Overview of subtalar arthrodesis techniques: options, pitfalls and solutions

Parallel versus Angulated Screw Configuration in Subtalar Arthrodesis for Posttraumatic Arthritis

Background

To compare radiographic union and clinical outcomes between parallel and angulated screw configurations (SCs) for patients undergoing subtalar arthrodesis due to posttraumatic subtalar arthritis (PSA) after displaced intra-articular calcaneal fractures.

Methods

This study retrospectively reviewed 140 consecutive PSA cases from March 2011 to November 2021 (parallel SC: group 1, n = 80; angulated SC: group 2, n = 60). Radiographic union, Foot and Ankle Outcome Score (FAOS), and visual analog scale (VAS) scores were among the outcome assessments. Six months after surgery, nonunion was confirmed based on plain radiographs, clinical evaluation, and computed tomography.

Results

Groups 1 and 2 included 14 (17.5%) and 3 (5.0%) nonunion cases, respectively (p = 0.035). There was no significant difference in preoperative FAOS and VAS scores between the groups. However, group 2 had significantly better clinical outcomes in 2 of the 5 FAOS domains (sports and quality of life), as well as VAS scores at 3 and 6 months postoperatively and at the final follow-up (p < 0.05).

Conclusions

Using the angulated SC for PSA had a lower nonunion rate and superior clinical outcomes than the parallel SC. Obtaining better radiological and clinical outcomes when using the angulated SC, rather than the parallel SC, would be advantageous.

Effect of Arthrodesis Device Type and Trajectory on Subtalar Joint Compression

The use of subtalar arthrodesis procedures has been widely implemented to relieve hindfoot issues after failure of conservative treatments; however, fusion failures persist in some patients with certain risk factors. Currently, surgeons utilize cannulated screws in these arthrodesis procedures to immobilize the subtalar joint. Recent clinical studies have demonstrated improved fusion outcomes in at-risk patients using sustained dynamic compression devices in the tibiotalocalcaneal complex. These devices utilize pseudoelastic nitinol which enables sustained dynamic compression when faced with postoperative bone resorption, joint settling, and bone relaxation. While the clinical success of these devices has been established in the tibiotalocalcaneal complex, the ability of sustained dynamic compression devices to apply joint compression in the subtalar joint has not been quantified. As such, the goals of this study were to (1) compare the ability of static compression devices and sustained dynamic compression devices to apply joint compression and (2) assess the impact of device trajectory on joint compression. A custom mechanical testing fixture was utilized to test the compression applied across the subtalar joint by one sustained dynamic compression device (in anterior and posterior trajectories) as compared to 2 cannulated screws (in both parallel and diverging trajectories). Testing revealed the sustained dynamic compression devices generated 53% greater compression as compared to the static compression devices, despite single versus dual device usage, respectively. Additionally, both types of devices applied joint compression forces in an insertion trajectory-independent manner. These data illustrate the ability of a single SDC device to maintain significantly improved joint compressive forces as compared to 2 static cannulated screws, regardless of insertion trajectory. These SDC devices may be of particular interest for at-risk patients or in revision cases.

Effect of Simulated Bone Resorption on the Biomechanical Performance of Intramedullary Devices for Foot and Ankle Arthrodesis

Midfoot and subtalar arthrodesis surgeries are performed to correct foot deformities and relieve arthritic pain. These procedures often employ intramedullary (IM) devices. The aim of the present study was to evaluate the biomechanical performance of a sustained dynamic compression (SDC) IM device compared to mechanically static devices in withstanding the effects of simulated bone resorption. Mechanically static and SDC IM devices were implanted in simulated bone blocks (n = 5/device). Compressive loads were measured with a custom-made mechanism to simulate bone resorption. The construct bending stiffness was determined from a 4-point bend test. Resorption was simulated by cutting a 1 mm or 2 mm gap in the midpoint of each construct and repeating the loading (n = 6/device). Initial compressive loads after device insertion were greater in the SDC IM devices when compared to the static devices (p < .01). The SDC device was able to sustain compression from 2 mm to 5.5 mm of simulated resorption depending upon device length, while the static devices lost compression within 1 mm of simulated resorption regardless of implant length (p < .001). In the 4-point bend test, the SDC device maintained its bending stiffness during simulated resorption whereas the static device displayed a significant loss in bending stiffness after 1 mm of simulated resorption (p < .001). The SDC device exhibited a significantly higher bending stiffness than the static device (p < .001). The SDC IM device demonstrated superior biomechanical performance during simulated resorption compared to static devices (p < .001). In conclusion, the ability of SDC IM devices to maintain construct stability and sustain compression across the fusion site while adapting to bone resorption may lead to greater fusion rates and overall quicker times to fusion than static IM devices. Surgeons who perform midfoot and subtalar arthrodesis procedures should be aware of a device's ability to sustain compression, especially in cases where bone resorption and joint settling are prevalent postoperatively.

Factors associated with nonunion of the posttraumatic subtalar arthrodesis after displaced intra-articular calcaneal fractures

BACKGROUND

This study investigated the incidence of and risk factors for nonunion in patients with posttraumatic subtalar arthrodesis (SA).

METHODS

We retrospectively reviewed 165 posttraumatic SA cases. Nonunion was diagnosed at 6 months after surgery based on the findings of clinical evaluations, plain radiographs, and CT scans. Patient-specific factors and surgeon-specific factors were evaluated as potential risk factors.

RESULTS

The overall nonunion rate was 13.3 % (22 of 165 cases). In the final multivariate logistic regression analysis, smoking (odds ratio [OR] = 3.64; 95 % confidence interval [CI] = 1.23-10.75), parallel screw configuration (OR = 5.70; 95 % CI = 1.62-20.06), and freeze dried iliac crest (OR = 9.16; 95 % CI = 2.28-36.79) were demonstrated as risk factors for nonunion of posttraumatic SA.

CONCLUSION

Patients with a history of smoking, parallel screw configuration fixation, and those who received freeze dried iliac crest as an interpositional graft, had a significantly higher rate of nonunion.

Lateral endoscopy of the sinus tarsi: Anatomy, technique and current indications

Numerous pathologies are reported in the lateral mid- and hind-foot. Access to the sinus tarsi is difficult, making lateral endoscopy the preferred approach. The present technical note describes the anatomy, technique and current indications for lateral endoscopy of the sinus tarsi.

Inconclusive evidence that arthroscopic techniques yield better outcomes than open techniques for subtalar arthrodesis-A systematic review

IMPORTANCE

Open in situ subtalar arthrodesis (ISTA) has been a standard procedure for treating subtalar arthritis for varied etiologies with good outcomes. There has been a paradigm shift from ISTA to arthroscopic subtalar arthrodesis (ASTA) over the past two decades due to increase in number of surgeons performing arthroscopy worldwide. However, there is only limited evidence in the existing literature to substantiate the benefit of this change with regards to patient benefit. To our knowledge, there are also no systematic reviews comparing the results of the two techniques for subtalar arthrodesis (STA).

AIM

Our systematic review aims to determine the superior technique for performing STA by comparing the outcomes, union rates, and complications between open and arthroscopic approach for in situ STA. We hypothesised that both procedures would have similar outcomes, union rates, time to union, and complication rate for in-situ STA.

EVIDENCE REVIEW

Three databases, MEDLINE/PubMed, the Cochrane Library, and Google Scholar, were searched using predefined inclusion and exclusion criteria to compare the two procedures. Risk of bias assessment was done using The Risk of Bias in Non-randomised Studies of Interventions (ROBINS-I) tool for assessing the risk of bias in the included studies. Weighted mean averages were computed for all parameters and tabulated separately for ASTA and ISTA.

FINDINGS

We included a total of 22 studies with a total of 978 (ASTA-310, ISTA-668) patients in the review. The most common indication for both techniques was post traumatic subtalar arthritis due to malunited calcaneal fracture in both groups (54.5%). The American Orthopaedic Foot & Ankle Society score was better in the ASTA group with a weighted average improvement of 43.4, while the weighted average improvement was 31.1 in the ISTA group, respectively. Patients undergoing ASTA had a weighted average union rate of 95.5% (standard deviation [SD]-3.6) with a weighted average time to union of 12.2 weeks (SD-2.4) while the ISTA group reported 90.7% (SD-6) union rate with a weighted average time to union of 15.5 weeks (SD-8.4). The weighted overall average complication rate was 13.1% (SD-8.9) in ASTA group and 20.3% (SD-16.2) in the ISTA group with hardware-related complications being the most common in both the groups.

CONCLUSION

From the existing literature, our review suggests that both ASTA and ISTA techniques are effective procedures for STA. However, there is no conclusive evidence to recommend one technique over another. High quality randomised studies may be further required to clearly define the superiority of one technique over another LEVEL OF EVIDENCE: level III.

Radiographic Outcomes of Isolated Subtalar Joint Arthrodesis With Varying Fixation Technique

Subtalar joint (STJ) arthrodesis is a well-established and accepted surgical procedure utilized for the treatment of various hindfoot conditions including primary or posttraumatic subtalar osteoarthritis, hindfoot valgus deformity, hindfoot varus deformity, complex acute calcaneal fracture, symptomatic residual congenital deformity, tarsal coalition, and other conditions causing pain and deformity about the hindfoot. Union rates associated with isolated subtalar joint arthrodesis are generally thought to be favorable, though reports have varied significantly, with non-union rates ranging from 0 to 46%. Various fixation constructs have been recommended for STJ arthrodesis. The purpose of this study was to compare radiographic union in a 2-screw fixation technique to a 3-screw fixation technique for patients undergoing primary isolated STJ arthrodesis. To this end, we retrospectively reviewed 54 patients; 26 in the 2-screw group and 28 in the 3-screw group. We found the median time to radiographic union to be 9 weeks for the 2-screw cohort and 7 weeks for the 3-screw cohort. Additionally, we found that the 2-screw fixation cohort had a radiographic non-union rate of 26.9% while the 3-screw cohort had no non-unions. We conclude that the use of a 3-screw construct for isolated STJ arthrodesis has a lower non-union rate and time to union when compared to the traditional 2-screw construct and should be considered as a fixation option for STJ arthrodesis.

Postoperative Ankle Imaging, 2022

Postoperative ankle imaging requires knowledge of the underlying surgical techniques, the usefulness of various imaging modalities, as well as an appreciation for the desired clinical outcomes. Surgical procedures discussed in this article are tibiotalar fracture fixation, tibiotalar, subtalar, and tibiotalocalcaneal arthrodesis, total ankle arthroplasty, talar osteochondral lesion repair and grafting, lateral ligamentous repair and reconstruction, and peroneal and Achilles tendon repair and reconstruction. Imaging can play a vital role in determining if the expected outcome has been achieved and identifying complications, with particular emphasis placed on the use of radiographs, computed tomography (including weight-bearing), magnetic resonance imaging, and ultrasonography.

Persistent Pain After Hindfoot Fusion

One of the most challenging problems facing orthopedic surgeons is persistent pain after surgery and certainly is just as frustrating following hindfoot fusion. The hindfoot joints consist of the subtalar, talonavicular, and calcaneocuboid (CC) joints. These joints are commonly fused for degenerative changes, deformity correction, inflammatory or neuropathic arthropathy, tarsal coalition, or primarily after trauma. Goals of hindfoot fusion are a painless plantigrade foot capable of fitting in shoes without orthotics or a brace. Many believe that deformity correction is achievable without inclusion of the CC joint. Managing patient expectations is important when counseling a patient especially regarding potential complications.

Arthroscopic Subtalar Joint Arthrodesis: Topical Review

BACKGROUND

Advances in foot and ankle arthroscopy over the last 2 decades have allowed for subtalar joint arthrodesis to be performed arthroscopically. The potential advantages of the arthroscopic technique include higher fusion rates, lower complications, reduced perioperative morbidity, and accelerated rehabilitation. Arthroscopic arthrodesis may, however, not be appropriate in the setting of complex deformity correction or the need for other open procedures.

METHODS

Surgical techniques of arthroscopic subtalar joint arthrodesis are described. Outcomes and complications associated with these procedures are presented, based on a comprehensive literature review. Thirteen Level IV studies of moderate quality were included.

RESULTS AND CONCLUSION

Excellent arthrodesis union rates were achieved (average 96%, range 86%-100%), at a weighted average union time of 8.8 weeks (95% confidence interval 7.9-9.7). The overall complication rate was 21% (87/415 feet; range 10%-36.4%). Metal irritation was the most common complication (11.2%), followed by nerve injury (4.2%) and infection (0.9%). Similar fusion rates have been reported when comparing arthroscopic and open arthrodesis. Complication rates are also similar, excerpt for infection, which may be lower with arthroscopy. Three different approaches were used to access the subtalar joint with similar union and complication rates. There was no evidence that the use of bone graft or more than 1 screw improved outcomes. The superiority of arthroscopic subtalar fusion over open techniques cannot be demonstrated by the available studies.

LEVEL OF EVIDENCE

Level IV, case series.

Outcomes of Posterior Arthroscopic Subtalar Arthrodesis for Medial Facet Talocalcaneal Coalition

BACKGROUND

Medial facet talocalcaneal coalition can be a painful condition. This study aimed to determine clinical and radiographic outcomes of posterior arthroscopic subtalar arthrodesis (PASTA) for adult patients presenting with symptomatic medial facet talocalcaneal coalition and normal hindfoot alignment, with a minimal follow-up of 18 months.

METHODS

Between June 2017 and July 2019, this procedure was performed on 8 feet (8 patients; mean age, 55 [42-70] years; mean BMI, 29.8 [24.4-45.0] kg/m²). Clinical assessment was performed using Visual Analog Scale for Pain (VAS-P), Foot and Ankle Outcome Score (FAOS) and the 36-Item Short-Form Health Survey (SF-36). Patient satisfaction was assessed at the last available follow-up as "very satisfied", "satisfied" or "unsatisfied". Radiographic analysis was performed using plain radiography, computed tomography (CT) scan and magnetic resonance imaging (MRI). The primary outcome was to determine both clinical and radiographic outcomes.

RESULTS

The mean follow-up was 25.1 (18.2-34.2) months. The authors found statistically significant improvement on all clinical scores (VASP-P, FAOS and SF-36). They registered 6 "very satisfied" patients, 2 "satisfied" patients and no "unsatisfied" patient. Fusion of the subtalar joint was observed in all patients by 12 weeks and in 5 of them as soon as 8 weeks postoperatively (mean, 9.5 [8-12] weeks). There were no cases of delayed fusion or nonunion of the subtalar joint, superficial or deep infection, neurovascular damage, thromboembolic event, screw breakage, need for hardware removal or revision surgery.

CONCLUSION

This study found that PASTA is a safe and reliable technique for adult patients presenting with symptomatic medial facet talocalcaneal coalition and normal hindfoot alignment, demonstrating and maintaining clinical improvement at an average follow-up of 2 years.

LEVEL OF EVIDENCE

Level IV, case series.

Subtalar arthrodesis using a single compression screw: a comparison of results between anterograde and retrograde screwing

INTRODUCTION

The primary objective of this study was to compare the radiological and clinical results of anterograde and retrograde screwing in subtalar arthrodesis using a single compression screw. The secondary objective was to evaluate the subjective results and consolidation of this procedure. The hypotheses were that isolated screw fixation was sufficient to achieve good consolidation and that there was no difference between the two techniques with a similar rate of bone fusion.

METHODS

This is a monocentric, retrospective, radio-clinical study based on 99 patients (101 feet), 58 males and 41 females, with an average age of 64 years. The main aetiology was post-traumatic osteoarthritis, which represented 51% of cases. Two groups were formed: group A (52 feet) consisting of fixed arthrodesis with ascending (retrograde) screwing and group D (49 feet) consisting of fixed arthrodesis with descending (anterograde) screwing. The two groups were statistically comparable in terms of demographic data as well as aetiologies and comorbidities. Arthrodeses which were not fused at 6 months were reassessed at one year and in the event of any radio-clinical doubt regarding consolidation, an additional CT scan was prescribed. Average post-operative follow-up was 11 ± 5 years (2-27 years).

RESULTS

Ninety-two arthrodeses (93%) were fused at one year and 9 were considered to be in non-union, 5 (9.8%) in group A, and 4 (8.3%) in group D. We recorded 30 complications, 22 of which were due to a conflict with the screw head, 18 (34.5%) in group A and 4 (8.3%) in group D (p = 0.03). Conflict between the screw head and the heel led to the removal of the screw after consolidation of the arthrodesis. The clinical results were evaluated using Odom's criteria. Nine per cent of patients described their results as excellent, 29% as good, 51% as satisfactory and 11% found the result to be poor.

CONCLUSION

The fusion rate for isolated compression screw arthrodesis is good, and there is no difference between anterograde and retrograde screws. However, the discomfort caused by the screw head being insufficiently embedded in the retrograde group led to a non-negligible number of additional surgeries to remove the screw.

Subtalar joint preparation using the Two Portal posterior arthroscopic technique versus the sinus tarsi Open approach: A cadaver study

BACKGROUND

Subtalar fusion is the treatment of choice for subtalar arthritis when conservative management fails. The procedure can be performed arthroscopically or through the open lateral sinus tarsi (LST) approach. The arthroscopic technique is less invasive and is associated with rapid recovery, but it is more technically challenging. One of the most important aspects of fusion is adequate preparation of the joint via denudation of articular cartilage. This study compares the efficacy of subtalar joint preparation between the lateral sinus tarsi approach and the posterior two-portal arthroscopic technique using cadaveric specimens.

MATERIALS AND METHODS

Nineteen below-knee fresh-frozen cadaver specimens were used. The subtalar joints of nine specimens were prepared through the LST approach, while ten were prepared arthroscopically. After preparation, all ankles were dissected at the subtalar joint and photographs were taken of the posterior facets of the calcaneus and talus. Total and prepared surface areas of the articular surfaces for both approaches were measured using ImageJ software and compared.

RESULTS

The LST technique resulted in significantly greater percent preparation of the posterior facet of the calcaneus, as well as of the subtalar joint as a whole. Overall, 92.3% of the subtalar joint surfaces (talus and calcaneus combined) were prepared using the LST technique, compared to 80.4% using the arthroscopic technique (p = 0.010). The posterior facet of the calcaneus was 94.0% prepared using the open technique, while only 78.6% prepared using the arthroscopic technique (p = 0.005).

CONCLUSION

The LST approach for subtalar arthrodesis provides superior articular preparation compared to the two-portal posterior arthroscopic technique. Given that joint preparation is a critical component of fusion, maximizing prepared surface area is desirable and the open approach may be more efficacious for fusion. When using the arthroscopic approach, it may be advisable to use an accessory portal if there is poor visualization or limited access to the joint space secondary to severe arthritis.

LEVEL OF EVIDENCE

V.

Arthroscopic triple arthrodesis for the patient with rheumatoid arthritis; a case report

We treated a 60 - year - old man with pes planovalgus due to rheumatoid arthritis. He had been suffering from left foot pain with swelling. Despite drug therapy, his foot pain and deformity had got worsen. Taking into consideration his skin and bone quality, arthroscopic triple arthrodesis was performed. To access the subtalar joint, 2 portals were applied at the sinus tarsi, and decortication was performed. For calcaneocuboid joint, 1.5 cm portal was applied along with joint line at calcaneocuboid joint. Calcaneocuboid joint was fully decorticated, then, 1.5 cm portal was applied at the joint line of talonavicular joint in parallel. Synovectomy and decortication under arthroscopy were performed. Once each joint was sufficiently prepared, it was fixed using screws via a percutaneous stab incision with an autologous bone graft from the iliac crest to the calcaneocuboid and talonavicular joint. At 12 weeks postoperatively, bone union was confirmed. The Japan Society for Surgery of the Foot (JSSF) RA foot and ankle scale had improved from the postoperative value of 38 points to a postoperative score of 86 points at one year. Plain radiographs showed that good alignment of the patient's hindfoot was maintained. We found that arthroscopic approach was able to achieve satisfactory outcome and minimise soft tissue trauma in a compromised patient.

Comparison of different bone graft with arthroscopy-assisted arthrodesis for the treatment of traumatic arthritis of the subtalar joint

AIM OF THE STUDY

To compare the clinical outcomes of traumatic arthritis of the subtalar joint treated by arthroscopy-assisted arthrodesis with autologous bone graft, allogenous bone graft, artifical bone graft, and no bone graft .

METHODS

Sixty-two patients (64 ft) with traumatic arthritis of subtalar joint were randomly divided into four groups. The cases treated with arthroscopy-assisted arthrodesis were analyzed retrospectively. The mean follow-up time was about 22 months (18-28 months) in each group. Clinical outcomes were assessed by the American Orthopaedic Foot and Ankle Society (AOFAS) score, Visual Analog Scale (VAS), and radiographic examination. The post-operative complications in each group were recorded respectively.

RESULTS

All operations were successful, without incision complications. The subtalar joint obtained full osseous fusion in each group. The average time of osseous fusion was about 12 weeks. There was no significant difference in the fusion time with each group (P = 0.991). The AOFAS and VAS scores in each group were improved significantly in the pre-operative vs post-operative evaluation (all P < 0.01). The average operation time in autologous bone graft group was 74.56 ± 11.45 min which significantly different from that of other groups(P < 0.01).

CONCLUSION

Similar clinical outcomes were achieved among each type of bone graft. Therefore, which types of bone graft or not may be not the most important for arthroscopy-assisted subtalar arthrodesis.

How many screws are necessary for subtalar fusion? A retrospective study

BACKGROUND

Biomechanical studies have shown a higher compressive force and higher torsional stiffness for fixation with three screws compared to two screws. However, clinical data to compare these fixation techniques is still lacking.

METHODS

A retrospective analysis of 113 patients was performed, who underwent isolated subtalar fusion between January 2006 and April 2018.

RESULTS

Revision arthrodesis was required in 8% (n=6/36) for 3-screw-fixation and 38% (n=35/77) for 2-screw-fixation. For 3-screw-fixation, non-union, was observed in 14% (n=5/36) compared to 35% (n=27/77) in 2-screw fixation. Non-union (p=.025) and revision arthrodesis (p=.034) were significantly more frequent in patients with 2 screws. A body mass index ≥30kg/m² (p=.04, OR=2.6,95%CI:1.1-6.3), prior ankle-fusion (p=.017,OR=4.4,95%CI:1.3-14.5) and diabetes mellitus (p=.04,OR=4.9,95%CI:1.1-17.8) were associated with a higher rate of revision arthrodesis.

CONCLUSIONS

Our findings suggest that successful subtalar fusion is more reliably achieved with use of three screws. However, future prospective studies will be necessary to further specify this recommendation.

Subtalar Fusion Preparation: What Are We Really Doing? A Cadaver Study

Introduction. The open, lateral sinus tarsi approach is the most commonly used technique for subtalar arthrodesis. In this cadaver study, we measured the maximum joint surface area that could be denuded of cartilage and subchondral bone through this approach. Methods. Nine fresh frozen above-knee specimens were used. The subtalar joint was accessed through a lateral incision from the fibular malleolus distally over the sinus tarsi area to the level of the calcaneocuboid joint. Cartilage was removed from the anterior, middle, and posterior facets of the calcaneus and talus using an osteotome and/or curette. ImageJ was used to calculate the surface areas of undenuded cartilage. Results. No specimens were 100% denuded of cartilage on all 6 measured surfaces. The greatest percentages of unprepared surface area remained on the middle facet of the talus (18.66%) and the middle facet of the calcaneus (14.51%). The anterior facet of the talus was 100% denuded in 6 specimens, while the middle and posterior facets were 100% denuded in 3 specimens. The anterior facet of the calcaneus was also 100% denuded in 6 specimens, while the middle and posterior facets were 100% denuded in 3 and 4 specimens, respectively. The average total unprepared surface area per specimen was 8.67%. Conclusion. The lateral sinus tarsi approach provides adequate denudation of cartilage of the subtalar joint in most cases. Total percentage of unprepared joint surface may range from approximately 2% to 18%. Future clinical studies are warranted to assess whether this technique results in optimal union rates. Levels of Evidence:V, Cadaveric Study.

Biomechanical comparison of plantar-to-dorsal and dorsal-to-plantar screw fixation strength for subtalar arthrodesis

Objective

To compare screw fixation strength for subtalar arthrodesis.

Methods

Eight matched pairs of cadaver feet underwent subtalar joint arthrodesis with two 7.3mm cannulated screws. Randomization was used to assign screw orientation, such that one foot in each pair was assigned dorsal to plantar screw orientation (DP Group), and the other foot, plantar to dorsal orientation (PD Group). Standard surgical technique with fluoroscopy was used for each approach. Following fixation, each specimen was loaded to failure with a Bionix ^® 858 MTS device, applying a downward axial force at a distance to create torque. Torque to failure was compared between DP and PD Groups using Student’s t test, with p=0.05 used to determine statistical significance.

Results

Statistical analysis demonstrated that the mean torque to failure slightly favored the DP Group (37.3Nm) to the PD Group (32.2Nm). However, the difference between the two groups was not statistically significant (p=0.55).

Conclusion

In subtalar arthrodesis, there is no significant difference in construct strength between dorsal-to-plantar and plantar-to-dorsal screw orientation. The approach chosen by the surgeon should be based on factors other than the biomechanical strength of the screw orientation.

Subtalar fusion and exostectomy in calcaneus malunion: How we do it

Calcaneus malunion is a common sequela to calcaneal fractures and is a cause of pain and discomfort. Multiple approaches have been described to address the subtalar joint and the lateral wall. Type 2 malunion is the most commonly encountered problem, and is usually addressed by the sinus tarsi approach. This has some limitations, as exposure for lateral wall excision beneath the peroneal tendons maybe a problem. We have slightly modified the sinus tarsi approach by a more horizontal skin incision, which may even be extended proximally by 1-2 cm; this allows access to the lateral wall on either side of the peroneal tendons. The approach is described in detail.

Minimally invasive subtalar arthrodesis for traumatic subtalar arthritis

Objective

This study was performed to introduce a new method of minimally invasive subtalar arthrodesis (MISA) and assess its clinical effects on traumatic subtalar arthritis (TSA).

Methods

Fifteen patients (8 male and 7 female; age range, 36–56 years; mean age, 48.67 years) with TSA who underwent MISA were included. All patients were treated using a series instrument. The intraoperative and postoperative indexes were recorded.

Results

Among all patients, the mean operation time was 59.67 ± 16.31 minutes and the mean intraoperative blood loss was 43.33 ± 52.87 mL. Four patients underwent iliac crest bone graft surgery, and one patient developed a complication involving fat liquefaction of the iliac crest wound. The mean bony fusion time among all patients was 3.5 months. According to the American Orthopaedic Foot and Ankle Society standard, an excellent outcome was obtained in eight patients and a good outcome was obtained in seven patients. The operation time and intraoperative blood loss were significantly different between patients who did and did not undergo iliac crest bone graft surgery.

Conclusion

MISA is a simple and effective method for the treatment of TSA.

Analysis of the stress distribution of the subtalar joint and fusion efficacy after double-screw insertion

BACKGROUND

Screw fixation is a typical technique for the isolated subtalar joint. However, no consensus has been reached on how to select the most suitable insertion position and direction. This study aims to find the ideal screw insertion and then explore its influence on the clinical efficacy of subtalar fusion by analyzing the effects of different cannulated screw insertions on the stress distribution, anti-rotary strength, and anti-inversion/eversion strength of the subtalar joint.

METHODS

In this study, we investigated three cannulated screw insertions for subtalar fusion: screw insertion with the most uniform stress distribution (group A), lateral-medial parallel screw insertion (group B), and traditional longitudinally parallel screw insertion (group C). The effects of these three insertions on the loading stress of the subtalar joint (including stress distribution, anti-inversion/eversion strength, and anti-rotary strength) were comparatively analyzed with the three-dimensional finite element method to screen the ideal screw insertion. Moreover, a prospective study was conducted to analyze the influence of the ideal screw insertion on subtalar fusion, including the fusion rate, fusion time, and clinical efficacy (VAS score, AOFAS score, and complications).

RESULTS

Group B was worse than group A with respect to the stress distribution uniformity, but slightly better than group C, and better than both groups A and C in terms of the anti-rotary strength and anti-inversion/eversion strength. The screw insertion based on the most uniform stress distribution is not feasible in surgery. Therefore, the lateral-medial antiparallel screw insertion is the ideal insertion. From January 2012 to June 2016, 48 cases were treated by subtalar fusion with the ideal screw insertion, and then followed up for 30.6 months (12-48 months). The fusion was proved in all 48 cases with a fusion rate of 100% by X-ray or CT scan. The mean time of fusion was 12.8 weeks (12-16 weeks). The VAS score decreased from 6.00 before operation to 1.03 on the last visit (P < 0.05), and the AOFAS score increased from 57.0 to 85.6 (P < 0.05), with a good and excellent rate of 95.8%.

CONCLUSIONS

The lateral-medial parallel screw insertion not only demonstrates a good stress distribution profile of the subtalar joint but also has advantages such as easy localization and operation during surgery, as well as a high fusion rate and few complications after surgery. Therefore, it is a safe, accurate, and effective fixation mode that is worthy of being popularized clinically.

The Effectiveness of Surgical Interventions in the Management of Malunited Calcaneal Fractures: A Systematic Review

Nonoperative management may result in calcaneal malunion with consequences of pain, deformity, and functional limitation. The aim of this review was to proffer an evidence-based scientific account of the effectiveness of contemporary surgical procedures in the management of malunited calcaneal fractures after initial conservative management. This systematic review included studies that evaluated the surgical procedures in the management of calcaneal malunion and systematically searched studies published between January 2005 and June 2016. The search was conducted using the following search engines: the Cochrane Library, Web of Science, PubMed/ MEDLINE, EMBASE, CINAHL, Academic Search Premier, and Open Grey. Methodologic assessment was conducted using the Cochrane Risk of Bias In nonrandomized Studies- of Interventions assessment tool version 7. Ten observational studies (212 patients) were included in this review. Five articles explored various means of achieving subtalar arthrodesis, 2 articles evaluated joint-sparing osteotomies, 1 examined corrective osteotomy for extra-articular os calcis malunion, and 2 articles explored combined procedures based on the Stephen and Sanders calcaneal malunion classification. Clinical and methodologic heterogeneity did not allow quantitative pooling of results. The overall risk of bias was considered moderate in 7 studies and 3 were considered at high risk of bias. The inability for any study to be considered at low risk of bias in this review might be mainly attributed to the lack of a valid and reliable outcome measure for the assessment of foot and ankle conditions. There is clear evidence that appropriately indicated procedures are effective in terms of pain alleviation, correction of deformity, and improved function. However, long-term outcomes may improve the acceptability to joint-preserving osteotomies, subtalar arthrodesis with the VIRA implant and subtalar distraction osteogenesis.

Open Technique for In Situ Subtalar Fusion

The subtalar joint plays an important role for the hindfoot when accommodating during gait. Joint degeneration may be caused by posttraumatic, inflammatory, and pathologic biomechanical changes. Once conservative treatment has failed, subtalar fusion should be considered. The indication for surgery is based on thorough clinical and radiographic evaluation. Several techniques for subtalar fusion are published in literature. This article aims to describe a technique for in situ arthrodesis of the subtalar joint, paying special attention to biomechanical aspects as well as preoperative clinical and radiological work-up.

Subtalar Arthroscopic Fusion

Arthroscopic subtalar fusion is an excellent approach to subtalar pathologic condition where conservative treatment has failed and a fusion has been indicated. Formal contraindications include excessive malalignment and bone loss. The posterior arthroscopic approach is analyzed in this article, including indications, surgical technique, surgical tips, and complications. Excellent results can be expected, including a shorter time to fusion, and faster rehabilitation, including activities of daily living and sports.

Arthroscopic posterior subtalar arthrodesis for salvage of posttraumatic arthritis following calcaneal fractures

BACKGROUND

Subtalar arthrodesis is a treatment option for pain due to posttraumatic arthritis following calcaneal fractures. The goal of this study is to examine the results of arthroscopic subtalar arthrodesis for posttraumatic arthritis following calcaneal fractures.

PATIENTS AND METHODS

We performed a retrospective case series reviewing 37 consecutive patients (36 male) treated for posttraumatic arthritis following calcaneal fractures by arthroscopic subtalar arthrodesis. The fractures were due to high-energy injuries in 81% of cases, and 12 fractures (32.4%) had been previously treated with internal fixation. Average follow-up was 57.5 months.

RESULTS

Average American Orthopedic Foot and Ankle Society (AOFAS) scores significantly improved from 49.0 ± 10.9 points preoperatively to 76.0 ± 8.0 points at final follow-up. Average time to union was 12.5 weeks. Six patients (16.2%) suffered complications: superficial wound infection (2.7%), symptomatic hardware that warranted removal (5.4%) and nonunion (8.1%) presented nonunion. All three cases had prior internal fixation through an extensile lateral approach, and fused after a repeat surgery.

CONCLUSION

Arthroscopic subtalar arthrodesis offers consistent improvement in cases of posttraumatic arthritis following calcaneal fractures, with a union rate similar to published series of open arthrodesis. We observed more nonunions in patients who had been treated previously with internal fixation. In spite of this, we continue to recommend arthroscopic subtalar arthrodesis, as it preserves the soft tissue envelope better than open techniques.

Anatomical Study of the Cervical and Interosseous Talocalcaneal Ligaments of the Foot with Surgical Relevance

There is conflicting evidence regarding the morphology and orientation of the cervical ligament (CL) and interosseous talocalcaneal ligament (ITCL). The morphology of the CL and its relationship to the ITCL were studied to obtain an understanding of these structures. Twenty-six feet (13 left, 13 right) were obtained from formalin-fixed cadavers (14 females, four males) with the mean standard deviation (SD) age at death 80.9 (12.9) years. All measurements were made with a digital caliper. The length and width of the foot, the width and height of the talus, were measured. The talus was cut coronally to expose the ITCL and qualitative observations were noted. The mean (SD) heights and widths of the CL at the anterior, posterior, superior, and inferior points were 8.27 (2.52), 13.95 (5.96), 9.15 (2.45), and 11.90 (4.30) mm, respectively. The mean (SD) thicknesses of the CL at the superoanterior, superoposterior, inferoanterior, inferoposterior, and central points were 0.62 (0.24), 1.05 (0.30), 0.70 (0.26), 1.20 (0.34), and 0.97 (0.31) mm, respectively. The fibers of the CL are oriented at a slight superoanterior to inferoposterior angle, whereas the fibers of the ITCL are oriented in a slight superomedial to inferolateral angle. The fibers of the CL and ITCL overlap inside the tarsal sinus with the CL positioned anteriorly, which helps to distinguish the two ligaments. In this study, we identified the morphometrics of the CL and described the CL and ITCL qualitatively. These results are relevant to introducing innovative techniques for reconstructive surgery of the subtalar ligaments in order to repair, for example, subtalar instability.

[Application and research progress of subtalar distraction bone block arthrodesis in treatment of calcaneus fracture malunion]

Objective

To review the application and research progress of subtalar distraction bone block arth-rodesis in the treatment of calcaneus fracture malunion.

Methods

The recent literature concerning the history, surgical technique, postoperative complication, indications, and curative effect of subtalar distraction arthrodesis with bone graft block interposition in the treatment of calcaneus fracture malunion was summarized and analyzed.

Results

Subtalar distraction bone block arthrodesis is one of the main ways to treat calcaneus fracture malunion, including a combined surgery with subtalar arthrodesis and realignment surgery for hindfoot deformity using bone block graft. The advantage is on the base of subtalar joint fusion, through one-time retracting subtalar joint, the posterior articular surface of subtalar joint implants bone block can partially restore calcaneal height, thus improving the function of the foot. Compared with other calcaneal malunion treatments, subtalar distraction arthrodesis is effective to correct complications caused by calcaneus fracture malunion, and it can restore the height of talus and calcaneus, correct loss of talocalcaneal angle, and ease pain.

Conclusion

Subtalar distraction bone block arthrodesis has made remarkable progress in the treatment of calcaneus fracture malunion, but it has the disadvantages of postoperative nonunion and absorption of bone block, so further study is needed.

Posterior Arthroscopic Subtalar Arthrodesis: Clinical and Radiologic Review of 19 Cases

Arthroscopic subtalar arthrodesis has recently gained popularity in the treatment of primary subtalar or post-traumatic arthritis, coalition, or inflammatory diseases with subtalar arthritis. The present study reports the clinical and radiologic results of 19 patients (19 feet) who underwent posterior arthroscopic subtalar arthrodesis using 2 posterior portals. A total of 19 posterior arthroscopic subtalar arthrodeses (minimum follow-up of 24 months) performed without a bone graft and with 2 parallel screws were prospectively evaluated. The fusion rate was 94% (mean time to fusion 9.8 weeks). Modified American Orthopaedic Foot and Ankle Society ankle-hindfoot scale score (maximum 94 points) improved significantly from 43 to 80 points and the visual analog scale for pain score improved from 7.6 to 1.2. The 12-item short-form physical and mental scores at the last follow-up point were 52.5 and 56.4, respectively. One (5.3%) patient underwent open repeat fusion for nonunion, 2 (10.5%) patients required a second procedure for implant removal, and 1 (5.3%) experienced reversible neuropraxia. In conclusion, posterior arthroscopic subtalar arthrodesis is a safe technique with a good union rate and a small number of complications in patients with no or very little hindfoot deformity.

Subtalar arthroscopic arthrodesis: Technique and outcomes

PURPOSE

The goal of this study was to describe the surgical technique and our results with arthroscopic posterior subtalar arthrodesis.

MATERIAL AND METHODS

Retrospective case series of 65 patients (38 men and 27 women) averaging 50 years of age (range 21-72 years) undergoing posterior arthroscopic subtalar arthrodesis using one or two percutaneous 6.5-7.3mm screws between May 2004 and February 2011, with a mean follow-up of 57.5 months (range 24-105 months).

RESULTS

We achieved a 95.4% union rate after an average of 12.1 weeks (range 9 to 16 weeks). 12.3% of patients suffered complications, including superficial infection, nonunion and need for hardware removal. The AOFAS score improved from 51.5 points (19-61 points) preoperatively to 81.9 points (60-94 points) in the postoperative period.

CONCLUSIONS

We describe the surgical technique for arthroscopic subtalar arthrodesis, which as proven to be a safe and reliable technique in our experience, with consistent improvements in AOFAS scores.

Compressive Force With 2-Screw and 3-Screw Subtalar Joint Arthrodesis With Headless Compression Screws

BACKGROUND

Joint compression is an essential element of successful arthrodesis. Although subtalar joint compression generated by conventional screws has been quantified in the laboratory, compression obtainable with headless screws that rely on variable thread pitch to achieve bony contact has not been assessed. This study measured subtalar joint compression achieved by 2 posteriorly placed contemporary headless, variable-pitch screws, and quantified additional compression gained by placing a third screw anteriorly.

METHODS

Ten, unpaired fresh-frozen cadaveric subtalar joints were fixed sequentially using 2 diverging posterior screws (one directed into the talar dome, the other into the talar neck), 2 parallel posterior screws (both ending in the talar dome), and 2 parallel screws with an additional anterior screw inserted from the plantar calcaneus into the talar neck. Joint compression was quantified directly during screw insertion using a novel custom-built measuring device.

RESULTS

The mean compression generated by 2 diverging posterior screws was 246 N. Two parallel posterior screws produced 294 N of compression, and augmentation of that construct with a third, anterior screw increased compression to 345 N (P < .05). Compression subsequent to 2-screw fixation was slightly less than that reported previously for subtalar joint fixation with 2 conventional lag screws, but was comparable when a third screw was added.

CONCLUSIONS

Under controlled testing conditions, 2 tapered, variable-pitch screws generated somewhat less compression than previously reported for 2-screw fixation with conventional headed screws. A third screw placed anteriorly increased compression significantly.

CLINICAL RELEVANCE

Because headless screws are advantageous where prominent screw heads are problematic, such as the load-bearing surface of the foot, their effectiveness compared to other screws should be established to provide an objective basis for screw selection. Augmenting fixation with an anterior screw may be desirable when conditions for fusion are suboptimal.

Arthroscopic subtalar arthrodesis

Arthroscopic subtalar arthrodesis is gaining in popularity based on evidence of bone fusion in over 90% of cases, with a shorter time to healing, a simpler postoperative course, and fewer complication compared to open surgery. Two arthroscopic techniques have been reported: one with the patient in lateral decubitus and lateral portals and the other with the patient prone and posterior portals. The objective of this technical note is to describe these two techniques, with emphasis on the specific characteristics of each.

Predictors of Nonunion and Infectious Complications in Patients With Posttraumatic Subtalar Arthrodesis

OBJECTIVE

The objective of the present study was (1) to identify predictors of both nonunion and postoperative wound infections (POWI) and (2) to assess the union and complication rate following posttraumatic subtalar arthrodesis (STA).

DESIGN

Retrospective comparative cohort study.

SETTING

Level 1 trauma center.

PATIENTS

All consecutive adult patients with STA following traumatic injuries between 2000 and May 2015.

INTERVENTION

STA for posttraumatic deformities.

MAIN OUTCOME MEASUREMENTS

Union (described as a combination of radiographic signs of osseous bridging and a clinically fused joint) and POWI as classified by the Centers for Disease and Control.

RESULTS

A total number of 93 (96 feet) patients met the inclusion criteria. Union was achieved in 89% of patients. For primary, secondary in situ, and secondary correction arthrodesis, these percentages were 94%, 84,% and 90%, respectively (NS). The union rate significantly increased over time (P = 0.02). In 17 patients (18%), a POWI occurred, of which 2 were classified as superficial and 15 as deep POWIs. The POWI rate did not differ between the groups. Alcohol, nicotine, and drug abuse were not significantly associated with the occurrence of POWIs. Patients with an open fracture or an infection following open reduction internal fixation had a greater risk of a POWI following STA (P = 0.03 and P = 0.04, respectively).

CONCLUSIONS

We could not identify predictors for nonunion. In 18% of the patients, an infectious complication following surgery occurred. Patients with an open fracture or an infection after primary surgical treatment (ie, open reduction internal fixation) have a higher chance of POWIs following STA. The union rate following posttraumatic STA is 89%.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Minimally Invasive Surgery for Tibiotalocalcaneal Arthrodesis Using a Retrograde Intramedullary Nail: Preliminary Results of an Innovative Modified Technique

The aim of the present longitudinal prospective study was to evaluate the clinical, functional, and radiologic outcomes and patient satisfaction of those who had undergone minimally invasive surgery (MIS) for tibiotalocalcaneal arthrodesis with an intramedullary nail. The 28 patients, who had consecutively undergone surgery with the MIS technique, were evaluated clinically and radiographically at 1, 2, 3, and 6 months after surgery and at last follow-up examination. For the clinical evaluation, the American Orthopaedic Foot and Ankle Society scale and visual analog scale for the foot and ankle were used in the preoperative and final follow-up examinations. The patients rated their satisfaction on a scale from 0 to 10. The mean score obtained with the American Orthopaedic Foot and Ankle Society scale was 68.28 ± 5.02 (range 58 to 74) points and with the visual analog scale for the foot and ankle was 70.76 ± 7.72 (range 58 to 82) points, with a mean follow-up of 25.07 ± 6.32 (range 6 to 40) months. The clinical improvement was statistically significant with both types of evaluation (p ≤ .05), comparing the preoperative and follow-up periods. Fusion was achieved in all patients, with a mean fusion time of 14.85 ± 4.12 (range 8 to 56) weeks. The alignment of the ankle and foot was optimal in 27 of 28 patients (96.42%), and patient satisfaction was rated as 6.71 ± 1.37 (range 5 to 10) points. Finally, the use of MIS for tibiotalocalcaneal arthrodesis with intramedullary nail results in fusion of the articulation with a low complication rate.

Arthroscopic Medial Approach for Modified Double Arthrodesis of the Foot

The single medial incision subtalar joint and talonavicular joint arthrodesis has been shown to be a useful alternative for the correction of hindfoot valgus deformity. We describe an arthroscopic method of joint preparation using this approach. The present case report included 6 consecutive patients aged 35 to 72 (mean ± standard deviation 55.8 ± 15.54) years (4 males [66.7%] and 2 females [33.3%]), who had undergone the medial approach for modified double arthrodesis of the foot. Of the 6 patients, 3 (50.0%) had undergone arthroscopic joint preparation and 3 (50.0%) traditional (manual) joint preparation. Osteobiologic agents were used in all patients. We found a shorter tourniquet time for the patients who had undergone an arthroscopic approach, with a mean of 110 ± 7.21 minutes, compared with a traditional joint preparation, with a mean of 121.3 ± 8.08 minutes. We also found a shorter time to radiographic union in the patients who had undergone an arthroscopic approach, all of whom showed signs of union at 6 weeks. Only 2 of the 3 patients in the traditional joint preparation group had achieved union at a mean of 10 ± 2.83 weeks, with 1 case resulting in nonunion. This technique could be a viable alternative to traditional methods of joint preparation by decreasing the operative time and improving the union rates.

Results of Arthroscopic Subtalar Arthrodesis for Adult-Acquired Flatfoot Deformity vs Posttraumatic Arthritis

BACKGROUND

The goal of this study was to compare results with arthroscopic posterior subtalar arthrodesis between patients treated for adult-acquired flatfoot deformity (AAFD) due to posterior tibial tendon dysfunction and patients with posttraumatic subtalar arthritis.

METHODS

Retrospective case series of 61 consecutive patients (group 1: posttraumatic arthritis, n = 37; group 2: AAFD, n = 24) averaging 49 years of age (range, 21-72 years) undergoing posterior arthroscopic subtalar arthrodesis via 1 or 2 percutaneous 6.5- to 7.3-mm screws, with a mean follow-up of 57.5 months (range, 24-105 months). Fusion was defined as the appearance of bony trabeculae across the subtalar joint on standard x-rays, along with clinical signs of union.

RESULTS

Patients with posttraumatic arthritis (group 1) were more predominantly male and younger than patients treated for AAFD (group 2). Overall, we achieved a 95.1% radiologic union rate after an average of 11.7 weeks. Complications appeared in 14.8% of patients. Union rate and complications did not differ significantly between groups. American Orthopaedic Foot & Ankle Society (AOFAS) scores improved significantly for both patient groups, although patients with AAFD showed significantly larger improvement and higher postoperative AOFAS scores, even after adjusting for age and sex (mean improvement in AOFAS scores: 27.0 ± 9.1 points for the posttraumatic arthritis group vs 34.9 ± 7.4 points for the AAFD group; P < .001).

CONCLUSIONS

Arthroscopic subtalar arthrodesis was a safe and reliable technique, with consistent improvement in AOFAS scores throughout different patient subgroups, as well as comparable time to union and complication rates. Improvements were larger for patients treated for AAFD, even after adjusting for age and sex.

LEVEL OF EVIDENCE

Level III, retrospective case series.

Arthroscopic Posterior Subtalar Arthrodesis: Surgical Technique

Surgical fusion of the subtalar joint is a procedure indicated to alleviate pain of subtalar origin, such as in post-traumatic osteoarthritis, adult-acquired flatfoot deformity, and other disorders. Open subtalar arthrodesis has been performed with predictable results, but concerns exist regarding injury to proprioception and local vascularity due to wide surgical dissection. Minimally invasive techniques try to improve results by avoiding these issues but have a reputation for being technically demanding. We describe the surgical technique for arthroscopic subtalar arthrodesis, which has proved to be a safe and reliable technique in our experience, with consistent improvements in American Orthopaedic Foot & Ankle Society scores.

Safety and efficiency of posterior arthroscopic ankle arthrodesis

PURPOSE

To study the safety and efficiency of posterior arthroscopic ankle arthrodesis.

METHODS

Ten fresh-frozen human lower leg specimens without evidence of previous surgery to the foot and ankle were selected. Arthroscopic debridement of the tibiotalar joint was performed in all specimens using a standardized protocol. Anatomical dissections were regarded the gold standard for safety analysis. To evaluate the efficacy of the posterior ankle arthroscopic arthrodesis, the debrided articular tibiotalar parts were resected and subsequently analysed using Image-analysis software, Image J (Wayne Rasband, National Institutes of Health, Bethesda, MD).

RESULTS

In none of the specimens, iatrogenic damage was detected during the anatomical dissection following the posterior ankle arthroscopic procedure. A total talar joint surface area of 95 % and total tibial joint surface area of 96 % was addressed during the arthroscopic debridement.

CONCLUSIONS

The posterior ankle arthroscopic arthrodesis can be regarded safe and is also highly effective in the debridement of cartilage, resulting in optimal biology for fusion to occur. Therefore, this new arthroscopic technique potentially will diminish existing non-union rates for the fusion of the ankle joint.

Arthroscopic triple and modified double hindfoot arthrodesis

BACKGROUND

Arthroscopic arthrodesis is an accepted technique for the ankle but less commonly reported for multiple hindfoot joints. We present a case series review to establish the feasibility of this surgery.

METHODS

In a consecutive series of 112 arthroscopic hindfoot arthrodeses, 18 involved decortication and fusion of 2 or 3 hindfoot joints. These were reviewed to identify complications, union rates and improvement over preoperative state.

RESULTS

Mean age was 62 (45-78). Mean follow-up was 4.4 (1.75-7.5) years. There were no perioperative complications. The four patients with triple fusions united with good or excellent outcomes. Of 14 patients with subtalar and talonavicular arthrodeses there were three talonavicular non-unions.

CONCLUSIONS

Arthroscopic double and triple arthrodeses appear feasible salvage options for pain and deformity. Decortication of all three joints and rotatory correction of deformity is possible whilst preserving the soft tissue envelope. Late adjacent joint pain and arthrosis can occur.

Subtalar joint arthrodesis: open and arthroscopic indications and surgical techniques

Arthrodesis of the subtalar joint can be performed via both open and arthroscopic techniques. Both groups of procedures have their own relative indications and contraindications, as well as complications. Good results have been reported for both general procedures, although some studies suggest superiority with arthroscopic subtalar arthrodesis.

Effects on Subtalar Joint Stress Distribution After Cannulated Screw Insertion at Different Positions and Directions

We investigated the effects on subtalar joint stress distribution after cannulated screw insertion at different positions and directions. After establishing a 3-dimensional geometric model of a normal subtalar joint, we analyzed the most ideal cannulated screw insertion position and approach for subtalar joint stress distribution and compared the differences in loading stress, antirotary strength, and anti-inversion/eversion strength among lateral-medial antiparallel screw insertion, traditional screw insertion, and ideal cannulated screw insertion. The screw insertion approach allowing the most uniform subtalar joint loading stress distribution was lateral screw insertion near the border of the talar neck plus medial screw insertion close to the ankle joint. For stress distribution uniformity, antirotary strength, and anti-inversion/eversion strength, lateral-medial antiparallel screw insertion was superior to traditional double-screw insertion. Compared with ideal cannulated screw insertion, slightly poorer stress distribution uniformity and better antirotary strength and anti-inversion/eversion strength were observed for lateral-medial antiparallel screw insertion. Traditional single-screw insertion was better than double-screw insertion for stress distribution uniformity but worse for anti-rotary strength and anti-inversion/eversion strength. Lateral-medial antiparallel screw insertion was slightly worse for stress distribution uniformity than was ideal cannulated screw insertion but superior to traditional screw insertion. It was better than both ideal cannulated screw insertion and traditional screw insertion for anti-rotary strength and anti-inversion/eversion strength. Lateral-medial antiparallel screw insertion is an approach with simple localization, convenient operation, and good safety.

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.

Differential efficacy of subtalar fusion with three operative approaches

Background

There are many existing operative approaches for subtalar fusion; however, no optional strategy of operative approach has been developed yet. This study aimed to analyze the differential clinical efficacy of subtalar fusion with three operative approaches.

Methods

The clinical data of 102 patients from April 2008 to April 2012 were analyzed prospectively. These patients were divided into three groups with the random number table: group A, group B, and group C. The following parameters were compared among three groups: effective exposure area and exposure time of subtalar joint, intraoperative bleeding volume, postoperative complications, fusion time, fusion rate, AOFAS score and VAS score before and after operation.

Results

In the exposure area score, there was no statistically significant difference between group A and group C (P >0.05) ,but with a statistically significant difference between group A/C and group B (P <0.05). In exposure time and intraoperative bleeding volume, there was no statistically significant difference between group A and group B (P >0.05) but with a statistically significant difference between group A/B and group C (P <0.05). In three groups, there was a statistically significant difference in both AOFAS score and VAS score before operation and at 6 months/12 months/last visit after operation (P <0.05). The incidence of complications in the three groups was 8.8%, 12.5% and 19.4%. No statistically significant differences in fusion rate and fusion time were observed among the three groups (P >0.05).

Conclusion

Three operative approaches have different indications, All the three operative approaches do not influence the fusion rate and fusion time of subtalar joint. The lateral tarsal sinus approach is inferior to the posterior-lateral L approach and the approach from the inferior tip of fibula to the basilar part of the fourth metatarsal bone in the exposure area, while the lateral tarsal sinus approach and the approach from the inferior tip of fibula to the basilar part of the fourth metatarsal bone are superior to the posterior-lateral L approach in the exposure time, intraoperative bleeding volume, and incidence of complications.

Level of evidence

Therapeutic, level III.

Arthroscopic triple fusion joint preparation using two lateral portals: a cadaveric study to evaluate efficacy and safety

BACKGROUND

Arthroscopic triple fusion has several advantages over open techniques, but its use has yet to become widespread. Preliminary published techniques use five portals with neurovascular risk. Our aim was to assess the safety and efficacy of an alternative lateral two portal technique.

METHODS

Four cadaveric hindfeet were arthroscopically prepared for a triple fusion using two lateral portals. The distance to relevant subcutaneous nerves was measured as well as the prepared joint surface percentage.

RESULTS

Mean distance from mid-lateral portal to the nearest sural nerve branch was 22.3mm (range 20-24mm) and from the dorsolateral portal to the intermediate branch of the superficial peroneal nerve was 7.8mm (range 4-11mm). Mean percentages of joint preparation were 63% (talar head), 62% (navicular), 75% (calcaneum) and 74% (cuboid).

CONCLUSIONS

Two lateral arthroscopic portals allow adequate joint preparation for triple fusion procedures. The proximity of subcutaneous nerves is important to appreciate when using these portals.

Safety and efficiency of a 2-portal lateral approach to arthroscopic subtalar arthrodesis: a cadaveric study

PURPOSE

To investigate the safety and efficiency of a 2-portal lateral (anterior and middle) approach to arthroscopic subtalar arthrodesis.

METHODS

A cadaveric study was performed on 30 feet of 15 fresh cadaveric bodies (15 right and 15 left; 21 female specimens and 9 male specimens). The mean age at death was 78 ± 6.7 years. The procedure was performed with the specimen in the supine position through 2 lateral (anterior and middle) sinus tarsi portals by use of a 4.0-mm arthroscope. A 3.5-mm synovial shaver was used for debridement, and a 4.5-mm shielded bur was used to resect posterior subtalar facets. The feet were then dissected. The primary outcomes were the percentage of resected joint surface and the distances between portals and both sural and superficial peroneal nerves. The secondary outcomes were injury of sinus tarsi ligaments and lateral arterial network, calcaneofibular ligament, peroneal tendons, flexor hallucis longus tendon, and posterior tibial neurovascular bundle.

RESULTS

The mean percentages of resected talar and calcaneal posterior subtalar facets were 94% ± 7.2% and 91% ± 6.8%, respectively. The minimum distance of either subtalar portal to the nerves was 4 mm. No nerve injury was observed. In 28 of 30 cases, the lateral sinus tarsi arterial network was found intact. In all cases the inferior retinaculum extensor was transfixed by the portals. In all cases both cervical and interosseous talocalcaneal ligaments were found intact. In 3 cases a shaving lesion was observed on the peroneus brevis tendon.

CONCLUSIONS

According to this cadaveric study, more than 90% freshening of the posterior subtalar articular facets can be achieved through a 2-portal lateral (anterior and middle) approach. This technique is reproducible and safe with regard to the surrounding nerves.

CLINICAL RELEVANCE

The 2 lateral portals may offer a safe and effective alternative approach for arthroscopic arthrodesis of the posterior subtalar joint.

Surgical Management of Calcaneal Malunion

Calcaneal malunion is a common complication after conservative treatment or incorrect surgical treatment of calcaneal fracture. The typical pathoanatomies of calcaneal malunion are subtalar joint incongruity, loss of calcaneal height, arch collapse, varus or valgus deformity of the calcaneus, heel widening and so on. Calcaneal malunion often needs to be treated surgically. The classification of calcaneal malunion and the detailed clinical and radiographical assessment play important roles for surgical option. The main surgical methods include in situ subtalar arthrodesis, reconstruction of calcaneal thalamus and subtalar arthrodesis, calcaneal osteotomy with subtalar arthrodesis, corrective calcaneal osteotomy without subtalar arthrodesis. Each option has its different indications, advantages and disadvantages. Thus, the surgical treatment should be individualised.

Posterior approach for subtalar joint distraction arthrodesis by compact external fixation: a technique guide

Subtalar joint arthrodesis is a commonly used surgical procedure for the management of rearfoot pathologic features. We present a technique guide for a posterior incisional approach to subtalar joint arthrodesis for correction of a calcaneal deformity secondary to calcaneal fracture malunion. This technique uses a monolateral external fixation device for controlled distraction and intercallary allograft placement. In contrast to a standard lateral approach, this incision provides better visualization of the joint space, and the use of a distractor enhances access to the joint surfaces for fusion preparation and maintains alignment while internal fixation is applied. A 44-year-old male underwent isolated subtalar joint arthrodesis to repair a malunion of a nonsurgically managed calcaneal fracture sustained 1 year before the surgical intervention. Controlled distraction was applied using a Hoffmann(®) Compact™ MRI external fixation device. This device maintained distraction and tibial-calcaneal alignment until placement of the allograft-bone marrow aspirate. The use of external fixation is a viable option for distraction arthrodesis in subtalar joint fusions. It facilitates frontal plane deformity correction. We have described the surgical technique and presented a case in which the posterior approach with distraction was successfully used in subtalar joint arthrodesis. At 12 weeks postoperatively, serial radiographs displayed incorporation of the graft, with distraction maintained at the subtalar joint arthrodesis site. At the 3-month follow-up visit, the patient had successfully transitioned to weightbearing in a CAM walker without any complications.

A technique of lateral process blockade for subtalar joint fusion: an easy, economical, and effective method to prevent rotation

One of the most common debates in discussing the technique of isolated subtalar joint arthrodesis is whether a single point of fixation is adequate to achieve joint fusion. The single screw technique places a fixation device in line with the subtalar joint axis of motion. Regardless of whether the screw is run up from the plantar calcaneus or down from the talar neck, rotational movement can occur about this axis. This motion increases the risk of delayed union, misalignment, and nonunion of bone. Therefore, the use of a second point of fixation has been considered by many surgeons to be prudent, as a method to further stabilize the site of fusion by preventing rotary motion about the interfragmental compression screw. The following is a description of a lateral talar process blockade using a cut and bent Rush rod. This method is an easy, economical, and effective method of preventing rotary motion at the talocalcaneal interface when performing subtalar joint fusion.

Total ankle replacement using HINTEGRA, an unconstrained, three-component system: surgical technique and pitfalls

Total ankle replacement (TAR) has become a valuable treatment option in patients with end-stage ankle osteoarthritis. One popular 3-component system, the HINTEGRA TAR, is an unconstrained system that provides inversion-eversion stability. More natural biomechanics of the replaced ankle may be expected when anatomic considerations drive prosthesis design. The HINTEGRA prosthesis includes 2 anatomically contoured metal components and a polyethylene insert, providing axial rotation and physiologic flexion-extension mobility. This article describes the HINTEGRA TAR design and surgical technique. Use of the prosthesis for complex hindfoot reconstruction in patients with an osteoarthritic, varus, or valgus ankle deformity is described.