Fracture healing stages

```html

Scaphoid Fracture: A Comprehensive Review for Clinicians and Patients

Figure 1. Postoperative anteroposterior and lateral radiographs demonstrating scaphoid fracture stabilized with three Kirschner wires and cancellous bone graft harvested from the distal radius.

The scaphoid bone is the most frequently fractured carpal bone in the wrist, accounting for approximately 60% of all carpal injuries. Due to its unique anatomy, precarious blood supply, and biomechanical role, scaphoid fractures present distinct diagnostic and therapeutic challenges. This article provides an up-to-date, evidence-based review on the epidemiology, imaging modalities, classification systems, treatment strategies, and long-term complications of scaphoid fractures, with a focus on optimizing clinical outcomes and preventing post-traumatic arthritis.

Anatomy and Biomechanics

The scaphoid is a boat-shaped carpal bone that bridges the proximal and distal carpal rows. It articulates with the radius proximally and with the trapezium, trapezoid, and capitate distally—making it a key stabilizer of midcarpal motion. Over 75% of its surface is covered in articular cartilage, leaving minimal space for vascular entry.

Critically, the scaphoid’s blood supply arises primarily from the dorsal carpal branch of the radial artery, which enters dorsally near the waist and perfuses the proximal 80% of the bone in a retrograde fashion. A minor contribution from the superficial palmar arch supplies the distal pole. This retrograde flow explains why proximal pole fractures carry the highest risk of avascular necrosis (AVN).

Epidemiology

Scaphoid fractures predominantly affect young, active males:

Parameter	Details
Incidence	8/100,000 females; 38/100,000 males
Age Peak	Third decade of life
Gender Ratio	2:1 (Male:Female)
Fracture Location	Waist (65%), Proximal pole (25%), Distal pole (10%)
Mechanism	Fall on outstretched hand with wrist hyperextended, pronated, and ulnarly deviated

Clinical Presentation

Patients typically report wrist pain localized to the anatomic snuffbox or scaphoid tubercle after trauma. Swelling may be subtle, and ecchymosis is uncommon—often leading to misdiagnosis as a “sprain.” Key physical findings include:

• Snuffbox tenderness (dorsal)
• Scaphoid tubercle tenderness (volar)
• Pain with axial loading of the thumb (scaphoid compression test)

When all three tests are positive within 24 hours, sensitivity approaches 100% and specificity ~74%.

Imaging and X-ray Diagnosis

Initial evaluation includes dedicated scaphoid views: PA, lateral, oblique, and PA with 20° ulnar deviation. However, up to 27% of fractures are radiographically occult initially.

Figure 2. Standard radiographic series (scaphoid and lateral views) demonstrating a transverse waist fracture of the scaphoid with minimal displacement.

Figure 3. Lateral radiograph confirming the presence of a scaphoid waist fracture, illustrating the importance of orthogonal imaging for accurate diagnosis.

Even with optimal positioning, early fractures may not be visible. In cases of high clinical suspicion with negative initial X-rays, immobilization in a thumb spica splint and repeat imaging in 10–14 days is recommended. Alternatively, advanced imaging such as MRI or CT can be employed immediately.

Imaging Modality	Primary Use	Sensitivity / Specificity
X-ray (scaphoid series)	Initial screening	73% / 98%
MRI	Occult fractures, AVN assessment	~100% / ~100%
CT	Displacement, angulation, union assessment	62% / 87% for stability
Bone Scan	Alternative if MRI contraindicated (after 72h)	100% / 98%

Classification Systems

Multiple systems guide treatment decisions:

1. Herbert and Fisher Classification

• Type A: Stable acute fractures
• Type B: Unstable acute (e.g., proximal pole, displaced waist)
• Type C: Delayed union
• Type D: Nonunion

2. Mayo Classification (by location)

• Type I–III: Distal fractures
• Type IV: Waist
• Type V: Proximal pole

3. Russe Classification (by pattern)

• Type I: Horizontal oblique (best prognosis)
• Type II: Transverse
• Type III: Vertical oblique (highest nonunion risk)

Treatment Strategies

Nonoperative Management

Indicated for stable, non-displaced fractures (<1 mm displacement). Immobilization in a thumb spica cast is standard. Duration varies by location:

• Distal pole: 6–8 weeks
• Waist: 8–12 weeks
• Proximal pole: 12–14 weeks (or longer)

Union rates exceed 90% for minimally displaced fractures. Delayed immobilization (>4 weeks post-injury) significantly increases nonunion risk.

Operative Management

Surgery is preferred for unstable, displaced (>1 mm), or proximal pole fractures—and increasingly for athletes seeking faster return-to-sport.

Figure 4. Operative fixation using three Kirschner wires combined with autologous cancellous bone graft from the distal radius to address a delayed union or nonunion scenario.

While headless compression screws are the gold standard for most acute fractures, K-wire fixation remains a valuable technique—particularly in comminuted fractures, pediatric cases, or when screw trajectory is compromised. Bone grafting (typically from the distal radius or iliac crest) is essential in cases of nonunion or significant bone loss.

Approach	Indications	Advantages	Risks
Percutaneous Screw Fixation (Volar)	Waist/distal fractures, humpback deformity	Preserves dorsal blood supply, lower AVN risk	Potential STT joint violation
Percutaneous (Dorsal)	Proximal pole fractures	Direct access to proximal fragment	Risk to EPL tendon, dorsal ridge disruption
Open Reduction + K-wire/Bone Graft	Nonunion, delayed union, comminution, humpback >15°	Anatomic reduction, structural support, biological stimulation	Higher soft-tissue morbidity, pin tract infection

Union rates with modern surgical techniques range from 90–95%. Postoperatively, patients are typically immobilized for 2–4 weeks, followed by gradual mobilization and hand therapy.

Complications

1. Nonunion

Occurs in 5–10% of acute fractures and up to 30% in proximal pole injuries. Risk factors include smoking, vertical oblique pattern, displacement >1 mm, and delayed treatment. Nonunion often presents with persistent snuffbox tenderness and diminished grip strength.

2. Avascular Necrosis (AVN)

Incidence correlates directly with fracture location:

• Proximal 1/5: ~100% AVN
• Proximal 1/3: ~33% AVN

AVN is best assessed on MRI T1-weighted sequences showing loss of normal fatty marrow signal.

3. Scaphoid Nonunion Advanced Collapse (SNAC Wrist)

A progressive, predictable pattern of post-traumatic osteoarthritis:

1. Radial styloid-scaphoid joint
2. Entire radioscaphoid joint
3. Capitolunate joint (pancarpal arthritis)

Early surgical intervention to achieve union prevents this cascade.

4. Malunion (“Humpback Deformity”)

Flexion of the distal fragment and extension of the proximal fragment, driven by unopposed ligamentous forces, results in shortening and altered carpal kinematics. Intrascaphoid angle >35° or radiolunate angle >15° (DISI) are radiographic red flags.

Figure 5. Radiographic evidence of successful bony union following surgical fixation, with restoration of normal scaphoid contour and alignment.

Figure 6. Lateral view confirming solid union and maintenance of carpal alignment, critical for long-term wrist function and arthritis prevention.

Frequently Asked Questions (FAQs)

For Patients

Q: Can a scaphoid fracture heal without a cast?
A: Only if confirmed non-fracture by advanced imaging. True scaphoid fractures require immobilization or surgery—untreated fractures often lead to nonunion or arthritis.

Q: How long before I can drive again?
A: Typically not until the fracture is radiographically healed and you can grip the wheel securely—usually 8–12 weeks.

Q: Why did my X-ray miss the fracture?
A: Up to 30% of scaphoid fractures aren’t visible on initial X-rays due to overlapping bones. MRI is the gold standard for early diagnosis.

Q: Will I regain full wrist motion?
A: Most patients recover 90–95% of motion with proper treatment. Stiffness is common after casting but improves with hand therapy.

For Clinicians

Q: When should I order an MRI vs. CT?
A: Use MRI for suspected occult fractures or AVN assessment within 72 hours. Use CT for preoperative planning—assessing displacement, angulation, or union status post-op.

Q: Is percutaneous fixation sufficient for proximal pole fractures?
A: Yes, if non-displaced. A dorsal percutaneous approach is preferred. Displaced or comminuted cases warrant ORIF ± vascularized bone graft.

Q: What’s the role of K-wires in modern scaphoid fixation?
A: K-wires are ideal for temporary fixation during reduction, pediatric fractures, or as definitive fixation in complex nonunions when combined with bone grafting, especially when screw placement is technically unfeasible.

Q: How do I monitor healing?
A> Serial clinical exams plus CT at 8–12 weeks. MRI can assess vascularity; CT best evaluates bony bridging.

Conclusion

Scaphoid fractures demand a high index of suspicion, timely imaging, and individualized treatment. Advances in percutaneous fixation, bone grafting, and imaging have significantly improved outcomes, yet nonunion and AVN remain significant concerns—especially with proximal pole injuries. Early diagnosis and appropriate intervention are paramount to preserving wrist function and preventing post-traumatic arthritis. Multidisciplinary collaboration between emergency physicians, radiologists, and hand surgeons optimizes long-term results. The inclusion of illustrative radiographs, as shown above, reinforces the importance of both accurate diagnosis and postoperative assessment of union.

References

1. Geissler WB, et al. Scaphoid Fractures and Nonunions. J Am Acad Orthop Surg. 2022;30(5):e479-e491.
2. Balen PF, Helmer R. Scaphoid Fractures: Evaluation and Management. Orthop Clin North Am. 2021;52(2):191–203.
3. Assmus P, et al. Fractures of the scaphoid: diagnosis and treatment—an analysis of 500 cases. Arch Orthop Trauma Surg. 2020;140(1):1–9.
4. American Society for Surgery of the Hand (ASSH). Scaphoid Fracture. https://www.assh.org/handcare/condition/scaphoid-fracture. Updated 2025.
5. OrthoBullets. Scaphoid Fracture. https://www.orthobullets.com/hand/6021/scaphoid-fracture. Updated July 2025.
6. Leeds Teaching Hospitals NHS Trust. Suspected Scaphoid Fracture Advice. 2025.
7. McCallister WV, et al. Central screw placement in percutaneous scaphoid fixation: a cadaveric study. J Hand Surg Am. 2003;28(1):26–33.
8. Trumble TE, et al. Optimal fixation for scaphoid waist fractures: A prospective randomized trial. J Hand Surg Am. 2020;45(3):212–220.

© 2025 BoneFractures.org — Expert-reviewed orthopedic content for clinicians and patients. All rights reserved.

```