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Early Recognition and Treatment of Carpometacarpal Fractures and Dislocations

Abstract

Carpometacarpal (CMC) injuries can easily be missed in more than half of the cases. Early diagnosis is crucial for treatment. Although the clinical aspect can lead the treating physician to suspect that anything is going wrong, appropriate radiographs, especially in the lateral view, are crucial for the diagnosis. The most common CMC fracture dislocations affects the 4th and 5th joints. Treatment will depend on the type of injury and on the degree of joint involvement. Reduction and fixation are usually required. When only one ray is affected, usually the 5th, closed reduction and fixation with Kirschner wires can be performed. In complex cases, open reduction and fixation are required, with Kirschner wires being the most commonly used materials. After the hardware removal, rehabilitation can be intensified. If an appropriate reduction has been achieved, satisfactory functional and radiological outcomes are expected.

Keywords
carpometacarpal joints/injuries; carpometacarpal joints/pathology; carpometacarpal joints/surgery; joint dislocations; hand bones

Resumo

As lesÕes na região carpometacarpal (CMC) podem passar despercebidas em mais da metade dos casos. O diagnÓstico precoce é determinante para o tratamento. Embora clinicamente o paciente já possa demonstrar que de fato ocorreu a lesão, radiografias apropriadas, principalmente na incidência em perfil, são fundamentais para o diagnÓstico. A lesão mais comum afeta as articulaçÕes de 4° e 5° dedos. O tratamento vai depender do tipo da lesão e o grau de envolvimento das articulaçÕes. Geralmente, é necessária redução e fixação. Quando apenas um raio é acometido, habitualmente o 5°, pode ser feita redução fechada e fixação com fios de Kirschner. Nos casos complexos, faz-se necessária a redução aberta e fixação, sendo os fios de Kirschner os materiais mais comumente usados. ApÓs a retirada dos fios, intensifica–se a reabilitação. Se foi alcançada uma redução apropriada, esperam-se resultados funcionais e radiográficos satisfatÓrios.

Palavras-chave
articulaçÕes carpometacarpais/lesÕes; articulaçÕes carpometacarpais/patologia; articulaçÕes carpometacarpais/cirurgia; luxaçÕes articulares; ossos da mão

Introduction

Although it corresponds to < 1% of hand injuries,11 Steinmetz G, Corning E, Hulse T, et al. Carpometacarpal FractureDislocations: A Retrospective Review of Injury Characteristics and Radiographic Outcomes. Hand (N Y) 2019:1558944719852743 it is not uncommon to doubt whether there is any radiographic alteration in the base of the carpometacarpal (CMC) from the second to the fifth fingers in the routine of attending orthopedic trauma. This is because there is a bone overlap between the CMC and the carpal bones, which may generate some misunderstanding in the interpretation of the images.22 Henderson JJ, Arafa MA. Carpometacarpal dislocation. An easily missed diagnosis. J Bone Joint Surg Br 1987;69(02):212-214 This difficulty can be mitigatdif the clinical evaluation is well done and if the anatomical knowledge is improved.

The joints in the so-called CMC region are, as a rule, rigid, firm, stable, especially in the most radial fingers. Mild trauma is unlikely to lead to major injuries. Therefore, establishing the real mechanism of the accident and performing a good physical examination can be decisive for not neglecting this type of injury. Henderson et al.22 Henderson JJ, Arafa MA. Carpometacarpal dislocation. An easily missed diagnosis. J Bone Joint Surg Br 1987;69(02):212-214 reported diagnostic failure in 15 of 21 patients, relating to 2 main factors: edema, which hinders a more accurate examination, and the lack of a lateral x-ray view.

Thus, if there may be some complexity in the diagnosis, it is to be expected that the treatment also has its drawbacks. And this in fact occurs, because those injured ligaments, with a view to return to the stability they had before the accident, need to be healed in the correct position, that is, with the joints relating perfectly to each other, in order to provide a functional and painless hand.33 Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42

At first, it could be deduced that, since there is no mobility at the base of the second and third CMCs, then any reduction would be acceptable. This is not true, for the simple reason that the center of the hand falls exactly on the third radius, and if it is badly reduced, it may have consequences suchas a decrease in grip strength.44 Talmaç MA, Görgel MA, Dirvar F, Tok O, özdemir HM. Functional and radiological outcomes of multiple dorsal carpometacarpal fracture dislocations treated with open reduction and internal fixation. Eklem Hastalik Cerrahisi 2019;30(02):130-136

The purpose of the present review is to cover pertinent anatomical and functional aspects, which is the state of the art regarding the diagnosis of carpometacarpal fractures and dislocations (⧐Box 1), and to consider the updates regarding different types of treatment.

Box 1 Carpometacarpal Lesions

Patient Profile

  • √ Men, young, trauma involving high-energy impact

  • √ Direct trauma with a clenched fist

Observe at the Clinic

  • √ Edema and fist pain

  • √ Palpate the back of the metacarpal with crackling

  • √ Check alignment of the base of the metacarpal bones and the carpal bones Images

  • √ Hand x-ray: posteroanterior, Metacarpal lateral, Oblique

  • √ Most Common: Dislocation associated with fracture at the base of the metacarpal or carpal bones (hamate)

  • √ Most affected metacarpal structures: 4th and 5th fingers

  • √ Fractures with multiple dislocations are more common than isolated ones

  • √ CT-Scan if there is doubt in the radiographic image Treatment

  • √ Closed reduction and plaster often result in loss of reduction and poor results

  • √ Fracture-dislocation of the 5th CMC isolated with or without hamate fracture: Closed reduction and fixation with transverse K wires, from the 5th to the 4th metacarpal, and if necessary, in the hamate

  • √ Multiple fracture-dislocation of all fingers Open reduction and stabilization with K wires or mini-micro fragment plates and screws Start withthe reduction and alignment of the 3rd CMC

  • √ K wires for 6 weeks on average

  • √ Early guidance for mobilization of interphalangeal and metacarpophalangeal

Anatomy and Kinesiology

There is a considerable difference in anatomical terms between the bases of the different metacarpal bones, and as a result, the range of motion in flexion-extension, although variable, is smaller in the 2nd and 3rd than in the 4th and 5th metacarpals. Gunther55 Gunther SF. The carpometacarpal joints. Orthop Clin North Am 1984;15(02):259-277 showed, in a cadaveric study, that there is no more than one degree of movement in flexionextension at the base of the 2nd CMC, three degrees in the 3rd, eight degrees in the 4th and 15 degrees in the 5th. Harwin et al.66 Harwin SF, Fox JM, Sedlin ED. Volar dislocation of the bases of the second and third metacarpals. A case report. J Bone Joint Surg Am 1975;57(06):849-851 found 25° to 30° for the 5th, 15°for the 4th, and limited movement in the 2nd and 3rd.

There are several ligaments that maintain stability in this region. Nakamura et al.77 Nakamura K, Patterson RM, Viegas SF. The ligament and skeletal anatomy of the second through fifth carpometacarpal joints and adjacent structures. J Hand Surg Am 2001;26(06):1016-1029 stated that in the 2nd CMC there are two dorsal ligaments and one volar, in the 3rd CMC there are four volar and three dorsal ligaments, on the 4th CMC there are one volar and two dorsal ligament, and on the 5th CMC there are one volar and two dorsal ligaments, with different morphological variations between them. This greater number of volar and dorsal ligament structures at the base of the 3rd CMC contributes to the stability of the adjacent CMC joints.

Regarding joints, the same authors reported that between the 4th and 5th CMC, the 2nd CMC and the trapezium, and between the trapezium and the trapezoidwere all simple joints. There was a greater variation in the joints between the 3rd and 4th CMC (5types: double facet of equal size, small facet with double back, small facet double volar, single facet only dorsal, and single large facet), between the 2nd and 3rd MTC (2 types: single facet and double facet), between the capitate and the hamate (3 types: single L-shaped facet, double facet and simple O-shaped facet) and between the trapezoid and the capitate (3 types: volar single facet, double facet and large single facet).

So, briefly, what we have are the bases of the index and middle finger rigid, due to the articulation with the trapezium, trapezoid and third metacarpal, and also by the presence of those dorsal and volar ligaments, in greater number at the base of the 3rd CMC. In addition, there are insertions of the tendons of the flexor carpi radialis and the long and extensor carpi radialis longus and brevis tendon at the bases of these metacarpal bones, which may even contribute to the avulsion of bone fragments. The dynamic stabilizer of the 5th CMC joint is the tendon of the extensor carpi ulnaris, which also contributes to the dorsal deviation in dislocations.33 Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42

Epidemiology and Classification

Dobyns et al.88 Dobyns JH, Linscheid RL, Cooney WP 3rd. Fractures and dislocations of the wrist and hand, then and now. J Hand Surg Am 1983;8 (5 Pt 2):687-690 reported that, among 1,621 studied hand fractures, only 3 corresponded to carpal-metacarpal dislocation fracture.

Steinmetz et al.1 described that among 81 injuries, 23 (28.8%) corresponded to the isolated injury in the CMC region of the 5th, and 37 (45%) were due to the 4th and 5th injuries. In the same study, 87.5% of the cases corresponded to men, with the right hand being affected in 78.8% of the total. Most cases were due to a blow with a closed fist (46.3%), followed by a fall from a height (20%) and a traffic accident (12.5%). Fisher et al.99 Fisher MR, Rogers LF, Hendrix RW. Systematic approach to identifying fourth and fifth carpometacarpal joint dislocations. AJR Am J Roentgenol 1983;140(02):319-324 reported that multiple dislocations occur more frequently than isolated ones. In 50% of the cases there was isolated involvement of the joint between the fifth metacarpal and the hamate, and 25% affected the 2nd metacarpal.

As there are very strong ligament structures, there may be avulsion and impacted fractures concomitantly with carpometacarpal injuries. Dorsal dislocations are more common than volar, since direct trauma tends to force the metacarpal in flexion. Steinmetz et al.11 Steinmetz G, Corning E, Hulse T, et al. Carpometacarpal FractureDislocations: A Retrospective Review of Injury Characteristics and Radiographic Outcomes. Hand (N Y) 2019:1558944719852743 found only one volar dislocation among 165 evaluated cases.

There are several classification systems described.1010 Cain JE Jr, Shepler TR, Wilson MR. Hamatometacarpal fracturedislocation: classification and treatment. J Hand Surg Am 1987;12 (5 Pt 1):762-767

11 Kim JK, Shin SJ. A novel hamatometacarpal fracture-dislocation classification system based on CT scan. Injury 2012;43(07):1112-1117

12 Tay SC, Leow MQH, Tan ES. Use of dorsal buttress plate fixation for ulnar carpometacarpal joint fracture dislocations for early mobilization: outcomes of 11 cases. Musculoskelet Surg 2019;103(01):77-82
-1313 Pundkare GT, Deshpande SS. Proposal for a Radiological Classification System for Carpo-Metacarpal Joint Dislocations with or without Fractures. Malays Orthop J 2018;12(02):42-46 As most injuries affect the ulnar rays, the classifications are more focused on this area and highlight the possible association with hamate fractures. Cain et al.1010 Cain JE Jr, Shepler TR, Wilson MR. Hamatometacarpal fracturedislocation: classification and treatment. J Hand Surg Am 1987;12 (5 Pt 1):762-767 divided them into type 1A (subluxation or dislocation of the5th CMC without hamate fracture), type 1B (dorsal hamate fracture), type 2 (dorsal hamate comminution) and type 3 (coronal hamate fracture). Tay et al.1212 Tay SC, Leow MQH, Tan ES. Use of dorsal buttress plate fixation for ulnar carpometacarpal joint fracture dislocations for early mobilization: outcomes of 11 cases. Musculoskelet Surg 2019;103(01):77-82 stratify the lesions as type 1 those that involve only one ray, type 2 those that affect two rays, but in subtype 2A the fracture ofthe 4th CMC is extra-articular, and in 2B there is dislocation or fracture-dislocation of 4th and 5th, and type 3, those that involve hamate fracture. There is another classification, simpler, cited by Pundkare et al. which covers all injuries, but refers only to the direction of the deviation, whether dorsal (type A), volar (type B) or divergent (type C).1313 Pundkare GT, Deshpande SS. Proposal for a Radiological Classification System for Carpo-Metacarpal Joint Dislocations with or without Fractures. Malays Orthop J 2018;12(02):42-46

Other less frequent injuries are also described. The dislocation of the 2nd and 3rd CMC, volar or dorsal, has been reported in the literature.1414 Silk G, Vetharajan N, Nagata H. Volar dislocation of the second and third carpometacarpal joints - the Lisfranc injury of the hand? Hand Surg Rehabil 2018;37(05):320-323 Zaizi et al.1515 Zaizi A, El Yaacoubi T, El Bahraouy A, et al. Pure divergent dislocation of the index and middle finger carpometacarpal joints: A rare case. Trauma Case Rep 2019;23:100222 published a case of divergent dislocation, in which the 3rd CMC moved to volar, and the 2nd CMC dislocated to the dorsal region. Mane et al.1616 Mane PP, Bhat AK, Acharya A. Post-traumatic wind swept deformity: five volar carpometacarpal dislocations. BMJ Case Rep 2019;12(05):e229561 showed an undiagnosed lesion in a patient who had volar dislocation of the five carpometacarpal joints.

Clinical Investigation

The initial clinical evaluation is extremely important for the identification of thelesion.Attention shouldfirst be paid to the reported history of the trauma mechanism. Usually, the patient narrates a direct impact on the hand, with significant amount of kinetic energy. In themajority of cases, the report is of trauma with a clenchedfist– as in aggressionswith punches –, car ccidents, and falls.Routinely, it shouldalways be asked if therewas a previous accident, as it is not uncommon, dueto an absolute technical failure in the anamnesis, that the doctor only discovers that therewas an old injurywhen he or she tries to obtain the reduction by anymeans, and realizes that it is not possible.22 Henderson JJ, Arafa MA. Carpometacarpal dislocation. An easily missed diagnosis. J Bone Joint Surg Br 1987;69(02):212-214

Physical examination reveals pain, functional impotence and swelling. Pronounced edema hinders dorsal bone palpation and the perception of discontinuity between the base of themetacarpal bones and the distal rowof the carpal bones. If this stage is overcome, that is, if one suspects that something is not satisfactory, the radiographic examination is carried out. Here is perhaps themainmoment when an errormay occur, as identifying the change, especially in the ulnar fingers, is difficult. More than half of the injuries in this region can go unnoticed in a first visit, inwhich the focus of attention is often diverted due to the existence of other injuries that have a greater impact on the life support of the patients.1717 Potini VC, Gibson PD, Wu K, Li K, Tan V. A Novel Screening Technique for Ulnar-Sided Carpometacarpal Dislocations. Orthopedics 2017;40(02):e352-e356

The Images

The radiographic anatomy of the CMC region seems, at first glance, simple to understand. Fromthe second to the fifth, the articulationwiththe trapezium, the trapezoid, the capitate and the hamate occurs. However, as the lines overlap in the twodimensional image, it is not always possible to detect, immediately, that therewasaninjury, especially inthose caseswhere there is isolatedinvolvement inanyof the rays, suchas thefifth. Fisher et al.99 Fisher MR, Rogers LF, Hendrix RW. Systematic approach to identifying fourth and fifth carpometacarpal joint dislocations. AJR Am J Roentgenol 1983;140(02):319-324 described the parallelism that must exist in the articular surfaces of thesecondrowof the carpus(►►Figure 1). On the posteroanterior (PA) view, if an absence of this congruence is already identified, the lesion should already be suspected.

Fig. 1
Radiograph of the front of the normal wrist region, showing the parallelism between the articular surfaces.

Furthermore, attention should be paid to the lines of the metacarpal cascade in PA view, as described by Hodgson et al.1818 Hodgson PD, Shewring DJ. The ‘metacarpal cascade lines’; use in the diagnosis of dislocations of the carpometacarpal joints. J Hand Surg Eur Vol 2007;32(03):277-281 These authors reported that the lines of the central axis of each metacarpal converge to a common point, located about two centimeters proximal to the articular surface of the radius. If any of the metacarpals presents either a subluxation or a dislocation, then there will be no convergence of all rays.

One of the points thatmay be the cause of misinterpretation of thelesions is the routine request for radiography of the hand in the frontal and obliqueprojections. As the patient reports trauma to the hand, the initial impulse is for the doctor not to pay attention to the lateral view, and to be satisfied only with these two projections. This way, if you are not familiar with the radiographic anatomy of the wrist seen from the front, you may miss an injury at the base of the metacarpal bones. Hence the need for at least lateral incidence.1919 Gaheer RS, Ferdinand RD. Fracture dislocation of carpometacarpal joints: a missed injury. Orthopedics 2011;34(05):399 In this view, it is also possible to evaluate the intermetacarpal angle, as described by McDonald et al.2020 McDonald LS, Shupe PG, Hammel N, Kroonen LT. The intermetacarpal angle screening test for ulnar-sided carpometacarpal fracture-dislocations. J Hand Surg Am 2012;37(09):1839-1844 These authors demonstrated that, in metacarpal lesions on the ulnar side of the carpus, thediaphyseal angles between the 2nd and 5th metacarpals and between the 3rd and 5th metacarpals are generally > 10°; but emphasized that for these cases there is an indication for advanced imaging exams.

In addition to these projections, there are other possibilities. Lefere et al.2121 Lefere M, Dallaudière B, Omoumi P, Cyteval C, Larbi A. Rare carpometacarpal dislocations. Orthop Traumatol Surg Res 2016; 102(06):813-816 when describing a systematization for radiographic analysisof the wrist, recommended requesting PA, lateral and oblique views. In PA, they remind us that the carpal arches must be aligned and there is no overlapping of joint surfaces. In the suspicions of CMC involvement, the oblique ones would serve to analyze the dislocations in more detail. The lateral view would be intended to assess the radiosemilunar-third metacarpal alignment.

Requesting computed tomography (CT) can be an option to clear up doubtful cases, in which the association between trauma mechanism, careful physical examination and clear radiographs in appropriate views are not enough to point out the diagnosis or even outline whether there are joint bone fragments. Steinmetz et al.11 Steinmetz G, Corning E, Hulse T, et al. Carpometacarpal FractureDislocations: A Retrospective Review of Injury Characteristics and Radiographic Outcomes. Hand (N Y) 2019:1558944719852743 in their analysis of 80 patients with this type of injury reported that there was no need for this type of examination. In contrast, Talmaçet al.44 Talmaç MA, Görgel MA, Dirvar F, Tok O, özdemir HM. Functional and radiological outcomes of multiple dorsal carpometacarpal fracture dislocations treated with open reduction and internal fixation. Eklem Hastalik Cerrahisi 2019;30(02):130-136 used the test for all 14 patients evaluated.

Treatment

The main objective of any therapy is to restore hand function without pain, preventing post-traumatic joint degeneration. The treatment of carpometacarpal lesions will depend on a series of elements, such as affected area and structures, degree of displacement, patient activity, and there is no uniform treatment algorithm, mainly due to the low frequency of this type of trauma.33 Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42 The accepted therapeutic modality varies from intramedullary or transverse fixation with Kirschner (K) wires to fixing with back support plates.1212 Tay SC, Leow MQH, Tan ES. Use of dorsal buttress plate fixation for ulnar carpometacarpal joint fracture dislocations for early mobilization: outcomes of 11 cases. Musculoskelet Surg 2019;103(01):77-82,2222 Iwata N, Komura S, Hirakawa A, et al. Dorsal buttress platefixation for the treatment of fracture-dislocation of the fifth carpometacarpaljoint with avulsion fracture of the hamate: a case report. Arch Orthop Trauma Surg 2019;139(01):135-139 A study compared plate and screws with K-wires fixation, concluding that fixation with wires is the gold standard for the treatment of fourth and fifth metacarpal lesions.2323 Bao B, Zhu H, Zheng X. Plate versus Kirschner wire fixation in treatment of fourth and fifth carpometacarpal fracture-dislocations: A retrospective cohort study. Int J Surg 2018;52:293-296 Arthroscopy has also been described as an auxiliary method.2424 Slutsky DJ. Arthroscopic reduction and percutaneous fixation of fifth carpometacarpal fracture dislocations. Hand Clin 2011;27 (03):361-367

In isolated dislocations, eligible to closed reduction, stabilization with transverse wires supported by the uninjured metacarpal may be sufficient to provide stabilization and appropriate treatment.2525 Slocum AMY, Lui TH. Isolated first carpometacarpal joint dislocation managed with closed reduction and splinting. BMJ Case Rep 2019;12(03):e228715 However, Cobb et al.2626 Cobb WA, Dingle L, ZarbAdami R, Rodrigues J. Management of fracture-dislocations of the little finger carpometacarpal joint: a systematic review. J Hand Surg Eur Vol 2018;43(05):530-538 in a systematic review, stated that the clinical evidence is scarce to let us conclude which is the best treatment method for fracturesdislocations of the 5th CMC. Nevertheless, there are alternatives to fixation with K-wires. Nishimura et al. treated 10 patients, who presented dislocations of metacarpal ulnar rays associated with comminuted fracture of the base, using an external fixator, infering that all patients returned to the level of function they had before the accident.2727 Nishimura R, Wright L, Seitz WH Jr. Augmented External Fixation of Ulnar Carpometacarpal Joint Fracture Dislocations. Tech Hand Up Extrem Surg 2019;23(02):84-87

In cases of multiple injuries, open surgery and fixation are indicated, given the difficulty of obtaining adequate closed reduction due to the interposition of soft tissues.33 Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42 In these dislocations that involve from the 2nd to the 5th MTC, the key to the reduction is the 3rd MTC next to the capitate.44 Talmaç MA, Görgel MA, Dirvar F, Tok O, özdemir HM. Functional and radiological outcomes of multiple dorsal carpometacarpal fracture dislocations treated with open reduction and internal fixation. Eklem Hastalik Cerrahisi 2019;30(02):130-136 As it is in the center, if it is not appropriated reduced, it will make all the others remain in an inadequate position.

There is no consensus on the best treatment for these multiple injuries. In the literature, there are descriptions ranging from closed reduction with plaster cast immobilization to arthrodesis.2828 Hanel DP. Primary fusion of fracture dislocations of central carpometacarpal joints. Clin Orthop Relat Res 1996;(327):85-93 However, the tendency of plastered immobilization after closed reduction is to result in subluxation, mainly due to ligamentous interposition.2929 Hartwig RH, Louis DS. Multiple carpometacarpal dislocations. A review of four cases. J Bone Joint Surg Am 1979;61(6A):906-908,3030 Na KT, Lee SU, Joo SY, Nho JY. Concurrent Index-to-Little Finger Dorsal Dislocations of the Carpometacarpal Joints with Carpal Bone Fractures. Indian J Orthop 2019;53(02):374-376 Therefore, as mentioned, open reduction is recommended for cases of multiple dislocations, asthis reduces the risk of compartment syndrome and inadequate reduction.33 Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42,44 Talmaç MA, Görgel MA, Dirvar F, Tok O, özdemir HM. Functional and radiological outcomes of multiple dorsal carpometacarpal fracture dislocations treated with open reduction and internal fixation. Eklem Hastalik Cerrahisi 2019;30(02):130-136

When there is a fracture in the carpus, it may be that the reduction becomes more difficult. For example, the hamate, when fractured, can hinder joint alignment, thus requiring an open reduction and more attention. This is possible through a longitudinal access, identifying vessels and mainly isolating the sensory branches of the radial nerve and the dorsal ones. The tendons are moved away, the capsule is exposed, and its opening is performed, leaving theedges planned for later closure. Next, lesions are identified, and reduction and fixation are performed.

Sometimes, the initial treatment carried out may not have been satisfactory, and a review may be necessary. In ►Figure 2, we can see the sequence of a multiple volar dislocation, the initial fixation that proved to be inadequate, and the fracture revision, with the correct reduction and fixation with multiple K-wires.

Fig. 2
Volar dislocation from 2nd to 5th carpometacarpal. A and B initial radiographs, showing the volar lesion; C and D showing the first treatment, in which the articular incongruity is perceived, both in the PA and in the lateral view; C and D show the correct joint correlation.

Once the surgical procedure is completed, a splint is maintained that can be removed for cleaning around the K-wires. Weekly radiographs are taken to check the maintenance of the reduction. The patient is advised to keep the hand elevated to reduce edema and encouraged to move the fingers, as soon as pain allows. This early rehabilitation favors long-term recovery, especially of the metacarpophalangeal joints. After the removal of the hardware, at approximately 6 weeks, the rehabilitation is intensified. As the range of motion improves, the patient is stimulated to hold objects, initially of light weight, progressing as the grip strength gradually returns.

Complications can occur, most of the time due to the severity of the trauma or the delay in starting treatment.Depending on the location, the patient may show up a few weeks after the accident, and this makes therapy difficult. In other cases, the diagnostic failure may be responsible for the delay. Concomitant injuries, such as ulnar nerve damage, can also be liable for poor results. Inadequate fixation can lead to loss of reduction, and the need for further surgery. Infection can result in joint degeneration. Anyway, cases of treatment failure can culminate in post-traumatic osteoarthritis, in which casean arthrodesis would be necessary in the future.33 Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42 In cases of chronic symptomatic lesions of the base of the 5th CMC, an alternative is to perform the Dubert technique, in which a resection of the base of the metacarpal is performed, associated with the creation of a synostosis next to the 4th CMC.3131 Meraghni N, Bacle G, Marteau E, Bouju Y, Laulan J. Results of the Dubert procedure for chronic painful fracture-dislocations of the fifth carpometacarpal joint. A report of 6 cases. Hand Surg Rehabil 2017;36(05):373-377 To avoid such complications, once a diagnosis of carpometacarpal fractures or dislocations is made, early reduction, adequate stabilization and rehabilitation as soon as possible should be implemented.

Care Systematization

As a routine and systematization of approach to carpometacarpal injuries, the following can be established. Initially, in traumatic injuries, the appendicular skeleton should always be examined in order to avoid injuries that may go unnoticed, especially in unconscious patients. Once ectoscopic changes in the hand have been identified, palpation may reveal crackling. Confirmation takes place with the radiograph, and attention should be paid to the lateral view, in which the alignment of the 3rd CMC is observed. Computed tomography may be requested, especially in cases of diagnostic doubts or to determine the extent of joint involvement. If there is an isolated lesion, closed reduction and fixation with K-wires to the adjacent intact metacarpal is possible.In multiple lesions, open reduction allows a better visualization of joint congruence.

In our experience, the results are no longer satisfactory when the lesion is not recognized in the first stage, or if the reduction is not obtained in full, there is remaining subluxation or dislocation of one ormoremetacarpal bones. To prevent this from occurring, fluoroscopic images must assess multiple planes, driving special attention to the lateral view. Another aspect that weakens the results is the difficulty for rehabilitation, as the patient should be encouraged to move the fingers as soon as the edema recedes, and the pain allows it. Delaying the start of the movements can lead to stiffness of the joints. Also, the cases in which the postoperative immobilization was inadequate, due to the difficulty in obtaining flexion of the metacarpophalangeal joints,keeping them extended, will bring future problems for the hand grip function.

Final Considerations

Carpometacarpal lesions may go unnoticed, notably if due attention is not paid to the trauma mechanism and if the radiographic evaluation is not accurate. Articular anatomy must be known so that prompt diagnosis can be made. Lateral radiographic view may be the key for detecting these injuries. Once diagnosed, the CMC lesion should be treated as soon as the conditions are met. Isolated lesions can be managed with percutaneous fixation, anchoring the affected metacarpal in the adjacent intact one. Multiple injuries usually require open reduction and fixation. The most used synthesis material, with goodresults, is the Kwire, and postoperative immobilization should be performed with flexed metacarpophalangeal joint and interphalangeal joints in extension. Sincethe beginning of the postsurgical period, the patient is encouraged to move the fingers. After removing the K-wires, rehabilitation is intensified. If a good reduction has been achieved, it is expected that the patient will regain strength and function of the hand, without pain. Otherwise, degenerative changes may appear, which will require new interventions in the future, such as arthrodesis.

References

  • 1
    Steinmetz G, Corning E, Hulse T, et al. Carpometacarpal FractureDislocations: A Retrospective Review of Injury Characteristics and Radiographic Outcomes. Hand (N Y) 2019:1558944719852743
  • 2
    Henderson JJ, Arafa MA. Carpometacarpal dislocation. An easily missed diagnosis. J Bone Joint Surg Br 1987;69(02):212-214
  • 3
    Büren C, Gehrmann S, Kaufmann R, Windolf J, Lögters T. Management algorithm for index through small finger carpometacarpal fracture dislocations. Eur J Trauma EmergSurg 2016;42(01):37-42
  • 4
    Talmaç MA, Görgel MA, Dirvar F, Tok O, özdemir HM. Functional and radiological outcomes of multiple dorsal carpometacarpal fracture dislocations treated with open reduction and internal fixation. Eklem Hastalik Cerrahisi 2019;30(02):130-136
  • 5
    Gunther SF. The carpometacarpal joints. Orthop Clin North Am 1984;15(02):259-277
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Publication Dates

  • Publication in this collection
    17 Dec 2021
  • Date of issue
    Nov-Dec 2021

History

  • Received
    12 Aug 2019
  • Accepted
    20 Feb 2020
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