Ankle arthrodesis: A long term review of the literature

A biomechanical study comparing the compression force and osseous area of contact of two screws fixation techniques used in ankle joint arthrodesis model

INTRODUCTION

Arthrodesis of a (diseased) ankle joint is usually performed to achieve pain relief and stability. One basic principle of arthrodesis techniques includes rigid fixation of the surfaces until union. It seems plausible that stable anchoring and homogeneous pressure distribution should be advantageous, however, it has not been investigated yet. The aim is to achieve uniform compression, as this is expected to produce favorable results for the bony fusion of the intended arthrodesis. Numerous implants with different biomechanical concepts can be used for ankle fusion. In this study, headless compression screws (HCS, DePuy Synthes, Zuchwil, Switzerland) were compared biomechanically to an alternative fixation System, the IOFix device (Extremity Medical, Parsippany, NJ, USA) in regard to the distribution of the compression force (area of contact) and peak compression in a sawbone arthrodesis-model (Sawbones® Pacific Research Laboratories, Vashon, WA, USA). This study aims to quantify the area of contact between the bone interface that can be obtained using headless compression screws compared to the IOFix. In current literature, it is assumed, that a large contact surface with sufficient pressure between the bones brings good clinical results. However, there are no clinical or biomechanical studies, that describe the optimal compression pressure for an arthrodesis.

MATERIAL AND METHODS

Two standardized sawbone blocks were placed above each other in a custom-made jig. IOFix and headless compression screws were inserted pairwise parallel to each other using a template for a uniform drilling pattern. All screws were inserted with a predefined torque of 0.5 Nm. Pressure transducers positioned between the two sawbone blocks were compressed for the measurement of peak compression force, compression distribution, and area of contact.

RESULTS

With the IOFix, the compression force was distributed over significantly larger areas compared to the contact area of the HCS screws, resulting in a more homogenous contact area over the entire arthrodesis surface. Maximum compression force showed no significant difference.

CONCLUSION

The IOFix system distributes the compression pressure over a much larger area, resulting in more evenly spread compression at the surface. Clinical studies must show whether this leads to a lower pseudarthrosis rate.

Tibiotalocalcaneal ankle arthrodesis with posterior approach arthroscopic-assisted hindfoot nailing

PURPOSE

End-stage ankle arthrosis causes severe pain and limited movement. Tibiotalocalcaneal arthrodesis with arthroscopy-assisted hindfoot nailing can be used to achieve a high union rate and low complication rate. We aimed to examine the early- and mid-term results of patients treated with this technique from various perspectives and to evaluate them by comparing them with the current literature.

METHODS

Data were collected from 25 patients who met the established criteria and underwent TTCA with arthroscopic-assisted hindfoot nailing. In addition to the demographic data of the patients, their clinical and pain scores were evaluated using the American Orthopedic Foot and Ankle Society (AOFAS) and visual analogue scale (VAS). Additionally, the union time and complication data during the follow-up period were examined.

RESULTS

When the AOFAS and VAS scores of the 25 patients were examined, a significant improvement was observed in the preoperative period and early postoperative period comparisons (p < .001). No significant change was observed between the comparison of the postoperative 12th month and last postoperative control clinical scores. While the union rate of the patients was observed to be 92%, the average union time was 13.1 ± 3.5 weeks. During follow-up, peri-implant fracture, deep infection, and non-union were observed in one patient each (12%).

CONCLUSION

The early- and mid-term postoperative results of patients treated with TTCA surgery with posterior approach arthroscopic-assisted hindfoot nailing show that this technique may be an option with low complication and high union rates for the appropriate group of patients planned for ankle arthrodesis.

Comparison of different internal fixation models in ankle arthrodesis using 3D finite-element analysis

BACKGROUND

The purpose of this study is to use three-dimensional finite-element analysis to better understand the biomechanical features of various internal fixators for ankle arthrodesis.

METHODS

We used finite-element analysis to compare four different types of internal fixations in ankle arthrodesis: Group A had three crossed screws (Ø6.5 mm); Group B had two crossed screws (Ø6.5 mm) and an anterior plate (Ø2.7 mm); Group C only had an anterior anatomical plate (Ø3.5 mm); Group D had one anterior anatomical plate (Ø3.5 mm) and one posterior-lateral screw (Ø6.5 mm). We adopted Ansys 21.0 software to analyze and compare the four types in terms of the displacement of the arthrodesis surface and the stress peak and stress distribution of these models under intorsion, extorsion, dorsiflexion torque, and neutral vertical load.

RESULTS

① Displacement of the arthrodesis surface: In Group A, the maximum displacement was larger than Group D under neutral vertical load and dorsiflexion torque but less than it under intorsion and extorsion torque. In Group B, the maximum displacement against dorsiflexion, neutral vertical load, intorsion, and extorsion was less than that in the other three fixation models. In Group C, the maximum displacement against the above four loading patterns were significantly higher than that in another three fixation models. ② Stress peak and stress distribution: based on the stress distribution of the four models, the peak von Mises stress was concentrated in the central sections of the compression screws, plate joints, and bending parts of the plates.

CONCLUSIONS

The fixation model consisting of two crossed screws and an anterior outperformed the other three fixation models in terms of biomedical advantages; thus, this model can be deemed a safe and reliable internal fixation approach for ankle arthrodesis.

The value of bone SPECT/CT in evaluation of foot and ankle arthrodesis and adjacent joint secondary osteoarthritis

OBJECTIVE

To evaluate the value of SPECT/CT (single photon emission computed tomography/computed tomography) in foot and ankle arthrodesis and development of secondary osteoarthritis in the adjacent joints.

MATERIALS AND METHODS

SPECT/CT of 140 joints in the foot and ankle (34 upper ankle (UA), 28 lower ankle (LA), 27 talonavicular (TN), 12 calcaneo-cuboidal (CC), and 39 other smaller joints after arthrodesis in 72 patients were evaluated retrospectively regarding fusion grade in CT (0 = no fusion, 1 =  < 50% fusion, 2 =  > 50% fusion, 3 = complete fusion) and radiotracer uptake (0 = no uptake, 1 = mild uptake, 2 = moderate uptake, 3 = high uptake) on SPECT/CT. Severity of osteoarthritis (1 = mild, 2 = moderate, 3 = severe) and radiotracer uptake grade in adjacent joints was also assessed. In 54 patients, clinical information about interventions in the follow-up was available.

RESULTS

According to the SPECT/CT, arthrodesis was successful (grade 2 or 3 CT fusion and grade 0 or 1 uptake) in 73% (25/34) of UA joints, 71% (20/28) of LA joints, 67% (18/27) TN, 100% (12/12) CC joints, and 62% (24/39) of other smaller joints. In 12 joints, there were discrepant findings in SPECT/CT (fusion grade 2 and uptake grade 2 or 3 (n = 9); or, fusion grade 0 or 1 and uptake grade 1 (n = 3)). The fusion rate 6-12 months after arthrodesis was 42% (14/33), 59% (20/34) after 13-24 months, and 89% (65/73) after more than 24 months, respectively. Average radiotracer uptake in arthrodesis decreased with age: 6-12 months: 1.60, 12-24 months: 1.32,  > 24 months: 0.38. There was a significant negative correlation between radiotracer uptake grade and CT fusion grade. Osteoarthritis was observed in 131 adjacent joints. During the post scan follow-up, additional arthrodeses were performed in 33 joints, of which 11 joints were re-arthrodesis and 22 were new arthrodeses in osteoarthritic adjacent joints. All these 11 joints with failed arthrodesis had grade 0 of CT fusion and grade 2 or 3 of radiotracer uptake. All 22 adjacent joints with osteoarthritis, which subsequently underwent arthrodesis, had grade 2 or 3 radiotracer uptake, and the primary arthrodesis joints were healed and fused in all these cases.

CONCLUSION

Bone SPECT/CT is a valuable hybrid imaging tool in the evaluation of foot and ankle arthrodesis and gives additional useful information about the development of secondary osteoarthritis in the adjacent joints with higher value for the assessment of secondary osteoarthritis. A practical four-type classification ('Lucerne Criteria') combining metabolic and morphologic SPECT/CT information for evaluation of arthrodesis joints has been proposed.

The Fate of Delayed Unions After Isolated Ankle Fusion

BACKGROUND

Nonunion remains the most common major complication of ankle arthrodesis. Although previous studies have reported delayed union or nonunion rates, few have elaborated on the clinical course of patients experiencing delayed union. In this retrospective cohort study, we sought to understand the trajectory of patients with delayed union by determining the rate of clinical success and failure and whether the extent of fusion on computed tomography scan (CT) was associated with outcomes.

METHODS

Delayed union was defined as incomplete (<75%) fusion on CT between 2 and 6 months postoperatively. Thirty-six patients met the inclusion criterion: isolated tibiotalar arthrodesis with delayed union. Patient-reported outcomes were obtained including patient satisfaction with their fusion. Success was defined as patients who were not revised and reported satisfaction. Failure was defined as patients who required revision or reported being not satisfied. Fusion was assessed by measuring the percentage of osseous bridging across the joint on CT. The extent of fusion was categorized as absent (0%-24%), minimal (25%-49%), or moderate (50%-74%).

RESULTS

We determined the clinical outcome of 28 (78%) patients with mean follow-up of 5.6 years (range, 1.3-10.2). The majority (71%) of patients failed. On average, CT scans were obtained 4 months after attempted ankle fusion. Patients with minimal or moderate fusion were more likely to succeed clinically than those with "absent" fusion (P = .040). Of those with absent fusion, 11 of 12 (92%) failed. In patients with minimal or moderate fusion, 9 of 16 (56%) failed.

CONCLUSION

We found that 71% of patients with a delayed union at roughly 4 months after ankle fusion required revision or were not satisfied. Patients with less than 25% fusion on CT had an even lower rate of clinical success. These findings may help surgeons in counseling and managing patients experiencing a delayed union after ankle fusion.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

Tibiotarsal Arthrodesis with Retrograde Intramedullary Nail and RIA Graft: A Salvage Technique

Ankle arthrodesis is a commonly used salvage procedure in the management of post-traumatic ankle fractures, which often result in severe disability and may require the amputation of the distal third of the leg. Successful ankle arthrodesis relies on a thorough assessment of local and systemic risk factors to ensure optimal results. Failure to accurately assess these factors may lead to unsatisfactory results. High-energy trauma causing bone defects and soft tissue necrosis often results in osteomyelitis, a condition that poses a significant threat to the success of the arthrodesis procedure. It is important to apply a standardised surgical protocol to minimise the possibility of superficial and deep infection and limit damage to the neighbouring soft tissues. Therefore, it is critical to undertake surgical lavage and debridement and administer systemic and local antibiotic therapy, along with the use of a spacer, to eradicate infection prior to performing arthrodesis. In this study, we present our experience in the recovery of limbs with post-traumatic complications via tibio-astragalic or tibio-calcaneal arthrodesis using a retrograde intramedullary nail technique. The approach involves a multi-step procedure using a previous antibiotic spacer implant and an autologous bone graft (RIA). This study spanned a period from January 2014 to December 2021 and included 35 patients (12 women and 23 men) with a mean age of 47.8 ± 20.08 years (range: 22-85 years). Among the patients, 18 had osteomyelitis following AO 43 C3 fractures, and 9 of them had previous exposure and bone loss at the time of injury. The remaining cases included 10 patients with AO 44 C fracture outcomes and 7 patients with AO 44 B fracture outcomes. Our results emphasise the importance of the meticulous management of local and systemic risk factors in ankle arthrodesis procedures. The successful eradication of infection and subsequent arthrodesis can be achieved via the implementation of surgical lavage, debridement, and systemic and local antibiotic therapy using spacers. This surgical protocol implemented by us has yielded excellent results, saving affected limbs from post-traumatic complications and avoiding the need for amputation. Our study contributes to the existing knowledge supporting the use of retrograde arthrodesis with intramedullary nails in severe cases where limb salvage is the primary goal. However, further research and long-term follow-up studies are needed to validate these results and evaluate the effectiveness of this technique in a larger patient population.

Emerging role of bone scintigraphy single-photon emission computed tomography/computed tomography in foot pain management

Foot and ankle joints being weight-bearing joints are commonly subjected to wear and tear and are prone to traumatic and other pathologies. Most of these foot and ankle pathologies present with pain. The diagnosis of pathology and localization of pain generators is difficult owing to the complex anatomy of the foot and similar clinical presentation. This makes the management of foot pain clinically challenging. Conventional anatomical imaging modalities are commonly employed for evaluation of any anatomical defect; however, these modalities often fail to describe the functional significance of the anatomical lesions, especially in presence of multiple lesions which is common in ankle and foot; however, hybrid single-photon emission computed tomography/computed tomography (SPECT/CT) by virtue of its dual modalities, that is, highly sensitive functional imaging and highly specific anatomical imaging can serve as a problem-solving tool in patient management. This review attempts to describe the role of hybrid SPECT/CT in overcoming the limitation of conventional imaging and describes its potential application in the management of foot and ankle pain.

Effectiveness of Arthroscopically Assisted Surgery for Ankle Arthrodesis

Regarding the treatment of ankle arthritis, the choice of arthroscopic ankle arthrodesis (AAA) or open ankle arthrodesis (OAA) remains controversial. To guide clinical decision-making, we conducted a meta-analysis on the optimal treatment of ankle arthrodesis. We identified eligible studies published from June 1, 1969 to June 1, 2020 using the Cochrane Library, PubMed, OVID, Embase, and Medline searched the references of relevant studies. Randomized and non-randomized studies that compared outcomes of AAA and OAA were included. After the methodologic assessment, available data were extracted and statistically reviewed. The primary outcomes were overall complications rate, tourniquet time, length of the hospital stay, non-union rate, and rate to fusion. The secondary outcomes were delayed union and postoperative infection rate. We included 9 studies comparing arthroscopic and open in patients with ankle arthrodesis, comprising 467 participants. AAA had the advantage of demonstrating a lower overall complication rate (odds ratio [OR], 0.44 [95% confidence interval [CI], 0.26-0.73]; p = .002), shorter intraoperative tourniquet time (mean difference [MD], -16.49 [95% CI, -23.51 to -9.46]; p < .001), shorter length of the hospital stay (MD -1.75, 95% CI -1.94 to -1.2, p < .001),lower non-union rate (OR, -0.07 [95% CI, -0.13 to -0.02]; p <.01) and higher rate to fusion (OR, 4.2 [95% CI, 1.96-8.99]; p < .001) in comparison with OAA. Yet, no significant differences were found in delayed union (OR, 0.46 [95% CI, 0.10-2.04]; p = .30) and postoperative infection rate (OR, 0.45 [95% CI, 0.17-1.15]; p = .09) between the groups. Our results suggest that arthroscopic ankle arthrodesis is superior to open ankle arthrodesis alone in the treatment of ankle arthritis based on the overall complication rate, intraoperative tourniquet time, length of the hospital stay, non-union rate and rate to fusion. However, further high-quality randomized controlled trials with appropriate blinding methods are needed to confirm the findings.

Open Ankle Arthrodesis: a Systematic Review of Approaches and Fixation Methods

BACKGROUND

Open ankle arthrodesis (OAA) remains the most widely used operation in end-stage ankle osteoarthritis. However, there is a large variation in terms of approach and fixation methods. The aim of this systematic review was to assess the effect of different approaches and fixation methods on the union rate, complication rate and functional outcome in OAA.

METHODS

A search of the online databases PubMed, Embase, and Cochrane library was performed to identify patients who underwent OAA with screw- and/or plate-fixation.

RESULTS

We identified 38 studies, including 1250 patients (1290 ankles). The union rate was 98% (95% CI 0.95-0.99) for the anterior, 96% (95% CI 0.92-0.98) for the lateral and 96% (95% CI 0.68-1.00) for the combined medial/lateral approach. Screw-fixation achieved an overall union rate of 96% (95% CI 0.93-0.98) and plate-fixation 99% (95% CI 0.96-0.99). The overall complication rate was 14%, 16% and 31% for the anterior, lateral and combined medial/lateral approaches respectively. It stood at 18% for screw-fixation and 9% for plate-fixation. The infection rate was 4%, 6% and 8% for the anterior, lateral and combined approaches respectively. Screw-fixation had an infection rate of 6% and plate-fixation 3%. The postoperative AOFAS scores were 76.8, 76.5 and 67.6 for the anterior, lateral and combined approaches respectively and 74.9 for screw- compared to 78.5 for plate-fixation. These differences did not reach statistical significance.

CONCLUSION

This study, the first of its kind, found little difference in terms of results between approach and fixation method used in OAA.

LEVEL OF EVIDENCE

Level IIa.

Ankle conFUSION: The quality and readability of information on the internet relating to ankle arthrodesis

BACKGROUND

The internet is an important source of information for patients undergoing surgery. Multiple studies have identified inappropriately high reading levels of patient information online. The average reading level in the United States is 7-8th grade. Multiple organisations have recommended that patient information not exceed 6th grade level. This study aims to evaluate the reading levels and quality of information regarding ankle fusion surgery online.

METHODS

Google, Bing and Yahoo were searched (MeSH "ankle fusion", "ankle arthrodesis") and the top 30 URLs analysed. Readability was assessed using an online readability calculator to produce 3 scores (Gunning FOG, Flesch Kincaid Grade and Flesch Reading Ease). Quality was assessed using a HONcode detection web-extension and the JAMA benchmark criteria.

RESULTS

Ninety-eight webpages were identified. The mean Flesch Kincaid Grade level was 9.24 ± 2.33 (95% CI 8.78-9.71). The mean Gunning FOG grade was 10.88 ± 3.1 (95% CI 10.26-11.5). The mean Flesch Reading Ease score was 49.88 ± 14.46 (95% CI 46.98-52.78). 7 webpages were at or below the 6th grade reading level. The mean JAMA score was 1.34 ± 1.32 out of 4 (95% CI 1.07-1.6). 14 websites were HONcode accredited.

CONCLUSION

The overall readability of medical information online is too high for the average patient. Given the important role that health literacy provides in patient reported outcomes, improving the readability and quality of these materials is imperative. Awareness by the general public is essential for them to critically appraise the information they receive online.