excessive displacement of the calcaneal tuberosity. Osteotomies of the calcaneus, midfoot, and often the first metatarsal may be sufficient to revise the overcorrection. However, hindfoot and/or midfoot arthrodesis may be required in more severe or rigid cases.

In Vivo Plantar Pressures in Adult-Acquired Flatfoot Compared to Control Using an Intraoperative Pedobarographic Device

BACKGROUND

Intraoperative pedobarography has the potential to aid surgical decisions, but no parameters exist to guide its use.

QUESTIONS/PURPOSES

This study compared supine plantar pressures between flatfoot patients and controls using a previously validated intraoperative pedobarographic device and examined associations between supine, walking, and standing plantar pressures.

METHODS

Ten preoperative patients with stage II adult-acquired flatfoot deformity (AAFD) were compared to ten healthy controls. Supine plantar pressures were assessed using the pedobarographic device. Standing and walking plantar pressures were assessed with an EMED-XT sensor array (Novel). Maximum force (MF) and peak pressure (PP) were calculated for nine anatomical foot regions adjusting for age and BMI.

RESULTS

No differences in plantar pressures were found between flatfoot patients and controls in the supine or standing positions. During walking, flatfoot patients had greater MF of the first, second, and third metatarsals (p ≤ 0.018) and greater PP of the first and second metatarsals than controls (p ≤ 0.010). Supine MF and PP were both strongly positively correlated with their respective pressure measurements for both standing and walking in multiple foot regions (p ≤ 0.05, all analyses). Correlations in the first metatarsal region were generally weak and not statistically significant.

CONCLUSION

This device did not show differences in supine plantar pressures of flatfoot patients and healthy subjects, highlighting the limitations of intraoperative devices in guiding flatfoot correction. The differences between flatfoot and controls during walking and the correlations between supine and walking conditions suggest that dynamic plantar pressures are a more useful parameter in guiding flatfoot reconstruction.

The Biology of Bone and Ligament Healing

This review describes the normal healing process for bone, ligaments, and tendons, including primary and secondary healing as well as bone-to-bone fusion. It depicts the important mediators and cell types involved in the inflammatory, reparative, and remodeling stages of each healing process. It also describes the main challenges for clinicians when trying to repair bone, ligaments, and tendons with a specific emphasis on Charcot neuropathy, fifth metatarsal fractures, arthrodesis, and tendon sheath and adhesions. Current treatment options and research areas are also reviewed.

Increased Failure Rate of Modified Double Arthrodesis Compared With Triple Arthrodesis for Rigid Pes Planovalgus

For rigid pes planovalgus deformities, modified double and triple arthrodeses have had high union rates and subjective outcomes reported. Increased rates of talonavicular nonunions after modified double arthrodesis have led to concern regarding this procedure. A retrospective medical record review was performed of patients who had undergone either a modified double (n = 9) or triple (n = 7) arthrodesis for stage 3 pes planovalgus deformity. Radiographs were reviewed for hindfoot alignment, bony union, and hardware failure. Data from questionnaires, including the Foot and Ankle Ability Measure and the Foot and Ankle Outcome Score, were obtained. No significant differences were found between the cohorts in terms of preoperative radiographic parameters or patient characteristics. The modified double arthrodesis cohort demonstrated a nonunion rate of 44% (4 of 9), but the triple arthrodesis cohort had a 0% (0 of 7) nonunion rate (p = .042). The Foot and Ankle Ability Measure activities of daily living, Foot and Ankle Outcome Score activities of daily living, and Foot and Ankle Outcome Score quality of life scores were significantly worse for the modified double arthrodesis than for the triple arthrodesis group. For patients with stage 3 pes planovalgus, modified double arthrodesis resulted in significantly greater rates of nonunion and incomplete union, with significantly inferior subjective outcome scores compared with triple arthrodesis for the same indication.

In vivo kinematic study of the tarsal joints complex based on fluoroscopic 3D-2D registration technique

The tarsal bones articulate with each other and demonstrate complicated kinematic characteristics. The in vivo motions of these tarsal joints during normal gait are still unclear. Seven healthy subjects were recruited and fourteen feet in total were tested in the current study. Three dimensional models of the tarsal bones were first created using CT scanning. Corresponding local 3D coordinate systems of each tarsal bone was subsequently established for 6DOF motion decompositions. The fluoroscopy system captured the lateral fluoroscopic images of the targeted tarsal region whilst the subject was walking. Seven key pose images during the stance phase were selected and 3D to 2D bone model registrations were performed on each image to determine joint positions. The 6DOF motions of each tarsal joint during gait were then obtained by connecting these positions together. The TNJ (talo-navicular joint) exhibited the largest ROMs (range of motion) on all rotational directions with 7.39±2.75°of dorsi/plantarflexion, 21.12±4.68°of inversion/eversion, and 16.11±4.44°of internal/external rotation. From heel strike to midstance, the TNJ, STJ (subtalar joint), and CCJ (calcaneao-cuboid joint) were associated with 5.97°, 5.04°, and 3.93°of dorsiflexion; 15.46°, 8.21°, and 5.82°of eversion; and 9.75°, 7.6°, and 4.99°of external rotation, respectively. Likewise, from midstance to heel off, the TNJ, STJ, and CCJ were associated with 6.39, 6.19°, and 4.47°of plantarflexion; 18.57°, 11.86°, and 6.32°of inversion and 13.95°, 9.66°, and 7.58°of internal rotation, respectively. In conclusion, among the tarsal joints, the TNJ exhibited the greatest rotational mobility. Synchronous and homodromous rotational motions were detected for TNJ, STJ, and CCJ during the stance phase.

Mid- to long-term outcome of 96 corrective hindfoot fusions in 84 patients with rigid flatfoot deformity

Talonavicular and subtalar joint fusion through a medial incision (modified triple arthrodesis) has become an increasingly popular technique for treating symptomatic flatfoot deformity caused by posterior tibial tendon dysfunction. The purpose of this study was to look at its clinical and radiological mid- to long-term outcomes, including the rates of recurrent flatfoot deformity, nonunion and avascular necrosis of the dome of the talus. A total of 84 patients (96 feet) with a symptomatic rigid flatfoot deformity caused by posterior tibial tendon dysfunction were treated using a modified triple arthrodesis. The mean age of the patients was 66 years (35 to 85) and the mean follow-up was 4.7 years (1 to 8.3). Both clinical and radiological outcomes were analysed retrospectively. In 86 of the 95 feet (90.5%) for which radiographs were available, there was no loss of correction at final follow-up. In all, 14 feet (14.7%) needed secondary surgery, six for nonunion, two for avascular necrosis, five for progression of the flatfoot deformity and tibiotalar arthritis and one because of symptomatic overcorrection. The mean American Orthopaedic Foot and Ankle Society Hindfoot score (AOFAS score) at final follow-up was 67 (between 16 and 100) and the mean visual analogue score for pain 2.4 points (between 0 and 10). In conclusion, modified triple arthrodesis provides reliable correction of deformity and a good clinical outcome at mid- to long-term follow-up, with nonunion as the most frequent complication. Avascular necrosis of the talus is a rare but serious complication of this technique.

Flexor digitorum longus transfer and medial displacement calcaneal osteotomy for the treatment of stage II posterior tibial tendon dysfunction: kinematic and functional results of fifty one feet

PURPOSE

Stage II posterior tibial tendon dysfunction (PTTD) can be treated by flexor digitorum longus (FDL) tendon transfer and medial displacement calcaneal osteotomy (MDCO). Numerous authors have studied the clinical and radiographic results of this procedure. However, little is known about the kinematic changes. Therefore, the purpose of this study was to assess plantar-pressure distribution in these patients.

METHODS

Seventy-three patients with PTTD stage II underwent FDL tendon transfer and MDCO. Plantar pressure distribution and American Orthopaedic Foot and Ankle Society (AOFAS) score were assessed 48 months after surgery. Pedobarographic parameters included lateral and medial force index of the gait line, peak pressure (PP), maximum force (MF), contact area (CA), contact time (CT) and force-time integral (FTI).

RESULTS

In the lesser-toe region, PP, MF, CT, FTI and CA were reduced and MF in the forefoot region was increased. These changes were statistically significant. We found statistically significant correlations between AOFAS score and loading parameters of the medial midfoot.

CONCLUSIONS

Study results reveal that FDL tendon transfer and MDCO leads to impaired function of the lesser toes during the stance phase. However, there seems to be a compensating increased load in the forefoot region.