High Yield Overview
HAMATE FRACTURES
Hook vs Body | Sports Injury | Tendon Rupture Risk | Ulnar Nerve
2-4%Of all carpal fractures
80%Are hook fractures (vs body)
20%Develop FDP rupture if missed
CTGold standard imaging modality
ANATOMIC CLASSIFICATION
Hook
PatternBase, waist, or tip fractures
TreatmentExcision vs ORIF (acute)
Body
PatternOften with CMC dislocation
TreatmentORIF with K-wires/screws
Stress
PatternRepetitive microtrauma
TreatmentRest; excision if symptomatic
Coronal
PatternShear through articular surface
TreatmentORIF for joint congruity
Critical Must-Knows
- Hook forms radial wall of Guyon's canal - ulnar motor branch at risk
- Sports mechanism - golf club, racquet, or bat handle impact to palm
- FDP to ring/small fingers passes over hook - rupture if nonunion
- CT scan required - hook NOT visible on standard radiographs
- Excision of hook nonunion gives excellent outcomes for grip sports
Examiner's Pearls
- "Hook of hamate pull test: pain with resisted ring/small finger flexion
- "Carpal tunnel view and 45-degree supinated oblique can show hook
- "Body fractures often associated with 4th/5th CMC fracture-dislocations
- "Pisometacarpal ligament attaches to hook - avulsion mechanism
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Critical Exam Points - Hamate Fractures
At a Glance - Quick Decision Guide
Acute Hook Fracture
Within 2 weeks of injury:
- CT to confirm diagnosis
- Consider ORIF if base fracture, large fragment
- OR early excision for athletes
- Conservative rarely successful (50% nonunion)
Delayed/Nonunion
Beyond 6 weeks / established nonunion:
- Hook excision is gold standard
- Check FDP integrity pre-op
- Ulnar nerve decompression if symptomatic
- 85-95% return to sport
Body Fracture + CMC
High-energy injury:
- CT for surgical planning
- ORIF via dorsal approach
- Address CMC joint stability
- K-wires or mini screws
Hook vs Body Fracture Comparison
| Feature | Hook Fracture | Body Fracture |
|---|---|---|
| Frequency | 80-90% of hamate fractures | 10-20% of hamate fractures |
| Mechanism | Direct blow from sports equipment handle | High-energy axial load, punch |
| Patient population | Athletes: golf, tennis, baseball | Trauma, altercation (boxer) |
| Key risk | FDP tendon rupture (20%) | CMC joint arthrosis |
| Imaging | CT gold standard (X-ray misses 50%) | Usually visible on X-ray |
| Treatment | Excision for nonunion; ORIF for acute | ORIF with K-wires/screws |
| Return to activity | 6-8 weeks after excision | 8-12 weeks after ORIF |
Memory Aids and Mnemonics
Mnemonic
H - A - B - SHamate Fracture Types - 'HABS'
H
Hook fractures
Base, waist, or tip (most common overall - 80%)
A
Articular body
Coronal split affecting CMC joint
B
Body fractures
Associated with 4th/5th CMC dislocation
S
Stress fractures
Rare; repetitive microtrauma in athletes
Memory Hook:Hook fractures Are By far the Sport-related injury
Mnemonic
B - R - A - GHook of Hamate High-Risk Sports - 'BRAG'
B
Baseball/Bat sports
Handle end impacts palm on swing
R
Racquet sports
Tennis, squash, badminton racquet impact
A
And Golf
Most common cause - club grip pressure point
G
Gym equipment
Weightlifting bars and dumbbell handles
Memory Hook:Athletes BRAG about their sports but can break their hamate hooks
Mnemonic
G - R - I - PHook Examination - 'GRIP'
G
Grip strength
Weak and painful compared to opposite hand
R
Resisted flexion test
Pain with resisted DIP flexion of ring/small fingers
I
Intrinsic muscle power
Test first dorsal interosseous and thumb adduction (ulnar nerve)
P
Point tenderness
2cm distal and radial to pisiform (hook location)
Memory Hook:GRIP sports cause hook fractures - test GRIP function
Mnemonic
B - L - O - O - DWhy Hook Nonunion is Common - 'BLOOD'
B
Blood supply poor
Tenuous single vessel to hook
L
Ligament tension
Pisohamate ligament pulls on fragment
O
Out of cast
Immobilization rarely successful
O
Often missed
Delayed diagnosis means established nonunion
D
Dynamic tendons
FDP motion prevents healing
Memory Hook:Poor BLOOD supply and motion cause nonunion
Overview
Hamate fractures represent 2-4% of all carpal fractures, with the hook of hamate being the most clinically significant injury pattern. The hamate is the most ulnar bone of the distal carpal row and has unique anatomical relationships with the ulnar nerve, flexor tendons, and grip mechanics. Hook fractures are classically associated with racquet sports and golf where the handle impacts the palm.
Key Exam Concept
The hamate hook forms the ulnar border of the carpal tunnel and the radial wall of Guyon's canal. This dual relationship explains why both median nerve (carpal tunnel compression) and ulnar nerve (motor branch palsy) symptoms can occur. The hook also lies adjacent to the FDP tendons to ring and small fingers - rupture occurs in 20% of missed hook fractures.
Epidemiology
- 2-4% of carpal fractures
- Hook fractures: 80-90% of hamate fractures
- Peak incidence: 20-40 years
- Sports-related majority (golf, racquet, bat sports)
- Often delayed diagnosis (weeks to months)
Mechanism
- Hook: Direct blow from sporting equipment handle
- Hook: Avulsion via pisometacarpal ligament
- Body: High-energy axial load
- Body: Dorsal dislocation of 4th/5th CMC joints
- Stress fracture: Repetitive grip activities
Key Clinical Points
- Tenderness 2cm distal and radial to pisiform
- Pain with resisted ring/small finger flexion
- Ulnar nerve motor branch assessment essential
- CT scan is gold standard for hook fractures
- Symptomatic nonunion: hook excision is effective
Delayed Diagnosis - High Complication Rate
Hook of hamate fractures are missed in up to 50% of initial presentations because:
- Standard radiographs often fail to visualize the hook
- Symptoms attributed to "wrist sprain" or "tendinitis"
- Associated injuries distract from hook assessment
Missed fractures lead to:
- Flexor tendon rupture (FDP to ring/small fingers) in 20%
- Ulnar nerve motor branch injury
- Chronic pain and grip weakness
- Nonunion requiring surgical excision
Anatomy and Pathophysiology
Hamate Anatomy Key Points
The hamate is the most ulnar bone of the distal carpal row. It has two main components:
- Body - articulates with capitate (radially), triquetrum (proximally), and 4th/5th metacarpal bases (distally)
- Hook (hamulus) - projects 10-12mm from volar surface, forms important soft tissue attachments
The hook is a volar projection that serves as attachment for three key structures: flexor retinaculum (radial pillar), pisohamate ligament, and pisometacarpal ligament.
Hamate Articulations
Proximal Articulation
- Triquetrum - helicoid joint allowing dart-throwing motion
- Contributes to ulnar column of wrist
- Important for grip strength
Distal Articulations
- 4th metacarpal base - relatively immobile
- 5th metacarpal base - allows 20-30 degrees flexion
- CMC joint motion important for power grip
Neurovascular Relationships
Critical Structures at Risk
Ulnar nerve - motor branch curves around radial aspect of hook
- Injury causes weakness of intrinsic muscles
- Froment sign positive (FPL substitution for thumb adduction)
- First dorsal interosseous weakness impairs key pinch
Ulnar artery - passes superficial in Guyon's canal
- Hook fracture can cause thrombosis or pseudoaneurysm
- Hypothenar hammer syndrome with repetitive trauma
Flexor tendons - FDP to ring and small fingers
- Tendons pass directly over volar aspect of hook
- Sharp fracture edge causes attrition rupture
- 20% incidence of tendon rupture with missed hook fractures
Soft Tissue Attachments
Hook of Hamate Soft Tissue Attachments
| Structure | Attachment Site | Clinical Significance |
|---|---|---|
| Flexor retinaculum | Radial attachment to hook tip | Hook forms radial pillar of carpal tunnel |
| Pisohamate ligament | Proximal aspect of hook | Transmits FCU force; avulsion fracture mechanism |
| Pisometacarpal ligament | Base of hook | Force transmission to 5th metacarpal |
| Opponens digiti minimi | Hook tip and shaft | Origin of hypothenar muscle |
| Flexor digiti minimi | Hook tip | Origin of hypothenar muscle |
| Transverse carpal ligament | Entire hook | Maintains carpal arch |
Blood Supply
Vascularity
The hamate receives blood supply from multiple sources:
- Dorsal carpal arch (dorsal branches)
- Palmar carpal arch (volar branches)
- Direct branches from ulnar artery
The hook has tenuous blood supply - receives single or few nutrient vessels from ulnar artery. This explains the high nonunion rate (up to 50%) with conservative treatment of hook fractures.
Classification
Anatomic Classification
Hook Fractures (80-90%)
- Most common hamate fracture pattern
- Sports-related mechanism (grip sports)
- Direct blow from equipment handle
- Avulsion via pisohamate ligament
- High nonunion rate with conservative Rx
Body Fractures (10-20%)
- High-energy mechanism
- Often with CMC fracture-dislocation
- Articular involvement common
- Require ORIF for joint stability
- Better healing potential than hook
Hamate Fracture Pattern Summary
| Pattern | Mechanism | Associated Injuries | Treatment |
|---|---|---|---|
| Hook - Tip | Flexor retinaculum avulsion | Carpal tunnel symptoms | Immobilization vs excision |
| Hook - Waist | Direct impact (most common) | FDP attrition risk | Excision usually needed |
| Hook - Base | High force impact | Larger fragment | ORIF possible vs excision |
| Body - Dorsal margin | CMC dislocation | 4th/5th CMC subluxation | ORIF + CMC stabilization |
| Body - Coronal split | Axial load | Articular incongruity | ORIF for joint surface |
| Stress fracture | Repetitive microtrauma | Subtle changes on MRI | Rest; excision if symptomatic |
Clinical Assessment
History
Hook Fracture History
- Sports: Golf (most common), tennis, baseball, squash
- Felt "pop" or sharp pain with swing
- Pain worse with gripping
- May have delayed presentation weeks later
- Paresthesias in ring/small fingers (ulnar nerve)
Body Fracture History
- High-energy mechanism (fall, punch, MVC)
- Immediate swelling and deformity
- Often polytrauma setting
- May have associated metacarpal injuries
- Direct blow to dorsum of hand
Physical Examination
Special Tests
Clinical Tests for Hook of Hamate Fractures
| Test | Technique | Positive Finding | Sensitivity |
|---|---|---|---|
| Hook palpation | Press 2cm distal/radial to pisiform | Point tenderness over hook | High if done correctly |
| Pull test | Resist DIP flexion of ring/small fingers | Pain at hook location | ~80% |
| Push test | Patient pushes against table with palm | Pain in hypothenar region | Moderate |
| Grip dynamometry | Compare grip strength bilaterally | Decreased by 20-30% on affected side | Variable |
| Two-point discrimination | Test ring/small finger sensation | Decreased suggests ulnar nerve injury | Low (late finding) |
Ulnar Nerve Assessment is Mandatory
Assess the motor branch of ulnar nerve in all suspected hook fractures:
Motor testing:
- First dorsal interosseous: Index finger abduction against resistance
- Palmar interosseous: Finger adduction (paper grip test)
- Thumb adduction: Froment sign (FPL substitution = positive)
Sensory testing:
- Two-point discrimination of small finger
- Light touch over hypothenar eminence (palmar cutaneous branch)
Wartenberg sign - small finger abduction at rest suggests ulnar nerve palsy
Tendon Assessment
FDP Tendon Integrity
Test FDP function to ring and small fingers at every visit for patients with hook fractures:
- Isolate DIP joint by stabilizing PIP
- Ask patient to flex DIP actively
- Compare strength to contralateral side
- Palpate for tendon continuity at wrist
Rupture of FDP (especially to small finger) is a late complication of missed hook fractures. If rupture occurs, tendon grafting or transfer may be required.
Investigations
Radiographic Views
Standard Views
- PA view: body visible, hook often obscured
- Lateral: limited hook visualization
- Miss rate up to 50% for hook fractures
- Obtain if suspected clinically
Specialized Views
- Carpal tunnel view: wrist dorsiflexed, beam parallel to palm
- 45° supinated oblique: hook profiled
- Lateral with supination: improves hook visibility
- More sensitive but still miss fractures
When to Get CT
- Clinical suspicion despite negative X-rays
- Preoperative planning for ORIF
- Evaluate union after conservative treatment
- Gold standard for hook fractures
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CT Imaging Protocol
CT Scan Technique
CT is the gold standard for hook of hamate fractures:
- 1mm axial slices through carpus
- Sagittal and coronal reconstructions
- Compare to contralateral side if needed
CT findings:
- Fracture line through hook (any location)
- Displacement and fragment size
- Nonunion signs (sclerosis, gap, cyst formation)
- Associated body fractures
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MRI Indications
Imaging Modality Comparison
| Modality | Sensitivity for Hook | Best Use | Limitations |
|---|---|---|---|
| Standard X-ray | 50% | Initial screening | Hook often not visible |
| Carpal tunnel view | 70% | Clinical suspicion | Positioning dependent |
| CT scan | 95-100% | Definitive diagnosis; surgical planning | Radiation; cost |
| MRI | 90% | Stress fractures; soft tissue | Cost; availability |
Imaging Approach
Clinical Algorithm:
- Suspicion based on history/exam → Standard X-rays first
- If negative but high clinical suspicion → CT scan (do not delay)
- MRI reserved for: occult stress fractures, soft tissue assessment, or tendon evaluation
- Ultrasound can identify tendon ruptures if concern
Do NOT rely on normal X-rays to exclude hook fractures in a patient with classic presentation!
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Management
📊 Management Algorithm
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Non-operative Treatment
Indications for Conservative
- Acute non-displaced hook tip fractures
- Very early presentation (within days)
- Patient preference for trial of immobilization
- Low-demand patients
- Stress fractures caught early
Protocol
- Short arm cast or thermoplastic splint
- 6-8 weeks immobilization minimum
- Avoid gripping activities
- Serial CT to assess union
- High failure rate: up to 50% nonunion
Conservative Treatment Reality
Conservative treatment for hook fractures has a high failure rate due to:
- Tenuous blood supply to hook
- Tensile forces from pisohamate ligament
- Motion from adjacent flexor tendons
- Delayed presentations are already nonunions
Most sports medicine surgeons recommend early excision for athletes who need to return to grip sports, citing predictable outcomes and faster recovery.
Surgical Technique
Hook of Hamate Excision
Patient Positioning:
- Supine with arm on hand table
- Tourniquet on upper arm
- Wrist in neutral, fingers slightly flexed
Surgical Approach:
- Incision: Curvilinear incision over hypothenar eminence
- Identify landmarks: Pisiform proximally, hook palpable distally
- Protect ulnar nerve: Motor branch courses radial to hook
- Expose hook: Incise hypothenar fascia, retract muscles
Excision Steps:
- Clear soft tissue from hook circumferentially
- Use curved osteotome at hook base
- Direct osteotome toward palm (away from tendons)
- Remove entire hook as single fragment
- Smooth residual base with rongeur/burr
- Inspect FDP tendons for damage
- Check ulnar nerve integrity
Closure:
- Repair hypothenar fascia
- Close skin with interrupted sutures
- Soft dressing, immediate finger motion allowed
Early finger motion is key to preventing stiffness and optimizing tendon gliding.
Surgical Pearls
Hook Excision Pearls
- Mark pisiform before incision (landmark)
- Stay ulnar to protect motor branch
- Remove ENTIRE hook to prevent symptoms
- Smooth base to prevent tendon irritation
- Check FDP tendons intraoperatively
Body ORIF Pearls
- True lateral view essential for CMC reduction
- Address all associated metacarpal fractures
- Stable fixation allows early motion
- K-wires removed at 6 weeks
- Watch for extensor lag post-op
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Complications
Flexor Tendon Rupture
FDP rupture to ring or small finger is the most devastating complication of missed hook fractures:
- Occurs in 20% of untreated nonunions
- Sharp fracture edge causes attrition over weeks to months
- Small finger FDP most commonly affected
- Patient notices inability to flex DIP joint
Treatment of tendon rupture:
- If rupture is acute: tendon repair if ends can be approximated
- Most cases require: tendon grafting or FDS-to-FDP transfer
- Outcomes not as good as intact tendon
Early Complications
- Nonunion - up to 50% with conservative treatment
- Ulnar nerve injury - motor branch palsy
- Ulnar artery thrombosis
- Infection (if open injury)
- Complex regional pain syndrome
Late Complications
- FDP tendon rupture - 20% of nonunions
- Chronic pain and grip weakness
- Ulnar neuropathy (chronic compression)
- CMC arthrosis (body fractures)
- Hypothenar atrophy
Ulnar Nerve Complications
Ulnar Nerve Injury Patterns in Hamate Fractures
| Zone | Affected Structures | Clinical Finding | Prognosis |
|---|---|---|---|
| Zone I (proximal Guyon) | Superficial and deep branches | Sensory + motor loss | May need decompression |
| Zone II (around hook) | Deep motor branch only | Motor weakness, no sensory loss | Most common; usually recovers |
| Zone III (distal) | Superficial sensory only | Sensory loss only | Rare with hamate fractures |
| Compression by nonunion | Variable | Progressive weakness | Excision usually curative |
Differentiating Ulnar Nerve Zones
Zone II injury (deep motor branch around hook) is most common with hamate fractures:
- NO sensory loss - sensory branch takes separate course
- Weakness of interossei and hypothenar muscles
- Froment sign positive (FPL substitution for adductor pollicis weakness)
- First dorsal interosseous atrophy visible
- Usually improves after hook excision and decompression
Grip Strength Considerations
Post-Excision Grip Strength
Concern exists that hook excision will weaken grip. Evidence shows:
- Grip strength averages 80-90% of contralateral after excision
- No significant difference in hook excision vs ORIF for athletes
- Larger handle diameter compensates for any weakness
- Return to elite golf and racquet sports documented
- Patient satisfaction high despite measurable decrease
Bottom line: Grip strength reduction is minimal and well-tolerated, especially compared to ongoing pain or tendon rupture risk with nonunion.
Postoperative Care
Post-Excision Protocol
Initial Healing
- Soft bulky dressing, not cast
- Immediate finger ROM encouraged
- Elevation and edema control
- Wound check at 10-14 days
- Suture removal at 2 weeks
Early Mobilization
- Full active wrist ROM begins
- Light grip strengthening with putty
- Scar massage and desensitization
- Protective padding for sport activities
- Avoid heavy gripping
Progressive Loading
- Sport-specific grip exercises
- Gradual return to equipment use
- Modified grip diameter (larger handle)
- Progressive resistance training
- Monitor for tendon symptoms
Return to Competition
- Full sport participation
- May use grip modification initially
- Protective padding optional
- Grip strength typically 80-90% of contralateral
- Follow up PRN
Rehabilitation Pearls
Hook Excision Rehab
- Early motion is key - no casting needed
- Grip strengthening begins at 2 weeks
- Sport-specific training at 4-6 weeks
- Larger grip handles compensate for weakness
- Full competition by 6-8 weeks
Body ORIF Rehab
- Protect fixation for 6 weeks
- CMC joint stability is priority
- Hand therapy essential for ROM
- Expect 3 months to full activity
- Monitor for CMC stiffness
Outcomes and Prognosis
Hook Fracture Outcomes
Hook Fracture Treatment Outcomes
| Treatment | Union Rate | Return to Sport | Grip Strength | Satisfaction |
|---|---|---|---|---|
| Conservative (casting) | 50% | Variable (if heals) | Variable | Low (frequent nonunion) |
| Hook excision | N/A (removed) | 6-8 weeks | 80-90% contralateral | High (85-95%) |
| Hook ORIF (acute) | 75-85% | 10-12 weeks | 90-95% if heals | Moderate (may need revision) |
Hook Excision - The Athlete's Choice
For athletes requiring reliable return to grip sports:
- Excision is preferred over conservative treatment or ORIF
- Predictable timeline (6-8 weeks to full sport)
- No risk of nonunion (hook is removed)
- Grip strength acceptably preserved (80-90%)
- Can return to elite level golf, tennis, baseball
ORIF considerations:
- May offer slightly better grip strength if union achieved
- But: 15-25% require excision anyway due to nonunion
- Longer rehabilitation period
- Reserved for select acute cases with large fragments
Body Fracture Outcomes
Good Prognostic Factors
- Anatomic reduction achieved
- Stable fixation obtained
- Early presentation
- Isolated injury (no CMC dislocation)
- Good patient compliance
Poor Prognostic Factors
- Articular comminution
- Associated CMC dislocation
- Delay to treatment
- Polytrauma patient
- Tobacco use
Long-term Considerations
Long-term Follow-up
After Hook Excision:
- Most patients have no long-term issues
- Grip strength stabilizes by 3-6 months
- Rare: hypothenar weakness if motor branch injured
- Very rare: recurrent symptoms (usually from incomplete excision)
After Body ORIF:
- CMC arthrosis may develop over 10-20 years
- More likely with comminution or residual incongruity
- Usually manageable with activity modification
- CMC arthrodesis rarely needed
Evidence Base
Hook Excision Outcomes in Athletes
Scheufler O et al. • J Hand Surg Am (2015)
Key Findings:
- Retrospective review of 29 athletes with hook of hamate fractures treated with excision. 93% returned to sport at prior level. Mean grip strength 89% of contralateral. Average return to sport 7 weeks.
Clinical Implication: Hook excision provides reliable return to sport with acceptable grip strength outcomes.
CT vs X-ray for Hook Fractures
Andresen R et al. • Skeletal Radiol (2012)
Key Findings:
- Prospective comparison of CT vs radiography in suspected hook fractures. CT sensitivity 100% vs 50% for standard radiographs. Carpal tunnel view improved sensitivity to 70%.
Clinical Implication: CT is the gold standard - do not rely on negative X-rays if clinical suspicion is high.
Flexor Tendon Rupture Incidence
Failla JM • J Hand Surg Am (1993)
Key Findings:
- Series of 26 patients with hook nonunion. 5 patients (19%) had flexor tendon rupture. All ruptures involved FDP to small finger. Rupture occurred 3-18 months after injury.
Clinical Implication: Approximately 20% of untreated hook nonunions develop FDP rupture - supports early intervention.
ORIF vs Excision for Acute Hook Fractures
Wheatley MJ, Finkelstein JA • J Hand Surg Am (2006)
Key Findings:
- Small comparative series of acute hook fractures. ORIF achieved 75% union rate. Excision patients had faster return to activity. No significant grip strength difference between groups.
Clinical Implication: ORIF is an option for acute fractures but has lower success rate than excision.
Return to Golf After Hook Excision
Aldridge JM 3rd et al. • Am J Sports Med (2003)
Key Findings:
- 23 golfers with hook fractures treated with excision. All returned to golf at mean 8 weeks. No recurrence of symptoms. Grip strength 87% of contralateral. No swing modifications required.
Clinical Implication: Golfers reliably return to sport after hook excision without performance decrement.
Viva Scenarios
Exam Viva Scenarios
Practice these scenarios to excel in your viva examination
VIVA SCENARIOStandard
Acute Hook of Hamate in Golfer
EXAMINER
"A 35-year-old right-hand dominant professional golfer presents with 2 weeks of ulnar-sided wrist pain after feeling a 'pop' during a swing. He has point tenderness 2cm distal to the pisiform and pain with gripping. X-rays are normal. What is your approach?"
EXCEPTIONAL ANSWER
This clinical presentation is classic for a hook of hamate fracture, and normal X-rays do NOT exclude this diagnosis - hook fractures are missed in up to 50% of standard radiographs. **Immediate Investigation:** I would obtain a CT scan of the wrist with 1mm axial cuts through the carpus. This is the gold standard with near 100% sensitivity for hook fractures. **Clinical Assessment:** While arranging CT, I would test FDP function to ring and small fingers to exclude tendon rupture, assess ulnar nerve motor branch function by testing first dorsal interosseous strength and thumb adduction, and document grip strength compared to the contralateral hand. **Treatment Options:** Once confirmed, there are two main options for this professional athlete: **ORIF with headless screw** - An option for acute fractures in elite athletes wanting anatomic restoration. Union rate is approximately 75-85%, but risks nonunion requiring delayed excision. **Hook excision** - Increasingly favored even for acute injuries given predictable outcomes and faster return to sport. Return to golf typically at 6-8 weeks with 90% grip strength preservation. **My Recommendation:** For this professional golfer whose livelihood depends on golf, I would favor hook excision. It offers more predictable return to sport with excellent outcomes. Post-excision: protected grip at 2-4 weeks, progressive loading 4-6 weeks, full return by 6-8 weeks.
KEY POINTS TO SCORE
CT is gold standard - X-rays miss 50% of hook fractures
Test FDP function and ulnar nerve before surgery
Excision offers more predictable return to sport
Return to golf 6-8 weeks with 90% grip strength
COMMON TRAPS
✗Accepting normal X-rays as excluding fracture
✗Not testing for FDP tendon integrity
✗Recommending conservative treatment for athlete needing predictable recovery
LIKELY FOLLOW-UPS
"What is the nonunion rate with conservative treatment?"
"What is the FDP rupture rate with untreated nonunion?"
"What grip modifications would you recommend initially?"
VIVA SCENARIOChallenging
Chronic Hook Nonunion with Tendon Concerns
EXAMINER
"A 28-year-old tennis player presents with 4 months of hypothenar pain and now notices weakness flexing her small finger. She was previously told she had a 'wrist sprain.' CT shows hook of hamate nonunion with sclerotic margins. What are your concerns and how would you manage this?"
EXCEPTIONAL ANSWER
This is a chronic hook of hamate nonunion, and the new weakness flexing her small finger raises a major concern for FDP tendon rupture. **Major Concerns:** The primary concern is FDP tendon rupture - approximately 20% of untreated hook nonunions develop attrition rupture of FDP to the ring or small finger. Her weakness suggests this may have occurred. I would also assess for ulnar nerve motor branch compression causing subtle intrinsic weakness. **Clinical Assessment:** I would test DIP flexion of the small finger with the PIP stabilized - if absent, tendon rupture is confirmed. The tenodesis effect should also be tested: passive wrist extension should flex the fingers if tendons are intact. I would test first dorsal interosseous and thumb adduction for ulnar nerve function. **Additional Imaging:** Ultrasound or MRI would assess FDP tendon integrity before surgery. This significantly guides operative planning. **Surgical Management:** Hook excision is required for symptomatic nonunion - conservative treatment will not achieve union at 4 months. If FDP is intact, I would perform excision alone, smoothing the base to protect the remaining tendons. If FDP is ruptured, I would add tendon reconstruction. **Tendon Reconstruction Options:** - FDS to FDP transfer (most common) - Tendon grafting with palmaris longus - Side-to-side repair to adjacent FDP if gap is small **Prognosis:** Hook excision alone has excellent outcomes. If tendon repair is needed, DIP flexion may not fully recover and return to competitive tennis may be affected.
KEY POINTS TO SCORE
20% of untreated nonunions develop FDP rupture
Test DIP flexion with PIP stabilized to assess FDP
Hook excision is treatment of choice for nonunion
Tendon reconstruction if rupture confirmed
COMMON TRAPS
✗Attempting conservative treatment for established nonunion
✗Not assessing tendon integrity before surgery
✗Missing subtle ulnar nerve motor weakness
LIKELY FOLLOW-UPS
"What tendon reconstruction options exist?"
"What is the expected outcome after FDS-to-FDP transfer?"
"How would you counsel about return to competitive tennis?"
VIVA SCENARIOChallenging
High-Energy Hamate Body Fracture
EXAMINER
"A 40-year-old punches a wall and presents with dorsal hand swelling and unable to make a fist. X-rays show a fracture through the hamate body with dorsal subluxation of the 5th CMC joint. Describe the injury pattern and your management."
EXCEPTIONAL ANSWER
This is a hamate body fracture with 5th CMC fracture-dislocation, also called a 'reverse Bennett' pattern. The mechanism is axial load through the metacarpal with dorsal shear force. **Associated Injuries to Assess:** I would assess 4th CMC joint stability, as often both ring and small CMC joints are affected. I would evaluate the entire ulnar column for metacarpal base fractures, test ulnar nerve function in Guyon's canal (motor and sensory), and check extensor tendons which may be injured with severe displacement. **Imaging:** I would obtain a true lateral view to assess CMC dorsal subluxation, and a CT scan for surgical planning to define fracture configuration and articular involvement. A 30-degree pronated oblique view also highlights the CMC joints. **Treatment - Surgical:** This injury requires ORIF. Through a dorsal approach to the CMC joints, I would perform ORIF of the hamate body with K-wires (1.1mm) or mini screws depending on fragment size. I would reduce the CMC joint and stabilize with transarticular K-wires. Any associated metacarpal fractures should be addressed at the same surgery. **Postoperative Protocol:** Splint for 2 weeks, then hand-based thermoplastic. K-wire removal at 6 weeks once healing is confirmed on radiographs. Protected mobilization, avoiding heavy grip for 8-12 weeks. **Long-term Outcomes:** Good union is expected with adequate ORIF. CMC arthrosis may develop over years, and the patient should be counseled about this. Grip strength usually recovers well.
KEY POINTS TO SCORE
Body fracture with CMC dislocation = 'reverse Bennett'
Assess 4th and 5th CMC joints and ulnar nerve
ORIF with K-wires or mini screws required
CMC arthrosis is potential long-term complication
COMMON TRAPS
✗Missing associated 4th CMC injury
✗Not obtaining true lateral to assess subluxation
✗Attempting non-operative management for displaced pattern
LIKELY FOLLOW-UPS
"What approach would you use for hamate body ORIF?"
"When would you remove K-wires?"
"What would you do for late CMC arthrosis?"
MCQ Practice Points
High-Yield MCQ Facts
- Hook forms radial wall of Guyon's canal (ulnar nerve at risk)
- Hook also forms ulnar border of carpal tunnel (median nerve)
- CT sensitivity 95-100% vs X-ray sensitivity 50%
- 50% nonunion rate with conservative treatment
- 20% FDP rupture rate with untreated nonunion
Common MCQ Traps
- Hook is radial to pisiform, not ulnar (2cm distal and radial)
- Motor branch of ulnar nerve at risk, NOT sensory
- X-rays are often normal with hook fractures
- Body fractures need ORIF, hook fractures often need excision
- Grip sports (golf, tennis) cause hook, not body fractures
Sample MCQ Concepts
Key Differentiators for MCQs
| Question Type | Key Point to Remember |
|---|---|
| Best imaging for hook fracture? | CT scan (gold standard) - X-rays miss 50% |
| Treatment for symptomatic nonunion? | Hook excision - not conservative, not ORIF |
| Which nerve branch at risk? | Motor branch of ulnar nerve (Zone II - around hook) |
| Return to sport timeline? | 6-8 weeks after excision |
| Most common mechanism? | Direct blow from sports equipment (golf club) |
| Tendon at risk for rupture? | FDP to ring and small fingers |
| Location of hook tenderness? | 2cm distal AND RADIAL to pisiform |
Imaging Question
Q: A golfer presents with hypothenar pain after hitting the ground during a swing. Plain radiographs are normal. What is the best next investigation?
A: CT scan of the wrist. Hook of hamate fractures are notoriously difficult to visualize on plain radiographs (50% sensitivity). CT has 95-100% sensitivity for hook fractures and is the gold standard imaging modality.
Anatomy Question
Q: Which neural structure passes through Guyon's canal and is most at risk with hook of hamate fractures?
A: The motor branch of the ulnar nerve (deep branch). The hook of hamate forms the radial wall of Guyon's canal. Injury causes weakness of intrinsic muscles (interossei, hypothenar muscles) without sensory loss in Zone II injuries.
Treatment Question
Q: A baseball player presents 6 weeks after injury with persistent hypothenar pain. CT confirms hook of hamate nonunion. What is the recommended treatment?
A: Hook excision. Hook of hamate nonunion has a 50% rate with conservative management. Excision reliably resolves symptoms with excellent outcomes, allows return to sport in 6-8 weeks, and eliminates the risk of FDP tendon rupture from the sharp nonunion fragment.
Complication Question
Q: What tendon is at risk of rupture with an untreated hook of hamate fracture, and what is the reported rupture rate?
A: The flexor digitorum profundus (FDP) tendons to the ring and small fingers are at risk due to their close proximity to the hook. Untreated nonunion has a 20% FDP rupture rate due to attrition from the sharp fracture fragment.
Classification Question
Q: What distinguishes hook of hamate fractures from body of hamate fractures in terms of mechanism and treatment?
A: Hook fractures result from direct impact during grip sports (golf, baseball) and are often treated with excision if symptomatic or nonunion develops. Body fractures result from high-energy trauma, often with associated CMC injuries, and require ORIF to restore carpometacarpal articulation.
Clinical Examination Question
Q: Where is the hook of hamate palpated on clinical examination?
A: The hook is palpated 2cm distal AND radial to the pisiform. It forms the ulnar border of the carpal tunnel and the radial wall of Guyon's canal. Point tenderness at this location with grip weakness is highly suggestive of hook fracture.
Australian Context
Epidemiology:
- Golf and racquet sports common in Australian population
- Rugby league and rugby union: less common cause (different grip mechanics)
- Increasing recognition due to improved imaging access
- Many presentations through sports medicine clinics
Management Considerations:
- CT readily available in metropolitan areas - should be obtained for clinical suspicion
- Private hand surgery access varies by region
- Public hospital wait times may delay treatment for non-urgent cases
- Early referral important to prevent complications
Australian Exam Context
In the Australian Orthopaedic exam setting, be prepared to:
- Discuss the role of CT imaging - readily available and should be used liberally
- Know hook excision technique - commonly performed, may be asked in viva
- Understand return to sport protocols - relevant for sports medicine interface
- Recognize the delayed presentation pattern - commonly seen in Australian practice
- Discuss FDP tendon rupture as a preventable complication with early diagnosis
Key Australian Practice Points:
- High index of suspicion in grip-sport athletes presenting with hypothenar pain
- Do not delay CT if clinical suspicion exists despite normal X-rays
- Early surgical consultation for confirmed fractures
- Hook excision is well-established procedure with excellent outcomes
Hamate Fractures - Exam Day Essentials
High-Yield Exam Summary
Anatomy Points
- •Hook = radial wall of Guyon's canal + ulnar pillar of carpal tunnel
- •Motor branch of ulnar nerve curves around hook - intrinsic weakness if injured
- •FDP to ring and small fingers pass over hook - rupture risk 20% if nonunion
- •Pisohamate ligament attaches proximally - transmits FCU force
Clinical Keys
- •Hook tenderness: 2cm distal and RADIAL to pisiform (not ulnar)
- •Pull test: resisted DIP flexion of ring/small fingers causes hook pain
- •Test FDP function at every visit - rupture is late complication
- •Ulnar motor testing: 1st dorsal interosseous and thumb adduction
Imaging
- •Standard X-rays miss 50% of hook fractures - carpal tunnel view better
- •CT is GOLD STANDARD - 100% sensitivity, get if clinical suspicion
- •MRI for stress fractures or occult injuries
- •Nonunion on CT: sclerotic margins, gap, cyst formation
Hook Treatment
- •Conservative: 50% nonunion rate - reserved for acute, non-displaced only
- •Excision: gold standard for symptomatic nonunion, 85-95% return to sport
- •ORIF: option for acute base fractures, 75-85% union rate
- •Return to grip sports: 6-8 weeks after excision
Body Treatment
- •ORIF required for displaced body fractures
- •Address CMC joint stability (often associated fracture-dislocation)
- •K-wires or mini screws depending on fragment size
- •Watch for long-term CMC arthrosis
Complications to Know
- •FDP rupture - 20% of nonunions, small finger most common
- •Ulnar motor branch injury - Zone II (around hook) most common
- •Nonunion - 50% with conservative treatment of hook fractures
- •Grip weakness after excision - 80-90% of contralateral (well tolerated)