Tendon Function & Innervation. Extensor Tendon Rehabilitation. Thumb. Rebecca J Saunders, PT/CHT. Muscle/Tendon Functions

Transcription

1 Tendon Function & Innervation Extensor Tendon Rehabilitation Rebecca J Saunders, PT/CHT Curtis National Hand Center Baltimore, MD October 6-8, 2017 Wrist extension (radial n.): Extensor carpi radialis longus (ECRL) Extensor carpi radialis brevis (ECRB) Extensor carpi ulnaris (ECU) MP extension (radial PIN): Extensor digitorium communis (EDC) Extensor indicis proprius (EIP) Extensor digiti minimi (EDM) PIP extension: Interosseous (ulnar n.) Lumbricals (median and ulnar n.) EDC, EIP, EDM (radial n.) Muscle/Tendon Functions PIP extension: UN, MN, RN Interossei: UN Lumbricals: MN & UN ED, EIP, EDM: RN DIP extension: RN DIP extension is the combined action of ED, lateral bands, and tenodesis effect of spiral oblique retinacular ligament The terminal extensor tendon serves to extend the DIP joint in synchrony with the PIP joint Thumb Thumb CMC extension / abduction (radial n.): Extensor pollicis longus (EPL) Extensor pollicis brevis (EPB) Abductor pollicis longus (APL) Abductor pollicis brevis (APB), median n. Thumb MP extension (radial n.): Extensor pollicis brevis (EPB) Thumb IP extension (radial n.): Extensor pollicis longus (EPL) Muscle/Tendon Functions Wrist extension: RN 1. Extensor Carpi Radialis Longus 2. Extensor Carpi Radialis Brevis Muscle/Tendon Functions MP Extension: RN Extensor Digitorium Communis (PIN) Extensor Indicis Proprius (PIN) Extensor Digiti Quinti Minimi (PIN) 3. Extensor Carpi Ulnaris (PIN) 5 6

2 Muscle/Tendon Functions: Thumb Thumb CMC extension/abduction: RN 3. Abductor Pollicis Longus (PIN) 4. Extensor Pollicis Brevis (PIN) 5. Extensor Pollicis Longus (PIN) Abductor Pollicis Brevis (Median N) Thumb MP extension: Extensor Pollicis Brevis Thumb IP extension: Extensor Pollicis Longus How Extensor Tendons Differ from Flexor Tendons Dorsum of hand revealing extensor tendons of Zones 5 7 Anatomy more complex Tendons are flatter, more superficial, largely extrasynovial Can rapidly adhere to underlying bones and joints Often heal with a lag secondary to adhesions Weaker than digital flexors 7 8 Vascular Supply Sources of blood flow to the extensors include the radial and ulnar arteries, the dorsal branches of the anterior interosseous artery, and the vessels of the deep palmar arch Extrinsic blood supply Synovial fluid also provides nutrition to the extensor tendons, especially under the extensor retinaculum Extrinsic blood supply also includes vessels from muscle origin/insertion and scar tissue during healing stages Digital Extension The extensor mechanism is comprised of both extrinsic and intrinsic systems. The extrinsic system is radial nerve innervated. The intrinsics are median and ulnar nerve innervated. The precise length relationships between the central slip, lateral band, terminal tendon, and the interweaving of fibers make restoration of extension difficult. Extensor quadriga: Pathomechanics and treatment Shrikant J Chinchalkar BScOT OTR CHT, Bing Siang Gan MD PhD FRCSC FACS, Robert M McFarlane MD FRCSC, Graham J King MD FRCSC, James H Roth MD FRCSC FACS Can J Plast Surg Vol 12 No 4 Winter 2004 available in Google scholar 10 Extensor Mechanism Extrinsic Extensor Anatomy Central Slip Sagittal Bands Central Extensor (EDC + EIP/EDQ) (Netter as cited in Hu, Howard, & Ren, 2014)

3 Intrinsic Extensor Anatomy Triangular Ligament EIP & EDQ on ulnar side of EDC Extensor Hand Juncturae tendinum Terminal Tendon Lateral Bands Lumbrical & Interossei EDC slips (variable) Broad intertendinous connections Connect RF to MF/SF Assist extension of adjacent digit by transferring forces during extension Laceration of an ET proximally to JT can mask the injury Juncturae Tendinum 1 st : APL/EPB 2 nd : ECRL/ECRB 3 rd : EPL 4 th : EIP/EDC 5 th : EDQ aka EDM 6 th : ECU Extensor Wrist Need to consider gliding individual tendon in sheath and under retinaculum Extensor Tendon Zones Zone I: DIP Zone II: Middle phalanx (P2) Zone III: PIP Zone IV: Proximal phalanx (P1) Zone V: MP Zone VI: Metacarpals Zone VII: Extensor retinaculum Zone VIII: distal forearm Zone IX: musculotendinous junction It is much easier to prevent an extension lag than it is to fix one! The emphasis in therapy for all zones of injury is on maintaining extension while making gradual gains in flexion.

4 Work capacity Beware of the patient with that far away look in his eye Flexors are 3 4 times stronger than the extensors Emphasize gradual gains in flexion while maintaining extension Therapy Management of Acute Extensor Ruptures Acute Extensor Ruptures Mallet Finger a.k.a. Baseball Finger mallet describes appearance of flexed DIP joint occurs from loss of extensor mechanism integrity at the base of the distal phalanx may be 2ary to laceration or avulsion of distal extensor tendon or from a fracture that involves the extensor tendon insertion closed injuries (avulsions or fractures) treated with extension splinting (6&6) of the DIP joint unless there is a large fracture fragment with joint subluxation Immobilize for 6 8 weeks in full extension Dorsal or volar splints must support the DIP joint continuously in full extension PIP mobilization in splint day 1 Watch for development of swanneck posture add PIP flex component at 30 flex Zone I/II: Mallet Finger open injuries typically repaired Prevent swan neck deformity!!

5 Mallet Deformity with Swan Neck Watch for development of swan neck posture with hypermobile patients Splint PIP in degrees of flexion, can be separate component Dorsal PIP splint makes performing PIP flexion ROM easier Zone I and II need to monitor skin integrity and position in splint avoid extreme hyperextension may affect circulation Rayan and Mullins suggest splint position of hyperextension just short of skin blanching and that circulation was compromised at splinting beyond 15 hyperextension DIP 0 extension to slight hyperextension PIP free Stack splints,, molded thermoplastic usually volar may be dorsal 2 splint regimen Can also use quick cast or Orficast thermoplastic tape with reliable patients Zone I and II skin maceration can be a problem pts. must be careful to avoid flexion during hand washing can line splints with moleskin to absorb perspiration can issue 2 splints one for showering must adjust splint for edema, see patient more frequently during first week especially if it is a bony mallet Splint PIP in 30 flexion daytime if needed, and at night if patient is developing PIP hyperextension Gradual orthosisweaning 1 st 2 weeks use PM and between exercises Gradually decrease wearing time Morning, afternoon, evening, Continue night splinting Rehabilitation Composite flexion Avoidance of isolated joint motion 2 schools of thought here! Lateral tracing of digit to monitor lag Can be measured by: goniometry lateral tracings if lag increase by 5 or more, immobilize for 2 add l weeks then restart protocol LAG Courtesy of Rebecca Neiduski

6 Zone I and II Wk 7: flexion reps hourly Wk 8: 35 flexion IF NO LAG! use templates for the overly ambitious patient resplint if lag develops continue splint between exercise periods Exercises: 7 8 weeks: full fisting / hook fisting blocking for DIP extension / flexion weeks: gentle passive DIP flexion (if no lag present) D/C day splinting at 8 10 weeks post injury continue night splinting for add l 4 wks. After day splint D/C d Gradually increase flexion Begin with rolling large cylinders progress to rolling smaller cylinders Emphasis on maintaining extension Strengthen extensors prior to starting grip strengthening Boutonniere Deformity ( buttonhole ) PIP flexion and DIP hyperextension Causes: central slip/triangular ligament rupture or PIP synovitis Lateral bands slide volar

7 Zone III/IV: Boutonniere Deformity Stage I Dynamic boutonniere that is passively mobile Stage II Established deformity that cannot be corrected passively Immobilization of PIP in full extension for 6 8 weeks Active flexion of DIP to maintain length of oblique retinacular ligament and facilitate gliding of lateral bands Recommend reassessing the central slip function at 2 3 weeks and if the patient has active extension then start gradual remobilization using SAM or a relative motion MP flexion splint with continued use of PIP ext orthosis between exercises and PM Zone III/IV: Boutonniere Deformity Stage III/IV Established deformity with resultant structural changes of the PIP joint Surgical release of PIP and correction of extensor mechanism as needed Acute Extensor Ruptures Central slip injury with or without triangular ligament rupture Elson s test can help determine if a boutonniere deformity is likely to occur if the PIP joint is not splinted/protected for a sufficient amount of time When in doubt, assume worst injury until proven otherwise Elson s Test PIP is full flexed and held in the fully flexed position The patient is asked to extend the fingertip with the PIP joint held in flexion If central slip is intact, the lateral bands will be slack and incapable of extending the DIP If central slip is injured, tension will be transmitted through the lateral bands to the DIP and extend, which would be POSITIVE (Image courtesy of Donald Sammut) Zone III/IV: Boutonniere Deformity Lateral bands transmit force towards PIP flexion and DIP hyperextension PIP flexion contracture Pseudoboutonniere the DIP joint remains passively flexible True boutonniere the DIP joint cannot be passively flexed Rehabilitation Achieve full passive PIP extension using dynamic, static progressive, serial static splints or casts Must be held in extension for 6 weeks prior to remobilization

8 Aggressive DIP flexion with PIP supported in full extension during immobilization phase Begin Active PIP ext with just relaxing into flex and focus on active extension Orthotic use PM and when not performing exercises 4 5 times per day Add passive PIP flexion Two weeks or more after splinting is discontinued If flexion is not increasing (and extension remains good) Monitor extension closely as activities in flexion progress Rehabilitation Relative motion splinting for boutonniere For the passively supple boutonniere Wendell Merritt J Hand Surg Am 2014 Splint MP of affected digit in less MP extension and allow full excursion Splint PIP s in extension at night for weeks after initiating mobilization Splint PIP in ext intermittently daytime if there is a lag Chronic boutonnieres require orthotic or casting to restore passive ext first; may require use of relative flexion splint for 3 months after initiating mobilization phase Merritt recommends accepting a 30 lag with chronic bouts who plateau during attempts at regaining full extension; then full time use of Relative Extension splint for 3 months Boutonniere Deformity of Thumb Swan Neck Deformity Postural collapse deformity Can begin at MP, PIP, or DIP joints Pathology begins at MP joint Most common thumb deformity in RA 45 PIP hyperextension with DIP flexion 46 Swan Neck Deformity Splinting for Swan Neck Deformity Thermoplastic Figure 8 Four possible causes: Terminal tendon rupture PIP hyperextension from lax volar capsule 2 to synovitis or rupture of volar plate FDS rupture (loss of dynamic PIP stabilization) Intrinsic tightness 2 to MP pathology Oval 8 splint 47 48

9 Swan Neck Deformity of the Thumb Pathology begins with subluxation of 1 st CMC joint 49 Sagittal Band Rupture The sagittal bands prevent bowstringing of the ED during extension, centralize ED at midline during flexion Rupture is usually atraumatic, involving radial fibers Can cause ED to sublux ulnarly and can cause incomplete extension 50 Sagittal Band Repair Techniques Sagittal Band Splinting Splint to immobilize a sagittal band rupture Vaughn Jackson Lesion Tendon rupture of ED to 4 th & 5 th fingers at ulnar styloid Often seen in RA Will require surgery Tendon repair vs. transfer Name this deformity A B 53

10 Therapy Management of Acute Extensor Lacerations Tajima repair Protocols = Guidelines Types of Protocols Static immobilization Used for young, cognitively impaired or uncooperative patients Early Controlled Mobilization Used for zones III VIII Early Active Mobilization Used for zones III VIII Rehabilitation Zones III IV Conservative management PIP joint immobilization at 0 extension 6 8 weeks Initiate AROM at 6 8 weeks Orthosis use in between exercises and PM Gradually increase flexion activities while monitoring extension lag D/C of orthosis determined by AROM and response to exercise/functional use of hand Rehabilitation zones III,IV Zone III injury is frequently complex Immediate passive extension Outrigger orthosis supporting the PIP at 0 with rubber band traction 30 degrees of flexion or more allowed at PIP joint initially Walsh et al., 1994 JHT Thomes, 1995 JHT Gradually increase flexion excursion Start AROM at 5 weeks per Thomes Protective splinting D/C d at 6 weeks Relative Motion Flexion orthosis blocking MP in slight flexion to facilitate IP ext through Interossei and lumbrical. (not the standard of care for acute repairs) This orthosis can be used following D/C of the dynamic orthosis to help decrease extension lag if present.

11 Early Short Arc Motion of the Repaired Central Slip Evans JHS 1994 Rehabilitation zones III,IV Short arc motion (SAM) Evans JHS Nov 1994 McAuliffe JA JHS Jan 2011 Early Active Short Arc Motion Following Central Slip Repair John A. McAuliffe, MD JHS Jan 2011 PIP and DIP immobilized at 0 extension between exercise Wrist positioned in 30 degrees flex, MP s neutral for exercises Template with 30 PIP and 20 DIP flexion Finger flexion to the template with active extension to reps every 1 2 hours Template progressed weekly If lateral bands were repaired DIP flex is limited to 30 with the PIP at neutral Zones IV, V Zone V: MP Joint Radians Brand noted that no other area in the human body has a ratio of tendon to bone as unfavorable as it is over the proximal phalanx Intimacy of periosteum and extensor mechanism as well as gliding requirements in this area make it prone to functional deficits due to adhesions Based on intra operative and cadaver studies of Evans and Burkhalter MPJ: IF/MF 30⁰, RF/SF 40⁰ create 3-5 mm glide in ZONE V Zone V VII Conservative Management Zone V Wrist 30⁰ extension MPs 0 20 flexion IP s neutral or can be free with MP s neutral Zone VI VII Wrist in extension Minamikawa Y, et al: Wrist position and extensor tendon amplitude following repair JHS 17: , 1992 Zone V VII: Immediate Passive/Active Extension Dynamic extension splint Volar block/stop allowing 30 MP flexion Volar forearm based resting splint with MP s at neutral Evans & Thompson, Passive wrist extension, MPs relax to wrist relaxes to 0 to 20 flexion (Zones V VI) 10 extension (Zone VII) 20 extension if wrist extensors are repaired

12 Rehabilitation Immediate Controlled Active Motion Following Zone 4 7 Extensor Tendon Repair ]Howell, Merritt, Robinson J HAND THER. 2005;18: Initiate AROM carefully at 3 weeks continuing splint use PM and after exercises 4 5 times per day MP flexion with IPs extended Hook fist : PIP/DIP flexion with MP extension Progress to composite digital AROM after 4 weeks Progress to composite wrist and digital flexion at 5 weeks Monitor extensor lags closely Timely initiation of scar management D/C splint generally at 6 wks, wrist ext repairs require protection for 2 additional weeks due to the work demands on the wrist Immediate Controlled Active Motion (ICAM) Concept based on relative motion of the MP joint Wrist placed at extension MPs in more extension relative to other MP joints ICAM Protocol Inclusion criteria Injury to at least one but not all extensor tendon(s) in zone visits in first 10 days 1 visit per week thereafter Phase days post repair Edema and scar management Both splint components worn continuously Goal: Full active motion within limits of splint ICAM Protocol Phase days post repair Yoke splint worn at all times Wrist splint removed for active wrist motion Goal: Composite wrist/digit flexion and extension without extensor lag Phase days post repair Wrist splint discarded; yoke or buddy strap worn during activity Yoke splint removed for active digital motion

13 ICAM Outcomes Robinson et al., 1986 ASHT Annual Meeting, New Orleans 22 patients full ROM within 5 weeks of surgery, joint stiffness was nonexistent and no patient required a therapy program after removal of the splint Howell et al., patients No extension lag: 114 patients 5 10 lag: 21 patients lag: 5 patients Average discharge 49 days No complications or secondary surgeries Zones IV VI: EDC, EIP, EDQ Most studies agree that some form of early motion improves outcomes of rupture, gapping, scar adhesions, AROM and grip when compared to immobilization protocols. Cost savings in tenolysis surgery and subsequent therapy May actually be better for low compliance patients than immobilization Choice of orthoses and exercise programs to fit injury and patient needs Zones V VI: EDC, EIP, EDQ: Immobilization Least expensive in terms of orthotic fabrication and initial therapy visits Easiest therapy program for patient to follow May result in stiff joints, scar adhesions, more time off work, and orthosis removal if patient gets frustrated with ADL performance HEP Orthosis on at all times Move IP joints freely D/C orthosis at 6 weeks Zones VII: ECRL,ECRB,EDM,EDC,EIP,EDQ EDC/EIP/EDQ involved Orthosis = Forearm based, wrist ext, MPs ext Wrist extensors only Orthosis wrist cock up at 30 extension x 6 weeks HEP Initiate AROM wrist at 4 weeks p.o. Synergistic wrist ext/flex Progress to fingers with modified fist with wrist flexion Progress to full composite wrist/finger ext/flex Conclusion Zone I II needs immobilization >6 weeks All other zones may have better outcomes with early controlled AROM Injuries involving fractures, crush, or other soft tissue involvement need early controlled AROM to decrease the likelihood of secondary complications Allowing 2 3 days before initiating therapy minimizes inflammatory response

14 Thumb zones T1 treat similar to mallet if closed, 6 8 wks continuous immobilization; if repaired 5 6 weeks of immobilization Always check the amount of IP ext present on the uninjured thumb Require 4 more weeks of orthotic use once mobilized Gradual increments of flex as long as extension is maintained Mild resistive pinch/grip between 6 8 weeks dependent on if a lag is present T2 hand based splint MP/IP at neutral with radial extension Short Arc active motion at 3 wks; continue orthotic use PM and post ex for 6 weeks Evans RB: Clinical management of extensor tendon injuries in Skirven et al: Rehabilitation of the Hand 6 th ed Evans RB: Managing the Injured Tendon: Current Concepts J Hand Ther: 2012 Thumb zones T3,4 forearm based splint wrist 30 degrees, MP neutral and slight CMC abduction T5 early motion should be considered to prevent dense adhesions at the retinaculum Evans and Burkhalter found intraoperatively that with wrist neutral and MP neutral 60 IP flex created 3 5 mm glide at Lister s tubercle Use dynamic ext orthosis Passive motion in therapy of 30 MP flex with wrist/ip extended; wrist tenodesis with thumb in ext from full ext to 0 ; Zone T 5: Conservative Treatment Begin gentle motion at 3 4 weeks for conservative treatment. Dense adhesions form to the thumb extensors. Tendon at this level is synovial 84

15 Early Controlled Passive Motion Protocol: Thumb T5 Thumb T5: Early Controlled Passive Motion Thumb IP will need 60 of flexion to achieve 5mm of tendon gliding with wrist in neutral & MP at weeks Dynamic extension splint with wrist in extension and MP at 0 A volar block allows 60 of IP flexion with sling returning the IP to 0 between reps and at rest 3 weeks Remove volar block to allow IP flexion as tolerated Add active thumb IP extension 4 5 weeks Continue dynamic splinting at home In therapy, begin gentle composite flexion/extension of thumb 6 weeks (d/c dynamic extension splint Begin PROM to thumb as needed If extensor lag is present, add night extension splinting Zones V VII: EPL, EPB, APL Orthosis Thumb: EPL Wrist 20 extension, CMC RAb, MP/IP 0 ext Exercise In clinic: Passive wrist extension with thumb supported; IP flexion to 60 (5 mm glide) Wrist in 20 flexion, Place/hold IP extension Difference in early active group clinically significant at 8 wks for IP and MP extension and thumb retropulsion No ruptures in either group Orthosis Thumb: EPB, APL Wrist 20 extension, Thumb functional position Early active motion for EPL Zones T III V Evaluating outcomes

16 Outcomes of Extensor Tendon repair Newport, Blair et al JHS Nov 1990 % of digits losing flexion > % losing extension More distal zones have significantly > number of poor results (I IV) Zone V: 83% Good Excellent When associated with a fracture results dropped to 50% (G E) A specialist knows the worst mistakes which can be made in his field and how best to avoid them Nils Bohr Extensor Tendon Management References Von Schroeder HP, Botte MI: Anatomy and functional significance of the long extensors to the fingers and thumb. Clin Orthop 2001;20:74 83 Matzon JL, Bozentka DJ: Extensor tendon injuries. J Hand Surg 2010;35A: Evans RB: An update on extensor tendon management. In Hunter JM, Mackin EJ, Callahan AD: (Eds.): Rehabilitation of the Hand: Surgery and Therapy, 4th ed. St Louis, Mosby, 1995, pp Gelberman RH, Manske PR: Effects of early motion on the tendon healing process: experimental studies. In Hunter JM, Schneider LH, Mackin EJ (Eds.): Tendon Surgery in the Hand. St Louis, Mosby, 1987, pp Gelberman RH, Steinberg D, Amiel D: Fibroblast chemotaxis after repair. J Hand Surg Am 1991;16: Horii E, Lin GT, Cooney WP: Comparative flexor tendon excursions after passive mobilization: an in vitro study. J Hand Surg Am 1992;17: Evans RB, Burkhalter WE: A study of the dynamic anatomy of extensor tendons and implications for treatment. J Hand Surg Am 1986;11: Evans RB, Thompson DE: An analysis of factors that support early active short arc motion of the repaired central slip. J Hand Ther 1992;5: Evans RB: Early active short arc motion for the repaired central slip. J Hand Surg Am 1994;19: Evans RB Chapter 39: Clinical Management of Extensor Tendon Injuries: The Therapist s Perspective pg , in Skirven et al; Rehabilitation of the Hand, 6 th edition, Elsevier 2011 Crosby CA, Wehbe MA: Early protected motion after extensor tendon repair. J Hand Surg Am 1999;24: Dy CJ, Rosenblatt L, Lee SK; Current methods and biomechanics of extensor tendon repairs. Hand Clin2013;29: Extensor Tendon Management References cont. Tubiana R: Extensor apparatus of the fingers. In Hunter JM, Schneider LH, Mackin, EJ (Eds.): Tendon Surgery in the Hand. St Louis, Mosby, 1984, pp Newport ML, Blair WF, Steyers CM: Long term results of extensor tendon repair. J Hand Surg Am 1990;15: Newport ML: Early repair of extensor tendon injuries. In Berger RA, Weiss AC (Eds.): Hand Surgery, Vol 1. Philadelphia, Lippincott Williams & Wilkins, 2003, pp Tang JB: Tendon injuries across the world: Treatment. Injury 2006;37: Mowlavi A, Burns M, Brown RE: Dynamic versus static orthotic use of simple zone V and zone VI extensor tendon repairs: a prospective, randomized, controlled study. Plast Reconstr Surg 2005;115: Howell J, Merritt W, Robinson S: Immediate controlled active motion following zone 4 7 extensor tendon repair J Hand Ther 2005;18: Merritt W: Relative motion orthotic: active motion after extensor tendon injury and repair J Hand Surg Am 2014;39: Sameem M, Ignacy T, Thoma A, Strumas N: A systematic review of rehabilitation protocols after surgical repair of the extensor tendons in zones V VIII of the hand; J Hand Ther 2011;24: Ng CY, Macdonald DJ, Mehta SS, et al.: Rehabilitation regimens following surgical repair of extensor tendon injuries of the hand a systematic review of controlled trials. J Hand Microsurg 2012;4:65 73 Von Schroeder HP, Botte MI: Anatomy and functional significance of the long extensors to the fingers and thumb. Clin Orthop 2001;20: Saunders RJ: Chapter 20 Management of Extensor Tendon Repairs,pp in Burke et al: Hand and Upper Extremity Rehabilitation A Practical Guide, 3 rd ed Elsevier 2006 Saunders RJ: Chapter 20 Management of Extensor Tendon Repairs, p in Saunders et al: Hand and Upper Extremity Rehabilitation A Practical Guide, 4 th Ed Elsevier 2015