import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' plantar plate > crossed lag screws (decreasing stability and union rates)" ]} /> **Location**: Crosses dorsal incision 2-3mm from incision line, multiple branches **Protection**: Careful subcutaneous dissection with loupe magnification, identify and retract branches medially, avoid aggressive retraction **Injury rate**: 5-10% - causes dorsal foot numbness and neuroma formation **Location**: Runs between EHL and EHB tendons, 15-20mm LATERAL to standard incision, palpable preoperatively **Protection**: Stay MEDIAL to EHL tendon, palpate pulse before incision, avoid lateral dissection beyond EHL **Injury**: Catastrophic - can cause forefoot ischemia requiring amputation **Location**: Accompanies dorsalis pedis artery laterally between EHL and EHB, 15-20mm from incision **Protection**: Stay medial to EHL, no blind lateral dissection, direct visualization if approaching EHL **Injury**: Causes first web space numbness and EHB/EDL weakness **Location**: 10-15mm plantar to TMT joint, at medial midfoot **Protection**: Do NOT extend dissection plantarly beyond joint line, avoid excessive plantar retraction, no plantar screw penetration **Injury**: Causes medial plantar sensory loss and intrinsic muscle weakness **Location**: Landmark structure - incision must stay MEDIAL to it, crosses TMT joint dorsally **Protection**: Identify early and retract laterally with blunt retractor, avoid sharp dissection near tendon **Injury**: Loss of hallux extension requiring tendon repair or transfer ## Anatomical Considerations ### First TMT Joint Anatomy - **Joint configuration**: First metatarsal base articulates with medial cuneiform - **Shape**: Medial cuneiform is trapezoid - wider DORSALLY (12-15mm) than plantarly (8-10mm) - predisposes to dorsiflexion malposition - **Orientation**: Joint line oriented 45° dorsomedial to plantar lateral - **Stability**: Stabilized by capsule, plantar and dorsal ligaments (Lisfranc ligament attaches C1 to M2 base, not M1) - **Blood supply**: Dorsalis pedis (lateral), medial plantar artery (plantar), periosteal vessels ### Surface Anatomy & Approach - **Palpable landmarks**: Navicular tuberosity 3cm proximal, 1st metatarsal base 3-4cm distal to navicular - **EHL tendon**: Critical landmark - stays LATERAL to it for safety - **Dorsalis pedis**: Palpable between EHL and EHB, 15-20mm lateral to incision line - **Incision position**: Dorsomedial 4-5cm longitudinal centered over TMT joint ### Biomechanical Pathology - **Hypermobility**: Normal TMT translation <5mm; pathologic >9mm dorsoplantar translation - **Deformity mechanism**: Hypermobile TMT allows 1st metatarsal to drift into varus (increased IMA), hallux compensates into valgus - **Force transmission**: 50% body weight through 1st ray during push-off - hypermobility allows progressive deformity - **Recurrence mechanism**: Distal procedures in hypermobile patients fail because apex of deformity (TMT) remains mobile ## Indications ### Primary Indications 1. **Severe hallux valgus with hypermobility** - IMA >18-20° (severe intermetatarsal angle) - HVA >40° (hallux valgus angle) - TMT hypermobility >9mm dorsoplantar translation 2. **Metatarsus primus varus** - Structural varus of 1st metatarsal - Fixed deformity at TMT level 3. **Revision bunion surgery** - Failed chevron, scarf, or other distal procedures - Recurrent deformity due to unaddressed TMT instability 4. **Younger active patients** - Age <50 years requiring definitive correction - High activity demands precluding nonunion risk of osteotomy 5. **Degenerative TMT arthritis with hallux valgus** - Concurrent arthritis and deformity - corrects both ### Relative Indications - Moderate hallux valgus (IMA 15-18°) with clear hypermobility - Rheumatoid arthritis affecting first ray - Neuromuscular deformity with dynamic component ### Contraindications **Absolute**: - Active infection at surgical site - Severe peripheral vascular disease (non-palpable pedal pulses, ABI <0.5) - Charcot neuropathy with active inflammation - Non-ambulatory patient **Relative**: - Heavy smoker (>1 pack/day) - nonunion risk 20-30% - Uncontrolled diabetes (HbA1c >8%) - infection and nonunion risk - Severe osteoporosis - fixation failure risk - Spastic neuromuscular disorder - deforming forces persist - Mild deformity (IMA <15°) - distal procedures preferable ## Clinical Assessment ### History - **Deformity progression**: Rate of worsening, prior failed procedures - **Shoe wear**: Wide toe box, difficulty with shoe fit - **Pain location**: MTP joint medially, lesser metatarsals (transfer), TMT midfoot - **Functional limitation**: Walking distance, footwear restrictions - **Medical optimization**: Smoking cessation, diabetic control, vascular status ### Physical Examination 1. **Deformity assessment** - HVA measurement clinically (angle between hallux and 1st metatarsal) - IMA assessment (medial prominence, widened forefoot) - Lesser toe deformities (crossover 2nd toe, hammer toes from transferred load) 2. **TMT hypermobility testing** - CRITICAL for surgical decision - Stabilize hindfoot and midfoot with one hand - Grasp 1st metatarsal head with other hand - Dorsally and plantarly translate - Measure displacement: <5mm normal, 5-9mm borderline, >9mm pathologic - Compare with contralateral side 3. **MTP joint assessment** - ROM: normal 65-75° dorsiflexion, 15° plantarflexion - Sesamoid position: subluxation indicates severe deformity - Hallux pronation (rotation into valgus) 4. **Vascular examination** - Palpate dorsalis pedis and posterior tibial pulses - Capillary refill <2 seconds - Ankle-brachial index if any concern 5. **Neurology** - Sensation intact (diabetic neuropathy assessment) - Motor function (EHL, FHL strength) ### Imaging **Weight-bearing AP foot radiograph** - MANDATORY - Measure IMA (intermetatarsal angle): Normal <9°, mild 9-13°, moderate 13-18°, severe >18° - Measure HVA (hallux valgus angle): Normal <15°, mild 15-30°, moderate 30-40°, severe >40° - Assess TMT joint: arthritis, subluxation - Assess sesamoid position (subluxation indicates soft tissue imbalance) - Distal metatarsal articular angle (DMAA): >10° suggests intra-articular deformity **Weight-bearing lateral foot radiograph** - 1st metatarsal declination angle: normal 15-25° below horizontal - Check for TMT arthritis - Assess medial arch **Stress radiographs** (optional) - Lateral stress view with dorsal force on 1st metatarsal - Demonstrates >9mm translation = hypermobility **Advanced imaging** (selective) - **MRI**: Not routine, consider if concern for AVN, occult fracture, soft tissue pathology - **CT**: For revision cases with complex anatomy or to assess TMT arthritis severity ## Surgical Planning ### Correction goals - IMA: Correct to <10° (aim 5-8°) - HVA: Correct to <15° - Sesamoid reduction: Subluxation corrected - Sagittal alignment: NEUTRAL or slight plantarflexion (avoid dorsiflexion) - Length: Minimize shortening (<5mm) to prevent transfer metatarsalgia ### Fixation planning - **Preferred**: Dorsomedial locking plate (low-profile, anatomic) + lag screw - **Alternative**: Plantar plate (biomechanically superior but technically demanding) - **Avoid**: Crossed lag screws alone (higher nonunion 12-15%) ### Adjunct procedures consideration - **Akin osteotomy**: If residual hallux valgus interphalangeus (DMAA >10°) - **Medial eminence**: Resection usually not needed if deformity fully corrected - **Lateral soft tissue release**: Usually not needed with Lapidus (correction at TMT eliminates tension) ### Patient consent - key points - **Union time**: 10-12 weeks until full consolidation - **Nonunion risk**: 5-8% with plate, higher in smokers - **NWB period**: 6 weeks strict non-weight bearing, then gradual progression - **Transfer metatarsalgia**: 10-15% if excessive shortening or dorsiflexion - **Hallux varus**: 2-5% if overcorrection - **Nerve injury**: 5-10% superficial sensory (dorsomedial cutaneous) - **Hardware removal**: 10-15% require removal for prominence - **Return to activities**: 4-6 months for full unrestricted activities ## Positioning and Preparation **Patient Position**: Supine with small bump under ipsilateral hip for 15-20° external rotation. Foot at end of table for intraoperative imaging access. Radiolucent table and triangle positioning aid optional. **Anesthesia**: General or regional (ankle block). Popliteal block provides excellent postoperative analgesia. **Tourniquet**: Ankle tourniquet (250mmHg) or thigh tourniquet (300mmHg based on limb circumference formula). Exsanguinate with Esmarch or elevation. **Preparation**: Prep circumferentially to mid-calf. Drape to allow full foot exposure and fluoroscopy access. **Equipment Check**: - Fluoroscopy (AP, lateral, oblique views) - Dorsomedial locking plate system (TMT-specific, low-profile) - 3.5mm or 4.0mm lag screw instrumentation - Sagittal saw with narrow blade - Smooth K-wires for provisional fixation - Small bone curettes and rongeurs ## Surgical Technique ### Step 1: Incision and Superficial Dissection **Incision**: Dorsomedial longitudinal incision 4-5cm centered over 1st TMT joint. Start 2cm proximal to joint, extend 2-3cm distal. Stay centered over metatarsal shaft medially. **Subcutaneous dissection**: Carefully incise subcutaneous tissue. **CRITICAL**: Identify dorsomedial cutaneous nerve branches - typically 2-3 branches crossing dorsally within 2-3mm of incision. Use loupe magnification. Gently retract branches medially or laterally with vessel loops. **Fascial layer**: Incise fascia longitudinally. Identify EHL tendon coursing distally and laterally - this is your KEY anatomical landmark. **Technical Tip**: 'I make a dorsomedial incision centered over the 1st TMT joint which I palpate as 3-4cm distal to navicular tuberosity. Under loupe magnification I identify dorsomedial cutaneous nerve branches which cross the incision in 70% of cases - I protect these with vessel loops. My key landmark is the EHL tendon which I stay MEDIAL to for safety - the dorsalis pedis artery is 15-20mm lateral between EHL and EHB.' - **Dorsomedial cutaneous nerve injury** (5-10%): Multiple small branches, use loupe magnification and gentle handling - **EHL tendon injury**: Stay medial to tendon, avoid sharp dissection near it - **Wrong level**: Variable anatomy - confirm TMT joint with palpation and fluoroscopy if needed ### Step 2: Deep Dissection and Joint Exposure **Interval development**: Develop plane MEDIAL to EHL tendon. Retract EHL laterally with small Hohmann retractor. This protects dorsalis pedis artery and deep peroneal nerve which are lateral to EHL. **Capsulotomy**: Identify TMT joint line - typically at proximal extent of medial eminence but variable. Confirm with fluoroscopy if uncertain. Incise capsule longitudinally along dorsal and medial aspects. Then make transverse capsular incisions creating T-shaped or H-shaped capsulotomy for maximal exposure. **Exposure**: Place small Hohmann retractors medially and laterally (staying medial to EHL). Plantarly directed retractors risk medial plantar neurovascular bundle - avoid excessive plantar retraction. Expose entire TMT joint dorsally and medially. **Synovectomy**: Remove synovium from joint to improve visualization of cartilage surfaces. **Technical Tip**: 'I develop the interval medial to EHL tendon which I retract laterally. The EHL is my safety barrier - dorsalis pedis and deep peroneal nerve are 15-20mm lateral between EHL and EHB so staying medial is safe. I perform T-shaped capsulotomy and tag the capsule with sutures for later repair. Fluoroscopy confirms I am at the TMT joint and not the intercuneiform joint which can be confusing.' - **Wrong joint**: Intercuneiform joint lies proximal - use fluoroscopy to confirm TMT joint - **Excessive plantar dissection**: Medial plantar neurovascular bundle 10-15mm plantar to joint - do not extend dissection plantarly - **Lateral dissection**: Risk to dorsalis pedis artery and deep peroneal nerve if extending lateral to EHL ### Step 3: Joint Preparation - Cartilage Removal **Preparation philosophy**: Goal is flat, parallel, congruent surfaces with healthy bleeding cancellous bone contact. **Technique options**: **Option A: Flat cut technique (preferred)** - Use sagittal saw with narrow blade - Make perpendicular cut to metatarsal removing 2-3mm from metatarsal base surface - Make corresponding perpendicular cut removing 2-3mm from cuneiform surface - Maintain surfaces parallel and flat - Most stable configuration, easiest to achieve correct position **Option B: Curved/concave-convex technique** - Create slight concavity in one surface, convexity in other - Theoretically increases surface area - More technically demanding, risk of instability if surfaces non-congruent **Cartilage removal**: After bone cuts, use small curettes to remove all remaining cartilage fragments. Use rongeur or burr to fenestrate subchondral plate exposing cancellous bone. Avoid thermal necrosis - intermittent burr use with irrigation. **Surface preparation goals**: - Complete cartilage removal (any retained cartilage = nonunion risk) - Exposed bleeding cancellous bone (multiple punctate bleeding points) - Minimal bone resection (excessive shortening >5mm = transfer metatarsalgia) - Parallel surfaces (non-parallel = malposition) **Technical Tip**: 'I prefer flat cut technique using sagittal saw removing 2-3mm from each surface. This creates parallel flat surfaces which are most stable and easiest to position correctly. I then curette all cartilage and use small rongeur to fenestrate subchondral bone until I see punctate bleeding from cancellous bone. Critical to minimize bone resection - I aim for <5mm total shortening to prevent transfer metatarsalgia. I avoid aggressive burr use which causes thermal necrosis.' - **Excessive resection**: >5mm shortening causes transfer metatarsalgia (10-20% incidence) - **Non-parallel surfaces**: Leads to malposition (especially dorsiflexion or rotation) - **Inadequate preparation**: Retained cartilage or poor bone quality = nonunion - **Thermal necrosis**: Excessive burr use without irrigation damages bone cells ### Step 4: Provisional Reduction and Deformity Correction **Reduction maneuvers**: 1. Grasp 1st metatarsal distally 2. Translate metatarsal LATERALLY toward 2nd metatarsal (narrows IMA) 3. Derotate - correct pronation (hallux should point straight, not rotated) 4. Sagittal plane - ensure NEUTRAL or slight plantarflexion (NOT dorsiflexion) 5. Length - minimize shortening, maintain contact with lesser metatarsals **Provisional fixation**: Hold reduction with 1-2 smooth K-wires: - Insert K-wire from dorsal metatarsal into cuneiform, aiming plantar-proximal - Check does not penetrate plantar cortex (risk to neurovascular bundle) - Second K-wire for rotational control if needed **Reduction assessment checklist**: - IMA: Narrowed to <10° (aim 5-8°) - check AP fluoroscopy - Rotation: Hallux aligned, no pronation - Sagittal: NO dorsiflexion - neutral or 5° plantarflexion - check LATERAL fluoroscopy - Length: Metatarsal head aligned with lesser metatarsals, <5mm shortening **Technical Tip**: 'I provisionally reduce by translating 1st metatarsal laterally to narrow IMA to 5-8°. CRITICAL point: I actively maintain or slightly plantarflex the 1st ray because the trapezoid shape of cuneiform (wider dorsally) and gravity both promote dorsiflexion. I hold reduction with K-wires and check LATERAL fluoroscopy - this is where dorsiflexion error is seen. The 1st metatarsal should align with or be slightly below lesser rays on lateral view. Any dorsiflexion seen on lateral view must be corrected before plating.' - **DORSIFLEXION malposition** (most common error 15-20%): Cuneiform trapezoid shape and gravity promote dorsiflexion - actively prevent this - **Overcorrection**: IMA <5° or varus alignment causes hallux varus and dysfunction - **Rotational malposition**: Pronation/supination causes functional impairment - **K-wire penetration**: Plantar cortex penetration risks neurovascular bundle ### Step 5: Fluoroscopic Confirmation - MANDATORY **Imaging protocol**: AP, lateral, and oblique views with K-wires in place BEFORE plating. **AP view assessment**: - IMA corrected to <10° (measure angle between 1st and 2nd metatarsals) - Alignment: metatarsal base centered on cuneiform - No varus overcorrection - K-wire position appropriate **LATERAL view assessment** - CRITICAL: - NO DORSIFLEXION: 1st metatarsal should align with or be slightly below (plantarflexed to) 2nd-5th metatarsals - Check declination angle if able to measure - K-wire trajectory acceptable **Oblique view**: - Joint reduction confirmed - No interposition **Correction of malposition**: If ANY malposition identified, remove K-wires and reposition BEFORE plating. Much harder to correct after plate fixation. **Technical Tip**: 'I obtain AP, lateral, and oblique fluoroscopy images with provisional K-wires. The LATERAL view is most important - this is where I identify dorsiflexion malposition which is the most common error. On lateral view, I draw a line along axis of 1st metatarsal and along axis of lesser metatarsals - the 1st should align with or be slightly below (plantar to) the others. Any elevation (dorsiflexion) of 1st ray must be corrected. I also confirm IMA <10° on AP and check alignment on oblique. If position suboptimal, I remove K-wires and reposition now before plating.' - **Proceeding with malposition**: Must correct NOW before plating - much harder after definitive fixation - **Inadequate imaging**: All 3 views needed - lateral view often skipped but most important - **Misinterpretation**: Ensure you can clearly see 1st metatarsal-cuneiform relationship ### Step 6: Definitive Fixation - Plate Application **Plate selection**: Dorsomedial locking plate (TMT-specific, anatomic, low-profile) - Typical size: 6-hole plate (3 screws proximal in cuneiform, 3 screws distal in metatarsal) - Pre-contoured to anatomic shape - Locking screws provide angular stability **Plate positioning**: - Position plate on dorsomedial surface spanning TMT joint - Ensure plate sits flush on bone (may need minor contouring) - Avoid overhang medially (painful prominence) - Center plate so equal screw distribution proximal and distal to joint **Screw insertion sequence**: 1. First screw in cuneiform (proximal fragment) - typically non-locking 2. Check fluoroscopy - any position adjustment needed 3. First screw in metatarsal (distal fragment) - typically non-locking 4. Check fluoroscopy - final adjustment opportunity 5. Remaining locking screws alternating proximal/distal 6. Check each screw does not penetrate adjacent joints (2nd TMT, intercuneiform, naviculocuneiform) **Screw length**: - Proximal screws: 16-22mm typically (through cuneiform, may engage opposite cortex) - Distal screws: 18-24mm (through metatarsal base) - Measure carefully - penetration of plantar cortex risks neurovascular bundle **Technical Tip**: 'I use a low-profile dorsomedial locking plate which is current gold standard - meta-analyses show nonunion rate 5-8% with plates versus 10-15% with screws alone. I position the anatomic plate on the dorsomedial surface ensuring it sits flush. I insert first screw in cuneiform, check position on fluoro, then first screw in metatarsal giving me last chance for adjustment. Then I complete remaining locking screws. I carefully measure screw lengths - too long risks plantar neurovascular bundle, too short loses fixation. All screws are bicortical for maximum purchase.' - **Plate prominence**: Medial overhang or thick plate causes pain and hardware removal (10-15%) - **Screw penetration**: Adjacent joints (naviculocuneiform, intercuneiform, 2nd TMT) or plantar neurovascular bundle - **Loss of reduction**: During plate application - check fluoroscopy after each step - **Inadequate fixation**: Unicortical screws or stripped threads in osteoporotic bone ### Step 7: Supplemental Lag Screw Fixation **Lag screw rationale**: Provides interfragmentary compression supplementing plate neutralization. Biomechanical studies show improved stability. **Lag screw technique**: 1. Drill hole from dorsal metatarsal base toward plantar cuneiform 2. Trajectory: Aim from dorsolateral to plantarmedial (perpendicular to fusion plane) 3. Overdrill near cortex (metatarsal side) with larger diameter to create lag effect 4. Measure depth carefully 5. Insert 3.5mm or 4.0mm partially threaded screw 6. Tighten to achieve compression (feel resistance increase, see surfaces approximate) 7. Check fluoroscopy for screw position and compression **Screw position**: - Outside plate if possible for independent fixation - If through plate, ensure compatible with plate hole design - Avoid intra-articular penetration of naviculocuneiform or intercuneiform joints **Alternative: Plantar plate** - Biomechanically superior (tension side fixation) - Requires separate plantar incision and more extensive dissection - Higher technical difficulty - Consider for revision cases or if dorsal plate undesirable **Technical Tip**: 'I supplement the dorsomedial plate with a lag screw from dorsal metatarsal to plantar cuneiform for interfragmentary compression. I overdrill the near cortex to create lag effect. Trajectory is dorsolateral to plantarmedial aiming perpendicular to fusion plane. I use 3.5mm or 4.0mm partially threaded screw and tighten until I feel compression. I measure screw length carefully - too long penetrates plantar structures, too short loses compression. Some surgeons prefer plantar plating which is biomechanically ideal but I find dorsomedial plate plus lag screw gives excellent results with lower technical difficulty.' - **Screw too long**: Penetrates plantar soft tissue injuring medial plantar neurovascular bundle - **Screw trajectory**: Intra-articular penetration of adjacent joints - **Loss of reduction**: Screw insertion can displace fragments - check fluoroscopy - **Inadequate compression**: Threads not engaging far cortex or screw too short ### Step 8: Bone Grafting (Selective) **Indications for bone graft**: - Revision surgery with bone defect - Osteoporotic bone - Smokers (>10 cigarettes/day) - Large surfaces with gap >2mm after compression - Diabetes or other nonunion risk factors **Graft options**: **Local bone** (most common): - Use bone resected from TMT joint preparation - Morselized into small fragments - Pack around fusion site peripherally - No additional incision required **Iliac crest autograft**: - Gold standard for biology - Harvest from anterior or posterior iliac crest - Cancellous or corticocancellous - Donor site morbidity (pain, hematoma, nerve injury) **Allograft**: - Cancellous chips or demineralized bone matrix - No donor site morbidity - Potential for disease transmission (very low with modern screening) **Bone substitutes**: - Calcium phosphate or sulfate - Osteoconductive scaffolds - Expensive, mixed evidence **Application technique**: - Pack bone graft around periphery of fusion site AFTER fixation - Avoid interposition between fusion surfaces (prevents compression) - Does not replace adequate preparation and stable fixation **Technical Tip**: 'Bone graft is optional in primary Lapidus with good bone quality - I achieve excellent union rates without it. However, I consider bone graft for high-risk patients: smokers, diabetics, osteoporosis, or revision cases. I use local bone from the resection, morselizing it and packing around the fusion site peripherally. This augments biology without donor site morbidity. I avoid interposing graft between fusion surfaces which would prevent compression. For revision cases with large defects I may use iliac crest autograft.' - **Graft interposition**: Between fusion surfaces prevents compression and delays union - **Donor site morbidity**: Iliac crest harvest - chronic pain 5-10%, hematoma, LFCN injury - **Overpacking**: Excessive graft can displace fragments or cause soft tissue tension ### Step 9: Distal Adjunct Procedures (Selective) **Assessment for distal procedures**: After TMT fusion, assess residual hallux valgus at MTP joint. Usually Lapidus corrects entire deformity. Consider distal procedures if: - Residual HVA >15° after TMT correction - DMAA >10° (intra-articular deformity) - Hallux valgus interphalangeus **Akin osteotomy** (most common adjunct): - Medial closing wedge osteotomy of proximal phalanx - Corrects hallux valgus interphalangeus - Separate 2-3cm medial incision over proximal phalanx - Remove medial wedge, close with screw or K-wire **Medial eminence resection**: - Usually not needed if deformity corrected - If medial prominence persists: limited resection through TMT incision or separate MTP incision - Avoid excessive resection weakening medial column **Lateral soft tissue release**: - Rarely needed with Lapidus (correction at TMT eliminates tension) - If severe contracture: release adductor hallucis and lateral capsule through separate incision - Risk of AVN to metatarsal head if combined with extensive medial dissection **Technical Tip**: 'Usually Lapidus alone corrects the hallux valgus deformity as it addresses the apex. But I assess the hallux position after TMT fixation - if residual valgus at MTP or if DMAA is >10°, I add an Akin osteotomy. This is a medial closing wedge of proximal phalanx through a small medial incision. I avoid extensive distal soft tissue releases as they risk AVN and are usually not needed when TMT hypermobility is addressed. I also avoid excessive medial eminence resection which can weaken the medial column.' - **AVN risk**: Extensive circumferential dissection at MTP level disrupts blood supply - **Overcorrection**: Combining multiple procedures can cause hallux varus - **MTP instability**: Excessive lateral release or medial eminence resection ### Step 10: Final Imaging and Wound Closure **Final fluoroscopy - 3 views**: - **AP**: IMA <10°, hardware well-positioned, no intra-articular screws - **Lateral**: NO dorsiflexion, 1st ray aligned with or plantar to lesser rays, appropriate hardware position - **Oblique**: Joint reduction confirmed, compression achieved, no interposition **Closure sequence**: 1. Copious irrigation (3L normal saline minimum) 2. Deflate tourniquet and achieve hemostasis (bipolar cautery) 3. Repair capsule with 2-0 or 3-0 absorbable suture (Vicryl) - provides additional stability 4. Close subcutaneous layer with 3-0 absorbable (reduces dead space) 5. Skin: 4-0 or 5-0 monofilament interrupted or subcuticular (nylon or Monocryl) 6. Sterile dressing with gentle compression 7. Apply posterior splint or CAM boot maintaining alignment **Dressing technique**: - Adaptic or non-adherent layer over incision - Fluffed gauze for gentle compression - Webril wrap from toes to mid-calf - Posterior splint with ankle at neutral, foot at neutral or slight plantarflexion - Overwrap with elastic bandage - Alternative: Removable CAM boot for compliant patients **Technical Tip**: 'I obtain final fluoroscopy in 3 views confirming excellent alignment - IMA <10° on AP, no dorsiflexion on lateral, good hardware position. I irrigate copiously with 3L normal saline. I repair the capsule with absorbable sutures which provides additional stability. Meticulous skin closure is important - wound complications occur in 5-10% especially in smokers, diabetics, or peripheral vascular disease. I apply well-padded posterior splint or CAM boot maintaining alignment with strict non-weight bearing instructions.' - **Wound complications**: Dehiscence, delayed healing (5-10% incidence, higher in diabetics/smokers) - **Hematoma**: Inadequate hemostasis or excessive compression - **Loss of reduction**: Inadequate immobilization allowing displacement before union - **Compartment syndrome**: Rare but possible with excessive dressing compression - ensure splint allows swelling ### Additional Complications **Recurrent Deformity** (<5% with proper technique) - Rare if TMT fusion eliminates hypermobility - Usually indicates nonunion (continued mobility) or concurrent untreated pathology - Management: Assess for nonunion (CT scan), address underlying cause, revision if needed **DVT/PE** (1-3%) - Risk from prolonged immobilization and non-weight bearing - Prevention: Chemical prophylaxis in high-risk patients (consider aspirin 325mg daily or LMWH), early ankle ROM exercises, calf pumps, compression stockings - Management: Standard anticoagulation protocols **Infection - Deep** (1-2%) - Presentation: Persistent pain, fever, elevated inflammatory markers, drainage, radiographic changes - Prevention: Appropriate antibiotic prophylaxis (cefazolin), sterile technique, minimize operative time - Management: Surgical debridement, culture-directed IV antibiotics 6 weeks, retain hardware if fusion incomplete, remove hardware if fusion solid and infection persistent **Complex Regional Pain Syndrome** (1-2%) - Severe pain, vasomotor changes, trophic changes, functional impairment - Prevention: Minimize surgical trauma, early mobilization of uninvolved joints, multimodal analgesia - Management: Multidisciplinary - physical therapy, sympathetic blocks, medications (gabapentin, tricyclics), psychology referral **Adjacent Joint Arthritis** (Long-term concern) - Intercuneiform, naviculocuneiform, or 2nd TMT arthritis from altered mechanics - Develops over years to decades - Usually asymptomatic or mild - Management: Conservative initially (orthotics, NSAIDs), fusion extension if severe symptomatic ## Immediate Postoperative Period (0-2 weeks) **Immobilization**: Well-padded posterior splint or removable CAM boot in neutral ankle position, neutral or slight plantarflexion of forefoot **Weight bearing**: STRICT non-weight bearing (NWB) - crutches or walker, no weight on operative foot **Elevation**: Keep foot elevated above heart level 23 hours/day for first 2 weeks to minimize swelling **Ice**: Ice packs 20 minutes on, 20 minutes off while awake **Pain management**: - Multimodal analgesia: scheduled acetaminophen 1000mg TDS - Opioids: Short course (5-7 days) oxycodone 5-10mg PRN, minimize use - Gabapentin 300mg TDS for neuropathic component - NSAIDs: Avoid first 6 weeks (impair bone healing) unless low-dose aspirin for DVT prophylaxis **DVT prophylaxis**: - Low-risk patients: Mechanical (calf pumps, ankle ROM exercises, compression stockings) - High-risk patients (obesity, smoking, prior DVT, prolonged surgery): Consider aspirin 325mg daily or LMWH **First post-op visit** (10-14 days): - Remove surgical dressing - Assess wound healing - Remove sutures if non-absorbable (typically 14 days) - Apply new dressing and splint or CAM boot - Continue NWB ## Weeks 2-6: Protected Healing Phase **Immobilization**: Transition to removable CAM boot if not already (allows hygiene) **Weight bearing**: Continue STRICT NWB - fusion site is healing but not strong enough for load **Wound care**: Once sutures removed and wound sealed, allow gentle washing (soap and water), pat dry, keep dressing **Exercises**: - Ankle ROM exercises (gastrocnemius stretching, ankle pumps) - prevents stiffness - Knee and hip ROM - NO hallux or forefoot ROM (fusion site) **Radiographs**: At 6 weeks - AP, lateral, oblique **6-week assessment** - CRITICAL decision point: - Clinical exam: Tenderness at TMT fusion site (less expected as healing), wound healed, neurovascular status - Radiographs: Evidence of early union (bridging trabeculae, callus formation, no lucency progression) - CT scan: If radiographs equivocal - shows trabecular bridging better than X-ray **Decision**: - **If progressing to union**: Advance to protected weight bearing - **If questionable**: Extend NWB 2-4 more weeks, repeat imaging - **If nonunion concern**: Consider CT scan, may need extended NWB or bone stimulator ## Weeks 6-12: Progressive Weight Bearing Phase **Weight bearing progression** (if union progressing at 6 weeks): - Weeks 6-8: Partial weight bearing (25-50% body weight) in CAM boot with crutches - Weeks 8-10: Weight bearing as tolerated (50-75%) in boot with 1 crutch - Weeks 10-12: Full weight bearing in boot, wean crutches **Immobilization**: Continue CAM boot until 12 weeks **Exercises**: - Continue ankle ROM - Begin gentle hallux ROM (passive) at 8-10 weeks - Toe curls, marble pickup for intrinsic strength - Stationary bike (no resistance) from 8 weeks **Radiographs**: At 12 weeks - assess union **12-week assessment**: - Clinical exam: Pain-free weight bearing expected, no tenderness at TMT - Radiographs: Solid union (bridging trabeculae 3+ cortices, no lucency, callus maturation) - CT scan: If radiographs equivocal **Decision**: - **If solid union**: Transition to supportive shoes, gradual return to activities - **If incomplete union but progressing**: Continue boot 2-4 more weeks, repeat imaging - **If nonunion**: See complications section - may need revision surgery ## Months 3-6: Return to Activities **Footwear**: Transition from boot to supportive athletic shoes or walking shoes (wide toe box, rigid sole initially) **Weight bearing**: Full weight bearing in shoes **Exercises**: - Progress strengthening (resistance band, heel raises) - Proprioception (single leg balance, wobble board) - Gradual return to impact activities (walking → jogging → running) - Swimming/cycling excellent during this phase **Activity restrictions**: - No high-impact activities until 4 months (running, jumping) - No sports until 6 months - Individual progression based on symptoms and radiographic union **Radiographs**: At 6 months - confirm solid union and alignment maintenance **6-month assessment**: - Expected outcome: Solid fusion, full pain-free weight bearing, return to regular shoes, minimal activity limitations - Alignment maintained (IMA <10°, no dorsiflexion) - No hardware complications ## Long-term Follow-up (>6 months) **Return to full activities**: Unrestricted activities at 6 months if solid union and asymptomatic **Hardware removal**: Consider at 12-18 months if symptomatic prominence (10-15% require removal) **Annual radiographs**: First 2 years to monitor for late complications (adjacent joint arthritis, hardware issues) **Long-term outcomes**: - Union rate: 92-95% with modern fixation - Patient satisfaction: 85-90% - Recurrence: <5% (fusion eliminates TMT hypermobility) - Return to sports: 90% return to pre-injury level by 12 months ## Troubleshooting Common Post-op Issues **Persistent pain at 6 weeks**: - Normal to have some tenderness - Concerning if sharp pain with weight bearing, night pain, or worsening pain - Consider delayed union or nonunion - obtain CT scan - May need extended NWB, bone stimulator, or revision **Transfer metatarsalgia developing 3-6 months**: - Suggests dorsiflexion malunion or excessive shortening - Obtain weight-bearing lateral radiograph - Conservative management initially (metatarsal pads, orthotics) - May require surgical correction if severe **Wound issues**: - Dehiscence: Local wound care, exclude infection - Persistent drainage: Concern for deep infection - labs (CBC, CRP, ESR), consider aspiration - Early recognition and treatment crucial **Numbness**: - Dorsomedial cutaneous nerve neuropraxia common (5-10%) - Usually improves over 3-6 months - Desensitization techniques if dysesthetic - Neuroma excision if painful persistent neuroma plantar plate > crossed lag screws (decreasing stability and union rates)", "Minimize shortening: <5mm bone resection total to prevent transfer metatarsalgia (10-20% if excessive)", "TMT hypermobility testing: stabilize hindfoot, dorsally/plantarly translate 1st metatarsal - >9mm is pathologic and Lapidus indication", "Union optimization: smoking cessation mandatory, diabetes control (HbA1c <7%), bone graft for high-risk, strict NWB 6 weeks" ] }, { heading: "Complications", points: [ "Nonunion (5-8% plate, 10-15% screws, 20-30% smokers) - CT diagnosis at 12 weeks, revision with bone graft if symptomatic", "DORSIFLEXION malunion (10-20%, most common error) - devastating transfer metatarsalgia, requires revision - PREVENTION KEY", "Transfer metatarsalgia (10-20%) - from dorsiflexion or >5mm shortening - orthotics or revision if severe", "Hallux varus (2-5%) - overcorrection IMA <5° - flexible: splinting, rigid: reverse Akin or MTP fusion", "Hardware prominence (10-15%) - remove after union (12-18 months), use low-profile plates, ensure flush positioning" ] }, { heading: "Post-op Protocol", points: [ "0-6 weeks: STRICT non-weight bearing, CAM boot or cast, elevation, ankle ROM only", "6-week assessment: XR ± CT to assess union, advance to PWB if progressing", "6-12 weeks: Progressive weight bearing (25% → 50% → full) in boot if union progressing", "12-week assessment: XR confirm union, transition to supportive shoes if solid fusion", "3-6 months: gradual return to activities, full activities at 6 months if asymptomatic" ] }, { heading: "Exam Tips", points: [ "CLASSIC EXAM QUESTION: 'Why dorsiflexion most common error?' - Answer: cuneiform trapezoid (wider dorsally), gravity, focus on AP neglecting lateral", "Know evidence: plate nonunion 5-8% vs screws 10-15%, Cottom/Roth biomechanical studies, quote specific numbers", "Hypermobility assessment: >9mm dorsoplantar TMT translation = pathologic, compare contralateral, use stress radiographs if needed", "Lapidus vs distal procedures: Lapidus corrects at APEX (TMT), distal corrects at MTP - Lapidus for severe IMA/hypermobility/revision", "Revision dorsiflexion malunion: excise dorsal cuneiform bone, plantarflex and refuse, or distal metatarsal dorsal closing wedge osteotomy" ] } ]} /> ## References 1. **Cottom JM, Vora AM. Fixation of Lapidus arthrodesis with a plantar interfragmentary screw and medial locking plate: a report of 88 cases**. J Foot Ankle Surg. 2013;52(4):465-469. doi:10.1053/j.jfas.2013.02.025 - Landmark study demonstrating low nonunion rate (3%) with plate fixation - Plantar screw plus medial plate superior to crossed screws alone 2. **Roth KE, Peters J, Schmidtmann I, et al. Hypermobility of the first tarsometatarsal joint: a critical analysis of various measurement techniques**. Foot Ankle Int. 2014;35(6):581-588. doi:10.1177/1071100714528493 - Defines pathologic hypermobility as >9mm dorsoplantar translation - Stress radiography more reliable than clinical examination alone 3. **Gutteck N, Wohlrab D, Zeh A, et al. Comparative results of percutaneous chevron osteotomy versus Lapidus arthrodesis for hallux valgus deformity**. Foot Ankle Int. 2013;34(11):1529-1533. doi:10.1177/1071100713492761 - Lapidus superior for severe deformity (IMA >15°) and hypermobile first ray - Lower recurrence rate with Lapidus (2% vs 8% for chevron) 4. **Ellington JK, Myerson MS, Coetzee JC, Stone RM. The use of the Lapidus procedure for recurrent hallux valgus**. Foot Ankle Int. 2011;32(7):674-680. doi:10.3113/FAI.2011.0674 - 89% good to excellent outcomes in revision setting - Addresses failed distal procedures by correcting at apex of deformity 5. **Klos K, Gueorguiev B, Mückley T, et al. Stability of medial locking plate and compression screw versus two crossed screws for lapidus arthrodesis: a cadaver study**. Foot Ankle Int. 2010;31(2):158-163. doi:10.3113/FAI.2010.0158 - Biomechanical study demonstrating plate superior to crossed screws - Dorsomedial locking plate provides greater resistance to dorsiflexion and plantarflexion moments 6. **King CM, Richter J, Tullis B. First metatarsocuneiform arthrodesis with crossed screws or locking plate: a comparative study**. J Foot Ankle Surg. 2014;53(4):437-443. doi:10.1053/j.jfas.2014.03.014 - Nonunion rate: 12% with screws versus 5% with plates - Hardware removal more common with plates (15%) but union rate superior 7. **Blitz NM, Lee T, Williams K, et al. Early weight bearing after modified Lapidus arthodesis: a multicenter review of 80 cases**. J Foot Ankle Surg. 2010;49(4):357-362. doi:10.1053/j.jfas.2010.04.002 - Early weight bearing (2-4 weeks) safe with rigid plate fixation - No increase in nonunion or malunion with early WB protocol 8. **Kopp FJ, Patel MM, Levine DS, Deland JT. The modified Lapidus procedure for hallux valgus: a clinical and radiographic analysis**. Foot Ankle Int. 2005;26(11):913-917. doi:10.1177/107110070502601103 - 93% union rate with crossed screw fixation - Dorsiflexion malunion most common complication (18%) causing transfer metatarsalgia 9. **Patel S, Ford LA, Etcheverry J, et al. Modified Lapidus arthrodesis: rate of nonunion in 227 cases**. J Foot Ankle Surg. 2004;43(1):37-42. doi:10.1053/j.jfas.2003.11.009 - Smoking increased nonunion from 5% to 25% - Age >50 years and diabetes also risk factors for nonunion 10. **Sangeorzan BJ, Hansen ST Jr. Modified Lapidus procedure for hallux valgus**. Foot Ankle. 1989;9(6):262-266. doi:10.1177/107110078900900602 - Classic description of technique and indications - Emphasis on hypermobility as key indication distinguishing Lapidus from distal procedures

Lapidus Procedure (1st TMT Arthrodesis for Hallux Valgus)

Lapidus Procedure (1st TMT Arthrodesis for Hallux Valgus)