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OSTEOARTHRITIS SCAPHOTRAPEZIAL TRAPEZOID (STT JOINT)

Introduction

Scaphotrapezial trapezoidal (STT) osteoarthritis (OA) is a common degenerative disease of the wrist, specifically at the site of articulation among the scaphoid, trapezium, and trapezoid. Dorsal intercalated segment instability (DISI) may coexist with STT joint OA. Several studies also have demonstrated a strong association between STT and thumb carpometacarpal (CMC) joint OA, and an association with capitolunate OA (although capitolunate OA may be a secondary effect of chronic DISI). Therefore, STT joint OA is not always an isolated disorder. In fact, CMC and STT joint OA may develop concomitantly.

Pathophysiology

  • Studies have linked the following to STT OA:
    • Lunate morphology
    • DISI
    • Thumb CMC or trapeziometacarpal OA

Related Anatomy

  • The capitate-trapezium ligament originates from the trapezium and inserts into the volar waist of the capitate and deepens the socket of the STT joint.
  • The scaphotrapezial and trapeziotrapezoid volar ligaments stabilize the joint.
  • The dorsolateral STT ligament stabilizes and links the joint to the rest of the midcarpus.
  • The function of the STT joint is to allow transfer of load from the thumb and radial hand to the scaphoid, capitate, and other carpal bones.
  • STT OA is often associated with OA of the trapeziometacarpal joint, but it can be an isolated pathology.  

Incidence and Related Conditions

  • The prevalence of isolated STT joint OA is estimated to be 11–16%.1,2
  • Wrist OA is very rare in younger patients and is usually related to trauma.

Differential Diagnosis

  • OA of thumb CMC joint
  • De Quervain’s tenosynovitis
  • Flexor carpi radialis (FCR) tendinitis
  • Infection
  • Rheumatologic conditions
  • Scapholunate (SL) joint instability
ICD-10 Codes

  • OSTEOARTHRITIS, SCAPHOTRAPEZIAL TRAPEZOID

    Diagnostic Guide Name

    OSTEOARTHRITIS, SCAPHOTRAPEZIAL TRAPEZOID

    ICD 10 Diagnosis, Single Code, Left Code, Right Code and Bilateral Code

    DIAGNOSISSINGLE CODE ONLYLEFTRIGHTBILATERAL (If Available)
    OSTEOARTHRITIS, SCAPHOTRAPEZIAL TRAPEZOID M19.032M19.031 

    ICD-10 Reference

    Reproduced from the International statistical classification of diseases and related health problems, 10th revision, Fifth edition, 2016. Geneva, World Health Organization, 2016 https://apps.who.int/iris/handle/10665/246208

Clinical Presentation Photos and Related Diagrams
STT Osteoarthritis
  • Patients with STT arthritis will have tenderness in the anatomic snuff box without a history of wrist trauma.
    Patients with STT arthritis will have tenderness in the anatomic snuff box without a history of wrist trauma.
Symptoms
Pain is often present and can increase in intensity; however, STT osteoarthritis may be asymptomatic or mildly symptomatic.
Weakness of pinch and grip varies among patients.
Typical History

The typical patient is a woman ≥50 years old. There are case reports of STT OA in heavy-equipment operators and workers using screwdrivers and vibration tools. Piano playing may be a contributing factor.  Patients frequently complain of pain with pinch and grip.

Positive Tests, Exams or Signs
Work-up Options
Images (X-Ray, MRI, etc.)
STT Osteoarthritis Imaging
  • STT Osteoarthritis left wrist (arrow)
    STT Osteoarthritis left wrist (arrow)
  • STT Osteoarthritis left wrist after excision of the distal pole of the scaphoid. (arrow)
    STT Osteoarthritis left wrist after excision of the distal pole of the scaphoid. (arrow)
  • STT Osteoarthritis right wrist(1) with Thumb CMC Osteoarthritis (2). This will require different treatment than isolated STT Osteoarthritis.
    STT Osteoarthritis right wrist(1) with Thumb CMC Osteoarthritis (2). This will require different treatment than isolated STT Osteoarthritis.
Treatment Options
Treatment Goals
  • Control STT OA pain
  • Maintain wrist and hand function
Conservative
  • Intra-articular steroid injections
  • Oral anti-inflammatory drugs
  • Rest
  • Thumb spica splint 
Operative
  • Arthrodesis (fusion) of STT joint with or without radial styloidectomy
  • Arthroscopic debridement, possibly with interposition of a silicone spacer
  • Resection of distal pole of scaphoid (with or without biological tissue interposition), possibly with scaphoid trapezium pyrocarbon implant (STPI)
  • Trapeziectomy with partial proximal trapezoid excision
  • Postoperative immobilization and therapy 
Treatment Photos and Diagrams
STT Osteoarthritis Treatment
  • Distal scaphoid pole excision (arrow) for STT OA treatment
    Distal scaphoid pole excision (arrow) for STT OA treatment
  • Harvesting half of the ECRL tendon for a fascial arthroplasty after distal scaphoid excision.
    Harvesting half of the ECRL tendon for a fascial arthroplasty after distal scaphoid excision.
  • Combined STT & Thumb CMC OA (insert). This can not reliably be treated by trapeziectomy alone (1) because of residual ST OA (2).
    Combined STT & Thumb CMC OA (insert). This can not reliably be treated by trapeziectomy alone (1) because of residual ST OA (2).
  • Combined STT & Thumb CMC OA (insert). This can reliably be treated by trapeziectomy with ligament reconstruction and fascial arthroplasty(1) with excision of the proximal half of the trapezoid (2).
    Combined STT & Thumb CMC OA (insert). This can reliably be treated by trapeziectomy with ligament reconstruction and fascial arthroplasty(1) with excision of the proximal half of the trapezoid (2).
Complications

SURGICAL COMPLICATIONS 

  • Arthrodesis: high rate of nonunion; may result in loss of thumb mobility. STT fusion can impinge on the radial styloid.
  • Excisional arthroplasty: could worsen instability and cause DISI deformity in patients with dorsal midcarpal instability
  • Resection of distal pole of scaphoid: malalignment, requiring intercarpal arthrodesis
  • General: impingement, mechanical stress with consequent arthritic changes, motion limitations, non-union, numbness, painful neuroma, persistent soreness, secondary instability, thumb instability, weakness 
Outcomes
  • Arthrodesis: used for >30 years; offers good pain relief and preservation of motion and strength, but long-term results mixed 
  • Resection of distal pole of scaphoid:  good pain relief achieved without compromising function 
Video
Fascial arthroplasty and distal scaphoid excision for STT Osteoarthritis treatment
YouTube Video
Scaphotrapezial Trapezoid (STT) Osteoarthritis
Key Educational Points
  • Patients can be tender over the STT joint without radiographic evidence of OA.
  • Conversely, pain can be absent in the presence of STT OA. This may be due to:
    • An immobile STT joint
    • An unstable STT joint, but with support of a sliding scaphoid beneath the trapezium and trapezoid; load is preferentially transferred through the capitate and lunate
    • Lack of pain receptors in STT joint ligaments
  • The STT joint is the second most common site of radiographic OA in the wrist, reported in 15–29% of wrist radiographs; a much higher rate (≤83%) has been reported in cadaver studies.
  • Patients with familial articular hypermobility are especially susceptible to STT joint OA.
  • The ideal surgical treatment has not been determined.
References

New Article

  1. Marcuzzi A, Ozben H, Russomando A. Treatment of scaphotrapezial trapezoidal osteoarthritis with resection of the distal pole of the scaphoid. Acta Orthop Traumatol Turc 2014;48(4):431-6. PMID: 25230267
  2. Kapoutsis DV, Dardas A, Day CS. Carpometacarpal and scaphotrapeziotrapezoid arthritis: arthroscopy, arthroplasty, and arthrodesis. J Hand Surg Am 2011;36(2):354-66. PMID: 21276902

Review

  1. Kapoutsis DV, Dardas A, Day CS. Carpometacarpal and scaphotrapeziotrapezoid arthritis: arthroscopy, arthroplasty, and arthrodesis. J Hand Surg Am 2011;36(2):354-66. PMID: 21276902

Classic

  1. Irwin LR, Outhwaite J, Burge PD. Rupture of the flexor carpi radialis tendon associated with scapho-trapezial osteoarthritis. J Hand Surg Br 1992;17(3):343-5. PMID: 1624871
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