DRUJ Stabilization: Masterclass in Intra-Articular Radioulnar Ligament Reconstruction

Alright, fellows, gather around. Today, we're tackling a fascinating and often challenging problem: chronic distal radioulnar joint (DRUJ) instability requiring intra-articular radioulnar ligament reconstruction. This isn't a procedure to be taken lightly; it demands a deep understanding of wrist biomechanics, meticulous surgical technique, and an appreciation for the subtle anatomical nuances. Our goal isn't just to stabilize the joint, but to restore a full, pain-free arc of forearm motion. Let's scrub in.

Understanding the Distal Radioulnar Joint: A Foundation in Anatomy and Pathogenesis

First, let's re-establish our anatomical bearings. The DRUJ is a pivotal joint, allowing the intricate pronation and supination movements of the forearm. It's formed by the articulation of the ulnar head with the sigmoid notch of the distal radius. Crucially, it's not a congruent joint; the sigmoid notch's radius of curvature is typically 50% greater than that of the ulnar head. This inherent incongruity highlights the absolute reliance of the DRUJ on its soft tissue stabilizers.

The primary stabilizers we're focusing on today are the palmar (volar) and dorsal radioulnar ligaments. These are not isolated structures but rather thickenings at the combined junctures of the triangular fibrocartilage articular disc, the DRUJ capsule, and the ulnocarpal capsule. As each radioulnar ligament passes ulnarly, it divides into two distinct limbs:
* The deep or proximal limbs attach directly to the fovea of the ulnar head. This foveal attachment is critical for isometric stability throughout the forearm's rotational arc.
* The superficial or distal limbs attach to the base and midportion of the ulnar styloid.

Beyond these primary ligaments, several other soft tissue structures contribute to DRUJ stability. We have the pronator quadratus muscle, which acts as a dynamic stabilizer, especially in pronation. The extensor carpi ulnaris (ECU) tendon and its sheath also play a role, particularly in dorsal stability, and its integrity is paramount during our approach. The interosseous membrane, extending between the radius and ulna, provides significant longitudinal stability. Finally, the broader DRUJ capsule and the other components of the triangular fibrocartilage complex (TFCC), including the articular disc itself, contribute to overall joint integrity. Remember, true DRUJ instability often requires injury to multiple of these structures.

Pathogenesis of DRUJ Instability

The most common culprit behind DRUJ disruption is a distal radius fracture. Significant changes in radial anatomy, such as angulation greater than 20-30 degrees or radial shortening exceeding 5-7 mm, can lead to DRUJ incongruity, distort the TFCC, and rupture the radioulnar ligaments. Fractures at the base of the ulnar styloid are particularly concerning, as this is where the superficial limbs of the radioulnar ligaments attach. Fractures of the styloid tip, however, are less commonly associated with instability.

Isolated DRUJ dislocations, without an associated fracture, are typically dorsal, resulting from forceful hyperpronation and wrist extension (e.g., a fall on an outstretched hand). Conversely, volar dislocations are less common and usually occur with an injury to the supinated forearm or a direct blow to the ulnar aspect.

Clinical Presentation and Diagnosis

Patients will often present with a history of a fall or a forced rotational injury, followed by ulnar-sided wrist pain, swelling, and a sense of instability. With chronic instability, they may report a distinct "clunk" with forearm rotation, and pain and weakness exacerbated by activities requiring forceful rotation and grip, like turning a screwdriver.

Our physical examination is key. We're looking for:
* Increased passive volar-dorsal translation of the ulna relative to the radius – the classic "piano key" sign. Compare meticulously to the unaffected side.
* Modified press test: Increased depression of the ulnar head on the affected side ("dimple" sign) suggests instability. Pain without increased depression might point more towards a TFCC tear.
* Passive forearm rotation: A painful clunk here indicates gross DRUJ instability. Be careful not to confuse this with subtle ECU subluxation.

Imaging Modalities

Appropriate imaging is non-negotiable for confirming diagnosis and guiding our surgical strategy.
* Radiographs:
* A zero-rotation posteroanterior (PA) view is crucial. This is obtained with the humerus abducted 90 degrees, elbow flexed 90 degrees, and forearm on a flat surface. Look for:
* Displaced fracture at the base of the ulnar styloid.
* A fleck fracture from the ulnar fovea.
* Widening of the DRUJ.
* Greater than 5 mm of acquired ulnar positive variance compared to the contralateral wrist.
* A true lateral radiograph is equally vital. The arm should be at the patient's side, elbow flexed 90 degrees. Remember, even 10 degrees of rotation can obscure true DRUJ alignment. On a true lateral, the lunate, scaphoid proximal pole, and triquetrum should overlap completely, and there should be no space between the triquetrum and pisiform.
* CT Scans: These are invaluable, especially for assessing bony morphology and subtle subluxation.
* Crucially, CT must be performed on both wrists, with images obtained in identical forearm rotation (typically neutral) for direct comparison. This allows us to quantify translation and identify incongruity.
* Consider adding stress views during imaging to unmask subtle instability.

• MRI: With or without intra-articular dye, MRI can detect TFCC tears and provide further detail on soft tissue injuries. It can also assess the shape of the sigmoid notch and overall joint stability.

Nonoperative Management

Before we consider surgery, remember that nonoperative management has its place, especially for mild chronic instability. A course of NSAIDs, a splint limiting forearm rotation, and a targeted forearm strengthening program can be beneficial. In acute distal radius fractures with DRUJ disruption, always reduce and stabilize the fracture first; often, this alone resolves the DRUJ instability. Patients with generalized ligamentous laxity and bilateral DRUJ instability are less predictable surgical candidates, and conservative measures should be exhausted.

Surgical Management: Indications and Preoperative Planning

Our primary indication for intra-articular radioulnar ligament reconstruction is chronic DRUJ instability where the native tissues are inadequate for primary repair of the TFCC. A critical prerequisite for success is a competent sigmoid notch. If the notch is developmentally flat or has a post-traumatic deficiency of either the dorsal or volar rim, we must address this with a sigmoid notch osteoplasty concurrently with the ligament reconstruction. Furthermore, any significant osseous malalignment of the distal radius must be corrected at the time of reconstruction to achieve a good result. Soft tissue reconstruction over substantial bony deformity or existing DRUJ arthritis will inevitably lead to poor outcomes.

Preoperative Planning

Fellows, this is where we lay the groundwork for success.
1. Imaging Review: Meticulously review all imaging studies – radiographs, CT, MRI – for any evidence of osseous deformity (e.g., malunion of a distal radius fracture, ulnar positive variance) or degeneration of the DRUJ articular surfaces. Plan for any necessary corrective osteotomy or sigmoid notch osteoplasty.
2. Graft Selection: The palmaris longus (PL) tendon is our go-to choice due to its consistent anatomy and minimal donor site morbidity. If the PL is absent (which occurs in about 10-15% of the population), or if additional length is needed, alternative graft sources include the plantaris tendon, a strip of the extensor digitorum longus, or most commonly, a strip of the flexor carpi ulnaris (FCU) tendon. Ensure you have a backup plan.
3. Patient Positioning: The patient is positioned supine on the operating table. The affected limb rests on a hand table, allowing full access to the wrist and forearm. We'll need to adjust the hand table and potentially the patient's arm to facilitate graft harvest from the ipsilateral forearm. A well-padded tourniquet is applied to the upper arm.

Step-by-Step Intraoperative Execution: The Masterclass

Now, let's get into the theater. We'll proceed systematically, emphasizing precision and anatomical awareness.

1. Palmaris Tendon Graft Harvest

Our first step is to harvest the autograft. We'll aim for the palmaris longus.

• Identification: Have the patient, if awake, flex their wrist and oppose their thumb and small finger. This will typically make the palmaris longus tendon prominent. If the patient is anesthetized, gently flex the wrist against resistance or palpate carefully. It's one of the most superficial structures at the distal wrist crease, lying just ulnar to the flexor carpi radialis tendon.
  

  
  
  

* Incision: Make a single 1-cm transverse incision at the proximal volar wrist crease directly overlying the identified PL tendon.

Surgical Warning: If harvesting an FCU strip, use the same volar incision. Dissect down to the FCU tendon, identify its ulnar border, and use a tendon stripper to harvest a strip while carefully protecting the ulnar neurovascular bundle which lies immediately radial to the FCU tendon.

2. Dorsal Approach to the DRUJ

Now, let's move to the main event – exposing the DRUJ dorsally.

• Skin Incision: Make a 5-cm longitudinal skin incision centered over the DRUJ, positioned between the fifth and sixth extensor compartments. This interval is relatively safe, minimizing disruption to important structures.
  

  
  
  

* Compartment Dissection: Carefully incise the retinaculum overlying the fifth extensor compartment. Retract the extensor digiti minimi (EDM) tendon radially.
* ECU Sheath Preservation: This is critical, fellows. The ECU tendon sheath must not be disrupted during this approach. The ECU and its sheath contribute significantly to DRUJ stability, and an intact sheath helps maintain the tendon's mechanical advantage.
* Capsulotomy: Once the DRUJ capsule is exposed, make an L-shaped capsulotomy.
* One limb of the "L" should be in line with the sigmoid notch, extending radially.
* The other limb should be just proximal and parallel to the TFCC, extending ulnarly.
* The ECU tendon sheath marks the ulnar limit of this capsulotomy. Do not extend beyond it.

3. Bone Tunnel Placement

This is where we create the precise pathways for our graft, mimicking the native radioulnar ligaments.

• Radial Tunnel Preparation:
  • Using careful subperiosteal dissection, elevate the soft tissue from the dorsal edge of the sigmoid notch for several millimeters. This exposes the bone for tunnel placement.
  • Identify the appropriate starting point for the radial tunnel: it should begin several millimeters proximal to the lunate fossa and approximately 5 mm radial to the articular surface of the sigmoid notch. This placement is crucial to avoid violating the articular cartilage and to ensure isometric graft placement.
  • The tunnel should be oriented parallel to the articular surfaces of both the sigmoid notch and the lunate fossa.
  • Drive a guidewire for a 3.5-mm cannulated drill bit from dorsal to volar through the radius, aiming for the volar aspect of the radius, distal to the pronator quadratus insertion.
  • Fluoroscopy is mandatory here, fellows. Obtain both AP and lateral views to confirm precise guidewire placement, ensuring it's not too close to the articular surface and is exiting in a safe volar location.
    

    
    
    

* Once confirmed, use the 3.5-mm cannulated drill bit to create the radial tunnel. Irrigate to cool the bone.
* Ulnar Tunnel Preparation:
* Elevate the ulnar flap of the DRUJ capsulotomy to expose the ulnar head and neck, again, being scrupulous not to injure the ECU tendon sheath.
* Now, we need to access the ulnar fovea. Flex the wrist and pronate the forearm to help retract the TFCC remnant and provide better visualization.
* The ulnar bone tunnel will travel from the ulnar fovea to exit on the lateral ulnar neck, just volar to the ECU tendon.
* Retrograde Technique (Preferred): Pass a guidewire retrograde from the ulnar fovea (identified by its characteristic depression) to exit on the lateral ulnar neck. Confirm this position with fluoroscopy.
* Antegrade Technique (Alternative): If exposure of the fovea is inadequate despite wrist flexion, you may create the tunnel antegrade from the lateral ulnar neck to the fovea. If using this approach, be extremely careful to protect any remaining TFCC tissue and the ulnar carpus with a blunt probe or elevator as the drill exits.

Surgical Pearl: If a corrective osteotomy of the radius is planned, it is generally easier to create the bone tunnels before performing the osteotomy. However, the tendon graft should not be placed or tensioned until the osteotomy is completed and stabilized.

4. Graft Passage

This is a multi-step process requiring careful coordination and visualization.

• Volar Exposure for Radial Tunnel Exit:
  • Make a second exposure to visualize the volar aspect of the radial bone tunnel. This involves a 3-cm longitudinal incision extending proximally from the proximal wrist crease, slightly radial to the previous graft harvest incision.
  • Carefully dissect down between the ulnar neurovascular bundle (ulnar artery and nerve) and the finger flexor tendons to reach the volar surface of the radius. Protect these vital structures meticulously.
    

    
    
    

* Passing Graft through Radius:
* From the dorsal wound, pass a suture passer (or a curved hemostat with a suture) through the radial bone tunnel from dorsal to volar.
* In the volar wound, grasp one end of your harvested tendon graft (which we've pre-sutured with a leading suture, of course) and pull it back through the distal radius tunnel from volar to dorsal.

Surgical Warning: Throughout the graft passage, always be mindful of surrounding neurovascular structures, especially the ulnar nerve and artery volarly, and the dorsal sensory branch of the ulnar nerve dorsally. Blunt dissection and careful retraction are your best friends.

5. Graft Tensioning and Fixation

This step determines the ultimate stability and functional outcome.

• Positioning: Hold the forearm in neutral rotation. Manually compress the DRUJ to ensure optimal joint reduction and contact.
• Tensioning: With the DRUJ compressed and forearm in neutral, pull both graft limbs taut. You want firm, but not excessive, tension. The goal is to provide stability without restricting normal motion.
• Fixation: While maintaining firm tension in the graft, create a half-hitch knot against the dorsal aspect of the ulnar neck. This allows for initial provisional fixation.
  

  
  
  

6. Closure and Post-Fixation Assessment

• Capsular Repair: Close the L-shaped capsulotomy carefully with absorbable sutures. This helps reinforce the reconstruction.
• Retinacular and Subcutaneous Closure: Close the extensor retinaculum, subcutaneous layers, and skin in a standard fashion.
• Final Stability Check: Before applying the dressing, gently range the wrist and forearm to confirm stability throughout pronation and supination while ensuring no undue restriction of motion.

Pearls and Pitfalls

💡 Pearls and Pitfalls

• Preoperative Planning is Paramount: Don't underestimate the value of detailed imaging review. Identifying a flat sigmoid notch or significant osseous malalignment before surgery dictates additional steps like osteoplasty or corrective osteotomy, which are critical for success.
• Graft Harvest Confirmation: Always confirm the identity of the palmaris longus with a shepherd's hook and traction. Harvesting the wrong tendon is a preventable error.
• ECU Sheath Integrity: This is a recurring theme for a reason. Preserve the ECU tendon sheath at all costs during the dorsal approach and ulnar tunnel creation. Its disruption can lead to iatrogenic ECU subluxation or further instability.
• Fluoroscopy for Tunnels: Never guess on bone tunnel placement. Use fluoroscopy liberally to confirm guidewire and drill bit positions, especially to avoid articular cartilage violation.
• Neurovascular Protection: The ulnar neurovascular bundle volar to the DRUJ is vulnerable during volar dissection and graft passage. Use blunt dissection and careful retraction. Similarly, be aware of the dorsal sensory branch of the ulnar nerve during the dorsal approach.
• Isometric Placement: The goal is to recreate the isometric properties of the native ligaments. Proper tunnel placement, particularly the foveal attachment on the ulna and the radial tunnel's relationship to the sigmoid notch, is key. Incorrect placement can lead to graft laxity in some arcs of motion or overtightening in others.
• Graft Tensioning: This is an art as much as a science. Too loose, and instability persists. Too tight, and you restrict motion and risk joint stiffness or even iatrogenic subluxation in the opposite direction. Neutral forearm rotation with manual DRUJ compression is the ideal position for tensioning.
• Salvage for Failed Reconstruction: If a reconstruction fails due to persistent instability, reassess the underlying issues. Was there residual bony deformity? Was the graft placement non-isometric? Is there significant arthritis? Options may include revision reconstruction (perhaps with a different graft source or technique), DRUJ arthrodesis (Sauvé-Kapandji procedure), or partial/total ulnar head resection (Darrach procedure), depending on the patient's symptoms and joint status.

Postoperative Management and Rehabilitation

Our job isn't done when the last suture is tied. Postoperative care is integral to achieving our functional goals.

Immediate Postoperative Period (0-6 weeks)

• Immobilization: The wrist will typically be immobilized in a sugar tong splint or a long arm cast for 4-6 weeks, holding the forearm in neutral rotation. This protects the healing graft and allows initial soft tissue integration.
• Pain Management: Standard multimodal pain management.
• Elevation: Encourage elevation of the hand to minimize swelling.
• Finger ROM: Active range of motion for the fingers and thumb should begin immediately to prevent stiffness.
• DVT Prophylaxis: Standard DVT prophylaxis protocols will be followed.

Early Rehabilitation (6-12 weeks)

• Splint Removal & Gradual Mobilization: After 4-6 weeks, the cast is removed. The patient will transition to a removable wrist brace that limits forearm rotation, or a custom-molded orthosis.
• Physical Therapy: Initiate gentle, protected active and passive range of motion exercises for the wrist and forearm.
  • Focus initially on restoring pronation and supination within pain limits, gradually increasing the arc.
  • Begin with gentle wrist flexion/extension and radial/ulnar deviation.
  • Avoid forceful gripping or heavy lifting.
• Scar Management: Begin scar massage and desensitization.

Advanced Rehabilitation (12+ weeks)

• Strengthening: Gradually introduce progressive strengthening exercises for the wrist and forearm musculature. This includes isometric, then isotonic exercises.
• Functional Activities: Incorporate functional activities that mimic daily tasks.
• Return to Activity: Return to sport or heavy labor is typically delayed until 4-6 months, depending on the patient's progress and the demands of their activity. This should be a gradual, supervised return.

Complication Management

• Wound Dehiscence/Infection: Manage with local wound care, antibiotics, and débridement if necessary. Early recognition is key.
• Hardware Failure (if osteotomy performed): May require revision surgery.
• Persistent Instability: If instability persists despite adequate rehabilitation, re-evaluate with imaging and clinical examination. Consider the pearls and pitfalls discussed earlier. Revision surgery or alternative salvage procedures (e.g., DRUJ arthrodesis) may be necessary.
• Stiffness: Aggressive physical therapy, including dynamic splinting, may be required. In rare cases, surgical release of adhesions may be considered, but this is avoided if possible.
• Nerve Injury: Neurop

REFERENCES

OUTCOMES
- Patients with a deficient sigmoid notch are more likely to experience recurrent instability if the deficits are not corrected.

• Most patients experience decreased pain and improved strength and stability while maintaining near-normal range of motion. However, full recovery may require 6 to 9 months.

• The described technique effectively restored stability in 12 of 14 patients while providing about 85% of the strength and range of motion of the contralateral unaffected side. 2

The two failures resulted from deficiencies of the sigmoid notch that were not recognized preoperatively.

• Teoh and Yam 12 reported similar results, with restoration of stability in seven of nine patients using a similar reconstructive method.

• Adams BD. Effects of radial deformity on distal radioulnar joint mechanics. J Hand Surg Am 1993;18A:492–498.

• Adams BD, Berger RA. An anatomic reconstruction of the distal radioulnar ligaments for posttraumatic distal radioulnar joint instability. J Hand Surg Am 2002;27A:243–251.

• Ekenstam F. Anatomy of the distal radioulnar joint. Clin Orthop Relat Res 1992;275:14–18.

• Kihara H, Palmer AK, Werner FW, et al. The effect of dorsally angulated distal radius fractures on distal radioulnar joint congruency and forearm rotation. J Hand Surg Am 1996;21A:40–47.

• Kihara H, Short WH, Werner FW, et al. The stabilizing mechanism of the distal radioulnar joint during pronation and supination. J Hand Surg Am 1995;20A:930–936.

• Lester B, Halbrecht J, Levy IM, et al. “Press test” for office diagnosis of triangular fibrocartilage complex tears of the wrist. Ann Plast Surg 1995;35:41–45.

• Lindau T, Hagberg L, Adlercreutz C, et al. Distal radioulnar instability is an independent worsening factor in distal radial fractures. Clin Orthop Relat Res 2000;376:229–235.

• May MM, Lawton JN, Blazar PE. Ulnar styloid fractures associated with distal radius fractures: incidence and implications for distal radioulnar joint instability. J Hand Surg Am 2002;27A:965–971.

• Mino DE, Palmer AK, Levinsohn EM. Radiography and computerized tomography in the diagnosis of incongruity of the distal radio-ulnar joint: a prospective study. J Bone Joint Surg Am 1985;67A:247–252.

• Pirela-Cruz MA, Goll SR, Klug M, et al. Stress computed tomography analysis of the distal radioulnar joint: a diagnostic tool for determining translational motion. J Hand Surg Am 1991;16A:75–82.

• Stuart PR, Berger RA, Linscheid RL, et al. The dorsopalmar stability of the distal radioulnar joint. J Hand Surg Am 2000;25A: 689–699.

• Teoh LC, Yam AKT. Anatomic reconstruction of the distal radioulnar ligaments: long-term results. J Hand Surg Br 2005;30B: 185–193.

• Tolat AR, Stanley JK, Trail IA. A cadaveric study of the anatomy and stability of the distal radioulnar joint in the coronal and transverse planes. J Hand Surg Br 1996;21B:587–594.