High-yield overview

Nightstick Fracture | Direct Blow | Nonoperative vs ORIF

DirectBlow mechanism

50%Distal third location

10mmDisplacement threshold for ORIF

HighUnion rate nonoperative

TREATMENT DECISION

Minimally displaced

PatternLess than 50% displacement, less than 10° angulation

TreatmentFunctional bracing

Moderately displaced

Pattern50% displacement or 10-15° angulation

TreatmentConsider ORIF

Significantly displaced

PatternGreater than 50% or greater than 15° angulation

TreatmentORIF recommended

Open fracture

PatternAny displacement

TreatmentSurgical debridement + ORIF

Critical Must-Knows

Nightstick fracture = isolated ulna shaft from direct blow (defensive mechanism)
EXCLUDE Monteggia (check radial head position on all views)
Nonoperative threshold: less than 50% displacement, less than 10° angulation
ORIF with 3.5mm DCP plate - 6+ cortices each side
High union rate both operative and nonoperative

Clinical Pearls

"
ALWAYS check PRUJ - rule out Monteggia lesion
"
Functional bracing allows early motion
"
Plate fixation is gold standard for displaced
"
Refracture risk higher with plate removal

Critical Exam Concepts

Rule Out Monteggia

ALWAYS check radial head. An isolated ulna fracture is NOT Monteggia. Get proper views including elbow. A line through radial neck should bisect capitellum on ALL views (radiocapitellar line).

Direct Blow History

Classic mechanism. Patient raises arm to defend against blow (assault, fall onto object). The subcutaneous position of the ulna makes it vulnerable. Ask about mechanism carefully.

Nonoperative Criteria

Strict criteria. Less than 50% displacement, less than 10° angulation in proximal 2/3 or less than 15° in distal 1/3. Middle/distal third location. Functional brace allows early motion.

ORIF Threshold

Greater than 50% displacement or significant angulation. Use 3.5mm DCP plate with 6+ cortices each side. Compression plating standard technique.

Isolated Ulna Fracture Quick Decision

Displacement	Angulation	Location	Treatment
Less than 50%	Less than 10°	Middle/distal	Functional brace
50%	10-15°	Any	Borderline - consider ORIF
Greater than 50%	Greater than 15°	Proximal	ORIF recommended
Any	Any	Open fracture	ORIF + debridement

Mnemonic

NIGHTNightstick Fracture Features

N	Not Monteggia Confirm radial head located
I	Isolated ulna Single bone injury
G	Guard position Defensive arm raised
H	Hit directly Direct blow mechanism
T	Treatment by displacement Brace or ORIF

N	Not Monteggia Confirm radial head located	H	Hit directly Direct blow mechanism
I	Isolated ulna Single bone injury	T	Treatment by displacement Brace or ORIF
G	Guard position Defensive arm raised

Hook:NIGHT stick fracture from a NIGHT time assault!

Mnemonic

PLATEORIF Indications

P	Proximal third Higher union issues
L	Large displacement (greater than 50%) Unstable pattern
A	Angulation greater than 15° Malunion risk
T	Two bone involvement Not truly isolated
E	Expected compliance poor Brace won't work

P	Proximal third Higher union issues	T	Two bone involvement Not truly isolated
L	Large displacement (greater than 50%) Unstable pattern	E	Expected compliance poor Brace won't work
A	Angulation greater than 15° Malunion risk

Hook:PLATE the ulna when criteria met!

Mnemonic

SAFENonoperative Criteria

S	Stable pattern Less than 50% displacement
A	Angulation minimal Less than 10-15 degrees
F	Functional brace compliant Patient can manage
E	Exclude Monteggia Radial head in joint

S	Stable pattern Less than 50% displacement	F	Functional brace compliant Patient can manage
A	Angulation minimal Less than 10-15 degrees	E	Exclude Monteggia Radial head in joint

Hook:SAFE for functional bracing!

Overview and Epidemiology

Why 'Nightstick' Fracture?

Historical name. Called nightstick fracture because the mechanism is typically a direct blow to the raised forearm, as when defending against an assault with a nightstick (baton). The subcutaneous ulna border is vulnerable to direct impact.

Epidemiology

2-5% of forearm fractures
Bimodal: young males (assault), elderly (falls)
More common in males
Middle to distal third most common

Mechanism

Direct blow to subcutaneous ulna border
Defensive arm position (guard)
Fall onto hard edge
Sports (hockey stick, bat)

Anatomy and Biomechanics

Ulna Shaft

Position: The posterior border is subcutaneous throughout its length, making it vulnerable to direct trauma.

Cross-section: Triangular proximally, becomes more rounded distally.

Interosseous membrane: Connects ulna to radius. Important for load transfer and forearm stability. Disruption creates longitudinal instability (Essex-Lopresti).

Classification

OTA/AO Classification

22-A1: Simple fracture of ulna only.

22-B1: Wedge fracture of ulna only.

22-C1: Complex fracture of ulna only.

The classification guides complexity but treatment is primarily based on displacement and angulation.

Clinical Assessment

History

Mechanism (direct blow vs fall)
Assault or accident
Location and timing of impact
Previous forearm injury
Hand dominance

Examination

Inspect for deformity, swelling
Palpate entire ulna and radius
Check DRUJ and PRUJ
Test forearm rotation
Neurovascular exam

Must Exclude Monteggia

An isolated ulna fracture is NOT a Monteggia lesion. Always check the proximal radioulnar joint (PRUJ). The radiocapitellar line (line through radial shaft/neck) should bisect the capitellum on ALL views. If the radial head is dislocated, it is a Monteggia fracture-dislocation, not an isolated ulna fracture.

Differential Diagnosis

Distinguishing Isolated Ulnar Shaft Fracture from Mimics

Diagnosis	Key Distinguishing Feature	Pitfall if Missed
Isolated ulnar shaft fracture	Single ulna fracture, radiocapitellar line intact, DRUJ congruent	—
Monteggia fracture-dislocation	Ulna fracture PLUS radial head dislocation (radiocapitellar line broken)	Missed radial head dislocation leads to chronic instability and poor function
Both-bone forearm fracture	Radius AND ulna both fractured	Treating as isolated underestimates instability
Galeazzi fracture	Radial shaft fracture with DRUJ disruption (not ulnar shaft)	Different injury; DRUJ must be reduced
Essex-Lopresti injury	Radial head fracture, IOM disruption, DRUJ instability (longitudinal)	Missed longitudinal forearm instability
Pathological fracture	Low-energy mechanism, lytic/sclerotic lesion on imaging	Fixing without addressing underlying lesion

Investigations

Essential Views

Forearm AP and Lateral: Both bones, full length.

Include elbow: Essential to assess radiocapitellar alignment and exclude Monteggia.

Include wrist: Assess DRUJ for longitudinal instability.

Measurements: Displacement as percentage of bone width, angulation in degrees.

Management

Functional Bracing

Indications: Less than 50% displacement, less than 10° angulation (proximal/middle), less than 15° angulation (distal), intact radiocapitellar joint.

Protocol: Initial long-arm splint 1-2 weeks. Convert to functional brace. Allow elbow and wrist motion. Serial X-rays at 2, 4, 6 weeks.

Expected outcomes: Union in 8-12 weeks. Good functional results if criteria met.

Failure: If displacement increases or patient non-compliant, convert to ORIF.

Functional Bracing Rationale

Why functional bracing works: The interosseous membrane and surrounding soft tissues provide stability. Early motion prevents stiffness while allowing fracture healing through micromotion. The ulna is primarily a stabilizer (not weight-bearing like radius), so moderate displacement is tolerated.

Advantages

Avoids surgery complications
Lower infection risk
Early joint motion
Cost-effective
No hardware removal needed

Requirements

Patient compliance critical
Regular follow-up essential
Serial radiographs needed
Accept some residual deformity
Longer time to union

Plate Removal Consideration

Refracture after plate removal is a recognized complication (up to 20% in some series). Counsel patients about this risk. If removing plate, protect arm for 6-12 weeks after removal.

Surgical Technique

Posterior Approach to Ulna

Position: Supine with arm across chest, or lateral with arm on table.

Incision: Direct posterior over subcutaneous ulna border.

Internervous plane: Between ECU (posterior interosseous) and FCU (ulnar nerve). The ulna is subcutaneous - minimal dissection needed.

Key structure: Ulnar nerve is anterior and does not need to be identified for shaft fractures.

Complications

Complication	Incidence	Management
Nonunion	5-10% (nonoperative)	ORIF with bone graft
Malunion	Variable	Osteotomy if symptomatic
Refracture post plate removal	Up to 20%	Protect arm, consider leaving plate
Infection	1-2% (operative)	Antibiotics, debridement
Hardware prominence	Common	Plate removal after union

Postoperative Care

Rehabilitation Protocol

Week 0-2Immobilization

Splint or brace. Wound care. Finger and shoulder ROM.

Week 2-6Early Motion

Begin elbow and wrist ROM. Gentle forearm rotation. Sling for comfort.

Week 6-12Progressive ROM

Full ROM goal. Light strengthening. X-ray to confirm healing.

Month 3-6Return to Activity

Progressive strengthening. Return to work based on healing. Sports at 4-6 months.

Outcomes and Prognosis

Outcome Factors

Favorable: Distal third, minimal displacement, good compliance, anatomic reduction.

Unfavorable: Proximal third, comminution, delayed treatment, smoking.

Controversies and Areas of Uncertainty

The 50% / 10° Threshold

The classic nonoperative criteria (under 50% displacement, under 10° angulation) come from Sarmiento-era series. Newer data (Coulibaly 2015) link angulation of 8° or more and any secondary displacement to malunion, nonunion and failure to return to prior activity, suggesting the traditional limits may be too permissive for active patients.

Moderately Displaced Fractures

Fractures near the 50% threshold are genuinely contested. Ali (2019) reported 5 of 10 nonoperative cases failed, yet operative treatment adds surgical and hardware risk. No RCT resolves this; decisions are individualised by age, demand, compliance and follow-up reliability.

Routine Bone Grafting

Anderson's historical recommendation to graft minor comminution is no longer supported: Ring (2005) found bone grafting did not reduce nonunion in comminuted forearm fractures. Bridge plating with biological technique is now preferred.

Plate Removal

Whether to remove a subcutaneous, prominent ulnar plate is debated. Removal relieves symptoms but carries a refracture risk concentrated at the plate ends; many surgeons leave asymptomatic plates in situ and, if removing, protect the limb afterwards.

Evidence Base and Key Studies

Functional Bracing - Landmark Series (Sarmiento)

Sarmiento A, Latta LL, Zych G, et al. • J Orthop Trauma (1998)

Key Findings:

444 isolated ulnar shaft fractures braced; 287 (65%) followed up
Union in 99% of fractures; mean shortening only 1.1 mm
Mean final radial and dorsal angulation 5° each
Good-to-excellent function in more than 96% (greatest pronation loss in proximal-third)

Clinical Implication: Functional bracing that permits full joint motion gives a 99% union rate for minimally displaced isolated ulnar shaft fractures and is the benchmark nonoperative reference.

Limitation: Retrospective; 35% lost to follow-up; proximal-third fractures had the greatest pronation loss.

Verify on PubMed (PMID 9715450)

Compression Plating of Forearm Diaphysis (Anderson)

Anderson LD, Sisk D, Tooms RE, Park WI. • J Bone Joint Surg Am (1975)

Key Findings:

330 acute diaphyseal radius/ulna fractures plated; 137 isolated/combined ulna fractures
Union rate 96.3% for the ulna and 97.9% for the radius
Established ASIF compression plating as the standard for forearm diaphyseal fractures
Iliac bone graft used for severely comminuted patterns (later questioned)

Clinical Implication: Rigid compression plating restores forearm anatomy with high union rates and remains the reference operative technique for displaced ulnar shaft fractures.

Limitation: Historical cohort; routine bone grafting of comminution no longer supported.

Verify on PubMed (PMID 1091653)

Bone Graft Not Required for Comminution (Ring)

Ring D, Rhim R, Carpenter C, Jupiter JB. • J Trauma (2005)

Key Findings:

41 comminuted both-bone forearm fractures plated with 3.5/4.5 mm DCP (6+ holes)
Nonunion in 12% (5 patients)
Bone grafting NOT associated with lower nonunion (OR 0.98, 95% CI 0.15-6.42)
Open fracture, multiple injury, ipsilateral injury also not significant

Clinical Implication: Modern plating of comminuted forearm fractures does not mandate routine bone grafting, overturning earlier Anderson-era practice.

Limitation: Small retrospective cohort; both-bone fractures rather than isolated ulna.

Verify on PubMed (PMID 16294088)

Operative vs Nonoperative Nightstick Outcomes (Ali)

Ali M, Clark DI, Tambe A. • Acta Medica (Hradec Kralove) (2019)

Key Findings:

52 isolated ulnar shaft fractures; 42 ORIF (incl. 6 open) vs 10 nonoperative
5 of 10 nonoperative cases failed and required more follow-up visits
ORIF gave satisfactory outcome with early non-load-bearing mobilisation
Fractures with less than 50% displacement individualised by age, function, compliance

Clinical Implication: Displacement near the 50% threshold should be decided case-by-case; nonoperative care carries a meaningful failure rate.

Limitation: Small single-centre retrospective series.

Verify on PubMed (PMID 30931892)

Displacement Drives Complications (Coulibaly)

Coulibaly MO, Jones CB, Sietsema DL, Schildhauer TA. • Injury (2015)

Key Findings:

70 isolated ulnar shaft fractures; 33 nonoperative vs 37 ORIF
14 nonunions and 17 malunions overall; nonoperative significantly associated with both
Angulation of 8° or more linked to failure to return to prior activity level
Secondary displacement greater than 2 mm contributed to malunion and nonunion

Clinical Implication: Even modest angulation (8° or more) and any secondary displacement worsen outcome, supporting a lower operative threshold than older 50%/10° rules imply.

Limitation: Level III case-control; high-energy mechanism predominated (85.7%).

Verify on PubMed (PMID 25843885)

Refracture After Plate Removal (Lindgren)

Lindgren AM, Sendek G, Manhard CE, et al. • J Pediatr Orthop (2023)

Key Findings:

349 surgically fixed forearm fractures; subsequent fracture rate 5-11%
Plate refractures 10.9% vs flexible-nail 5.1%
90% of plate refractures occurred at the proximal or distal plate edge
90% of plate refractures required revision surgery

Clinical Implication: Subcutaneous forearm plates carry a real refracture risk concentrated at plate ends; counsel patients and protect the limb if hardware is removed.

Limitation: Paediatric cohort; refracture data extrapolated cautiously to adults.

Verify on PubMed (PMID 36863879)

Exam Viva Scenarios

Use these scenarios to practise clinical reasoning and management decisions

CLINICAL SCENARIOStandard

Scenario 1: Nightstick Fracture

CLINICAL PROMPT

"A 28-year-old man presents after an altercation where he raised his arm to defend himself. X-rays show an isolated mid-shaft ulna fracture with 30% displacement and 5 degrees of angulation. How would you manage this?"

PRACTICAL APPROACH

This is a classic nightstick fracture - an isolated ulna shaft fracture from a direct blow in a defensive position. Before making a treatment decision, I must confirm this is truly an isolated ulna fracture by verifying the radial head is located on all views - a line through the radial shaft should bisect the capitellum to exclude Monteggia. Assuming the PRUJ and DRUJ are intact, this fracture meets criteria for nonoperative management: 30% displacement is less than the 50% threshold, and 5 degrees angulation is less than 10 degrees. My treatment would be initial immobilization in a long-arm splint for 1-2 weeks for comfort, then transition to a functional brace that allows elbow and wrist motion while supporting the fracture. I would obtain serial X-rays at 2, 4, and 6 weeks to monitor for displacement. Expected union is 8-12 weeks. I would counsel the patient about the importance of compliance with the brace and follow-up, as well as avoiding further trauma. The prognosis is excellent with approximately 90% union rate for fractures meeting these criteria.

KEY CLINICAL POINTS

Confirm radial head located - exclude Monteggia

30% displacement and 5° angulation = nonoperative criteria met

Functional bracing after initial splint

Serial X-rays to monitor

90% union rate expected

COMMON PITFALLS

Not checking radiocapitellar line

Operating on a minimally displaced fracture

Not counseling about compliance

Missing DRUJ injury

FURTHER QUESTIONS

"What if displacement was 60%?"

"What if the radial head was dislocated?"

"What if the fracture was proximal third?"

CLINICAL SCENARIOStandard

Scenario 2: Displaced Fracture

CLINICAL PROMPT

"A 35-year-old woman falls onto a metal railing, striking her forearm. X-rays show an isolated ulna fracture with 75% displacement and 20 degrees of angulation. How would you treat this?"

PRACTICAL APPROACH

This isolated ulna fracture exceeds the nonoperative thresholds considerably - 75% displacement is greater than 50% and 20 degrees angulation is greater than 15 degrees. I would recommend ORIF. Again, I must first confirm this is isolated by checking the radiocapitellar line on all views and assessing the DRUJ. My surgical approach would be direct posterior over the subcutaneous ulna border. I would use a 3.5mm narrow DCP or LCP, typically 8-10 holes in length. Fixation goals are minimum 6 cortices (3 screws) on each side of the fracture. For this oblique/displaced pattern, I would use a lag screw through the plate if the fracture geometry allows, then neutralization/compression mode. Post-operatively, she would be in a removable splint for comfort, with early ROM exercises starting at 2 weeks. I would obtain X-rays at 2, 6, and 12 weeks. Expected union is 10-14 weeks. I would counsel her about possible hardware prominence given the subcutaneous position, and discuss that if plate removal is desired, it should wait until at least 18-24 months and carries a refracture risk.

KEY CLINICAL POINTS

75% displacement and 20° = exceeds nonoperative criteria

ORIF recommended

3.5mm DCP or LCP, 6+ cortices each side

Lag screw if fracture pattern allows

Counsel about hardware prominence and refracture risk

COMMON PITFALLS

Attempting nonoperative for significantly displaced fracture

Inadequate fixation (fewer than 6 cortices)

Not checking radiocapitellar alignment

Removing plate too early

FURTHER QUESTIONS

"How would you approach the ulna surgically?"

"What if the fracture was comminuted?"

"When would you consider plate removal?"

CLINICAL SCENARIOChallenging

Scenario 3: Proximal Third Fracture

CLINICAL PROMPT

"An isolated ulna fracture in the proximal third with 40% displacement. The radial head is confirmed located. How would your management differ from a mid-shaft fracture?"

PRACTICAL APPROACH

This is an important distinction. Although 40% displacement is technically less than the 50% threshold for nonoperative treatment, I would have a lower threshold for ORIF in a proximal third fracture. There are several reasons: First, the proximal ulna has deforming forces from muscle attachments that make maintaining alignment more difficult. Second, studies have shown higher nonunion rates with nonoperative treatment of proximal third fractures. Third, the functional implications of malunion are greater proximally due to effects on the elbow and pronation-supination arc. I would discuss both options with the patient - nonoperative with very close monitoring and strict brace compliance, versus ORIF which provides reliable alignment and allows early motion. Given the borderline displacement and proximal location, I would lean toward recommending ORIF for this patient, especially if they are young and active or have high functional demands. If the patient strongly prefers nonoperative treatment, I would accept that with understanding of the higher risk of complications and need for very close follow-up with low threshold to convert to surgery if alignment is lost.

KEY CLINICAL POINTS

Proximal third = lower threshold for ORIF

Higher nonunion rate with nonoperative proximally

Deforming muscle forces

40% displacement is borderline - location tips decision

Shared decision-making with patient

COMMON PITFALLS

Treating all isolated ulna fractures the same regardless of location

Being too rigid with 50% threshold

Not discussing treatment options

Ignoring prognostic factors

FURTHER QUESTIONS

"What muscles attach to the proximal ulna?"

"What is the nonunion rate for proximal third fractures?"

"How would you approach proximal ulna surgically?"

CLINICAL SCENARIOCritical

Scenario 4: Open Fracture

CLINICAL PROMPT

"A 42-year-old motorcyclist presents with a Gustilo grade II open isolated ulna fracture. The radial head is confirmed located. How would you manage this injury?"

PRACTICAL APPROACH

This is an open isolated ulna fracture requiring urgent surgical management regardless of displacement. My priorities follow ATLS principles first, then addressing the open fracture. Immediate management includes IV antibiotics - cefazolin 2g as first line, adding gentamicin if contamination significant. Tetanus prophylaxis if needed. The wound needs thorough irrigation and debridement in theatre ideally within 6 hours. After debridement, I would perform definitive fixation with ORIF using a 3.5mm DCP or LCP. The approach would be through or adjacent to the wound, extending as needed for adequate exposure. I would achieve rigid fixation with 6+ cortices each side. The wound would be managed based on its condition - if clean after debridement and good soft tissue coverage, primary closure or delayed primary closure. If contaminated or significant soft tissue loss, leave open with planned second look at 48-72 hours. Post-operatively, IV antibiotics for 24-48 hours (grade II), regular wound inspections, and early motion once soft tissues allow. I would counsel about higher infection risk, possible need for further surgery, and longer healing time compared to closed fractures.

KEY CLINICAL POINTS

Open fracture = operative regardless of displacement

Antibiotics, debridement, tetanus within 6 hours

ORIF with adequate fixation

Wound management based on grade and contamination

Higher complication rate counseling

COMMON PITFALLS

Delaying surgery for 'minimally displaced' pattern

Inadequate debridement

Primary closure of contaminated wound

Not considering soft tissue coverage

FURTHER QUESTIONS

"What antibiotics for a grade IIIB fracture?"

"When would you consider external fixation?"

"How do you manage soft tissue loss over ulna?"

MCQ Practice Points

Displacement Threshold

Q: What is the displacement threshold for nonoperative treatment of isolated ulna fractures? A: Less than 50% of bone width. Beyond this, ORIF is recommended.

Angulation Threshold

Q: What angulation is acceptable for nonoperative treatment? A: Less than 10 degrees in proximal/middle third, up to 15 degrees in distal third.

Monteggia Exclusion

Q: What must be confirmed before diagnosing an isolated ulna fracture? A: Radial head is located. Check radiocapitellar line on all views to exclude Monteggia lesion.

Plate Fixation

Q: What is the minimum fixation required for ulna shaft ORIF? A: 6 cortices (3 screws) on each side of the fracture with a 3.5mm DCP or LCP.

Refracture Risk

Q: What is a significant risk after plate removal from the ulna? A: Refracture (up to 20%). Recommend waiting 18-24 months before removal if indicated.

Nightstick Mechanism

Q: What is the mechanism of a nightstick fracture? A: Direct blow to the subcutaneous ulna border, typically when arm is raised in defense.

Guidelines, Registries & Global Practice

Global Epidemiology

Isolated ulnar shaft fractures are uncommon (a small fraction of forearm fractures) and remain under-studied
Bimodal: young men (assault, the classic "nightstick" mechanism) and older adults (low-energy falls)
High-energy mechanism predominated (85.7%) in one Level I trauma-centre series of 70 cases (Coulibaly 2015)
Mechanism varies by region: interpersonal violence in urban trauma centres, falls in ageing populations, sport elsewhere

Registry & Evidence Gap

No dedicated arthroplasty-style registry exists for diaphyseal forearm fractures
Evidence base is small retrospective series and case-control studies, not RCTs
No high-level consensus on the exact operative threshold for moderately displaced fractures
This makes individualised, shared decision-making essential

Society Guidance & Practice Comparison

Body / Region	Position on Isolated Ulnar Shaft Fractures
AO Foundation / OTA	Classify as 2U2 (ulna diaphysis); plate compression for simple, bridge plating for comminuted; minimum 6 cortices each side
AAOS (US) / UK BOA practice	Nonoperative bracing for minimally displaced (under 50% displacement, under 10° angulation, radial head reduced); ORIF for displaced or proximal-third
EFORT / European literature	Lower angulation tolerance suggested (8° or more linked to worse function); favour fixation when displacement near threshold
Consistent global principle	Exclude Monteggia in every case (radiocapitellar line on dedicated elbow views) before labelling 'isolated'

High-Resource Settings

Prefabricated functional braces readily available for nonoperative pathway
Locking plates (LCP) stocked for osteoporotic bone
Early supervised hand therapy and serial imaging routine
Day-case ORIF feasible with image intensifier

Limited-Resource Settings

Custom moulded casts/braces substitute for prefabricated braces
Standard (non-locking) DCP plating remains effective and lower cost
Reliable follow-up for serial radiographs may favour definitive fixation when displacement is borderline
Implant removal may be deferred indefinitely to conserve theatre resources and avoid refracture risk

Non-Accidental Injury

Safeguarding remains global. In a child or in any patient where the history does not match the injury, an isolated ulnar fracture should prompt consideration of non-accidental injury and appropriate safeguarding pathways, irrespective of healthcare system.

ISOLATED ULNA FRACTURES

Clinical summary

Key Features

•Nightstick = direct blow mechanism
•Must exclude Monteggia (check PRUJ)
•Subcutaneous position vulnerable
•Middle/distal third most common

Nonoperative Criteria

•Less than 50% displacement
•Less than 10° angulation prox/mid
•Less than 15° angulation distal
•Radial head located

ORIF Indications

•Greater than 50% displacement
•Greater than 15° angulation
•Proximal third (lower threshold)
•Open fractures

Operative Technique

•Posterior approach to ulna
•3.5mm DCP or LCP
•6+ cortices each side
•Lag screw if oblique

Outcomes

•95%+ union rate (ORIF)
•90% union rate (nonoperative)
•Refracture risk with plate removal
•Prox third higher complications

Displacement

Angulation

Location

Treatment

Less than 50%

Less than 10°

Middle/distal

Functional brace

50%

10-15°

Any

Borderline - consider ORIF

Greater than 50%

Greater than 15°

Proximal

ORIF recommended

Any

Open fracture

ORIF + debridement

Diagnosis

Key Distinguishing Feature

Pitfall if Missed

Isolated ulnar shaft fracture

Single ulna fracture, radiocapitellar line intact, DRUJ congruent

—

Monteggia fracture-dislocation

Ulna fracture PLUS radial head dislocation (radiocapitellar line broken)

Missed radial head dislocation leads to chronic instability and poor function

Both-bone forearm fracture

Radius AND ulna both fractured

Treating as isolated underestimates instability

Galeazzi fracture

Radial shaft fracture with DRUJ disruption (not ulnar shaft)

Different injury; DRUJ must be reduced

Essex-Lopresti injury

Radial head fracture, IOM disruption, DRUJ instability (longitudinal)

Missed longitudinal forearm instability

Pathological fracture

Low-energy mechanism, lytic/sclerotic lesion on imaging

Fixing without addressing underlying lesion

Complication

Incidence

Management

Nonunion

5-10% (nonoperative)

ORIF with bone graft

Malunion

Variable

Osteotomy if symptomatic

Refracture post plate removal

Up to 20%

Protect arm, consider leaving plate

Infection

1-2% (operative)

Antibiotics, debridement

Hardware prominence

Common

Plate removal after union

Functional Bracing - Landmark Series (Sarmiento)

Sarmiento A, Latta LL, Zych G, et al. • J Orthop Trauma (1998)

Key Findings:

444 isolated ulnar shaft fractures braced; 287 (65%) followed up
Union in 99% of fractures; mean shortening only 1.1 mm
Mean final radial and dorsal angulation 5° each
Good-to-excellent function in more than 96% (greatest pronation loss in proximal-third)

Clinical Implication: Functional bracing that permits full joint motion gives a 99% union rate for minimally displaced isolated ulnar shaft fractures and is the benchmark nonoperative reference.

Limitation: Retrospective; 35% lost to follow-up; proximal-third fractures had the greatest pronation loss.

Verify on PubMed (PMID 9715450)

Compression Plating of Forearm Diaphysis (Anderson)

Anderson LD, Sisk D, Tooms RE, Park WI. • J Bone Joint Surg Am (1975)

Key Findings:

330 acute diaphyseal radius/ulna fractures plated; 137 isolated/combined ulna fractures
Union rate 96.3% for the ulna and 97.9% for the radius
Established ASIF compression plating as the standard for forearm diaphyseal fractures
Iliac bone graft used for severely comminuted patterns (later questioned)

Clinical Implication: Rigid compression plating restores forearm anatomy with high union rates and remains the reference operative technique for displaced ulnar shaft fractures.

Limitation: Historical cohort; routine bone grafting of comminution no longer supported.

Verify on PubMed (PMID 1091653)

Bone Graft Not Required for Comminution (Ring)

Ring D, Rhim R, Carpenter C, Jupiter JB. • J Trauma (2005)

Key Findings:

41 comminuted both-bone forearm fractures plated with 3.5/4.5 mm DCP (6+ holes)
Nonunion in 12% (5 patients)
Bone grafting NOT associated with lower nonunion (OR 0.98, 95% CI 0.15-6.42)
Open fracture, multiple injury, ipsilateral injury also not significant

Clinical Implication: Modern plating of comminuted forearm fractures does not mandate routine bone grafting, overturning earlier Anderson-era practice.

Limitation: Small retrospective cohort; both-bone fractures rather than isolated ulna.

Verify on PubMed (PMID 16294088)

Operative vs Nonoperative Nightstick Outcomes (Ali)

Ali M, Clark DI, Tambe A. • Acta Medica (Hradec Kralove) (2019)

Key Findings:

52 isolated ulnar shaft fractures; 42 ORIF (incl. 6 open) vs 10 nonoperative
5 of 10 nonoperative cases failed and required more follow-up visits
ORIF gave satisfactory outcome with early non-load-bearing mobilisation
Fractures with less than 50% displacement individualised by age, function, compliance

Clinical Implication: Displacement near the 50% threshold should be decided case-by-case; nonoperative care carries a meaningful failure rate.

Limitation: Small single-centre retrospective series.

Verify on PubMed (PMID 30931892)

Displacement Drives Complications (Coulibaly)

Coulibaly MO, Jones CB, Sietsema DL, Schildhauer TA. • Injury (2015)

Key Findings:

70 isolated ulnar shaft fractures; 33 nonoperative vs 37 ORIF
14 nonunions and 17 malunions overall; nonoperative significantly associated with both
Angulation of 8° or more linked to failure to return to prior activity level
Secondary displacement greater than 2 mm contributed to malunion and nonunion

Clinical Implication: Even modest angulation (8° or more) and any secondary displacement worsen outcome, supporting a lower operative threshold than older 50%/10° rules imply.

Limitation: Level III case-control; high-energy mechanism predominated (85.7%).

Verify on PubMed (PMID 25843885)

Refracture After Plate Removal (Lindgren)

Lindgren AM, Sendek G, Manhard CE, et al. • J Pediatr Orthop (2023)

Key Findings:

349 surgically fixed forearm fractures; subsequent fracture rate 5-11%
Plate refractures 10.9% vs flexible-nail 5.1%
90% of plate refractures occurred at the proximal or distal plate edge
90% of plate refractures required revision surgery

Clinical Implication: Subcutaneous forearm plates carry a real refracture risk concentrated at plate ends; counsel patients and protect the limb if hardware is removed.

Limitation: Paediatric cohort; refracture data extrapolated cautiously to adults.

Verify on PubMed (PMID 36863879)

Body / Region

Position on Isolated Ulnar Shaft Fractures

AO Foundation / OTA

Classify as 2U2 (ulna diaphysis); plate compression for simple, bridge plating for comminuted; minimum 6 cortices each side

AAOS (US) / UK BOA practice

Nonoperative bracing for minimally displaced (under 50% displacement, under 10° angulation, radial head reduced); ORIF for displaced or proximal-third

EFORT / European literature

Lower angulation tolerance suggested (8° or more linked to worse function); favour fixation when displacement near threshold

Consistent global principle

Exclude Monteggia in every case (radiocapitellar line on dedicated elbow views) before labelling 'isolated'

Isolated Ulna Fractures (Nightstick Fractures)

Isolated Ulna Fractures (Nightstick Fractures)

TREATMENT DECISION

Critical Must-Knows

Clinical Pearls

Critical Exam Concepts

Rule Out Monteggia

Direct Blow History

Nonoperative Criteria

ORIF Threshold

Isolated Ulna Fracture Quick Decision

NIGHTNightstick Fracture Features

PLATEORIF Indications

SAFENonoperative Criteria

Overview and Epidemiology

Epidemiology

Mechanism

Anatomy and Biomechanics

Ulna Shaft

Load Transfer

Classification

OTA/AO Classification

Location-Based Considerations

Clinical Assessment

History

Examination

Must Exclude Monteggia

Differential Diagnosis

Distinguishing Isolated Ulnar Shaft Fracture from Mimics

Investigations

Essential Views

Radiographic Assessment

Management

Functional Bracing

Advantages

Requirements

ORIF with Plate Fixation

Plate Selection

Screw Strategy

Treatment Decision Tree

Decision Process

Plate Removal Consideration

Surgical Technique

Posterior Approach to Ulna

Plate Fixation

Complications

Postoperative Care

Rehabilitation Protocol

Outcomes and Prognosis

Outcome Factors

Controversies and Areas of Uncertainty

The 50% / 10° Threshold

Moderately Displaced Fractures

Routine Bone Grafting

Plate Removal

Evidence Base and Key Studies

Functional Bracing - Landmark Series (Sarmiento)

Compression Plating of Forearm Diaphysis (Anderson)

Bone Graft Not Required for Comminution (Ring)

Operative vs Nonoperative Nightstick Outcomes (Ali)

Displacement Drives Complications (Coulibaly)

Refracture After Plate Removal (Lindgren)

Exam Viva Scenarios

Scenario 1: Nightstick Fracture

Scenario 2: Displaced Fracture

Scenario 3: Proximal Third Fracture

Scenario 4: Open Fracture

MCQ Practice Points

Guidelines, Registries & Global Practice

Global Epidemiology

Registry & Evidence Gap

Society Guidance & Practice Comparison

High-Resource Settings

Limited-Resource Settings

ISOLATED ULNA FRACTURES

Key Features

Nonoperative Criteria

ORIF Indications

Operative Technique

Outcomes