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David E. Ruchelsman, MD, et alFigure 4Type V avulsion injury of the flexor digitorum profundus(FDP) tendon defined by concomitant osseous distalphalanx avulsion and comminuted distal phalanx fracture.Preoperative fluoroscopic AP (A) and lateral (B) viewsdemonstrating a comminuted intra-articular distal phalanxfracture. Intraoperative fluoroscopic AP (C) and lateral (D)views following Kirschner wire fixation of the dorsal fracturefragment of the distal phalanx base to the shaft. E, Intraoperative photograph of a Bruner approach, exposing incarceration of the FDP tendon under the A4 pulley. F, Advancement of the FDP tendon through the pulley system. G, Thecompleted repair of the FDP tendon using a pulloutsuture–dorsal button technique.mandated distinct methods of management.The relative incidences of pureFDP tendon avulsions, and those sustained in association with distal phalanx osseous avulsion fracture, remain difficult to quantify; there areno large studies dedicated to the clinical spectrum of FDP tendon injuryMarch 2011, Vol 19, No 3patterns. Based on our review ofavailable case series limited by relatively small cohorts, Leddy andPacker1 type I, II, and III injuries arethe most common. Types IV and Vare seen with less frequency. Approximately 50% of FDP tendon avulsions are associated with an osseousfragment.Clinical and RadiographicExaminationPhysical examination of the patientwith a suspected FDP tendon avulsion injury is relatively straightforward. The pathognomonic finding isinability to actively flex the DIPjoint.18 The cascade of the fingers is155

Avulsion Injuries of the Flexor Digitorum Profundus Tendondisrupted, and the involved digitrests in a more extended position.Acute pain can obscure the diagnosisby inhibiting active flexion of the entire finger, including at the PIP joint.A local digital anesthetic block isuseful in eliminating pain so as toobtain a better assessment of the active motion of the finger. To avoid adelay in diagnosis, isolation of DIPand PIP active joint motion is essential.The course of the fibro-osseoussheath and flexor tendon of the involved digit should be palpated.Identification of the point of maximal tenderness may represent thesubcutaneous location of the avulsedtendon stump.19 Local pain, swelling,and ecchymosis are associated findings. Localizing the extent of stumpretraction is a critical component ofthe preoperative assessment becausethe level of retraction plays an important role in dictating the approach to management.Radiographs of the involved digitare obtained to assess for underlyingfractures or bony avulsion fragments. When the physical examination is unrevealing or equivocal, theuse of ultrasonography as a modalityfor distal tendon stump localizationhas been described, but it is operatordependent.20 MRI also may be used.In general, these advanced imagingmodalities may be more helpful inthe chronic setting rather than withacute injury, when surgical exploration and repair are recommended regardless of the level of tendon retraction.Prognostic FactorsIn regard to clinical outcome, severalprognostic factors have been identified. The level of proximal tendonretraction is directly related to themagnitude of disruption of the vincular system. The preserved vascular156supply to the profundus tendon mayinclude both the VLP and sheath synovial fluid via diffusion. The chronicity of the avulsion injury is alsoan important preoperative consideration and affects treatment options.The presence and size of associatedosseous fragments and distal phalanx fracture have ramifications onthe reconstructive strategy selected.ManagementManagement options are based onthe time elapsed since injury (acute,10 to 14 days; subacute, 14 days to 4to 6 weeks; and chronic, 6 weeks),extent of proximal FDP tendon retraction and vincular system disruption, bone fragment size, and Leddyand Packer avulsion type.1 Expeditious management is recommendedin all cases because the tendon mayretract more proximally than the associated fracture pattern suggests.21In cases of subacute rupture, myostatic contracture may prevent fulladvancement of the FDP tendon toits insertion site. Following exposure, a suture is positioned in the distal aspect of the tendon, and steadytraction is placed on the myotendinous junction for several minutes. Adirect repair is performed when thepulley system can be dilated and theFDP tendon brought to its insertionsite without tightening the cascademore than 1 cm of tip-to-palm distance compared with the adjacentdigits. In these cases, it is imperativeto splint the proximal interphalangeal joint in neutral to prevent a flexion contracture.If the tendon cannot be passed under the collapsed pulleys, or if the repair will shorten the tendon 1 to1.5 cm, then management options include the following: (1) wound closure, observation, and possible laterDIP joint fusion if unstable (the patient should have 5/5 PIP joint flex-ion strength preoperatively); (2) immediate DIP joint fusion (the patientshould have 5/5 PIP joint flexionstrength preoperatively); (3) primarytendon graft (if the pulleys are adequate, but myostatic contracture prevents advancement of the tendonstump to its insertion); or (4) twostage tendon reconstruction withplacement of a silicone rod if pulleysare collapsed at the time of the primary exploration. A thorough preoperative discussion with the patientregarding intraoperative concernsand the approach to treatment is essential.Chronic injuries secondary to delayed patient presentation or diagnosis are managed on a case-by-casebasis after careful consideration ofpatient-specific factors. Staged graftreconstruction is reserved for a select, small group of patients and isundertaken only after full disclosureof the possible risk of decreasedproximal interphalangeal joint motion with this approach. In our experience, most patients have functionalPIP joint motion and may be treatednonsurgically or, if symptomatic,with DIP joint arthrodesis.Type I and II InjuriesThe ideal surgical repair should sustain functional loads to facilitateearly postoperative mobilization andtherapy. Surgical options include adorsal button (pullout versus nonpullout suture), direct tie aroundbone, suture anchor, or a combination of button-anchor techniques. Anattempt is made to localize the levelof retraction preoperatively based onexamination and supplemental imaging modalities. The proximal tendonis identified using a Bruner approach22 or midaxial incisions andadvanced through the fibro-osseousflexor tendon system to the distalphalanx. Often, it is necessary to dilate the pulley system to advance theJournal of the American Academy of Orthopaedic Surgeons

David E. Ruchelsman, MD, et alFigure 5Illustration of a completed flexor digitorum profundus tendon repair achievedusing a dorsal button technique.avulsed tendon. It is paramount thatthe FDP tendon be passed throughthe Camper chiasma anatomically.Although the cruciate pulleys may beincised, great care is taken to preserve the competence of the A2 andA4 pulleys. Independent of the repairtechnique used, the FDP tendonshould not be advanced more than 1to 1.5 cm to avoid creating quadrigasyndrome (ie, flexion lag in the adjacent digits when the injured FDPis improperly tensioned—“over-advanced”—because the remaining fingers share a common muscle belly).Intraoperatively, restoration of thedigital cascade with progressive digital flexion from radial to ulnar mustbe confirmed.Dorsal Button TechniqueThe original repair method describedby Bunnell23 included a pullout suture–dorsal button combination.Since then, there have been manymodifications.In the dorsal button technique,once the tendon is advanced, theFDP tendon remnant may be split inthe midline, to be used for reinforcement at the end of the repair. Thedistal phalanx just distal to the volarplate insertion is identified andsharply cleared of any remaining softtissue to allow for direct tendon-toMarch 2011, Vol 19, No 3bone healing. An unlocked corestitch (eg, Bunnell or Kessler stitch)using a 2-0 monofilament with twoor four strands is placed in the FDPtendon terminal end. For example, a2-0 monofilament can be used topass two different Bunnell sutureswith three passes each, one pair dorsally and one pair volarly. To avoidthe germinal matrix, a Keith needleis drilled from proximal volar to distal dorsal, out the nail bed and nailplate, several millimeters distal to thelunula. The paired sutures composing this four-strand repair are tiedover a button. Nonabsorbable 3-0 or4-0 braided suture on a tapered needle may be used to suture the FDPtendon remnant on the distal phalanx to the FDP tendon as reinforcement (Figure 5).Alternatives to tying over a buttonare to pass the suture material directly around the distal phalanx orthrough the nail plate, via two separate holes, and then tie it directlyover the nail plate.24,25 Recently, abuttonless fixation technique via adrill hole was described by Teo et al26in a series of 18 patients. They useda modified Kessler suture tied internally through drill holes, providingtransosseous internal fixation, andshowed favorable outcomes. Biome-chanical analyses by Silva et al27demonstrated similar tensile loads tofailure for three common pullout suture configurations (Bunnell andKleinert, 39 N, respectively; Kessler,30 N), which surpass the tensile loadof 20 N created with unresisted, active digital flexion.Generally, the disadvantage ofpullout suture techniques is that thefixation point of the tendon-to-boneand the suture knot is a relativelylarge distance, leading to excessivetendon-to-bone gapping, especiallywith use of monofilament suture material.28,29 Complications of this technique include possible nail plate deformity and/or possible nail foldnecrosis, reliance on direct tendonto-bone healing within 6 weeks, andthe need to protect the pullout sutureconfiguration. In our experience,when care is taken to avoid pressureto the eponychium, button complications are rare. Technical pearls include exiting well distal to the lunula, placing the button with theconvex side onto the nail plate overtwo-ply cotton padding, and trimming the circumference of the buttonso that there is no impingement onthe surrounding skin.Suture Anchor TechniqueThe suture anchor technique (Figure6) for FDP tendon avulsion repairsfollows the principles of this fixationmethod when it is used in other anatomic locations for musculotendinous repairs or reconstructions. Different anchor sizes are available (eg,Micro and Mini suture anchors[DePuy Mitek, Raynham, MA]); selection is based on the dimensions ofthe distal phalanx. Pilot holes aretypically drilled at a 45 angle fromdistal-volar to proximal-dorsal, inaccordance with the deadman angletheory of suture anchors, to increasethe resistance to pullout of the implant.30 Furthermore, more bone isavailable at the proximal-dorsal cor-157

Avulsion Injuries of the Flexor Digitorum Profundus TendonFigure 6A, Schematic drawing of the suture anchor technique illustrating the deadman angle. B, Intraoperative fluoroscopicimage demonstrating retrograde insertion of the anchor without violation of the articular surface.ner to avoid any possibility of dorsalperforation by the anchor.Schreuder et al30 simulated type IFDP tendon avulsions in 18 freshfrozen fingers and performed repairswith dual Micro suture anchors)with 3-0 Ethibond (Ethicon, Somerville, NJ) and a modified Bunnell unlocked core suture. Biomechanicaltesting demonstrated that gap formation was lowest in the 45 retrogradeinsertion group, but load to failurewas similar in all three groups ( 30N). In a comparative study of sutureanchors to pullout button techniques, Brustein et al31 reported thatthe mean load to failure of the pullout button group (43.3 4.8 N) andof the single 1.8-mm Mini anchor(44.6 12.7 N) were inferior (P 0.001) to that of a dual 1.3-mm Micro suture anchor technique (69.6 10.8 N). All failures in the pulloutbutton group occurred by suturerupture at the knot tied over the button. In contrast, failures in the anchor groups occurred by either suture rupture at anchor attachment oranchor pullout of bone. In an in vivocyclical testing protocol simulatingpassive digital mobilization, Latendresse et al32 concluded that both thepullout button and Micro suture anchor fixation techniques are inadequate to support postoperative activedigital motion.158Intraoperative fluoroscopy (Figure6) is used to ensure that there hasnot been penetration of the dorsalcortex or DIP joint. The terminaledge of the FDP tendon must beflush with the underlying bone to allow for direct tendon-bone healing.Advantages of using the suture anchor technique include complete internalization of the suture and avoidance of potential nail plate deformityand a dorsal incision. Additionally,suture anchors allow for the use oflocked suture repair techniques andpermanent tendon-to-bone fixation.This technique may be suboptimal inosteoporotic bone or contraindicatedin an avulsion injury with an associated distal phalanx fracture.29 Use ofanchors typically requires some advancement of the FDP tendon, whichmay increase the risk of a DIP jointcontracture. Surface repair has alsobeen found to cause a reduction inbone density by 40% in a caninemodel; this phenomenon theoretically increases the risk of clinicalfailure.33-35Despite these potential limitationsto the suture anchor technique,McCallister et al25 reported similarclinical outcomes at 1 year postoperatively in a consecutive, nonrandomized, retrospective cohort of 26 patients following either modifiedpullout button or dual suture anchorzone 1 FDP tendon avulsion repairs.No significant differences in sensibility, active digital arc of motion, DIPjoint flexion contracture, or gripstrength were seen between the twocohorts. Furthermore, there were nofailures or revision surgeries in eithergroup following identical postoperative rehabilitation protocols. However, suture anchor repair did yield asignificantly more rapid return towork (P 0.05).25Evidence-based Premisesfor ManagementBecause of variable biomechanicaltesting protocols, along with multiple suture materials, core suture configurations, and the anchor types (eg,variable anchor number, size, configurations) that can be used, universalrecommendations cannot be madeon either button or anchor repair asthe optimal repair for these injuries.27,28,30,31,33,36 However, assessmentof the literature does provide premises for evidence-based treatment:multi-strand repairs perform better;37locking suture configurations arebiomechanically superior;26 nonabsorbable braided suture material, inparticular FiberWire (Arthrex, Naples, FL), is preferred;29 gapping continues to be seen with pullout suture–dorsal button repairs; twoMicro anchors are better than oneJournal of the American Academy of Orthopaedic Surgeons

David E. Ruchelsman, MD, et alanchor;27,32 and failure via bone pullout remains a concern with sutureanchor methods.Type III Through V InjuryA variety of osseous fixation constructs may be considered in themanagement of type III, IV, and Vinjuries to address the large avulsionfragment and/or the associated distalphalanx fracture. Mini Fragmentscrews38 (Synthes, Paoli, PA), interosseous wires,39 and Kirschnerwires have yielded satisfactory outcomes. When the fragment is sufficiently large in type III injuries, MiniFragment plate (Synthes) fixationmay be considered.40 In select cases,fragment excision followed by a direct tendon-to-bone repair techniquemay be performed. In contrast withtype I and II FDP tendon avulsion injuries, the preservation of the vinculasystem may make type III injuriesamenable to late primary repair.Postoperative ProtocolIntraoperatively, a dorsal blocksplint is made so that the end of thesplint extends 2 to 3 cm beyond thefingertips. The wrist is positioned atzero degrees of extension, the metacarpophalangeal joints are maximally flexed (70 to 90 ), and the interphalangeal joints are placed inneutral. Care is taken to avoid anypressure or any firm restriction onthe volar aspect of the fingers. Eventhe most compliant patient may actively flex the fingers during sleep;therefore, there should be nothingvolar to the fingertip that would provide resistance in case of accidentalfinger flexion. At the initial postoperative visit (ie, 4 to 7 days), a substantial improvement in the postoperative edema is often noted.41The postoperative motion protocolinstituted depends on multiple factors. These include the qualities ofMarch 2011, Vol 19, No 3the tendon and that of the repair itself, the stability of fixation of anyassociated fractures, and patientspecific factors. If a strong repair isachieved, early gentle motion may beinitiated in a compliant patient. Tohelp meet this goal, we now use asuture anchor and dorsal buttoncombination to create a four-strandlocking repair with braided nonabsorbable suture. In our experience,controlled active motion with wristtenodesis can be started postoperatively with this technique in a reliable patient. Place-and-hold exercises with blocking is started atapproximately 4 weeks postoperatively. This exercise entails passivelyflexing the interphalangeal joints andasking the patient to actively holdthe flexed position. Blocking is performed by using a contralateral finger to isolate the joint and facilitatedifferential gliding between the FDSmuscle and FDP tendon so as to minimize intratendinous adhesions. Mildresistive exercises are started at 10weeks. Until 6 months postoperatively, the patient is prohibited fromheavy lifting or from engaging insports that require strong handgrasping.Outcomes andComplicationsClinical outcome following FDP tendon avulsion injuries depends on several factors; these include the extentof the injury, chronicity, the qualityof the tendon repair and/or osseousstabilization, and the complianceand motivation of the patient. Postoperative rehabilitation is crucialand emphasizes the importance ofopen communication between thehand surgeon, the patient, and thetherapist. Published reports estimatean average loss of 10 to 15 of DIPjoint extension.1 In a small seriesconsisting of type II and type III inju-ries, Moiemen and Elliot39 reportedthat two thirds of patients had 50%of full DIP joint range of motion andonly 22% had good to excellent DIPjoint motion. This was in contrast tothe findings of McCallister et al,25who reported considerably greaterDIP joint motion, although there wasno comparison with the contralateralside.DIP joint stiffness and/or contracture is commonly seen followingFDP tendon avulsion injury repair, afact that reinforces the importance ofa proper postoperative rehabilitationprotocol and a motivated patient.Other complications include repairre-rupture or loss of fixation. FDPtendon advancement 1 cm can result in the quadriga effect and manifests as weakness in pinch and gripstrength. In injuries with associatedfractures, there is an increased incidence of arthrosis and joint instability. Infection, although uncommon,can have devastating results on therepair and on postoperative outcome.Late Management andSalvage OptionsThe management of chronic FDPtendon avulsions secondary to latepatient presentation or missed FDPtendon avulsion injuries is dependenton the

David E. Ruchelsman, MD Dimitrios Christoforou, MD Bradley Wasserman, MD Steve K. Lee, MD Michael E. Rettig, MD From the Hand and Upper Extremity Service, Department of Orthopaedic Surgery, Massachusetts General Hospital/Harvard Medical School, Boston, MA (Dr. Ruchelsman), and Hand Surgery, PC, Department of Orthopaedic Surgery, Newton-File Size: 512KBPage Count: 11