Summary System is intended for internal fixation for combined ankle and subtalar arthrodesis, with design intent to allow independent stabilization of the ankle and subtalar joints Incorporates a staged compression mechanism (StageLock®) enabling controlled, internal, independent compression at the tibiotalar joint (Stage 1) and talocalcaneal joint (Stage 2), with up to 0-5mm of internal compression at each interface Uses a targeting workflow that can include an optional Primary Jig to guide distal-to-proximal starter wire placement and a radiolucent carbon fiber outrigger to support screw targeting and nail rotation checks Indications Indications failed ankle replacement arthritis of ankle and subtalar joint correcting neuromuscular imbalance of hindfoot where bone fusion is required revision of ankle and/or subtalar fusion revision of tibiotalocalcaneal (TTC) fusion talar avascular necrosis (AVN) charcot trauma neuropathy pseudoarthrosis rheumatoid arthritis Contraindications any active infection soft tissue defects, unless concomitant procedures planned foreign body sensitivity to implant materials patients with psychiatric or neurological conditions who are unwilling or incapable of adhering to post-operative care instructions Biological Materials Nail type II anodized titanium alloy Anatomy Osteology tibia intramedullary canal size and tibial metaphyseal flare influence nail diameter selection and reaming strategy talus central talar body/neck trajectory is key for distal-to-proximal wire path and for talar screw purchase limited talar bone stock shifts strategy toward earlier talar screw targeting (optional pathway) calcaneus plantar entry corridor requires centered tuberosity starting point and awareness of plantar cortex when choosing nail depth and distal screw targets hindfoot alignment reduce and align the hindfoot directly beneath the tibia position the foot so it would rest flat on the ground across all planes set neutral or slight external rotation referencing the tibial tuberosity Muscles achilles–gastrocsoleus equinus management may be required to obtain plantigrade alignment and avoid excessive distal plantar translation during reduction peroneals relevant for lateral exposure and subtalar access; may require protection/retraction depending on incision placement tibialis posterior/anterior deformity drivers in varus/valgus and midfoot compensation; balance considerations after TTC fusion EHL anterior approach is centered over EHL, which is retracted laterally Ligaments lateral hindfoot/ankle ligaments lateral approach includes transection of distal ligaments during fibular mobilization/removal capsuloligamentous restraints release/resection tailored to deformity correction and exposure; not specified in provided manufacturer materials Nerves plantar entry nearby neurovascular bundles are at risk during plantar incision and dissection; blunt dissection to plantar calcaneus is recommended to avoid disruption anterior approach superficial peroneal nerve is at risk distally avoid injury during exposure general practice consider medial/lateral plantar nerve/artery course when planning plantar entry and retractors; not specified in provided manufacturer materials Blood supply talus tenuous vascularity and prior trauma/surgery increase AVN and nonunion risk; optimize soft tissue handling and fixation strategy accordingly fusion biology preserve soft tissue envelopes and minimize devascularizing dissection around talus/calcaneus when possible Preoperative Planning Imaging x-ray tibia-fibula films with AP and lateral views used to measure the intramedullary canal and estimate nail diameter evaluate coronal/sagittal alignment goals, bone loss, talar morphology, calcaneal tuberosity trajectory, and prior hardware/stress risers CT helpful for defining talar/calcaneal bone stock, nonunion planes, Charcot fragmentation, and hardware mapping in revision cases Planning considerations plan to bring the hindfoot directly beneath the tibia and achieve a plantigrade foot across planes bone stock limited talar bone stock and an intact distal fibula may drive the talar screw first / anterior approach alternative and additional screw-path checks relative to the fibula nail length plan for the proximal nail end to be at least 50mm past potential stress risers including fractures, non-union sites, bone resection locations, and pre-existing screw holes Surgical Approach Approach selection principles aim to use existing incisions when possible generally, the most effective approach is the one the surgeon is most experienced with Lateral approach incision upper limit at least 2cm above the tibial plafond; continue over the fibula curving anteriorly at the tip of the fibula toward the base of the 4th metatarsal exposure fibula divided proximal to tibial plafond; fibula mobilized with distal ligaments transected; fibula removed to allow access to the subtalar joint graft cancellous bone can be harvested from the resected fibula and utilized as bone graft adjunct separate anteromedial approach may be required to prepare the medial malleolus Anterior approach incision anterior longitudinal incision approximately 1cm lateral to the tibial crest, centered over the EHL tendon interval retract EHL laterally to allow access; perform capsulotomy to expose the tibiotalar joint including medial and lateral gutters nerve pearl take care distally to avoid injury to the superficial peroneal nerve subtalar exposure separate lateral incision just anterior to the peroneal tendons, beginning at the tip of the fibula and extending approximately 4-5cm Technique Workflow patient positioning and room setup positioning options supine with an ipsilateral bump, lateral decubitus, or prone table and draping use a radiolucent table drape above the knee with visualization of the knee and lower limb to assess lower limb alignment distal limbs should extend just over the operating room table fluoroscopy use a large C-arm with entry over the operative site from the contralateral side fusion site preparation ankle joint prepare thoroughly using osteotomes, chisels, burrs, and drill bits fluoroscopy guidance can be helpful a separate anteromedial incision over the medial gutter often helps preserve the medial malleolus as a medial buttress subtalar joint prepare anterior, middle, and posterior facets difficulty reducing the subtalar joint may indicate inadequate resection of the anterior or middle facet or the posteromedial corner of the posterior facet alignment and rotation reduce and align the hindfoot directly beneath the tibia position the foot so it would rest flat on the ground across all planes position the foot in neutral or slight external rotation referencing the tibial tuberosity at the knee tip avoid excessive bone resection which may result in limb shortening or inadequate talar fixation starter wire placement primary jig technique setup position the proximal end of the Primary Jig central to the talar head (critical for accurate wire alignment through the tibial canal); position the distal end approximately 2cm plantar to the fat pad of the heel plantar entry make a plantar incision just distal to the plantar fat pad, slightly lateral to midline perform blunt dissection down to the plantar calcaneus to avoid disruption of nearby neurovascular bundles place the tip of the 3.2mm Starter Wire against the plantar aspect of the calcaneus fluoroscopy use AP, lateral, and calcaneal axial views throughout a lateral view may be used to confirm correct distal-to-proximal trajectory keep the wire centered within the calcaneus, talus, and tibia, terminating in the tibial medullary canal note: when utilizing the anterior approach, position the Primary Jig medial to the first metatarsal to minimize displacement caused by soft tissue interference freehand alternative plantar entry and trajectory use the same plantar incision location and blunt dissection guidance confirm starting point on lateral fluoroscopy advance the 3.2mm Starter Wire through calcaneus, talus, and into tibia using AP, lateral, and calcaneal axial views, keeping the wire centered and terminating in the tibial medullary canal entry reaming exposure extend the plantar incision as needed so it measures 3-4cm perform blunt dissection to the plantar surface of the calcaneus as needed primary reaming insert the 8.0mm Primary Reamer over the 3.2mm Starter Wire and advance proximally through the sole, reaming through subtalar and tibiotalar surfaces into the tibia drill past the metaphyseal flare of the tibia secondary reaming insert the 13.5mm Secondary Reamer over the Starter Wire and ream proximally until the laser mark on the Secondary Reamer is subflush with the plantar cortex of the calcaneus fluoroscopy check check lateral fluoroscopy to ensure the 13.5mm diameter contacts the metaphyseal bone of the tibia and that the proximal portion of the reamer matches the intended countersink of the nail entry reaming and modular/flexible reaming exchange to olive rod after primary and secondary reaming, insert the Exchange Tube over the Starter Wire from the plantar aspect, replace the Starter Wire with the Olive Reaming Rod and advance into the distal tibia confirm position and length under fluoroscopy modular reaming sequence assemble a reamer construct (reamer head + shaft) begin with the smallest diameter reamer head (10.0mm) increase in 0.5mm increments until the desired diameter is achieved under continuous fluoroscopic confirmation final ream guidance oversize the final reamer diameter by 1.0mm relative to the chosen nail diameter reaming technique pearl ensure forward gear is selected for all reaming operations, even when withdrawing the reamer rod management the olive tipped reaming rod can remain in place after modular reaming because the nail can be inserted over it instrumentation setup and checks outrigger assembly insert slotted stage into the outrigger, align arrow with a groove, and rotate the wheel until fully seated thread the external compressor onto the slotted stage tip: do not over-tighten align the notch on the chosen nail to the notch on the outrigger stage engage the nail draw bolt using the draw bolt socket adapter and ratcheting handle and tighten clockwise until the nail is secure precaution: insufficiently tightened components may result in misalignments tip: handle the nail draw bolt with care to prevent dropping outrigger alignment check place guide tube + 5mm drill guide construct into the proximal dynamic or static holes (medial/lateral) for the chosen nail and verify both 4/5mm drills (short for the most proximal hole, long for the next) pass smoothly through the corresponding nail holes rotate the outrigger arm posteriorly and verify the P/A drill guide construct in the “PA 30 DEG” hole allows the P/A step drill to pass smoothly outrigger rotation use the wheel at the bottom of the outrigger to move the arm around the axis of the nail; lock once desired M/L or P/A trajectory is achieved; use “PA 30” as a neutral reference the arrow indicates nail orientation and flips reference when rotating medially vs laterally gold clip removal remove the gold clip prior to insertion by squeezing both sides to disengage it from the nail body discard appropriately the gold clip is designed to secure the internal compression cradle used in Stage 1 and prevent migration during transit nail selection and insertion insertion prerequisites ensure the Exchange Tube has been removed from the tibial canal before inserting the nail insertion over rod insert the nail with attached outrigger into the reamed canal over the olive tipped reaming rod, advancing manually with gentle rotational movements and forward pressure impaction if needed, slide the impactor over the reaming rod onto the base of the outrigger assembly and apply gentle mallet blows to the impactor the carbon fiber outrigger arm, locking wheel, and nail draw bolt should never be hammered vigorous hammering should always be avoided depth target insert the nail so its end is recessed between 5mm and 10mm within the calcaneus precaution the gold clip must be removed prior to nail insertion mallet precaution if a mallet is used, insert the draw bolt adapter and ensure no loosening occurs between the draw bolt and the nail screw insertion sequence reaming rod removal once the nail has been fully inserted, remove the olive tipped reaming rod from the nail before drilling for the first screw nail rotation check with the outrigger posterior, insert the P/A drill guide construct into “PA 30 DEG” and confirm the guide is centered on the calcaneal tuberosity and aligned with the talar neck on lateral view, with trajectory toward the center of the talar neck on lateral and axial views nail rotation is vital to ensure quality talus purchase for the P/A screw proximal tibial screws rotate the outrigger to the medial position for the operative side (R/L) and confirm static vs dynamic configuration drill bicortically medial-to-lateral using the 4/5mm short drill for the most proximal screw and the 4/5mm long drill for the next measure depth using the drill or solid depth gauge insert 5mm screws via guide tube until the driver laser mark meets the end of the guide tube or the screw head is snug against the tibia verify under fluoroscopy precaution: confirm the reaming rod is removed from the nail before drilling to prevent clashes StageLock® compression options option 1 full internal compression description and range independently controlled internal compression (0-5mm) at the tibiotalar joint (Stage 1) by mechanically advancing the talar M/L screw toward the tibia using a threaded cradle internal compression (0-5mm) at the subtalar joint (Stage 2) by advancing the calcaneal M/L screw toward the talus and securing with a secondary screw placed proximally stage 1 steps rotate outrigger lateral place the dynamic talus 5mm screw through the “TIB/TAL COMP” hole apply compression using the Stage 1 driver at the nail base to mechanically compress talus to tibia (up to 5mm) and remove the Stage 1 driver once adequate compression is attained stage 2 steps keep outrigger lateral place the dynamic calcaneus 5mm screw through “CAL/TAL COMP” insert the Stage 2 driver and rotate clockwise to mechanically compress calcaneus to talus (up to 5mm) do not remove the Stage 2 driver until the next step is completed locking step place the locking calcaneus 5mm screw through “CAL/TAL LOCK” (drill lateral-to-medial, measure, insert) once satisfied with subtalar compression, remove the Stage 2 driver from the base of the nail option 2 hybrid internal compression description and range internal Stage 1 compression (0-5mm) at the tibiotalar joint followed by external compression (0-18mm) to the subtalar joint stage 1 steps perform dynamic talus screw placement through “TIB/TAL COMP” and apply Stage 1 internal compression using the Stage 1 driver (up to 5mm) external compression rotate the external compressor clockwise until compression at the tibiotalar and subtalar joints occurs locking step place the locking calcaneus 5mm screw through “CAL/TAL LOCK” while maintaining compression (drill lateral-to-medial, measure, insert) option 3 full external or no compression description and range allows either full external compression (0-18mm) across both joints stabilized with L/M screws in the talus and calcaneus, or no compression at all using the same screw configuration external compression (if used) rotate the external compressor clockwise until compression at the tibiotalar and subtalar joints occur talus screws place talus 5mm screws through “TIB/TAL COMP” (drill lateral-to-medial, measure, insert) and repeat to place the second 5mm screw calcaneus locking screw step manufacturer “locking calcaneus screw insertion” step text specifies drilling using the 4/5mm drill (long or short) in the talus not specified in provided manufacturer materials whether this is intended to be calcaneus for this step compression precaution manual application is recommended over power tools when applying internal compression to prevent potential damage or loss of control P/A screw insertion setup: rotate outrigger posterior; align drill guide construct in “PA 30 DEG” drilling and insertion: drill bicortically posterior-to-anterior using the P/A step drill from the calcaneus to the talus; measure depth; insert the 6mm screw via guide tube until the driver laser mark meets the end of the guide tube or the screw head is snug against the calcaneus end cap insertion and purpose insert an end cap after P/A screw placement and outrigger removal inhibits fibrous and bony ingrowth into the nail which can make removal difficult; adds stability to the internal compression mechanism at Stage 2 attach end cap to the self retaining driver, insert into the distal end of the nail, and secure by rotating clockwise if an end cap is not used, bony ingrowth may occur, potentially increasing difficulty of removal implant removal overview remove the end cap, the 5mm screws, and the 6mm P/A screw attach the extraction adaptor to the distal end of the nail by threading with the larger “top hat,” then tighten by turning the smaller “top hat” thread slap hammer into the extraction adaptor and gently withdraw the nail Optional pathway talar screw first / anterior approach alternative technique rationale the first interlocking screw determines final orientation of the nail within the ankle with severe talar compromise and limited bone stock targeting this screw site first may be advantageous particularly beneficial with an anterior exposure to help avoid interference with the fibula during talar screw insertion wire/jig positioning position the Primary Jig centrally within the talar head using an anterior approach medial to the first metatarsal position the distal end approximately 2cm plantar to the heel fat pad perform plantar incision just distal to the plantar fat pad slightly lateral to midline with blunt dissection to plantar calcaneus confirm trajectory on lateral fluoroscopy and advance the 3.2mm starter wire under AP, lateral, and calcaneal axial views planning checks confirm fluoroscopically that the planned talar screw path avoids the fibula while achieving adequate talus fixation (guide tube may help analyze planned screw path) ensure nail depth/position allows calcaneal screw holes to engage solid cancellous bone without breaching the plantar cortex of the subtalar joint execution proceed with entry/modular reaming and nail insertion per standard workflow then place the talus screw first through “TIB/TAL COMP” in some cases remove small portions of distal fibula to allow optimal positioning and unobstructed access to the talus then proceed with proximal tibial screws and compression steps per selected option Technical specifications Nail constructed from Type II anodized titanium alloy diameters 10.0mm, 11.0mm, 12.0mm available lengths 190mm, 220mm, 250mm base/distal diameter distal diameter of each nail is 12.5mm only the proximal diameter of the nail is changing Instrumentation primary jig optional instrument to guide initial placement of the 3.2mm starter wire distal-to-proximal designed to reduce the number of starter wire attempts includes an alignment “fork” that stabilizes wire alignment and is visible under fluoroscopy carbon fiber/PEEK polymer composite material outrigger carbon fiber outrigger jig is radiolucent and allows rotation of the radial arm through medial, posterior, and lateral positions includes a locking wheel to rotate around the nail axis and then lock physical outrigger is not color-coded impactor deflects the olive reaming rod during nail insertion to allow axial force to be applied with a mallet without contacting the rod Screws Screw families SUCCESSION® M/L Screw Options Diameter Length 5.0mm 22mm 5.0mm 24mm 5.0mm 26mm 5.0mm 28mm 5.0mm 30mm 5.0mm 32mm 5.0mm 34mm 5.0mm 36mm 5.0mm 38mm 5.0mm 40mm 5.0mm 42mm 5.0mm 44mm 5.0mm 46mm 5.0mm 50mm SUCCESSION® P/A Screw Options Diameter Length 6.0mm 85mm 6.0mm 90mm 6.0mm 95mm 6.0mm 100mm 6.0mm 105mm 6.0mm 110mm Design rationale statements each screw is designed with an optimized core diameter to deliver increased strength in critical load-bearing areas 6mm P/A screws are described as providing rigid fixation in the calcaneus and across the subtalar joint Pearls & Pitfalls Pearls use existing incisions when possible, and default to the approach you are most experienced with preserve the medial malleolus as a medial buttress and consider a separate anteromedial incision over the medial gutter for preparation confirm distal-to-proximal starter wire trajectory on lateral fluoroscopy and maintain centering on AP, lateral, and calcaneal axial views through calcaneus, talus, and tibia during 13.5mm secondary reaming, confirm on lateral fluoroscopy that the reamer contacts tibial metaphyseal bone and matches intended nail countersink oversize the final modular reamer diameter by 1.0mm relative to the chosen nail diameter, and consider selecting a nail 1.0mm less than the diameter reamed to reduce impaction and fracture risk keep the reamer in forward gear for all reaming operations, even when withdrawing remove the gold clip prior to nail insertion recess the nail end 5-10mm within the calcaneus before screw placement remove the olive tipped reaming rod before drilling the first screw, and confirm the reaming rod is removed before proximal tibial drilling to prevent clashes use the short and long 4/5mm drills as intended to improve rotational stability and avoid hand interference use manual, not power, application when applying internal compression at Stage 1 and Stage 2 do not remove the Stage 2 driver until the locking calcaneus screw step is completed and subtalar compression is satisfactory place an end cap after P/A screw placement and outrigger removal to inhibit bony ingrowth and add stability to the Stage 2 mechanism Pitfalls malreduction of the hindfoot (varus/valgus/rotation) from incomplete joint preparation or failure to bring the hindfoot beneath the tibia (pdf + general) excessive bone resection during joint preparation leading to limb shortening or inadequate talar fixation plantar entry without blunt dissection to plantar calcaneus risking injury to nearby neurovascular bundles failure to remove the gold clip prior to nail insertion inadequate reaming prompting vigorous hammering; avoid hammering the carbon fiber outrigger arm, locking wheel, or nail draw bolt, and treat hammering as a reaming problem drilling with the reaming rod still in the nail causing instrument clashes poor nail rotation control leading to suboptimal P/A trajectory and compromised talus purchase for the P/A screw plunging through the far tibial cortex with the tapered drill bit, potentially compromising far cortex purchase disengaging the driver before the screw is fully seated, risking incomplete seating and fixation loss using power tools to apply internal compression, risking loss of control or mechanism damage removing the Stage 2 driver before the locking calcaneus screw step is completed, risking loss of subtalar compression omitting an end cap, allowing bony ingrowth that can increase difficulty of removal insufficient tightening of outrigger components leading to misalignment, or over-tightening the external compressor to the slotted stage talar screw path not evaluated relative to an intact distal fibula in anterior exposure, risking cortical breach while trying to obtain talus fixation