05 hand tendon

tendon injuries hand, Yasha-Vardhan tendon injury, tendon injury Orthopaedics

1. Department of O rthopaedics Seminar on: Flexors & extensor tendon injuries of hand. Chairperson and moderator: Prof. & HOD: Dr. Kiran Kalaiah Presenter : Dr. Yashavardhan.T.M

2. Introduction. Tendon injuries are the second most common injuries of the hand and therefore an important topic in trauma and orthopaedic patients. “A glistening structure between muscle & bone which transmit force from muscle to the bone’” Paratenon : Loose areolar tissue encasing tendon in low mechanical stress area Tendon sheath: a dense fibrous tissue tunnel enclosing tendon in high mechanical stress area 70% collagen (Type I) Extracellular components • Elastin • Muco -polysaccharides (enhance water-binding capability)  Endotenon – around collagen bundles  Epitenon – covers surface of tendon  Paratenon – visceral/parietal adventitia surrounding tendons in hand

3. Most injuries are open injuries to the flexor or extensor tendons, but less frequent injuries, e.g., damage to the functional system tendon sheath and pulley or dull avulsions, also need to be considered. After clinical examination, ultrasound and magnetic resonance imaging have proved to be important diagnostic tools. Tendon injuries mostly require surgical repair, dull avulsions of the distal phalanges extensor tendon can receive conservative therapy.

4. Injuries of the flexor tendon sheath or single pulley injuries are treated conservatively and multiple pulley injuries receive surgical repair. In the postoperative course of flexor tendon injuries, the principle of early passive movement is important to trigger an "intrinsic" tendon healing to guarantee a good outcome. Many substances were evaluated to see if they improved tendon healing; however, little evidence was found. Nevertheless, hyaluronic acid may improve intrinsic tendon healing

5. Anatomical position Flexors muscles : FDP and FDS tendons have fibrous sheaths on the palmar aspect of the digits Fibrous arches and cruciate (cross-shaped) ligaments, which are attached posteriorly to the margins of the phalanges and to the palmar ligaments hold the tendons to the bony plane and prevent the tendons from bowing when the digits are flexed. The tendons are surrounded by a synovial sheath. Flexor tendon system consists of intrinsic and extrinsic components Extrinsics : FDP: flexing the DIP joint FDS: Flexing the PIP Joint FPL: Flexing the IP joint of the thumb Intrinsics : Lumbricals : Flex the MCP joints and Extend the IP joints FDP inserts on base of distal phalanx FDS inserts on sides of middle phalanx FPL inserts on proximal portion of the distal phalanx

6. INTEROSSEIUS, BLOOD SUPPLY & NERVE SUPPLY

7. Pulleys of flexour Synovial sheath is reinforced by a system of fibrous pulleys 5 annular pulleys (A) and 3 Cruciform pulleys (C) A1: 8-10 mm over MCPJ A2: 18-20mm over proximal phalanx A3: 2-4 mm over PIPJ A4: 10-12mm over middle phalanx A5: 2-4 mm over DIPJ C1, C2, C3 proximal to A3, A4, A5 Allow shortening of the pulley system in flexion A2 and A4 are considered most important. Their disruption leads to bowstringing, reduced mechanical efficiency and decreased flexion. Function: increase the mechanical efficiency by preventing bowstringing

8. ZONES OF FLEXOR TENDON INJURY Zone I: Between insertion of FDP and FDS Zone II: From insertion of FDS to A1 Pulley Zone III: Between A1 pulley and distal limit of carpal tunnel Zone IV: Within the carpal tunnel Zone V: Between the entrance of Carpal tunnel and musculo-tendinous junction. FDS decussation at A1 pulley FDS slips rotate 180° around FDP Slips rejoin at PIP – Camper’s Chiasma Insert on P2

9. Tendon nutrition Parietal paratenon Passive nutrition by diffusion Vincula and bony attachments Direct nutrition Segmental nutrition Vincula may prevent retraction Vascularity dominance is deep surface of tendon Consider with suture placement Biomechanically superior to place suture deep

10. TENDON HEALING Tendons are capable of actively participating in the repair process through Intrinsic Healing Tendon healing occurs in three phases: 1. Inflammation 2. Active repair 3. Remodelling • Early tendon motion has significant role in modifying the repair response • Mobilized tendons showed progressively greater ultimate load compared with immobilized tendons • Studies confirm “Wolff’s law” which states that the strength of a healing tendon is proportional to the controlled stress applied to it

11. ETIOLOGY  sharp object direct laceration (broken glass, kitchen knives or table saws)  crush injury  avulsions  burns  animal or human bites  suicide attempts  motor vehicle accidents

12. ZONE 1: ZONE OF FDP AVULSION INJURIES  Region b/w middle aspects of middle phalanx to finger tips  Contains only one tendon- fdp  Tendon laceration occurs close to its insertion  Tendon to bone repair is required than tendon repair Leddy classification of zone I flexor tendon injuries Type I: tendon retracted into palm (fullness in palm) Type II: tendon trapped in the sheath at PIP (unable to flex PIP) Type III: tendon trapped in A4 pully

13. ZONE II-NO MANS LAND  From metacarpal head to middle phalanx  Called so because initial attempts for tendon repair here produced poor results  FDS and FDP within one sheath  Adhesion formation risk is amplified at campers chiasma In each finger, the FDS tendon enters the A1 pulley and divides into two equal halves that rotate laterally and then dorsally. The two slips rejoin deep to the FDP tendon over the distal aspect of the proximal phalanx and the palmar plate of the PIP joint at Camper's chiasma Insert as two separate slips on the volar aspect of the middle phalanx.

14. ZONE III-DISTAL PALMAR CREASE  B/w transverse carpal ligament and proximal margin of tendon sheath formation  Lumbricals origin here prevents profundus tendons from over acting  Delayed tendon repairs are succesfull even after several weeks of injury

15. ZONE IV-TRANSVERSE CARPAL LIGAMENT Lies deep to deep transverse ligament. Tendon injuries are rare . FPL and FDM enters its continuous sheath which becomes the radial and ulnar bursae . The FDS and the FDP also enter a large sheath and lie in the carpal tunnell

16. ZONE V LIES PROXIMAL TO TRANSVERSE CARPAL LIGAMENT The Flexor tendons start in the distal third of the forearm at the musculotendinous junction The superficialis group lies palmar to the conjoined profundus tendon group covered by loose subcutaneous tissue and skin.

17. SIGNS & SYMPTOMS  Unable to bend one or more finger joints  Pain when bending finger/s  Open injury to hand (e.g., cut on palm side of hand, particularly in area where skin folds as fingers bend)  Mild swelling over joint closest to fingertip  Tenderness along effected finger/s on palm side of hand  Lies deep to deep transverse ligament Tendon injuries are rare

18. EXAMINATION:  INSPECTION There is a normal arcade to hand with index finger showing least and little finger showing max flexion If affected finger shows more extension than other digits, chance of tendon injuries are high

19. Goals of reconstruction  Coaptation of tendons  anatomical repair  multiple strand repair to permit active range of motion rehabilitation  Pully reconstruction to minimize bow-stringing  atraumatic surgical technique to minimize adhesions  strict adherence to rehabilitation protocol.

20. Timing of flexor tendon repair: Primary : repair within 24 hours (contraindicated in case of high grade contamination i.e. human bites, infection) Delayed Primary : 1-10 days when the wound can be still pulled open without incision Early Secondary : 2-4 weeks. Late Secondary : after 4 weeks No repair if less than <25% laceration, only epitenon repair in 25-50% lacerations, core suture plus epitenon repair when >50% laceration Dorsal blocking splint for 6-8 weeks as conservative measure

21. Ideal tendon repair: Easy placement of sutures in the tendon Secure suture knots Smooth junction of tendon ends without gapping Minimal interference with vascularity strength

22. TECHNIQUES Retrieve the tendon ends through the sheath in an atraumatic manner Maintain the integrity of the pulley system (especially A2 and A4 ) Create “ retinacular window” described by Lister for preserving the flexor sheath Extend the original laceration for better exposure Zigzag Mid-lateral Avoid linear scars that cross flexion crease

23. Milk the forearm with the wrist and MCP in flexion Do not attempt blind retrieval more than twice Make a separate incision if necessary Use a pediatric feeding tube to retrieve tendon stump

24. CORE SUTURE

25. Six Strand Technique

26. Tendon Sheath Repair? Role of diffusion of nutrients from synovial fluid Tendon within the sheath have an intrinsic capacity for healing Gelberman and woo in 1990 study on dogs Reconstruction of the sheath did not significantly improve repaired tendons treated with early motion rehabilitation.

27. Partial Tendon Laceration Rupture, entrapment, triggering Partial laceration involving 60% or less are best treated by early mobilization WITHOUT tenorrhaphy

28. Profundus Tendon Avulsion Avulsion of FDP from its insertion by forced hyperextension Most common in the ring finger Leddy and Parker classification Based on the level to which the tendon retracts Status of the tendon vascular anatomy

29. Type I Profundus has retracted proximally into the palm Surgery should be done in 7-10 days before a fixed muscular contracture develops Least common Distal digital exposure to confirm diagnosis In Type I, a second distal palm incision will be needed Tendon is reinserted into the base of distal phalanx Distally based periosteal flap is raised distal to volar plate Tendon is sutured through drill holes in the distal phalanx and button tied over the nail plate

30. Type II Profundus retracts to PIP Disruption of Vinculum Breve Nutrition is maintained by Vinculum longum May be repaired up to 3 months Delay may convert type II into a type I if longum subsequently ruptures

31. Type III Attached bone fragment that fractures off the volar base of distal phalanx A4 pulley prevents proximal retraction Both Vinculae are preserved Type III attention is turned to ORIF

32. Complications Short term: Infection Injury to neurovascular structures or pulley system Abnormal scarring Long term: Adhesion Rupture Joint contracture triggering Adhesion Most common complication despite early motion protocols Tenolysis when patients progressive gain in digital motion has plateaued, usually 3-6 months after repair

33. Quadriga effect Tendon advancement shortens the FDP & completes the grip before the normal fingers, if the tension on tendon graft is set too high, and limit their flexion and thus week grip

34. Two stage technique Create a supple pseudosynovial sheath by implanting a silicone rod Soft tissue coverage or pulley reconstruction is performed at the first stage 8 weeks later, when psuedosynovial sheath is formed, the rod is replaced by a tendon graft 1. Palmaris longus and plantaris 2. Tendon grafts that include synovial sheath

35. Tendon Juncture Pulvertaft weave, with two or more passes through the proximal motor tendon

36. Distal end may be secured in multiple ways

37. Tension adjustment Proximal weave is adjusted Wrist is extended to flex the fingers into the cascade of the hand Overcorrect slightly because some stretching occurs after surgery

38. PULLEY RECONSTRUCTION Must be done during the first stage Well-healed pulley reconstruction facilitates early mobilization and gliding of tendon graft Reconstruction during the second stage increases the likelihood of pulley rupture and adhesion formation Material used Autogenous grafts: PL, Plantaris , to extensors, EIP, Extensor retinaculum, fascia lata

39. Flexor compartment of thumb.

40. Kleinert Protocol  Combines dorsal extension block with rubber-band traction proximal to wrist  Originally, included a nylon loop placed through the nail, and around the nail is placed a rubber band  This passively flexes fingers, & the patient actively extends within the limits of the splint

41. Duran protocol At surgery, a dorsal extension-block splint is applied with the wrist at 20-30° of flexion, the MCP joints at 50-60° of flexion, and the IP joints straight

42. Extensor Tendons 1 . Extrinsic System radial N innervated 2. Intrinsic System ulnar and median N innervated Extrinsic Extensors  Wrist Extensors: ECRL, ECRB, ECU  Finger Extensors: EDC, EIP, EDQM  Thumb Extensors: APL, EPL, EPB EDC has a common muscle belly with multiple tendons EIP & EDM lie on the ulnar side of the respective EDC tendon

43. Thumb Extensors APL inserts on the metacarpal and radially abducts it EPB inserts on proximal phalanx and extends MCP Joint EPL inserts on distal phalanx and extends IP Joint Testing the Extrinsics : APL:Palpate with thumb abduction EPB:MP extension with IP flexion, palpate tendon EPL:Palpate tendon with retropulsed thumb EDC:Test with wrist in neutral-extension

44. Vascularity & Innervation  Volar and dorsal metacarpal vessels  Median nerve supplies radial one or 2 lumbricals  Ulnar nerve supplies ulnar 2 lumbricals

45. Extensor Apparatus EDC tendon trifurcates into central slip & 2 lateral slips Intrinsic extensor tendons join the lateral slips to form the lateral bands Winslow’s Rhombus The central slip inserting on the base of the middle-phalanx and two lateral slips inserting to the distal-phalanx.

46. Lateral band:

47. Juncturae Tendinium Functional roles: spacing of ED tendons force redistribution coordinate extension MP stabilization Ring finger has least independent extension due to the orientation of the juncturae The most common patterns single extensor indicis proprius inserting to the ulnar side of the index extensor digitorum communis a single extensor digitorum communis to the index finger a single extensor digitorum communis to the long finger, a double extensor digitorum communis to the ring finger, an absent extensor digitorum communis to the small finger, and a double extensor digiti quinti with double insertions

48. SAGITTAL BANDS Stabilize the common extensor during digital flexion over MCPJ Limit the excursion of the common extensor tendon during digital extension EDC allows extension of MP joint via insertion onto the sagittal bands There is usually no tendinous insertion of EDC to the dorsal base of the proximal phalanx No MP joint hyperextension: EDC extends MP, PIP, and DIP joints even in the absence of intrinsic muscle function. INTRINSIC PARALYSIS: “slack” develops in EDC system distal to the sagittal bands all producing a flexion posture at PIP and DIP joints, the “claw” finger.

49. Transverse & oblique fibres of Interosseous Hood Transverse & oblique fibres of Interosseous Hood 1) EDC Tendon 2) Central Slip 3) Lateral Slip 4) Intertendinous Connection 5) Volar Interosseous Muscle 6) Lumbrical Muscle

50. Triangular Ligament Connects both lateral bands over the middle phalanx. • Limits the volar and lateral shifting of the lateral conjoined extensor tendon during digital flexion • In boutonniere deformity; elongated • In fixed swan neck deformity; retracted

51. Retinacular Ligament Lateral continuation of the triangular ligament extending from the lateral margin of the lateral conjoined extensor tendon to PIPJ articular volar plat

52. Extensor Tendon Injury Extensor apparatus Extrinsic muscles (ED, EI, EDM) Intrinsic Muscles ( Lumbricals and Interossei ) Fixed fibrous structures. Zone 1 • Mallet finger – persistent flexon of distal phalanx • Closed: splinting 6-8 weeks • Open: suture repair, Soft tissue reconstruction

53. Pullout Wire and K pin

54. Zone II injury- Middle Phalanx Level: • Repair by interrupted suture. • Immobilization for 5-6 weeks • DIP joint in extension • PIP joint left free

55. Zone III injury- PIP joint level Most complex anatomically and physiologically Causes two deformities Boutonniere disruption of central tendon Closed : splinting MCP and PIP in hyperextension for 6 weeks Open : suture repair (figure of 8 suture) Swan Neck excessive traction of central tendon Closed: splinting DIP & Open: suture repair

56. Zone IV injury- shaft of proximal phalanx level Repair relatively easy Adhesion is the problem

57. Zone V injury – MP joint level. Closed: splinting, 45 extension at wrist and 20 flexion at MCP & Open: suture repair by 5.0 prolene Zone VI injury- Metacarpal level Better prognosis than in fingers All structures, even inter- tendinous band should be repaired. Core type suture possible. Delayed suture is possible. Zone VII- wrist level Extensor tendons are under dorsal retinaculum. Retinaculum should be repaired or partially preserved. Adhesion is the problem Grasping core suture should be used. Immobilization for 5-6 weeks.

58. IMMOBILIZATION Keep the tendon in a shortened position through splinting or casting Tendons immobilized for 3 weeks In week 4, gentle active motion of the repaired tendon is introduced Rehabilitation depends on zone of injury

59. IMMOBILIZATION INJURIES IN ZONES PROXIMAL TO MCPs INJURIES IN ZONES DISTAL TO MCPs May be immobilized for 3 weeks . Afterwards, finger may be placed in removable volar splint between exercise periods for 2 weeks Progressive ROM after 3 weeks I f full flexion is not regained rapidly, dynamic flexion may be started after 6 weeks R equire a longer period of immobilization (usually 6 weeks ) A progressive exercise program is initiated D ynamic splinting during day and static splinting at night to maintain extension

60. EARLY PASSIVE MOTION Extensors are held in extension by dynamic, gentle rubber band traction, and the patient is allowed to actively flex the fingers—passively moving repaired extensor tendons

61. EARLY ACTIVE MOTION E arly active short arc program (developed by Evans) allows tendon to actively move 3 days after surgery Therapist must take care to ensure stress applied by early active motion does not overpower strength of surgical repair Splinting program is complex and specific and requires a skilled occupational therapist

62. Manchester Short Splint. Wrist Finishes at dorsal wrist crease Allows 45 degrees extension MCPJ 30 degrees flexion Exercises Commence 4 th or 5 th day Motion initiated at DIPJ

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