Tenolysis

1. High-Yield Summary

• Core Definition: Tenolysis is the surgical liberation and debridement of dense peritendinous scar tissue (adhesions) restricting active tendon excursion in the setting of preserved, supple passive joint mobility (passive range of motion exceeds active range of motion; PROM > AROM).
• Prerequisite Clinical Criteria: Successful outcomes require strict adherence to pre-surgical milestones: supple passive joint mobility (contractures resolved or addressed concurrently), a mature and pliable soft-tissue envelope (minimum 3 to 6 months post-injury or index repair), and a documented plateau in certified hand therapy of at least 4 to 6 weeks.
• Biomechanical Pulley Mandate: Preservation of critical annular pulleys (minimum 50% width of both A2 and A4 pulleys) is mandatory. Sacrificing A2 or A4 induces severe tendon bowstringing, increases work of flexion, alters the mechanical moment arm, and causes irreversible active flexion loss.
• Intraoperative Excursion Assessment: Wide-Awake Local Anesthesia No Tourniquet (WALANT) is the contemporary gold standard, allowing real-time active patient contraction to verify complete excursion (0 mm pulp-to-palmar distance) and rule out residual tethering. Under regional or general anesthesia, an objective proximal traction tenolysis maneuver through a separate forearm incision is required.
• Rehabilitation Imperative: Immediate active digital mobilization initiated within 24 to 48 hours postoperatively is essential. Delaying mobilization allows rapid fibrin re-crosslinking and collagen redeposition, precipitating recurrent adhesion formation and procedural failure.

2. Anatomy

Surgical exposure, safe release of dense fibrous tethers, and preservation of vital digital vascularity demand precise mastery of the osseofibrous digital sheath, pulley architecture, synovial compartments, and neurovascular corridors.

Flexor Sheath and Pulley Architecture

The digital flexor tendon sheath extends from the level of the metacarpophalangeal (MCP) joint to the insertion of the flexor digitorum profundus (FDP) on the base of the distal phalanx. This fibro-osseous canal is reinforced by a specialized retinacular system consisting of 5 annular pulleys (A1 to A5) and 3 cruciform pulleys (C1 to C3):

• A1 Pulley: Originates from the palmar plate of the MCP joint and proximal edge of the proximal phalanx. Can be released completely without biomechanical consequence.
• A2 Pulley: Originates from the periosteum of the proximal two-thirds of the proximal phalanx. Possesses the greatest biomechanical strength and arc length. At least 50% of the A2 pulley width must be preserved to prevent catastrophic bowstringing.
• C1 Pulley: Overlies the distal third of the proximal phalanx between A2 and A3. May be sacrificed during tenolysis to facilitate visualization.
• A3 Pulley: Located directly over the proximal interphalangeal (PIP) joint palmar plate. May be released if it tethers the repaired tendon.
• C2 Pulley: Lies between A3 and A4 over the base of the middle phalanx. Thin and expandable; can be excised if fibrosed.
• A4 Pulley: Arises from the middle third of the middle phalanx. Together with A2, constitutes the primary anti-bowstringing constraint of the digital flexor mechanism. At least 50% must remain intact.
• C3 and A5 Pulleys: Located at the distal interphalangeal (DIP) joint and base of the distal phalanx. Prevent tethering of the terminal FDP insertion.

Tendon Decussation and Camper Chiasm

Within Zone II (“no man’s land”), the flexor digitorum superficialis (FDS) bifurcates over the proximal phalanx into two distinct slips that wrap around the FDP tendon (decussation of Camper or Camper chiasm) before reuniting dorsally and re-separating to insert onto the mid-lateral ridges of the middle phalanx. The FDP tendon traverses through this split to insert onto the volar base of the distal phalanx. Dense adhesions frequently bridge the deep surface of the FDP to the periosteum of the proximal phalanx or fuse the FDP directly to the bifurcated slips of the FDS within Camper chiasm, eradicating differential glide.

Extensor Tendon Compartments and Dorsal Retinaculum

Extensor tenolysis requires meticulous knowledge of the 6 dorsal wrist compartments and the digital extensor expansion:

• Compartments 1 to 6: Compartment 1 (EPB, APL), Compartment 2 (ECRL, ECRB), Compartment 3 (EPL, curving around Lister tubercle), Compartment 4 (EDC, EIP), Compartment 5 (EDM), and Compartment 6 (ECU). Adhesions commonly tether EDC tendons beneath the thick dorsal retinaculum following distal radius or carpal fractures.
• Digital Extensor Hood (Zones IV to VII): Over the dorsum of the hand and digits, extensor tendons lack true fibrous sheaths but are interconnected by oblique juncturae tendinum. Over the proximal phalanx, the central slip inserts onto the middle phalanx base while lateral bands coalesce to form the terminal extensor tendon at the distal phalanx base. Adhesions over proximal phalangeal fractures fuse the central slip and lateral bands to dorsal bone callus, blocking both active extension and composite flexion.

Vascular Supply and the Vincula System

Digital flexor tendons receive vascularity through a dual nutritional pathway consisting of synovial fluid diffusion and segmental direct blood flow via the vincula system:

• Vinculum Breve and Longum to FDS: Arise from transverse communicating branches of the digital arteries across the floor of the digital canal, entering the dorsal aspect of the FDS near the PIP joint.
• Vinculum Breve and Longum to FDP: Arise at the middle and distal phalangeal levels, entering the dorsal surface of the FDP tendon.
• Surgical Implication: The dorsal mesotenon carrying these vincula must be strictly preserved during tenolysis. Aggressive circumferential stripping devascularizes the tendon core, predisposing to ischemic necrosis, structural attenuation, and secondary rupture during postoperative rehabilitation.

Neurovascular Danger Zones

The proper digital arteries and proper digital nerves run in close proximity along the anterolateral aspects of the flexor tendon sheath, encased within Cleland and Grayson ligaments:

• Grayson Ligament: Lies volar to the neurovascular bundle, passing from the tendon sheath to the skin. Elevated with the skin flap during exposure.
• Cleland Ligament: Courses dorsal to the neurovascular bundle from the phalanges to the skin, keeping the bundle pinned against the lateral side of the digit during flexion.
• Danger Point: In scarred revision fields, the neurovascular bundles are drawn medially by dense scar contracts, placing them directly across the midline of the flexor sheath where they are vulnerable to transection upon initial deep incision.

Surgical Approaches and Exposure Planes

• Brunner Zigzag Incision: Volar zigzag approach with 90-degree apex angles placed at the mid-axial line at each digital flexion crease. Provides direct, broad visualization of the flexor sheath and neurovascular bundles, while avoiding longitudinal linear scars that cause secondary flexion contractures. Flaps must be raised deep to the neurovascular bundles to preserve digital perfusion.
• Midaxial (Midlateral) Incision: Longitudinal incision placed along the neutral line of the digit (connecting the dorsal endpoints of the flexion creases when the finger is flexed). Passes dorsal to the digital neurovascular bundles, offering direct access to the lateral aspect of the flexor sheath and reducing volar skin breakdown.
• Dorsal Extensor Approaches: Longitudinal or lazy-S incisions over the dorsum of the wrist and hand. Dorsal sensory branches of the radial nerve (superficial branch) and dorsal cutaneous branch of the ulnar nerve must be identified and protected to avoid painful neuromas.

3. Pathogenesis

Tendon adhesion formation is the direct clinical manifestation of extrinsic fibroblastic dominance over intrinsic tenocyte proliferation during the normal reparative cascade following trauma or surgical repair.

Intrinsic versus Extrinsic Tendon Healing

Tendons heal through two competing biological processes:

• Intrinsic Healing: Driven by epitenon and endotenon tenocytes. When nurtured by synovial fluid and subjected to controlled passive motion, tenocytes synthesize organized, longitudinally aligned type I collagen fibers that restore tensile strength without anchoring to surrounding tissues.
• Extrinsic Healing: Initiated by the extravasation of inflammatory cytokines, fibroblasts, and capillary buds from the injured synovial sheath, surrounding subcutaneous tissue, and adjacent bone. Extrinsic fibroplasia generates a chaotic, random network of type III collagen that bridges the tendon epitenon to adjacent immobile structures, creating dense peritendinous adhesions.

Fracture Callus and Trauma-Induced Fibroplasia

Concomitant skeletal trauma represents the most potent inducer of dense adhesions. When proximal or middle phalangeal fractures occur, periosteal disruption and fracture hematoma invade the floor of the flexor or extensor tendon sheath. Extrinsic fibroblastic proliferation merges directly with the osteogenic callus, effectively cementing the flexor or extensor tendons to bone. Prominent internal fixation hardware, dorsal plate protrusion, or penetrating bicortical screw tips further provoke mechanical abrasion, foreign body inflammation, and dense scarring.

Excursion Mechanics and Biomechanical Deficits

Restoration of normal finger motion requires strict linear tendon excursion:

• Excursion Benchmarks: Complete digital composite flexion requires 30 to 40 mm of total FDP excursion at the wrist, 25 to 30 mm in the palm, and 5 to 9 mm of differential glide between FDS and FDP within Zone II. Extensor tendons require 12 to 16 mm of excursion across the wrist and 4 to 8 mm across the MCP joint.
• Biomechanical Consequences of Tethering: A fibrous adhesion tethering even 2 to 3 mm of tendon glide results in an active motion deficit of 30 to 50 degrees across the PIP and DIP joints.
• Quadriga Effect: Because the FDP tendons to the middle, ring, and small fingers originate from a shared proximal muscle belly, adhesion of one digit restricts proximal excursion of the entire muscle unit, causing secondary flexion lag in adjacent uninjured digits.
• Lumbrical Plus Phenomenon: If the FDP tendon is tethered or divided distal to the origin of the lumbrical muscle in the palm, forceful proximal contraction transmits tension through the lumbrical into the extensor hood, paradoxically extending the IP joints rather than flexing them.

4. Natural History

In the absence of surgical intervention, dense peritendinous adhesions remain mechanically permanent. Immature granulation tissue matures over 12 to 16 weeks into dense, hypocellular scar tissue dominated by cross-linked collagen bundles that do not remodel or elongate spontaneously.

If active tendon excursion is not re-established, the continuous absence of active motion leads to secondary capsular and ligamentous contractures. The volar plates of the PIP and DIP joints undergo adaptive shortening, collateral ligaments contract, and checkrein ligaments become fibrotic, converting a flexible active motion deficit into a rigid, fixed composite contracture. Chronic lack of excursion leads to disuse osteopenia, intrinsic muscle atrophy, and permanent loss of grip strength.

Epidemiologically, peritendinous adhesions represent the most common complication of flexor tendon repair. Adhesion-related active motion deficits develop in 10% to 25% of isolated primary flexor tendon repairs in Zone II. In complex crush injuries, contaminated wounds, or combined tendon-fracture injuries, the incidence of restrictive adhesions rises to 30% to 45%. The vast majority of affected patients are working-age individuals between 20 and 55 years of age, with a marked male predominance (70%) and frequent involvement of the dominant extremity.

5. Clinical Presentation

History

Patients present with persistent functional impairment following prior tendon repair, deep laceration, or surgical fixation of phalangeal or metacarpal fractures. Key historical features include:

• Motion Discrepancy: The hallmark symptom is the ability to passively curl or straighten the digit into a full fist or complete extension with external assistance, but an inability to achieve that same arc actively.
• Rehabilitation Plateau: A documented plateau in active motion progress for at least 4 to 6 weeks despite diligent participation in specialized hand therapy.
• Mechanical Symptoms: Catching, pulling sensations, or localized pain over the site of previous repair during resisted active flexion.
• Functional Impairment: Difficulty grasping small objects, impaired keyboarding, loss of cylindrical grip strength, or difficulty releasing grasped items.

Physical Exam

Physical examination must follow a disciplined, quantitative evaluation protocol comparing active range of motion (AROM) to passive range of motion (PROM) for each individual joint:

• Total Active Motion (TAM) Calculation: TAM = (Active Flexion: MCP + PIP + DIP) – (Active Extension Deficit: MCP + PIP + DIP). Normal composite TAM is 260 degrees.
• Total Passive Motion (TPM) Calculation: Measured identically to TAM using passive joint manipulation. When TPM exceeds TAM by greater than 30 to 40 degrees, extrinsic tendon adherence is confirmed, whereas equal deficits in both TPM and TAM indicate primary joint capsular contracture.
• Pulp-to-Palmar Crease (PPC) Distance: Measured in millimeters from the digital fingertip pulp to the distal palmar crease during maximum active composite flexion (normal = 0 mm).
• Isolated FDS Excursion: Evaluated by holding all adjacent digits in full passive extension (inactivating the common muscle belly of the FDP) and instructing the patient to actively flex the PIP joint. Absence of active PIP flexion indicates FDS rupture, denervation, or dense adhesion.
• Isolated FDP Excursion: Evaluated by stabilizing the PIP joint in full passive extension and asking the patient to actively flex the DIP joint. Inability to flex the DIP joint confirms FDP tethering or discontinuity.
• Tenodesis Maneuver: Passive wrist flexion normally drives digital extension, while passive wrist extension produces passive digital flexion. If wrist extension fails to induce digital flexion, the flexor tendons are either ruptured or tethered distally; if wrist extension causes sudden, rigid clawing, proximal adhesions tether the tendons to the carpus or forearm.
• Bunnell-Boyes Test (Intrinsic Tightness): Differentiates intrinsic muscle tightness from extrinsic extensor adhesions. Passive PIP flexion is assessed with the MCP joint held in extension, then repeated with the MCP held in flexion. If PIP flexion is restricted only when the MCP is extended, intrinsic tightness is present; if PIP flexion is equally restricted regardless of MCP position, extrinsic extensor adhesions or capsular contractures exist.

6. Imaging and Diagnostic Studies

Diagnostic imaging validates clinical findings, defines structural continuity, and identifies mechanical obstacles such as retained or prominent hardware:

• Plain Radiographs: Standard 3-view hand and dedicated digit radiographs (anteroposterior, true lateral, and oblique). Essential for assessing osseous union, residual phalangeal malunion, exuberant callus, heterotopic ossification, and prominent hardware (dorsal plate protrusion or bicortical screw tips penetrating the flexor sheath).
• Dynamic High-Resolution Ultrasonography (15 to 22 MHz): The imaging gold standard for suspected tendon adhesions. Allows real-time cine evaluation of tendon excursion during active muscle contraction and passive motion. Adhesions appear as hypoechoic or mixed-echogenicity peritendinous soft-tissue bands tethering the tendon to the sheath or bone, with characteristic absence of gliding and acoustic shadowing. Dynamic ultrasound reliably distinguishes partial tendon tears, complete ruptures, and intact tethered tendons.
• Magnetic Resonance Imaging (MRI): Reserved for ambiguous presentations, multi-tendon injuries, or suspected infection. High-resolution T1-weighted images show tendon morphology, while T2-weighted and proton density sequences demonstrate fluid halos, fibrotic bridging, and obliteration of the synovial space. Gadolinium administration assists in differentiating active inflammatory tenosynovitis from mature fibrotic scarring.

7. Classification

Validated classification and grading frameworks standardize functional outcomes and categorize anatomical adhesion patterns to guide operative release strategies:

8. Treatment

Medical / Nonoperative

Nonoperative management is the mandatory initial step following tendon repair or fracture fixation and must be exhausted before considering tenolysis:

• Specialized Hand Therapy Regimen: Supervised rehabilitation with a certified hand therapist utilizing dynamic splinting, static progressive orthoses, and relative motion flexion or extension splints to address soft-tissue tethers.
• Modalities and Scar Remodeling: Deep cross-friction scar massage, silicon gel sheeting, compressive Coban wrapping, therapeutic ultrasound, and active differential tendon gliding exercises (straight fist, hook fist, composite fist).
• Objective Failure Criteria: A minimum of 3 to 6 months elapsed since the index surgery or trauma, passive joint mobility that is supple and complete, and an objective lack of AROM progression documented over a consecutive 4- to 6-week observation period despite rigorous patient adherence.

Operative

The primary goal of tenolysis is the complete liberation of tendon excursion along its entire anatomical course while maintaining pulley integrity, vascular supply, and tendon continuity:

• Anesthetic Strategies: Wide-Awake Local Anesthesia No Tourniquet (WALANT) is the preferred approach. Infiltrating 1% lidocaine with 1:100,000 epinephrine into the planned incision sites eliminates tourniquet pain and enables intraoperative active movement testing. If general or regional anesthesia is employed, an auxiliary counter-incision in the distal forearm or palm is mandatory to perform a proximal traction maneuver.
• Surgical Technique (Flexor Tenolysis):
  • A Brunner zigzag or midaxial incision is created to expose the flexor sheath. Skin flaps are raised full-thickness, keeping the digital neurovascular bundles protected and retracted laterally.
  • The tendon sheath is inspected. A1, A3, and cruciform pulleys (C1 to C3) may be divided as needed. The A2 and A4 pulleys must be preserved, maintaining at least 50% of their axial width.
  • Sharp dissection using a Beaver blade or No. 15 blade held flat against the tendon surface is carried out to excise peritendinous scar tissue. The plane between the epitenon and peritendinous fibrosis is meticulously developed without breaching tendon substance.
  • Differential glide between FDS and FDP is re-established by splitting Camper chiasm adhesions. Adhesions binding the deep surface of the FDP to the phalangeal periosteum are lysed with curved tenolysis elevators.
  • The dorsal vincula are carefully visualized and preserved to safeguard intrinsic perfusion.
• Verification of Complete Excursion: Under WALANT, the patient is asked to actively make a full composite fist and extend completely. The fingertip pulp must touch the distal palmar crease (0 mm distance) without catching. Under general or regional anesthesia, traction on the proximal tendons through a forearm or palm incision must demonstrate effortless, full composite flexion of all digital joints.
• Concomitant Procedures: Concurrent hardware removal (plates, screws) should be executed if hardware abrades the tendon. If passive joint stiffness remains after complete tenolysis, a sequential palmar plate release, checkrein ligament excision, or collateral ligament release (capsulectomy) is performed.

Indications & Contraindications

Strict patient selection criteria separate successful functional restorations from catastrophic ruptures and recurrences:

• Indications:
  • Objective discrepancy between PROM and AROM, where PROM exceeds AROM by at least 30 to 40 degrees, or active pulp-to-palmar distance exceeds 1.5 cm.
  • Mature scar envelope with soft, pliable skin and resolved edema (minimum 3 to 6 months post-injury or repair).
  • Supple passive joint mobility (passive flexion within 10 to 15 degrees of normal).
  • Therapy plateau of at least 4 to 6 weeks.
  • Highly motivated, compliant patient committed to immediate postoperative therapy.
• Contraindications:
  • Rigid passive joint contractures (PROM equal to AROM) without prior therapy or a planned staged capsulectomy.
  • Immature scar tissue or active trophic inflammation (less than 3 months post-injury).
  • Severe structural tendon attenuation or fraying exceeding 50% of the tendon cross-sectional diameter (indicates staged tendon reconstruction with a silicone rod rather than tenolysis).
  • Complete loss of protective digital sensation or severe digital ischemia.
  • Unreliable, uncooperative patient unable to participate in immediate active rehabilitation.

9. Outcome

Modern clinical outcomes following digital tenolysis demonstrate significant functional restoration when strict selection benchmarks and immediate postoperative active motion protocols are applied:

• Total Active Motion (TAM) Recovery: Systematic reviews demonstrate a mean improvement in TAM of 45 to 65 degrees across all flexor zones. Good-to-excellent functional outcomes (Strickland criteria) are achieved in 65% to 75% of patients undergoing isolated digital flexor tenolysis. Extensor tenolysis outcomes are even higher, yielding 75% to 85% good-to-excellent results.
• Patient-Reported Outcome Measures (PROMs): Significant, durable reductions in Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores (mean improvement 24 to 32 points) and marked improvements in Michigan Hand Outcomes Questionnaire (MHQ) domains of hand function, activities of daily living, and pain relief. Grip strength recovers to an average of 75% to 85% of the contralateral uninjured side.
• Prognostic Determinants: Favorable outcomes correlate strongly with preoperative supple passive joint motion, isolated single-tendon involvement, patient age under 45 years, and early postoperative mobilization within 24 to 48 hours. Conversely, poor outcomes are linked to Zone II injuries with combined FDS/FDP scarring, multi-digit trauma, concomitant crush injury with fracture callus, and smoking.

10. Complications

Tenolysis is a technically unforgiving salvage procedure with a substantial complication profile that must be managed proactively:

11. Pearls and Pitfalls

• The Supple Joint Prerequisite: Never operate on a stiff passive joint. Tenolysis only restores active glide to a tendon; it cannot overcome capsular contractures or rigid collateral ligaments. If PROM is restricted, perform a pre-tenolysis rehabilitation protocol or prepare to execute a formal capsulectomy concurrently.
• Flat Blade Micro-Dissection: Maintain the scalpel blade flat against the tendon substance at all times. Shave scar tissue off the tendon surface parallel to the longitudinal collagen fibrils. Angling the blade inward notches the tendon, creating stress risers that precipitate catastrophic intraoperative or postoperative rupture.
• The 50% Pulley Rule: Never sacrifice more than 50% of the axial width of the A2 and A4 pulleys. If exposure is difficult, sacrifice the A1, A3, and C pulleys freely, but preserve the core integrity of A2 and A4 to prevent crippling bowstringing.
• Safeguard the Mesotenon: Avoid circumferential tendon stripping. Restrict tenolysis to the anterior and lateral surfaces of the tendon whenever possible, leaving the dorsal mesotenon and vincula intact to maintain essential intrinsic blood flow.
• The Attenuation Threshold: If more than 50% of the tendon cross-sectional diameter is frayed, degenerated, or structurally compromised during scar excision, abort tenolysis. Performing tenolysis on a severely attenuated tendon guarantees postoperative rupture; convert immediately to a staged silicone rod reconstruction.
• Tourniquet Deflation and Hemostasis: If a tourniquet is utilized, always deflate before final wound closure and achieve absolute hemostasis with bipolar cautery. A postoperative hematoma represents the ultimate biological substrate for rapid, dense fibroblastic proliferation and recurrent adhesion formation.
• Immediate Postoperative Motion: Active motion must begin within 24 to 48 hours. Construct a protective dorsal blocking splint that permits full active composite flexion while restricting extension to neutral, ensuring the patient exercises actively under the supervision of a certified hand therapist.

12. Controversy

WALANT versus General or Regional Anesthesia

The choice of anesthesia represents a major paradigm shift in modern hand surgery. Proponents of Wide-Awake Local Anesthesia No Tourniquet (WALANT) emphasize that real-time intraoperative active motion allows the surgeon to confirm complete excursion, detect subtle residual adhesions within Camper chiasm, and demonstrate to the awake patient their achievable range of motion, providing psychological reassurance that facilitates postoperative compliance. Conversely, critics argue that patient anxiety, localized pain during deep scar release off periosteum, and epinephrine-induced vasospasm can complicate long, intricate revision cases. In patients requiring extensive multi-digit tenolysis or concurrent osteotomies, regional axillary block or general anesthesia paired with an objective proximal traction maneuver remains widely utilized.

Optimal Timing: 3 Months versus 6 Months Post-Injury

Determining the ideal interval between primary repair and tenolysis remains intensely debated. Early advocates recommend waiting at least 6 months to guarantee full biological scar maturation, complete resolution of tissue edema, and maximum passive joint supple recovery. However, contemporary proponents of earlier intervention (3 to 4 months) argue that waiting 6 months allows secondary capsular contractures, joint stiffness, and disuse muscle atrophy to progress, making subsequent tenolysis technically more difficult and less rewarding. Current consensus supports early intervention at 3 to 4 months only if passive motion is completely supple, soft tissues are quiescent, and therapy has objectively plateaued for 4 to 6 weeks.

Concurrent versus Staged Pulley Reconstruction

When the A2 or A4 pulley is attenuated, scarred, or inadvertently breached during tenolysis, controversy exists regarding concurrent reconstruction versus staged management. Performing concurrent pulley reconstruction using a tendon graft or retinacular sling restores mechanical advantage but introduces fresh suture lines that require initial immobilization, directly conflicting with the core principle of immediate postoperative active motion for tenolysis. Most authors advocate preserving whatever functional pulley tissue remains or performing minimal venting; if formal pulley reconstruction is unavoidable, a staged approach with a silicone spacer is preferred to prevent simultaneous re-adhesion of the reconstructed pulley to the lysed tendon.

Pharmacologic and Biological Adhesion Barriers

Extensive research has investigated adjuvant agents to inhibit extrinsic fibroplasia without impairing intrinsic tendon healing. Evaluated modalities include local intraoperative 5-fluorouracil (5-FU) irrigation, cross-linked hyaluronic acid gels, steroid instillations, and bioresorbable polymer membranes (e.g., collagen sheets, polyethylene glycol wraps). While animal and small clinical trials report modest reductions in adhesion density, routine clinical use remains controversial due to conflicting evidence, risks of impaired wound healing, increased infection rates, and potential weakening of tendon structural integrity.

13. Evidence-Based Synthesis

Modern clinical decision-making is grounded in high-quality randomized controlled trials and prospective registry analyses, corroborated by seminal biomechanical and anatomical descriptions.

14. References

• VAN Carlen M, Plonczak A, VAN J et al. A Systematic Review of the Outcomes of Flexor Tenolysis in Zones 2-5. J Hand Surg Asian Pac Vol. 2022. doi:10.1142/S2424835522500576 [Level I (Therapeutic): Systematic Review / Meta-Analysis]
• Kher S, Graham DJ, Symes M et al. Outcomes of Isolated Digital Flexor Tenolysis: A Systematic Review. J Hand Surg Asian Pac Vol. 2021. doi:10.1142/S2424835521500557 [Level I (Therapeutic): Systematic Review / Meta-Analysis]
• DE Vries BCJM, VAN Dongen JA, VAN DER Heijden EPAB. Tenolysis after Operative Treatment of Hand Fractures: A Systematic Review. J Hand Surg Asian Pac Vol. 2026. doi:10.1142/S2424835526500256 [Level I (Therapeutic): Systematic Review / Meta-Analysis]
• Whitaker JH, Strickland JW, Ellis RK. The role of flexor tenolysis in the palm and digits. J Hand Surg Am. 1977. doi:10.1016/s0363-5023(77)80028-2 [Level IV (Therapeutic): Clinical Case Series / Cohort Study]
• Fetrow KO. Tenolysis in the hand and wrist. A clinical evaluation of two hundred and twenty flexor and extensor tenolyses. J Bone Joint Surg Am. 1967. doi:PMID:6026002 [Level IV (Therapeutic): Clinical Case Series / Cohort Study]

15. Master Class Pro-Tip

The most decisive intraoperative moment during flexor tenolysis is the verification of complete differential excursion before skin closure. Under WALANT anesthesia, have the patient actively curl the digit into a tight fist; do not accept surgery as complete until the fingertip pulp effortlessly touches the distal palmar crease (0 mm distance) and full active extension is achieved without catching. If regional or general anesthesia is utilized, never rely on passive manipulation or manual traction across the palm. Make a formal 2-cm longitudinal incision in the distal forearm over the FDS and FDP muscle-tendon junctions. Pass a soft, moist silicone vessel loop around the isolated tendons and apply gentle proximal traction. The digit must smoothly curl into a full composite fist with the fingertip touching the palmar crease. If the PIP joint flexes but the DIP joint lags behind, dense scar tissue still bridges the FDP within Camper chiasm over the proximal phalanx; return to Zone II and lyse the tether before closing. Achieving complete passive-to-active excursion matching on the table is the only reliable predictor of long-term functional recovery.

Master Class Surgical Pearl: Intraoperative Verification of Flexor Excursion