Chapter 13 SCAPHO-CAPITATE FRACTURE-DISLOCATION

Transcription

1 Apergis/ Articular injury of the wrist/ Chapter 13 Chapter 13 SCAPHO-CAPITATE FRACTURE-DISLOCATION EMMANUEL APERGIS M.D, PhD Director at Red Cross Hospital, Athens, Greece

2 Apergis/ Articular injury of the wrist/ Chapter 13 1 INTRODUCTION The combined fractures of scaphoid and capitate, are erroneously characterized as scaphocapitate syndrome, which is however only one manifestation of a wide spectrum of injuries. The term scaphocapitate syndrome refers to associated fractures of the scaphoid and capitate with rotation of the head of the capitate by 90o 180o. The first references regarding a combination of scaphoid and capitate fractures in the context of a greater arc injury were made by Lorie and Perves in However, the term naviculocapitate fracture syndrome was introduced by Fenton 1 in 1956, who described two patients with concomitant fractures of the scaphoid and capitate, where the proximal capitate fragment was rotated by 180 o but their wrists were reduced. Since then, Hamdi 2 in 2012 and Inal 3 in 2009 after reviewing the literature, reported 43 and 47 cases of Fenton s syndrome respectively. INCIDENCE The frequency of the scaphocapitate syndrome is not clearly known. Rand et al 4 reported that capitate fractures accounted for 1.3% of all carpal fractures; 0.3% were isolated capitate fractures, 0.6% were of scaphocapitate syndrome type and 0.4% were fractures of the capitate in association with perilunate fracture dislocation (PLFD) type of injuries. Hertzberg et al 5 reported that in the trans-scaphoid PLFD group, the most frequent variant was the trans-scaphoid, transcapitate type constituting 8% of all PLFD injuries. In our series, from 53 cases of trans-scaphoid PLFD we found 10 cases of associated fractures of the scaphoid and capitate (5 with the wrist dislocated and 5 in the form of scaphocapitate syndrome). In addition, one out of 15 cases of PLFD with intact scaphoid, exhibited with a fracture of the capitate neck and rupture of the STT and lunotriquetral ligaments. MECHANISM OF INJURY Fenton 1 assumed that during a fall with the hand in dorsiflexion and radial deviation, the pointed radial styloid process (the chisel) impinges on the waist of the scaphoid, which is supported by the sturdy capitate (the anvil). When the force is moderately strong, the scaphoid alone will fracture, but when the blow is particularly sharp and violent, the capitate will also fracture. Although a direct blow to the dorsum of the volar-flexed wrist has been implicated, most authors agree with the mechanism proposed by Stein and Siegel 6 based on anatomical studies on cadaver wrists, according to which the patient falls on the outstretched hand and the wrist goes into marked dorsiflexion. The capitate fracture is caused by the impaction of the capitate neck to the dorsal lip of the radius, while the scaphoid fracture is caused by the tension created at the midcarpal joint level by the forced extension. We can reasonably assume that capitate fracture

3 Apergis/ Articular injury of the wrist/ Chapter 13 2 chronically precedes the scaphoid fracture. Rotation of the proximal fragment appears to occur secondarily, forced by the distal fragment, as this returns to neutral position. SPECTRUM OF INJURIES - CLASSIFICATION The spectrum of injuries associated with fracture of the capitate neck is broad, ranging from an isolated, undisplaced fracture to a fracture of the capitate neck in the context of a fully developed greater arc injury (transscaphoid, transcapitate, transhamate, transtriquetral fracturedislocation). There is some confusion in the literature regarding the terminology due to the diversity in the appearance of these injuries. Any misunderstanding could be addressed, if we agreed that the term scaphocapitate syndrome should only be used in cases of a reduced wrist, with concomitant fractures of the scaphoid and the neck of the capitate and with its proximal pole rotated by The two, most common presentations with which a fracture of the capitate neck is manifested, are: a classic scaphocapitate syndrome (Fig.13.1 a, b) and a combination of scaphoid and capitate fractures accompanying a dorsal perilunate dislocation (Fig.13.2 a, b). Some authors believe that the scaphocapitate syndrome constitutes the final stage of a greater arc injury 8, 9. The injury is considered to be a trans-scaphoid, trans- capitate perilunate injury, which appears with the wrist being dislocated or reduced, spontaneously or after closed reduction. The wrist can be reduced but the capitate head remains displaced, with its proximal pole rotated by degrees. Rarely, the combination of scaphoid and capitate fractures is encountered in cases of volar perilunate dislocations, while when the lunate is dislocated, the injury is more extensive 8. Although the combination of capitate and scaphoid fractures is the most frequent, there have been reports, where the fractures of the scaphoid and capitate were associated with fractures of the distal radius 3, the lunate 9, the triquetrum 10, 11 or the hamate 12. In few cases of scaphocapitate fractures, the proximal capitate fragment was volarly displaced causing median nerve compression 13, 4. In rare cases, fractures of the capitate instead of the scaphoid were associated with fractures of the triquetrum 14 or the hamate. The head of the capitate deprived of ligamentous attachments displays a wide range of displacements after a fracture through its neck. If this is justified in combined injuries, it s hardly vindicated in isolated fractures, where the capitate is well protected from injury by its central location within the wrist. Hence, even in isolated fractures, the proximal fragment has been reported to be inverted by 180 o, remaining in the concavity of the lunate 15, or displaced dorsally 7 or volarly with various degrees of rotation.

4 Apergis/ Articular injury of the wrist/ Chapter 13 3 The seemingly isolated but displaced fracture of the neck of the capitate requires scrupulous evaluation to exclude any osseous or ligamentous injuries on the radial and/or ulnar side of the wrist, which are not detectable by simple x-rays 15, e.g. subtle fractures of the distal scaphoid (Fig.1a, b) or ruptures of the scapho-trapezium-trapezoid 16 and/or lunotriquetral ligament. The great variety of displacements of the head of the capitate is observed in cases where the fracture line is located at the level of the head or neck of the capitate. However, when the fracture line is located more distally, comprising the body of the capitate (i.e. distal to the attachment of the scaphocapitate ligament), then the proximal fragment of the capitate may be displaced in association with the distal scaphoid in the same direction, as in the case presented by Kim et al 8. Vance et al 13 stated that there are two common and three uncommon patterns of injury. The first two appear with the same incidence: a) as classic scaphocapitate syndrome, b) as a dorsal perilunate dislocation with the proximal capitate fragment inverted in the concavity of the lunate or dorsally dislocated, c) as a volar perilunate dislocation with the proximal capitate inverted, d) as an isolated volar dislocation of the proximal capitate and e) as an isolated dorsal dislocation of the proximal capitate. Patients with preexisting nonunion of the scaphoid are vulnerable to dorsiflexion injuries, since the protective role of the scaphoid is omitted and the force is directly applied to the neck of the capitate from the dorsal radial rim. Careful assessment of the relationship of the radius to the lunate, the fractured proximal fragment of the capitate and the distal capitate presenting the distal carpal row on the lateral x- ray projection, should allow proper identification of the pattern in each case 13. Assuming the capitate fracture as the main injury, two factors must be evaluated: firstly, the possible coexistence of carpal bone fractures based on the posteroanterior X-ray view and secondly, the possible displacement of the distal capitate fragment, the proximal capitate and the lunate, based on the lateral x-ray view. After specifying these two factors, the following radiologic classification is proposed (Fig 13.3 a, b): 1- According to the fractured bones (P-A view), as: a) Type I: Isolated fractures of the capitate. b) Type II: Combined fractures of the scaphoid and capitate. c) Type III: The combination of a scaphocapitate fracture with other carpal bones (radius, lunate, triquetrum, hamate). d) Type IV: Fracture of the capitate associated with fracture of other carpal bones excluding the scaphoid (hamate or triquetrum).

5 Apergis/ Articular injury of the wrist/ Chapter According to the displacement (L view): a) Of the distal capitate, which could be in alignment with the distal radius (reduced), or displaced dorsally or volarly. b) Of the proximal capitate fragment, which could be undisplaced, displaced or malrotated, inverted within the concavity of the distal lunate and dorsally or volarly displaced with various degrees of rotation, and c) Of the lunate, which could be reduced, volarly or dorsally dislocated. DIAGNOSIS In acute injuries, physical examination reveals significant pain, swelling and restricted motion, while in neglected cases persistent pain and decreased wrist function usually force the patient to seek medical help. Careful neurological examination is required for this complex injury, since median nerve compression is not unusual. Diagnosis is based on cautious radiographic evaluation but the true extent of injury can easily be missed. The injury is often misdiagnosed as a simple scaphoid fracture, while the capitate fracture is often overlooked. A posteroanterior traction radiograph is useful, since the squaredoff end of the proximal capitate is easily seen in this view. In dubious cases, CT scan or MRI were found to be helpful for achieving the correct diagnosis Several reports of delayed diagnosis of this injury pattern have been issued 9, 17. In nearly onethird of 25 cases reported from 1937 until 1993, there was a delay in diagnosis of more than 15 days 9. From 1993 to 2009, 22 cases of scaphocapitate syndrome were reported in the literature with an average delay in diagnosis of 6 days 3, 9. Delayed diagnosis and treatment may result in nonunions, arthritis or carpal collapse and furthermore increases the risk of avascular necrosis of the proximal fragments of the fractured bones. MANAGEMENT Early reports recommended the excision of the head of the capitate since avascular necrosis and nonunion were considered inevitable. Conservative treatment may lead to good results in undisplaced concomitant fractures of the scaphoid and capitate. Most authors 2, 7, 8 agree that regardless of the radiographic appearance of the injury, open reduction and internal fixation is the treatment of choice. In cases of greater arc injuries, the combined approach is recommended, while in pure scaphocapitate syndrome cases the dorsal approach is usually sufficient. Any associated injuries, must be sought. The capitate fragment is usually devoid of any soft tissues and is reduced relatively easy with manual pressure, by applying traction to the hand. K-wires or headless screws may be placed from the proximal to the distal side and have been equally successful for the fixation of the scaphoid and

6 Apergis/ Articular injury of the wrist/ Chapter 13 5 capitate. Reduction and fixation of the capitate must precede that of the scaphoid, otherwise the reduction of the latter is extremely difficult. In cases treated earlier than, for example, two months post-injury and regardless of the displacement of the proximal capitate fragment, open reduction and fixation is justified. No signs of avascular necrosis of the proximal capitate were reported in cases with significant displacement, treated after 2 months postinjury 17 or in an exceptional situation, where the proximal capitate fragment fell on the floor, was washed and put back in place 18. Postoperatively, transient avascular changes of the proximal capitate are frequently seen, but the union of the fracture generally remains unaffected. Kohut et al 11 reported that in 3 out of 6 patients with trans-scaphoid, trans-capitate PLFD, the first dorsal intermetacarpal artery and vein were implanted into the fractured proximal pole of the capitate to assist revascularization, despite the fact that all of them were treated during the first 12 days from injury. The fractured capitate united in all six cases and in one case the density of the proximal pole of the capitate increased temporarily. When the capitate or the scaphoid fracture is comminuted or if the treatment is applied belatedly, primary bone grafting is indicated. In cases of symptomatic osteonecrosis of the capitate head or severe damage of the articular cartilage, the excision of the fragment and a partial fusion (lunocapitate or scapholunocapitate) with autologous bone grafting are indicated. For injuries diagnosed late, i.e. after two months, the management depends on the patients symptoms. As long as the scaphoid fracture has already or is about to unite, the best solution is possibly patient monitoring, since some of them remain asymptomatic or with well tolerated symptoms for many years, despite the malposition of the capitate head. On the contrary, symptomatic patients with bone malalignment probably require some type of midcarpal fusion. In chronic and selected cases, a pyrocarbon capitate resurfacing prosthesis has been used 19. We treated 11 patients with scapho-capitate fracture with open reduction and internal fixation (2 cases with isolated fracture of the capitate were excluded). Six patients were considered as scaphocapitate syndrome and were treated with an average delay of 10.8 weeks (range, 1-32 weeks), while five patients belonged to the PLFD type of injuries and were treated on the day of injury. Three out of six patients with scaphocapitate syndrome were treated with significant delay: 3, 4.5 and 8 months post-injury. None of them showed signs of avascular necrosis preoperatively. The patient treated with 3 months delay, developed avascular necrosis soon after surgery and was subsequently treated with radioscapholunate fusion. For the patient treated with 4.5 months delay, the inverted proximal capitate fragment was reduced, fixated with K-wires and

7 Apergis/ Articular injury of the wrist/ Chapter 13 6 after a follow-up of 2 years, exhibited a good functional result without signs of avascular necrosis. Finally, the patient treated with 8 months delay, underwent lunocapitate fusion. COMPLICATIONS Nonunion, avascular necrosis and the development of arthritis in the long-term are potential complications regardless of the applied method of treatment 4. Early open, anatomical reduction and stable fixation are prerequisites to minimize the above complications. The capitate is at particular risk for avascular necrosis, because its proximal pole is entirely intra-articular and its vascularity is supplied in a retrograde fashion depending on distal toproximal flow across the capitate waist analogous to the blood supply of the proximal scaphoid. The more proximal the fracture of the capitate, the greater the risk for avascular necrosis. The latter has been infrequently reported in isolated capitate fractures but is more common in higherenergy fractures, particularly when the proximal capitate is rotated. The true incidence of capitate nonunion in cases with scaphocapitate syndrome is not known, but it is known that the most substantial and under-recognized complication of isolated capitate fractures is that of nonunion, the incidence of which ranges between % 7. Nonunion of the capitate may be related to both vascular and mechanical factors and is usually associated with absorption of the fracture surfaces and shortening of the capitate 4, 20. This shortening induces carpal collapse and overloading to the scaphotrapezial-trapezoidal and triquetro- hamate joints, on either side. In cases of capitate shortening, the fragments should be distracted to accept an intercalary graft, regain the lost length and restore carpal stability. Rand et al 4, reported 13 cases of fractures, three of which were isolated and two of which progressed to nonunion after non-operative treatment. Rico et al 20 stated that although isolated capitate fractures were less frequent, the incidence of nonunion was greater than in fractures of the capitate associated with other injuries. Reviewing the literature they found 10 cases of capitate nonunion. Rand et al 4 reported that the incidence of post-traumatic arthritis in patients with scaphocapitate syndrome reached 66%. Kohut et al 11 treated 6 patients with greater arc injuries and capitate fractures, with open reduction and K-wires fixation. After a follow-up of 6.4 years all wrists showed mild or moderate (one patient) arthritic changes. Only one patient was entirely free of pain, whereas the others experienced some discomfort or pain at various activity levels.

8 Apergis/ Articular injury of the wrist/ Chapter 13 7 REFERENCES 1. Fenton RL The naviculo-capitate fracture syndrome. J Bone Joint Surg Am 1956; 38: Hamdi M. The scaphocapitate fracture syndrome: report of a case and a review of the literature. Musculoskelet Surg 2012; 96: Inal S, Celikyay F, Turan SM, Atik A, Demir AO, Topuzlar M. An Anusual Varıety Of Sımultaneous Fracture Pattern. Fracture of radius (Colles) with scaphoideum and capitatum. The Internet Journal of Orthopedic Surgery. 2009;Vol 14 Number 1. DOI: /142b 4. Rand JA, Linscheid RL, Dobyns JH Capitate fractures: a long-term follow-up. Clin Orthop 1982; 165: Herzberg G, Comtet JJ, Linscheid RL, Amadio PC, Cooney WP, Stalder J. Perilunate dislocations and fracture dislocations: A multicenter study. J Hand Surg [Am] 1993;18: Stein F, Siegel MW. Naviculocapitate fracture syndrome; A case report. J Bone Joint Surg Am 1969; 51: Sabat D, Arora S, Dhal A. Isolated capitate fracture with dorsal dislocation of proximal pole: a case report. Hand 2011; 6: Kim YS, Lee HM, Kim JP. The scaphocapitate fracture syndrome: a case report and literature analysis. Eur J Orthop Surg Traumatol 2013; Feb 7. [Epub ahead of print]. DOI /s Milliez PY, Dallaserra M, Thomine JM. An unusual variety of scapho-capitate syndrome. J Hand Surg [Br] 1993; 18: Garg B, Goyal T, Kotwal PP. Triple jeopardy: transscaphoid, transcapitate, transtriquetral, perilunate fracture dislocation. J Orthopaed Traumatol 2012 ;Apr 4. [Epub ahead of print] DOI /s x 11. Kohut G, Smith A, Giudici M, Buchler U. Greater arc injuries of the wrist treated by internal and external fixation-six cases with mid-term follow-up. Hand Surg 1996; 1:2: Sabat D, Dabas V, Suri T, Wangchuk T, Sural S, Dhal A. TransScaphoid, Transcapitate, Transhamate fracture of the wrist. J Hand Surg [Am] 2010; 35:7: Vance RM, Gelberman RH, Evans EF. Scaphocapitate fractures. Patterns of dislocation, mechanisms of injury, and preliminary results of treatment. J Bone Joint Surg Am 1980; 62: Thomsen NOB. A dorsally displaced capitate neck fracture combined with a transverse

9 Apergis/ Articular injury of the wrist/ Chapter 13 8 shear fracture of the triquetrum. J Hand Surg Eur published online 28 May 2012; DOI: / Robbins MM, Nemade AB, Chen TB, Epstein RE. Scapho-capitate syndrome variant: 180 degree rotation of the proximal capitate fragment without identifiable scaphoid fracture. Radiology Case reports 2008; 3:3:1-5. DOI: /rcr.2008.v3i Chantelot C, Peltier B, Demondion X, Gueguen G, Migaud H, Fontaine C. A trans STT, trans capitate perilunate dislocation of the carpus. A case report. Ann Chir Main Memb Super 1999; 18: Schliemann B, Langer M, Kösters C. Successful delayed surgical treatment of a scaphocapitate fracture. Arch Orthop Trauma Surg 2011; 131: Shaikh AA, Saeed G Fenton syndrome in an adolescent. J Coll Physicians Surg Pak. 2007; 17 (1): Marcuzzi A, Ozben H, Russomando A, Petit A. Chronic transscaphoid, transcapitate perilunate fracture dislocation of the wrist: Fenton's syndrome. Chir Main Mar 5. doi: /j.main [Epub ahead of print] 20. Rico AA, Holguin PH, Martin JG. Pseudarthrosis of the capitate. J Hand Surg [Br] 1999; 24:

10 Apergis/ Articular injury of the wrist/ Chapter 13 9 FIGURES Fig a, b = A case of classic scaphocapitate syndrome with atypical fracture of the scaphoid. In P-A view, the black arrows indicate the inverted articular surface of the proximal capitate fragment, the fractured dorsal radial rim is indicated with the single black arrow while the white arrow indicates the fracture of the distal scaphoid that could be easily overlooked (a); in L view, the head of the capitate is dorsally displaced and rotated by (asterisk), the white arrow indicates the fractured dorsal radial rim while black arrows indicate the distal and volar location of the scaphoid fracture (b).

11 Apergis/ Articular injury of the wrist/ Chapter Fig a, b= A case of trans-scaphoid, trans-capitate, trans-triquetral dorsal perilunate fracture dislocation. The P-A view shows the displaced fragments of the scaphoid, the displaced fragment of the proximal capitate (asterisk) and the fractured triquetrum (double arrow) (a); the L-view shows the dorsal displacement of the distal capitate, while the head of the capitate (asterisk) is dorsally displaced, rotated by and facing distally (b).

12 Apergis/ Articular injury of the wrist/ Chapter Fig a, b= The proposed classification of capitate injuries which was based on the potentially associated fractured bones (P-A x-ray view) (a); and the possible displacement of the distal capitate, the proximal capitate and the lunate (L x-ray view) (b) (see text).