Triple arthrodesis: a biomechanical evaluation of screw versus staple fixation

Patient Reported Outcomes Following Triple Arthrodesis for Adult Acquired Flat Foot Deformity: Minimum Two Year Follow Up

The aim of this study is to analyze patient-reported outcomes following this procedure as well as any demographics that may confer prognostic capability. A retrospective analysis was conducted of patients who underwent Triple Arthrodesis at our facility from 2014-2021. Patients were selected if they underwent an isolated triple arthrodesis. All cases included either a gastrocnemius recession versus a percutaneous tendo-achilles lengthening depending on the patient's Silverskiold examination. The electronic medical record was utilized to collect basic patient demographics, previous foot and ankle surgeries, hardware failures, additional procedures, and surgical complications. To evaluate outcomes, we compared patient reported outcomes measurement information system (PROMIS) survey scores with the general population and preoperative versus postoperative visual analog scale (VAS) scores. Foot function index (FFI) scores and scores were utilized as a validation tool for our results. A total of 132 patients met the criteria for our study with a total of 50 participants completing the PROMIS and FFI surveys. The average time point at which the outcomes were collected was 5.50 y postoperatively, ranging from 1.65 to 7.57 y. The average PROMIS physical function was 38.35, pain interference was 61.52, and depression was 49.82 for this population. The mean FFI scores were 58.56 for pain, 60.07 for disability, and 48.07 for activity limitation. There was a significant decrease in preoperative and postoperative VAS scores from 5.4 to 2.55 (p < .001). Three patients experienced wound complications related to decreased sensation. Our results indicated that only PROMIS depression scores were within one standard deviation of the population mean following a triple arthrodesis procedure. PROMIS physical function and pain interference were both outside of one standard deviation for the population.

A bending model for assessing relative stiffness and strength of orthopaedic fixation constructs

BACKGROUND

The purpose of this study is to develop a simple and reproducible bending model that is compatible with a wide range of orthopaedic fixation devices and 3D printed spacers.

METHODS

A robust 4-point bending model was constructed by securing sawbones blocks with different orthopaedic fixation device constructs. Stress strain curves derived from a fundamental mechanics model were used to assess the effect of bone density, type of hardware (staple vs intramedullary beam), the use of dynamic compression, orientation of staples (dorsal vs plantar), and the use of 3D printed titanium spacers.

FINDINGS

The high throughput 4-point bending model is simple enough that the methods can be easily repeated to assess a wide range of fixation methods, while complex enough to provide clinically relevant information.

INTERPRETATIONS

It is recommended that this model is used to assess a large initial set of fixation methods in direct and straightforward comparisons.

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.

Biomechanical comparison of nitinol compression staples versus fully threaded lag screws for talonavicular arthrodesis

Background

Talonavicular arthrodesis (TNA) is indicated for treatment of disorders that require immobilization of the hindfoot. Lag screw fixation is considered the reference standard technique for TNA. Despite consistently favorable clinical results using lag screw fixation, it is still associated with higher than desired complication and failure rates. Nitinol compression staples have been used for TNA based on potential advantages over lag screw fixation. However, functional biomechanical data comparing lag screw and nitinol compression staples for TNA are lacking. Therefore, the objective of this study was to compare nitinol compression staples to fully threaded lag screws for use in TNA with respect to their biomechanical properties during functional robotic testing.

Methods

TNA was performed on cadaveric feet (n = 12; 6 matched pairs) using either two nitinol compression staples (Arthrex, Naples, FL) or two fully threaded lag screws (Arthrex, Naples, FL) in random order, alternating between paired left and right feet. After instrumentation, specimens were mounting in a robotic testing system and loaded at 89 N/sec from 30 N to 445 N for 1 min. Then, continuous compressive load of 445 N was applied while cycling from 30° plantarflexion to 15° dorsiflexion for 10 cycles. Optical tracking markers attached to the talus and navicular bone tracked displacements. Translation data were recorded along the X, Y, Z planes. Rotation data were recorded for roll, pitch, and yaw. Significant (p < 0.05) differences between fixation methods were determined using paired t-Tests for each measured variable.

Results

There were no statistically significant differences between staples and screws for translation in X, Y, or Z planes. When comparing rotation (roll, pitch, and yaw), there were no statistically significant differences with the exception of increased roll rotation for staple fixation versus lag screw fixation during static compression testing (p = 0.009).

Conclusion

Based on comparison to the reference standard lag screw fixation for clinically relevant biomechanical properties measured during functional robotic testing of the hindfoot, nitinol compression staples are a viable option for talonavicular arthrodesis.

Anatomic Description of the Calcaneocuboid Joint: Implications for Staple Fixation

Understanding the anatomy of the calcaneocuboid (CCJ) remains essential when selecting staple fixation to optimize osseous purchase during rearfoot procedures. This anatomic study quantitatively describes the CCJ in relation to staple fixation sites. The calcaneus and cuboid from 10 cadavers were dissected. Widths at 5 mm and 10 mm increments away from the joint were measured in dorsal, midline, and plantar thirds of each bone. The widths between each position's 5 mm and 10 mm increments were compared using the Student's t test. The widths among the positions at both distances were compared using an ANOVA then post hoc testing. Statistical significance was set at p ≤ 0.05. The middle (23 ± 3 mm) and plantar third (18 ± 3 mm) of the calcaneus at the 10 mm interval was greater than the 5 mm interval (p = .04). At 5 mm distal to the CCJ, the dorsal third of the cuboid maintained a statistically significant greater width than the plantar third (p = .02). The 5 mm (p = .001) and 10 mm (p = .005) dorsal calcaneus widths as well as the 5 mm (p = .003) and 10 mm (p = .007) middle calcaneus widths were significantly greater than the plantar widths. This investigation supports the use of 20 mm staple 10 mm away from the CCJ in dorsal and midline orientations. Care should be taken when placing a plantar staple within 10 mm proximal to the CCJ as the legs may extend beyond the medial cortex compared to dorsal and midline placements.

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.

Double Versus Triple Arthrodesis Fusion Rates: A Systematic Review

Hindfoot arthrodesis is often required for end-staged deformities, such as posterior tibial tendon dysfunction, osteoarthritis, or rheumatoid arthritis. Although the need for hindfoot arthrodesis is generally accepted in severe deformities, there is a debate whether a double or triple arthrodesis should be performed. The aim of our systematic review is to review the fusion rates and mean time to fusion in double and triple arthrodesis. A total of 184 articles were identified using the keyword search through the database of articles published from 2005 to 2017. After review by 3 physicians, a total of 13 articles met the eligibility criteria. The reason for double or triple arthrodesis within the studies were posterior tibial tendon dysfunction, tarsal coalition, degenerative joint disease, osteoarthritis, rheumatoid arthritis, Charcot Marie Tooth, Multiple Sclerosis, Polio, neuromuscular disorder, cerebral palsy, acrodystrophic neuropathy, clubfoot, post-traumatic, and seronegative arthropathy (spondyloarthritis). Within these 13 studies, there were a total of 343 (6-95) subjects extremities operated on. The overall fusion rate for double arthrodesis was 91.75% (289/315) compared to 92.86% (26/28) triple arthrodesis fusion rate, p value .8370. The mean time to fusion for double arthrodesis was 17.96 ± 7.96 weeks compared to 16.70 ± 8.18 weeks for triple arthrodesis, p value = .8133. There are risks associated with triple arthrodesis including increased surgical times, lateral wound complications, residual deformity, surgical costs and peri-articular arthritis. Given the benefits of double arthrodesis over triple arthrodesis and the nearly equivalent fusion rates and time to fusion, double arthrodesis is an effective alternative to triple arthrodesis. The authors of this systematic review recommend double arthrodesis as the hindfoot fusion procedure of choice.

Staple-Plate Plus Screw vs Screw Alone in Talonavicular Arthrodesis: A Cadaveric Biomechanical Study

BACKGROUND

This study evaluated whether the addition of a nitinol staple-plate to a single cannulated screw increased the mechanical stability for a talonavicular fixation construct.

METHODS

Twenty matched pairs of cadaveric feet were randomized to fusion with either a single 5.5-mm cannulated screw or a screw and a plate with 2 screws and a slot with an 18-mm nitinol staple. After in situ fusion procedure, the talonavicular joint complex was dissected free and the ends were embedded in epoxy. The specimens were then cyclically loaded on a servohydraulic load frame (1000 cycles at 20 N, increasing at intervals of 20 N until failure), half of them for cantilever bending and the other half for torsion.

RESULTS

In the bending arm of the study, the staple-plate group showed significantly higher stiffness, failure load, and cycles to failure. In the torsion arm of the study, the staple-plate group also had higher cycles to failure, stiffness in external rotation, and torque to failure. No significant difference was noted in stiffness in internal rotation.

CONCLUSION

We found a significant increase in stability of the talonavicular joint when a nitinol staple-plate construct was placed to augment a single cannulated screw for the purpose of a talonavicular fusion.

CLINICAL RELEVANCE

This information may be helpful to surgeons in implant selection for this common arthrodesis procedure.

Triple Arthrodesis for Adult-Acquired Flatfoot Deformity

Originally described as a means to address fixed deformities or uncontrolled movement of the hindfoot observed in paralytic foot deformities, triple arthrodesis has evolved into a powerful procedure for the correction of a variety of foot deformities. Over the past decade, multiple advances have been made with respect to diagnostic imaging, fixation options, bone graft substitutes, and postoperative regimens. While this operation requires experience and skill to execute, when properly performed, it allows for correction of deformity and a plantigrade and ideally pain-free foot for ambulation. The purpose of this review is to highlight advances in the procedure and its application to the rigid planovalgus foot.

Level of Evidence:

Level V, review.

Comparison of cannulated screws versus compression staples for subtalar arthrodesis fixation

BACKGROUND

Different fixation techniques have been described in the literature for isolated subtalar arthrodesis (ISA). The purpose of this study was to compare the fusion rate and clinical outcome of ISA using cannulated compression screws or compression staples.

METHODS

Thirty-three patients (33 feet) underwent ISA using screw (17 feet) or staples (16 feet) fixation. Patients were followed for 42.7 ± 16.4 months (range, 24.5-84.3 months). The subtalar fusion was assessed radiographically and clinically. Clinical outcome measures included the visual analog scale (VAS) for pain and American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot score.

RESULTS

The average pain score decreased significantly from 6.4 ± 1.1 (range, 5-9) to 0.8 ± 1.3 (range, 0-4) (P < .001). In the screws group, the average AOFAS hindfoot score increased significantly from 54.6 ± 8.8 (range, 37-67) preoperatively to 86.1 ± 7.1 (range, 71-91) postoperatively (P < .001). In the staples group, the average AOFAS hindfoot score increased significantly from 53.4 ± 11.1 (range, 33-69) preoperatively to 83.4 ± 6.9 (range, 71-91) postoperatively (P < .001). The AOFAS hindfoot score was comparable in both groups (P = .149). Only the AOFAS hindfoot score function subgroup in the screw fixation was significantly higher than in the staples fixation group (P = .005). There were 4 cases of nonunion at the site of subtalar arthrodesis (2 from screws group, 2 from staples group). The complication rate was comparable in both groups.

CONCLUSION

The fusion rate was comparable in both groups, while the postoperative functional outcome was significantly better in the screw fixation group.

LEVEL OF EVIDENCE

Level III, retrospective comparative cohort study.

Comparison of two fixation methods for arthrodesis of the calcaneocuboid joint: a biomechanical study

BACKGROUND

The traditional fixation for a calcaneocuboid (CC) arthrodesis in triple arthrodesis is with a 6.5-mm cancellous screw. This procedure can be technically challenging. Fixation with a locking compression plate (LCP) may be easier to perform while achieving compression perpendicular to the fusion site. The purpose of this study was to compare the load to failure and the stiffness for each fixation method.

METHODS

Five matched-pair cadaver feet had an arthrodesis of the CC joint. For each matched pair, one was fixed with a screw and the other with an LCP. Surface bead markers were applied. Each specimen was then secured to a material testing machine through the calcaneus. The plantar surface of the cuboid faced the hydraulic ram to simulate weightbearing. A force was applied while the specimen was recorded with a high-resolution camera. The endpoint was maximal force at 2-mm separation between the calcaneus and cuboid measured along a horizontal axis.

RESULTS

The average force to failure and the average stiffness in the screw group were significantly less than the LCP group (P < .05). The screw construct failed in pullout from the cuboid; the LCP construct failed by plastic deformation of the plate.

CONCLUSION

Calcaneocuboid joint fixation with the LCP withstood a higher load until failure and demonstrated greater stiffness than with a 6.5-mm cancellous lag screw.

CLINICAL RELEVANCE

The use of LCP fixation can be considered as an alternative to oblique lag screw fixation for CC arthrodesis in a triple arthrodesis. It remains to be determined if LCP fixation leads to better clinical outcomes.

Single-incision lateral approach for triple arthrodesis

BACKGROUND

Triple arthrodesis is a powerful hindfoot corrective procedure involving fusion of the talonavicular (TN), calcaneocuboid (CC), and subtalar (ST) joints. A 2-incision approach, a single-incision medial triple arthrodesis, and a single-incision medial double arthrodesis are well described. We present a single-incision lateral approach to triple arthrodesis.

METHODS

We retrospectively reviewed 70 patients who underwent triple arthrodesis at our institution from 2007 to 2011. Patients had either double-incision (n = 33) or single-incision lateral (n = 37) triple arthrodesis. A single surgeon performed all procedures. The most common diagnosis was stage III planovalgus deformity. Deformity correction, union rate, time of surgery, complications, wound healing, reoperations, and pre- and postoperative visual analog scale (VAS) pain scores were analyzed for both groups.

RESULTS

There were no statistical differences in deformity correction, wound healing, complications, reoperations, or improvement in VAS pain scores. Operation time was significantly shorter in the single-incision lateral group (86 minutes vs 95 minutes, P = .0395). There was no difference in union rates with regard to the TN, ST, or CC joints. Five patients had radiographic nonunions of the CC joint between both groups.

CONCLUSIONS

This is the first study that presents outcomes of a single lateral approach for triple arthrodesis. The single-incision approach was faster. The low rate of symptomatic nonunions suggests that fusion of the CC joint may not be important in symptomatic relief or deformity correction.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Benchtop comparison of a novel dynamic compression screw to a standard cortical screw: compression integrity and gap size over time during simulated resorption

Literature reports the incidence of failed isolated foot and ankle fusions as up to 23%. A contributing factor is the natural bone resorption, which occurs resulting in loss of compression and gapping at the fusion site when standard static compression plates and screws are used. However, an innovative dynamic compression screw may provide lasting compression despite resorption. This benchtop study shows that the FxDEVICES spring-loaded dynamic POGO screw maintains more compression and more consistent compression rate during simulated resorption, as compared with a standard compression screw. The novel screw maintained much greater compression strength within the first millimeter of simulated resorption (13.57 vs 4.38 lb) and maintained greater compression strength at the test completion (1.14 vs 0 lb). The novel screw revealed a more consistent resorption rate over the duration of the simulation. Clinically, this may result in more stability and improved fusion rates.

Talonavicular joint fixation using augmenting naviculocalcaneal screw in modified double hindfoot arthrodesis

BACKGROUND

Triple arthrodesis and combined talonavicular/subtalar arthrodesis are procedures for hindfoot disorders. Achieving talonavicular joint fusion can be problematic. We hypothesized that talonavicular joint fixation bending stiffness could be increased by adding a fully-threaded screw inserted through the lateral navicular into the calcaneus.

MATERIALS AND METHODS

We used ten fresh-frozen cadaver hindfeet. The calcaneus and talus were immobilized, and talonavicular joint stripped of cartilage. Two partially-threaded 4.5-mm cannulated screws were placed across the talonavicular joint, one traversing the central third of the navicular and a second through the medial third of the navicular. We quantified talonavicular fixation bending stiffness and angulation in response to 4N-m bending moments applied to the navicular in four directions: plantar-to-dorsal (P-D), medial-to-lateral (M-L), dorsal-to-plantar (D-P), and lateral-to-medial (L-M). An augmenting fully-threaded 4.5 mm cannulated screw was then placed through the lateral third of the navicular into the calcaneus and the specimens retested.

RESULTS

The mean bending stiffness in each direction increased significantly after addition of the third screw. The stiffness increase in each direction was: P-D 92%, D-P 39%, L-M 108%, and M-L 56%. Correspondingly, mean talonavicular angulation significantly decreased in each direction: P-D 43%, D-P 28%, L-M 47%, and M-L 34%.

CONCLUSION

A third, fully-threaded screw from the lateral navicular into the calcaneus significantly increases talonavicular bending stiffness and decreases angulation.

CLINICAL RELEVANCE

The increased resistance to arthrodesis site motion afforded by the addition of a naviculocalcaneal screw may improve the likelihood of achieving successful talonavicular fusion in combined talonavicular/subtalar arthrodesis.

Principles of arthrodesis and advances in fixation for the adult acquired flatfoot

Arthrodesis continues to be the procedure of choice in treatment of the end-stage adult acquired flatfoot. Its goals are to provide pain relief, correct the deformity, and improve function and stability. A better understanding of anatomy and operative technique has led to significant refinements and advances in fixation. These devices have proved useful in arthrodesing and tenodesing procedures. The principles in achieving a sound arthrodesis and the various forms of fixation are discussed in detail.

Long-term results after a triple arthrodesis of the hindfoot: function and satisfaction in 36 patients

The long-term functional results of a triple arthrodesis of the hindfoot are not well known. In this retrospective cohort study we therefore investigated pain, function and alignment of the tibiotalar joint, patient satisfaction with the procedure and the prevalence of osteoarthritis (OA) of the tibiotalar joint after a median follow-up of six years. We also aimed to investigate whether there are patient and surgical characteristics associated with the outcome. Patients who underwent a triple arthrodesis for OA between January 1992 and July 2002 were invited to participate. A clinical examination was performed, the Ankle-Hindfoot Scale was completed, and radiographs were taken. Patient characteristics (e.g., age, gender and the indication for operation) and surgical characteristics (e.g., fixation material and use of bone graft) were collected. Sixty-one percent (22 patients) of the patients had a good total score on the Ankle-Hindfoot Scale. Nineteen patients (53%) were satisfied with the result of the operation and 47% of the patients had radiographic OA of the tibiotalar joint. In a univariate regression analysis, male gender and the score on the Ankle-Hindfoot Scale were significantly associated with radiographic OA. Patient satisfaction was significantly associated with a higher score on the Ankle-Hindfoot Scale and better dorsi-flexion of the ankle. Our study shows that 61% of the procedures in 36 patients with a triple arthrodesis for OA had a good score on the Ankle-Hindfoot Scale. Radiographic OA of the ankle was present in 47% of the cases and was not related to patient satisfaction. No patient characteristics or surgical characteristics were associated with the score on the Ankle-Hindfoot Scale.

Tarsal joint fusion using memory compression staples--a study of 10 cases

A prospective clinical study was undertaken to assess the effectiveness of Nickel-Titanium Memory compression staples for fusion of the intertarsal joints. Ten patients underwent procedures for fusion of various hindfoot and midfoot joints with the memory staples. The patients were evaluated regarding period of immobilization in cast and time to radiographic joint fusion. Arthrodesis was achieved in all patients. The average time to fusion was 7.8 weeks, with an average period of immobilization of 6.6 weeks. The early experience with the use of these staples in hindfoot and midfoot joint surgery is encouraging. We did not encounter any technical problems, and there is a suggestion that these implants may reduce the time to fusion.

[Severe foot deformities in adolescents and adults--techniques after Imhäuser, Lelièvre und Lambrinudi]

Severe contraction deformities of the foot, e.g. after trauma or spasticity, often lead to an inability to walk and can, in part, only be rectified by corrective bone osteotomy of the hind and middle foot. In this article, we discuss hind and middle foot osteotomies in cases of severe foot deformities in adolescents and adults. The surgical techniques of Lambrinudi, Imhäuser and Lelièvre will be considered. The surgical technique of Lambrinudi uses a triple arthrodesis between the talus, calcaneus and navicular bones, and the cuboid bone, in addition to the removal of a bone wedge from the talus for correction of the talipes equinus deformity. Severe contraction talipes calvus can be straightened and capable of loading using Imhäuser's technique with wedge osteotomy and arthrodesis in Chopart's joint. The planigrade position is achieved by the removal of a dorsolaterally based wedge from Chopart's joint. Using Lelièvre technique, severe contraction club foot with hind foot varus can be treated with a wedge from Chopart's joint and the talocalcaneal joint with arthrodesis. For stabilization, a compression clamp system is used. The advantages of the system used by us is that, in comparison with other systems, it can also be used for sclerotic bones as the shank is not hammered in but is introduced after boring. Using the compression clamp system, good stability and a high rate of osseous blood circulation can be achieved using osteotomies and arthrodeses. The aim of surgery is, in all cases, the correction of the deformity, functional improvement and the elimination of pressure points and pain.

Hindfoot arthrodesis for the adult acquired flat foot

This article reviews hindfoot arthrodesis for the adult acquired flat foot. Discussion of triple arthrodesis, triple arthrodesis with the addition of a lateral column lengthening procedure, triple arthrodesis with the addition of a plantar flexion first metatarsoncuneiform arthrodesis, and an isolated subtalar arthrodesis are discussed. The indications, surgical techniques, outcome studies, and complications are addressed.

Biomechanical evaluation of two different screw positions for fusion of the calcaneocuboid joint

In triple arthrodesis performed for severe deformity and neuroarthropathy in poorly compliant patients with osteoporotic bone, fixation of the arthrodesis is critical. We biomechanically tested an alternative means of stabilization for calcaneocuboid fusions. In seven matched pairs of fresh-frozen cadaver feet, we removed the soft tissue from around the calcaneocuboid joint, except for the capsule, and we did not resect the articular cartilage. One joint of each pair was fixed with an oblique standard screw, and the contralateral joint was stabilized with an axial screw placed perpendicularly to the joint surface. Testing on an MTS Mini Bionix Test Frame (MTS Systems Corp., Eden Prairie, MN) demonstrated that the axial screw provided significantly higher initial stiffness and maximum load to failure. We concluded that an axial screw provided better fixation of the calcaneocuboid joint.