ACHIEVING IMMEDIATE ACTIVE MOTION BYUSING RELATIVE MOTION SPLINTING AFTERLONG EXRfENSORREPAIR AND SAGITTALBAND RUPTURES WITH TENDONSUBLUXATION

WYNDELL H. MERRITT, MD, FACS, JULIANNE HOWELL, PT, MS, CHT,REGINA TUNE, OT, MS, CHT, SANDRA SAUNDERS, PT, MS, CHT,AND MAUREEN HARDY, PT, MS, CHT

In compliant adult patients with extensor tendon laceration(s) in zones V to VII,relative motion spl intin.; of thelacerated tendon(s) provides support from the intact tendon(s), allowing immediate active motion and a less morbidcourse. Cadaver study shows how this simple splint allows full-finger interphalangeal and metacarpophalangealactive motion, except for 100 to 150 less metacarpal phalangeal total active motion of the repaired digit(s). Relativemotion splinting also permits immediate active motion after tendon graft reconstruction of extensor subluxation fromsagittal band rupture at the metacarpophalangeal joint, creating a centralizing pulley vith the graft.Copyright © 2000by WB.Saunders Company

KEY WORDS: extensor, tendon repair, subluxation, sagittal band, splint

The hand is an organ; one injured part elicits a responsein the entire organ. Extensor tendon lacerations may sufferthe greatest morbidity and the least attention of any handinjury. This is because of changes that occur in the unin-jured adjacent structures rather than in the laceratedtendon itself. Macrophages activated by an injured tendondo not discriminate between the uninjured volar plate, thecollateral ligament, and the intact joint capsule adjacent tothe injury. These structures undergo fibroplasia and re-model so that loss of motion occurs, even though there issuccessful tendon repair and extension. In fact, loss offlexion after repair and immobilization, not loss of exten-sion, is reported as the most common complication.'Dynamic splinting preserves active flexion and passiveextension, but it is cumbersome, therapy-intensive, anddoes not allow much function. For over 20 years we haveused relative motion splinting, which permits immediateactive motion and functional use in reliable patients,whom we encourage to return to work.

RATIONALE

'{he extensor digitorum communis functions as a singlemuscle system with 4 tendons, and the indeper.dent

From the Medi· al College of Virginia. Richmond. VA; Albany GeneralHospital. Albany. OR; and St Dominic Hospital and University of Missis-sippi Medical Center. Jackson. MS.

Address reprint requests to Wyndell H. Merritt. MD. FACS. 2002 BremoRd. Suite 202, Richmond, VA 23226.

Copyright © 2000 by WB. Saunders Company1071-0949/00/0701-0002$10.00/0doi:1 0.1053/oa.2000.5972

extensor indicis proprius and digiti quinti function syner-gistically, so essentially, the long finger extensors functionas a single motor unit. This provides opportunity to reducetension in repaired tendons by placing them in 10° to 15°more extension than their intact neighbors. The resultantslack allows active extension by reducing suture linetension, regardless of the active motion at the metacarpalphalangeal (MP) and interphalangeal joints (Figs 1 and 2).Full active finger flexion (except for 10° to 15° less at theMP joint in repaired tendon[s]) is encouraged. However, toavoid passive tension, the wrist is splinted to prevent fullwrist flexion at the time of full finger flexion (Fig 2).Cadaver study demonstrates the effectiveness of this splint-ing technique (Fig 3). One can also demonstrate its effective-ness by placing a sterile tongue blade beneath the freshlyrepaired digit and above the adjacent digits and watchingthe repair as the patient flexes and extends the digits underlocal anesthesia. This management technique has also beenused for immediate motion and use after centralizing subluxa-ting extensors with a tend -m gra.. pulley reconstruction.

INDICATIONS AND PROTOCOL

Relative rnotioi. splinting is indicated in adult patientswith 1 to 3 long extensor tendon Iaceu tions. .vho arewilling to remain in a splint that supports them by meansof the remaining intact tendons. This treatment is notapplicable when all extensor digitorum communis tendonsare lacerated. In that situation dynamic splinting is usuallythe best management method. A study of 180 patients overa lO-year interval showed that the results were signifi-cantly better if the tendon was repaired and the patientsplinted within 5 days of injury?

Operative Techniques in Plastic and Reconstructive Surgery. Vol 7. No 1 (February). 2000: pp 31-37 31

Fig 1. The extensorsfunction as a single mo-tor system, so placing theinjured digit in 10° to 15°more extension allows ac-tive motion.

Fig 2. Full active flexion and extension is encouraged immediately after repair and splinting.

Fig 3. Pull on the cadaver extensor digitorum communis muscle belly demonstrates lack of tension on the lacerated splintedtendon.

32 MERRITT ET AL

Fig 4. Two thermoplastic splints are initially used.

Our protocol is adjusted for each individual patient.However, the protocol generally used is as follows:

• First 3 to 4 weeks: Two splints used (Fig 4), with wristsplinted at approximately 25° of extension and fingersplinted with the injured digit in 10° to 15° moreextension than the adjacent digits at the MP joint. Thesplint passes beneath the proximal phalanx of the injureddigit and on the top (dorsum) of the proximal phalangesof digits with intact long extensors (Fig 2). With injured

perimeter digits (index or fifth finger), the splint passesabove the central 2 digits (Figs 5 and 6). Patients areencouraged to resume full work activity with the limitations imposed only by the splint.

• 4 to 6 weeks: The wrist portion of the splint is discontin-ued, but finger pan is continued (or a buddy splint isused in the last week) .

• 6 weeks: No further splinting is usually needed, and fullsplint-free activity is resumed.

Saldana! compared dynamic and relative motion splintingtechniques after extensor repair and prefers the latter.However, he used the relative motion splinting techniquefor only 4 weeks without complications, so our 6-weekregimen may be unnecessary.

EXTENSOR SUBLUXATION DUE TOSAGITTAL BAND DISRUPTIONFor nonrheumatoid patients who develop subluxation ofthe extensor tendons at the MP joint due to trauma,degeneration, epilepsy, congenital factors, or spontaneouscause, conventional treatment has included protecting thetendons from use for 8 to 10 weeks. Tendon use is restrictedby either a dorsal tenodesis from adjacent tendon or a slingfrom the sub luxating tendon to the adjacent intrinsic. Bothrequire 10 weeks during which unprotected use is notpermitted." In a unique case in which an elderly patientsubluxed both radially and ulnarly (Fig 7), conventionaltechniques were not applicable, and the use of relativemotion splinting allowed immediate active motion and useafter centralization with a tendon graft pulley (Figs 8 and9). The splint protected the pulley repair. This treatment.has now become our procedure of choice for subluxatingtendons, and we have had success also in trauma cases.

Fig 5. Immediately afterfifth digit extensor re-pairs, protection is pro-vided by a tongue bladeuntil splints are made.

IMMEDIATE ACTIVE MOTION AFTER EXTENSOR REPAIR 33

Fig 6. For perimeter digit repairs (index and fifth fingers), the central 2 digits are beneath the splint.

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Fig 7. Painful extensor subluxations to both radial and ulnar sides with a history of steroid injection.

34 MERRITT ET AL

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IMMEDIATE ACTIVE MOTION AFTER EXTENSOR REPAIR

Fig 8. Drill holes were connected in the metacarpal head, and ajuncturae tendinum graft was passed through the bone andaround the tendons to centralize it with a pulley, with the graftsuture line rotated into the bone.

/

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Fig 9. Relative motion splinting prevented tension on the pulley graft to allow immediate motion and use while keeping thetendon centralized.

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Fi;; 10. Patients "/h') arenot permit "d to w=arsplints at work mav par-ticularlv enjoy the advan-taqes of relative motion'jp:inting.

MERRITI ET AL

DISCUSSIONIn a series of 180 patients with 1 tc 3 lacerated extensortendons studied r.ver a lO-year interval, relative motionsplinting permitted 98 OJ,) recovery 0: flexion and 96'Y.,recovery of total active motion compared with the normaluninjured sidc.? There were no ruptures and no cases ofreflex dystrophy. Our best results vere in those patientswho were repaired and splinted within 5 days of injury,with results in patients treated later more comparable toconventional immobilization techniques." The greatest ad-vantage of this technique was the immediate active useand encouragement to return to work with overall lesstherapy needed (Fig 10). Therapists were asked to checkthe patients within a few days after splinting to be sure thatfull active flexion was recovered and to continue checkingonce a week until splinting was discontinued. If patientswere reluctant to recover flexior a more active therapyprogram was used. This manage-ment method fulfills theaxiom, "The greatest challenge in treating hand injury is to

IMMEDIATE ACTIVE MOTION AFTER EXTENSOR REPAIR

preserve function in all of the structures not directlyinjured.":' Because this splinting technique results in muchless morbidity, we have been pleased with it and recom-TI'2ndits use.

REFERENCES

1. Blair '.V, Newport M, Speyers J r C: Long-term results of extensortendon repair. J Hand Surg [Am] 15:961-966, 1990

2. Merritt W, Howell J: Immediate active use following -xtensor tendonrepair and relative motion splinting, in Proceedings of the SixthCongress of the IFSSH. Bologna, ltaly, Monduzzi Editore, 1995

3. Saldana M: Comparison of the "Merritt" splint to dynamic splintingtollowing extensor tendon repair. American Association for HandSurgery Annual Meeting Proceedings, Phoenix, AZ, Fall, 1997 (abstr)

4. Burton R, Melchior T: Extensor tendons-late reconstruction, in GreenD, Hotchkiss R, Pederson VV(eds): Green's Operative Hand Surgery(cd 4). Philadelphia, r'A, Churchill Livingstone, 1999, pp 1998-1999

5. Merritt W: Written on behalf of the stiff finger. J Hand Ther 11:74-79,1998

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