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Sesamoid and toe fractures
Injury, Int. J. Care Injured (2004) 35, S-B87—S-B97
Sesamoid and toe fractures Thomas Mittlmeier, Patrick Haar Chirurgische Klinik und Poliklinik der Universität Rostock, Abteilung für Unfall- und Wiederherstellungschirurgie, 18055 Rostock, Germany
KEYWORDS: Toe fracture; crush injury; sesamoid fracture; stress fracture; fracture-dislocation.
Summary1 Injuries of the toes and sesamoids of the first metatarsophalangeal joint comprise a wide spectrum of traumatic entities. Despite the fact that a majority of lesions may well respond to nonsurgical treatment and exhibit an excellent prognosis, appropriate clinical and imaging analysis is mandatory to select those injuries that require specific therapeutic and surgical measures to avoid long-term sequelae of functional disability.
Introduction Fractures of the toes represent the most common fracture of the forefoot, with an incidence of 140 cases per 100,000 population per year and a male: female ratio of 1.6 [3, 27]. While it may be true that the overwhelming majority of phalangeal fractures of the lesser toes does not result in a relevant clinical disability independent of any residual malalignment, the same statement may not be valid for dislocated fractures of the great toe, particularly intraarticular or complex fractures, physeal injuries in children, fracture-dislocation of the first metatarsophalangeal joint or interphalangeal joint dislocation, and chronic overuse injuries as in hallucal sesamoid bone stress fractures [3, 18]. In particular, the last of these injuries may confront the doctor with a variety of differential diagnoses. If the correct diagnosis is missed, incapacitating pain may result [24]. Concomitant morbidity, eg, diabetes mellitus with sensory neuropathy, may be a reason why a toe fracture is not primarily diagnosed, only becoming apparent due to secondary complications. Crush injuries of the forefoot from machine-related (eg, lawnmower injuries) or industrial injuries (eg, dropping of a heavy weight onto the foot) do generally involve the toes and require a profound expertise in management of complex fractures with severe damage of the soft tissue envelope [27]. 1
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Correspondingly, the mechanisms of injury range from low-energy trauma due to indirect forces (eg, a hyperextension injury of the metatarsophalangeal or interphalangeal joint of the hallux, “stubbed toe” or the “bedroom” or “night-walker” fracture of the fifth digit due to abductory forces) to high-energy trauma and direct force impaction following a fall or a motorcycle or motor vehicle accident (eg, leading to a complex dislocation of the first metatarsophalangeal joint [7, 12, 21, 22]). Consequently, as trauma severity increases, the chance of concurrent injuries of the proximal forefoot and midfoot areas increases [7]. Thus, the wide field of injury patterns in the toe area underlines the fact that diagnosis and treatment of injuries at the toe area are not as trivial as it might appear at first glance. In the following sections, the spectrum of acute and chronic injuries in the toe area will be discussed with particular reference to diagnostic and therapeutic options.
Clinical evaluation The history of direct or indirect trauma and the clinical image of the distal forefoot—which is easily accessible to clinical assessment with manifestation of regional pain, hematoma, ecchymosis, tenderness and swelling, deformity, crepitation, pain during active and passive motion and the disability to bear weight and initiate the roll-over process—usually makes it easy to localize the site of injury. Subungual
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hematoma is a hallmark of distal phalangeal fractures [3]. The diagnosis might be rendered more difficult if the initial clinical presentation of trauma is oligosymptomatic as in some physeal injuries of the distal phalanx of a stubbed toe in children, where subungual bleeding may be the only hint of an open injury and later sequelae such as osteomyelitis and growth arrest may develop [10, 18]. In addition, trauma may be overlooked if it is not perceived by patients with systemic metabolic disease (eg, diabetes mellitus) or neurological disorders leading to peripheral somatosensory deficits. Chronic trauma such as stress fractures of the sesamoids also may create differential diagnostic problems as with sesamoiditis, osteochondritis dissecans, avascular necrosis, adventitious bursitis, and tenosynovitis of the flexor hallucis longus [4, 25, 26]. Progressive activity-related pain and swelling underneath the first metatarsal head will lead to the correct working diagnosis. A vibrating tuning fork is a helpful diagnostic tool as it causes local discomfort in patients with a stress fracture [27].
Radiographic examination and imaging techniques Anteriorposterior, medial and lateral oblique views of the forefoot should be evaluated if acute frac-
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tures or chronic problems of the toe area without exact limitation of the trauma or combined injuries are suspected (Fig. 1a, b). The medial oblique view is helpful in assessing the tibial sesamoid, and the lateral oblique view aids evaluation of the lateral sesamoid [24]. Bilateral exposures can be helpful for discriminating between traumatic and non-traumatic issues (Fig. 1c). Focused images are indicated if the injury is well confined or for follow-up reasons [27]. A lateral view of the complete toe area is not very helpful for displaying the single rays since the structures overlap. Strictly lateral views of single rays may be advantageous in certain types of dorso-plantar dislocation. An axial or skyline view of the sesamoids should be performed in those cases where a pathological condition of the sesamoids is assumed (Fig. 2a—c). Fluoroscopy is particularly helpful in merely ligamentous injuries, where stress testing can prove the degree of instability that might be hidden in standard static x-ray views. This technique can also be applied to patients who manifest dislocations or fracture-dislocations of the toes to demonstrate the chance of closed reduction or the corresponding irreducibility necessitating open reduction. Stress sesamoid views can visualize displacement of the sesamoid complex with dorsiflexion of the great toe, which gives an indirect hint at a rupture of the plantar plate if
Fig. 1: (a) Standard x-ray dorsoplantar view of the forefoot. (b) Medial oblique view of the forefoot. (c) Bilateral comparative dorsoplantar view of the forefoot.
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distal migration of the sesamoids with dorsiflexion does not occur. In chronic problems weight-bearing x-rays of both feet usually clearly depict the site of the deformity or instability [11, 19]. Technetium bone scanning may be useful for demonstrating increased activity in stress fractures, particularly if comparing both feet in unilateral problems [5, 27]. However, one has to bear in mind that an increased asymmetric scintigraphic activity may occur in up to 29% of asymptomatic persons [24]. CT and MRI scans including 2-D reconstructions can be particularly indicated for analyzing sesamoid fractures and posttraumatic soft tissue pathology and for differentiating traumatic and non-traumatic conditions (compare Figure 3, (p. 90) [4, 5, 11, 27]).
Fig. 2: (a, b) Apparatus for axial sesamoid view (“skyline view”). (c) Radiographic example of bilateral skyline view.
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Specific injuries Phalangeal fractures Some authors separate hallucal phalangeal fractures from lesser toe fractures by alluding to the larger and functionally more important phalanges of the hallux [29]. Phalangeal fractures generally occur following direct trauma (stubbing injury or crushing injury when an object is dropped on the foot), with the lesser toe fractures being the commonest injuries [3, 29]. Abduction injuries such as the „night-walker fracture“ of the fifth toe, which may occur while ambulating barefoot in the dark, are another typical injury mechanism [10]. Depending on the energy of direct trauma, the nail bed is frequently involved in digital fractures [27]. Inadequate management of nail-bed trauma may lead to nail deformation, malalignment, splitting, or chronic infection [27]. An acute subungual hematoma with a concomitant intact nail should be decompressed, eg, by heating an uncoiled paper clip for perforation of the nail substance. If bleeding from the eponychium and/or laceration of the nail bed is present, open fracture of the distal phalanx should be suspected [18]. An open fracture should be assumed in children if the physis of the distal phalanx is involved, even in absence of the typical clinical signs of bleeding around the nail. The open fracture can be derived from the close vicinity of the skin and the periosteum at the nail root immediately above the corresponding physis [18]. Management according to the principles of open fractures can prevent infection, osseous growth arrest, and disturbance of nail growth [18]. The majority of closed nondisplaced or minimally displaced stable digital fractures can be immobilized by buddy taping to the adjacent digit(s) (Fig. 4).
Fig. 4: Buddy taping of a nondislocated fracture of a hallucal distal phalanx.
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Fig. 3: Differential diagnosis of sesamoid problems. (a, b) Contusion of the sesamoids: negative MRI, subsesamoid bursa. (c, d) Osteonecrosis of the left fibular sesamoid (x-rays). (e) Intact contralateral foot (skyline view). (f, g) Proof of osteonecrosis by MRI.
This technique generally allows for early full weightbearing in a shoe with a wide toe box and a rigid sole. Splinting should be renewed in defined time intervals to guarantee effective immobilization and to prevent such adverse effects as interdigital skin maceration [29]. While three weeks of splinting should be sufficient in children, a period of 4—5 weeks is recommended for adults [27]. Despite displaced phalangeal shaft fractures, particularly of the three central digits, rarely causing clinical disability, even in the presence of manifest malalignment, it does not necessarily mean that closed reduction and immobilization should not be intended primarily [3, 27]. After induction of adequate local or regional anesthesia, longitudinal manual traction and manipulation of the corresponding digit, reverting the mechanism of injury, can re-
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Fig. 5: K-wire fixation of a shaft fracture of the proximal phalanx of the hallux. (a) View after trauma. (b, c) X-rays after ORIF.
store adequate alignment regarding length axis and rotation [27]. Simple reduction aids such as a pencil used as a fulcrum placed in the web space may be helpful for stabilizing the proximal fragment. Even comminuted fractures may successfully be molded into acceptable alignment of the digit [10]. The mode of immobilization, again, depends on the degree of instability after successful reduction, which must be documented by radiography. Transverse diaphyseal fractures represent quite stable fractures after reduction in contrast to oblique, spiral, or comminuted fracture variants, which require analogous techniques of immobilization to nondisplaced fractures. Nevertheless, a decision must be made in those cases where substantial deformity is still present after an attempt at closed reduction or in cases of dislocated joint fractures. Prior to any potentially open procedure, a thorough assessment of the soft tissue status, including the general status of the patient (eg, advanced arterial occlusive disease), is mandatory. On one hand, it is certainly true that limited use of hardware in the phalanges of the foot contributes to the avoidance of implant-related complications, on the other hand, however, painful
angular deformity and posttraumatic degenerative joint disease, particularly of the most medial or lateral digits may be the reason for profound functional disturbance. In the lesser toes, K-wires, cerclages or mini-screws are preferable to any bulky implant. Kwires offer the advantage of stabilization following closed reduction or reduction with minimum tissue dissection (eg, by use of percutaneously placed reduction forceps). However, due to their migration potential, additional immobilization with a cast (Fig. 5) is advisable. Therefore, in joint fractures or spiral or oblique diaphyseal fractures, mini-screws offer a substantially better primary stability (Fig. 6). Despite this fact, some authors state that secondary resection arthroplasty and dermoplasty could be an effective solution [10]. There is less variability in the approach towards a dislocated and/or unstable fracture of the hallux due to its role at push-off during the roll-over process. The importance of the first ray and the stability of the first MTP joint is already appreciated in patients following amputation injuries of the great toe [1]. A dislocated comminuted diaphyseal fracture or a bicondylar epi-/metaphyseal fracture of the proximal
Fig. 6: Screw fixation of shaft and joint fractures. (a, b) X-rays of a dislocated proximal phalanx fracture of the fifth toe. (c, d) X-rays after ORIF. (e, f) Monocondylar fracture of the proximal phalanx of the fourth toe.
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hallucal phalanx is well suited for application of a mini-plate (Fig. 7). Misinterpretation of a bicondylar fracture as a monocondylar tear-off fracture with underdimensioned postoperative stability will invariably lead to redislocation and indicate a revision procedure (Fig. 8). The rare occurrence of an avulsion fracture of the extensor insertion at the distal phalanx of the hallux should follow the same principles that represent the standard for treating a mallet finger [14, 23]. As such, surgery will only be indicated for marked plantar dislocation of the distal phlanx [14]. Open fractures, in particular, from crushing traumas such as in lawnmower injuries, are rarely limited to the toe region. Generally, compound bone-soft tissue injury represents a surgical emergency situation where the standard rules of treatment of complex trauma are to be followed to prevent infection and secondary loss of tissue due to progressive soft tissue damage. Systematic irrigation and radical
Fig. 7: Plate fixation of a comminuted fracture of the proximal phalanx of the hallux. (a) Preoperative view. (b, c) Postoperative x-rays.
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debridement in the operating room should be supplemented by provisional stabilization of fractures, preferably by K-wire transfixation that if necessary
Fig. 8: Misinterpretation of a bicondylar fracture of the proximal hallucal phalanx. (a) Post trauma. (b, c) Inadequate stabilization with two mini-screws. (d, e) Revision technique.
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can be converted into internal fixation at a later stage of tissue consolidation. At the earliest stage of treatment, an imminent or manifest compartment syndrome should be ruled out or detected. At best, prophylactic fasciotomy should be performed. There are rare indications for microvascular repair in the toe area [1], but, even a viable soft tissue flap of an otherwise destroyed toe might be useful for coverage of a forefoot defect. In amputation injuries, conservation of the stump of the proximal phalanx will be helpful for providing a buttress for the adjacent toes to prevent horizontal instability and secondary deformity [10].
Sesamoid fractures The two sesamoids at the first metatarsophalangeal joint level are well embedded in the capsuloligamentous complex (Fig. 9a); the medial (tibial) sesamoid being larger than the lateral (fibular) sesamoid, corresponding to its more important
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role in weight bearing within the medial sulcus of the metatarsal head. They are held together by the strong intersesamoid ligament and the plantar plate, which is firmly attached at the base of the proximal phalanx and loosely fixed at the neck of the metatarsal via the capsule. The sesamoids are enveloped within the two strands of the flexor hallucis brevis muscle. In addition, the abductor hallucis tendon inserts at the medial sesamoid, the adductor hallucis tendon at the fibular sesamoid. Strong collateral ligaments with two essential components, the metatarsophalangeal and metatarsosesamoid ligaments, support the first metatarsophalangeal joint at the medial and lateral side contributing together with the capsule and the extensor elements to an outstandingly high degree of stability of the first metatarsophalangeal joint [8, 24]. While the lateral sesamoid is rarely bipartite, a bipartite sesamoid can be found in 10% of the population. This condition is seen in both feet in 25%, which sometimes makes it difficult to differentiate between a symptomatic bipartite or multipartite
Fig. 9: (a) Normal anatomy of the first MTP joint and classification of dislocations of the MTP I joint. (b) Type IA dislocation. (c) Type IB dislocation. (d) Type IIA dislocation. (e) Type IIB dislocation. (f) Type IIC dislocation.
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sesamoid, a sesamoid fracture, or a fracture through a bipartite sesamoid [24]. Fractures in sesamoids may occur by direct trauma or by repetitive overuse (stress fracture) or during fracture-dislocation of the first metatarsophalangeal joint (see below). Stress fractures are generally found in athletes [4, 5, 24]. The non-characteristic onset of symptoms, with some swelling of the forefoot and exercise-related pain increased during forced dorsiflexion of the great toe, raises the differential diagnoses of sesamoiditis, chondromalacia, flexor hallucis brevis tendinitis, osteochondritis dissecans and avascular necrosis of the sesamoids, arthritis, localized plantar keratosis, and impingement of the medial plantar digital nerve [24, 25]. A thorough clinical examination preferably supplemented by bilateral standard x-rays will be the key to a conclusive diagnosis. The confirmation
Fig. 10: Acute medial sesamoid fracture. (a, b) X-rays of fractured tibial sesamoid. (c, d) Approach and intraoperative view. (e, f) Postoperative x-rays.
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of an unstable sesamoid stress fracture may be the radiographic proof of progressive separation of the fragments over time. With regard to the heterogeneity of fracture etiology and the low incidence of sesamoid fractures, the optimum choice of treatment remains unclear [5]. While initially a conservative treatment based on rest or partial weight bearing, cessation of sports, application of a short-leg walking cast for six weeks, or the supply of a molded orthosis for 6—8 weeks supported by antiphlogistic drugs is recommended by most authors, surgery is generally advised if nonoperative treatment fails [4, 5]. Due to the crucial role of force transmission of the sesamoids total sesamoidectomy without soft tissue reconstruction is rarely recommended. Partial (proximal) sesamoidectomy and reconstruction of the short flexor tendon
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has been shown to represent a reliable option to alleviate pain and allow return to a high level of activity [4]. Other authors have recommended autologous bone grafting in patients with symptomatic nonunion [26]. A minimum invasive technique using plantar percutaneous cannulated screw fixation appears to be such a successful alternative to open procedures for acute fractures, nonunions, and stress fractures that the authors question the importance of diagnosing the specific individual etiology [5]. Total sesamoidectomy should be avoided as it produces a mechanical defect in the flexor hallucis brevis tendon-muscle unit and reduces the flexion movement arm of the muscle at the metatarsophalangeal joint level [2, 24]. Therefore, total sesamoidectomy should only be applied in cases with recalcitrant inflammatory arthritis [24]. Excision of both sesamoids has a high potential of inducing hallux valgus or cock-up deformity of the hallux [24]. The open surgical approach for the tibial sesamoid is preferably a longitudinal low medial or medial plantar approach (Fig. 10) while the fibular sesamoid is exposed via a dorsal incision in the first web space or via a direct plantar approach. The corresponding plantar nerves should be spared. The tendons and capsule should be repaired meticulously [4, 24].
Sprains and dislocations/fracturedislocations A specific injury variant of the first metatarsophalangeal joint is that of a dorsiflexion injury leading to a sprain with and without lesion of the sesamoid complex. Sprains of the first metatarsophalangeal joint represent a common injury, particularly during sports, that is commonly referred to as „turf toe“ [8]. The incidence of this traumatic entity has risen with increasing popularity of artificial sports ground surfaces and the energy necessary to lead to the rare fracture-dislocation variants is substantially higher than the energy necessary to cause a turf toe [7]. Progressive traumatic hyperextension of the first metatarsophalangeal joint leads to a lesion of the plantar capsule at the metatarsal neck being weaker than the attachment at the proximal phalanx. Finally, compression injury at the dorsal articular surface of the metatarsal head can result in maximum hyperextension [8]. Clanton [8] has formulated three degrees of sprain severity characterizing the corresponding pathology at the first metatarsophalangeal joint. While a Degree 1 sprain corresponds to stretching of the capsulo-ligamentous complex with localized plantar medial tenderness and swelling and the preserved
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ability to bear weight, a Degree 2 sprain is characterized by plantar ecchymosis and the inability to perform sports due to a partial tear of the plantar capsulo-ligamentous complex. A Degree 3 sprain is marked by a more complete tear of the capsuloligamentous complex and often includes tearing of the plantar plate from its origin on the metatarsal head junction and an impaction of the proximal phalanx into the metatarsal head dorsally. A sesamoid fracture or a separation of a bipartite sesamoid may be included in this third stage. Sometimes, a distal rupture of the capsulo-ligamentous complex can be concluded from manifest proximal migration of the sesamoid complex. Clinically, the patient with a Degree 3 sprain is unable to bear weight on the medial forefoot with gross restriction of range of motion of the first metatarsophalangeal joint. Surgery is only indicated in the rare cases of sprain where instability, a dislocated sesamoid fracture or a loose osteochondral fragment within the joint space becomes apparent [8]. The overwhelming majority of patients can be treated non-surgically by protection, rest, ice, compression, and elevation (acronym “PRICE”) supplemented by nonsteroidal antiphlogistics. Remobilization of the patient is facilitated by prescribing inserts or recommending the wearing of a stiff-soled shoe. Repetitive trauma may lead to the development of hallux rigidus. In contrast to sprains, first metatarsophalangeal joint dislocations or fracture-dislocations are often associated with concomitant injuries of the midfoot and forefoot [7]. The underlying mechanism of injury is a combination of forefoot hyperextension, axial loading of the foot and midfoot hyperflexion. In 1980, Jahss published a classification comprising three types of complex dislocation of the first metatarsophalangeal joint (I, IIA, IIB) to which three further types (IA/B, IIC, III) have been added over the following years (Fig. 9b—f). In type I dislocations, the strong intersesamoid ligament remains intact. While in type IA dislocations, the hallux dislocates with proximal disruption of the sesamoid complex generally leading to irreducibility by closed means due to interposition of the plantar plate and the sesamoid block (buttonhole effect). Type IB may be overlooked initially as the dislocation with distal disruption of the sesamoid complex at its distal insertion may reduce spontaneously. This might be interpreted as a „sprain“ leading to a consecutive claw-toe deformity and loss of intrinsic strength. Type II dislocations are mostly reducible due to partial disruption of the sesamoid complex (type IIA intersesamoid ligament rupture, type IIB transverse fracture of one of the sesamoids, Fig. 9d, e). Type IIC represents a combination of types IIA and IIB (Fig. 9f). Widening of the
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intersesamoid distance is the common radiographic feature of type II injuries. Jahss has added a type III injury corresponding to a complete rupture of both conjoined tendons with intact sesamoids and plantar plate [13, 15, 22]. As a general recommendation, closed reduction should be attempted first by accentuating the deformity by further dorsiflexion followed by longitudinal traction and plantar flexion of the proximal phalanx [7, 12]. Joint stability and congruity should be assessed post reduction clinically and radiographically [3]. Persistent instability, a crepitation, an interposition of loose bodies in the joint space (widened joint space), and a dislocated sesamoid fracture represent indications for open revision, as in irreducible dislocations /fracture-dislocations. A dorsal or medial approach (particularly when the tibial sesamoid is fractured) is preferable to a plantar approach, which does not guarantee enough exposure of the underlying pathology [3]. Due to the variability and the relative rarity of the
Fig. 11: (a) Normal anatomy of the hallucal interphalangeal joint. (b) Type I dislocation: invagination of the ruptured plantar plate and the sesamoid bone. (c) Type II dislocation with completely displaced plantar plate with hyperextension and shortening deformity.
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trauma entity, no conclusive recommendations can be given regarding repair of the injured structures. Repair of the ruptured intersesamoid ligament is not addressed in the literature [13]. Depending on the site of fracture location and size of fragment(s), some authors prefer partial sesamoidectomy instead of fracture repair, including reconstruction of the residual sesamoid-tendon structures and the capsule [13]. There has been a number of authors presenting different directions of dislocations of the great toe that are even rarer than the types of dorsal dislocation [6, 21]. Principally, the approach towards diagnostics and the algorithm of treatment given for dorsal dislocations can be applied analogously. Dislocations of the lesser metatarsophalangeal joint also represent uncommon injuries [16, 20, 28]. Depending on the direction of dislocation, the interposed tendon of the flexor digitorum longus muscle (latero-dorsal dislocation) or the tendons of the extensor digitorum longus and brevis muscles (plantar dislocation) wrapped around the metatarsal head might represent an obstacle to closed reduction necessitating open revision. In chronic dislocation, the final outcome depends on anatomical reduction and total correction of secondarily contracted soft tissue structures [20]. Interphalangeal joint dislocation affects the first and fifth toes, again, being mostly the result of direct stubbing injury [3]. Two types of irreducible hallucal interphalangeal dislocation exist: the first where the ruptured plantar plate is invaginated into the widened joint space (Fig. 11b) and the second where the plantar plate and an interphalangeal sesamoid, which is present in more than 95% of adults, is dislocated dorsally to the head of the proximal phalanx, leading to a hyperextension deformity (Fig. 11c). A medial approach for irreducible dislocations seems preferable to the dorsal approach, which might expose the extensor apparatus to additional damage [9]. Blunt trauma of the middle phalanx of the fifth toe might resemble the radiographic appearance of a dislocation due to local swelling and hematoma, but may only be a pseudodislocation [27]. In general, fracture-dislocations of the metatarsophalangeal and interphalangeal joints will have a good prognosis if correct reduction and alignment of the joint is achieved; patients with permanent complaints are those with combined trauma (eg, additional Lisfranc joint involvement) or bilateral injuries [7]. Isolated injuries of single structures of the metatarsophalangeal joint (rupture of the adductor tendon, isolated traumatic dislocation of the lateral sesamoid, rupture of the medial collateral ligament) will only lead to long-term problems in exceptional situations [11, 17, 19].
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Conclusion Effective treatment of injuries of the distal forefoot essentially depends on the knowledge of the anatomy and the understanding of the biomechanical function of the involved structures. An under-appreciation of the functional value of the toes and the sesamoids is not justified at all. Adequate clinical assessment and diagnostic imaging offer the key to addressing those injuries properly.
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17. Irwin AS, Maffulli N, Wardlaw D (1995) Traumatic dislocation of the lateral sesamoid of the great toe: nonoperative management. J Orthop Trauma; 9(2):180—182. 18. Kensinger DR, Guille JT, Horn DB, et al (2001) The stubbed great toe: importance of early recognition and treatment of open fractures of the distal phalanx. J Pediatr Orthop; 21(1):31—34. 19. Labovitz JM, Kaczander BI (2000) Traumatic hallux varus repair utilizing a soft-tissue anchor: a case report. J Foot Ankle Surg; 39(2):120—123. 20. Leung WY, Wong SH, Lam JJ, et al (2001) Presentation of a missed injury of a metatarsophalangeal joint dislocation in the lesser toes. J Trauma; 50(6):1150—1152. 21. Massari L, Ventre T, Iirillo A (1998) Atypical medial dislocation of the first metatarsophalangeal joint. Foot Ankle Int; 19(9):624—626. 22. Prasad KS(2003) Fracture-dislocation of the first metatarsophalangeal joint. Clark et al. Is this dislocation plantar, Jahss IV dorsal or pathological? Injury; 34(6):472—473. 23. Rapoff AJ, Heiner JP (1999) Avulsion fracture of the great toe: a case report. Foot Ankle Int; 20(5):337—339. 24. Richardson EG (1999) Hallucal sesamoid pain: causes and surgical treatment. J Am Acad Orthop Surg; 7(4):270—278. 25. Sanhudo JAV (2002) Stenosing tenosynovitis of the flexor hallucis longus tendon at the sesamoid area. Foot Ankle Int; 23(9):801—803. 26. Scranton PE Jr (2000) Lower extremity stress fractures. In: M.S. Myerson (ed): Foot and Ankle Disorders. Vol 2. W.B. Saunders, Philadelphia, 1420—1434. 27. Schnaue-Constantouris EM, Birrer RB, Grisafi PJ, et al (2002) Digital foot trauma: emergency diagnosis and treatment. J Emergency Med; 22(2):163—170. 28. Stephenson KA, Beck TL, Richardson EG (1994) Plantar dislocation of the metatarsophalangeal joint: case report. Foot Ankle Int; 15(8):446—449. 29. Thordarson DB (2000) Fractures of the midfoot and forefoot. In: M.S. Myerson (ed): Foot and Ankle Disorders. Vol 2. W.B. Saunders, Philadelphia, 1265—1296.
10. Daly N (1996) Fractures and dislocations of the digits. Clin Podiatr Med Surg; 13(2):309—326. 11. Fabeck LG, Zekhnini C, Farrokh D, et al (2002) Traumatic hallux valgus following rupture of the medial collateral ligament of the first metatarsophalangeal joint: a case report. J Foot Ankle Surg; 41(2):125—128. 12. Garcia Mata S, Hidalgo A, Martinez Grande M (1994) Dorsal dislocation of the first metatarsophalangeal joint. Int Orthop; 18(4):236—239. 13. Good JJ, Weinfeld GD, Yu GV (2001) Fracture-dislocation of the first metatarsophalangeal joint: open reduction through a medial incisional approach. J Foot Ankle Surg; 40(5):311—317. 14. Hennessy MS, Saxby TS (2001) Traumatic “mallet toe” of the hallux: a case report. Foot Ankle Int; 22(12):977—978. 15. Hussain A (1999) Dislocation of the first metatarsophalangeal joint with fracture of fibular sesamoid. A case report. Clin Orthop; 359:209—212. 16. Hynes D, D‘Souza LG, Stephens M (1994) Irreducible dislocation of the fifth metatarsophalangeal joint: a case report. Foot Ankle Int; 15(11):625—626.
Correspondence address Prof. Dr. med. T. Mittlmeier Chairman and Professor of Trauma and Reconstructive Surgery Chirurgische Klinik und Poliklinik der Universität Rostock Abteilung für Unfall- und Wiederherstellungschirurgie Schillingallee 35 18055 Rostock, Germany phone: +49 381 494 6051 fax: +49 381 494 6052 email: [email protected]
Sesamoid and toe fractures Thomas Mittlmeier, Patrick Haar Chirurgische Klinik und Poliklinik der Universität Rostock, Abteilung für Unfall- und Wiederherstellungschirurgie, 18055 Rostock, Germany
KEYWORDS: Toe fracture; crush injury; sesamoid fracture; stress fracture; fracture-dislocation.
Summary1 Injuries of the toes and sesamoids of the first metatarsophalangeal joint comprise a wide spectrum of traumatic entities. Despite the fact that a majority of lesions may well respond to nonsurgical treatment and exhibit an excellent prognosis, appropriate clinical and imaging analysis is mandatory to select those injuries that require specific therapeutic and surgical measures to avoid long-term sequelae of functional disability.
Introduction Fractures of the toes represent the most common fracture of the forefoot, with an incidence of 140 cases per 100,000 population per year and a male: female ratio of 1.6 [3, 27]. While it may be true that the overwhelming majority of phalangeal fractures of the lesser toes does not result in a relevant clinical disability independent of any residual malalignment, the same statement may not be valid for dislocated fractures of the great toe, particularly intraarticular or complex fractures, physeal injuries in children, fracture-dislocation of the first metatarsophalangeal joint or interphalangeal joint dislocation, and chronic overuse injuries as in hallucal sesamoid bone stress fractures [3, 18]. In particular, the last of these injuries may confront the doctor with a variety of differential diagnoses. If the correct diagnosis is missed, incapacitating pain may result [24]. Concomitant morbidity, eg, diabetes mellitus with sensory neuropathy, may be a reason why a toe fracture is not primarily diagnosed, only becoming apparent due to secondary complications. Crush injuries of the forefoot from machine-related (eg, lawnmower injuries) or industrial injuries (eg, dropping of a heavy weight onto the foot) do generally involve the toes and require a profound expertise in management of complex fractures with severe damage of the soft tissue envelope [27]. 1
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Correspondingly, the mechanisms of injury range from low-energy trauma due to indirect forces (eg, a hyperextension injury of the metatarsophalangeal or interphalangeal joint of the hallux, “stubbed toe” or the “bedroom” or “night-walker” fracture of the fifth digit due to abductory forces) to high-energy trauma and direct force impaction following a fall or a motorcycle or motor vehicle accident (eg, leading to a complex dislocation of the first metatarsophalangeal joint [7, 12, 21, 22]). Consequently, as trauma severity increases, the chance of concurrent injuries of the proximal forefoot and midfoot areas increases [7]. Thus, the wide field of injury patterns in the toe area underlines the fact that diagnosis and treatment of injuries at the toe area are not as trivial as it might appear at first glance. In the following sections, the spectrum of acute and chronic injuries in the toe area will be discussed with particular reference to diagnostic and therapeutic options.
Clinical evaluation The history of direct or indirect trauma and the clinical image of the distal forefoot—which is easily accessible to clinical assessment with manifestation of regional pain, hematoma, ecchymosis, tenderness and swelling, deformity, crepitation, pain during active and passive motion and the disability to bear weight and initiate the roll-over process—usually makes it easy to localize the site of injury. Subungual
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hematoma is a hallmark of distal phalangeal fractures [3]. The diagnosis might be rendered more difficult if the initial clinical presentation of trauma is oligosymptomatic as in some physeal injuries of the distal phalanx of a stubbed toe in children, where subungual bleeding may be the only hint of an open injury and later sequelae such as osteomyelitis and growth arrest may develop [10, 18]. In addition, trauma may be overlooked if it is not perceived by patients with systemic metabolic disease (eg, diabetes mellitus) or neurological disorders leading to peripheral somatosensory deficits. Chronic trauma such as stress fractures of the sesamoids also may create differential diagnostic problems as with sesamoiditis, osteochondritis dissecans, avascular necrosis, adventitious bursitis, and tenosynovitis of the flexor hallucis longus [4, 25, 26]. Progressive activity-related pain and swelling underneath the first metatarsal head will lead to the correct working diagnosis. A vibrating tuning fork is a helpful diagnostic tool as it causes local discomfort in patients with a stress fracture [27].
Radiographic examination and imaging techniques Anteriorposterior, medial and lateral oblique views of the forefoot should be evaluated if acute frac-
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tures or chronic problems of the toe area without exact limitation of the trauma or combined injuries are suspected (Fig. 1a, b). The medial oblique view is helpful in assessing the tibial sesamoid, and the lateral oblique view aids evaluation of the lateral sesamoid [24]. Bilateral exposures can be helpful for discriminating between traumatic and non-traumatic issues (Fig. 1c). Focused images are indicated if the injury is well confined or for follow-up reasons [27]. A lateral view of the complete toe area is not very helpful for displaying the single rays since the structures overlap. Strictly lateral views of single rays may be advantageous in certain types of dorso-plantar dislocation. An axial or skyline view of the sesamoids should be performed in those cases where a pathological condition of the sesamoids is assumed (Fig. 2a—c). Fluoroscopy is particularly helpful in merely ligamentous injuries, where stress testing can prove the degree of instability that might be hidden in standard static x-ray views. This technique can also be applied to patients who manifest dislocations or fracture-dislocations of the toes to demonstrate the chance of closed reduction or the corresponding irreducibility necessitating open reduction. Stress sesamoid views can visualize displacement of the sesamoid complex with dorsiflexion of the great toe, which gives an indirect hint at a rupture of the plantar plate if
Fig. 1: (a) Standard x-ray dorsoplantar view of the forefoot. (b) Medial oblique view of the forefoot. (c) Bilateral comparative dorsoplantar view of the forefoot.
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distal migration of the sesamoids with dorsiflexion does not occur. In chronic problems weight-bearing x-rays of both feet usually clearly depict the site of the deformity or instability [11, 19]. Technetium bone scanning may be useful for demonstrating increased activity in stress fractures, particularly if comparing both feet in unilateral problems [5, 27]. However, one has to bear in mind that an increased asymmetric scintigraphic activity may occur in up to 29% of asymptomatic persons [24]. CT and MRI scans including 2-D reconstructions can be particularly indicated for analyzing sesamoid fractures and posttraumatic soft tissue pathology and for differentiating traumatic and non-traumatic conditions (compare Figure 3, (p. 90) [4, 5, 11, 27]).
Fig. 2: (a, b) Apparatus for axial sesamoid view (“skyline view”). (c) Radiographic example of bilateral skyline view.
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Specific injuries Phalangeal fractures Some authors separate hallucal phalangeal fractures from lesser toe fractures by alluding to the larger and functionally more important phalanges of the hallux [29]. Phalangeal fractures generally occur following direct trauma (stubbing injury or crushing injury when an object is dropped on the foot), with the lesser toe fractures being the commonest injuries [3, 29]. Abduction injuries such as the „night-walker fracture“ of the fifth toe, which may occur while ambulating barefoot in the dark, are another typical injury mechanism [10]. Depending on the energy of direct trauma, the nail bed is frequently involved in digital fractures [27]. Inadequate management of nail-bed trauma may lead to nail deformation, malalignment, splitting, or chronic infection [27]. An acute subungual hematoma with a concomitant intact nail should be decompressed, eg, by heating an uncoiled paper clip for perforation of the nail substance. If bleeding from the eponychium and/or laceration of the nail bed is present, open fracture of the distal phalanx should be suspected [18]. An open fracture should be assumed in children if the physis of the distal phalanx is involved, even in absence of the typical clinical signs of bleeding around the nail. The open fracture can be derived from the close vicinity of the skin and the periosteum at the nail root immediately above the corresponding physis [18]. Management according to the principles of open fractures can prevent infection, osseous growth arrest, and disturbance of nail growth [18]. The majority of closed nondisplaced or minimally displaced stable digital fractures can be immobilized by buddy taping to the adjacent digit(s) (Fig. 4).
Fig. 4: Buddy taping of a nondislocated fracture of a hallucal distal phalanx.
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Fig. 3: Differential diagnosis of sesamoid problems. (a, b) Contusion of the sesamoids: negative MRI, subsesamoid bursa. (c, d) Osteonecrosis of the left fibular sesamoid (x-rays). (e) Intact contralateral foot (skyline view). (f, g) Proof of osteonecrosis by MRI.
This technique generally allows for early full weightbearing in a shoe with a wide toe box and a rigid sole. Splinting should be renewed in defined time intervals to guarantee effective immobilization and to prevent such adverse effects as interdigital skin maceration [29]. While three weeks of splinting should be sufficient in children, a period of 4—5 weeks is recommended for adults [27]. Despite displaced phalangeal shaft fractures, particularly of the three central digits, rarely causing clinical disability, even in the presence of manifest malalignment, it does not necessarily mean that closed reduction and immobilization should not be intended primarily [3, 27]. After induction of adequate local or regional anesthesia, longitudinal manual traction and manipulation of the corresponding digit, reverting the mechanism of injury, can re-
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Fig. 5: K-wire fixation of a shaft fracture of the proximal phalanx of the hallux. (a) View after trauma. (b, c) X-rays after ORIF.
store adequate alignment regarding length axis and rotation [27]. Simple reduction aids such as a pencil used as a fulcrum placed in the web space may be helpful for stabilizing the proximal fragment. Even comminuted fractures may successfully be molded into acceptable alignment of the digit [10]. The mode of immobilization, again, depends on the degree of instability after successful reduction, which must be documented by radiography. Transverse diaphyseal fractures represent quite stable fractures after reduction in contrast to oblique, spiral, or comminuted fracture variants, which require analogous techniques of immobilization to nondisplaced fractures. Nevertheless, a decision must be made in those cases where substantial deformity is still present after an attempt at closed reduction or in cases of dislocated joint fractures. Prior to any potentially open procedure, a thorough assessment of the soft tissue status, including the general status of the patient (eg, advanced arterial occlusive disease), is mandatory. On one hand, it is certainly true that limited use of hardware in the phalanges of the foot contributes to the avoidance of implant-related complications, on the other hand, however, painful
angular deformity and posttraumatic degenerative joint disease, particularly of the most medial or lateral digits may be the reason for profound functional disturbance. In the lesser toes, K-wires, cerclages or mini-screws are preferable to any bulky implant. Kwires offer the advantage of stabilization following closed reduction or reduction with minimum tissue dissection (eg, by use of percutaneously placed reduction forceps). However, due to their migration potential, additional immobilization with a cast (Fig. 5) is advisable. Therefore, in joint fractures or spiral or oblique diaphyseal fractures, mini-screws offer a substantially better primary stability (Fig. 6). Despite this fact, some authors state that secondary resection arthroplasty and dermoplasty could be an effective solution [10]. There is less variability in the approach towards a dislocated and/or unstable fracture of the hallux due to its role at push-off during the roll-over process. The importance of the first ray and the stability of the first MTP joint is already appreciated in patients following amputation injuries of the great toe [1]. A dislocated comminuted diaphyseal fracture or a bicondylar epi-/metaphyseal fracture of the proximal
Fig. 6: Screw fixation of shaft and joint fractures. (a, b) X-rays of a dislocated proximal phalanx fracture of the fifth toe. (c, d) X-rays after ORIF. (e, f) Monocondylar fracture of the proximal phalanx of the fourth toe.
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hallucal phalanx is well suited for application of a mini-plate (Fig. 7). Misinterpretation of a bicondylar fracture as a monocondylar tear-off fracture with underdimensioned postoperative stability will invariably lead to redislocation and indicate a revision procedure (Fig. 8). The rare occurrence of an avulsion fracture of the extensor insertion at the distal phalanx of the hallux should follow the same principles that represent the standard for treating a mallet finger [14, 23]. As such, surgery will only be indicated for marked plantar dislocation of the distal phlanx [14]. Open fractures, in particular, from crushing traumas such as in lawnmower injuries, are rarely limited to the toe region. Generally, compound bone-soft tissue injury represents a surgical emergency situation where the standard rules of treatment of complex trauma are to be followed to prevent infection and secondary loss of tissue due to progressive soft tissue damage. Systematic irrigation and radical
Fig. 7: Plate fixation of a comminuted fracture of the proximal phalanx of the hallux. (a) Preoperative view. (b, c) Postoperative x-rays.
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debridement in the operating room should be supplemented by provisional stabilization of fractures, preferably by K-wire transfixation that if necessary
Fig. 8: Misinterpretation of a bicondylar fracture of the proximal hallucal phalanx. (a) Post trauma. (b, c) Inadequate stabilization with two mini-screws. (d, e) Revision technique.
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can be converted into internal fixation at a later stage of tissue consolidation. At the earliest stage of treatment, an imminent or manifest compartment syndrome should be ruled out or detected. At best, prophylactic fasciotomy should be performed. There are rare indications for microvascular repair in the toe area [1], but, even a viable soft tissue flap of an otherwise destroyed toe might be useful for coverage of a forefoot defect. In amputation injuries, conservation of the stump of the proximal phalanx will be helpful for providing a buttress for the adjacent toes to prevent horizontal instability and secondary deformity [10].
Sesamoid fractures The two sesamoids at the first metatarsophalangeal joint level are well embedded in the capsuloligamentous complex (Fig. 9a); the medial (tibial) sesamoid being larger than the lateral (fibular) sesamoid, corresponding to its more important
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role in weight bearing within the medial sulcus of the metatarsal head. They are held together by the strong intersesamoid ligament and the plantar plate, which is firmly attached at the base of the proximal phalanx and loosely fixed at the neck of the metatarsal via the capsule. The sesamoids are enveloped within the two strands of the flexor hallucis brevis muscle. In addition, the abductor hallucis tendon inserts at the medial sesamoid, the adductor hallucis tendon at the fibular sesamoid. Strong collateral ligaments with two essential components, the metatarsophalangeal and metatarsosesamoid ligaments, support the first metatarsophalangeal joint at the medial and lateral side contributing together with the capsule and the extensor elements to an outstandingly high degree of stability of the first metatarsophalangeal joint [8, 24]. While the lateral sesamoid is rarely bipartite, a bipartite sesamoid can be found in 10% of the population. This condition is seen in both feet in 25%, which sometimes makes it difficult to differentiate between a symptomatic bipartite or multipartite
Fig. 9: (a) Normal anatomy of the first MTP joint and classification of dislocations of the MTP I joint. (b) Type IA dislocation. (c) Type IB dislocation. (d) Type IIA dislocation. (e) Type IIB dislocation. (f) Type IIC dislocation.
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sesamoid, a sesamoid fracture, or a fracture through a bipartite sesamoid [24]. Fractures in sesamoids may occur by direct trauma or by repetitive overuse (stress fracture) or during fracture-dislocation of the first metatarsophalangeal joint (see below). Stress fractures are generally found in athletes [4, 5, 24]. The non-characteristic onset of symptoms, with some swelling of the forefoot and exercise-related pain increased during forced dorsiflexion of the great toe, raises the differential diagnoses of sesamoiditis, chondromalacia, flexor hallucis brevis tendinitis, osteochondritis dissecans and avascular necrosis of the sesamoids, arthritis, localized plantar keratosis, and impingement of the medial plantar digital nerve [24, 25]. A thorough clinical examination preferably supplemented by bilateral standard x-rays will be the key to a conclusive diagnosis. The confirmation
Fig. 10: Acute medial sesamoid fracture. (a, b) X-rays of fractured tibial sesamoid. (c, d) Approach and intraoperative view. (e, f) Postoperative x-rays.
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of an unstable sesamoid stress fracture may be the radiographic proof of progressive separation of the fragments over time. With regard to the heterogeneity of fracture etiology and the low incidence of sesamoid fractures, the optimum choice of treatment remains unclear [5]. While initially a conservative treatment based on rest or partial weight bearing, cessation of sports, application of a short-leg walking cast for six weeks, or the supply of a molded orthosis for 6—8 weeks supported by antiphlogistic drugs is recommended by most authors, surgery is generally advised if nonoperative treatment fails [4, 5]. Due to the crucial role of force transmission of the sesamoids total sesamoidectomy without soft tissue reconstruction is rarely recommended. Partial (proximal) sesamoidectomy and reconstruction of the short flexor tendon
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has been shown to represent a reliable option to alleviate pain and allow return to a high level of activity [4]. Other authors have recommended autologous bone grafting in patients with symptomatic nonunion [26]. A minimum invasive technique using plantar percutaneous cannulated screw fixation appears to be such a successful alternative to open procedures for acute fractures, nonunions, and stress fractures that the authors question the importance of diagnosing the specific individual etiology [5]. Total sesamoidectomy should be avoided as it produces a mechanical defect in the flexor hallucis brevis tendon-muscle unit and reduces the flexion movement arm of the muscle at the metatarsophalangeal joint level [2, 24]. Therefore, total sesamoidectomy should only be applied in cases with recalcitrant inflammatory arthritis [24]. Excision of both sesamoids has a high potential of inducing hallux valgus or cock-up deformity of the hallux [24]. The open surgical approach for the tibial sesamoid is preferably a longitudinal low medial or medial plantar approach (Fig. 10) while the fibular sesamoid is exposed via a dorsal incision in the first web space or via a direct plantar approach. The corresponding plantar nerves should be spared. The tendons and capsule should be repaired meticulously [4, 24].
Sprains and dislocations/fracturedislocations A specific injury variant of the first metatarsophalangeal joint is that of a dorsiflexion injury leading to a sprain with and without lesion of the sesamoid complex. Sprains of the first metatarsophalangeal joint represent a common injury, particularly during sports, that is commonly referred to as „turf toe“ [8]. The incidence of this traumatic entity has risen with increasing popularity of artificial sports ground surfaces and the energy necessary to lead to the rare fracture-dislocation variants is substantially higher than the energy necessary to cause a turf toe [7]. Progressive traumatic hyperextension of the first metatarsophalangeal joint leads to a lesion of the plantar capsule at the metatarsal neck being weaker than the attachment at the proximal phalanx. Finally, compression injury at the dorsal articular surface of the metatarsal head can result in maximum hyperextension [8]. Clanton [8] has formulated three degrees of sprain severity characterizing the corresponding pathology at the first metatarsophalangeal joint. While a Degree 1 sprain corresponds to stretching of the capsulo-ligamentous complex with localized plantar medial tenderness and swelling and the preserved
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ability to bear weight, a Degree 2 sprain is characterized by plantar ecchymosis and the inability to perform sports due to a partial tear of the plantar capsulo-ligamentous complex. A Degree 3 sprain is marked by a more complete tear of the capsuloligamentous complex and often includes tearing of the plantar plate from its origin on the metatarsal head junction and an impaction of the proximal phalanx into the metatarsal head dorsally. A sesamoid fracture or a separation of a bipartite sesamoid may be included in this third stage. Sometimes, a distal rupture of the capsulo-ligamentous complex can be concluded from manifest proximal migration of the sesamoid complex. Clinically, the patient with a Degree 3 sprain is unable to bear weight on the medial forefoot with gross restriction of range of motion of the first metatarsophalangeal joint. Surgery is only indicated in the rare cases of sprain where instability, a dislocated sesamoid fracture or a loose osteochondral fragment within the joint space becomes apparent [8]. The overwhelming majority of patients can be treated non-surgically by protection, rest, ice, compression, and elevation (acronym “PRICE”) supplemented by nonsteroidal antiphlogistics. Remobilization of the patient is facilitated by prescribing inserts or recommending the wearing of a stiff-soled shoe. Repetitive trauma may lead to the development of hallux rigidus. In contrast to sprains, first metatarsophalangeal joint dislocations or fracture-dislocations are often associated with concomitant injuries of the midfoot and forefoot [7]. The underlying mechanism of injury is a combination of forefoot hyperextension, axial loading of the foot and midfoot hyperflexion. In 1980, Jahss published a classification comprising three types of complex dislocation of the first metatarsophalangeal joint (I, IIA, IIB) to which three further types (IA/B, IIC, III) have been added over the following years (Fig. 9b—f). In type I dislocations, the strong intersesamoid ligament remains intact. While in type IA dislocations, the hallux dislocates with proximal disruption of the sesamoid complex generally leading to irreducibility by closed means due to interposition of the plantar plate and the sesamoid block (buttonhole effect). Type IB may be overlooked initially as the dislocation with distal disruption of the sesamoid complex at its distal insertion may reduce spontaneously. This might be interpreted as a „sprain“ leading to a consecutive claw-toe deformity and loss of intrinsic strength. Type II dislocations are mostly reducible due to partial disruption of the sesamoid complex (type IIA intersesamoid ligament rupture, type IIB transverse fracture of one of the sesamoids, Fig. 9d, e). Type IIC represents a combination of types IIA and IIB (Fig. 9f). Widening of the
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intersesamoid distance is the common radiographic feature of type II injuries. Jahss has added a type III injury corresponding to a complete rupture of both conjoined tendons with intact sesamoids and plantar plate [13, 15, 22]. As a general recommendation, closed reduction should be attempted first by accentuating the deformity by further dorsiflexion followed by longitudinal traction and plantar flexion of the proximal phalanx [7, 12]. Joint stability and congruity should be assessed post reduction clinically and radiographically [3]. Persistent instability, a crepitation, an interposition of loose bodies in the joint space (widened joint space), and a dislocated sesamoid fracture represent indications for open revision, as in irreducible dislocations /fracture-dislocations. A dorsal or medial approach (particularly when the tibial sesamoid is fractured) is preferable to a plantar approach, which does not guarantee enough exposure of the underlying pathology [3]. Due to the variability and the relative rarity of the
Fig. 11: (a) Normal anatomy of the hallucal interphalangeal joint. (b) Type I dislocation: invagination of the ruptured plantar plate and the sesamoid bone. (c) Type II dislocation with completely displaced plantar plate with hyperextension and shortening deformity.
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trauma entity, no conclusive recommendations can be given regarding repair of the injured structures. Repair of the ruptured intersesamoid ligament is not addressed in the literature [13]. Depending on the site of fracture location and size of fragment(s), some authors prefer partial sesamoidectomy instead of fracture repair, including reconstruction of the residual sesamoid-tendon structures and the capsule [13]. There has been a number of authors presenting different directions of dislocations of the great toe that are even rarer than the types of dorsal dislocation [6, 21]. Principally, the approach towards diagnostics and the algorithm of treatment given for dorsal dislocations can be applied analogously. Dislocations of the lesser metatarsophalangeal joint also represent uncommon injuries [16, 20, 28]. Depending on the direction of dislocation, the interposed tendon of the flexor digitorum longus muscle (latero-dorsal dislocation) or the tendons of the extensor digitorum longus and brevis muscles (plantar dislocation) wrapped around the metatarsal head might represent an obstacle to closed reduction necessitating open revision. In chronic dislocation, the final outcome depends on anatomical reduction and total correction of secondarily contracted soft tissue structures [20]. Interphalangeal joint dislocation affects the first and fifth toes, again, being mostly the result of direct stubbing injury [3]. Two types of irreducible hallucal interphalangeal dislocation exist: the first where the ruptured plantar plate is invaginated into the widened joint space (Fig. 11b) and the second where the plantar plate and an interphalangeal sesamoid, which is present in more than 95% of adults, is dislocated dorsally to the head of the proximal phalanx, leading to a hyperextension deformity (Fig. 11c). A medial approach for irreducible dislocations seems preferable to the dorsal approach, which might expose the extensor apparatus to additional damage [9]. Blunt trauma of the middle phalanx of the fifth toe might resemble the radiographic appearance of a dislocation due to local swelling and hematoma, but may only be a pseudodislocation [27]. In general, fracture-dislocations of the metatarsophalangeal and interphalangeal joints will have a good prognosis if correct reduction and alignment of the joint is achieved; patients with permanent complaints are those with combined trauma (eg, additional Lisfranc joint involvement) or bilateral injuries [7]. Isolated injuries of single structures of the metatarsophalangeal joint (rupture of the adductor tendon, isolated traumatic dislocation of the lateral sesamoid, rupture of the medial collateral ligament) will only lead to long-term problems in exceptional situations [11, 17, 19].
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Conclusion Effective treatment of injuries of the distal forefoot essentially depends on the knowledge of the anatomy and the understanding of the biomechanical function of the involved structures. An under-appreciation of the functional value of the toes and the sesamoids is not justified at all. Adequate clinical assessment and diagnostic imaging offer the key to addressing those injuries properly.
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17. Irwin AS, Maffulli N, Wardlaw D (1995) Traumatic dislocation of the lateral sesamoid of the great toe: nonoperative management. J Orthop Trauma; 9(2):180—182. 18. Kensinger DR, Guille JT, Horn DB, et al (2001) The stubbed great toe: importance of early recognition and treatment of open fractures of the distal phalanx. J Pediatr Orthop; 21(1):31—34. 19. Labovitz JM, Kaczander BI (2000) Traumatic hallux varus repair utilizing a soft-tissue anchor: a case report. J Foot Ankle Surg; 39(2):120—123. 20. Leung WY, Wong SH, Lam JJ, et al (2001) Presentation of a missed injury of a metatarsophalangeal joint dislocation in the lesser toes. J Trauma; 50(6):1150—1152. 21. Massari L, Ventre T, Iirillo A (1998) Atypical medial dislocation of the first metatarsophalangeal joint. Foot Ankle Int; 19(9):624—626. 22. Prasad KS(2003) Fracture-dislocation of the first metatarsophalangeal joint. Clark et al. Is this dislocation plantar, Jahss IV dorsal or pathological? Injury; 34(6):472—473. 23. Rapoff AJ, Heiner JP (1999) Avulsion fracture of the great toe: a case report. Foot Ankle Int; 20(5):337—339. 24. Richardson EG (1999) Hallucal sesamoid pain: causes and surgical treatment. J Am Acad Orthop Surg; 7(4):270—278. 25. Sanhudo JAV (2002) Stenosing tenosynovitis of the flexor hallucis longus tendon at the sesamoid area. Foot Ankle Int; 23(9):801—803. 26. Scranton PE Jr (2000) Lower extremity stress fractures. In: M.S. Myerson (ed): Foot and Ankle Disorders. Vol 2. W.B. Saunders, Philadelphia, 1420—1434. 27. Schnaue-Constantouris EM, Birrer RB, Grisafi PJ, et al (2002) Digital foot trauma: emergency diagnosis and treatment. J Emergency Med; 22(2):163—170. 28. Stephenson KA, Beck TL, Richardson EG (1994) Plantar dislocation of the metatarsophalangeal joint: case report. Foot Ankle Int; 15(8):446—449. 29. Thordarson DB (2000) Fractures of the midfoot and forefoot. In: M.S. Myerson (ed): Foot and Ankle Disorders. Vol 2. W.B. Saunders, Philadelphia, 1265—1296.
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Correspondence address Prof. Dr. med. T. Mittlmeier Chairman and Professor of Trauma and Reconstructive Surgery Chirurgische Klinik und Poliklinik der Universität Rostock Abteilung für Unfall- und Wiederherstellungschirurgie Schillingallee 35 18055 Rostock, Germany phone: +49 381 494 6051 fax: +49 381 494 6052 email: [email protected]