Isolated Foot Delta Frame Construct for External Fixation of Midfoot and Rearfoot Fracture-Dislocation Injuries Troy Boffeli DPM, FACFAS; Mark Goss, DPM Regions Hospital / HealthPartners Institute for Education and Research - Saint Paul, MN

Statement of Purpose Case Study Figure 2. Clinical photos of crush injury upon presentation to ED Figure 7. Medial delta frame application pearls

External fixation is commonly used in the acute management of Patient Presentation a b Initial presentation following crush orthopedic trauma involving gross instability, comminution, open fracture, A 36 year old female without tobacco use or significant past medical injury with open fractures and and severe soft tissue injury. Various external fixation constructs are history presented to the emergency department (ED) approximately 30 medial soft tissue degloving injury. (a) The entire plantar soft tissue described in the literature for complex foot injuries. However, descriptions minutes after sustaining a work-related left foot crush injury involving a fork envelope was torn from the of isolated foot constructs is limited. External fixation for rearfoot and ankle lift. Physical exam demonstrated gross deformity with extensive laceration at osseous attachments including the trauma primarily involves delta frame constructs that span the ankle joint the medial aspect of the foot, extending from the heel to the midfoot (Figure calcaneus. (b) Note compromised with mid-tibial half pins. Mini-rail systems are designed for use in midfoot 2). This involved a full-thickness degloving injury and open fractures of the 1st soft tissue across the dorsum of and forefoot trauma to maintain length along the medial and lateral metatarsal and calcaneus with Lisfranc dislocation. No grossly appreciable the foot. Schanz pins are placed in the first metatarsal shaft, talar neck, and calcaneal tuberosity for medial column delta frame application. Safe zones for pin placement are confirmed by palpation and with fluoroscopy. columns, but comminuted fractures and complex dislocation injuries vascular or neurologic compromise was identified on exam. Plain film X-ray Figure 3. Initial imaging of left foot crush injury frequently require multi-planar stabilization. This case study describes our and CT examination of the left foot demonstrated comminuted fractures of Analysis and Discussion preferred isolated foot delta frame construct. We address indications, the calcaneus, cuboid, first metatarsal, and second metatarsal (Figure 3). surgical technique, staging protocol, and advantages over traditional Extreme plantar angulation of the first metatarsal was identified with tenting The isolated foot delta frame construct provides distraction to maintain medial or methods. of the overlying dorsal skin. There was also dislocation of the calcaneocuboid lateral column length, stable multiplanar deformity correction, and spanning of soft joint with lateral column shortening through the fractured cuboid. No osseous tissue deficits. Monorail-type fixators commonly used in the foot impart limited sagittal Literature Review injury was identified at the talus, tibia, or fibula. No additional injuries were plane stability. Improved stability can be achieved with additional proximal and distal pins however this may not be feasible due to the proximity of neurovascular structures Modern external fixation designs are believed to have originated in the identified. Tetanus prophylaxis and IV antibiotics were administered. in the midfoot and rearfoot, and limited non-articular surface area on the talus. mid-19th century and wide acceptance of the technique began in the mid- Imaging demonstrates comminuted Osseous trauma necessitating definitive management with ORIF typically requires a 20th century (1,2). External fixation technique has evolved with Procedure Selection Criteria fractures through the midfoot and rearfoot. Note comminuted calcaneus staged approach following delta frame application in the setting of open fracture, or advancements in technology but the demonstrated benefits and basic We commonly use the isolated foot delta frame construct for initial and cuboid fractures with severely soft tissue compromise from high-energy, crush or degloving injuries. ORIF is performed principles remain (1,2). reduction and stabilization of unstable or comminuted fracture-dislocation maligned first metatarsal base fracture on a delayed basis following adequate recovery of soft tissues, epithelialization of Compared to internal plate and screw fixation in the setting of acute injuries involving the Lisfranc or Chopart joint, and cuneiform, navicular, or with Lisfranc injury. Fixation options were fracture blisters if present, and reduction of infection risk in the setting of open fracture. trauma, external fixation is less traumatic to local soft tissues and minimizes cuboid. These injuries can result in medial and lateral column shortening that limited by the severe soft tissue injury. Figure 7 demonstrates our typical isolated medial foot delta frame construct. The further disruption to potentially tenuous osseous perfusion (3). By require length restoration. This frame construct is particularly useful when Figure 4. Stage I treatment with placement of external fixation proximal bar stabilizes the talus and calcaneus and anchors the frame proximally preserving ligamentous, capsular, and periosteal tissues, external fixation there is a concomitant degloving or crush injury that potentially compromises without crossing the ankle joint or requiring tibial pin placement, unlike previously also allows reduction by ligamentotaxis with stable fixation and maintained local soft tissue and contraindicates extensive dissection for internal fixation. described delta frame constructs or circular frames. The dorsal bar maintains medial length for comminuted and unstable fractures or dislocations (4). External Additionally, external fixation may be used to augment internal fixation that column length with two stable pins and a bar spanning the midfoot. The plantar bar fixation commonly serves as provisional fixation prior to more definitive requires additional stability. This construct preserves ankle joint range of maintains arch integrity and limits sagittal plane motion across comminuted management but can also serve as definitive fixation in select cases. Various motion, and is not appropriate in the setting of fractures involving the talus, injuries. This frame construct also spans midfoot soft tissue injuries and can be applied constructs have been described for use in acute foot and ankle trauma, with ankle, or distal tibia. laterally depending on fracture location and soft tissue compromise. As with application application in the forefoot, midfoot, rearfoot, and ankle (1). Frame design of any external fixation construct, pin placement should avoid iatrogenic damage to generally involves percutaneously placed half-pins or wires, externally Stage I Surgical Technique b neurovascular structures, tendons, and ligaments. Cadaveric study has demonstrated connected by circular frames, bars and rods, and monobody-type devices. Emergency surgery was performed on the date of injury under general that when placed within 2 cm of the first tarsometarsal joint, transverse pin placement Safe placement of half-pins and wires requires knowledge of well- anesthesia. No tourniquet was utilized. The operation involved thorough through the first metatarsal and into the first intermetatarsal space consistently documented safe zones to avoid neurovascular compromise (5-7). inspection, irrigation, excision of non-viable tissue, reduction and increases risk of damage to the deep plantar branch of the dorsalis pedis artery (7). The Planar stability is largely determined by the fixation construct. Stability is percutaneous pin fixation of the calcaneus fracture, primary closure of the first metatarsal pin is typically placed midway between the dorsal and plantar surfaces improved with increased diameter of half-pins, more points of fixation, open wound, insertion of half pins, and reduction / stabilization of the to maximize stability and reduce the risk of fracture. Also, the Shanz pin should be sized decreased frame to bone distance, and placement of pins in different planes midfoot fracture dislocation injuries via frame application (Figure 4a). appropriately to the respective bone. We prefer to use 3.0-4.0 mm pins in metatarsals, (2). Regarding pin-to-bar designs, rigidity is typically imparted by multiple No additional incisions were made as the fractures were partially a c as recommended by Nayagam (5). Safe zones for pin placement in the calcaneus and carbon fiber rods. Pin-to-bar fixation has been described for use across accessible through the degloved plantar tissue. Reduction of the calcaneus Acute treatment involved incision and drainage of the open fractures and primary closure of the medial wound. Percutaneous pins were placed through the plantar heel for initial stabilization of talus have also been described (5-6). The recommended medial calcaneal safe zone is at unstable midfoot and forefoot injuries, with traditional constructs being fracture was performed, which was temporarily fixated with two the calcaneus fracture. Reduction and stabilization of the remaining fracture-dislocation injuries the tuberosity, posterior to the neurovascular bundle and extrinsic tendons. Laterally, primarily monoplanar (Figure 1a) (8-9). More stable constructs have been percutaneously placed 0.062 inch Kirchner wires. Reduction was also was accomplished with medial and lateral isolated foot delta frames. Fracture blister formation, the calcaneal safe zone is posterior to the peroneal tendons and sural nerve. Safe pin described for injuries involving the ankle and calcaneus, with delta frame performed at the intra-articular calcaneocuboid joint fracture-dislocation. An swelling, and intact fixation are demonstrated here at 11 days post injury. placement in the talus is at the neck medially or laterally to avoid damage to articular constructs crossing the tibiotalar joint (Figure 1b) (10-11). Additionally, isolated foot delta frame was applied laterally to maintain lateral column cartilage. A medial talar pin should be superior to the tibialis posterior tendon and distal circular frame constructs have been used for foot and ankle trauma (1). To length. This involved parallel placement of three 4.0 mm Schanz pins in the Figure 5. Stage II surgery three weeks after injury th enough to prevent medial malleolar impingement with ankle joint range of motion. our knowledge, no isolated foot delta frame constructs that spare ankle calcaneal tuberosity, talar neck and 5 metatarsal base, avoiding the Stage II ORIF was performed three weeks post injury to This case involved both medial and lateral delta frame application due the instability joint range of motion have been described for use in acute foot trauma. fractures. Combination clamps were used to connect 4.0 mm carbon fiber allow adequate soft tissue recovery. The bars and clamps rods to the Schanz pins to form the lateral delta frame construct as shown in were removed from the frames and re-sterilized while the and shortening at the medial and lateral columns. However, the isolated foot delta figure 4b. The medial column was reduced and stabilized through a medial half pins were left in place. A dorsal medial column incision frame is more commonly applied medially. This construct is not recommended for Figure 1. External fixation constructs in foot and ankle trauma isolated foot delta frame. 4.0 mm Schanz pins were placed in the talar neck, was used for open treatment of the Lisfranc fracture fractures involving the talus or injuries that would otherwise contraindicate ankle joint calcaneus and first metatarsal head (Figure 4c). dislocation involving spanning plate fixation of the medial range of motion. This preliminary description of the isolated foot delta frame construct column. A percutaneous screw was placed in the is limited, as it is a case study of a single patient. Further evaluation and direct calcaneus. The medial and lateral frames were reassembled comparison to other methods of fixation in similar situations are needed. Postoperative Course and Stage II Fracture Fixation to provide ongoing support for an additional six weeks. Postoperative care involved admission for pain management, strict bed We have found the isolated foot delta frame construct to be useful for initial reduction and stabilization of fracture or dislocation injuries involving the subtalar, rest, and monitoring of tissue swelling. At postoperative day one, the patient Figure 6. Follow up after frame removal and one year later was noted to have asymptomatic and acute blood loss anemia, with Chopart, and Lisfranc joints, and at the cuneiforms, navicular, and cuboid. This construct hemoglobin at 9.8 g/dl. No transfusion was required. Three weeks after the a c (a) Stage III surgery is particularly useful in the setting of potential soft tissue envelope compromise due to involved removal of crush or degloving injuries, as it provides stable, multiplanar fixation with a minimally initial operation, the second stage operation was performed with cannulated medial and lateral invasive approach. Other advantages of this construct include availability of screw fixation of the calcaneus and open reduction with internal fixation delta frames six components for emergency surgery, relatively low cost, and relative technical ease of (ORIF) of the medial column as shown in figure 5. Stage 2 surgery involved weeks post ORIF. reapplication of the medial and lateral delta frame constructs. The frames Lateral radiograph application in the setting of trauma. shown here at eight were left in place for an additional six weeks to support internal fixation and weeks post ORIF. References other injuries. Protected weight bearing in a below-knee fracture boot began b (b-c) Radiographic a b 1. DiDomenico LA, Ziran BH, Cane LZ. The use of external fixation in the lower extremity. In International Advances in Foot and Ankle Surgery, pp 439-452, edited by A Saxena, Springer, London, 2012 approximately four weeks after frame removal followed by gradual evaluation at one 2. Fragomen AT, Rozbruch SR. The mechanics of external fixation. HSS Journal 3:13-29, 2007. The basic isolated foot external Traditional lower extremity delta frame 3. Claes L, Heitemeyer U, Krischak G, Braun H, Hierholzer G. Fixation technique influences osteogenesis of comminuted fractures. Clinical Orthopaedics and Related Research 365:221-229, 1999. year post injury 4. Schepers T, Patka P. Treatment of displaced intra-articular calcaneal fractures by ligamentotaxis: current concepts review. Archives of Orthopaedic and Trauma Surgery 129:1677-1683, 2009. frame construct involves distal and construct is shown here. Half pins in the tibia progression to full ambulation in regular shoes. Imaging at eight weeks 5. Nayagam S. Safe corridors in external fixation: the lower leg (tibia, fibula, hindfoot and forefoot). Strategies in Trauma and Limb Reconstruction 2:105-110, 2007. demonstrates 6. Santi MD, Botte MJ. External fixation of the calcaneus and talus: an anatomical study for safe pin insertion. Journal of Orthopaedic Trauma 10:487-491, 1996. proximal pins connected by a allow distraction and stabilization of following ORIF (Figure 6a) and at twelve months (Figure 6b-c) following the 7. Barrett MO, Wade AM, Della Rocca GJ, Crist BD, Anglen JO. The safety of forefoot metatarsal pins in external fixation of the lower extremity. The Journal of Bone & Joint Surgery 90:560-564, 2008. stable foot 8. Miller JC, Shever S. Use of external fixation and primary wound closure in an open comminuted first metatarsal fracture: a case report. The Journal of Foot and Ankle Surgery 47:46-50, 2008. uniplanar bar that spans the area comminuted fractures of the distal tibia, ankle, 9. Chandran P, Puttaswamaiah R, Dhillon MS, Gill SS. Management of complex open fracture injuries of the midfoot with external fixation. The Journal of Foot and Ankle Surgery 45:308-315, 2006. injury confirmed desired healing progress without mechanical complication, architecture and 10.Sirkin M, Sanders R, DiPasquale T, Herscovici Jr D. A staged protocol for soft tissue management in the treatment of complex pilon fractures. Journal of Orthopaedic Trauma 13:78-84, 1999. of injury. calcaneus, and talus. healed fractures. 11.Kissel CG, Husain ZS, Cottom JM, Scott, RT, Vest J. Early clinical and radiographic outcomes after treatment of displaced intra-articular calcaneal fractures using delta-frame external fixator infection, or instability despite major fracture dislocation injuries. construct. The Journal of Foot and Ankle Surgery 50:135-140, 2011.

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