01Approach to the Critical Patient/attcp31

Key Concepts

›Critical decision point

›Distinguish partial tear (stable, firm endpoint) from complete tear (unstable, no endpoint)

›Complete tears with Stener lesion cannot heal without surgery

›Delay beyond 3-4 weeks from injury worsens surgical outcomes

›Radiograph before stress testing

›Displaced avulsion fracture is a contraindication to stress testing

›Stress testing can displace a fracture fragment and convert a simple to complex injury

›Stener lesion recognition

›UCL displaced superficial to adductor aponeurosis — interposed tissue prevents healing

›Palpable mass on ulnar aspect of MCP joint is pathognomonic

›All confirmed Stener lesions require operative repair

PITFALLS

›Common errors in management

›Performing valgus stress before obtaining radiographs

›Risk of fracture fragment displacement

›AP, lateral, and oblique views required first

›Failing to compare laxity to contralateral thumb

›Congenital ligamentous laxity may give false impression of injury

›Contralateral threshold: >15° difference is significant

›Premature discharge without hand surgery follow-up for complete tears

›Surgery within 3-4 weeks yields best outcomes

›Untreated complete tears lead to chronic instability and MCP osteoarthritis

PEARLS

›Clinical efficiency pearls

›Valgus stress in 30° MCP flexion isolates the proper UCL

›Extension testing adds assessment of the accessory collateral ligament

›Both positions should be tested and documented

02History/hx36

Mechanism and presentation

›Mechanism of injury

›Forced abduction and hyperextension of thumb at MCP joint

›Fall on outstretched hand with thumb abducted — classic skiing injury

›Ball-handling sports: football, basketball, baseball, rugby

›Acute versus chronic injury distinction

›Acute — skier's thumb: single high-energy event

›Chronic — gamekeeper's thumb: repetitive low-grade stress (historical occupational)

›Symptom characterization

›Ulnar-sided thumb pain at MCP joint

›Swelling and ecchymosis over ulnar aspect

›Weakness of pinch and key grip

›Functional limitations

›Inability to pinch or grasp objects

›Worsening instability suggesting complete tear

Risk factors

›Activity-related risks

›Skiing — most common acute mechanism

›Pole strap forces thumb into abduction during falls

›Strapless poles may reduce risk

›Contact and ball sports

›Football, basketball, wrestling, rugby

›Repetitive occupational hand stress

›Patient-level risks

›Prior thumb MCP injury or ligamentous laxity

›Connective tissue disorders (Ehlers-Danlos syndrome)

›Inflammatory arthritis — rheumatoid may cause ligament attenuation

›Conditions affecting healing

03Physical Exam/exam40

Inspection and palpation

›Ulnar MCP joint assessment

›Swelling and ecchymosis over ulnar aspect of thumb MCP joint

›Ecchymosis may track proximally along thenar eminence

›Diffuse swelling may obscure palpable findings

›Palpable Stener nodule

›Displaced UCL stump palpable proximal to expected insertion site

›Pathognomonic for Stener lesion when present

›Point tenderness at UCL insertion on proximal phalanx

›Distinguish from radial-sided tenderness (RCL injury)

›Proximal tenderness suggests avulsion from metacarpal origin

Valgus stress testing

›Stress test protocol

›MCP joint in 30° flexion — tests proper UCL

›Partial tear: laxity <30°, firm endpoint present

›Complete tear: laxity >=30° or >=15° more than contralateral, no endpoint

›MCP joint in full extension — tests accessory collateral ligament

›Additional laxity in extension broadens injury extent

›Compare bilaterally in all cases

›Obtain radiographs before stress testing

›Displaced avulsion fracture is a contraindication

›Stress testing can displace fracture fragments

Functional and neurovascular assessment

›Pinch and grip strength

›Key pinch weakened compared to contralateral side

›Quantify with pinch dynamometer if available

›Severity correlates with degree of UCL disruption

›Grip strength global assessment

04Differential Diagnosis/ddx47

Bony injuries

›Avulsion fracture at UCL insertion

›Base of proximal phalanx — UCL origin avulsion

›ICD-10 S63.641A

›Displaced fragments require surgical fixation

›Bennett fracture

›ICD-10 S62.211A

›Intra-articular fracture-dislocation of first CMC joint

›Pain more proximal, radiograph diagnostic

›Rolando fracture

›ICD-10 S62.221A

›Comminuted variant of Bennett — poor prognosis

›Comminution visible on plain radiograph

›Metacarpal and phalangeal fractures

›Thumb metacarpal shaft fracture

›ICD-10 S62.201A

›Tenderness along shaft, deformity possible

›MCP joint sesamoid fracture

›Volar tenderness localized

›Seen on sesamoid view radiograph

Ligament and tendon injuries

›Radial collateral ligament injury

›RCL injury of thumb MCP

›ICD-10 S63.601A

›Tenderness on radial side, radial stress test positive

›Much less common than UCL injury

›Gamekeeper's thumb — UCL partial tear

›ICD-10 S63.641A

05Laboratory Tests/lt25

Routine labs

›No routine labs for isolated UCL injury

›Isolated ligament injury does not require hematologic workup

›Blood loss insufficient to require CBC

›Renal function not relevant to splinting

›Pre-operative panel only when surgery is planned

›Per institutional protocol

›CBC, coagulation, metabolic panel as indicated

Infection workup

›Inflammatory markers when infection suspected

›Complete blood count

›Leukocytosis supports septic arthritis

›Elevated neutrophil percentage

›CRP and ESR

›Elevated in infectious and inflammatory arthritis

›Serial trending supports diagnosis

›Joint aspiration

›WBC >50,000 cells/microL supports septic arthritis

›Gram stain and culture to guide antibiotic choice

›Crystal analysis for gout or pseudogout

Special circumstances

›Metabolic screen for healing optimization

›HbA1c in known or suspected diabetes

›Poor glycemic control impairs ligament healing

›Threshold >8.0% flags increased healing risk

›Vitamin D level when nutritional deficiency suspected

›Deficiency impairs bone and soft tissue healing

›Supplementation recommended if deficient

06Diagnostic Tests/dt82

Scoring Systems

›UCL injury grading system

›Grade I — sprain, ligament intact

›Microscopic tearing without macroscopic disruption

›Firm endpoint on stress test

›<15° laxity compared to contralateral

›Grade II — partial tear

›Macroscopic disruption, partial continuity maintained

›Firm endpoint present

›15-30° laxity

›Grade III — complete tear

›Complete disruption of proper UCL

›No firm endpoint

›>=30° laxity or >=15° more than contralateral

›Milner MRI Classification (treatment-oriented)

›Type 1 — partial or minimally displaced tear

›Immobilization appropriate

›Healing rate high with conservative management

›Type 2 — displacement <3 mm

›Immobilization may be appropriate

›Close imaging and clinical follow-up required

›Type 3 — displacement >3 mm

›90% fail immobilization

›Surgical consultation strongly recommended

›Type 4 — Stener lesion confirmed

›All require surgical repair

›Adductor aponeurosis interposition prevents healing

MRI

›Indications for MRI of thumb MCP

›Equivocal clinical examination

›Swelling limiting stress test reliability

›Borderline laxity without clear endpoint

›Pre-surgical planning

›Define displacement and Stener lesion presence

›Assess associated capsular and volar plate injury

›MRI performance characteristics

›UCL tear detection

›Sensitivity 99% for UCL tears (Rashidi et al., 2021)

›Specificity 100% for UCL tears

›Stener lesion detection

›Specificity 92% for displaced tears

›Gold standard imaging for surgical planning

›MRI protocol

›Dedicated hand coil preferred

›3 Tesla field strength optimal

›Coronal PD fat-saturated sequence primary

›Scout in three planes

›Axial sequences supplement Stener lesion identification

›Sagittal sequences assess volar plate

CT

›Indications for CT of thumb

›Complex bony injury assessment

›Comminuted avulsion fracture characterization

›Rolando fracture surgical planning

›When plain radiograph is equivocal

›Subtle intra-articular fracture lines

›CMC involvement assessment

›CT limitations

›Poor soft tissue contrast

›Cannot reliably characterize UCL itself

›Does not replace MRI for ligament assessment

›Radiation exposure consideration

›Reserve for definitive fracture characterization

›Not routine for pure ligament injuries

Ultrasound

›Point-of-care ultrasound for UCL

›Performance characteristics

›Sensitivity 96%, specificity 91% for UCL tears (pooled, Rashidi et al., 2021)

›Sensitivity 95%, specificity 94% specifically for Stener lesions (Qamhawi et al., 2021)

›Dynamic assessment capability

›Real-time valgus stress testing under ultrasound guidance

›Visualizes UCL displacement during stress

›Ultrasound technique

›High-frequency linear transducer — 15 MHz or higher

›Coronal plane over ulnar aspect of thumb MCP joint

›Normal UCL: fibrillar echogenic band from metacarpal head to proximal phalanx

›Stener lesion appearance

›Hypoechoic mass ("yo-yo on a string") proximal to adductor aponeurosis

›UCL stump visible superficial to hyperechoic aponeurosis

›Plain radiograph — first-line imaging

›Mandatory before stress testing

›AP, lateral, and oblique views of the thumb

›Rules out avulsion fracture, dislocation

›Stress radiographs

›Can quantify laxity objectively

›Less commonly used with availability of ultrasound and MRI

07Disposition/dispo35

Emergency department discharge

›Criteria for ED discharge

›Partial UCL tear confirmed (Grade I-II)

›Firm endpoint on valgus stress testing

›No displaced avulsion fracture on radiograph

›Thumb spica splint applied in ED

›MCP joint in slight flexion and neutral rotation

›IP joint free for active range of motion

›Hand surgery follow-up arranged within 1-2 weeks

›Earlier if any diagnostic uncertainty

›Earlier if worsening instability develops

Urgent hand surgery referral

›Indications for urgent outpatient hand surgery

›Complete UCL tear (Grade III)

›Absent endpoint, >=30° valgus laxity

›Surgery within 3-4 weeks of injury for best outcomes

›Stener lesion confirmed on ultrasound or MRI

›All confirmed Stener lesions require surgical repair

›Cannot heal with immobilization alone

›Displaced avulsion fracture

›Fragment displacement precludes ligament healing

›Surgical fixation required

›Referral timing

›Ideal surgery within 3 weeks of injury

›Inflammatory phase facilitates primary repair

›Delayed repair >6 weeks may require reconstruction

›1-2 week outpatient hand surgery appointment

›Advise patient not to delay if instability worsens

08Treatment/t82

Immediate ED management

›Immobilization

›Thumb spica splint application

›MCP joint at 15-20° flexion

›IP joint free

›Wrist in slight extension for comfort

›Splint materials

›Plaster or fiberglass moldable splint

›Pre-formed thumb spica splint acceptable for partial tears

›Hand surgery will transition to formal cast or operative plan

›Analgesia

›Acetaminophen 500-1000 mg orally every 6 hours as needed

›Maximum 4000 mg per 24 hours

›Reduce to 2000 mg per 24 hours in hepatic impairment

›NSAIDs — short course for acute pain

›Ibuprofen 400-600 mg orally every 6-8 hours with food

›Maximum 2400 mg per 24 hours

›Duration 5-7 days for acute musculoskeletal injury

›Opioids used sparingly if at all

›Short-course tramadol 50 mg orally every 6 hours if needed

›Avoid in elderly patients due to fall risk

Nonoperative treatment — partial tears

›Immobilization protocol for Grade I-II tears

›Thumb spica cast for 4-6 weeks

›MCP immobilized, IP joint free

›Fiberglass cast preferred for durability

›Controlled active range of motion

›IP joint active ROM exercises from day 1

›MCP ROM exercises starting at 3-4 weeks under supervision

›Transition to removable splint at 4-6 weeks

›Protective splinting continued through week 6

›Activity restriction until 12 weeks

›Return to activity milestones

›Sports return

›Partial tears: 6-12 weeks to full activity

›Protective taping or splinting for contact sports until 12 weeks

›Occupational return

›Light duties at 4-6 weeks

›Full manual labor at 10-12 weeks

›Occupational therapy referral

›Hand therapy for range of motion and strengthening program

›Scar management and edema control post-immobilization

Operative treatment — complete tears and Stener lesion

›Surgical indications

›Grade III complete UCL tear

›No endpoint on valgus stress testing

›>=30° laxity or >=15° more than contralateral

›Stener lesion — absolute surgical indication

›Adductor aponeurosis interposition prevents biological healing

›All confirmed Stener lesions require operative repair

›Displaced avulsion fracture

›Fragment too large to heal with immobilization

›ORIF with screw or suture anchor

›Surgical techniques

›Suture anchor reinsertion — most common technique

›UCL reattached to proximal phalanx base

›Excellent outcomes, no significant difference between anchor types

›Direct suture repair

›End-to-end repair for midsubstance tears

›Primary repair within 3 weeks optimal

›Suture tape augmentation

›Newer technique with promising short-term results

›Earlier return to function reported

›Ligament reconstruction with autograft

›Palmaris longus tendon graft for chronic insufficiency

›When primary repair not possible due to tissue quality

›Post-operative rehabilitation

›Thumb spica immobilization for 4 weeks post-op

›Followed by removable splint for additional 4 weeks

›Total immobilization 8 weeks

›Hand therapy initiation at 4-6 weeks

›Progressive ROM and strengthening

›Return to unrestricted use at 12 weeks

›Full strength recovery may take 3-6 months

Contraindications and precautions

›Absolute contraindications

›Corticosteroid injection into UCL region

›Risk of ligament weakening and rupture

›Not indicated for UCL injury management

›Relative precautions

›NSAIDs in renal impairment

›Use acetaminophen preferentially

›Adjust dose for eGFR <30 mL/min

›Casting in vascular compromise

›Ensure adequate circulation before applying circumferential cast

›Monitor for compartment syndrome

09Special Populations/sp72

Pregnancy

›Physiologic considerations

›Ligamentous laxity increased during pregnancy

›Relaxin-mediated ligamentous laxity may affect UCL baseline

›Contralateral comparison critical for accurate diagnosis

›Stress radiograph and advanced imaging

›Plain radiographs: use lead apron shielding

›MRI preferred over CT for advanced imaging — no ionizing radiation

›Ultrasound first-line advanced imaging in pregnancy

›Medication safety

›Acetaminophen preferred for analgesia

›Safe throughout pregnancy at standard doses

›Maximum 4000 mg per 24 hours

›NSAIDs contraindicated in third trimester

›Risk of premature ductus arteriosus closure

›Avoid from 28 weeks gestation onward

›Opioids use with caution

›Neonatal opioid withdrawal syndrome risk

›Limit duration and dose; involve obstetrics

›Operative timing

›Surgery generally deferred until after delivery if possible

›Anaesthetic risk to fetus in first trimester

›If urgent, second trimester considered safer

›Orthopedic and obstetric co-management required

Geriatric

›Injury pattern differences

›Higher prevalence of bony avulsion fractures in osteoporotic bone

›Bone weaker than ligament at insertion sites

›Assess bone mineral density if osteoporosis suspected

›Comorbidities affecting management

›Diabetes impairs soft tissue and bone healing

›Peripheral vascular disease reduces healing potential

›Medication adjustments

›Acetaminophen preferred analgesia

›Maximum 2000-3000 mg per 24 hours in frail elderly

›Hepatic metabolism reduced with aging

›NSAIDs use with caution

›Increased GI bleeding risk — add PPI if used

›Reduced renal function — monitor renal function if using

›Fall risk — avoid in patients with balance impairment

›Opioids higher risk in elderly

›Increased fall risk, delirium, constipation

›Avoid when possible; use lowest effective dose if required

›Rehabilitation considerations

›Prolonged immobilization increases stiffness and deconditioning

›Early IP joint ROM exercises essential

›Hand therapy referral at earliest safe opportunity

›Operative risk assessment

›Cardiopulmonary workup before elective surgery

›Frailty assessment to guide shared decision-making

Pediatrics

›Injury pattern differences in skeletally immature patients

›Physeal injury more common than ligament rupture

›Salter-Harris fractures at proximal phalanx physis

›Physis is the weak link in immature bone

›UCL tears in pediatric athletes do occur

›Increasing incidence with youth sport participation

›Same stress testing principles apply

›Imaging considerations

›Plain radiograph interpretation

›Open physes may mimic fracture lines

›Comparison radiograph of contralateral thumb helpful

›MRI preferred for soft tissue assessment

›No radiation, excellent physis and ligament visualization

›Sedation may be required in young children

›Treatment approach

›Physeal fractures — immobilization and close follow-up

›Most Salter-Harris I and II fractures heal with cast

›Salter-Harris III/IV require pediatric orthopedic consultation

›UCL tears in adolescents

›Same grading and treatment algorithm as adults

›Hand therapy milestones adjusted for growth plate status

›Return to sport

›Protective splinting mandatory for contact sports

›Return to sport after ligament healing confirmed clinically

10Background/b62

Epidemiology

›Incidence and prevalence

›Among the most common skiing injuries — estimated 50,000-200,000 cases per year in North America

›Accounts for 6-9% of all ski injuries

›Predominantly acute mechanism in contemporary practice

›Historically described in 1955 by Campbell in Scottish gamekeepers

›Chronic attritional injury from neck-breaking technique

›Contemporary usage refers to acute and chronic UCL injuries

›Demographics

›Affects all ages and both sexes

›Peak incidence in active adults aged 20-40 years

›Higher incidence in males due to contact sport participation

›Sport-specific risk

›Skiing: predominant modern cause of acute injury

›Ball sports: football, basketball, baseball second most common

Pathophysiology

›Anatomy of the thumb MCP joint

›UCL anatomy

›Proper UCL: primary stabilizer against valgus stress in flexion

›Accessory UCL: taut in extension, stabilizes volar plate

›Origin on metacarpal head, insertion on proximal phalanx base

›Adductor aponeurosis relationship

›Adductor pollicis aponeurosis lies superficial to UCL

›Acts as barrier to UCL displacement under normal anatomy

›Stener lesion mechanism

›Complete UCL rupture at distal insertion

›Proximal phalanx avulsed from UCL attachment

›Folded adductor aponeurosis interposes between UCL and its insertion

11Patient Discharge Instructions/pdi46

copy discharge instructions

›Diagnosis and explanation

›Gamekeeper's thumb or skier's thumb — injury to the ulnar collateral ligament of your thumb

›This ligament holds the thumb stable during pinching and gripping

›Partial tears heal well with immobilization; complete tears may need surgery

›Your treatment plan

›You have been given a thumb spica splint to protect your thumb

›Keep the splint on at all times unless instructed otherwise

›Splint care instructions

›Protect the splint

›Keep it dry — cover with a plastic bag for showering

›Do not modify or remove the splint unless hand surgery advises

›Finger movement

›Move your index, middle, ring, and little fingers freely

›Move your thumb tip (IP joint) gently unless told otherwise

›Pain management at home

›Acetaminophen (Tylenol) for pain

›500-1000 mg every 6 hours as needed

›Do not exceed 4000 mg in 24 hours

›Ibuprofen (Advil, Motrin) with food

›400 mg every 6-8 hours as needed

›Avoid if you have kidney problems, stomach ulcers, or are pregnant

›Ice for swelling

›15-20 minutes on, 20 minutes off

›Wrap ice in cloth — do not apply directly to skin

›Elevate your hand above heart level

›Reduces swelling in the first 48-72 hours

›Follow-up instructions

12References/r43

Guidelines and key sources

›Primary evidence sources

›Chang AL, Merkow DB, Bookman JS, Glickel SZ. Thumb MCP Joint UCL Injuries: Management and Biomechanical Evaluation. J Am Acad Orthop Surg. 2023

›PMID 36548149

›Comprehensive review of management and biomechanics

›Ritting AW, Baldwin PC, Rodner CM. UCL Injury of the Thumb MCP Joint. Clin J Sport Med. 2010

›PMID 20215892

›Mechanism, examination, and classification review

›Rhee PC, Jones DB, Kakar S. Management of Thumb MCP UCL Injuries. J Bone Joint Surg Am. 2012

›PMID 23138242

›Stress testing thresholds and surgical decision-making

›Imaging evidence

›Rashidi A et al. Evidence-Based Use of Clinical Exam, US, and MRI for UCL Tears. Eur Radiol. 2021

›PMID 33459856

›Systematic review and meta-analysis of imaging performance

›Qamhawi Z et al. Diagnostic Accuracy of US and MRI in Detecting Stener Lesions. J Hand Surg Eur. 2021

›PMID 33596684

›Meta-analysis: US sensitivity 95%, specificity 94% for Stener lesion

›Ebrahim FS et al. US Diagnosis of UCL Tears of the Thumb and Stener Lesions. Radiographics. 2006

›PMID 16844929

›Technique and pattern-based approach for ultrasound diagnosis

›Classification and outcomes

›Milner CS, Manon-Matos Y, Thirkannad SM. Gamekeeper's Thumb — Treatment-Oriented MRI Classification. J Hand Surg. 2015

›PMID 25300993

›Type 1-4 classification guiding operative versus nonoperative decisions

›Samora JB et al. Outcomes After Injury to Thumb UCL — Systematic Review. Clin J Sport Med. 2013

›PMID 23615487

›High patient satisfaction with surgical repair confirmed

Evidence & Review

Evidence & Review