Ulnar-Sided Wrist Pain and Swelling: Causes and Treatment
Primary Causes
The most common causes of ulnar-sided wrist pain and swelling are triangular fibrocartilage complex (TFCC) tears, lunotriquetral ligament injuries, and ulnocarpal impaction syndrome 1. These three entities account for the majority of ulnar-sided wrist pathology and often present with overlapping clinical features 1, 2.
Anatomic Framework for Diagnosis
Using the ulnar styloid as a reference point, pathology can be organized by "storey" 3:
- Lower storey (DRUJ level): Distal radioulnar joint (DRUJ) instability, ulnar styloid fractures, extensor carpi ulnaris (ECU) tendinitis or subluxation 3
- Intermediate storey (radiocarpal level): TFCC tears (central disc or peripheral attachments), ulnocarpal impaction syndrome 3
- Upper storey (midcarpal level): Lunotriquetral ligament tears, pisotriquetral arthritis, hamate fractures 3
Additional Common Causes
- Ulnar tunnel syndrome (Guyon's canal): Compression of the ulnar nerve at the wrist, most commonly from ganglion cysts, but also from fractures, inflammatory conditions, neoplasms, vascular anomalies, or aberrant musculature 4
- Acute trauma: Bone fractures (ulnar styloid, hamate hook, triquetrum) and ligament sprains/tears 5
- Chronic overuse injuries: Particularly in athletes involved in baseball, racket sports, golf, wrestling, and activities requiring strong grip and forearm rotation 5
Diagnostic Approach
Initial Imaging
Obtain three-view wrist radiographs (posteroanterior, lateral, and oblique) immediately to exclude fractures and assess ulnar variance 6, 7. Standard projections allow assessment of alignment, joint spaces, impaction syndromes, static instability, chronic fractures, and soft tissue swelling 7.
Advanced Imaging When Radiographs Are Normal or Nonspecific
For suspected TFCC or ligament injury, MRI without contrast is the appropriate next study 6. Key performance characteristics:
- High accuracy for central TFCC disc lesions using high-resolution fast spin-echo or 3D gradient-recalled sequences 6
- 3.0T MRI may be more accurate than 1.5T for TFCC lesions 6
- Fair sensitivity only for peripheral TFCC attachments and ulnar disc attachments with non-contrast MRI 6
MR arthrography has higher sensitivity than standard MRI for complete and incomplete lunotriquetral ligament tears 6. This is particularly important when ligamentous injury is suspected but standard MRI is equivocal.
CT arthrography is an alternative with similar or superior accuracy to MR arthrography for TFCC and intrinsic ligament lesions, with nearly 100% sensitivity and specificity for both scapholunate and TFCC lesions 6.
Ultrasound Considerations
Ultrasound is useful for diagnosing ganglion cysts and vascular anomalies, and can localize the level of compression in ulnar tunnel syndrome 4. Given the superficial location of wrist structures, high-frequency (10-15 MHz) linear transducers allow dynamic examination 7.
Electrodiagnostic Studies
Nerve conduction studies are indicated when neurologic symptoms suggest ulnar tunnel syndrome to confirm diagnosis and exclude proximal compression 4.
Treatment Principles
Conservative Management for TFCC Injuries
Immobilization in neutral wrist and forearm position for 4 weeks is recommended 6. This is followed by:
Surgical Indications
Arthroscopic foveal repair with suture anchor for peripheral TFCC tears (Palmer 1B) with foveal detachment restores anatomic attachment critical for DRUJ stability 6. This is the gold standard for peripheral tears that fail conservative management.
Ulnar Tunnel Syndrome Management
Mild symptoms can be managed non-operatively with activity modification and splinting 4. Surgical exploration and decompression is the gold standard treatment for neurocompressive causes with largely good outcomes 4.
Critical Clinical Pearls
Red Flags Requiring Urgent Investigation
- Night pain or pain at rest suggests inflammatory or neoplastic process 8
- Mechanical symptoms (locking, catching) indicate intra-articular pathology requiring advanced imaging 8
- Progressive neurologic symptoms (paresthesias, weakness, muscle atrophy) require immediate nerve evaluation 4
Common Diagnostic Pitfalls
The ulnar side of the wrist has been referred to as the "black box" of the wrist because of overlapping anatomy, complex differential diagnosis, and varied treatment outcomes 1. The most common error is assuming all ulnar-sided pain is TFCC-related 3.
Failing to obtain initial radiographs to rule out osseous pathology is a critical mistake, as fractures and ulnar variance abnormalities fundamentally change management 8, 7.
Distinguishing stable versus unstable wrist pathology, with or without arthritis, is essential as this guides management of DRUJ-related pain 3.