• Tricky Tests:
• Elson’s test: with flexion of PIP –> DIP will extend due to central slip injury –> volar subluxation of lateral bands –> tight and DIP extension
• Typically negative due to lateral band laxity
• Quadriga effect: results as excess distal pull on one profundus (share common muscle belly), one pull decreases pull on others can occur secondary to amputations or fusion at PIP (index finger tolerated better than others)
• Lumbrical plus deformity: division of distal tendon results in proximal migration exacerbation tension on lateral bands (paradoxical extension of PIP at attempted flexion)–> treatment includes division of lumbrical tendon, resection, or division of lateral band (where it attaches)
• Extrinsic tightness would be noted in cases where MCP flexion limits PIP flexion. Intrinsic tightness would be noted if the patient was found to have inability to flex the PIP joint with MCP extension
• Extensor Anatomy: extrinsic tendons provide digital extension to all three joints; intrinsics flex MCP and extend Ips
• Zones (start at DIP I, VII is ER)
• Extensor tendon repairs worse in zone III and VI
• Juncturae tendinum are tendon like bands that connect long, ring and little finger extensor digitorum communis tendons  (if long finger lacerated proximal, the others will apply extensor force)
• Sagittal bands: aid with extension at MCP
• Sagittal band rupture or extensor tendon injury–> Relative motion extension splint keeps tendon at 15-20 degrees more extension than the other fingers
• Wrist component first with finger component x3 weeks followed by finger component only

• Extension at PIP from extrinsic (attachment through central slip) and intrinsic tendons through lateral bands (just proximal to central slip)
• Extension at DIP is produced by both extrinsic (though direct attachment of terminal tendon) and intrinsics (by the conjoined lateral bands proximal to DIP)
• Extension of MCP by pull of EDC (and EIP/EDQ) and its attachment to the sagittal bands

the intrinsic extensor mechanism, via the middle band of the interosseous muscles, also inserts on the dorsal base of the middle phalanx and causes extension of the PIP joint. In an open injury, the central slip may be injured without concurrent injury to the interosseous muscle tendon, allowing the patient to still actively extend the PIP joint even in the presence of a disruption of the central slip.

• The oblique retinacular ligament connects the flexor tendon sheath volarly to the terminal extensor tendon dorsally. When a patient sustains a laceration to the extensor mechanism over the body of the middle phalanx bone, the oblique retinacular ligament may prevent the occurrence of an extensor lag and a mallet deformity
• Boutonniere Deformity: flexion at the PIP and hyperextension of DIP (called buttonhole deformity)
• Results from loss of extensor force at PIP with palmar migration of conjoined lateral bands secondary to triangular ligament insufficiency
• Central slip injury from laceration, avulsion (direct blow to an outstretched digit), attrition from chronic inflammation (RA), burns etc –> results in flexed position by unopposed flexor force –> palmar migration of lateral conjoined band –> concentrated extensor force at DIP –> may result to fixed deformity
• Presentation: usually main complaint is hyperextension DIP, can develop arthrosis of PIP

• Elson’s test: with flexion of PIP –> DIP will extend due to central slip injury –> volar subluxation of lateral bands –> tight and DIP extension
• Typically negative due to lateral band laxity
• Treatment:
• Conservative: hand therapy and corrective orthosis to obtain full PROM
• Splint PIP in extension and leave DIP free for 6-8 weeks–> should initiate range DIP exercises 
• Operative: relocate lateral bands dorsal
• Fowler procedure: surgical lengthening of the terminal tendon (for DIP)
• Dorsal repositioning of subluxated lateral tendons, repair/tightening of central slip (Littler)
• PIP contracture release involves releasing volar plate (done at separate stage at least 3 months apart)
• If there is arthrosis –> arthrodesis or arthroplasty
• Complications: incomplete correction, recurrence, overcorrection of DIP, stiffness, chronic pain etc
• Classification:
• Acute: acute central slip injury –> typically treated nonoperatively unless in the rare case of bony central slip injury (can treat with cerclage wire)
• Subacute: loss of active extension and passive extension restriction –> attempt with conservative management first –> splinting or serial casting until supple passively correctable joint followed by operative management
• Chronic: prior to reconstruction –> need passive mobility and soft tissues
• Chronic and stiff –>  can consider capsular release (or digit widget!) –> 3 months to wait and then tendon reconstruction
• Swan Neck Deformity: flexion at DIP and hyperextension at PIP (loss of extrinsic force on distal phalanx or from over pull of extensor mechanism at PIP
• Consider whether it is flexible/passively correctible
• Etiology: loss of extension at DIP or over pull of extension force at PIP (IE loss of terminal tendon like a mallet finger, crush injuries of DIP)
• Laceration, closed avulsion from blow with outstretched digit, attritional (RA)
• Increased pull at central slip (RA or spasticity, intrinsic tightness)
• Bunnell intrinsic tightness test: flex PIP with MCP flexed or extended –> if PIPJ tighter with MCP extended–> intrinsic tightness
• Volar subluxation of MCP joints like RA can lead to increased pull of central slip
• Loss of pull of FDS (laceration rupture etc)
• Laxity of volar plate –> stretch and rupture with time
• Over time deformity can become fixed and arthrosis develop
• Clinical Presentation: inability to flex PIP, can become locked in hyperextension –> with need for manual flexion, weak grasp, pain from arthrosis
• Physical Exam: check active and PROM, check if it is passively correctable
• Treatment: 
• Conservative: hand therapy, corrective arthrosis, try to obtain passive correctability
• Extension block orthosis helps correct PIP hyperextension
• Progressive extension orthosis for DIP
• Operative: 
• PIP: lengthening central slip, release intrinsics (if tight), FDS tenodesis (tightening PIP), dermodesis
• Fowler central slip tenotomy: central slip inserts on base of middle phalanx and acts on PIP joint–> helps rebalance extensor mechanism so terminal tendon can extend DIP with chronic mallet finger
• Tension on lateral bands also extends DIP
• Involves tenotomy of central slip and lateral bands
• oblique retinacular ligament can be used to correct swan neck deformity
• Arthrodesis or arthroplasty for arthrosis
• Correct any MCP subluxation with MCP arthroplasty
• Complications: incomplete correction, recurrence, stiffness, flexion contracture, chronic pain
• Planning tendon transfers:
• What works
• Whats available
• Whats needed –> functions not muscles
• Must retain one wrist flexor
• Matching- similar capacity, amplitude, and direction
• Staging
• Determining tendon junction sites and proper tension most important part of the surgery
• Junction sites: dorsum is either proximal or distal to extensor retinaculum (preserve this to prevent bowstringing)
• Tension –> too tight better than too loose –> when too loose only remedy is another operation (too tight can correct post-op with dynamic flexion for extensor transfers, an dynamic extension splint for flexor transfers)
• Pulvertraft weave- at least 2 and at 90 degrees to each other
• Types of Transfers: Direct tendon repair after 6 months with tendon graft not possible due to fibrosis and shortening of muscle belly
• High radial nerve palsy with no return of function in 6 months (seen intact at surgery)- tendon transfers

Brand Tendon Transfers:

• Wrist Extension –> PT to ECRB (3) (not both ECRB/ECRL)-
• Thumb Extension:

• PL or to-EPL or 

• FDS to EPL or 
• FCU/FCR can be used for both thumb and finger extension
• Digital extension –> FCR or FCU -EDC- done before wrist extension transfers (for tenodesis) –> tension set at MPs 20-30 degrees of flexion (also FDS)

Disadvantage of using FCU is loss of important wrist stabilizers, inadequate excursion

• Cascade tends to have more tension on index rather than small –> make sure to tension equally
• FCR can be used to APL –> extends first metacarpal NOT abducts
• Can use FDS for finger extension

• AIN Palsy-

• Examination: will reveal paralysis of FPL, FDP index and PQ –> evaluate PQ with resisted pronation and elbow in full flexion
• FDP to FDP: side to side –> remove paratenon, or can do end to end and weave (more complicated)
• FDS (ring) –> FPL: ideal transfer as they have similar forces excursions etc
• EPL rupture: EIP –> EPL
• Leave EIP in 4th compartment, ideal transfer (close and similar direction etc)
• Rheumatoid Arthritis: 
• Small finger
• Small and ring
• Small ring and long: options include 
• FDS  can be through IO, around ulnar border of forearm, around radial border (preferred because it will not contribute to ulnar deviation in rheumatoid patients)
• Volkmann’s ischemic contracture: finger contractures
• Fibrosis typically of FDP muscles –> can do end to side FDP to those what is working
• Chronic FPL laceration: IP fusion versus FDS ring finger (due to chronic FPL contracture)
• FDS ring –> sufficient length when divided in the distal palm –> suture to bone in distal phalanx
• Mid axial incision –> ensure FPL has poor excursion –> FDS ring to FPL
• Intrinsic Tendon transfers: 
• Thumb (flexion/extension/abduction/adduction)

• If EIP to EPL for chronic rupture –> do not need to reroute 

• Oppensplasties: APB most important thenar muscle (seek to restore flexion, abduction and pronation of the thumb)
• Median nerve injuries do not usually require opponensplasties as FPB while weak can achieve abduction
• Phalen ECU à EPB around ulna
• Burkhalter EIPà APB around ulna sub q

• Most common
• Rerouted from dorsal of hand to volar aspect of palm and sutured in to AbPB
• Michelanikis FDS (4^th) à APB
• Attach to thumb –> dorsal ulnar side of the proximal phalanx*** OR APB tendon OR APB and EPL
• Camitz (passive) palmaris plus fascia –> APB
• Main indication with severe carpal tunnel and no thenar abduction (perform in concert with nerve decompression)
• ADQ (Huber) –> incise along border of hypothenar eminence–> ADQ dissected –> detach muscle from pisiform –> identify neurovascular bundle and protect –> rotate ADQ 180 degrees (like turning a page of a book) –> attach to tendon of APB
• Low ulnar nerve palsies –> bouvier test –> intrinsic repositioning
• FDS to A2 pulley passive transfer for intrinsic repositioning
• FDS transfer to the lateral band (of both the ring and little fingers) will correct the loss of interphalangeal joint extension described (wartenburg sign), can use EDL if in need of all fingers (anticlawing)
• Intrinsic tightness test: extension of PIP joints with attempts at mp extension
• Tendon Injury
• Acute Flexor Tendon Injuries
• Zones: The flexor tendon system of the hand is divided into five zones 
• Zone I is the area distal to the flexor digitorum superficialis (FDS) insertion at the mid-middle phalanx. (only contains FDP)
• Zone II area from the FDS insertion at mid-middle phalanx proximally to the A1 pulley at approximately the level of the distal palmar crease (proximal portion of digital sheath
• Zone III area between the proximal aspect of the A1 pulley and the proximal aspect of the origin of the lumbrical muscles from the FDP tendons (distal portion of TCL to distal palmar crease)
• Zone IV  region within the carpal tunnel.
• Zone V from the musculotendinous junction distally to the proximal edge of the TCL.
• Flexor Digitorum Superficialis: 
• flexes PIP
• innervated by median nerve 
• Flexor Digitorum Profundus
• flex the distal interphalangeal (DIP) and the PIP joints.
• Innervated by median nerve (index and long finger); and ulnar nerve (ring and small)
• The FDS slips insert on the mid-middle phalanx, while the FDP continues through

the fibro-osseous sheath to insert on the volar base of the distal phalanx.

• Digits have fibro-osseous sheaths lined with synovium (both FDS/FDP travel through here

• 5 annular pulleys, 3 cruciform pulleys (numbered proximal to distal)(keep tendon apposed to bone)
• Order: A1 (MCP) –> A2 (periosteum of proximal phalanx) –> C1 –> A3 palmar plate of PIP –> C2 –> A4 (periosteum of middle phalanx) –> C3 –> A5 (palmar plate of DIP)
• FDS is superficial to FDP at entrance into digital sheath –> FDS then divides into two slips that wrap around FDP and become more dorsal –> two slips then rejoin via fibers of campers chiasma
• A2 can rupture in rock climbers or gymnasts –> treat with supportive measures and ring splint
• Examination (examine prior to local anesthetic), use cap refill and 2 point for NV exam

• Location of laceration, resting posture of hand and digits (will be extended if flexor tendon laceration
• Test FDS by examining isolated PIP flexion of each digit with other digits held in full extension at MCP/PIP/DIP
• FDP test by asking patient to flex DIP joint while PIP held in extension
• Tenodesis: flexion of the wrist will extend the fingers (in intact tendons) and extension of the wrist will flex the fingers
• TARM: added MCP, PIP, DIP – extensor lag (270 normal)
• Treatment:
• Knots: strength is increased by higher suture caliber, stiffer materials, more core strands; epitendinous sutures improves biomechanical strength, minimizes gapping, and helps reduce cross-sectional area for gapping
• Knot location: should be an outside knot (some do inside but strength is less initially)
• Most biomechanical strength is a 3-0, locking suture repair with a dorsally placed 
• 4 strand core suture and 1cm from cut end, epitendinous suture 2mm deep and 2mm back from cut edge–>Most common core stitch is cruciate- locking has been shown to be superior
• Tapered needle preferred
• Zone I: (isolated FDP Injuries, or avulsion injuries)
• Jersey finger-avulsion of the tendon from the distal phalanx or a fracture of the base of the distal phalanx 
• Classically the ring finger is involved, and the mechanism of injury is a sudden hyperextension moment applied to a finger with the FDP in maximal contraction
• Leddy classification:
• Type I: The proximal tendon is retracted into the palm. Disruption of the vinicular blood supply (early repair important)
• Type II: The tendon is retracted to the PIP joint
• Type III: Avulsion of the tendon with a bony fragment. The bony fragment usually is entrapped by the distal edge of the A4 pulley, which prevents retraction
• Suture Buttons
• May also use suture anchors or pins/screws if bony avulsion
• Zone II
• Known as no mans land due to historically poor results
• Repair if  >60% of the tendon cross-sectional area is disrupted. If <60% of the tendon is disrupted –> then debride cut edges to prevent tendon catching at the pulleys.
• Epitendinous sutures decrease gap formation, improve contour, and improve strength of the construct between 10% and 40% of ultimate tensile strength –> use 5-0 or 6-0 running prolene
• Zone III: usually complex injuries due to proximity of NV structures (common digital, superficial arch, motor branch of median and lumbrical muscles)
• Remember too much advancement causes lumbrical plus finger (paradoxical IP extension with attempted forceful flexion
• Zone IV: rare because of protection provided by the TCL and carpal bones –> injuries in this zone involve the median nerve as it is most superficial structure in the carpal tunnel
• At least 4 strand core repair
• Zone V: can be repaired within 3 weeks –> after this MSK unit shortens and has to be reconstructed or undergo tendon transfers
• Tendon-tendon repair– using 3-0 braided suture, 4 strand core stitch and 5-0 epitendinous (not as important)
• MSK repair– interrupted 3-0 permanent kessler or figure of 8 with a running nylon epitendinous suture
• Intramuscular:  horizontal mattress stitches with 0 and 2-0 absorbable suture placed through fascia to approximate ends
• Flexor tendons in zone 5 have best prognosis for repair (proximal to carpal tunnel)
• Flexor Tendon Rehabilitation Principles: Zone II outcomes still marginal and often require tenolysis and joint capsular release, ruptures occur in up to 6% of repairs

• 6 weeks –> tendon repair 20% stronger than surgery
• Flexor Tendon Rehabilitation Programs:

• Passive ROM (Duran Protocol): passive exercises under therapists supervision; post operative orthosis includes extension block with IP extended, 
• Kleinert Modification of Passive Motion Protocol:
• Elastic bands are attached to the digit’s nail and pass under a palmar hand pulley to the wrist
• Active Motion Protocols: all controlled motion protocols designed to provide excursion without gap formation (unlike passive which depends on externally applied forces to produce tendon gliding and adhesion prevention)
• Early Active Motion:  
• Best for ROM, higher rate of ruptures. Need at least four strands to initiate
• Low force and moderate excursion therapy best protocol following flexor tendon; early active motion may limit end softening and loss of repair strength that occurs after first 7 days
• Increased excursion
• For tendon grafting repairs in children, complete immobilization for 4 weeks
• Do not perform tenolysis until 4-6 months out from tendon repair, hand therapy first line treatment
• Boyes Preoperative Classification:
• 
• The Boyes Preoperative Classification scheme can be used as a tool to assess the need for either a one- or two-stage repair. The indications for a one-stage repair include a properly healed wound, full passive range of motion, absence of significant scarring, an intact pulley system and tendon sheath, preserved neurovascular function, and absence of PIP joint flexion contracture upon initial wound exploration (Boyes grade 1;If these conditions are not satisfied (Boyes grade 2–5), patients are generally better candidates for two-stage reconstruction.
• Rupture of repaired tendon: most common 4-6 weeks out, explore and repair; staged reconstruction used for tendon rupture if passive range of motion limited or no sheath
• MRI best diagnoses rupture; early ruptures (days to weeks) can be treated with repair of both; transfers/grafting secondary procedures
• Stage 1: pulley reconstruction overs silicone rod (A2/A4 critical)
• Stage 2: tendon grafting
• Choice of donor tendon: PL (extrasynovial, most common-good for distal finger to mid palm, minimal donor morbitidity); plantaris (extrasynovial, requires leg dissection); toe extensors (extrasynovial, requires leg dissection); flexor digitorum longus (intrasynovial, usually second toe)

• Palmaris longus is readily accessible and available in 85% of patients, has little morbidity, appropriate size for most fingers
• Intrasynovial has less scaring and adhesions, but has length issues
• Extrasynovial is easier to harvest, pre-operative US good to determine if plantaris is intact and its location
• Tendinitis

Anatomy: six dorsal compartments

• APL, EPB – De Quervain’s Syndrome
• ERCL, ECRB – Intersection Syndrome
• EPL – Chronic rupture in non-displaced distal radius fractures
• EIP (most distal extensor muscle belly), EDC – Mid-dorsal wrist pain in piano players
• EDM – Vaughn Jackson Syndrome
• ECU – Snapping ECU Syndrome
• First dorsal compartment

• Contains APL and EPB which run through a rigid tunnel
• Base of tunnel is formed by a groove in the radial styloid whereas roof to tunnel is formed by extensor retinaculum
• APL – larger, has multiple slips; EPB – smaller, more dorsal, more distal muscle belly and often contained within own subcompartment (frequent cause of dequervain’s)
• Clinical Evaluation
• History includes handedness, occupation, mechanism
• Present with radial sided wrist pain that is exacerbated by lifting or grabbing
• Tenderness over first dorsal compartment–> near radial styloid
• Intersection syndrome –> 5cm proximal to wrist joint
• Physical Exam:
• Eichoff: patient grasps thumb inside clenched fist and ulnarly deviates the wrist
• Finklestein: examiner grasps patients thumb and deviates wrist ulnarly
• Treatment:
• Non-operative- first line: includes rest, NSAIDs, CSI, removable thumb spica
• CSI: effective option in 50-80% of patients (less effective in diabetes)
• Operative management: indicated when conservative management fails (generally offer 1 CSI and then if symptoms are still present 4-6 months later offer surgery)
• Lateral epicondylitis: sharp pain at epicondyle exacerbated by passive flexion of wrist and fingers with elbow extension (corticosteroid injection), typically ECRB
• ECRB is implicated in the development of lateral epicondylitis 
• Intersection syndrome: pain syndrome in distal forearm at intersection of first and second extensor compartment (APL/EPB), ECRL/ECRB, pain proximal to lister’s tubercle, corticosteroids or tenosyovectomy, pain on repetitive motions in wrist, initial is non op with rest, NSAIDS and splinting in extension 15 degrees –> if doesn’t work surgical release of second compartment
• Intersection syndrome: tenosynovitis of second dorsal compartment ERCL/ERCB near first extensor compartment, pain 4cm proximal to wrist with erythema and crepitus, from prolonged wrist motion (may release second dorsal compartment)
• De quervain: first compartment presents with wrist pain on radial side aggravated by movement of the thumb; finklestein test: clasped thumb in palm while wrist is ulnarly deviated, splint in extension with thumb abducted, then surgical release
• Third compartment:
• EPL controls hyperextension of the IP joint of the thumb, intrinsics IP to neutral
• tenosynovitis is pain at lister’s tubercle, urgent surgical release
• EPL- can be ruptured in nondisplaced or minimally displaced distal radius fractures –> treatment with EIP tendon transfer
• Cannot lift thumb off of the table
• Stenosing tenosynovitis (trigger finger)
• Congenital trigger thumb: intermittent episodes of catching or locking thumb since birth, cannot passively extend with palpable nodule of FPL –> release of A1 pulley, caused by proliferation of synovial fluid  (nottas node- do not excise)
• Injection
• Moment arm: perpendicular line from mid axis of joint to tendon causing movement in joint (increases with pulley rupture), movement will decrease, power increases (with loss of efficiency)
• Miscellaneous
• UCL/RCL injuries
• Angulation on lateral stress >20 degrees on finger is associated with poor prognosis in collateral ligament injury, partial tears can be treated conservatively with buddy taping or extension block placement
• UCL– <30 degrees or 15 degrees when compared to other side can be treated with immobilization with thumb spica; operative repair for greater; stener lesions result after full tears
• RCL injuries: forced ulnar deviation at MCP, pinch results in pain and ulnar deviation –> need MRI –>
• RCL ligament injury of PIP –> > 20 degrees laxity is poor prognosis and indicates repair
• 2 hours upper limit of ischemia time, 5 minutes release for every 30 minutes use
• Remember for PIP contractures (surgical release) –> release cheikrein ligaments first, followed by accessory collateral and manipulation
• Congenital clasp thumb is absence of EPL or EPB with abduction and flexion
• FDS to FDP for spastic clenched fist deformity
• FPL courses through scaphoid, can rupture as a result of scaphoid fractures
• Severely contaminated wounds should be irrigated and debrided –> fractures/skin loss treated in primary procedure, tendons must be repaired in 7 days –> can use ALT, thoracodorsal etc