DRUJ Injury: Understanding Acute and Chronic Complications

What are the Complications of DRUJ Injury?

Distal Radioulnar Joint (DRUJ) injuries, if not properly diagnosed and managed, can lead to a range of debilitating complications, significantly impacting forearm rotation, wrist stability, and overall upper limb function, often resulting in chronic pain and functional limitations.

Understanding the Distal Radioulnar Joint (DRUJ)

The DRUJ is a pivotal joint located at the wrist, connecting the distal ends of the radius and ulna bones. Unlike the main wrist joint (radiocarpal), the DRUJ's primary role is to facilitate pronation (palm down) and supination (palm up) of the forearm, allowing for the wide range of hand movements essential for daily activities. Its stability is primarily provided by the triangular fibrocartilage complex (TFCC), along with surrounding ligaments and muscle forces. Injury to the DRUJ, often occurring in conjunction with distal radius fractures or isolated trauma, can disrupt this delicate balance.

Immediate (Acute) Complications of DRUJ Injury

Upon initial injury, several acute complications can arise, directly affecting the immediate stability and function of the wrist and forearm.

• DRUJ Instability or Dislocation: The most direct complication. This can be dorsal (ulna dislocates towards the back of the hand) or volar (ulna dislocates towards the palm). It typically presents with a prominent ulna head and a significant loss of forearm rotation.
• Acute Pain and Swelling: Localized pain, especially with forearm rotation, and swelling around the wrist and distal forearm are common.
• Loss of Forearm Rotation: A hallmark of DRUJ injury is the immediate and often severe restriction of pronation and/or supination.
• Associated Fractures: DRUJ injuries frequently occur in conjunction with:
  • Distal Radius Fractures: Particularly Colles' fractures, where the DRUJ may be disrupted even if the ulna itself isn't fractured (Galeazzi fracture-dislocation involves a radial shaft fracture with DRUJ dislocation).
  • Ulnar Styloid Fractures: A common finding with DRUJ instability, often indicating ligamentous injury to the TFCC.
• Neurovascular Compromise (Rare): While uncommon, severe dislocations or associated trauma could potentially compromise nearby nerves (e.g., ulnar nerve) or blood vessels, requiring urgent medical attention.

Long-Term (Chronic) Complications of DRUJ Injury

If acute DRUJ injuries are undiagnosed, inadequately treated, or fail to heal properly, a range of chronic and often more debilitating complications can develop. These can profoundly impact a person's quality of life and functional independence.

• Chronic DRUJ Instability: This is a persistent laxity or subluxation of the joint. Patients may experience:
  • Clicking, Clunking, or Grinding Sensations: Especially during forearm rotation or wrist movements.
  • Feeling of Weakness or "Giving Way": Particularly during activities requiring forearm rotation or gripping.
  • Persistent Pain: Often worse with activity or at the end ranges of motion.
• Chronic Pain: Ongoing pain is a significant long-term complication, which can be localized to the DRUJ, radiate into the forearm, or be diffuse across the wrist. It can be due to instability, arthritis, or soft tissue impingement.
• Limited Range of Motion: Persistent restriction of pronation and supination, which can severely hinder daily tasks like turning doorknobs, using tools, or even eating. Wrist flexion/extension may also be affected secondarily.
• DRUJ Arthrosis (Osteoarthritis): Chronic instability or malalignment places abnormal stress on the joint cartilage, leading to its gradual degeneration. This results in:
  • Progressive Pain and Stiffness: Worsening over time.
  • Crepitus: A grinding sensation during movement.
  • Loss of Joint Space: Visible on X-rays.
• Ulnar Impaction Syndrome: If the DRUJ injury leads to a relative lengthening of the ulna compared to the radius (positive ulnar variance), the ulna can impinge on the carpal bones (lunate and triquetrum) and the TFCC, causing pain and degenerative changes.
• Distal Ulna Impingement: Soft tissue structures (e.g., TFCC remnants, synovium) can become entrapped within the DRUJ, causing pain and mechanical symptoms.
• Nonunion or Malunion of Associated Fractures: If accompanying fractures of the radius or ulna heal incorrectly, it can lead to persistent DRUJ instability, pain, and functional deficits.
• Complex Regional Pain Syndrome (CRPS): Although rare, severe wrist injuries, including those involving the DRUJ, can trigger CRPS. This is a chronic pain condition characterized by severe pain, swelling, skin changes, and functional impairment disproportionate to the initial injury.
• Grip Weakness: Pain, instability, and muscle inhibition can significantly reduce grip strength, impairing the ability to perform tasks requiring firm grasping.
• Functional Limitations and Disability: The cumulative effect of pain, instability, and limited range of motion can severely impact a person's ability to participate in work, sports, and activities of daily living, leading to significant disability.

Factors Contributing to Complications

Several factors can increase the risk of developing these complications:

• Severity of Initial Injury: More severe ligamentous tears or bony involvement.
• Delayed Diagnosis: Missing the DRUJ injury initially, leading to delayed treatment.
• Inadequate Initial Treatment: Insufficient reduction of dislocation or improper immobilization.
• Poor Rehabilitation: Lack of appropriate physical therapy to restore strength, stability, and range of motion.
• Associated Injuries: Concurrent nerve damage or other fractures.

The Importance of Early Diagnosis and Comprehensive Management

Given the critical role of the DRUJ in upper limb function, any suspected injury warrants a thorough clinical and imaging evaluation. Early and accurate diagnosis, followed by appropriate surgical or non-surgical intervention and a structured rehabilitation program, are paramount to minimizing the risk of these debilitating long-term complications and optimizing functional outcomes. Neglecting a DRUJ injury can lead to a cascade of problems that are far more challenging to treat in their chronic phase.