Distal Radius Fracture fixation , volar approach with Synthes® 2.4 mm Variable Angle locking LCP

The tendon of Flexor carpi radialis (FCR) is palpated on the volar aspect of the distal forearm and marked. An extended volar Henry approach is used for this procedure and is marked with a longitudinal incision overlying the FCR tendon.
Note: The palmar cutaneous branch of the median nerve arises approximately 5 cm above the wrist crease and travels on its radial aspect. It traverses superficial to the flexor retainculum to enter the palm and supply the skin over the thenar eminence. This is crucial to preserve if the incision is planned to cross the wrist crease.

The skin is incised with a No. 10 blade along the previously marked line. The FCR sheath containing the tendon lies just underneath the skin incision. There are usually subcutaneous veins travelling transversally over the sheath which are cauterized and divided.
Note: The anatomy may be distorted following swelling and bruising in a significantly displaced fracture. If there are any doubts, the tendons of FCR and Palmaris Longus should both be exposed to guide the appropriate plane of dissection.

The classical Henry approach advises to proceed by dividing the FCR sheath, retracting the tendon and proceeding through the bed of FCR. However, I find that this devitalizes the exposed segment of the tendon. As a result, I have modified the approach. I divide the fascia on the radial edge of the FCR tendon, preserving its sheath.

The fascia is divided in line with the skin incision. Note that the sheath of Flexor Carpi Radialis is preserved.

The tendon is then retracted ulnarwards and a self-retaining retractor used. The radial vessels remain in the flap on the radial side of the approach and are therefore preserved. The exposure now reveals the Flexor Pollicis Longus (FPL) tendon to the thumb.

The FPL tendon is retracted ulnarwards. This now reveals the flat muscle belly of the Pronator Quatratus (PQ) with its transversely oriented fibres. Note that this is the only muscle in the distal forearm with such orientation of the fibres.

The “watershed line” is now marked at the distal edge of the Pronator Quadratus. This overlies the bony ridge in the distal radius just proximal to the radiocarpal joint. The radius dips volarwards beyond this line. Application of the volar plate distal to this line puts the flexor tendons (especially the FPL tendon) at risk of attrition and delayed rupture.

The Pronator Quadratus is incised in an L-shaped pattern; with the longitudinal limb along its radial border and the transverse limb along the “watershed line”. This will allow its elevation from the underlying distal radius.
Note that the radial vessels are protected in the radial flap while the median nerve is protected on the ulnar side of the FCR tendon.

The muscle is elevated with a combination of knife and periosteal elevator to reveal the distal radius and fracture. It is very important to expose the entire distal radius – especially its ulnar border at the distal radioulnar joint. Radially, the brachioradialis may need to be elevated off the radial styloid to facilitate reduction of this fragment.
The proximal extent of the exposure needs to accommodate the length of the plate. Its distal extent should preserve the radio-carpal ligaments.

The fracture is always impacted and requires disimpaction to regain the radial length.
The fracture fragments are mobilised with intra-focal dissection using blunt elevators. This allows for the fragments to be realigned. If there is a depression of the articular segment, this can be elevated through the intra-focal approach as displayed in this picture. the reduction is confirmed using an image intensifier.
Note: I have used a Homan’s retractor along the ulnar edge of the distal radius.

The Synthes® 2.4 mm Variable Angle LCP two-column distal radius set will be used for this case. The set contains templates for the right and left wrist plates. There are guides for fixed angle and variable angle locking screws.

The fracture is reduced and can sometimes be temporarily stabilised with K wires. I have not used K wires for this particular case. The template from the set is utilized to confirm the size of the plate. It is important to take a plate wide enough to incorporate the radial and ulnar fragments of the distal radius with the distal row of screws. The plate should not overhang the watershed line distally. It should also not protrude beyond the radial and ulnar borders of the distal radius. The length of the plate should allow for 2-3 screws in the proximal fragment.

The appropriately sized plate is chosen. This particular plate can accommodate 7 screws (5+ 2) in the distal fragment and 2 screws in the proximal fragment. Note that the distal screw holes are staggered in line. All the distal screw holes are locking (fixed angle or variable angle). The proximal screw holes allow the option of locking or non-locking cortical screws. Note the oval hole in the proximal limb of the plate that allows for fine-tuning of the radial length after the initial application of the plate.
Also note the presence of separate holes to allow temporary stabisation of the plate onto the bone with K wires if required.

A fixed-angle locking guide is screwed into one of the distal holes in the plate, which is then applied to the distal radius. The distal edge of the plate should be in complete contact with the reduced distal fragment. Note that the proximal edge of the plate is kept elevated off the bone for this part of the procedure. This will allow me to regain the volar tilt at the later part of the procedure when the proximal screws are applied.
It is important here to be aware of the methods of fracture reduction in distal radius. These are:
Direct – where the fragments are directly reduced under vision and may or may not be temporarily stabilized with K wires.
Indirect – where the fragments are realigned into position with manipulation of the plate.
I will be using a combination of both these techniques for the reduction and stabilization of this complex comminuted fracture.

A pilot hole is drilled through the locking guide with a 1.8 mm drillbit. It is important to be extremely careful when breaching the dorsal cortex with the drill. The extensor tendons lie in very close proximity to the dorsal surface of the bone and are at risk of injury with the drill (Al-Rashid et al 2006). I always keep my fingers on the dorsal surface, which guides me during the drilling process. It also allows me to stabilize the wrist.
There are measurement markings on the locking drill guide to help with choosing the appropriate size of screw. However, you can also use a depth gauge that is separately provided on the set.

The fixed-angle locking screws are green in colour. The cortical non-locking screws are golden. In addition, there are variable-angle locking screws, which are purple in colour and packed separately. The set also provides the option to use variable-angle smooth locking buttressing pins that can be used in extremely osteoporotic bones.

An appropriately sized, green coloured, fixed-angle locking screw is chosen.

The screw is inserted into the previously drilled hole and locked into the plate.

This is a drill guide for the variable locking screw. It accommodates an angulation of the screw within a 30-degree cone around the central axis of the plate hole. This allows for accurate placement of screws into individual fragments.

The tip of the drill guide keys into the cloverleaf design of the plate hole. The funnel of the drill guide allows the drill bit a variation in the angulation (upto 30 degrees). The drill bit can be aimed in any direction within the cone. Image intensifier may be used to confirm the appropriate angle of drilling.

A purple coloured variable-angled locking screw of appropriate size is chosen.

The variable-angled screw is locked into position in the plate. Use additional screws (fixed-angle and variable-angle) in the distal row to fix all fragments in the radial and intermediate columns. It is always useful to check the screw placements and the screw lengths with image intensifier at this stage. It is important to verify that no screw has penetrated the joint. I use standard AP, lateral, inclined lateral and oblique views to confirm this.

The proximal end of the plate is now reduced onto the radial shaft. This method of indirect reduction allows me to correct the dorsal tilt of the distal fragment. It also facilitates reduction of the radial inclination. The oval hole is utilised to drill a pilot hole with a 1.8 mm drillbit using a drill sleeve.

The screw length is measured using the depth gauge provided and an appropriately sized golden cortical screw (2.4 mm) used to fix the plate onto the proximal shaft of the radius.

The plate can be slid proximally or distally on the oval screw hole to fine-tune the reduction.

Reduction should be confirmed on the image intensifier at this stage. All remaining screws can then be inserted.

An inclined lateral view negates the effect of the overhanging radial styloid and brings the articular surface into profile. This is extremely useful to identify any penetration of the articular surface with the distal screws. It also clearly delineates the volar and dorsal rims of the distal radius allowing for accurate visualisation of the fracture reduction.

After confirming radiographic reduction, clinical assessment should be performed. The fracture stability should be confirmed. The wrist should be moved passively through its entire range of motion. Crepitus during radiocarpal movement is an indication of joint penetration with the screws and should be addressed if identified.
The distal radioulnar joint stability is confirmed with a ballottement test done in midprone, full prone and full supine positions of the wrist. If unstable, the ulnar styloid fracture and the Traingular Fibrocartilaginous Complex (TFCC) should be stabilized. The ulnar styloid fragment (with its TFCC attachment) can be fixed using tension band wiring or specially designed hook plates. A TFCC avulsion requires reattachment with a pull through suture or a bone anchor. Fortunately, this is not required in a majority of the cases.

The Pronator Quadratus muscle is now laid back into its normal position. I do not routinely reattach this with sutures. The FPL and FCR tendons are returned back. Note the intact sheath around the FCR tendon.
The fascia is never closed due to the risk of compartment syndrome.

I close the skin wound with interrupted nylon sutures.

I apply nonadherent dressings and protect the wrist in a plaster volar slab. This provides rest and helps with pain relief in the immediate post-operative period. I will remove this in 10 days when the sutures are removed.