1. Flexor Tendon Injuries of the Hand David P. Moss, MD

2. Evaluation Perform prior to digital block! Skin Posture – extended finger Is finger perfused? –Cap refill –Doppler signal –Digital Allen’s test Digital nerves – radial & ulnar

3. Wound inspection May see lacerated tendon May be misleading –Flexed fingers at injury –Extended fingers at examination

5. FDS examination Adjacent finger DIPs, PIPs, and MCPs are held in full extension to eliminate FDP action Ask patient to actively flex at PIP Perform each finger seperately Can not rule out partial tendon injury

6. FDP examination Isolate DIP joint by grasping middle phalanx Ask patient to flex DIP

7. Imaging Xray –Avulsion fractures (Jersey fingers) –Foreign bodies MRI/Ultrasound –More commonly used in delayed presentation of closed injuries

8. Anatomy

9. Zones

10. FDS decussation at A1 pulley 2 FDS slips rotate 180° around FDP Slips rejoin at PIP – Camper’s Chiasm Insert on P2

11. Pulleys A2 & A4 –Originate off P1 & P2 –Most important to prevent bowstringing A1, A3, A5 originate off palmar plates A2 –Approximately 2 cm long –Can resect up to 50% if needed

12. 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

13. Treatment

14. Timing of repair 3 weeks –Commonly referenced –The earlier the better (easier) Emergent repair if impaired vascularity >3 weeks – possible reconstruction

15. Zone I Jersey finger, lacerations

16. Leddy classification Type I: retraction into the palm –Repair in 7-10 days due to disrupted vascularity Type II: retraction to PIP joint –Vincula intact, prohibit further retraction –Repair up to 6 weeks Type III: avulsed with volar lip of P3 –Can not retract past A4 pulley (DIP joint) –Repair up to 6 weeks Type IV: tendon avulsed off bony fragment

17. Zone I Fixation Leddy I: repair within 3 weeks Leddy II or III: repair up to 6 weeks Bone anchors into P3 –1 or 2 microanchors Pull through sutures over nail plate or button

18. Zone II: “no man’s land”

19. Historically poor results Adhesions, limited motion Fraught with complications

20. Core suture Repair strength directly related to number of core sutures At least 4 core sutures for early AROM Types: Kessler, Strickland, cruciate, etc.

22. Epitendinous Suture Enhances repair strength by up to 50% Smooths tendon, decreases bulk

23. Gap formation >3 mm gap → ↓ strength at 3 & 6 wks

24. Post-op care Splint 3-5 days to allow swelling to subside Then early AROM –May increase repair site strength –Commitment to hand therapy is critical PROM also used Advance activity over 2-3 months Unrestricted use at 3 months

25. Partial tendon lacerations Repair if >60% lacerated <60% → debride if entrapped –Hard to distinguish without direct visualization

26. On the horizon Fiberwire –4-0 looped Lubricants –5-Fluorouracil (mitotic inhibitor) –Hyaluronic acid

27. Quadriga Uninjured fingers unable to fully flex Usually due to shortening of injured flexor Common FDP muscle belly to SF, RF, MF Flexion excursion of other fingers is limited by the shortest tendon (usually injured finger)

28. Swan Neck DIP flexion, PIP hyperextension Mallet + lax/injured PIP volar plate

29. Boutonniere DIP hyperextension + PIP flexion Central slip avulsion Triangular ligament injury → volar migration of lateral bands

32. Lumbrical plus Paradoxical extension of IPs with attempted forceful flexion –IP extension – intrinsics –MCP flexion – intrinsics –IP flexion – FDP/FDS –MCP extension – EDC/EIP/EDQ

33. Causes: –FDP laceration distal to lumbrical origin Lumbricals originate on FDP just distal to TCL Insert into extensor hood – act to extend IPs

34. Causes: –FDP graft too long –Amputation distal to central slip insertion –All due to altered tension of FDP – load applied to lumbrical first –Imbalance

35. Board points

36. Anatomy Nerve compressions –Ulnar nerve (AMECF) Arcade of struthers Medial intermuscular septum Epicondyle Cubital tunnel FCU –Radial nerve (FLEAS) Fibers off lat IM septum Leash of henry ECRB Arcade of frohse Supinator Median nerve (SLAPS) –Supracondylar process –Ligament of struthers SC process – med epicondyle –Aponeurosis (lacertus fibrosis) –Pronator –FDS

37. EIP – last muscle innervated by PIN Parona’s space –potential space volar to PQ –Thenar space infection can communicate to hypothenar Space of Poirier – weak space in volar carpal ligaments b/w RSC and RLT ligs Contents of carpal tunnel

38. APL – multiple tendon slips to release in Dequervain’s dz TCL – floor of Guyon’s canal

39. Dual innervated muscles FPB – median and ulnar Lumbricals –IF & MF – Median –RF & SF – Ulnar Brachialis – Musculocutaneous & Radial