import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Wraps around fibular neck laterally, 2-3cm distal to fibular head. **Protection**: Avoid lateral dissection beyond preserved hinge (5-10mm from lateral cortex), gentle opening without excessive valgus force, monitor for traction injury during correction **Location**: Posterior to proximal tibia, 1-2cm posterior to posterior tibial cortex at osteotomy level. **Protection**: Place Hohmann retractor posteriorly around tibia before osteotomy, protect with retractor during saw cuts, avoid deep posterior saw penetration **Location**: Medial subcutaneous, beneath sartorius fascia near hamstring harvest site. **Protection**: Use separate incisions for HTO and hamstring harvest (3-4cm separation), gentle dissection medially, identify and protect during pes anserinus exposure **Location**: Superficial MCL fibers anterior to pes anserinus insertion on proximal medial tibia. **Protection**: Elevate pes anserinus distally preserving MCL anterior fibers, avoid excessive periosteal stripping, maintain MCL integrity for knee stability **Location**: Tibial ACL tunnel must avoid HTO plate - plate spans osteotomy site 3-4cm distal to joint line. **Protection**: Plan HTO osteotomy 3-4cm distal to joint (avoid ACL tunnel interference), tibial tunnel starts 2-3cm proximal to plate, fluoroscopy confirms no hardware conflict **Patient Position**: Supine on radiolucent table. Bump under ipsilateral hip for neutral rotation. Tourniquet thigh (optional, deflate before fixation). Fluoroscopy essential (mini C-arm). Leg holder or foot triangle for ACL portion. Ensure access to entire lower limb for cable alignment measurement. **Surgical Approach**: Arthroscopic for ACL assessment and reconstruction. Mini-open anteromedial approach for HTO. Hamstring harvest incision for ACL graft. Separate incisions to avoid wound complications. **Incision**: Anteromedial HTO incision (5-7cm oblique) - 3-4cm distal to joint line, starting medial to tibial tubercle extending posteromedially. Separate hamstring harvest incision (3-4cm oblique) over pes anserinus to reduce wound complications. Standard arthroscopy portals (anterolateral, anteromedial). ### Absolute Indications - **ACL deficiency with varus malalignment >3-5° mechanical axis** - isolated ACL reconstruction has 20-40% failure rate in varus knees vs 5-10% in neutral, HTO correction protects graft from varus thrust - **ACL tear with medial compartment early OA** (Outerbridge 2-3, Kellgren-Lawrence 1-2) in young active patient (<55-60 years) - combined procedure offloads medial compartment while providing stability - **ACL tear with medial meniscal deficiency** (root tear, subtotal meniscectomy, irreparable meniscal tear) - HTO offloads medial compartment protecting remaining meniscus and ACL graft - **Revision ACL reconstruction in varus knee** - if primary ACL failed due to varus malalignment, revision requires HTO to correct biomechanics ### Relative Indications - **ACL tear with varus 2-3° AND medial symptoms** - borderline varus with medial pain, younger age, high activity demands - **Prophylactic HTO with ACL in varus 3-5°** - prevent future medial OA progression and graft failure in young athletic patient ### Contraindications **Absolute**: - Advanced medial compartment OA (Outerbridge grade 4, Kellgren-Lawrence 3-4, bone-on-bone) - consider UKA or TKA instead - Inflammatory arthropathy (rheumatoid arthritis, psoriatic arthritis) - not mechanical problem, disease will progress - Infection (active or recent septic arthritis) - stage infection treatment before elective osteotomy - Severe peripheral vascular disease - healing impairment, ischemic complications - Patient unwilling/unable to comply with protected weight-bearing protocol - HTO requires 6-12 weeks TTWB for union **Relative**: - Age >60-65 years - arthroplasty may be more appropriate, though biological age matters more than chronological - Obesity (BMI >35) - increased nonunion risk, mechanical failure, worse outcomes - Smoking - 3-4x increased nonunion risk, must quit 6-8 weeks preoperatively - Osteoporosis/poor bone quality - fixation failure risk, consider bone health optimization - Flexion contracture >15° - difficulty achieving full extension, affects ACL tunnel placement - Patellofemoral arthritis - may worsen with valgus correction or slope change - Ligamentous laxity (hypermobile patient) - HTO correction less predictable, consider other stabilization ### Imaging Assessment **Full-Length Standing Alignment Radiographs (MANDATORY)**: - **Mechanical axis deviation (MAD)**: Distance in mm from center of knee to mechanical axis line (hip center to ankle center) - medial (varus) or lateral (valgus) - **Mechanical axis angle**: Angle formed by femoral mechanical axis (hip center to knee center) and tibial mechanical axis (knee center to ankle center) - normal 0° ± 3° - **Medial proximal tibial angle (MPTA)**: Angle between tibial plateau and tibial shaft mechanical axis - normal 85-90° - Calculate correction needed to reach **Fujisawa point (62-65% across plateau)** = 3-5° valgus **Standard Weight-Bearing Radiographs**: - AP, lateral, skyline views - assess compartment OA severity - Flexion PA (Rosenberg view) - sensitive for medial cartilage loss - Grade OA severity: **Kellgren-Lawrence** (0-4), joint space narrowing, osteophytes, sclerosis - Measure **posterior tibial slope** on lateral view - normal 7-10°, can increase to 10-12° to aid ACL **MRI Knee**: - Confirm ACL tear (complete vs partial, stump quality, femoral/tibial insertion remnants) - **Meniscal pathology**: Root tears, degenerative tears, extrusion - plan repair vs debridement - **Cartilage grading**: Outerbridge 0-4 each compartment (medial, lateral, patellofemoral) - Bone marrow edema pattern - indicates overload zones - Posterior slope measurement (sagittal sequences) ### Wedge Size Calculation **Miniaci Method**: 1. Draw current mechanical axis on full-length alignment film 2. Draw target mechanical axis through Fujisawa point (62-65% across plateau) 3. Measure angle difference = correction needed (typically 3-5°) 4. Use formula: **Wedge opening (mm) = 1mm per 1° correction** (approximate) 5. Typical opening: **7-12mm at anterior cortex** for 3-5° valgus correction **Digital Templating**: - Use specialized software (TraumaCad, OrthoView, Sectra) for precise calculation - Accounts for posterior slope change if desired - Can simulate final alignment and hardware position ### Patient Counseling - **Complex dual procedure** - longer surgery (3 hours), dual healing requirements (bone + graft) - **Protected weight-bearing 6-12 weeks** - toe-touch only initially, progressive to full at 12 weeks - **Prolonged return to sport** - 9-12 months minimum (NOT standard ACL 6-9 months) - **Success rates 80-90%** at 5 years if appropriate indications - **Hardware removal** - elective at 18-24 months if symptomatic (30-50% patients) - **Future arthroplasty** - more complex after HTO but still feasible if needed ### Critical Sequence Pearls 1. **Diagnostic arthroscopy FIRST** - confirm ACL tear, grade cartilage (ensure medial not grade 4), assess menisci, address concurrent pathology 2. **NEVER drill ACL tunnels before HTO** - valgus correction shifts tibial anatomy, tunnel position will be wrong if drilled pre-HTO 3. **Hamstring harvest through SEPARATE incision** - 3-4cm separation from HTO incision reduces wound complication risk 4. **HTO osteotomy 3-4cm distal to joint** - LOW ENOUGH to avoid ACL tunnel interference and intra-articular fracture 5. **Preserve lateral hinge** - 5-10mm intact lateral cortex provides stability, allows controlled opening 6. **Cable method for alignment** - electrocautery cable from femoral head to ankle confirms mechanical axis through Fujisawa point intraoperatively 7. **ACL femoral tunnel first (post-HTO)** - femur unchanged by HTO, drill femoral tunnel anatomically 8. **ACL tibial tunnel ADJUSTED for HTO** - start proximal to plate (2-3cm above), may need lateral start point, fluoroscopy confirms no hardware conflict ### Graft Length Pearl - **Need LONGER graft for combined procedure** - HTO opening increases tibial length by wedge size (7-12mm) - Harvest hamstrings to at least **24-26cm** (vs standard 22-24cm for isolated ACL) - Ensure adequate length for both femoral and tibial fixation after HTO correction ### Posterior Slope Management - **Maintain or slightly increase slope** to 10-12° total (aids ACL function) - Avoid excessive increase (>12-15°) - paradoxically causes ACL graft laxity - Check lateral fluoroscopy during opening - measure anterior vs posterior opening - **Asymmetric opening intentional** if slope change desired (more posterior opening = increased slope) ### Spacer/Graft Options - **Autograft** (iliac crest tricortical) - gold standard for biology, morbidity from second site - **Allograft** (femoral head, tibia, etc) - no donor site morbidity, infection/incorporation risk - **Synthetic wedges** (tricalcium phosphate, PEEK, metal) - reliable size, no biology - **No spacer** - some techniques allow gap to fill naturally, risk of collapse (less common) ### HTO Plate Options **Locking Plate Systems** (preferred): - **TomoFix** (DePuy Synthes) - most common, anatomic design, fixed angle locking screws - **Puddu plate** - original HTO plate design - **Contour Lock** (Smith & Nephew) - low-profile option - **iBalance** (Arthrex) - patient-specific instrumentation option **Plate Characteristics**: - Medial locking plate spanning osteotomy - 3-4 proximal locking screws supporting opened gap (metaphyseal purchase) - 3-4 distal locking screws in diaphysis (cortical purchase) - Low-profile design to minimize soft tissue irritation - Can add lateral plate if hinge fractures (10-15% incidence) ### ACL Fixation Options **Femoral Fixation**: - **Suspensory** (EndoButton, TightRope) - most common, flips on far cortex - **Interference screw** - PEEK or bioabsorbable, in femoral tunnel alongside graft - **Hybrid** (suspensory + interference) - popular for combined HTO-ACL for extra security **Tibial Fixation**: - **Interference screw** - most common, divergent from graft, must avoid HTO plate (>2-3cm separation) - **Suture post/button** - on anterior tibia, backup option if screw risks hardware conflict - Ensure adequate separation from HTO hardware during planning ### Hardware Removal - **Timing**: Elective at 18-24 months after HTO fully healed - **Indications**: Plate prominence, soft tissue irritation, patient preference - **Rate**: 30-50% patients undergo removal - **Outcome**: Symptoms improve, no loss of correction if bone healed ### Phase 1: Immediate Postoperative (0-6 weeks) **Weight-Bearing**: TOE-TOUCH ONLY (10-20kg max) - CRITICAL for HTO bone healing **Brace**: Locked in extension for ambulation, unlock for ROM exercises **ROM**: 0-90° gentle passive and active-assisted - avoid deep flexion (stresses HTO and ACL) **Exercises**: - Quadriceps sets (isometric, no resistance) - Straight leg raises (all planes) - Ankle pumps, calf stretches - Patellar mobility **DVT Prophylaxis**: Chemoprophylaxis (LMWH or DOAC) PLUS mechanical (TED stockings, calf pumps) **Goals**: Protect HTO, prevent stiffness, quadriceps activation ### Phase 2: Early Healing (6-12 weeks) **Weight-Bearing**: PROGRESSIVE based on radiographic healing - 25% body weight at 6 weeks (if callus forming) - 50% body weight at 8 weeks - 75% body weight at 10 weeks - WBAT by 12 weeks ONLY after radiographic union confirmed **Brace**: Wean as weight-bearing progresses **ROM**: Full (0-135°) **Exercises**: - Stationary bike (light resistance) - Pool therapy (buoyancy-assisted) - Closed-chain exercises (mini squats, leg press light) - Continue quadriceps strengthening **Goals**: HTO union, ACL graft incorporation, restore ROM ### Phase 3: Strengthening (3-6 months) **Weight-Bearing**: Full as tolerated **Exercises**: - Progressive resistance training (quadriceps, hamstrings, hip abductors) - Proprioception (single-leg balance, wobble board) - Functional training (step-ups, lunges, lateral movements) - Swimming, elliptical (low-impact cardio) **Goals**: Restore strength, proprioception, functional movement patterns ### Phase 4: Sport-Specific Training (6-9 months) **Activities**: - Light jogging progression (if asymptomatic, HTO healed, ACL stable) - Sport-specific drills (cutting, pivoting progression) - Plyometrics (jumping, landing mechanics) **Criteria**: - Radiographic HTO union confirmed - Negative Lachman, pivot shift - 80%+ quadriceps strength vs contralateral (isokinetic testing) **Goals**: Prepare for return to sport ### Phase 5: Return to Sport (9-12 months) **Criteria** (ALL must be met): - HTO fully healed on radiographs (cortical bridging, remodeling) - ACL stable on examination (Lachman, pivot shift, KT-1000) - Full ROM (0-135°+) - 90%+ strength quadriceps AND hamstrings vs contralateral - Functional testing passed (hop tests, Y-balance, agility) - Psychological readiness (ACL-RSI score) **Return**: Gradual progression to full sport participation **Timeline**: Minimum 9-12 months (NOT standard ACL 6-9 months) ### Step 1: Understanding Combined HTO-ACL Rationale Understanding Combined HTO-ACL Rationale: BIOMECHANICAL CONCEPT: VARUS alignment increases MEDIAL compartment load (60-80% medial vs 20-40% lateral) and creates VARUS THRUST during gait. ACL deficiency in varus knee has: 1) Increased ANTERIOR tibial translation (ACL role), 2) Increased MEDIAL translation (varus thrust), 3) Accelerated MEDIAL OA from overload. ISOLATED ACL reconstruction in VARUS knee often FAILS from ongoing varus thrust and medial overload. COMBINED SURGERY RATIONALE: HTO corrects alignment to VALGUS (shifts load laterally), reducing medial compartment load and varus thrust. This PROTECTS ACL graft from ongoing stress AND protects medial compartment from OA progression. INDICATIONS for combined procedure: 1) ACL + varus >3-5°, 2) ACL + medial OA early stages, 3) ACL + medial meniscal deficiency, 4) Revision ACL in varus knee. SEQUENCING: Single-stage (HTO + ACL same surgery) vs two-stage (HTO first, ACL later). Single-stage preferred - one recovery, addresses both problems, ACL protected from day one. **Technical Tip**: EXAM KEY: 'Isolated ACL reconstruction in varus knee often fails because varus thrust continues to stress graft and medial compartment. I perform combined HTO-ACL to: 1) Correct alignment to valgus (offload medial, reduce varus thrust), 2) Protect ACL graft from ongoing stress, 3) Protect medial compartment and meniscus. Single-stage is preferred - one recovery, immediate benefit.' - Isolated ACL in varus >5° = high failure risk (20-40% vs 5-10% in neutral) - Isolated HTO without ACL in unstable knee = ongoing instability - Two-stage surgery = two recoveries, delayed return, higher cost - Patient expectation mismatch (complex surgery, long recovery) ### Step 2: Preoperative Planning & Alignment Analysis Preoperative Planning & Alignment Analysis: IMAGING ASSESSMENT: 1) ALIGNMENT RADIOGRAPHS: Full-length standing AP (hip-knee-ankle), measure mechanical axis deviation (MAD - mm from knee center), mechanical axis angle (hip center to ankle center), medial proximal tibial angle (MPTA, normal 85-90°). 2) STANDARD RADIOGRAPHS: Weight-bearing AP/lateral/skyline, flexion PA (Rosenberg), assess cartilage (joint space, osteophytes, sclerosis - Kellgren-Lawrence grade). 3) MRI: ACL status, menisci, cartilage grading (Outerbridge), bone marrow edema, posterior tibial slope (sagittal). ALIGNMENT CALCULATION: Current mechanical axis → Target mechanical axis (FUJISAWA POINT: 62-65% across tibial plateau from medial = 3-5° valgus). Use MINIACI METHOD or digital templating. Calculate WEDGE SIZE needed (mm of opening at osteotomy site). Typical 7-12mm opening for 3-5° correction. POSTERIOR SLOPE: Maintain or slightly increase (avoid excessive - causes graft laxity). Normal slope 7-10°. Can increase to 10-12° to aid ACL. **Technical Tip**: EXAM KEY: 'Preop planning is CRITICAL. I measure mechanical axis on full-leg standing films - calculate current MAD and angle. Target is FUJISAWA POINT: 62-65% across plateau or 3-5° valgus - offloads medial compartment and protects ACL. I use Miniaci method or digital templating to determine wedge opening needed, typically 7-12mm. I check posterior slope on lateral - maintain or slightly increase to 10-12° to aid ACL.' - Under-correction (inadequate offloading, varus thrust persists, ACL graft failure) - Over-correction (excessive valgus causes lateral compartment overload, patellofemoral problems) - Excessive posterior slope increase (paradoxically causes ACL graft laxity) - Operating without formal alignment films = guessing correction ### Step 3: Diagnostic Arthroscopy & ACL Assessment Diagnostic Arthroscopy & ACL Assessment: Standard AL and AM portals. Systematic arthroscopy: 1) ACL - confirm complete tear vs partial, stump quality, femoral/tibial insertion remnants. 2) MENISCI - medial meniscus extrusion? Root tear? Lateral meniscus OK? Repair vs debride vs transplant. 3) CARTILAGE - Outerbridge grading of medial/lateral compartments, patellofemoral joint. Confirm medial OA not advanced (grade 4 = consider UKA instead). 4) LOOSE BODIES, synovitis. DOCUMENT with photos. Address concurrent pathology: meniscal repair/debridement, chondroplasty, loose body removal. DO NOT create ACL tunnels yet (wait until after HTO - tunnels may shift with correction). **Technical Tip**: EXAM KEY: 'I perform diagnostic arthroscopy first to confirm ACL tear and assess compartments. I carefully grade medial cartilage - if grade 4 (bone-on-bone), patient may be better with UKA than HTO. I repair medial meniscus if possible (HTO protects repair). CRITICAL: I do NOT drill ACL tunnels yet - HTO will shift tibial tunnel position, so ACL tunnels AFTER HTO.' - Drilling ACL tunnels before HTO (tunnel position shifts with correction) - Proceeding with HTO in advanced medial OA (grade 4 = consider UKA) - Missing meniscal pathology requiring repair - Inadequate cartilage assessment ### Step 4: Hamstring Graft Harvest for ACL Hamstring Graft Harvest for ACL: HAMSTRING HARVEST: Oblique incision (3-4cm) over pes anserinus, 3cm distal and 2cm medial to tibial tubercle. This incision is SEPARATE from HTO incision to reduce wound complication risk. Incise sartorial fascia. Identify gracilis (superior) and semitendinosus (inferior) tendons. Strip with closed stripper to at least 24-26cm length (need longer than standard ACL due to HTO opening). Prepare 4-strand graft on back table: whipstitch both ends, measure diameter (target 8-10mm), pretension on graft board. Keep moist. Alternative: BPTB or quadriceps autograft (some prefer bone-bone healing with HTO bone work). Allograft option if patient prefers but autograft preferred for biology. **Technical Tip**: EXAM KEY: 'I harvest hamstrings through SEPARATE incision from HTO incision to reduce wound complications. I need LONGER graft than standard ACL (24-26cm minimum) because HTO opening increases tibia length slightly. I prepare 4-strand graft, 8-10mm diameter, and pretension. Some surgeons prefer BPTB for bone-to-bone healing with concurrent HTO bone work.' - Shared incision with HTO = wound complication risk - Graft too short (HTO increases tibial length) - Saphenous nerve/vein injury medially - Graft amputation from accessory bands ### Step 5: HTO Osteotomy - Anteromedial Approach HTO Osteotomy - Anteromedial Approach: INCISION: 5-7cm oblique incision, 3-4cm distal to joint line, starting 1cm medial to tibial tubercle extending posteromedially over pes anserinus insertion. DISSECTION: Incise fascia, elevate pes anserinus distally (can preserve or release), protect MCL superficial fibers anteriorly. EXPOSE PROXIMAL TIBIA medial surface. Retract pes muscles posteriorly. Insert Hohmann retractor POSTERIORLY around tibia (protects popliteal vessels) and LATERALLY (protects lateral soft tissues and peroneal nerve). Fluoroscopy to confirm location. MARK OSTEOTOMY: 3-4cm distal to medial joint line (avoid proximal tibial fixation zones for ACL), parallel to joint line. Osteotomy from medial cortex aimed toward FIBULAR HEAD on lateral side, STOPPING 5-10mm from lateral cortex (PRESERVE HINGE). **Technical Tip**: EXAM KEY: 'HTO incision is separate from ACL harvest. I expose medial proximal tibia, retract pes posteriorly, place Hohmann retractors posterior (protect popliteal vessels) and lateral (protect soft tissues). I mark osteotomy 3-4cm distal to joint, aimed at fibular head. Critical to START LOW ENOUGH to avoid ACL tunnel interference and PRESERVE LATERAL HINGE for stability.' - Osteotomy too proximal = interferes with ACL tunnels, intra-articular fracture risk - Popliteal vessels injury posteriorly (Hohmann retractor protects) - Common peroneal nerve injury laterally (careful lateral dissection) - MCL superficial fibers injury (impacts knee stability) - Violation of lateral hinge = unstable osteotomy, lateral translation ### Step 6: Osteotomy Execution & Hinge Preservation Osteotomy Execution & Hinge Preservation: TECHNIQUE: Multiple techniques - saw, osteotomes, or both. 1) OSCILLATING SAW: Create ANTERIOR and POSTERIOR cuts from medial cortex, parallel to joint, aiming at fibular head on lateral side. Cuts stop 5-10mm from lateral cortex. 2) OSTEOTOMES: Place osteotomes between saw cuts, gently spread to create opening. Protect hinge. Alternative: MULTIPLE DRILLING: 4.5mm drill holes along osteotomy line, then complete with osteotome (less heat, preserves biology). HINGE PRESERVATION is CRITICAL: Lateral cortex must stay intact for stability. Hinge width 5-10mm. Check fluoroscopy - ensure cuts stop short of lateral cortex. If hinge breaks: can still proceed but need fixation on lateral side (plate or screws) for stability. **Technical Tip**: EXAM KEY: 'I use oscillating saw for anterior and posterior cuts, parallel to joint, aiming at fibular head laterally. Critical to STOP 5-10mm from lateral cortex to preserve hinge. Hinge provides stability during opening and healing. I check with fluoroscopy. If hinge breaks (10-15% incidence), I add lateral plate or screws for stability but outcomes still good.' - Hinge fracture/violation = unstable osteotomy (can salvage with lateral fixation) - Intra-articular fracture (osteotomy too proximal) - Posterior cortex blowout (saw too deep posteriorly) - Thermal necrosis from saw (irrigate, use sharp blade) - Peroneal nerve injury if lateral dissection ### Step 7: Gradual Opening & Alignment Correction Gradual Opening & Alignment Correction: OPENING: Use graduated osteotome spreaders or specialized HTO opening instruments. Open GRADUALLY in 1-2mm increments. Monitor with FLUOROSCOPY: AP view shows opening gap, lateral view shows posterior slope. Use CABLE METHOD: Electrocautery cable from femoral head center to ankle center - check passes through FUJISAWA POINT (62-65% across plateau). Alternative: Use alignment rod under fluoroscopy. WEDGE SIZE: Typical 7-12mm opening at anterior cortex for 3-5° valgus correction. If using WEDGE SPACER/ALLOGRAFT: insert trial spacers to confirm size, then insert definitive spacer (metal, PEEK, allograft, or tricalcium phosphate). If NOT using spacer: leave gap for bone ingrowth. POSTERIOR SLOPE: Check lateral fluoroscopy - maintain or slight increase slope (7-12° total). Avoid anterior opening exceeding posterior (creates extension). **Technical Tip**: EXAM KEY: 'I open osteotomy gradually using spreaders, checking alignment with cable method under fluoroscopy - cable from femoral head to ankle should pass through Fujisawa point (62-65% across plateau). Typical opening 7-12mm at anterior cortex for 3-5° valgus. I check posterior slope on lateral view - maintain or slightly increase to 10-12°. I use spacer (allograft or synthetic) to prevent collapse.' - Under-opening = inadequate correction, persistent varus, ACL failure - Over-opening = excessive valgus, lateral compartment overload, patellofemoral issues - Asymmetric opening (anterior vs posterior) = slope change (can be intentional) - No spacer = gap collapse (though some techniques allow this) - Hinge fracture during opening ### Step 8: HTO Plate Fixation HTO Plate Fixation: MEDIAL LOCKING PLATE: Use HTO-specific plate (Tomofix, Puddu, etc.) with locking screws. Plate spans osteotomy medially. POSITIONING: Plate centered on medial tibia, proximal screws in metaphysis, distal screws in diaphysis. TECHNIQUE: Hold plate with K-wires temporarily. Drill and insert LOCKING SCREWS: Typically 3-4 proximal, 3-4 distal, bicortical. Proximal screws in locking holes support opened gap. Check screw length - no intra-articular penetration (fluoroscopy), no lateral cortex excessive penetration. SPACER: If used, insert bone graft or synthetic wedge into gap before plate fixation to maintain correction and enhance healing. Check FINAL ALIGNMENT with cable/fluoroscopy: Mechanical axis through Fujisawa point (62-65%). STABILITY: Osteotomy should be stable - no toggle. If unstable, add lateral plate (rare if hinge intact). **Technical Tip**: EXAM KEY: 'I fix with medial locking plate - HTO-specific design. I hold reduction with K-wires, then insert locking screws - 3-4 proximal supporting the opened gap, 3-4 distal for stability. I insert spacer (bone graft or synthetic) to prevent collapse and enhance healing. Final fluoroscopy check: mechanical axis through Fujisawa point, no intra-articular screws, stable construct.' - Intra-articular screw penetration (check fluoroscopy) - Screw too long laterally = peroneal nerve, soft tissue irritation - Plate malposition = loss of correction - Inadequate screw purchase = fixation failure - No spacer = gap collapse, loss of correction (some techniques accept this) ### Step 9: ACL Femoral Tunnel - Post-HTO ACL Femoral Tunnel - Post-HTO: NOW perform ACL reconstruction (HTO completed and fixed). ARTHROSCOPY: Return to arthroscopic portals (AL, AM). Re-examine knee - confirm HTO didn't violate joint (rare). FEMORAL TUNNEL: Use ANATOMIC technique. Drill through ANTEROMEDIAL portal at 110-120° knee flexion. AIM: Center of femoral ACL footprint - use resident's ridge (lateral intercondylar ridge) and bifurcate ridge as landmarks. Position: 1-2mm anterior to over-the-top, on lateral wall of notch. Drill guide wire, confirm position arthroscopically and fluoroscopically (lateral view), over-drill with cannulated reamer matching graft diameter (typically 8-10mm). Depth: 25-30mm for suspensory fixation, deeper if interference screw. ENSURE tunnel does NOT conflict with HTO plate (usually no issue - femoral tunnel is femur, HTO is tibia). **Technical Tip**: EXAM KEY: 'After HTO fixed, I proceed to ACL. I drill femoral tunnel through AM portal at 110-120° flexion using anatomic technique - center of footprint using resident's ridge as landmark. Tunnel 8-10mm matching graft diameter. HTO doesn't affect femoral tunnel since it's on femur, but tibial tunnel position DOES change from HTO correction.' - Posterior wall blowout (tunnel too posterior) - Short tunnel (tunnel too anterior) - Non-anatomic position = graft failure - Confluence with HTO hardware (rare) ### Step 10: ACL Tibial Tunnel - Adjusted for HTO ACL Tibial Tunnel - Adjusted for HTO: TIBIAL TUNNEL is CRITICAL and ADJUSTED for HTO. HTO correction SHIFTS tibial tunnel position: Valgus correction shifts tunnel slightly LATERALLY and ANTERIORLY. Must account for this. TECHNIQUE: Use TIBIAL GUIDE at 55° angle (or adjust based on slope). AIM: Center of ACL footprint on tibia (just anterior to tibial spine, lateral to medial spine). START POINT: Typically anteromedial, PROXIMAL to HTO plate (2-3cm above plate) to avoid hardware. May need to start slightly LATERAL compared to standard ACL to avoid HTO plate. Drill guide wire, confirm position ARTHROSCOPICALLY (footprint center) and FLUOROSCOPICALLY (avoid HTO plate, proper angle). Over-drill with cannulated reamer. ENSURE: 1) Tunnel avoids HTO plate, 2) Tunnel exits at proper footprint position, 3) Tunnel parallel to Blumensaat's line in extension. **Technical Tip**: EXAM KEY: 'Tibial tunnel is ADJUSTED for HTO - valgus correction shifts anatomy. I use tibial guide aimed at footprint center but start point is PROXIMAL to HTO plate (2-3cm above) to avoid hardware. I may need to start slightly lateral. I check fluoroscopy - tunnel must avoid plate, exit at footprint, parallel to Blumensaat's. This is technically challenging part of combined surgery.' - Tunnel collision with HTO plate (plan trajectory carefully) - Tunnel too anterior = graft impingement - Tunnel too posterior = vertical graft - Non-anatomic footprint = graft failure - Fracture through HTO or tunnel site (rare) ### Step 11: ACL Graft Passage & Femoral Fixation ACL Graft Passage & Femoral Fixation: GRAFT PASSAGE: Pass sutures retrograde through tibial tunnel, through knee, out femoral tunnel. Pull graft into tibial tunnel, through knee, into femoral tunnel. ENSURE: Graft not twisted, graft at aperture of both tunnels, adequate graft length (remember HTO increased tibia length slightly - need longer graft). FEMORAL FIXATION: Use SUSPENSORY device (EndoButton, TightRope) - flip on far cortex of femur, pull graft tight, confirm button flipped (resistance, fluoroscopy). Alternative: Interference screw or cross-pin. Hybrid fixation (suspensory + interference) popular for combined procedure to ensure robust fixation in setting of HTO bone work. **Technical Tip**: EXAM KEY: 'I pass graft through tunnels ensuring no twist. Graft must be LONGER than standard ACL because HTO increased tibial length. For femoral fixation, I use suspensory device - flip button on far cortex, pull tight. Some surgeons add interference screw (hybrid) for extra security in combined procedure with HTO bone work nearby.' - Graft too short (HTO increased length) - Graft twisted - Button not flipped - Graft laceration during passage ### Step 12: ACL Graft Tensioning & Tibial Fixation ACL Graft Tensioning & Tibial Fixation: GRAFT CYCLING: Cycle graft 20-30 times through full ROM to pre-tension and eliminate creep. TENSIONING: Tension graft with knee at 20-30° flexion with manual posterior drawer force. TIBIAL FIXATION: Most common = INTERFERENCE SCREW inserted through tibial tunnel alongside graft. Screw divergent from graft (parallel causes laceration). ENSURE: 1) Screw avoids HTO plate (usually 2-3cm separation), 2) Screw parallel to tunnel, 3) Full extension possible without impingement. Alternative: Suture post or button fixation on anterior tibia. FINAL ASSESSMENT: Full ROM especially extension, no impingement, Lachman negative, pivot shift negative, HTO alignment maintained. **Technical Tip**: EXAM KEY: 'I cycle graft 20-30 times, then tension at 20-30° flexion. Tibial fixation with interference screw - must ensure screw is DIVERGENT from graft and AVOIDS HTO plate (2-3cm separation). I confirm full extension without impingement and negative Lachman/pivot. This combined procedure protects ACL from varus thrust and protects medial compartment.' - Screw collision with HTO plate - Screw lacerating graft (must diverge) - Inadequate screw purchase - Loss of extension (catastrophic - re-do surgery) - Residual instability ### Step 13: Final Assessment & Closure Final Assessment & Closure: COMPREHENSIVE CHECK: 1) ALIGNMENT: Cable/fluoroscopy confirms mechanical axis through Fujisawa point (62-65%), 2) HTO: Stable fixation, plate positioned correctly, no intra-articular screws, 3) ACL: Full ROM especially extension, stable Lachman and pivot, no impingement, graft well-tensioned, 4) MENISCUS: Repairs stable if performed, 5) KNEE: Full ROM 0-130°+, no varus/valgus laxity, stable patellofemoral tracking. DEFLATE tourniquet (if used), ensure hemostasis. DRAIN: Consider drain for HTO site (controversial). CLOSURE: Close HTO incision in layers - periosteum if possible, subcutaneous, skin. Close ACL harvest site. Close arthroscopy portals. Compressive dressing. Knee brace in extension. **Technical Tip**: EXAM KEY: 'Final check is critical: Alignment through Fujisawa point (fluoroscopy), HTO stable, ACL stable with full extension and negative Lachman. I deflate tourniquet for hemostasis. I may use drain at HTO site. I close in layers and apply brace in extension. Post-op protocol is PROTECTIVE - both HTO (bone healing) and ACL (graft healing) need protection.' - Misalignment unrecognized (under/over-correction) - Loss of extension - ACL instability - Hemarthrosis from HTO bone work - Wound complication (two incisions near each other) ### Step 14: Postoperative Rehabilitation - Dual Protocol Postoperative Rehabilitation - Dual Protocol: COMPLEX REHAB balancing HTO bone healing and ACL graft healing. PHASE 1 (0-6 weeks): TOE-TOUCH weight-bearing ONLY (10-20kg max) - HTO bone needs protected healing. Brace locked in extension for ambulation. ROM exercises 0-90° (avoid deep flexion - stresses HTO and ACL). Quadriceps sets, SLR, ankle pumps. DVT prophylaxis (chemoprophylaxis + mechanical). PHASE 2 (6-12 weeks): Progressive weight-bearing - 25% at 6 weeks, 50% at 8 weeks, 75% at 10 weeks, WBAT by 12 weeks (AFTER HTO healing confirmed on radiographs). ROM to full. Stationary bike (light), pool therapy. PHASE 3 (3-6 months): Strengthening, proprioception, functional training. No impact yet. Swimming, elliptical. PHASE 4 (6-9 months): Sport-specific training. Light jogging at 6-9 months if asymptomatic. PHASE 5 (9-12 months): Gradual return to full sport at 9-12 months if: HTO healed (radiographs), ACL stable (examination, functional testing), full strength and ROM. **Technical Tip**: EXAM KEY: 'Rehab is PROTECTIVE and PROLONGED - balancing HTO bone healing (12 weeks) and ACL graft maturation (9-12 months). CRITICAL: Toe-touch weight-bearing for 6 weeks (protect HTO), progressive to WBAT by 12 weeks only after HTO healing confirmed on X-ray. Return to sport 9-12 months minimum - both procedures need full maturation. Patient must understand this is NOT standard ACL - much longer recovery.' - Early weight-bearing = HTO nonunion or malunion - Aggressive ROM = loss of correction, ACL graft stress - Early return to sport = ACL graft failure or HTO failure - Patient non-compliance (must understand dual healing requirements) ### Step 15: Long-term Monitoring & Outcomes Long-term Monitoring & Outcomes: SURVEILLANCE: Clinical follow-up 2 weeks (wound check), 6 weeks (start weight-bearing progression), 12 weeks (confirm HTO union, progress rehab), 6 months, 12 months, 24 months, then annually. IMAGING: Radiographs (AP, lateral) at each visit: assess HTO alignment maintenance, bone union (typically 12-16 weeks), ACL tunnel widening, hardware position, compartment joint space, OA progression. MRI at 12-24 months if concerned about ACL graft or meniscal repairs. OUTCOMES: Combined HTO-ACL has 80-90% good-excellent outcomes at 5 years if patient selection appropriate. HTO corrects alignment and offloads medial compartment. ACL provides stability. TOGETHER they address varus thrust and medial overload. Better outcomes than either procedure alone in varus + ACL knee. HARDWARE REMOVAL: Can remove HTO plate at 18-24 months after bone fully healed if hardware symptomatic (patient preference). FAILURE MODES: 1) HTO nonunion (2-5%), malunion, loss of correction (under-correction or over-correction), 2) ACL graft failure (5-15% - lower than isolated ACL in varus), 3) OA progression despite correction (disease already established), 4) Wound infection, hardware failure. **Technical Tip**: EXAM KEY: 'Long-term surveillance shows combined HTO-ACL has 80-90% good outcomes at 5 years - better than isolated ACL in varus knee. HTO typically unites 12-16 weeks. ACL graft matures 9-12 months. I monitor alignment on serial radiographs - loss of correction or nonunion requires revision. Hardware removal optional at 18-24 months. This combined procedure PROTECTS both ACL graft (from varus thrust) and medial compartment (from overload) - it's the gold standard for ACL in varus knee.' - HTO nonunion (2-5% - risk factors: smoking, obesity, infection) - Loss of correction (under or over) requiring revision - ACL graft failure (lower than isolated ACL in varus but still 5-15%) - OA progression despite correction - Hardware complications (loosening, breakage, prominent requiring removal) - Peroneal nerve palsy (1-2% - from valgus correction or hematoma) - Compartment syndrome (rare but devastating) - DVT/PE (major surgery, limited mobility) PHASE 1 (0-6 weeks): TOE-TOUCH weight-bearing ONLY (10-20kg max) with crutches - protect HTO bone healing. Brace locked in extension for ambulation. ROM 0-90° gentle passive. Quadriceps sets (no active extension against resistance), SLR, ankle pumps. Ice, elevation. DVT chemoprophylaxis (LMWH or DOAC) + mechanical (TED stockings, calf pumps). PHASE 2 (6-12 weeks): Progressive weight-bearing - 25% at 6 weeks (if radiographs show healing), 50% at 8 weeks, 75% at 10 weeks, WBAT by 12 weeks ONLY after radiographic HTO union confirmed. ROM to full. Stationary bike light resistance, pool walking, closed-chain exercises. PHASE 3 (3-6 months): Continue strengthening, proprioception, balance, functional exercises. No impact or pivoting. Swimming, elliptical OK. PHASE 4 (6-9 months): Sport-specific training if asymptomatic and HTO fully healed. Light jogging progression. PHASE 5 (9-12 months): Gradual return to full sport if: HTO healed (radiographs), ACL stable (examination, functional testing), full ROM, 90%+ strength compared to contralateral. SURVEILLANCE: Follow-up 2 weeks, 6 weeks, 12 weeks (confirm HTO union), 6 months, 12 months, 24 months, annually. 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High Tibial Osteotomy with Concurrent ACL Reconstruction - Medial Opening Wedge

High Tibial Osteotomy with Concurrent ACL Reconstruction - Medial Opening Wedge