- Email: [email protected]
Complications of distal radius locking plates
Injury, Int. J. Care Injured 44 (2013) 336–339
Contents lists available at SciVerse ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Complications of distal radius locking plates ¨ zaksar Tulgar Toros, Tahir Sadık Su¨gu¨n *, Kemal O Orthopaedic Surgeon: Hand and Microsurgery, Orthopaedics and Traumatology (EMOT) Hospital, Turkey
A R T I C L E I N F O
A B S T R A C T
Keywords: Distal radius Fracture Locking plate Complication
Fixation of distal radius fractures via locking plates is an increasingly popular method. However, these plates include variety of complications, such as flexor and extensor tenosynovitis, tendon injury and intra articular screw or peg penetration. Although they offer superior stability and early mobility, if used improperly; they may cause serious complications related to the implant. Proper use of the implant with strict adherence to the fixation principles and close follow up of patients are very important in order to decrease the rate and severity of complications. ß 2013 Elsevier Ltd. All rights reserved.
Introduction
Tenosynovitis
Over the past decade, there has been a growing trend toward internal fixation of distal radial fractures due to the development of low profile anatomically preshaped implants with locking fixation. The main advantages of locking plates are immediate stability allowing early mobilisation, superior stiffness and axial loading strength compared to standard plates. Enabling secure fixation of distally located comminuted intra articular fractures even with severely osteopenic bones seems like another advantage. Also, the rigid angle bar plate permits a dorsally displaced distal radius fracture to be treated with a palmar approach.1 In many of the cases, rigid fixation eliminates bone grafting of impacted sites. Anatomical shapes serve as a template function for reduction.2 Various types of dorsal and volar locking plate systems have been developed and used. Although promising results have been reported, these systems are not without complications. As more studies appeared in the literature, many complications related to this technique have been described. The overall complication rates given for distal radius locking plates are high as 22–27% in the literature.1,3 This high number includes symptomatic, as well as asymptomatic tenosynovitis, which seems to be the most frequent complication observed in the literature (57% of the total number of complications in Arora’s series1). When asymptomatic synovitis is excluded; this rate seems to decrease significantly.
Problems related to tendon irritation seem to be the leading complication in almost all series. Both volar and dorsal plating is blamed to cause tenosynovitis. Tenosynovitis includes a wide spectrum of diagnosis; from asymptomatic mild effusion around the tendons to massive synovitis leading to tendon rupture. As the surgeons became more aware of this complication and use specific imaging tools like ultrasound (USG) for detection, the reported rate of this complication has increased greatly. In a report of prospective study, the authors state that 23% of their operated patients developed extensor tendinitis within the follow-up period.4 Similarly, in our series, using ultrasonography as the imaging tool, we found out that almost 1/4 of distal locking screws caused extensor tendon synovitis.5 Despite this high rate of extensor tendon irritation, most of these cases were totally asymptomatic, and the diagnosis was made during routine follow up visits. The surgeons’ attitude towards these patients should be no different from patients with symptomatic tenosynovitis. In the light of recent literature, we consider asymptomatic tenosynovitis of long duration as a risk factor for progressive tendon damage and observe it as a complication.1 The pathologic process of irritation of the synovium and tendons by screws or plates may be symptom free at the beginning of the process, which may become symptomatic at a certain time and if not addressed properly, it may end up with tendon laceration. In order to prevent the progression of the ongoing pathology and impending tendon ruptures, early implant removal is advised in all patients who develop tenosynovitis.1
* Corresponding author at: Hand and Microsurgery, Orthopaedics and Traumatology (EMOT) Hospital, 1418 Sokak No. 14, 35230 Kahramanlar, I˙zmir, Turkey. Tel.: +90 232 441 01 21; fax: +90 232 441 16 44. E-mail address: [email protected] (T.S. Su¨gu¨n). 0020–1383/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2013.01.008
Dorsal plate complications Compared to volar fixation, dorsal plating seems advantageous because of the buttress effect of the plate. It strengthens the
T. Toros et al. / Injury, Int. J. Care Injured 44 (2013) 336–339
weakened and crushed area of the cortex, as there is usually a bony contact at the volar side. Also, the dorsal approach provides easy access to the intra articular pathology. The dorsal plate bears much lower axial and bending loads, since it has been applied on the side of cortical comminution. Despite all these advantages, experience with dorsal plating has been discouraging.6–8 The most important complications related to dorsal plating are persistent extensor tenosynovitis, tendon ruptures and adhesions, due to the tight anatomical constraints at this area. The 2nd, 3rd and 4th extensor compartments course directly on the surface of the bone for a considerable distance making it problematic to insert a metal plate and screws between bone and tendons.8 Most surgeons usually avoid dorsal plating because of the aforementioned disadvantages and frequent tendon irritation which needs a secondary operation for plate removal. Although this complication has been decreased by the design of lower profile plates, studies still report high numbers of tendon irritation due to dorsal fixation. In one study, results of ‘pi plateß’ fixation showed that 5 of the 22 reported patients had extensor tenosynovitis. The authors do not report any extensor tendon ruptures and routine removal of the plate is not advocated.4 In contrast Fernandez and Fitoussi recommend a routine removal of the plate and screws in all patients.9,10 Axelrod et al. reported that 5 of the 15 patients whom a dorsal plate was applied developed extensor tenosynovitis, which required a second procedure to remove the implants.11 A practical way of preventing extensor tenosynovitis is elevating the fourth dorsal compartment subperiosteally off the distal radius, preserving a thick cuff of soft tissue around the tendons, and inserting the plate on the raw bony surface and cover the exposed surface of the plate with the elevated tissue to provide good coverage between the bone and the extensor tendons.12 Another recommendation of plate placement includes fashioning of a retinacular flap under the fourth dorsal compartment and covering the dorsal surface of the plate with this flap in order to protect the tendons of the second dorsal compartment from the devastating effect of the plate.4 However, extensive release of the extensor mechanism from the radius and attempts to cover the plate with the extensor retinaculum may end up with bowstringing of the tendons. There are no reports of any injury to the flexor tendons after use of the dorsal plate. Volar plate complications Volar side of the distal radius seems more suitable for application of fixation implants since there is more place between the bone and flexor tendons.8,12,13 Also pronator quadratus muscle on this side can be used to cover the volar side of the implant, forming a cushion between the plate and flexor tendons. Volar plating has gained more popularity than dorsal approaches because the zone of dorsal comminution is not violated, leaving its blood supply undisturbed and there are fewer reported soft tissue complications such as tendon irritation and rupture.8,11,12,14–16 Although it is applied away from the comminution site of the fracture, volar fixed angle plates provide stable fracture fragment fixation and have shown to restore radial length, volar tilt and articular congruity in long term follow-up.17,18 Despite all efforts to avoid soft tissue irritation, tenosynovitis is still the leading complication; extensively reported in palmar side as well as in dorsal side. The most commonly reported mechanism of extensor tendon irritation is caused due to the prominent distal edges of the screws penetrating dorsal extensor compartments3 (Fig. 1). The close proximity of bone and tendons and tight extensor compartments on the dorsal side is a potential area for tendon irritation. This confined area does not tolerate any foreign materials; and inadvertent penetration of the tips of the locking screws within
337
Fig. 1. X-ray and ultrasonographic appearance of locking screw penetration of the dorsal radial cortex and extensor tendon synovitis.
the tight compartments causes a direct contact of the screw pitches with the extensor tendons.8 The 2nd, 3rd and 4th extensor compartments seem to be the most violated compartments.17 The EPL tendon is reported to be the most ruptured tendon, due to the limited space of the 3rd compartment, relatively long excursion and the torturous course of the tendon with a sharp curve around the Lister’s tubercle.1,17 Because of all the listed disadvantages of this compartment, even the slight penetration of the dorsal cortex causes severe impingement of the tendon causing severe abrasion leading to rupture. The complex anatomy and irregular shape of the dorsal cortex of the distal radius makes it quite difficult to confirm appropriate screw length with fluoroscopic controls or standard radiographic imaging techniques.1,19 Special views have been described in the literature in order to increase the detection of screw penetrance, including pronation and supination views and skyline views.20 USG imaging seems to be a reliable modality easier to perform compared to MRI and CT (Fig. 1). The high complication rates presented in the literature forced surgeons to downsize distal screws inserted on distal holes of the plate.1 Such a practice may prevent dorsal screw penetration, but may cause insufficient engagement of the dorsal cortex fragments in dorsally comminuted intra articular fragments, leading to intra articular step formation and dorsal tilting of the distal articular surface. In extreme cases, short distal screws may have the potential to loosen and loss of fracture reduction. Secure fixation of the dorsal cortex by long screws may be unavoidable in such complex fractures. However, if dorsal rim fractures necessitate dorsal cortical screw purchase, these patients should be closely followed and screws should be taken out at the first sign of tendon irritation. Flexor tenosynovitis due to volar plating has also been reported.1,3 Very distal placement of the plate beyond the watershed line is blamed as the major cause of this complication. Drobetzand Kutscha-Lissberg reported 6 cases of FPL tendon rupture in 50 fractures, which was attributed to placing the plate too far distal.21 Prominent screw heads caused by inappropriate purchase of the pitches of the screws and plate holes is another
T. Toros et al. / Injury, Int. J. Care Injured 44 (2013) 336–339
338
reason reported in the literature.1,3 The pronator quadratus muscle should be carefully dissected from the distal and ulnar edges without violating the muscle mass. At the end of the operation, this muscle should be secured to bone as distally as possible to cover the distal end of the plate and distal screws in order to prevent direct contact of hardware with the moving tendons. Placement of dorsal plates to palmar side is another reported practice leading to flexor tendon laceration. Such plates do not fit the contours of the bone, leaving protruding edges, which impinge on flexor tendons.15 Rupture of flexor pollicis longus (FPL) may occur due to chronic abrasion of tendon by protruding screws from palmar plate, or inappropriate placement of the plate.1,15,21 FPL is the deepest located tendon on the volar radial side of the wrist and any implant located at this site lies in close proximity with tendon. Implant locations distal to pronator quadratus muscle expose the distal edge of the plate that may impinge and abrade the tendon.1,22,23 The intact volar carpal ligament may also aggravate the problem, exerting pressure of the contents of the carpal tunnel towards the implant. Proper placement of the implant and creating a smooth volar surface without any protruding screws from the plate is mandatory to overcome this problem. Routine release of the volar carpal ligament is not recommended. Drobetz et al. reported rupture of the FPL tendon as the most common complication in their series at an average of 10 months postoperatively and started to remove the plate routinely four months after surgery.21 Implant loosening Loosening of the plate and screw/peg back out can be seen rarely. Severely osteoporotic bone usually is the main reason of
Fig. 2. Appearance of articular screw penetration on the dorsal side after volar locking plate fixation between scaphoid and radius intraoperatively (arrow).
failure. Comminuted fractures, short screws with poor purchase of bone, and screws, which do not engage the dorsal cortex are especially at risk for loosening. Such patients should be told not to force their wrists in early postoperative period. Although locking plate systems provide sufficient early stability of the fracture site, forceful activities early in the postoperative period before bony union is still risky and should not be allowed. Grafting of the comminution site to strengthen the fixation construct may be a logical solution if adequate fixation cannot be achieved
Fig. 3. Insufficient ulnar fragment fixation due to inappropriate plate placement and loss of reduction at the 3rd postoperative month.
T. Toros et al. / Injury, Int. J. Care Injured 44 (2013) 336–339
intraoperatively.11 Although these implants provide superior fixation than conventional plates and screws, adequate postoperative protection is still recommended for most cases.3 Articular screws/pegs Unintentional intra articular screw/peg placement is seen in patients operated with poor peroperative fluoroscopic control. Very distal fractures with intra articular comminution pose the greatest risk for this complication. The most distal screws/pegs of the system should ideally be inserted underneath the subchondral bone in order to neutralise the forces applied to the articular side for preventing collapse of the articular fractures and eliminating articular step off. Distally placed screws/pegs can easily cut through the subchondral bone and penetrate into joint1 (Fig. 2). The most ulnar screw/peg has the highest risk for intra articular penetration. The usual guide is to locate the distal end of the plate proximal or in line with the watershed line of the distal radius but never distal to this line. Failure to achieve proper placement may result with loss of congruity between the volar bony inclination of radius and the plate; resulting dorsal tilt of the distal articular surface and unintentional penetration of distal articular surface by the screws. The majority of radial styloid and distal radio ulnar penetrations occur when the plate is too wide for radius.2 On the other hand, if the plate is smaller than the width of distal radius, insufficient fixation of fragments may be seen (Fig. 3). Proper plate width should be confirmed intraoperatively with use of fluoroscopy. Fixed angle locking plates do not allow the surgeon to manipulate the angle of screws/pegs inserted on bone, so proper placement of the plate on distal radius is very important and should be carefully controlled by fluoroscopy before inserting the distal screws. In order to overcome this limitation, variable angle locking systems have been developed, enabling the surgeons to manipulate the angle of the screws inserted on the subchondral bone. Carpal tunnel syndrome Carpal tunnel syndrome is rare and observed as a late complication. The rate of postoperative syndrome reported in the literature ranges from 0.5% to 22%.17,24 Arora et al. reported three patients after a mean postoperative period of 7 months.1,21 They treated all patients with carpal tunnel release and plate removal. Distal placement of the plate and inadequate reduction of the palmar metaphyseal fragment is blamed to increase the carpal tunnel pressure. Prophylactic decompression of carpal tunnel during volar plate application might be a possible solution to prevent postoperative median nerve dysfunction and has been recommended by some authors.16,25 On the other hand, Bienek et al. reported that there is no proven benefit of prophylactic decompression.24 CRPS, persistent pain, delayed union, nonunion, and infection are other complications which can complicate the treatment of distal radius fractures. Conclusion Although locked plates offer superior stability of the fracture fragments providing early safe movement, these systems are not without problems. Exact placement of pre contoured plates with
339
appropriate width and correct length of screws/pegs are essential steps for avoidance of complications. Fracture treatment principles should always be applied properly without any exceptions, and close follow up of the patients should be performed in order to prevent any complications at early phases of its course. Conflicts of Interest There is no conflict of interest.
References 1. Arora R, Lutz M, Hennerbichler A, Krappinger D, Espen D, Gabl M. Complications following internal fixation of unstable distal radius fracture with a palmar locking-plate. J Orthop Trauma 2007;21(5):316–22. 2. Buzzell JE, Weikert DR, Watson JT, Lee DH. Precontoured fixed-angle volar distal radius plates: a comparison of anatomic fit. J Hand Surg Am 2008;33(7): 1144–52. 3. Rozental TD, Blazar PE. Functional outcome and complications after volar plating for dorsally displaced, unstable fractures of the distal radius. J Hand Surg Am 2006;31(3):359–65. 4. Ring D, Jupiter JB, Brennwald J, Bu¨chler U, Hastings H. Prospective multicenter trial of a plate for dorsal fixation of distal radius fractures. J Hand Surg Am 1997;22(5):777–84. 5. Su¨gu¨n TS, Karabay N, Gu¨rbu¨z Y, Ozaksar K, Toros T, Kayalar M. Screw prominences related to palmar locking plating of distal radius. J Hand Surg Eur Vol 2011;36(4):320–4. 6. Louis DS. Prospective multi-center trial of a plate for dorsal fixation of distal radius fractures. J Hand Surg Am 1998;23(2):353–4. 7. Nalbantog˘lu U, Gereli A, Uc¸ar Y, Tu¨rkmen M. Comparison between fixation with dorsal T plate and palmar locking plate in the treatment of unstable displaced distal radius fractures. Acta Orthop Traumatol Turc 2008;42(5):365–72. 8. Orbay JL. The treatment of unstable distal radius fractures with volar fixation. Hand Surg 2000;5(2):103–12. 9. Fernandez DL. Reconstructive procedures for malunion and traumatic arthritis. Orthopedic Clin North Am 1993;24(2):341–63. 10. Fitoussi F, Ip WY, Chow SP. Treatment of displaced intra-articular fractures of the distal end of the radius with plates. J Bone Joint Surg 1997;79(9):1303–12. 11. Axelrod TS, McMurtry RY. Open reduction and internal fixation of comminuted, intraarticular fractures of the distal radius. J Hand Surg Am 1990;15(1):1–11. 12. Kambouroglou GK, Axelrod TS. Complications of the AO/ASIF titanium distal radius plate system (pi plate) in internal fixation of the distal radius: a brief report. J Hand Surg Am 1998;23(4):737–41. 13. Ruch DS, Papadonikolakis A. Volar versus dorsal plating in the management of intra-articular distal radius fractures. J Hand Surg Am 2006;31(1):9–16. 14. Chung KC, Watt AJ, Kotsis SV, Margaliot Z, Haase SC, Kim HM. Treatment of unstable distal radial fractures with the volar locking plating system. J Bone Joint Surg 2006;88(12):2687–94. 15. Nunley JA, Rowan PR. Delayed rupture of the flexor pollicis longus tendon after inappropriate placement of the pi plate on the volar surface of the distal radius. J Hand Surg Am 1999;24(6):1279–80. 16. Orbay J. Volar plate fixation of distal radius fractures. Hand Clin 2005;21(3): 347–54. 17. Su¨gu¨n TS, Gu¨rbu¨z Y, Ozaksar K, Toros T, Kayalar M, Bal E. Results of volar locking plating for unstable distal radius fractures. Acta Orthop Traumatol Turc 2012;46(1): 22–5. 18. Wright TW, Horodyski M, Smith DW. Functional outcome of unstable distal radius fractures: ORIF with a volar fixed-angle tine plate versus external fixation. J Hand Surg Am 2005;30(2):289–99. 19. Thomas AD, Greenberg JA. Use of fluoroscopy in determining screw overshoot in the dorsal distal radius: a cadaveric study. J Hand Surg Am 2009;34(2): 258–61. 20. Riddick AP, Hickey B, White SP. Accuracy of the skyline view for detecting dorsal cortical penetration during volar distal radius fixation. J Hand Surg Eur Vol 2012;37(5):407–11. 21. Drobetz H, Kutscha-Lissberg E. Osteosynthesis of distal radial fractures with a volar locking screw plate system. Int Orthop 2003;27(1):1–6. 22. Duncan SF, Weiland AJ. Delayed rupture of the flexor pollicis longus tendon after routine volar placement of a T-plate on the distal radius. Am J Orthop 2007;36(12):669–70. 23. Koo SC, Ho ST. Delayed rupture of flexor pollicis longus tendon after volar plating of the distal radius. Hand Surg 2006;11(1–2):67–70. 24. Bienek T, Kusz D, Cielinski L. Peripheral nerve compression neuropathy after fractures of the distal radius. J Hand Surg Br 2006;31(3):256–60. 25. Hove LM, Nilsen PT, Furnes O, Oulie HE, Solheim E, Mo¨lster AO. Open reduction and internal fixation of displaced intraarticular fractures of the distal radius. 31 patients followed for 3–7 years. Acta Orthop Scand 1997;68(1):59–63.
Contents lists available at SciVerse ScienceDirect
Injury journal homepage: www.elsevier.com/locate/injury
Complications of distal radius locking plates ¨ zaksar Tulgar Toros, Tahir Sadık Su¨gu¨n *, Kemal O Orthopaedic Surgeon: Hand and Microsurgery, Orthopaedics and Traumatology (EMOT) Hospital, Turkey
A R T I C L E I N F O
A B S T R A C T
Keywords: Distal radius Fracture Locking plate Complication
Fixation of distal radius fractures via locking plates is an increasingly popular method. However, these plates include variety of complications, such as flexor and extensor tenosynovitis, tendon injury and intra articular screw or peg penetration. Although they offer superior stability and early mobility, if used improperly; they may cause serious complications related to the implant. Proper use of the implant with strict adherence to the fixation principles and close follow up of patients are very important in order to decrease the rate and severity of complications. ß 2013 Elsevier Ltd. All rights reserved.
Introduction
Tenosynovitis
Over the past decade, there has been a growing trend toward internal fixation of distal radial fractures due to the development of low profile anatomically preshaped implants with locking fixation. The main advantages of locking plates are immediate stability allowing early mobilisation, superior stiffness and axial loading strength compared to standard plates. Enabling secure fixation of distally located comminuted intra articular fractures even with severely osteopenic bones seems like another advantage. Also, the rigid angle bar plate permits a dorsally displaced distal radius fracture to be treated with a palmar approach.1 In many of the cases, rigid fixation eliminates bone grafting of impacted sites. Anatomical shapes serve as a template function for reduction.2 Various types of dorsal and volar locking plate systems have been developed and used. Although promising results have been reported, these systems are not without complications. As more studies appeared in the literature, many complications related to this technique have been described. The overall complication rates given for distal radius locking plates are high as 22–27% in the literature.1,3 This high number includes symptomatic, as well as asymptomatic tenosynovitis, which seems to be the most frequent complication observed in the literature (57% of the total number of complications in Arora’s series1). When asymptomatic synovitis is excluded; this rate seems to decrease significantly.
Problems related to tendon irritation seem to be the leading complication in almost all series. Both volar and dorsal plating is blamed to cause tenosynovitis. Tenosynovitis includes a wide spectrum of diagnosis; from asymptomatic mild effusion around the tendons to massive synovitis leading to tendon rupture. As the surgeons became more aware of this complication and use specific imaging tools like ultrasound (USG) for detection, the reported rate of this complication has increased greatly. In a report of prospective study, the authors state that 23% of their operated patients developed extensor tendinitis within the follow-up period.4 Similarly, in our series, using ultrasonography as the imaging tool, we found out that almost 1/4 of distal locking screws caused extensor tendon synovitis.5 Despite this high rate of extensor tendon irritation, most of these cases were totally asymptomatic, and the diagnosis was made during routine follow up visits. The surgeons’ attitude towards these patients should be no different from patients with symptomatic tenosynovitis. In the light of recent literature, we consider asymptomatic tenosynovitis of long duration as a risk factor for progressive tendon damage and observe it as a complication.1 The pathologic process of irritation of the synovium and tendons by screws or plates may be symptom free at the beginning of the process, which may become symptomatic at a certain time and if not addressed properly, it may end up with tendon laceration. In order to prevent the progression of the ongoing pathology and impending tendon ruptures, early implant removal is advised in all patients who develop tenosynovitis.1
* Corresponding author at: Hand and Microsurgery, Orthopaedics and Traumatology (EMOT) Hospital, 1418 Sokak No. 14, 35230 Kahramanlar, I˙zmir, Turkey. Tel.: +90 232 441 01 21; fax: +90 232 441 16 44. E-mail address: [email protected] (T.S. Su¨gu¨n). 0020–1383/$ – see front matter ß 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.injury.2013.01.008
Dorsal plate complications Compared to volar fixation, dorsal plating seems advantageous because of the buttress effect of the plate. It strengthens the
T. Toros et al. / Injury, Int. J. Care Injured 44 (2013) 336–339
weakened and crushed area of the cortex, as there is usually a bony contact at the volar side. Also, the dorsal approach provides easy access to the intra articular pathology. The dorsal plate bears much lower axial and bending loads, since it has been applied on the side of cortical comminution. Despite all these advantages, experience with dorsal plating has been discouraging.6–8 The most important complications related to dorsal plating are persistent extensor tenosynovitis, tendon ruptures and adhesions, due to the tight anatomical constraints at this area. The 2nd, 3rd and 4th extensor compartments course directly on the surface of the bone for a considerable distance making it problematic to insert a metal plate and screws between bone and tendons.8 Most surgeons usually avoid dorsal plating because of the aforementioned disadvantages and frequent tendon irritation which needs a secondary operation for plate removal. Although this complication has been decreased by the design of lower profile plates, studies still report high numbers of tendon irritation due to dorsal fixation. In one study, results of ‘pi plateß’ fixation showed that 5 of the 22 reported patients had extensor tenosynovitis. The authors do not report any extensor tendon ruptures and routine removal of the plate is not advocated.4 In contrast Fernandez and Fitoussi recommend a routine removal of the plate and screws in all patients.9,10 Axelrod et al. reported that 5 of the 15 patients whom a dorsal plate was applied developed extensor tenosynovitis, which required a second procedure to remove the implants.11 A practical way of preventing extensor tenosynovitis is elevating the fourth dorsal compartment subperiosteally off the distal radius, preserving a thick cuff of soft tissue around the tendons, and inserting the plate on the raw bony surface and cover the exposed surface of the plate with the elevated tissue to provide good coverage between the bone and the extensor tendons.12 Another recommendation of plate placement includes fashioning of a retinacular flap under the fourth dorsal compartment and covering the dorsal surface of the plate with this flap in order to protect the tendons of the second dorsal compartment from the devastating effect of the plate.4 However, extensive release of the extensor mechanism from the radius and attempts to cover the plate with the extensor retinaculum may end up with bowstringing of the tendons. There are no reports of any injury to the flexor tendons after use of the dorsal plate. Volar plate complications Volar side of the distal radius seems more suitable for application of fixation implants since there is more place between the bone and flexor tendons.8,12,13 Also pronator quadratus muscle on this side can be used to cover the volar side of the implant, forming a cushion between the plate and flexor tendons. Volar plating has gained more popularity than dorsal approaches because the zone of dorsal comminution is not violated, leaving its blood supply undisturbed and there are fewer reported soft tissue complications such as tendon irritation and rupture.8,11,12,14–16 Although it is applied away from the comminution site of the fracture, volar fixed angle plates provide stable fracture fragment fixation and have shown to restore radial length, volar tilt and articular congruity in long term follow-up.17,18 Despite all efforts to avoid soft tissue irritation, tenosynovitis is still the leading complication; extensively reported in palmar side as well as in dorsal side. The most commonly reported mechanism of extensor tendon irritation is caused due to the prominent distal edges of the screws penetrating dorsal extensor compartments3 (Fig. 1). The close proximity of bone and tendons and tight extensor compartments on the dorsal side is a potential area for tendon irritation. This confined area does not tolerate any foreign materials; and inadvertent penetration of the tips of the locking screws within
337
Fig. 1. X-ray and ultrasonographic appearance of locking screw penetration of the dorsal radial cortex and extensor tendon synovitis.
the tight compartments causes a direct contact of the screw pitches with the extensor tendons.8 The 2nd, 3rd and 4th extensor compartments seem to be the most violated compartments.17 The EPL tendon is reported to be the most ruptured tendon, due to the limited space of the 3rd compartment, relatively long excursion and the torturous course of the tendon with a sharp curve around the Lister’s tubercle.1,17 Because of all the listed disadvantages of this compartment, even the slight penetration of the dorsal cortex causes severe impingement of the tendon causing severe abrasion leading to rupture. The complex anatomy and irregular shape of the dorsal cortex of the distal radius makes it quite difficult to confirm appropriate screw length with fluoroscopic controls or standard radiographic imaging techniques.1,19 Special views have been described in the literature in order to increase the detection of screw penetrance, including pronation and supination views and skyline views.20 USG imaging seems to be a reliable modality easier to perform compared to MRI and CT (Fig. 1). The high complication rates presented in the literature forced surgeons to downsize distal screws inserted on distal holes of the plate.1 Such a practice may prevent dorsal screw penetration, but may cause insufficient engagement of the dorsal cortex fragments in dorsally comminuted intra articular fragments, leading to intra articular step formation and dorsal tilting of the distal articular surface. In extreme cases, short distal screws may have the potential to loosen and loss of fracture reduction. Secure fixation of the dorsal cortex by long screws may be unavoidable in such complex fractures. However, if dorsal rim fractures necessitate dorsal cortical screw purchase, these patients should be closely followed and screws should be taken out at the first sign of tendon irritation. Flexor tenosynovitis due to volar plating has also been reported.1,3 Very distal placement of the plate beyond the watershed line is blamed as the major cause of this complication. Drobetzand Kutscha-Lissberg reported 6 cases of FPL tendon rupture in 50 fractures, which was attributed to placing the plate too far distal.21 Prominent screw heads caused by inappropriate purchase of the pitches of the screws and plate holes is another
T. Toros et al. / Injury, Int. J. Care Injured 44 (2013) 336–339
338
reason reported in the literature.1,3 The pronator quadratus muscle should be carefully dissected from the distal and ulnar edges without violating the muscle mass. At the end of the operation, this muscle should be secured to bone as distally as possible to cover the distal end of the plate and distal screws in order to prevent direct contact of hardware with the moving tendons. Placement of dorsal plates to palmar side is another reported practice leading to flexor tendon laceration. Such plates do not fit the contours of the bone, leaving protruding edges, which impinge on flexor tendons.15 Rupture of flexor pollicis longus (FPL) may occur due to chronic abrasion of tendon by protruding screws from palmar plate, or inappropriate placement of the plate.1,15,21 FPL is the deepest located tendon on the volar radial side of the wrist and any implant located at this site lies in close proximity with tendon. Implant locations distal to pronator quadratus muscle expose the distal edge of the plate that may impinge and abrade the tendon.1,22,23 The intact volar carpal ligament may also aggravate the problem, exerting pressure of the contents of the carpal tunnel towards the implant. Proper placement of the implant and creating a smooth volar surface without any protruding screws from the plate is mandatory to overcome this problem. Routine release of the volar carpal ligament is not recommended. Drobetz et al. reported rupture of the FPL tendon as the most common complication in their series at an average of 10 months postoperatively and started to remove the plate routinely four months after surgery.21 Implant loosening Loosening of the plate and screw/peg back out can be seen rarely. Severely osteoporotic bone usually is the main reason of
Fig. 2. Appearance of articular screw penetration on the dorsal side after volar locking plate fixation between scaphoid and radius intraoperatively (arrow).
failure. Comminuted fractures, short screws with poor purchase of bone, and screws, which do not engage the dorsal cortex are especially at risk for loosening. Such patients should be told not to force their wrists in early postoperative period. Although locking plate systems provide sufficient early stability of the fracture site, forceful activities early in the postoperative period before bony union is still risky and should not be allowed. Grafting of the comminution site to strengthen the fixation construct may be a logical solution if adequate fixation cannot be achieved
Fig. 3. Insufficient ulnar fragment fixation due to inappropriate plate placement and loss of reduction at the 3rd postoperative month.
T. Toros et al. / Injury, Int. J. Care Injured 44 (2013) 336–339
intraoperatively.11 Although these implants provide superior fixation than conventional plates and screws, adequate postoperative protection is still recommended for most cases.3 Articular screws/pegs Unintentional intra articular screw/peg placement is seen in patients operated with poor peroperative fluoroscopic control. Very distal fractures with intra articular comminution pose the greatest risk for this complication. The most distal screws/pegs of the system should ideally be inserted underneath the subchondral bone in order to neutralise the forces applied to the articular side for preventing collapse of the articular fractures and eliminating articular step off. Distally placed screws/pegs can easily cut through the subchondral bone and penetrate into joint1 (Fig. 2). The most ulnar screw/peg has the highest risk for intra articular penetration. The usual guide is to locate the distal end of the plate proximal or in line with the watershed line of the distal radius but never distal to this line. Failure to achieve proper placement may result with loss of congruity between the volar bony inclination of radius and the plate; resulting dorsal tilt of the distal articular surface and unintentional penetration of distal articular surface by the screws. The majority of radial styloid and distal radio ulnar penetrations occur when the plate is too wide for radius.2 On the other hand, if the plate is smaller than the width of distal radius, insufficient fixation of fragments may be seen (Fig. 3). Proper plate width should be confirmed intraoperatively with use of fluoroscopy. Fixed angle locking plates do not allow the surgeon to manipulate the angle of screws/pegs inserted on bone, so proper placement of the plate on distal radius is very important and should be carefully controlled by fluoroscopy before inserting the distal screws. In order to overcome this limitation, variable angle locking systems have been developed, enabling the surgeons to manipulate the angle of the screws inserted on the subchondral bone. Carpal tunnel syndrome Carpal tunnel syndrome is rare and observed as a late complication. The rate of postoperative syndrome reported in the literature ranges from 0.5% to 22%.17,24 Arora et al. reported three patients after a mean postoperative period of 7 months.1,21 They treated all patients with carpal tunnel release and plate removal. Distal placement of the plate and inadequate reduction of the palmar metaphyseal fragment is blamed to increase the carpal tunnel pressure. Prophylactic decompression of carpal tunnel during volar plate application might be a possible solution to prevent postoperative median nerve dysfunction and has been recommended by some authors.16,25 On the other hand, Bienek et al. reported that there is no proven benefit of prophylactic decompression.24 CRPS, persistent pain, delayed union, nonunion, and infection are other complications which can complicate the treatment of distal radius fractures. Conclusion Although locked plates offer superior stability of the fracture fragments providing early safe movement, these systems are not without problems. Exact placement of pre contoured plates with
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appropriate width and correct length of screws/pegs are essential steps for avoidance of complications. Fracture treatment principles should always be applied properly without any exceptions, and close follow up of the patients should be performed in order to prevent any complications at early phases of its course. Conflicts of Interest There is no conflict of interest.
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