Anterior Plate-Supported Cannulated Screw Surgery for Ankle Arthrodesis: Clinical and Radiologic Results in Patients with Trauma-Related End-Stage Ankle Osteoarthritis

Introduction

The unique anatomical structure of the ankle joint provides biomechanical stability and, in terms of articular cartilage, is more durable than other joints in the body [1]. Similar to other joints, any breakdown of the anatomical structure lowers the biomechanical stability of the joint and leads to degenerative osteoarthritis over time [2,3]. Contrary to osteoarthritis of the knee and hip joints, of which only 2–10% are caused by injury, arthritic changes in the ankle are due to trauma in up to 90% of cases [4]. The most common causes of secondary osteoarthritis are traumatic injuries of the ankle, including malleolar fractures, ankle ligament lesions, and tibial plafond fractures [5].

The ankle is the joint most frequently injured during sports activities, with over 300,000 documented injuries yearly in the United States [3]. Ankle sprains had a 15% occurrence rate among more than 4000 military personnel assessed, making ankle sprains the most frequent non-combat-related injury [6]. There is an approximate rate of 52.3 ankle injuries per 1000 instances of sports participation among high school-aged players [7]. The significance of acute cartilage damage in the development of ankle osteoarthritis is especially clear in cases of sprain-related posttraumatic osteoarthritis [3]. The development of posttraumatic ankle osteoarthritis is commonly attributed to chronic changes in joint mechanics, such as malalignment, instability, and incongruity [8].

Posttraumatic ankle osteoarthritis is a progressive, degenerative articular cartilage disease characterized by pain, reduced range of motion, loss of quality of life, and additional disability symptoms [9]. Clinical symptoms of pain and dysfunction typically appear years or even decades after the initial injury [10].

The evaluation of the ankle after traumatic osteoarthritis starts with radiographic imaging, including weight-bearing anteroposterior, mortise, and lateral ankle views [11]. Compared with radiography, computed tomography (CT) offers a more advanced evaluation of the articular surfaces of the ankle joint, especially the subtalar joint. It accurately shows deformities, degenerative changes, and incongruity in the joint [12]. Like CT, magnetic resonance imaging (MRI) offers multiplanar imaging, which provides a more detailed representation of the intricate anatomy of the ankle and subtalar joints. MRI is the preferred imaging technique for patients with chronic ankle pain because it can detect ligamentous damage, subchondral bone edema, and cartilage abnormalities [13].

Before deciding on the surgical treatment of end-stage posttraumatic ankle osteoarthritis, the underlying etiology should be defined thoroughly since, in contrast to primary osteoarthritis, secondary osteoarthritis accounts for the majority of symptomatic osteoarthritis in adults [3]. The recent treatment of ankle joint osteoarthritis with arthrodesis surgery is guided by basic arthrodesis principles, and regarding ankle arthrodesis surgery, both open and closed approaches for the resection methods of the chondral structure are well described [14,15]. Cannulated compression screws, plate systems, arthrodesis nails, and external fixators are used as fixation methods in arthrodesis surgery [15–17]. The surgeon decides on the technique to be used in the arthrodesis surgery based on a detailed preoperative evaluation considering the condition of the soft tissue around the joint, bone quality, and deformity.

Complications such as soft tissue problems, delayed union, nonunion, and malalignment are common in the postoperative period [18]. The success of the surgery is mainly affected by soft tissue problems in the early postoperative period; however, nonunion and malalignment often develop in the long term and reduce the success rate. The success of ankle arthrodesis depends on the surgical technique used [19].

In both clinics, the combination of cannulated screw and anterior plating techniques is frequently used in arthrodesis surgery for end-stage posttraumatic ankle osteoarthritis. This retrospective study included 31 patients with posttraumatic ankle osteoarthritis, from 2 centers in Türkiye, treated with anterior tibiotalar arthrodesis using an anterior plate and cannulated screw fixation, between January 2018 and July 2022, with 6-month follow-up.

Material and Methods

ETHICS APPROVAL:

The Clinical Research Ethics Committee of the Adana City Training and Research Hospital issued ethical approval, decision number 2345, on December 29, 2022.

DATA COLLECTION AND STUDY DESIGN:

In this bi-center study, we retrospectively reviewed the digital records of 66 patients with end-stage ankle osteoarthritis who were treated with ankle arthrodesis at Health Sciences University, Adana City Training and Research Hospital and Kütahya Evliya Çelebi Training and Research Hospital, between January 2018 and July 2022. The files of patients under 18 years of age, with less than 6 months of follow-up, and those who underwent arthrodesis surgery following tumor surgery were excluded. The study was conducted with a total of 31 patients who underwent arthrodesis surgery using 2 or 3 cannulated screws and anterior plating techniques for end-stage ankle osteoarthritis with a minimum follow-up period of 6 months.

The data on age, gender, comorbidities, smoking, operative technique, graft use, complications, union characteristics, visual analog scale (VAS), and Maryland functional scoring results were recorded at the preoperative and postoperative 6-month visits.

RADIOLOGIC AND CLINICAL EVALUATION:

The study’s patients were evaluated radiographically using X-ray imaging at the initial evaluation, and preoperative CT was used to assess the bone stock. Specifically, weight-bearing radiographs were obtained for both initial examination and postoperative evaluation.

In clinical follow-up after surgery, the presence of calluses in the 3 cortices in the anteroposterior and lateral direct radiographs taken at follow-up was considered an indicator of complete union. Union in the first 3 months postoperatively was considered successful, union between 3 and 6 months was considered delayed union, and the absence of signs of union after the sixth month was considered nonunion.

Regarding the assessment of VAS, a numerical classification was made on a scale of 0–10, with the worst pain level scored as 10 points. The Maryland foot score was evaluated for 3 main items: pain (5–45), function (0–50), and range of motion (0–5) [20].

OPERATIVE TECHNIQUE:

All patients with end-stage ankle osteoarthritis underwent surgery under spinal anesthesia in the supine position with a 300-mmHg pressure tourniquet. The ankle capsule was accessed after a skin incision just lateral to the tibialis anterior tendon, and the joint capsule was opened longitudinally. The joint was exposed entirely by widening the exposure. Curettes and osteotomes were used to resect chondral structures on the articular surfaces of the tibia, fibula, and talus to preserve bone structure. Bone contact in the optimal position for arthrodesis [in neutral flexion, slight (0 to 5 degrees) valgus angulation, and approximately 5 to 10 degrees of external rotation] was checked under radiographic control, and fixation was achieved with 2 or 3 cannulated screws sized 6.5 mm, depending on stability.

The angle of insertion of the cannulated screws was adjusted by targeting the middle or posterior part of the joint as much as possible to increase the grip of the screws. After cannulated screw fixation, a 3.5-mm reconstruction plate was bent to match the arthrodesis angle and was placed anteriorly to the joint. The plate, with a locking screw, was first fixated to the talus and then fixated to the tibia with a non-locking screw, followed by fixation to the talus with an oblique long-locking screw. Then, 2 locking screws were placed in the tibia, and the fixation procedure was finalized. Finally, the contacting surfaces of the fixation were assessed under fluoroscopy, and an autograft from the iliac wing was applied if necessary. The joint capsule, subcutaneous tissues, and skin were closed, respectively. A splint was applied to the patient at the end of the operation.

POSTOPERATIVE MANAGEMENT AND CLINICAL FOLLOW-UP:

Postoperative wound care was performed by opening only the dressing area without removing the short leg splints. Patients were mobilized with double crutches or walkers such that the injured ankle was non-load bearing. Patients with no wound site problems were discharged between 48 and 72 hours postoperatively.

At the first follow-up visit in the third postoperative week, sutures were removed, and the plaster splints were replaced with fixed-angle orthoses. In the sixth postoperative week, patients were mobilized in a controlled manner with as much load as they could tolerate.

STATISTICAL ANALYSIS:

SPSS 23.0 for Windows was used for statistical analysis. Descriptive statistics of the evaluation results were given as numbers and percentages for categorical variables, such as mean, standard deviation, median, minimum, and maximum for numerical variables. Independent t-test, paired-sample t-test, and one-way ANOVA were used for normally distributed parameters. Mann-Whitney, Kruskal-Wallis, and Wilcoxon signed-rank tests were used for non-normally distributed parameters. Differences between the rates of categorical variables in independent groups were analyzed using Chi-Square and Fisher’s exact tests. P<0.05 was set as the statistical significance level in all tests.

Results

DEMOGRAPHIC CHARACTERISTICS OF PATIENTS:

The characteristics of the 31 patients (mean age, 55.5 years; range 19–82 years; 13 men, 18 women) included in the study are given in Table 1.

EARLY/LATE COMPLICATIONS AND CLINICAL OUTCOMES:

During the clinical follow-up of the patients following arthrodesis surgery, 2 had early complications (wound necrosis and infection), and 5 had late complications (implant failure, nonunion, delayed union). Except for the patient with the implant failure, the remaining cases who encountered complications were smokers. The treatment of the implant failure included a revision surgery using the same operation technique with autografting.

Of the 2 patients with early-period complications, the patient with wound necrosis smoked 1.5 packs of cigarettes per day, and was treated with local superficial debridement and wound care. The second patient with wound infection was also a smoker (1 pack/day) and had diabetes mellitus. In addition to the infection, this patient also developed nonunion. Union was, however, achieved after the removal of the implants, wound debridement, antibiotic treatment for the causative agent, diabetes regulation, and Ilizarov external fixator application.

The other patient with nonunion was also a smoker (2.5 packs/day). Union was achieved following a smoking cessation treatment program, and revision surgery was performed with cannulated screws and anterior plating using a surgical technique with autografting from the iliac wing. The 2 patients with delayed union were also smokers (2 packs/day), and union was observed between the fifth and sixth months.

The characteristics of the patients with complications are given in Table 2. The prolonged duration in union formation was statistically significant among the cases with complications (P=0.002). The smoking rate was significantly higher in patients encountering complications (P=0.001). Among cases with complications, the VAS and Maryland scores recorded in the postoperative sixth month were significantly higher (P=0.027 and P=0.018, respectively).

Discussion

In the literature, the average union rate following foot arthrodesis using different surgical techniques, including screw fixation, is 96%, ranging between 87 and 100 percent [18,21]. In our study, we achieved a rate of 93.5%.

In our technique, we aimed to provide a tighter grip during the arthrodesis, to counter loosening forces, by stabilizing inversion and eversion movements through cannulated screws installed laterally and medially, and by disabling flexion and extension movements through anterior plate fixation.

Monteagudo et al proposed that following isolated arthrodesis of the ankle, the tensile force of the gastrocnemius may develop a gradual shift of the subtalar joint towards the varus, thus limiting the compensating movements in the midtalar joint. Therefore, they suggested stabilizing the subtalar joint in isolated ankle arthrodesis cases [22].

On the contrary, in a cadaveric study, Henry et al showed changes in the kinematics of the talonavicular joint following subtalar arthrodesis. They highlighted the subtalar joint’s importance [23]. Currently, we prefer not to include an intact subtalar joint in an arthrodesis operation, and in our study, we did not perform subtalar join arthrodesis on patients with isolated ankle arthrodesis.

In a biomechanical study comparing the results from cannulated screws with anterior plate strengthening to cannulated screws alone, Tarkin et al demonstrated that the addition of anterior plates to the cannulated screws resulted in 3.5, 1.9, and 1.4 times more resistance in the sagittal, coronal, and axial planes, respectively [24]. Citing the Tarkin et al report, further studies have been conducted, and successful results of ankle arthrodesis have been reported, in which single and dual plates were used. In the studies of Steginsk et al and Flint et al, customized plates were used on the anterior ankle [14,25]. The above-mentioned plates are difficult to access and expensive. In our study, the plates used were relatively inexpensive, easy to access, and shapeable.

Bone stock deficiency is a major problem in all joint arthrodesis cases. Horisberger et al emphasized the importance of the time interval between ankle injury and the date of painful end-stage ankle osteoarthritis, when ankle arthrodesis is indicated. When this time interval is prolonged, it has been associated with a decrease in bone stock [5].

In ankle arthrodesis, talus necrosis results in bone stock failure, especially in patients with large necrosis in the talus, and in such cases providing joint arthrodesis becomes extremely difficult. Nevertheless, in cases of talus absence, there are custom-made plates designed explicitly for arthrodesis union, but high nonunion rates have been reported in studies conducted with specially designed cage implants [26].

In our study, there were 8 patients with insufficient talus bone stock. We succeeded in these patients by extending the distal part of the plate towards the navicular and expanding the arthrodesis region (Figure 1).

We used 3.5-mm reconstruction plates with holes for locked and unlocked screws. The technique included the plating phase following fixation using cannulated screws; the ankle is slightly forced to dorsiflexion. After bending the plate appropriately, it is placed anteriorly, and an unlocked screw is installed in the tibia and navicular bone, providing increased compression on the anterior of the arthrodesis region. The unlocked screw also tightens the plate onto the anterior tibia and reduces the risks of implant irritation and failure (Figure 2).

The advantages of the technique include but are not limited to: sufficient compression in cases that cannot achieve sufficient compression with cannulated screws (eg, patients with osteoporosis), no requirement for a separate incision for plating, and the provision of enough exposure area for debridement and resection of the chondral surfaces.

A meta-analysis conducted by Patel et al showed that smoking and the male gender increase the rate of wound problems [27]. Studies have demonstrated that smoking increases the rate of nonunion incidents in fracture cases by 1.6, particularly among arthrodesis cases, in which the rate increases by 3.75 [28,29].

Two of our patients required revision surgery. The first patient was a heavy smoker (2.5 packs per day). Smoking cessation treatment was applied 3 weeks before the revision, and union was achieved. The second patient was a smoker, at a rate of 1.5 packs per day, who developed wound necrosis. The thin subcutaneous fat tissue and the increased retraction duration, resulting in impaired tissue perfusion, were possible causes of wound necrosis. The necrosis of the wound was removed by superficial debridement. Nevertheless, trying to avoid similar problems, we preferred to use Farabeuf retractors instead of Hohmann retractors, aiming to decrease the pressure on the incision line. We strongly recommend paying attention to this detail.

Union problems may emerge in patients with uncontrolled diabetes, and keeping HbA1c levels below 7% preoperatively has been shown to reduce union complications [30]. The diabetic patient who required revision surgery developed wound infection and nonunion problems. The implants were removed and fixated using Ilizarov external fixators, resulting in a successful union. In addition, Horisberger et al emphasized the importance of the time interval between ankle injury and the date of painful end-stage ankle osteoarthritis when ankle arthrodesis is indicated.

The study’s limitations include the retrospective design, the low number of participants, the lack of a control group, and the relatively short follow-up duration. A large, randomized, prospective examination is needed to assess posttraumatic end-stage ankle osteoarthritis following specific types of injuries.

Conclusions

Since most patients with end-stage ankle osteoarthritis are suffering from a chronic condition, the basic expectation is to mobilize painlessly by plantigrade pressure. Our study has shown that cannulated screw fixation, strengthened with a common and easy-to-supply anterior reconstruction plating technique, had high fixation power and good functional results in patients with end-stage posttraumatic ankle osteoarthritis.