import { OnePagerSummary, ExamWarning, InfoCardGrid, InfoCard, MnemonicCard, EvidenceCard, VivaScenarioSection, VivaScenario, ExamCheatSheet, ContentSection, ExamPearl, SafetyAlert, NumberHighlightRow, NumberHighlight, Tabs, Tab, ComparisonTable } from '@/components/mdx' **Location**: Superficial to first dorsal compartment at Zone VI-VII level, emerges distal radius **Protection**: Identify early, retract carefully, avoid excessive lateral skin undermining **Location**: Mid-lateral line of digits, Zones I-V injuries **Protection**: Use mid-axial/Bruner incisions in digits, identify before wound extension **Location**: Volar aspect, at risk with through-and-through injuries **Protection**: Assess for associated volar injuries, explore if penetrating trauma **Location**: Zone VI over dorsal wrist, 6 compartments with critical anatomy **Protection**: Release only involved compartment, preserve adjacent retinaculum **Location**: Deep to extensor mechanism at Zones I, III, V **Protection**: Assess for joint involvement, irrigate if violated, consider arthrotomy if debris **Patient Position**: Supine with arm on radiolucent hand table. Upper arm tourniquet preferred (250 mmHg for 90 minutes max). Hand table with sterile padding and arm positioner. Zone-specific positioning: Zones I-IV hand pronated flat on table for dorsal access, Zones V-VIII forearm supinated or neutral depending on injured tendons. **Anesthesia**: General anesthesia, regional block (axillary or supraclavicular), or WALANT (Wide Awake Local Anesthesia No Tourniquet) for select cases. WALANT allows intraoperative patient participation to test repair strength and excursion but requires patient compliance. **Surgical Approach**: Zone-specific incision centered over laceration or injury site, extended longitudinally as needed for adequate exposure and safe suturing. Avoid transverse incisions over joints. **Equipment**: Magnification (loupe 2.5-3.5x or microscope), fine instruments, tendon retriever, multiple suture options (3-0/4-0 braided non-absorbable for core, 5-0/6-0 monofilament for epitendinous), splinting materials ready. **Incision**: Longitudinal incision centered over injury zone, extended proximally and distally for adequate exposure (typically 3-5 cm total). Bruner zigzag or mid-axial incisions for digital zones (I-IV) if extensile exposure needed. Straight longitudinal incisions acceptable for Zones V-VIII over dorsal hand/wrist/forearm. ## Surgical Exposure and Zone Identification ### Initial Assessment and Planning Examine wound under tourniquet control after proper preparation and draping. Assess wound characteristics: sharp laceration vs crush injury, clean vs contaminated, time since injury (primary repair <24 hours ideal, up to 7-10 days acceptable), associated injuries (nerve, artery, bone, joint). Identify injured zone using Kleinert-Verdan classification: - **Zone I**: Over DIP joint (mallet finger) - **Zone II**: Over middle phalanx (simple repair) - **Zone III**: Over PIP joint (central slip - boutonniere risk) - **Zone IV**: Over proximal phalanx (straightforward repair) - **Zone V**: Over MCP joint (sagittal band injury risk) - **Zone VI**: Over dorsal hand under extensor retinaculum (worst prognosis) - **Zone VII**: Over dorsal wrist (multiple tendons at risk) - **Zone VIII**: Distal forearm musculotendinous (good prognosis) **Zone Determines Everything**: "ODD zones (I, III, V) are Over joints and have wOrse prognosis. Zone VI is the worst overall (30-40% adhesion rate). Zones VII-VIII have best outcomes (85-95% good-excellent) if repaired properly. This knowledge guides your discussion of prognosis with patient and determines rehab protocol." ### Wound Extension Technique Extend laceration longitudinally to expose tendon ends (typically 3-5 cm total length). For digital zones (I-IV), use Bruner zigzag incisions if extensive exposure needed - preserves neurovascular structures and prevents longitudinal scar contracture. Mid-axial incisions acceptable alternative. For Zones V-VIII, straight longitudinal incisions over dorsal hand/wrist/forearm are safe and provide excellent exposure. Avoid transverse incisions over joints (cause scar contracture and limit ROM). Identify and protect dorsal sensory nerves: - **Radial sensory nerve**: Superficial at Zone VI-VII level - **DBUN** (Dorsal Branch Ulnar Nerve): Ulnar dorsal hand - **DBRUN** (Dorsal Branch Radial Ulnar Nerve): Dorsal digits ### Tendon Retrieval Retracted tendons must be retrieved before repair. Use blunt probe or dedicated tendon retriever. Retraction patterns: - **EPL**: Retracts all the way to forearm (Zone VIII) - **EDC**: Retracts to dorsal hand (juncturae may limit) - **Digital extensors**: Usually retract to hand level May need separate proximal window if tendon retracted beyond primary incision. Gentle handling prevents further trauma. Keep retrieved tendons moist with saline-soaked gauze. - Missed EPL injury in Zone VI (juncturae compensate initially, patient has weak but present thumb extension) - Excessive dissection damaging paratenon (increases adhesions) - Radial sensory nerve injury during proximal retrieval in Zone VI-VII ## Tendon Repair Fundamentals ### Tendon End Preparation Inspect tendon ends carefully. Sharp lacerations typically have clean edges requiring minimal trimming (1-2 mm maximum). Crush injuries may have frayed, devitalized tissue requiring debridement to healthy tendon - but preserve length as much as possible. Assess gap after minimal trimming. Extensor tendons have less excursion than flexors (approximately 5 cm total excursion vs 7 cm for FDP). Gaps greater than 1 cm difficult to close without undue tension. Consider advancement techniques or reconstruction if gap excessive. **Minimal Debridement Philosophy**: "Unlike flexor tendons where you may accept 5mm debridement, extensors demand length preservation. Every millimeter counts. Sharp lacerations - 1mm or less. Crushed tendons - 2mm maximum to healthy tissue. If gap still >1cm, consider central slip advancement (Zone III), FDS transfer (chronic boutonniere), or tendon graft reconstruction." ### Core Suture Techniques **Zones II-VIII** (standard repair): **Figure-of-Eight Technique** (most common for extensors): - Use 3-0 or 4-0 braided non-absorbable suture (Ethibond, FiberWire) - Pass suture transversely through tendon 5-7 mm from cut end - Cross to opposite side and pass transversely again 5-7 mm from edge - Return to starting side creating figure-8 pattern - Tie knot on dorsal surface (less irritation) - Achieves 2-4 mm purchase on each side **Modified Kessler Alternative**: - Horizontal mattress with locking loops - Similar strength to figure-of-eight - May be preferred in thicker tendons (ECRL/ECRB, Zone VII-VIII) **Zone I** (mallet finger - special considerations): - Tendon substance tear: Horizontal mattress or figure-of-eight with 4-0 suture - Bony avulsion: Extension block K-wire pinning across DIP (0.035-0.045 inch wire) - Pull-out wire suture technique: Through tendon and out dorsal nail/skin, tied over button - Large fragment (>30% articular surface): ORIF with lag screw or tension band - Inadequate purchase (<5mm): Suture pulls through, especially in thin tendons Zone I-II - Excessive gap (>2mm): Significantly increases rupture risk - Knot prominence: Causes irritation and triggering - bury knot if possible - Cheese-wiring: Too much tension on small diameter suture ### Epitendinous Suture (Critical Step) Running epitendinous suture around entire tendon circumference using 5-0 or 6-0 monofilament (nylon, Prolene). Cross-stitch or simple running technique. **Benefits of epitendinous suture**: - Adds 10-20% repair strength (more critical in extensors than flexors) - Prevents gapping at repair site during motion - Smooths repair bulk (prevents triggering) - Approximates paratenon for gliding Start at knot location from core suture, run circumferentially with small bites (1-2 mm), cross-stitch pattern provides maximum smoothness. Tie at completion, bury knot. **Epitendinous is NOT Optional**: "Studies show epitendinous suture increases repair strength by 10-20% and significantly reduces gap formation. In extensor repairs where core suture options limited by thin tendons (Zones I-II) or we accept less robust core techniques, the epitendinous becomes even more critical. I consider it mandatory in ALL extensor repairs." ## Critical Zone-Specific Techniques ### Zone I - Mallet Finger Management **Classification** (Doyle): - Type I: Closed injury - Type II: Open injury (laceration) - Type III: Open with skin loss (>1cm) - Type IV: Pediatric (physeal injury) **Decision Making**: *Non-operative* (extension splinting 6-8 weeks continuous): - Closed injury (Type I) - Articular involvement <30% of joint surface - DIP subluxation <1mm - Compliant patient *Operative indications*: - Open injury (Types II-III) - Articular fragment >30% joint surface - DIP subluxation >1mm - Failed conservative treatment (rare indication) **Surgical Techniques**: *Extension Block Pinning*: - Reduce DIP joint to neutral or slight hyperextension - Place 0.035-0.045 inch K-wire from dorsal distal phalanx, across DIP joint into middle phalanx - Leave in place 6 weeks - Prevents DIP flexion while allowing early protected motion if desired *Pull-Out Wire Suture*: - Place horizontal mattress suture through terminal extensor tendon - Pass suture through drill hole in distal phalanx - Exit through dorsal nail or skin - Tie over button on dorsal surface - Remove 6 weeks *ORIF for Large Fragments*: - 1.3mm lag screw if fragment large enough - Tension band construct (small K-wires + figure-8 wire) - Low profile plate rarely needed - Skin necrosis from splint pressure (pad DIP prominences, check skin q3-5 days initially) - Swan-neck deformity if DIP held in excessive hyperextension (>15 degrees) - Non-compliance most common cause failure (educate extensively) - Nail deformity if nail matrix injured (10-15% permanent nail ridge) ### Zone III - Central Slip and Boutonniere Prevention **Anatomy Review**: Central slip is the continuation of extensor digitorum communis inserting onto dorsal base middle phalanx. Extends PIP joint. Lateral bands pass volar to PIP axis and dorsal to DIP axis - extend DIP when central slip intact. **Boutonniere Mechanism**: Central slip rupture → lateral bands sublux volar to PIP axis → become PIP flexors instead of extensors → unopposed pull on DIP by terminal extensor → PIP flexion + DIP hyperextension deformity **Diagnosis**: - **Elson Test**: PIP flexed to 90° over table edge, patient extends PIP against resistance. If central slip ruptured, weak PIP extension + rigid DIP (lateral bands pull entirely on terminal extensor). If central slip intact, strong PIP extension + DIP flexible. **Acute Repair Technique**: - Identify central slip tear - Repair with figure-of-eight 3-0 or 4-0 non-absorbable suture - May need drill holes in middle phalanx if bony avulsion - Assess lateral band position - should be dorsal to PIP axis after repair - Test intraoperatively: passive DIP flexion should not cause PIP extension lag **Post-operative Protocol**: - PIP extended in splint or cast - **DIP MUST BE FREE** (prevents extensor lag by maintaining lateral band length) - 6 weeks strict PIP extension - Then gradual ROM with dynamic extension splinting for 2-4 weeks **Chronic Boutonniere** (>3 weeks old): - Trial closed treatment with serial static or dynamic splinting - If failed conservative: reconstruction options include: - Terminal extensor tendon turndown (Fowler technique) - Lateral band mobilization and centralization - FDS slip transfer (Snow-Littler) **Boutonniere Prevention is Everything**: "Missing a central slip injury is devastating - patient develops boutonniere over 2-4 weeks as lateral bands gradually sublux. The Elson test is critical for diagnosis. Remember: splint PIP extended but DIP MUST be FREE. Splinting the DIP in extension is a common error that causes extensor lag by shortening the oblique retinacular ligaments." ### Zone V - Sagittal Band Injury **Anatomy**: Sagittal bands are transverse fibers extending from extensor hood to volar plate and proximal phalanx at MCP level. Function: stabilize extensor tendon centrally over MCP joint dorsum. **Injury Patterns**: - Traumatic (laceration, forced flexion against resistance) - Radial sagittal band injury: less common - Ulnar sagittal band injury: MORE common (extensor subluxes ulnarly) - Most common in long and ring fingers **Clinical Presentation**: - Painful snap or clunk with MCP flexion-extension - Visible/palpable subluxation of extensor tendon - Weak MCP extension (not absent - lateral bands still function) - Extensor lag 20-40 degrees common **Acute Surgical Management**: - Identify sagittal band tear - Centralize extensor tendon over MCP - Repair sagittal band with 3-0 or 4-0 non-absorbable suture - May need pants-over-vest repair if tissue quality poor - If tendon also lacerated, repair both **Post-operative**: - MCP extension splint (0-10 degrees) - **IP joints FREE** (prevent stiffness) - 4 weeks immobilization - Then dynamic extension splinting 2 weeks - Gradual strengthening 6-8 weeks **Chronic Management**: - Trial of extension splinting 6-8 weeks - If failed: surgical options include: - Sagittal band reconstruction (juncturae, slip of EDC) - Extensor tendon centralization with retinacular sling - Cross-over EDC transfers if multiple finger involvement - Missing diagnosis (attributed to MCP sprain, patient develops chronic painful snapping) - Inadequate repair (recurrent subluxation 20-30% if tissue quality poor) - Splinting MCP in full extension (causes stiffness - use 0-10 degrees flexion) - Restrictive IP motion (MUST keep IP free to prevent stiffness) ### Zone VI - Retinaculum and Adhesion Prevention **Why Zone VI is Worst**: - Repair occurs within extensor retinaculum compartments - Limited space for tendon excursion - Scar formation between tendon and retinaculum = adhesions - 30-40% patients have significant adhesions limiting motion **Retinaculum Anatomy** (6 compartments): 1. APL, EPB 2. ECRL, ECRB 3. EPL (unique oblique course) 4. EDC, EIP 5. EDM 6. ECU **Surgical Strategy**: *Compartment Release*: - Release ONLY the involved compartment - Preserve adjacent compartments to prevent bowstringing of other tendons - Wide release of injured compartment for exposure *Repair Technique*: - Standard core + epitendinous as other zones - Ensure smooth repair (any irregularity increases adhesions) *Retinaculum Reconstruction Controversy*: **Traditional (reconstruct)**: - Prevents bowstringing - Risk of adhesions from retinaculum repair **Modern (leave open)**: - Less adhesions - Risk of bowstringing (usually minimal, cosmetic only) **Compromise (recommended)**: - Loose reconstruction allowing tendon gliding - Create window in retinaculum - Use absorbable suture for less inflammation **Zone VI Decision Making**: "I tell examiners: 'Zone VI is the worst prognosis zone. My strategy is three-fold: 1) Meticulous atraumatic technique with smooth repair, 2) Loose retinaculum reconstruction or window to balance bowstringing vs adhesions, 3) Mandatory early protected motion to reduce adhesions - I accept slightly higher rupture risk because adhesions are the greater problem here.'" **EPL Unique Considerations**: - Third compartment - oblique course around Lister's tubercle - Juncturae from EDC index allow some thumb extension even with complete EPL laceration - Test EPL specifically (thumb IP extension against resistance with wrist neutral) - Retraction to forearm common - need proximal retrieval ### Zones VII-VIII - Wrist and Forearm **Good Prognosis** (85-95% excellent outcomes): - Proximal to retinaculum (less adhesions) - Robust tendons allowing strong repair - Good soft tissue coverage - Early motion well tolerated **Multiple Tendon Injuries Common**: Identify each injured tendon: - ECRL (radial wrist extension, strong) - ECRB (central wrist extension, stronger) - EPL (thumb extension, oblique course) - EDC (finger extension, may have multiple slips) - EIP (index extension, independent) - ECU (ulnar wrist extension) **Surgical Technique**: - Generous exposure (do not underestimate extent of injury) - Standard core suture (3-0 or 4-0) + epitendinous (5-0) - Repair each tendon individually - Test each repaired tendon (passive motion, independent function) **Post-operative**: - Wrist extension 30-40 degrees - 4-6 weeks immobilization - Earlier ROM possible with strong repair (3-4 weeks) ## Quality Control and Wound Closure ### Intraoperative Repair Testing Before closure, comprehensive testing ensures repair integrity: **Gap Testing**: - Release tourniquet temporarily (check perfusion simultaneously) - Passively flex wrist to neutral - Passively flex and extend digits through full ROM - Observe repair site - should have NO gapping (>1-2mm gap requires revision) **Smooth Gliding**: - Ensure tendon glides smoothly without catching - Palpate repair site during passive motion - Any triggering sensation indicates bulky repair (needs smoothing or slight advancement) **Tension Assessment**: - Not too tight: should allow full passive flexion of wrist/digits - Not too loose: should not gap with passive motion - "Goldilocks zone" - snug but not restricting passive ROM **Independent Function** (if multiple tendons repaired): - Extend each digit passively - should move independently - Verify no inadvertent suturing of adjacent tendons together - Check juncturae - should be intact but not incorporating repair **Active Testing** (WALANT cases only): - Patient performs gentle active extension - Ultimate test of repair strength and excursion - Allows real-time adjustment of technique **Testing is Not Optional**: "The 2-minute testing phase prevents 90% of technical failures. I systematically check: 1) No gap with passive motion, 2) Smooth gliding without catch, 3) Full passive ROM possible, 4) Independent finger motion. If ANY concern, I revise before closure. Much easier than revision surgery in 6 weeks." - Gap formation: Redo core suture with better purchase or add second core suture - Triggering: Smooth epitendinous or advance tendon slightly to move bulk away from narrow zones - Over-tight: Remove core suture, allow slight lengthening, re-suture - Cannot achieve full passive ROM: Accept slight limitation or consider reconstruction ### Retinaculum Management (Zone VI) **Decision Algorithm**: *Reconstruct* if: - Significant bowstringing anticipated (young patient, strong tendons) - Multiple compartments released (need stability) - Surgeon preference for traditional approach *Leave Open* if: - Single compartment injury - Concern for adhesions high (crush injury, contamination) - Surgeon preference for modern approach *Compromise Technique* (author's preference): - Loose reconstruction with 4-0 or 5-0 absorbable suture - Leave gaps/windows in reconstruction - Allows gliding while preventing significant bowstringing - Best of both approaches ### Skin Closure **Techniques**: - 4-0 or 5-0 absorbable subcuticular preferred (no suture removal trauma) - Skin adhesive (Dermabond) over subcuticular for reinforcement - Avoid deep dermal sutures if possible (increase bulk, potential infection nidus) **Closure Principles**: - NO tension on skin edges (causes necrosis over swollen repair) - Evert wound edges slightly (prevents depressed scar) - In digital zones, ensure closure does not constrict (allow for swelling) **Dressing**: - Non-adherent layer over incision - Fluffed gauze for padding and edema control - Apply zone-specific splint immediately ## Post-operative Management and Return to Function ### Zone-Specific Splinting Protocols **Zone I (DIP)**: - DIP extension 0-5 degrees - PIP and MCP FREE - Duration: 6-8 weeks continuous, then night splinting 2-4 weeks - May use stack splint, aluminum foam splint, or custom thermoplastic **Zones II-IV (Digit)**: - Wrist extension 30-40 degrees - MCP slight flexion (20-30 degrees) or neutral - IP joints extended - Duration: 4-6 weeks **Zone III (Central Slip)** - SPECIAL: - PIP extension (0 degrees or slight hyperextension 5-10 degrees) - **DIP MUST BE FREE** (maintain lateral band length) - Duration: 6 weeks strict, then dynamic extension splinting 2-4 weeks **Zone V (Sagittal Band)**: - MCP extension (0-10 degrees flexion) - **IP joints FREE** - Duration: 4 weeks, then dynamic extension splinting 2 weeks **Zones VI-VIII (Wrist/Forearm)**: - Wrist extension 30-40 degrees - Digits in composite extension or intrinsic plus - Duration: 4-6 weeks (may shorten to 3-4 weeks if strong repair) **Splinting Errors Cause Failures**: "Know the zone-specific splint positions cold. Common errors: 1) Splinting DIP in Zone III (causes extensor lag), 2) Splinting IP joints in Zone V (causes stiffness), 3) Insufficient wrist extension in Zones VI-VIII (increased tension on repair), 4) Premature discontinuation (most common in non-compliant patients)." ### Mobilization Strategies **Static Immobilization** (traditional): - 3-4 weeks strict immobilization - Then gradual active ROM - Transition to dynamic splinting 4-6 weeks - Strengthening 6-8 weeks - Pros: Safe, 1-2% rupture rate - Cons: More stiffness (especially Zone VI), slower recovery **Early Protected Motion** (modern trend): - Relative motion protocols - Synergistic motion (wrist extension with digit flexion relaxes repair) - Early active short arc motion - Pros: Less adhesions, faster recovery, better outcomes in Zone VI - Cons: Higher rupture risk (3-5%), requires compliant patient and experienced therapist **Hybrid Approach** (most common): - Static immobilization 2-3 weeks - Transition to early protected motion 3-6 weeks - Dynamic splinting 6-8 weeks - Balances safety and outcomes **Zone VI Specific**: - Early protected motion MOST beneficial here (combats adhesions) - Accept slightly higher rupture risk - Place-and-hold exercises starting week 2-3 - Gentle passive ROM week 3-4 - Active ROM week 4-6 ### Rehabilitation Timeline **Weeks 0-2**: - Strict immobilization or very gentle protected motion (zone-dependent) - Edema control (elevation, compression) - AROM of adjacent non-immobilized joints - Patient education on splint care and precautions **Weeks 2-4**: - Continue immobilization (static protocol) OR - Initiate early protected motion (place-and-hold, short arc) - Begin gentle tendon gliding exercises if allowed - Monitor for complications (rupture, excessive pain, infection) **Weeks 4-6**: - Transition to active ROM (static protocol) OR - Progress protected motion (hybrid/early motion protocol) - Dynamic extension splinting may begin - Light functional activities (no resistance) **Weeks 6-8**: - Active ROM emphasis - Discontinue static splinting if zone allows - Continue dynamic splinting if needed - Begin light strengthening (putty, foam) - Progressive functional activities **Weeks 8-12**: - Aggressive strengthening - Resistance exercises - Sports-specific training if applicable - Gradual return to manual labor **Months 3-6**: - Return to full activities - Unrestricted use for most activities - May have 10-20 degree extensor lag (common, acceptable if functional) - Sudden loss of extension with palpable gap = RUPTURE (return to OR for re-repair if early) - Progressive loss of motion despite therapy = ADHESIONS (may need tenolysis after 3-6 months) - Extensor lag >30 degrees at 12 weeks = consider late reconstruction - CRPS symptoms (disproportionate pain, swelling, temperature/color changes) = aggressive therapy, medications ### Expected Outcomes by Zone **Zone I**: - 80-90% achieve functional DIP extension - 10-20 degree lag acceptable - 10-15% develop swan-neck if overcorrected **Zones II, IV**: - 85-95% good-excellent outcomes - Minimal extensor lag (<10 degrees) - Low complication rate **Zone III**: - 70-80% good outcomes with proper management - 15-20% develop boutonniere if central slip inadequately repaired - Chronic cases have guarded prognosis **Zone V**: - 75-85% good outcomes - 10-20 degree extensor lag common (sagittal band stretching) - Recurrent subluxation 10-15% if inadequate repair **Zone VI**: - 60-80% good outcomes (worst zone) - 30-40% develop significant adhesions - Tenolysis required in 10-20% - Early protected motion improves outcomes **Zones VII-VIII**: - 85-95% excellent outcomes (best zones) - Minimal adhesions - Good excursion - Early motion well tolerated 1. **Newport ML, Blair WF, Steyers CM Jr.** Long-term results of extensor tendon repair. *J Hand Surg Am*. 1990;15(6):961-966. doi:10.1016/0363-5023(90)90024-7 - Classic study establishing zone-specific outcomes: Zone VI worst prognosis (adhesions), Zones VII-VIII best prognosis 2. **Doyle JR.** Extensor tendons: acute injuries. In: Green DP, Hotchkiss RN, Pederson WC, eds. *Green's Operative Hand Surgery*. 4th ed. Churchill Livingstone; 1999:1950-1987. - Comprehensive review of extensor tendon anatomy, classification, and zone-specific surgical techniques 3. **Kleinert HE, Verdan C.** Report of the Committee on Tendon Injuries. *J Hand Surg Am*. 1983;8(5 Pt 2):794-798. - Original description of zone classification system (Kleinert-Verdan zones I-VIII) used universally 4. **Elson RA.** Rupture of the central slip of the extensor hood of the finger. A test for early diagnosis. *J Bone Joint Surg Br*. 1986;68(2):229-231. - Description of Elson test for central slip injury diagnosis (Zone III, boutonniere risk) 5. **Evans RB, Thompson DE.** The application of force to the healing tendon. *J Hand Ther*. 1993;6(4):266-284. doi:10.1016/S0894-1130(12)80331-5 - Biomechanical study showing epitendinous suture adds 10-20% repair strength, essential in extensor repairs 6. **Crosby CA, Wehbé MA.** Early protected motion after extensor tendon repair. *J Hand Surg Am*. 1999;24(5):1061-1070. doi:10.1053/jhsu.1999.1061 - Landmark study establishing early protected motion protocols reduce adhesions (especially Zone VI) with acceptable rupture risk 7. **Newport ML, Williams CD.** Biomechanical characteristics of extensor tendon suture techniques. *J Hand Surg Am*. 1992;17(6):1117-1123. doi:10.1016/S0363-5023(09)91079-9 - Biomechanical comparison of suture techniques: figure-of-eight and modified Kessler equivalent strength for extensors 8. **Browne EZ Jr, Ribik CA.** Early dynamic splinting for extensor tendon injuries. *J Hand Surg Am*. 1989;14(1):72-76. doi:10.1016/0363-5023(89)90062-4 - Early description of dynamic splinting protocols for extensor tendon rehabilitation, foundation of modern therapy 9. **Blair WF, Steyers CM.** Extensor tendon injuries. *Orthop Clin North Am*. 1992;23(1):141-148. - Review of complications including adhesions (30-40% Zone VI), extensor lag management, and tenolysis indications/outcomes 10. **Collocott SJ, Kelly E, Garbutt S, Karakashian K, Hadzantonis MK.** Zone VI extensor tendon injuries: should we repair the retinaculum? A systematic review. *J Hand Surg Eur Vol*. 2019;44(8):823-830. doi:10.1177/1753193419852503 - Systematic review of retinaculum reconstruction controversy: no significant difference in outcomes between reconstruction vs leaving open, modern trend toward leaving open or loose reconstruction

Extensor Tendon Repair (Zones I-VIII)

Extensor Tendon Repair (Zones I-VIII)