The Role of Wrist Arthroscopy in Distal Radius Fractures




INTRODUCTION


Why do volar locking plates and early mobilization not give the expected improved outcome when compared with external fixation?


Volar locking plates have given us improved extra-articular accuracy in managing distal radius fractures in the 21st century. However, intra-articular accuracy needs to be improved. Pinning of intra-articular fragments with fluoroscopic assistance has been shown to give acceptable reduction (stepoff less than 1 mm) in only 33% of cases. In contrast, arthroscopy-assisted management has proved to be better than fluoroscopy in this respect.


Consequently, the role of arthroscopy in distal radius fractures today is twofold. First, arthroscopy gives excellent accuracy in the intra-articular reduction as we know that intra-articular incongruity of more than 1 mm is associated with the development of secondary osteoarthrosis. Second, the role of arthroscopy also is to detect and treat associated ligament and cartilage injuries.


Associated ligament and cartilage injuries further explain why volar locking plates and early mobilization do not improve the outcome more than does external fixation (EF). In fact, immobilization with external fixation may better treat some of the associated injuries. Surgeons need to be aware of these problems, identify associated injuries, and manage them to truly improve the overall outcome after distal radius fractures. An associated intercarpal ligament injury can occasionally be seen on plain x-rays with distal radius fractures ( Fig. 12-1 A and B) as well as with scaphoid and other fractures ( Fig. 12-2 ). They may occasionally be suspected on fluoroscopy, but associated soft tissue injuries and occult carpal fractures may be seen up to 50% of the time with magnetic resonance imaging (MRI). However, arthroscopy has become the gold standard in the detection of these injuries in addition to being an adjunct in the management of distal radius fractures.




Figure 12-1


Scapholunate dissociation seen before ( A ) and after (B ) treatment of a displaced distal radius fracture. It is an associated injury often missed or neglected at the time of surgery.



Figure 12-2


Scapholunate dissociation found in association with a distal ulnar fracture . The associated injury was missed or neglected at the time of surgery.




ARTHROSCOPY


Indications


The main indication for arthroscopically assisted management of a distal radius fracture is to achieve intra-articular congruency, especially in cases with an intra-articular stepoff of more than 1 mm that persists after attempted closed reduction ( Fig. 12-3 ). Signs of an associated soft tissue injury, such as widening of the intercarpal joint spaces (see Fig. 12-1 ), a break in Gilula’s lines (i.e., three congruent, concave arches that can drawn along the proximal and distal carpal rows [ Fig. 12-4 ]), and widening or subluxation of the distal radioulnar joint (DRUJ) ( Fig. 12-5 ) are other reasons for considering arthroscopy as an adjunct in the management of distal radius fractures.






Figure 12-3


A 28-year-old man fell from a ladder and sustained a dislocated intra-articular distal radius fracture ( A, posterior view; B, lateral view). After reduction, there was still a 2-mm incongruency of a die-punch fragment, mainly seen centrally on the lateral view ( C, posteroanterior view; D, lateral view). Arthroscopy-assisted reduction was done as well as percutaneous pinning of a grade 3 scapholunate ligament injury ( E, posteroanterior view; F, lateral view). At the 1-year follow-up, there was no sign of persistent incongruency, secondary osteoarthrosis, or scapholunate dissociation ( G, posteroanterior view; H, lateral view).



Figure 12-4


The three carpal lines of Gilula, which, if disrupted, reveal an intercarpal ligament injury.



Figure 12-5


Distal radius fracture manipulated and put in plaster. A, anteroposterior view; B, lateral view. The widening of the distal radioulnar joint was not recognized, and the torn ulnoradial ligament was not treated. Slight dorsal angulation was accepted.


Contraindications


Open fractures, soft tissue injuries, median nerve symptoms, and signs of compartment syndrome are contraindications for wrist arthroscopy.


Surgical Technique


The arthroscopy mobile cart (with TV monitor, video camera, video recorder, and light source) is positioned at the foot of the bed ( Fig. 12-6 ). The fluoroscopy unit or C arm is placed on the same side as the hand table.




Figure 12-6


Arthroscopy with standard technique. Monitor is at foot end, and longitudinal traction is with a traction tower.


Axillary block or general anesthesia is recommended for arthroscopy, which is performed preferably 2 to 5 days after the trauma. The hand is placed in an upright position, either with an overhead traction boom, as for shoulder arthroscopy, or with a traction tower. The shoulder is in 60 to 90 degrees of abduction with the elbow flexed to 90 degrees. After exsanguination of the arm, the finger traps are placed on the index and long fingers with approximately 4 to 5 kg of traction. This traction often facilitates the reduction of the extra-articular fracture component. An elastic dressing is wrapped around the forearm to minimize the risk of extravasation into muscle compartments.


Swelling distorts the normal landmarks for the portals. The surface landmarks for establishing the 3-4 portal can be approximated by combining a line along the radial side of the middle finger that intersects with a horizontal line drawn along the tip of the radial styloid and the distal, dorsal rim of the radius and the ulnar head. A needle is introduced into the 3-4 portal, and the hemarthrosis is aspirated to confirm proper position. Saline (5 to 10 mL) is injected into the joint.


A small scalpel incision is followed by wound spread technique and insertion of a cannula and blunt trochar, then by a 2.7-mm small joint arthroscope. Dry technique is optional to minimize the risk of extravasation with a secondary compartment syndrome. It is often necessary to lavage the joint through an outflow portal in the 6U portal. Blood clots and debris can also be removed with a motorized, small joint shaver through the 4-5 portal or 6R working portal ( Fig. 12-7 ). Continuous irrigation with saline solution by gravity flow from an elevated bag is most often carried out. With this method, the intra-articular pressure is kept as low as possible to minimize the risk of extravasation of fluid and thus decrease the risk of postoperative carpal tunnel syndrome and compartment syndrome. Once again, an option is to use the dry technique after the initial lavage of the joint. After having cleared the view, the examination starts by evaluating associated injuries to cartilage and ligaments.




Figure 12-7


Lavage of the joint in which a motorized shaver is sometimes needed to clear debris and blood clots.


Modified Horizontal Wrist Arthroscopy


The standard upright position often makes internal fixation difficult after the joint surface is reduced. Many fractures have comminution of the metaphysis and need additional treatment such as volar or dorsal plates, external fixator, or cancellous bone grafting. Therefore, it is preferable to do the arthroscopy with a modified horizontal technique ( Fig. 12-8 A).




Figure 12-8


Modified horizontal arthroscopy technique facilitates complete management of distal radius fractures. A, The operating room during horizontal arthroscopy, with the mobile cart at the foot end of the patient. B, Horizontal traction over a handle on a normal hand table. C, The forearm is blocked in pronation with parallel bars. D, Arthroscopy with the modified horizontal technique is done with standard instruments.


Traction is applied on the index and middle fingers with the traction force applied horizontally over a handle on a regular hand table ( Fig. 12-8 B). The wrist is slightly elevated over the hand table and blocked with bars, which holds the forearm in pronation ( Fig. 12-8 C). Arthroscopy with the horizontal technique is sometimes more technically demanding, but it is otherwise done as described in the previous and following text ( Fig. 12-8 D), with realignment of the joint as well as assessment and treatment of associated injuries. Moreover, the horizontal position allows one to proceed with any additional necessary techniques without changing the traction or position of the wrist. This secures the reduction of the extra-articular component and facilitates further procedures of the fracture or associated injuries.


Arthroscopically Assisted Reduction


Most displaced fragments must be mobilized before they can be reduced, even if some fragments may be reduced by longitudinal traction alone. The reduction is done either with a probe within the joint ( Fig. 12-9 ) or with an elevator through a separate skin incision over the fracture. Kirschner (K) wires are placed centrally in each fragment. Depressed fragments are elevated through combined manipulation with the probe and elevator and with a joystick maneuver of the K wire. Under arthroscopic control, the fracture fragments are sequentially reduced.




Figure 12-9


Depressed fragments are elevated arthroscopically. This arthroscopic view of the lunate facet shows a depressed die-punch fragment (the dorsum of the wrist to the left). The fragment is mobilized with a probe within the joint, while an elevator is used from the fracture outside the joint.


The first step is the realignment of the ulnar border of the radius because it represents a double-joint incongruency both in the sigmoid notch of the DRUJ and in the lunate facet of the radiocarpal joint ( Fig. 12-10 A). The next step is to add further fragments to the ulnar platform by positioning K wires from larger to smaller fragments ( Fig. 12-10 B). Afterward, the realignment of the joint surface is determined arthroscopically ( Fig. 12-11 ). Fluoroscopy confirms that the pins are in proper position with appropriate length. It is preferable to leave the pins outside the skin because this minimizes the risk of injuries to tendons and the superficial branch of the radial nerve. Finally, the extra-articular fracture component, the cancellous defect, and associated injuries are evaluated, and additional procedures are considered.




Figure 12-10


Realign the double joint incongruency. A, it is preferable to start the reconstruction of the incongruent joint surface with the ulnar border of the radius (fragments 1 to 2). This creates bony congruency for both the distal radioulnar and the radiocarpal joints, hereby minimizing the risk for instability as well as post-traumatic secondary osteoarthritis. The next step is to realign the other fragment (3) to the ulnar platform. B, The intra-articular fragments are pinned after the reduction.



Figure 12-11


Arthroscopic confirmation of proper congruency after the elevation and fixation of the depressed fragment.




SPECIFIC FRACTURE TYPES


Radial Styloid Fracture (Chauffeur Fracture)


Radial styloid fracture may be part of a trans-styloid perilunate mechanism ( Fig. 12-12 ); therefore, associated injuries to the lesser or greater arch need to be ruled out. In addition, there is often rotation of the displaced fragment, that is underestimated. Arthroscopically, this is seen with inverted incongruencies dorsally and volarly ( Fig. 12-13 ). The fragment is best reduced with the wrist in supination and the elbow flexed to neutralize the brachioradialis force. With a K wire on the tip of the styloid, palmar to the first extensor compartment, the fragment is reduced and the wire is secured into the radius. Next, a second K wire or a cannulated screw is needed for rotational stability.




Figure 12-12


Radial styloid fracture as part of a transstyloid perilunate dislocation with all the signs of the Mayfield chain of intercarpal ligament injuries.



Figure 12-13


Radial styloid fractures often have rotational incongruency. This arthroscopic view shows the common finding of rotational incongruency in radial styloid fractures, which is revealed with the inverted joint incongruencies palmarly and dorsally (palmar aspect in the bottom with the radial styloid to the right).


Lunate Die-Punch Fragment


If the fragment is not impacted, it is often reduced by traction and some palmar flexion. The reduction can be kept in place with one or two transverse subchondral K wires. Care is taken not to penetrate the DRUJ.


If the fragment is impacted, it is disimpacted and mobilized either with a probe within the joint or with an elevator through a 1- to 2-cm separate skin incision over the fracture (see Fig. 12-9 A). When the joint surface is congruent, as determined with arthroscopy (see Fig. 12-11 ), two transverse subchondral K wires can secure the position (see Fig. 12-1 ). In this situation, additional treatment of the metaphyseal void, by means of bone graft or bone substitution, may be considered.


Partial Palmar Fragments


Partial palmar fragments represent a spectrum of complex injuries to the radiocarpal stabilizing ligaments either as isolated ligament tears ( Fig. 12-14 ) or as ligamentous avulsion fractures. The teardrop is the U -shaped outline of the volar rim of the lunate facet. An abnormal teardrop angle (75 degrees) occurs with displacement of this fragment ( Fig. 12-15 ).




Figure 12-14


Extrinsic radiocarpal ligament tear possibly causing radiocarpal subluxation and late instability.



Figure 12-15


Distal radius fracture with a palmar fragment that was recognized after the initial reduction and external fixation. It is called the teardrop sign and represents the insertion of the important radiocarpal ligament causing radiocarpal instability if not detected and addressed with open reduction and internal fixation.


As a general guideline, partial palmar fragments cannot be reduced by traction owing to the strong palmar radiocarpal ligaments, in which traction only increases the incongruency. Consequently, they need an open reduction and osteosynthesis with a fragment-specific screw or volar plate (see Fig. 12-15 ). However, in some cases the fragments might be reduced by decreasing the traction and flexing the radiocarpal joint palmarly. In such cases, they can be pinned from the dorsal aspect of the distal radius or from the palmar aspect through a limited palmar approach.




ADDITIONAL FRACTURE TREATMENT


Cortical Fracture Treatment





  • Dorsal displacement: Many surgeons nowadays fix the extra-articular displacement with a volar locking plate. Other options are open reduction with fragment-specific plates, other mini-plates, and/or screws. External fixation can be considered in extra-articular comminuted fractures to stabilize the fracture alone or for neutralization after additional fixation.



  • Dorsoulnar fragments: One option is mini-invasive reduction and percutaneous pinning according to the technique recommended by Geissler and associates. Another option is open reduction of ulnar-sided fractures, which can be part of managing a combined intra- and extra-articular fracture. The fragments can be fixed according to the surgeon’s preference with single screws for partial dorsoulnar fragments or various types of dorsal or palmar plates.



  • Palmar displacement: In these cases, it is preferable to start with an evaluation of any intra-articular incongruency and assess associated injuries. The modified horizontal technique is especially useful, since the traction is maintained after the arthroscopic examination. By rotating the forearm into supination, it is possible to continue with the palmar plating technique without losing the fracture reduction. An option is to start with the palmar incision with dissection down to the extra-articular part of the fracture, after which the arthroscope can be introduced between the palmar radiocarpal ligaments just distal to the watershed line, which refers to the line at the highest (most volar) margin of the radius, where the volar wrist ligaments are attached ( Fig. 12-16 ).


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Jul 10, 2019 | Posted by in ORTHOPEDIC | Comments Off on The Role of Wrist Arthroscopy in Distal Radius Fractures

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