import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Knee joint communication: enters surgical field with tendon retraction. Must be protected and closed watertight. Violation causes hemarthrosis and increases infection risk.** **Crosses surgical field obliquely from medial to lateral, 3-5cm below joint line. At risk during lateral retinacular exposure. Injury causes anterior knee numbness.** **Branch of femoral artery, runs with saphenous nerve medially. At risk during medial retinacular exposure. Control with electrocautery before vessel retraction.** **Risk of drill penetration into articular cartilage when creating transosseous tunnels. Aim tunnels to exit at inferior pole - use fluoroscopy if needed.** **Risk of PATELLAR FRACTURE during tunnel drilling, especially in osteoporotic bone. Use 2.5-3mm drill, create 3 tunnels minimum 10mm apart. Avoid bicortical drilling on articular side.** ## Quadriceps vs Patellar Tendon Rupture - Key Demographics | Feature | Quadriceps Tendon Rupture | Patellar Tendon Rupture | |---------|---------------------------|-------------------------| | **Age** | Older patients (>40 years) | Younger patients (<40 years) | | **Mechanism** | Eccentric contraction, stumbling | Athletic activity, jumping | | **Risk Factors** | DM, CRF, steroids, fluoroquinolones | Previous surgery, tendinopathy, PRP | | **Location** | 1-2cm proximal to patella | Inferior pole patella | | **Patella Position** | PATELLA BAJA (low riding) | PATELLA ALTA (high riding) | | **Gap** | Palpable above patella | Palpable below patella | | **Incidence** | More common (3:1) | Less common | | **Bilateral** | More common (especially CRF) | Less common | **EXAM KEY**: Remember - Quadriceps rupture = patella BAJA (patella drops DOWN when tendon above retracts). Patellar tendon rupture = patella ALTA (patella rides HIGH when tendon below ruptures). This radiographic finding is pathognomonic. ## Transosseous Repair - Gold Standard Technique ### Tunnel Placement - Create **3 longitudinal tunnels** in superior pole of patella - Drill with **2.5-3mm drill bit** - Space tunnels **minimum 10mm apart** to prevent fracture - Entry at superior pole, exit at mid-patella (not articular surface) - Use curette to create gentle curve avoiding articular penetration ### Suture Configuration - Use **#2 or #5 non-absorbable braided suture** (Ethibond, FiberWire) - **Krackow locking suture** technique in tendon stump - Pass 2 limbs of each suture through separate tunnels - Creates 3-point fixation across patella width ### Tensioning - Tie sutures with knee in **FULL EXTENSION** - Check passive flexion achieves **90 degrees** without repair gapping - Over-tensioning causes stiffness; under-tensioning causes weakness - Sutures tied over **bone bridge at inferior patella** **EXAM KEY**: Transosseous repair has HIGHER pullout strength than suture anchors, especially in osteoporotic bone. This is the gold standard technique and must be described precisely in the viva. ## When to Augment Quadriceps Tendon Repair ### Indications for Augmentation 1. **Chronic ruptures** (>2-3 weeks old) 2. **Poor tissue quality** (atrophic, fatty infiltration) 3. **Revision repairs** (previous failed repair) 4. **Bilateral ruptures** in high-risk patients 5. **Large gap requiring shortening** (tendon retraction) ### Augmentation Options | Technique | Advantages | Disadvantages | |-----------|------------|---------------| | **Semitendinosus autograft** | Biological, no donor site morbidity at knee | Hamstring weakness | | **Synthetic tape augmentation** | Strong, no harvest morbidity | Foreign body, cost | | **Achilles allograft** | Large graft, no donor morbidity | Disease transmission, cost | | **Polypropylene mesh** | Load-sharing, cheap | Foreign body reaction | | **Wire cerclage** (historical) | Simple | Wire breakage, palpable, outdated | ### Semitendinosus Weave Technique 1. Harvest semitendinosus through separate incision 2. Weave graft in figure-8 through patella tunnels 3. Suture to native tendon stump 4. Provides load-sharing during healing **EXAM KEY**: For chronic ruptures, the native tendon is often contracted and poor quality. Augmentation is NOT optional - it is required to achieve a durable repair. Semitendinosus autograft is the most commonly examined augmentation technique. ## Suture Anchor Technique ### When to Consider Anchors - Young patient with good bone quality - Acute rupture with healthy tissue - Surgeon preference/experience - Faster surgical time ### Anchor Placement - **2-3 anchors** in superior pole of patella - Place in **line parallel to articular surface** - Use **5.5mm or larger** anchors - Avoid bicortical purchase (articular damage) ### Advantages vs Transosseous - Faster technique - Less risk of patellar fracture during tunnel creation - No need for curette/tunnel creation ### Disadvantages vs Transosseous - **Lower pullout strength** in osteoporotic bone - Anchor failure in poor bone - Higher cost (implant expense) - Less load-sharing across patella **EXAM KEY**: While suture anchors are acceptable, you should always mention that transosseous repair is the GOLD STANDARD with highest pullout strength. In osteoporotic patients (common in quadriceps rupture population), transosseous is preferred. **Patient Position**: Supine on radiolucent table, small bump under knee for slight flexion (10-20°) **Tourniquet**: Non-sterile thigh tourniquet, inflated to 300mmHg after exsanguination **Surgical Approach**: Midline longitudinal incision from mid-thigh to tibial tubercle (15-20cm) **Setup Verification**: Fluoroscopy available for tunnel placement confirmation if needed ### Step 1: Exposure and Tendon Identification Make **midline longitudinal incision** from mid-thigh extending to tibial tubercle. Identify the **retracted proximal tendon stump** - may be 5-10cm proximal in complete ruptures due to muscle contraction. Evacuate the suprapatellar hemarthrosis. Assess medial and lateral **retinacular tears** which often accompany the tendon rupture. **Technical Tip**: The tendon stump retracts significantly due to quadriceps muscle contraction. Extend your incision proximally if stump not immediately visible. The suprapatellar pouch will be full of blood clot - irrigate thoroughly. - Missing retracted tendon stump - extend incision proximally - Inadequate hemarthrosis evacuation - causes postoperative stiffness ### Step 2: Tendon Stump Debridement **Debride frayed and necrotic tissue** from tendon stump back to healthy, bleeding tendon. Assess tissue quality - poor quality with fatty infiltration suggests need for augmentation. Preserve as much length as possible. In chronic ruptures, stump may be contracted and require mobilization. **Technical Tip**: Good quality tendon has visible longitudinal collagen fiber pattern. Poor quality appears yellow, friable, or fatty. If in doubt about tissue quality, plan for augmentation. - Over-debridement shortening tendon excessively - Under-debridement leaving necrotic tissue (weak repair) ### Step 3: Patellar Surface Preparation **Decorticate the superior pole of patella** with rongeur or burr to expose bleeding cancellous bone. This creates a healing surface for tendon-to-bone incorporation. Mark the positions for **3 transosseous tunnels** - central, medial, and lateral - minimum 10mm apart. **Technical Tip**: Decorticating the superior patella creates a bleeding bone bed that promotes tendon healing. Similar principle to rotator cuff footprint preparation. - Tunnels too close together risking patellar fracture - Articular surface penetration with drill ### Step 4: Transosseous Tunnel Creation Drill **3 longitudinal tunnels** using 2.5-3mm drill from superior pole to mid-patella (NOT through articular surface). Use curette to create gentle curve in tunnels, directing exit to anterior/inferior patella. Pass **looped suture retriever** through each tunnel from inferior to superior. **Technical Tip**: Use fluoroscopy if concerned about articular surface penetration. The drill should exit at the inferior pole of patella anteriorly, NOT through the joint surface. - Patellar fracture from tunnels (osteoporotic bone) - Articular cartilage damage from drill penetration ### Step 5: Krackow Suture Placement Place **Krackow locking sutures** in the quadriceps tendon stump using heavy non-absorbable suture (#2 or #5 FiberWire/Ethibond). The Krackow technique creates **interlocking loops** that grip the tendon and don't pull through. Use 3 sutures, one for each tunnel. **Technical Tip**: The Krackow suture is the gold standard for tendon repair - the locking loops prevent the suture from pulling through the tendon under tension. Each passage should take a 5mm bite of tendon. - Sutures too superficial (will pull out) - Incomplete locking pattern (suture slides) ### Step 6: Suture Passage and Tensioning Pass suture limbs through patellar tunnels using the suture retrievers. **Reduce the tendon stump** down to the decorticated patella surface. With knee in **FULL EXTENSION**, sequentially tension and tie sutures over bone bridge at inferior patella. Confirm tendon-bone apposition. **Technical Tip**: CRITICAL - Tie sutures with knee in FULL EXTENSION. Test that knee achieves 90° passive flexion without repair gapping. If repair gaps at 90°, it is too tight and will cause extensor lag. - Over-tensioning causing stiffness (patella baja) - Under-tensioning causing extensor lag ### Step 7: Retinacular Repair Palpate and repair **medial and lateral retinacular tears** with interrupted sutures. These tears contribute to extensor mechanism dysfunction and should not be ignored. Repair in layered fashion - synovium/capsule, then retinaculum. **Technical Tip**: Retinacular tears are often missed! Palpate systematically along both sides of the patella. Unrepaired retinacular defects cause ongoing weakness even with intact tendon repair. - Missing retinacular tears (persistent weakness) - Damage to infrapatellar nerve branch during lateral repair ### Step 8: Intraoperative Assessment and Closure Test **active straight leg raise** to confirm repair integrity. Verify **passive ROM** achieves 90° flexion. Close suprapatellar pouch watertight if violated. Irrigate wound and close in layers over drain. Apply **hinged knee brace locked in extension**. **Technical Tip**: If patient cannot perform straight leg raise intraoperatively, the repair is inadequate. Consider augmentation or revision of fixation before closing. - Closing with inadequate repair (patient will fail) - Not testing extension - missing failed repair **Phase 1 (Weeks 0-2)**: Hinged knee brace LOCKED IN EXTENSION for weight bearing and sleep. Passive ROM 0-30° flexion only. Quadriceps isometrics and SLR in brace. Full weight bearing in locked brace. **Phase 2 (Weeks 2-6)**: Progressive passive ROM - increase 10-15° per week targeting 90° by week 6. Continue brace for weight bearing. Active assisted ROM exercises. **Phase 3 (Weeks 6-12)**: Unlock brace for ambulation once achieving 90° flexion. Begin active extension exercises. Progress strengthening. Wean from brace by week 8-10. **Phase 4 (Months 3-6)**: Full ROM exercises. Progressive resistance training. Return to activities at 4-6 months depending on strength recovery (>80% of contralateral side). 1. Ciriello V, Gudipati S, Tosounidis T, et al. 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J Orthop Trauma. 1998;12(4):273-279. 9. Maffulli N, Del Buono A, Spiezia F, et al. Less-invasive semitendinosus tendon graft augmentation for the reconstruction of chronic ruptures of the quadriceps tendon. Knee Surg Sports Traumatol Arthrosc. 2014;22(6):1443-1450. 10. Lighthart WA, Cohen DA, Levine RG, et al. Suture anchor versus suture through tunnel fixation for quadriceps tendon rupture: a biomechanical study. Orthopedics. 2008;31(5):441.