import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **PCL**. Location: Inserts posterior intercondylar roof. Risk: Entry too posterior damages PCL, creates apex anterior deformity. Protection: Entry 1cm ANTERIOR to PCL, confirm with lateral fluoro anterior to Blumensaat's line. **ACL**. Location: Anterolateral intercondylar notch. Risk: Eccentric entry or reaming can damage ACL. Protection: Central coronal plane entry, direct visualization of notch, avoid notch impingement with buried nail tip. **Popliteal Artery**. Location: Posterior to distal femur, tethered at adductor hiatus and popliteal fossa. Risk: Posterior cortex perforation during reaming, retractor placement, or fracture displacement. Protection: Maintain knee flexion 30-40°, ball-tipped guidewire, AP/lateral fluoro monitoring. **Common Peroneal Nerve**. Location: Wraps around fibular neck, vulnerable with lateral approaches/positioning. Risk: Compression from positioning, lateral retractor placement. Protection: Padding around knee, avoid valgus stress on knee, careful lateral screw placement. **Infrapatellar Branch of Saphenous Nerve**. Location: Crosses medially 1-2cm below patella, variable course. Risk: Medial parapatellar approach cuts nerve branches. Protection: Longitudinal incision in line with tibial tuberosity, minimize medial dissection, patient counseled re: infrapatellar numbness. | Feature | Retrograde | Antegrade | |---------|------------|-----------| | **Entry Point** | Intercondylar notch | Piriformis/greater trochanter | | **Position** | Supine, knee flexed 30-40° | Lateral or supine with extension table | | **Best For** | Distal 1/3 fractures | Proximal/middle 1/3 fractures | | **Polytrauma** | Preferred (supine access) | Requires lateral positioning | | **Obesity** | Easier entry | Entry can be very difficult | | **Bilateral Femurs** | Efficient (no repositioning) | Requires repositioning | | **Knee Complications** | Anterior knee pain 20-40% | Minimal | | **Hip Complications** | Minimal | Abductor weakness, heterotopic bone | | **Distal Fragment** | Requires 4-5cm minimum | Not as critical | | **Proximal Locking** | Freehand (harder) | Jig-guided (easier) | | Feature | Static Locking | Dynamic Locking | |---------|----------------|-----------------| | **Definition** | Screws in all holes (proximal + distal) | Oval/slot hole allows sliding | | **Fracture Pattern** | Comminuted, segmental, unstable | Simple transverse/short oblique | | **Purpose** | Maintains length, prevents rotation | Allows fracture compression with loading | | **Weight-Bearing** | Protected until healing | Can advance as tolerated | | **Union Rate** | Same | May be slightly faster | | **Dynamization** | May remove proximal screw at 8-12wks if delayed union | Already dynamic | | **Shortening Risk** | Prevented | Possible if comminution missed | | **Rotation Control** | Excellent | Excellent | | Entry Error | Consequence | Prevention | |-------------|-------------|------------| | **Too Posterior** | PCL injury, nail exits anterior (apex anterior deformity) | Entry anterior to Blumensaat's line on lateral | | **Too Anterior** | Difficulty inserting nail, notch impingement, patellofemoral symptoms | 1cm anterior to PCL only, not further | | **Too Medial** | Lateral condyle abutment, valgus malreduction | Center in notch on AP view | | **Too Lateral** | Medial condyle abutment, varus malreduction | Center in notch on AP view | | **Nail Tip Proud** | Notch impingement, anterior knee pain, ACL irritation | Bury tip flush or 2mm recessed | | **Entry Too Large** | Loss of fixation, condyle fracture risk | Enlarge entry gradually, match nail | **Minimum Requirements for Retrograde Nailing:** - **Length**: At least 4-5cm of distal fragment - **Screws**: Minimum 2 distal locking screws (3 if short fragment) - **Position**: Most distal screw as close to joint as possible - **Angle**: Perpendicular to nail axis **When Fragment Too Short (less than 4cm):** 1. Consider antegrade nailing with long nail 2. Consider distal femur locking plate (LISS) 3. Consider combination: plate + retrograde nail 4. Blade plate or condylar screw for very distal **Extension into Joint:** - Intra-articular extension = relative contraindication - Consider CT to assess extension - May need ORIF of articular before nailing **Floating Knee Classification (Fraser):** - **Type I**: Extra-articular (femur + tibia shaft) - **Type IIa**: Knee joint involved - **Type IIb**: Distant joint involved (hip or ankle) - **Type IIc**: Both knee and distant joint involved **Management Principles:** 1. Retrograde femoral nail preferred (efficient supine) 2. Antegrade tibial nail same sitting 3. Same incision can be extended for both 4. Stabilize more unstable fracture first 5. Consider damage control if unstable patient **Outcomes:** - High complication rate (infection 5-10%, nonunion 10%) - Knee stiffness common (early ROM essential) - Vascular injury check mandatory **Patient Position**: Supine, knee flexed 30-40° over radiolucent triangle/bolster **Surgical Approach**: Infrapatellar approach (medial parapatellar or transpatellar tendon) **Incision**: 3-4cm vertical infrapatellar incision, medial parapatellar or midline transpatellar ### Step 1: Preoperative Planning and Setup Preoperative Planning and Setup: Review AP/lateral XR and CT if available to assess fracture pattern, comminution, canal diameter. Measure contralateral femur for nail length (subtract 2-3cm). Plan nail diameter (ream 1-1.5mm larger). Setup radiolucent table with image intensifier opposite side. Confirm AP and lateral views obtainable BEFORE prep/drape. **Technical Tip**: EXAM KEY: Templating on contralateral side gives accurate nail length. Entry point location is MOST CRITICAL technical point - wrong entry causes malreduction, implant failure, knee pain. CT useful for distal extension fractures. - Inadequate imaging may miss intra-articular extension - Wrong length estimation leads to suboptimal fixation ### Step 2: Patient Positioning Patient Positioning: Supine position. Knee flexed 30-40° over radiolucent bolster/triangle under distal thigh. This allows nail insertion trajectory and opens posterior cortex distally. Hip neutral position. Image intensifier on opposite side of fracture. CONFIRM: AP and lateral femur views including hip and knee achievable. **Technical Tip**: EXAM KEY: 30-40° flexion is optimal - less than 30° makes entry difficult, more than 45° risks posterior cortex breach. Bolster position affects reduction - place at fracture level to assist reduction maneuvers. - Excess flexion greater than 45° risks posterior cortex perforation during nail insertion - Common peroneal nerve at risk with poor padding ### Step 3: Surgical Approach to Knee Surgical Approach to Knee: Midline or medial parapatellar 3-4cm longitudinal incision over inferior pole patella. CHOICE: (1) Transpatellar tendon (longitudinal split in midline) OR (2) Medial parapatellar (retract tendon laterally). Deepen to expose fat pad. Excise triangular portion of fat pad to visualize intercondylar notch entrance. **Technical Tip**: EXAM KEY: Medial parapatellar PRESERVES tendon integrity (preferred by many) but gives slightly off-centre entry. Transpatellar gives central entry but requires meticulous tendon repair. If split tendon, tag with stay sutures for later repair. - Infrapatellar branch of saphenous nerve crosses incision medially - Patellar tendon injury if aggressive retraction ### Step 4: Identify Anatomic Entry Point Identify Anatomic Entry Point: Direct visualization of intercondylar notch. ENTRY POINT: anteroposterior - centre of notch (equal distance from lateral/medial walls), 1cm ANTERIOR to PCL insertion. Lateral view: ANTERIOR to Blumensaat's line (roof of notch). Use awl to mark/create starting point in subchondral bone. **Technical Tip**: EXAM KEY: Entry TOO POSTERIOR damages PCL, nail driven anterior (apex anterior angulation). Entry TOO ANTERIOR creates difficulty insertion, notch impingement, patellofemoral symptoms. Blumensaat's line is KEY lateral landmark. - PCL injury from posterior entry point - ACL injury from eccentric lateral entry ### Step 5: Guidewire Insertion Guidewire Insertion: Insert ball-tipped guidewire through entry point under LIVE fluoroscopy (AP and lateral simultaneously if possible). Direct wire down femoral canal with gentle manipulation. GOAL: central in canal on AP and lateral views, passing fracture site without eccentric positioning. If fracture displaced, may need manipulation or small incision for reduction aids. **Technical Tip**: EXAM KEY: Ball-tip prevents guidewire getting lost in soft tissues. Watch tip CONTINUOUSLY on fluoro - if eccentric, withdraw and redirect. Difficulty passing fracture = need closed reduction maneuvers or limited open reduction. - Guidewire exit through fracture into soft tissues - Wire advancement out through cortex proximally ### Step 6: Fracture Reduction (if needed) Fracture Reduction (if needed): Assess reduction on AP/lateral. ACCEPTABLE: less than 5° angulation, less than 1cm shortening, rotation matched to contralateral. If unacceptable: (1) Closed manipulation with traction/rotation, (2) Percutaneous clamps, (3) Mini-open at fracture site. Provisional reduction with K-wires or clamps. THEN pass guidewire. **Technical Tip**: EXAM KEY: Reduction BEFORE reaming is critical - reaming displaced fracture risks eccentric canal, cortical perforation, malreduction. Rotation assessed by comparing lesser trochanter profile to contralateral femur on AP view. - Malreduction accepted and locked in with nail - Rotational malreduction hardest to assess ### Step 7: Opening the Medullary Canal Opening the Medullary Canal: Over guidewire, use cannulated awl or entry reamer to open distal femur entry portal. Start small, enlarge gradually. FEEL: penetration through subchondral bone into medullary canal. Confirm position with fluoro - should be INTRAMEDULLARY, not in soft tissue or articular. **Technical Tip**: EXAM KEY: Gentle controlled force - excessive force risks fracture displacement, condyle fracture, or guidewire advancement. Opening adequately prevents difficulty with reamer passage. - Iatrogenic condyle fracture with excessive force - Entry through articular surface ### Step 8: Sequential Reaming Sequential Reaming: Ream over BALL-TIPPED guidewire in 0.5-1mm increments starting 1-1.5mm smaller than anticipated nail size. Ream to measured diameter (templated) plus 1-1.5mm. Feel for chatter (cortical contact), watch fluoro for eccentric reaming. GOAL: uniform reaming without eccentricity or fracture displacement. **Technical Tip**: EXAM KEY: Ball-tipped wire essential - prevents wire advancement or exit through fracture. Reamings have osteogenic potential. Ream 1-1.5mm LARGER than nail for ease of passage. Stop if excessive resistance (risk perforation). - Posterior cortex perforation (popliteal artery injury) - Eccentric reaming causing malreduction ### Step 9: Nail Insertion Nail Insertion: Attach selected nail (length from template, diameter 1-1.5mm smaller than final reaming) to jig. Insert over guidewire with gentle rotatory movements. Monitor passage on fluoro - should remain central, pass fracture smoothly. If resistance: stop, assess with fluoro, may need additional reaming or wire repositioning. Advance until nail tip 5-10mm ABOVE lesser trochanter. **Technical Tip**: EXAM KEY: Nail length critical - TOO SHORT: inadequate proximal fixation, TOO LONG: greater trochanter pain, difficulty with proximal locking. Tip position 5-10mm ABOVE lesser trochanter optimal. Rotatory insertion prevents incarceration. - Nail too long causes trochanteric pain - Nail too short gives inadequate proximal purchase ### Step 10: Confirm Reduction and Nail Position Confirm Reduction and Nail Position: Full AP and lateral fluoroscopy: (1) Fracture reduction acceptable, (2) Nail central in medullary canal throughout, (3) No cortical perforation, (4) Distal nail position in notch acceptable, (5) Proximal nail tip position appropriate. Address any issues NOW before locking. **Technical Tip**: EXAM KEY: Final reduction check BEFORE locking - once locked, difficult to adjust. Varus/valgus malreduction common - check mechanical axis on AP. Flexion/extension malreduction - check lateral. Rotation hardest to assess - compare to contralateral. - Locking malreduced fracture - Missing rotational deformity ### Step 11: Distal Locking (Static) Distal Locking (Static): Using jig-guidance (attached to nail), insert 2-3 distal interlocking screws. TECHNIQUE: stab incision, tissue protector, drill through near cortex-nail-far cortex, measure, insert screw 5mm longer than measurement. Bicortical purchase essential. Most distal screw as close to joint as possible (maximum fragment control). **Technical Tip**: EXAM KEY: DISTAL LOCKING FIRST for retrograde nails (opposite of antegrade). Jig-guided distal locking very accurate. Ensure screws don't penetrate joint - confirm with fluoro. Minimum TWO screws, THREE if short distal fragment. Locking provides rotational/length control. - Intra-articular screw penetration - Missing nail hole (bent jig) ### Step 12: Proximal Locking (Static or Dynamic) Proximal Locking (Static or Dynamic): FREEHAND technique (jig doesn't reach proximal femur): (1) Perfect circles technique - rotate C-arm until screw hole appears as PERFECT CIRCLE, (2) Stab incision centered on circle, (3) Drill centered in circle on both orthogonal views, (4) Measure and insert screw. Insert 1-2 proximal screws. STATIC (no sliding) for comminuted/unstable fractures, DYNAMIC (allow sliding) for simple transverse fractures. **Technical Tip**: EXAM KEY: Freehand locking technically demanding - requires perfect circle technique mastery. Radiation exposure higher (protect thyroid, eyes). STATIC vs DYNAMIC: simple fractures can be dynamic (allows compression), comminuted MUST be static (prevent shortening). - Missed nail hole (eccentric drilling) - Excessive radiation exposure to surgeon ### Step 13: Final Imaging and Assessment Final Imaging and Assessment: Complete AP/lateral fluoroscopy: (1) ALL screws fully inserted, bicortical, correct length, (2) Reduction maintained (alignment, length, rotation), (3) No intra-articular screw penetration (distal screws, change knee flexion/rotation during check), (4) No hardware complications visible. Document images. **Technical Tip**: EXAM KEY: INTRA-ARTICULAR SCREW penetration most common error - MUST check with knee in flexion/extension and rotation (changes condyle profile). Screw length: aim 5mm past far cortex. If unicortical purchase only = inadequate. - Missing intra-articular hardware - Accepting suboptimal reduction ### Step 14: Wound Closure Wound Closure: If tendon split: repair with #2 non-absorbable suture (Krackow or similar locking technique), ensure solid repair to prevent rupture. Irrigate thoroughly. Close retinaculum, subcutaneous with absorbable suture, skin. Bulky compressive dressing. NO DRAIN typically needed. **Technical Tip**: EXAM KEY: Patellar tendon repair CRITICAL if split approach used - rupture is devastating complication. Krackow suture technique gives strongest repair. Early protected ROM improves outcomes if fixation stable. - Inadequate patellar tendon repair - Missed injury requiring documentation ### Step 15: Postoperative Protocol Postoperative Protocol: Weight-bearing status depends on fracture pattern and fixation stability. STABLE simple fracture with good fixation: early protected weight-bearing (TDWB advancing to PWB then FWB over 6-12 weeks as clinical/radiographic healing progresses). UNSTABLE comminuted fracture: NWB 6-8 weeks minimum. Early ROM exercises (prevent stiffness). DVT prophylaxis per protocol. Serial XR at 2, 6, 12 weeks. **Technical Tip**: EXAM KEY: Retrograde nails allow EARLIER mobilization than plates (load-sharing vs load-bearing). Knee stiffness is common complication - early ROM critical. Full weight-bearing when radiographic/clinical healing (typically 8-12 weeks simple, 12-16 weeks comminuted). - Early weight-bearing on unstable fixation - Knee stiffness from immobilization Weight-bearing: STABLE simple fractures - touch-down weight-bearing advancing to partial then full over 6-12 weeks as clinical/radiographic healing progresses. UNSTABLE comminuted fractures - non-weight bearing 6-8 weeks minimum. ROM: immediate knee ROM exercises to prevent stiffness - flexion/extension in brace if needed initially. DVT prophylaxis per protocol (LMWH or DOACs). Follow-up: 2, 6, 12 weeks with AP/lateral XR to assess union, alignment, hardware position. Union expected 8-12 weeks simple fractures, 12-16 weeks comminuted. Full activity when clinical/radiographic union confirmed, typically 3-6 months. 1. Ricci WM, Bellabarba C, Evanoff B, et al. Retrograde versus antegrade nailing of femoral shaft fractures. J Orthop Trauma. 2001;15(3):161-169. 2. Tornetta P 3rd, Tiburzi D. Antegrade or retrograde reamed femoral nailing: a prospective, randomised trial. J Bone Joint Surg Br. 2000;82(5):652-654. 3. Herrera-Soto JA, Price CT. Retrograde intramedullary nailing of the femur. J Am Acad Orthop Surg. 2009;17(11):687-696. 4. Papadokostakis G, Papakostidis C, Dimitriou R, Giannoudis PV. The role and efficacy of retrograding nailing for the treatment of diaphyseal and distal femoral fractures: a systematic review of the literature. Injury. 2005;36(7):813-822. 5. Ostrum RF, Agarwal A, Lakatos R, Poka A. Prospective comparison of retrograde and antegrade femoral intramedullary nailing. J Orthop Trauma. 2000;14(7):496-501. 6. Moed BR, Watson JT. Retrograde nailing of the femoral shaft. J Am Acad Orthop Surg. 1999;7(4):209-216. 7. Bong MR, Kummer FJ, Koval KJ, Egol KA. Intramedullary nailing of the lower extremity: biomechanics and biology. J Am Acad Orthop Surg. 2007;15(2):97-106. 8. Canadian Orthopaedic Trauma Society. Reamed versus unreamed intramedullary nailing of the femur: comparison of the rate of ARDS in multiple injured patients. J Orthop Trauma. 2006;20(6):384-387. 9. Lepore S, Capuano N, Romano G. Retrograde nailing of femoral shaft fractures in patients with hip arthroplasty. Arch Orthop Trauma Surg. 1999;119(5-6):286-289. 10. Handolin L, Pajarinen J, Lindahl J, Hirvensalo E. Retrograde intramedullary nailing in distal femoral fractures--results in a series of 46 consecutive operations. Injury. 2004;35(5):517-522.

Retrograde Femoral Nailing

Retrograde Femoral Nailing