Keywords
distal radioulnar joint - instability - distal oblique bundle - reconstruction
Introduction
Instability of the distal radioulnar joint (DRUJ) is one of the major unsolved problems
in hand surgery. Throughout history, numerous techniques have been described to increase
stability and relieve pain. These techniques have ranged from repair of the triangular
fibrocartilage complex (TFCC) to salvage procedures, such as Darrach, Sauvé-Kapandji,
or arthroplasties in subjects with degenerative alterations.[1]
Anatomically speaking, this is a very complex joint, which is stabilized by a number
of structures, including the articular congruence of the sigmoid fossa of the radius
with the ulnar head, the TFCC, the pronator quadratus and extensor carpi ulnaris muscles,
and the distal oblique bundle (DOB). The DOB has gained importance in recent years.
It is a ligamentous reinforcement at the most distal portion of the interosseous membrane,
present in 40%, 50% or even 70% of the population. It arises from the distal 1/6 of
the ulnar diaphysis, attaching itself to the lower dorsal edge of the sigmoid fossa
of the radius; it influences DRUJ stability in all rotational positions of the forearm.
Under normal circumstances, it is a secondary stabilizer of the DRUJ; however, when
the TFCC is injured, it becomes an important joint stabilizer both in palmar and dorsal
deviations.[2] As such, in recent years, several techniques have been developed in an attempt to
reconstruct this ligamentous reinforcement.
The present paper aims to describe a simple, reproducible technique for DOB reconstruction
with an extensor carpi radialis longus (ECRL) hemitendon, increasing DRUJ stability.
Surgical Technique and Clinical Cases
The technique described is indicated in patients with DRUJ instability with irreparable
TFCC or previously unsuccessful TFCC repair with no joint degeneration.
Surgical Technique
Ultrasonography was used before surgery to identify the distal level of the ECRL tendon
and the myotendinous junction at the proximal level.
An arthroscopy was performed to confirm the presence of an irreparable TFCC rupture
and the absence of degenerative lesions.
Under ischemia and with the forearm in prone position on the surgical table, an incision
was performed at the dorsoradial aspect of the wrist at the level of the styloid process
of the radius, where the ECRB was identified using ultrasound; next, dissection and
reference (with a vessel loop) were performed. The tendon was marked between 3.5 mm
and 4 mm on its radial side and divided with a #11 scalpel, grasping the radial hemitendon
with a wire loop.
Next, a new 2-cm incision was performed at the level of the proximal mark until the
ECRL was opened at its myotendinous junction. A retriever (arthroscopic Grasper forceps)
was introduced through this opening in an antegrade manner until it came out at the
distal incision. The wire loop was retrieved and extracted through the proximal incision,
and then pulled proximally to section the tendon longitudinally. The hemitendon was
sectioned at the proximal level and recovered in its entire length, being pulled through
a distal approach ([Figure 1a]).
Fig. 1 Schematic representation of the technique. (A) Extensor carpi radialis longus (ECRL) hemitendon graft. (B) Bone tunnels drilled under percutaneous guidance. (C) ECRL hemitendon passing through the tunnels. (D) Plasty fixation with interference screws.
The next step was to perform a bone tunnel in the radius and in the distal third of
the ulnar diaphysis according to the previous anatomical descriptions proposed in
the literature. This procedure was aided by a specific percutaneous C-guide (Arthrex,
Naples, Florida, US) and performed under fluoroscopic control. To calculate guide
obliquity, a 50° angle was measured with a goniometer to place the distal branch parallel
to the distal epiphysis of the radius ([Figure 1b]). First, a 2.4-mm Kirschner wire was passed through the guide in an oblique direction
from the radius styloid to the proximal limit of the radial sigmoid fossa, and it
was drilled (with a 4-mm cannulated drill) until reaching the second cortical layer
of the radius, avoiding iatrogenic injury to the interosseous membrane. The same process
was performed at the ulna, passing a needle under fluoroscopic control, followed by
drilling.
The hemitendonplasty was prepared with a 4/0 non-absorbable braided suture, according
to the Krakow technique, placed on its free end. The suture was performed from the
radial to the ulnar tunnels with a passer (wire loop, suture lasso etc.), and pulled
to recover the tendon end at the ulnar level.
The plasty was fixed at the levels of the radial and ulnar tunnels using a 4 × 10-mm
biotenodesis screw with the forearm in 60° of supination ([Figure 1c] and [1d]). Finally, the distal hemitendon was sectioned at its attachment to the radius,
leaving the remaining tendon independent from the ECRL.
The wound was closed in planes and the arm was immobilized with a brachiopalmar splint
in neutral prone supination for 4 weeks, followed by an antebrachial splint for another
2 weeks. Next, elbow flexion-extension exercises were started, avoiding prone supination.
Full range of motion was allowed at 6 weeks. Strengthening exercises were restricted
until the 12th week, when joint balance was complete and there was no DRUJ instability.
Clinical Cases
We present two cases in which this surgical technique has been used.
The first case (28-year-old male, dominant right hand) was a polytraumatized patient
who suffered a DRUJ dislocation that was diagnosed 4 weeks after admission ([Figure 2]). Surgical reduction of the DRUJ was performed through a dorsal approach to the
wrist. In this case, the DRUJ was shown to be unstable, with irreparable TFCC damage.
Fig. 2 Distal radioulnar luxation. (A-B) Volar dislocation of the ulnar head in anteroposterior and lateral radiographs.
(C-D) Magnetic resonance imaging (MRI) and computed axial tomography (CAT) scans.
The second patient (42-year-old female, dominant right hand) had DRUJ instability
at direct TFCC repair under arthroscopy ([Figure 3]). The patient still presented pain, and the TFCC rupture was diagnosed on the same
magnetic resonance imaging (MRI) scan. During the intervention, an irreparable Palmer
type-Ib tear was observed.
Fig. 3 Reconstruction of the distal oblique bundle. (A-B) Intraoperative images. (C) Postoperative radiograph.
Both patients were evaluated with more than 1 year of evolution (at 17 and 13 months
respectively), with very satisfactory functional outcomes and a stable DRUJ in the
entire range of motion. Patient 1 had a joint balance of 75° in supination and 70°
in pronation, with full flexion-extension, whereas patient 2 presented 65° in supination
and 70° in pronation, with full flexion-extension. The visual analog scale (VAS) score
for pain was 1 in the first case and 2 in the second case. Both subjects returned
to their usual activities.
Discussion
There are numerous indirect or direct radioulnar reconstruction techniques, and most
of them can restrict forearm rotation.
The DOB is inconsistent, being found in 40% of the population, and it influences DRUJ
stability in all positions of forearm rotation.[3] Its importance has been described in distal radial fractures with TFCC rupture,
since it maintains DRUJ stability when the radial height is corrected and DOB tension
accounts for DRUJ reduction.[4] Due to its disposition, some authors considered it a secondary DRUJ stabilizer,
with special importance when primary DRUJ stabilizers, such as the TFCC and the distal
radioulnar ligaments, are injured.[5]
Several DOB reconstruction techniques have been described recently. In 2013, Riggenbach
et al.[6] performed an anatomical study in cadavers comparing the reconstruction of distal
radioulnar ligaments and DOB reconstruction. The Adams technique was used for the
reconstruction of the radioulnar ligaments, whereas the DOB was replaced with a palmaris
longus or an extensor carpi radialis brevis (ECRB) hemitendon graft; both techniques
achieved similar functional outcomes; in addition, DOB reconstruction had no better
functional outcome when associated with a supplementary Adams technique. In 2015,
the same authors published their first clinical cases of DOB reconstruction with satisfactory
outcomes, tensioning the plasty in 60° of supination and fixing it using a Pulvertaft
suture. These patients were operated on with conventional approaches. We believe that
arthroscopy or minimally-invasive surgery, such as the one we herein presented, must
be used, since open procedures increase the risk of joint stiffness.
Brink and Hannemann[7] published a reconstruction technique with radial and ulnar tunnels in the anatomical
position of the DOB using the palmaris longus tendon or the hemitendon of the flexor
carpis radialis and fixing it in maximum supination with an interferential biotenodesis
screw, with good clinical outcomes in 14 subjects.
De Vries et al.[8] published a study performed in cadavers of a minimally-invasive technique using
a button-type suspension system (Tight-Rope, Arthrex) towards the DOB, with good DRUJ
stability.
In our opinion, the use of a specific guide reduces the aggression to soft tissues
and increases procedural reproducibility and safety. Our technique spares from injury
neurovascular structures close to the interosseous membrane, the space of Parona or
the volar components of the forearm. The use of the radial hemitendon of the ECRL
can be a good alternative, with low morbidity for DOB reconstruction; it is easy to
obtain and handle by tightening it before its distal tenotomy. It is indicated in
cases of failure or impossibility of TFCC repair, to support a non-acute TFCC injury,
and in wrist fractures with distal radioulnar instability after osteosynthesis.
Recently, articles such as the one by Low et al.[9] reported similar outcomes from the reconstruction of radioulnar ligaments and of
the DOB.
Due to its length, the tendon[10] may be used in cases of longitudinal instability of the forearm, also repairing
the middle oblique band of the interosseous membrane, in addition to the DOB.
