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Ankle Fracture Fixation Using A Novel Flexible Intramedullary Fibular Nail and Alignment Guide Affording Syndesmotic Re-alignment along the Centroidal Axis
Reported advantages of ankle fracture fixation using intramedullary fibular (IMF) nails over traditional plates/screws include: earlier weightbearing, reduced wound complications, better union rates, and the absence of prominent hardware. The purpose of present case series was to assess the early clinical and radiographic outcomes of patients who underwent ankle fracture fixation using a novel, flexible IMF nail affording syndesmotic realignment along the centroidal axis. Demographic, clinical, and radiographic data were recorded for all patients who underwent after ankle fracture fixation using a novel, flexible IMF with syndesmotic realignment between May 2021 and May 2022, and who were at least 6 months postoperative. Toe-touch weightbearing was permitted immediately after surgery, protected weightbearing (PWB) at postoperative week 2, and weightbearing as tolerated in a brace at week 6. Formal physical therapy commenced at postoperative week 8. Radiographs were assessed preoperatively, and at 2, 6, 12, 24, and 48 weeks postoperative. Twenty-three ankles with a mean follow up of 6.9 (range, 6 to 11) months were included. Overall, painless weightbearing without any residual swelling and stiffness was documented in all but 1 patient, and mean time to union was 11.5 (range, 6 to 24) weeks. Eighteen ankles (78%) showed complete union at 12 weeks postoperative, while 5 (AO/OTA B1.2, B2.1/3, B3.1/3) showed progressive signs radiographic union without clinical symptoms; all progressed to union by 24th weeks postoperative. Reduction and alignment maintenance was observed in all ankles during the most recent follow-up, and no complications/reoperations related to the IMF nail were recorded. A total of 6 complications unrelated to the IMF nail were recorded, and 2 ankles required reoperation. A history of tobacco was associated with delayed union (p=0.02). Short-term follow-up for ankle fractures fixated using a flexible, IMF nail with concurrent syndesmotic realignment along the centroidal axis showed painless weightbearing and complete radiographic union, without any complications/reoperations related to the IMF; irrespective of fracture morphology.
Over the past decade, ankle fracture fixation using intramedullary fibular (IMF) nails has continued to gain popularity, and acceptance. Previous authors have shown earlier time to weightbearing using the load sharing construct(s), reduced wound healing complications (delayed wound healing, dehiscence, and infection), better union rates, and an absence of prominent hardware necessitating removal
Intramedullary Fixation Versus Plate Fixation of Distal Fibular Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies.
. Therefore, despite the initial learning curve and higher cost upfront, ankle fracture fixation using IMF nails has been shown to afford equivalent clinical outcomes compared to traditional open reduction internal fixation (ORIF) using plates and screws, with a shorter postoperative convalescence period, and an overall lower cost of healthcare delivery
Intramedullary Fixation Versus Plate Fixation of Distal Fibular Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies.
Court-Brown CM. A prospective randomised controlled trial of the fibular nail versus standard open reduction and internal fixation for fixation of ankle fractures in elderly patients.
Intramedullary fibular nailing has historically however, been relegated to, and reserved for geriatric fractures, and patients with multiple medical comorbidities; while traditional ORIF of using plates and screws followed by prolonged periods of postoperative non-weightbearing (NWB), especially in the setting of concomitant syndesmotic injury has remained common practice. Given the published advantages of IMF nailing over traditional ORIF using plates and screws, it is important to ascertain whether traditional fixation followed by 6-8 weeks of NWB postoperatively is actually warranted in ankle fractures with concomitant syndesmotic injury; routinely practiced by surgeons for fear of inadequate fracture reduction and fracture displacement.
“Flexthread” (Conventus-Flower Orthopedics LLC., Horsham, Pennsylvania) is a straight IMF nail designed for ankle fracture fixation with/without concurrent syndesmotic stabilization. The load sharing device comes in three diameters (3.5mm blue, 4.5mm gold, and 5.5mm green), two lengths (130mm, and 180mm), and is uniquely designed to “flex” during insertion, owing to its proprietary titanium alloy, with self-tapping threads proximally, and 1 to 3 polyaxial 2.7mm interlocking screws distally to engage the fibula (Fig 1). Two neutral, un-angled (i.e. not 20 to 30 degrees anteriorly positioned) syndesmotic stabilization slots are available for fixation at approximately 2 and 4 cm proximal to the ankle joint, and an outrigger arm can be attached to the nails insertion guide to allow up to 10m of compression or distraction; exceeding the capability of other IMF device's currently on the market (Fig 2).
Figure 1“Flexthread” IMF nail is available in three diameters (3.5mm, 4.5mm, and 5.5mm) and two lengths (130mm, and 180mm), with self-tapping threads proximally, 1 to 3 polyaxial 2.7mm interlocking screws distally, and 2 neutral, un-angled (i.e. not 20 to 30 degrees anteriorly positioned) syndesmotic stabilization slots for fixation at approximately 2 and 4 cm proximal to the ankle joint line.
The flexible IMF nail design is further differentiated from other IMF nails by three key features. Firstly, after placement of either a 2.0mm diamond/trocar tipped wire and reaming, the straight IMF design facilitates an ease of entry, while mitigating the risk of malreduction observed with laterally bent nails placed too medially at the entry point. Bent nails placed too medially bow out the distal fibula while simultaneously tensioning the anterior and posterior talofibular ligaments; resulting in lateral subluxation of the talus and diastasis between the tibia and fibula proximally in the presence of syndesmotic disruption (Fig 3). The iatrogenic malreduction introduced from too medial an entry cannot be manually reduced or corrected without complete removal of the IMF. Replacement of a guidewire more laterally and re-reaming however compromises the bone stock of fibula distally, necessitating the surgeon in some cases abandon IMF nailing all together in leu of traditional ORIF using plates and screws.
Figure 3IMF entry placement too medially resulting in bowing out of the distal fibula and simultaneous tension on the anterior and posterior talofibular ligaments resulting in lateral subluxation of the talus and diastasis between the tibia and fibula proximally in the presence of syndesmotic disruption. Permission for image granted from outside surgeon/institution.
Secondly, the flexible IMF nails self-tapping threads proximally engage the fibula without dependance on fixation deployment which has been previously shown to malfunction, and without the need for additional hardware placement; mitigating the risk of superficial peroneal nerve irritation or injury. Distally, polyaxial screws interlock directly with the IMF itself, rather than with the cortical surface of the fibula as in other IMF nail devices currently on the market (Fig 4a-b). This mitigates the risk of hardware failure or loosening seen with other designs, and lends itself particularly useful in cases of poorer bone quality and osteoporosis (Fig 5.).
Figure 4Polyaxial screws interlock directly with the Flexthread IMF distally rather than with the cortical surface of the fibula as in other IMF nail devices on the market.
Figure 5Hardware loosening of syndesmotic screws placed quadricortically in another IMF nail design for fracture fixation in patient with osteoporotic bone.
Finally, 2 neutral, un-angled (i.e. not 20 to 30 degrees angled from the coronal plane) syndesmotic stabilization slots are available for fixation, when indicated. The neutral, un-angled slots allow surgeons to determine and place syndesmotic fixation along each patients ideal trajectory; termed the “centroidal axis”, at approximately 2 and 4cm proximal to the ankle joint. Over the past decade, studies have delineated this ideal trajectory for syndesmotic fixation first described by Kennedy et al
A computed tomography evaluation of two hundred normal ankles, to ascertain what anatomical landmarks to use when compressing or placing an ankle syndesmosis screw.
; i.e. the trajectory that maintains alignment during fixation placement, without introducing a secondary iatrogenic malreduction force. The centroidal axis has been shown to vary between patients and ankles, but is accurately approximated intraoperatively using the “Center-Center” technique
(Fig 6). Angled syndesmotic slots on other nail guides preclude, rather than facilitate, optimal syndesmotic reduction and alignment.
Figure 6Intraoperative image depicting internal rotation of the limb (“Center- Center” technique) to align the fibula centrally within the tibia after insertion of the Flexthread IMF nail
With consideration to the above, the purpose of present retrospective case series was to assess early clinical and radiographic outcomes of patients who underwent ankle fracture fixation using a novel flexible IMF nail with concurrent syndesmotic stabilization along the centroidal axis.
Materials and Methods
Study Design
Using an institutional review board approved database, prospectively collected data was assessed for patients who underwent ankle fracture fixation with/without syndesmotic stabilization and who were permitted early postoperative WB between May 2021 to May 2022 at a single institution (Dallas Orthopedic and Shoulder Institute, Sunnyvale, TX), by a single foot and ankle fellowship trained surgeon (CJR). Current Procedural Terminology codes 824.2 to 824.9 were used for identification and were cross referenced with the International Classification of Diseases, ninth revision, diagnosis codes 250.00 to 250.93 and medical record to ensure accuracy. Exclusion criteria included: skeletally immature patients, open fractures/polytrauma, fractures secondary to Charcot osteoarthropathy, non-ambulatory status before injury, and less than 6 months follow-up. Twenty-five patients made the inclusion criteria, the rest were excluded.
Surgical Technique
All ankles underwent preoperative computed tomography to assess posterior malleolar (PM) fracture morphology/identify any intercalary fragment(s), as well as subsequent intraoperative arthroscopy. Ankle arthroscopy was performed to lavage the joint of proinflammatory cytokines and fracture hematoma, assess for osteochondral lesions of the talus/tibia, and discern the presence/absence of syndesmotic injury. In cases utilizing non-invasive ankle distraction, the distractor was released prior to assessment of the syndesmosis to prevent any ligamentous tension distally from causing a false negative assessment; gravity distraction is the authors preferred method for arthroscopy assisted ankle fracture fixation.
Following arthroscopy, malleolar fracture reduction/fixation was performed in the following order; posterior, medial, lateral. Intercalary fragments were excised in all cases prior to PM fracture fixation. Fractures involving the posterior-lateral tibia plafond were fixated with a single screw placed from posterior to anterior, while those involving the posterior lateral and medial tibial plafond were plated. Medial malleolar fractures involving the anterior colliculus were secured with a single 4.0mm screw, 45mm in length, while those involving the entire malleolus were plated.
Finally, fibular length, rotation, and angulation was restored using a Hintermann distractor, point to point reduction clamp(s), or a combination thereof (Fig 7a-d). The authors preferred Hintermann distractor is large with closed arms, a design providing the appropriate amount of strength and distraction for the lateral malleolus (Fig 8). Care must be taken to place the Kirschner wires as close as possible on opposing ends of fracture, with placement directed toward either the anterior, or posterior half of the fibula to allow room for the entry wire (diamond or trocar tipped) of the IMF to pass posteriorly or anteriorly, respectively (Fig 9a-d). After initial placement of the IMF, the limb is internally rotated to the “Center-Center” position and the holes are aligned neutrally by rotating the nail (Fig 10a-c). While maintaining the position, the out-rigger guide is then attached, the syndesmosis is manually reduced; two provisional pins are placed into the syndesmotic stabilization sots across the fibula and tibia to maintain the rotation of the IMF, as well as the syndesmosis realignment. Syndesmotic reduction is then verified by extending the anterior-lateral portal of the ankle arthroscopy incision 1-2 cm proximal, for direct palpation of distal tibiofibular congruence (Fig 11). This avoids difficulties with assessment of iatrogenic malreduction using fluoroscopy. Two polyaxial screws are then inserted and seated flush with the nail, followed by placement of two syndesmotic fixation devices along the centroidal axis. Type of fixation for the syndesmosis was determined at the discretion of the operating surgeon; most cases involved insertion of 2 flexible fixation devices. The most distal fixation was always placed first, followed by fixation proximally. The end result in most cases, was 4 stab incisions for the lateral malleolus, 1 stab incision each for the posterior and medial malleolus, and 2 incisions for ankle arthroscopy; a total of 6-8 stab incisions, depending on the number of fractures morphology (Fig 12a-b).
Figure 7Restoration of the length, rotation, and angulation of the fibula using a (A-B) Hintermann distractor, or (C-D) point to point reduction clamp.
Figure 8Intraoperative image depicting placement of a large Hintermann distractor with closed arms in the anterior, or posterior half of the fibula to allow of guidewire placement, reaming, and insertion of the Flexthread IMF.
Figure 9Intraoperative image depicting placement of a Hintermann distractor and Kirschner wires as close as possible on opposing ends of fracture, with placement directed toward the anterior half of the fibula to allow room for the entry wire, reamer, and Flexthread IMF nail posteriorly.
Figure 10After initial insertion of the Flexthread IMF nail, the limb is (A) internally rotated to the “Center-Center” position such that the fibula aligns centrally within the tibia. While holding the limb, the IMF nail itself is then rotated until the syndesmotic holes are perfectly aligned, and the outrigger guide is attached. Manuel reduction of the syndesmosis is then performed followed by (B) provisional fixation using two K-wires. (C) With the limb internally rotated into the “Center-Center” position, the K-Wires are parallel with the operating room table.
Figure 11Syndesmotic realignment is then verified by direct palpation of the distal tibiofibular congruence anteriorly. This technique avoids the inherent subjectivity and difficulties associated with intraoperative assessment of syndesmotic alignment.
Figure 12(A) Intraoperative fluoroscopy image depicting tri-malleolar ankle fracture fixation with syndesmotic realignment along the centroidal axis. Intraoperative images showing the (B) lateral and medial (C) stab incisions associated with the authors minimally invasive, arthroscopy assisted, percutaneous ankle fracture fixation surgical technique. The end result in most cases was 4 stab incisions for the lateral malleolus, 1 stab incision each for the posterior and medial malleolus, and 2 incisions for ankle arthroscopy; a total of 6-8 small incisions, depending on fracture morphology.
Postoperatively, toe-touch weightbearing was permitted immediately, protected weightbearing in a controlled ankle motion (CAM) boot at 2 weeks, and weightbearing as tolerated in an ankle brace at 6 weeks. Formal physical therapy was commenced at postoperative week 8.
Study Population
A total of 25 patients underwent ankle fracture fixation with/without syndesmotic stabilization and were permitted early postoperative WB. The study included 7 men and 18 women, with 9 right-sided surgeries and 16 left sided; mean follow up 6.8 (range, 6 to 11) months. The mean age was 51 years (range, 23-82), with an average BMI of 34.2 (range, 22.1-53.3). Four patients were diabetic (16%), and 5 had a history of previous tobacco use (20%). Demographic factors are summarized in Table 1.
Overall, 11 (44%) ankle fractures were tri-malleolar, 11 (44%) were bi-malleolar, and 3 (12%) were uni-malleolar. According to the AO/OTA classification, 1 fracture was type 44A2.3 (4%), 1 type 44B1.2 (4%), 8 were type 44B2.1 (32%), 8 type 44B2.3 (32%), 2 AO/OTA type B3.1 (8%), and 4 type AO/OTA B3.3 (16%). According to the Lauge Hansen classification, 1 fracture was pronation external rotation stage 4 (4%), 22 were supination external rotation stage 4 (88%), 1 supination external rotation stage 3 (4%), and 1 supination adduction stage 2 (4%). Fracture classifications are also summarized in Table 1.
Of the 25 fractures, 15 (60%) underwent ankle arthroscopy, 6 (24%) had an OLT that was repaired, and 24 (96%) required syndesmotic stabilization. OLT were all repaired with allograft cartilage, while syndesmotic stabilization was performed in all but one case with two forms of fixation along the centroidal axis; single dynamic fixation device (1, 4%), two dynamic fixation devices (13, 52%), single dynamic fixation device with a fully threaded tricortical screw proximally (4, 16%), and two fully threaded screws (6, 24%). Reduction technique(s) varied based on the fibular fracture morphology; 12 (48%) were reduced using a point to point reduction clamp, 8 (32%) were reduced with a hintermann distractor, 2 (8%) utilized both a clamp and hintermann, and 3 (12%) did not require reduction after concurrent fracture fixation. Nineteen IMF nails were 4.5mm in diameter, 5 (20%) were 3.5mm, and 1 (4%) was 5.5mm diameter; all were 180mm in length. A majority of cases were completed in under 120 minutes (23, 92%).
Clinical & Radiographic Assessment
Medical records and charts were reviewed. Concurrent procedures performed at the time of fixation, union rate, time to union, complications (medical/surgical), and reoperations were recorded. Weightbearing ankle anteroposterior (AP), mortise (MO), and lateral radiographs are routinely obtained postoperatively at 2, 6, 12, 24, and 48 weeks. Assessments at each temporal interval were assessed for evidence of fracture line, reduction maintenance, and hardware failure. Fracture union was defined as
Intramedullary Fixation Versus Plate Fixation of Distal Fibular Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies.
no tenderness with palpation over the surgical sites. Radiographs were also assessed for fracture specific complications including delayed union, non-union, malunion, hardware failure, and loss of reduction. Delayed union was defined as fracture union occurring more than 12 weeks from the time of fixation with clinical symptoms, and malunion as union with >2mm of anatomic step-off. Computed tomography (CT) was obtained when there was concern for symptomatic delayed/non-union after the 12th postoperative week.
Statistical Analysis
Descriptive statistics were used to report demographic data, and complications. Comparisons between clinical and radiographic parameters was performed by a Wilcoxon Signed Rank Test. Fishers Exact Test or Logistic Regression was used to identify associations between any predictors and outcomes. All statistical analysis was performed using SAS 9.4 software, and all tests were considered significant with an alpha level of 0.05.
Results
Clinical Outcomes
A total of 25 patients underwent ankle fracture fixation using a flexible IMF nail with concurrent syndesmotic stabilization along the centroidal axis. Overall, no complications (delayed wound healing, dehiscence, infection, incisional numbness, etc.) or hardware related issues (prominence, irritation, or incisional numbness) related to the IMF nail were recorded at a minimum of 6 months postoperative. Six (24%) complications unrelated to the IMF nail in 6 patients were recorded, and 2 ankles (8%) required reoperation. A history of diabetes trended toward an increased risk of reoperation, and both ankles requiring revision were in diabetic patients with borderline neuropathy on 5.07gm semmes seinstein monofilament (SWM) testing. Complications included: delayed wound healing (3 ankles, 12%) of the anteromedial ankle arthroscopy portal (2 ankles, 8%), or medial malleolar fracture fixation incisions (1 ankles, 4%), medial malleolar plate hardware irritation (1 ankle, 4%), an infected non-union of the medial malleolus (1 ankle, 4%), and failure of the medial malleolar fixation (1 ankle, 4%) secondary to incidental trauma. Both ankles that warranted reoperation for complications un-related to the IMF nail (infected medial malleolar non-union, and medial malleolar hardware failure) were successfully revised in a staged fashion to arthrodesis; both were excluded from the remaining analysis.
The two most common subjective complaints reported postoperatively were periodic swelling and stiffness. At 6 and 12 weeks postoperative, all 23 patients were transitioned into, and then out of, a lace up ankle brace. Mean verbal analogue scale (VAS) scores for pain at 6 and 12 weeks postoperative were 4 and 2, respectively. At 6 months postoperative, painless weightbearing without residual swelling and stiffness was documented in all but 1 patient, whom continued to report episodic swelling with discomfort along the medial ankle secondary to hardware irritation.
Radiographic Outcomes
Twenty-three patients that underwent ankle fracture fixation using a flexible IMF nail with concurrent syndesmotic stabilization along the centroidal axis were included for the radiographic analysis. Overall, union with reduction and alignment maintenance, and the absence of hardware failure was observed in all cases (23 ankles, 100%). Mean time to union was 11.5 (range, 6 to 24) weeks, approximately 3 months. Eighteen ankles (78%) showed complete radiographic union at 12 weeks postoperative, while 5 ankles, showed incomplete, but progressive signs of radiographic healing. In all 5 ankles, painless weightbearing and the absence of tenderness with palpation over the incision site was recorded, despite incomplete resolution of the fracture line. Therefore, transition out of the ankle brace was not delayed, nor was a CT obtained. A history of tobacco was associated with delayed union (p=0.02). Additionally, lateral malleolar fractures morphology in all 5 cases was multi-fragmented/comminuted, versus the more common spiral/oblique/transverse fracture pattern(s). Twelve ankles (52%) healed primarily without callus formation, and 11 ankles (48%) healed with observable callus formation on radiographs. No non-unions or hardware related complications (loosening, migration, or breakage) were recorded. Radiographic data is summarized in Table 2.
To the best of the authors knowledge, the present study is the first to assess outcomes for ankle fractures fixated using the flexible, “Flexthread” IMF nail, and it's guide affording syndesmotic realignment along the centroidal axis. For this purpose, demographic, clinical and radiographic outcome data for 25 patients that underwent minimally invasive, arthroscopy assisted, percutaneous IMF nailing using Flexthread with concurrent syndesmotic realignment along the centroidal axis, and whom were permitted immediate toe-touch weightbearing were assessed at a minimum of 6 months postoperative. Two patients who warranted reoperation for complications unrelated to the IMF were excluded from the final assessment; 23 patients were included.
Overall, Flexthread survivorship was 100% at a mean of 6.9 months follow-up. No documented failures of the flexible IMF, or complications/reoperations related to the nail were recorded; rates which compare favorably to other IMF nails, as well as traditional ORIF using plates/screws. Overall, painless weightbearing without any residual swelling or stiffness was documented in all but 1 case during the most recent follow-up. During the index surgery for that case, a large 2-part posterior malleolar fracture extended medially with involvement of both the anterior/posterior colliculi, necessitating plate fixation posteriorly and medially, respectively. Hardware removal was recommended to alleviate the irritation medially, the patient was not undergone reoperation.
During the most recent follow-up, complete radiographic union with reduction and alignment maintenance was observed for all cases (23 ankles, 100%); mean time to union was approximately 3 months. Twelve lateral malleolar fractures (52%) healed primarily without callus formation (Fig. 13a-b), while 11 (48%) healed secondarily with observed callus (Fig 14a-b). The latter was observed in cases of multi-fragmented/comminuted lateral malleolar fracture morphology's; 5 (AO/OTA B3.3, B3.1, B2.3, B2.1, B1.2) of which, had not fully healed on radiographs at 12 weeks postoperative. Nonetheless, CT scan were not obtained for the 5 ankles given the inherent stability afforded by the load sharing construct, and with consideration to the reported painless weightbearing and the absence of any tenderness on palpation; transition out of the lace up ankle brace at 12 weeks postoperative was not delayed either following the completion of formal physical therapy. At 6 months postoperative, no observable fracture line was present in any of the 5 ankles, and no difference was identified between the reported VAS for pain scores. No cases of symptomatic delayed/non-union or hardware related complications (loosening, breakage, migration) were recorded. However, as shown in previous research, a history of tobacco was associated with delayed union (p=0.02).
Figure 13Postoperative weightbearing radiographs depicting primary healing of a fixated ankle fracture, ie without callus formation, A) AP view, and B) Lateral view.
Figure 14Postoperative weightbearing radiographs depicting secondary healing of a fixated ankle fracture, ie with callus formation, A) AP view, and B) Lateral view.
No complications directly related to the flexible IMF nail were recorded. However, 6 (24%) complications unrelated to the IMF nail in 6 ankles were recorded, and 2 ankles (8%) required reoperation. The unrelated complications included delayed wound healing (3 ankles, 12%), hardware irritation medially from a hook-plate (1 ankle, 4%), an infected medial malleolar non-union (1 ankle, 4%), and failure of medial malleolar fracture fixation (1 ankle, 4%) secondary to accidental trauma. Delayed wound healing is a common complication after the fixation of ankle fractures, and all 3 ankles healed with local wound care without further complication.
Two ankles ultimately required reoperation (2 ankles, 8%) for complications unrelated to the IMF. Both patients had a history of poorly controlled diabetes, which was identified as a risk factor for reoperation. In both cases, borderline neuropathy was documented preoperatively after assessment with 5.07gm SWM. However, tibiotalocalcaneal arthrodesis, the authors preferred fixation method for neuropathic ankle fractures was not performed at the index surgery, and neuropathy progression was documented in both cases, resulting in new onset charcot osteoarthropathy (COA) in 1 ankle during the early postoperative period following incidental trauma. Although COA failure was observed medially, without any observable breakage or loosening in the Flexthread IMF nail, the author advises against use of IMF nails for ankle fracture fixation in diabetics with any signs of neuropathy (borderline, early or late); without exception. Both ankles were successfully revised in a staged fashion to tibiotalocalcaneal arthrodesis using a retrograde intramedullary nail and external circulator fixator (Fig. 15a-d). No patients required a below the knee amputation.
Figure 15Postoperative radiographs depicting medial ankle fracture fixation failure secondary to new onset COA following incidental trauma (slip and fall down stairs), A) AP view and B) Lateral view. Postoperative radiographs following reoperation and conversion to TTC arthrodesis using an IM nail and external circular ring fixator, C) AP view and D) Mortise view.
Recent meta-analysis/systematic reviews by Tas et al., and Jordan et al., add to the growing body of evidence showing equivalent clinical and radiographic outcomes, with less postoperative complications and reduced convalesce period for IMF nailing of ankle fractures compared to traditional ORIF with plates/screws
Intramedullary Fixation Versus Plate Fixation of Distal Fibular Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies.
. Moreover, despite the steeper initial learning curve, and higher upfront cost, IMF nails have also been shown to have an overall lower cost to the healthcare system, as hardware prominence and irritation with plates/screws prompting return to the operating room is not common after fixation with IMF nails
Court-Brown CM. A prospective randomised controlled trial of the fibular nail versus standard open reduction and internal fixation for fixation of ankle fractures in elderly patients.
. The authors rationale for performing minimally invasive, arthroscopy assisted, percutaneous fixation of most ankle fractures (excluding diabetic ankle fractures with borderline/established neuropathy) using an IMF nail with concurrent fixation is as follows: 1) gold standard assessment of the syndesmosis/deltoid ligaments, 2) evacuation of proinflammatory cytokines/hematoma, 3) evaluation of articular cartilage, 4) minimal soft tissue dissection with less postoperative complications (delayed wound healing, dehiscence, infection, hardware irritation), and 5) an earlier time to weightbearing (load-sharing construct) and an overall shorter convalesce period. The rationale for utilizing flexible, straight IMF over other designs is as follows: 1) malreduction risk from too medial entry placement is mitigated by the straight, flexible design, 2) purchase is optimized with screws that directly engage/interlock the nail itself, and 3) neutral syndesmotic slots in the outrigger guide allow for control of syndesmotic re-alignment, and facilitate the “center-center” technique along each ankles individual centroidal axis, rather than an arbitrary 20-30 degree angle from the coronal plane (angulation of other IMF outrigger guides).
The present study has several limitations including the retrospective design, small cohort, and short-term follow-up. Given that the cohort represents the first reported series for the Flexthread IMF nail, intuitively, any learning curve for the system may have affected the early outcomes despite the surgeons extensive IMF nailing experience. The biases may have positively skewed the results, as surgeons with less of an understanding regarding the systems limitations, or less IMF naiing experience in general, may not produce the same outcomes; IMF nailing is technically more challenging than traditional ORIF with plates and screws, and theoretically iatrogenic malreduction/fixation of the syndesmosis could create excessive aberrant force transmission through the construct, potentially resulting in fracture of the flexible IMF. Although the author is aware of a single instance of this occurring for another surgeon, the author has not observed similar breakage in more than 50 Flexthread IMF with syndesmotic realignment along the centroidal axis. Moreover, despite promising emerging data for ankle fractures fixated using IMF nails, no previous study has placed emphasis on syndesmotic realignment along the centroidal axis concurrently with IMF nailing, which the author does anecdotally attribute in-part, to reduced complications, and improved patient outcomes. Therefore, the present findings are considered preliminary, and additional studies with larger cohorts and longer follow-up are warranted to better discern purported advantages presented in the present study.
Conclusion: The present study is the first to report outcomes for the novel, Flexthread IMF nail with concurrent syndesmotic realignment along each patients centroidal axis. Overall, survivorship was 100% at a mean of 6.9 months follow-up, with painless weightbearing, complete radiographic union, and no documented failures, complications, or reoperations related to the IMF nail. The data suggests minimally invasive, arthroscopy assisted, percutaneous IMF nailing with concurrent syndesmotic realignment along the centroidal axis and immediate toe-touch weightbearing is a viable option for most non-neuropathic ankle fractures; irrespective of fracture morphology. Additional studies are warranted to validate the findings.
Informed Patient Consent
Complete informed consent was obtained from the patient for the publication of this study and accompanying images.
Declaration of competing interest
The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References
Tas DB
Smeeing DPJ
Emmink BL
Govaert GAM
Hietbrink F
Leenen LPH
Houwert RM.
Intramedullary Fixation Versus Plate Fixation of Distal Fibular Fractures: A Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies.
Court-Brown CM. A prospective randomised controlled trial of the fibular nail versus standard open reduction and internal fixation for fixation of ankle fractures in elderly patients.
A computed tomography evaluation of two hundred normal ankles, to ascertain what anatomical landmarks to use when compressing or placing an ankle syndesmosis screw.
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