Fig. 18.1
General principles in managing distal radius fracture with arthroscopy assistance in a stepwise fashion. From easier two-fragment fractures managed by the relatively inexperienced surgeon, through three or four-part fractures dealt with by an experienced surgeon. The multi-fragmentary or so-called explosion fractures is for the expert. The fat arrows demonstrate how a comminuted radial styloid fracture moves through the flow chart into a final fragment specific radial styloid plate fixation
The Arthroscopic Procedure: Radial Styloid Fracture (Chauffeur’s Fracture); a Two-Fragment Fracture
Radial styloid fractures are the first and possibly most important intra-articular fracture to approach with arthroscopy assistance. It is normally a two-fragment fracture so it does not need a volar locking plate and can normally be reduced and fixed with ease. The styloid fragment is often rotated in pronation in relation to the radius.
More importantly, it may also be part of a greater arch trans-styloid perilunate injury as described by Mayfield, but without the lunate dislocation [18]. It may therefore have associated injuries to the lesser or greater arch that can either be detected or ruled out with arthroscopy.
Once the overview assessment has been done and the intra-articular fragments have to be mobilised and reduced, the viewing portal has to be switched to a 4-5 or 6R portal away from the fracture as the scope otherwise will block free mobilisation of the fragment.
The reduction is done either with a probe within the joint or with an elevator through a separate skin incision over the fracture. The displaced fragment is frequently rotated, which is often underestimated. Arthroscopically this is seen with ‘inverted’ incongruencies dorsally and volarly. It will ease the reduction of the fragment when the forearm is in neutral rotation or supinated with the elbow flexed to neutralise the force of the brachioradialis tendon inserted in this fragment.
Under fluoroscopic guidance, a K-wire is inserted palmar to the first extensor compartment through the tip of the styloid. The fragment is reduced using the K-wire as a joystick and arthroscopic assessment of the reduction before the wire is secured into the radius. A second K-wire is inserted across the fracture to provide rotational stability. Once anatomic reduction is confirmed, either a cannulated or compression screw can be inserted.
The Arthroscopic Procedure: Radial Styloid Fracture; a Two-Fragment Comminuted Fracture
Radial styloid fractures with comminution can be reduced as described above, but single screws will not maintain stability. More commonly, a fragment specific radial styloid plate is used to maintain reduction by buttressing the fracture.
The Arthroscopic Procedure: Impacted, Three to Four Fragment and Explosion Fractures
These fractures are all for the more experienced arthroscopist. The arthroscopic procedure follows a provisional fixation of the extra-articular fracture with a volar locking plate.
The Arthroscopic Procedure: General Surgical Technique for the Volar Locking Plate
The general approach for most surgeons is to reduce and provisionally fix the extra-articular fracture before proceeding with the arthroscopic assessment. The distal radius fracture is most often approached through the flexor carpi radialis (FCR) bed and the volar locking plate is applied and provisionally stabilised by inserting a screw in the elliptical hole in the plate to allow later adjustments. The plate should be positioned to allow the distal row of pegs/screws to lie in the subchondral bone. The metaphyseal fragments are manipulated with traction, compression and manual reduction under direct visualisation as well as fluoroscopic guidance, possibly with the wrist in some flexion. K-wires are applied stabilising the articular fragments to the plate using the auxiliary holes. Once the provisional stabilisation seems adequate, another cortical screw is inserted in the plate to secure its position in order to avoid any secondary displacement.
Special emphasis is directed towards the intermediate column, also called the critical corner to support the important lunate facet.
Once the extra-articular fracture has been provisionally fixed, including provisional fixation of the intra-articular fractures with K-wires in the auxiliary distal holes, the traction system is used for the arthroscopic procedure of either securing the fragments or fine-tuning reduction.
The Arthroscopic Procedure: Post-plating Assessment and Reduction of Impacted and Other Fragments
After provisional reduction of the intra-articular fracture component with the open approach, the accuracy of the intra-articular fracture is assessed arthroscopically.
Occasionally, in simpler cases, the reduction is acceptable and the following part is to sequentially fix the fracture to the distal plate with pegs/screws for a final arthroscopic and fluoroscopic confirmation of a well-reduced fracture.
As a general principle for the arthroscopic reduction, a K-wire is placed centrally in each fragment. Thereafter, depressed fragments are mobilised and elevated through combined manipulation with the probe and/or elevator using a joystick manoeuvre of the K-wire. Thus the fracture fragments are sequentially reduced under arthroscopic control.
1.
The first step in the reduction is the realignment of the ulnar border of the radius as it represents a ‘double-joint incongruency’ both in the sigmoid notch of the DRU joint and in the lunate facet of the radiocarpal joint [24]. Furthermore, it secures the important critical corner of the intermediate column.
2.
The arthroscope has to be moved away from the 3-4 to 6R portal to allow free mobilisation of the lunate facet. Elevate a depressed lunate fragment with a probe, which may be further supported proximally with a percutaneous K-wire. If the lunate facet is split into volar and dorsal fragments, then a K-wire in the lunate fragment is used as a joystick to move the related articular fragments. With digital pressure of the surgeon’s thumb from the dorsum, the fragments are brought closer to the plate and are provisionally stabilised with a K-wire.
3.
Further fragments are added to the ‘ulnar platform’ by sequentially positioning K-wires from larger to smaller fragments.
4.
After all fragments have been provisionally reduced and fixed with K-wires, the realignment of the joint surface is determined arthroscopically and fluoroscopically. Once the joint surface is congruent, two transverse subchondral K-wires can further secure the reduced position.
5.
Once this is established the palmar plate is fixed with all distal pegs or screws inserted.
6.
Hereafter, arthroscopy and fluoroscopy again confirm a solid fixation and all K-wires are either removed or in selected cases converted into screw fixations, either cannulated or mini-fragment screws.
7.
Finally, associated injuries including ligaments and cartilage are assessed and treated if necessary.
The Arthroscopic Procedure: ‘Explosion-Type’ Fractures
An extreme form of multi-fragmentary fractures has been described as ‘explosion-type’ fractures [20]. They pose a unique challenge for arthroscopy-assisted fixation even for the expert. Explosion-type fractures are defined as having more than four articular fragments and with a single, free, central osteochondral fragment [20]. The osteochondral fragments, due to the paucity of their attachments, bear a high risk of settling into the metaphyseal void. This can be addressed by inserting the distal row of pegs first, allowing the free osteo-chondral fragment to rest on the supporting pegs and then impact it with an elevator [20]. These complex fractures gain from direct visualisation and accurate reduction, but the surgeon ought to have at least one assistant who preferably should be experienced in arthroscopy-assisted procedures. The procedure otherwise follows the advice given earlier. It should be noted that they can be extremely demanding even for the experienced surgeon and external or internal bridging fixation is a very reasonable treatment option.
The Metaphyseal Void
Multi-fragmentary fractures are almost always associated with shortening of the radius and/or depressed articular fragments that leave a void after reduction. It is therefore important to consider additional treatment of the metaphyseal void at the end of the procedure, by means of bone graft or bone substitution.
The Arthroscopic Procedure: Exceptional Fracture Types
Partial Volar Fragments
Partial volar fractures can be part of a spectrum of complex injuries involving the stabilising radio-carpal ligaments or represent ligament avulsion fractures. They are easily missed and misunderstood. CT is very useful to plan the procedure. Arthroscopy readily detects them and allows not only exact reduction and fixation but also the diagnosis and treatment of associated injuries.
The so-called teardrop is the U-shaped outline of the volar rim of the lunate facet representing the insertion of the Short Radio-Lunate (SRL) ligament [14]. A displaced ‘teardrop’ fragment will cause radio-carpal instability and can be recognised by an abnormal teardrop angle (75°). The volar ‘teardrop’ fragment tends to rotate dorsally with traction because of ligamentotaxis due to the strong palmar radio-carpal ligaments. Consequently, they need either open reduction and fixation with a temporary K-wire for 3 weeks, a fragment specific small plate, a fragment specific screw or a fixation with a cannulated screw through a limited palmar approach rather than percutaneous fixation due to the delicate anatomy [25, 26]. Alternatively, by decreasing the traction and simultaneously palmarly flexing the joint the fragments might reduce and they can be pinned from the dorsal aspect of the distal radius or from the palmar aspect through a limited palmar approach [2, 27, 28].
Partial Dorsal Fragments
Partial dorsal articular fractures most often involve the lunate facet. They can be difficult to view from dorsal portals unless either a very radial 1-2 portal or a very ulnar 6R portal is established. A volar portal is a very interesting option, provided that the surgeon is experienced in this approach. A small incision is done between the FCR tendon and the radial artery and with careful blunt technique the palmar capsule is penetrated and the arthroscope is inserted [29, 30].
An option is to use a Wissinger rod technique from dorsal, directing the rod between the Radio-Scapho-Capitate ligament (RSC) and the Long Radio-Lunate ligament (LRL) and gently pushing it towards the palmar skin. A small incision is done over the rod and blunt dissection further secures the portal until the trochar is fitted over the rod palmarly and advanced into the joint.
A single K-wire is inserted into the dorsal fragment under fluoroscopic control and the wrist is palmar flexed. Once the reduction is satisfactory after manipulation under arthroscopic guidance, the wire is advanced further after which a cannulated screw fixes the fragment. If the fragment represents a more complex impacted ‘die-punch’ injury then an ulnar fragment specific plate may be considered with or without bone graft behind the impacted fragment.
The Importance of Ulnar Styloid Fractures
The importance of ulnar styloid fractures depends on its relationship to the TFCC, thereby either being part of a destabilising injury to the DRU-joint or not. It is therefore not surprising that there are no studies that show any benefits with repair of ulnar styloid fractures [40]. In fact, ulnar styloid fractures are not always associated with TFCC tears [8–10], or late DRU-joint instability [31–33]. Furthermore, there is no relationship between ulnar styloid fractures or non-union and functional outcome [31–33], which has further been shown in cases with plate fixation [34–39].
Clinical experience suggest that ulnar styloid fragments are stable and ulnar styloid fractures at the base have an increased risk of instability [39] particularly if the fracture is displaced more than 2 mm, especially if the displacement is in radial direction [40]. The fracture in those cases can be fixed with any means, or if comminuted be excised and the TFCC reattached to the fovea of the ulnar head.
Closure and After Care
The pronator quadratus muscle is repaired back to cover the volar locking plate before skin closure and a protective plaster slab is applied, which is changed in 48–72 h to a removable splint before commencing mobilisation with the help of the therapy team. In the absence of scientific evidence for benefit of physiotherapy, experience suggests that physiotherapy starts after 6 weeks in order to restore range of motion and progressive wrist and hand strengthening exercises.
In case of a dorsal rim fracture fixation, 3 weeks of extension blocking splint may be required. A sugar-tong splint to prevent forearm rotation is used when the DRU-joint region needs to be protected as in a TFCC repair.
Extended immobilisation is considered if inter-carpal ligaments have been found, with or without further treatment.
Return to heavy activities is withheld for the first 3 months.
Associated Soft Tissue Injuries in Distal Radial Fractures
Arthroscopy has been pivotal in highlighting the high incidence of soft tissue injuries associated with distal radius fracture, which are frequently missed when the fracture is managed by the conventional methods of treatment (Table 18.1) [8–10, 41]. This is not surprising as the radius may be involved in the greater arch mechanism described by Mayfield in perilunate dislocations [18]. This is further emphasised in non-osteoporotic patients as they more often present with intra-articular fractures caused by a severe, high-energy trauma [42, 43]. In contrast, most fractures in osteoporotic patients are extra-articular and sustained by low energy [44].
Table 18.1
Injuries associated with distal radius fractures
Study | Number and type | % TFCC injury | % SL injury | % LT injury |
|---|---|---|---|---|
Geissler (1996) | 60 (intra-articular) | 49 | 32 | 15 |
Lindau (1997) | 50 (intra- and extra-articular) | 78 | 54 | 16 |
Richards (1997) | 118 (intra- and extra-articular) | 35 (intra) 53 (extra) | 21 (intra) 7 (extra) | 7 (intra) 13 (extra) |
Mehta (2000) | 31 (intra-articular) | 58 | 85 | 61 |
Hanker (2001) | 173 (intra-articular) | 61 | 8 | 12 |
Arthroscopy has become the gold standard in detecting these injuries in addition to being an adjunct in the management of distal radius fractures.
Injuries to the TFCC seem to be the most frequent and are found in around ¾ of the fractures (Table 18.1) [8–10, 45].
The second most frequent ligament injury is to the SL ligament, which is found in between 1/3 and ½ of the cases (Table 18.1) [8–10].
Lunotriquetral (LT) ligament tears are less common and seen in about 1/6 of the fractures [2, 8–10, 45].
Triangular Fibro-Cartilage Complex (TFCC) Injuries
TFCC injuries are the most common associated intra-articular injuries in distal radius fractures in non-osteoporotic patients (Table 18.1) [8–10]. Cadaveric studies have suggested that in order for an ulnar attachment of TFCC to be compromised, the displacement of the distal radius has to be more than 4 mm of radial shortening, down to 0° of radial inclination and a dorsal tilt of minimum 10° [47].
There has been an accepted understanding for the last 10–15 years that associated peripheral tears to the TFCC will cause instability [31–33] with a subsequent worse outcome [31–33]. However, this has recently been contradicted as only one patient had a stabilising procedure due to painful instability in a 15-year prospective longitudinal outcome study of untreated TFCC tears [48].
In the absence of scientific evidence, there is however clinical experience to support the following advice regarding TFCC treatment in association with distal radius fractures:
Central perforation tears (Palmer 1A, [49]) are stable and can be debrided to leave smooth edges with a suction punch, a shaver or a radiofrequency probe. Care should be taken to avoid jeopardising the stability provided by the important palmar and dorsal ulno-radial ligaments. This treatment does not change the overall rehabilitation plan.
Peripheral tears of the TFCC (Palmer 1B [49]) may come with or without associated DRU joint instability. The distal tears may be debrided and possibly sutured back to the capsule and ECU subsheath [50]. The proximal tears cannot be seen at radio-carpal arthroscopy alone, but need reattachment to the fovea of the ulna [50]. The combined tears are diagnosed due to the distal component and should also be reattached [50].
Reattachment can be done with arthroscopy assistance or with an open technique with similar good outcome [51]. Arthroscopically assisted reattachment is done with two or three 2/0 absorbable (PDS) sutures that are passed through the periphery of the TFCC and fixed to the distal ulna, either through drill holes or with any one of the many varieties of TFCC techniques found in the literature. The repair is protected from supination and pronation for 4 weeks, followed by 2–4 weeks in a short-arm cast.
Ulnocarpal ligament tears (Palmar 1C [49]) are very rare [8]. A reinsertion technique directly through the palmar approach in line with the exposure of the critical corner in the intermediate column is the simplest option. This repair should be protected for 4 weeks in relation to the rehabilitation for the fracture.
Radial avulsion tears (Palmar 1D [49]) are uncommon, but may often be associated with a dorso-ulnar fracture fragment. If found in isolation, i.e. true avulsions from the radial insertion site of the ulno-radial ligament, they most likely ought to be reattached [52]. Due to the need for internal fixation of the distal radius fracture, the techniques based on drill holes through the radius are not suitable, but rather with suture anchors with a mini-open approach [53, 54].
Inter-carpal Ligament Injuries
The potential association of inter-carpal ligament injuries to the scapho-lunate (SL) and the luno-triquetral (LT) ligament should be looked upon as part of an incomplete greater arch injury described by Mayfield [18], but without the final dislocation of the lunate. Awareness of this mechanism makes it important to assess these potential associated injuries, where arthroscopic assessment obviously is the best way of detecting and treating them.
The ligament injuries should be classified as partial or complete (Table 18.2).
Grade | Radio-carpal joint | Mid-carpal instability | Step-off | Management |
|---|---|---|---|---|
1 | Haemorrhage of IOL, no attenuation | None | None | Immobilisation |
2 | Incomplete partial or full substance tear, no attenuation | Slight gap (<3 mm) | Midcarpal only | Arthroscopic reduction and pinning |
3 | Ligament attenuation incomplete partial or small full substance tear | Probe can be passed between carpal bones | Midcarpal and radiocarpal | Arthroscopic/open reduction and pinning |
4 | Complete tear | Gross instability, 2.7 mm scope can be passed (drive thru sign) | Midcarpal and radiocarpal | Open reduction and repair |
Based on data from reference [9]
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