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1

Anatomy of the extensor Mechanism

Extensor retinaculum: Prevents extensor tendon bowstringing at wrist

Juncturae tendinum: Extensor tendon interconnections in hand that may mask proximal tendon lacerations

Sagittal bands: Centralize the extensor mechanism and attach to the volar plate at the metacarpophalangeal (MCP) joint

Central slip: Terminal extensor digitorum communis tendon; inserts at the base of middle phalanx (P2) and aids in proximal interphalangeal (PIP) joint extension

Lateral bands: Common extensor and intrinsics converge to form terminal extensor tendon, which inserts on base of distal phalanx (P3) and extends distal interphalangeal (DIP) joint.

Transverse retinacular ligament: Prevents dorsal subluxation of lateral bands in PIP extension, while pulling lateral bands volarly in PIP flexion. Injury may result in swan neck deformity.

Triangular ligament: Prevents volar subluxation of lateral bands. Injury may result in boutonnière deformity.

Oblique retinacular ligament (ligament of Landsmeer): Helps link PIP and DIP joint extension

In PIP flexion is relaxed to allow DIP flexion

In PIP extension is tight to allow DIP extension

Grayson/Cleland ligaments: Fibrous skin and neurovascular stabilizers lying volar (Grayson) and dorsal (Cleland) to digital neurovascular bundles, respectively (mnemonic: Grayson is ground; Cleland is ceiling)

2

Review the extensor compartments of the wrist

3

Flexor tendon anatomy

4

Flexor Pulley Anatomy

Flexor digitorum profundus (FDP): Inserts at metadiaphyseal region of the distal phalanx (P3), flexes DIP joint, aids in PIP and MCP flexion

FDP tendons of the middle, ring, and small fingers have a common muscle belly in the forearm.

Index FDP often has a distinct muscle belly.

Flexor digitorum superficialis (FDS): Inserts at metadiaphyseal of the middle phalanx (P2), flexes the PIP joint, aids in MCP flexion

Small finger FDS: absent approximately 20% of the time

Campers chiasm: FDS splits at level of proximal phalanx (P1) to allow FDP to pass through it.

Flexor tendon sheath: Tunnel encompasses tendons distal to MCP joint, creating a closed system separate from surrounding structures.

Vascular supply: Both intrinsic (direct feeding vessels) and extrinsic (diffusion via synovial sheath to flexor tendons)

Pulleys: Each digital flexor tendon sheath has five annular pulleys (A1–A5) and three cruciate pulleys (C1–C3)

A2 and A4 pulleys critical to preventing flexor tendon bowstringing

A1 involved in trigger finger

Thumb: 2 or 3 annular pulleys (A1, A2, Av [annular variable]) and an oblique pulley in between that prevents bowstringing of flexor pollicis longus (FPL) tendon,

5

Contents of the Carpal Tunnel

Contains the median nerve and nine flexor tendons (FPL, four FDS, and four FDP tendons)

FPL tendon most radial structure in carpal tunnel

Long and ring FDS tendons are volar to index and small FDS.

Transverse carpal ligament (TCL): Roof of carpal tunnel

Ulnar tunnel (Guyon canal): Contains ulnar nerve and artery

Borders: Volar carpal ligament (roof) and TCL (floor)

6

Lumbrical Anatomy

The lumbrical muscles flex the metacarpophalangeal joint and extend the proximal interphalangeal joint.

 

Lumbrical muscles: Originate on radial aspect of FDP tendons, and pass volar to transverse metacarpal ligaments (TMLs) to insert on the radial lateral bands (extensor hood)

Function: IP joint extension, relaxation of extrinsic flexor system

Innervation: Radial two lumbricals (median n.), ulnar two lumbricals (ulnar n.)

Intrinsic tightness: Limited PIP flexion with MCP joints held in extension (intrinsics on stretch, extrinsics [extensor tendons] relaxed)

Extrinsic tightness: Limited PIP flexion with MCP joints held in flexion (extrinsics on stretch, intrinsics relaxed)

7

Sensory Patterns of the Hand

8

Nerve/muscle interactions in the hand

Median nerve: Innervates pronator teres, FDS, FCR, PL, radial two lumbricals (Fig. 7.8)

Anterior interosseous branch of median nerve (AIN): Innervates FPL, index and long FDPs (50% of the time), pronator quadratus

Palmar cutaneous branch of median nerve: Usually lies between PL and FCR at distal wrist flexion crease and can be injured during the modified FCR Henry approach in treating distal radius fractures

Recurrent motor branch of median nerve: Innervates abductor pollicis brevis (APB), opponens pollicis, and superficial head of flexor pollicis brevis (FPB)

Ulnar nerve: Innervates FCU, ring/small FDPs, long FDP (50% of the time), and ulnar two lumbricals (see Fig. 7.8)

Deep motor branch of ulnar nerve: Innervates dorsal and volar interossei, abductor digiti minimi (ADM), flexor digitorum minimi, palmaris brevis, and deep head of FPB

Martin-Gruber anastomoses: Interconnections between motor fibers of the median and ulnar nerves in the forearm

Incidence: 17% of people

Type 1 (most common of four variations): Motor branches from the median nerve to the ulnar nerve that innervate median intrinsic muscles is most common.

Riche-Cannieu anastomoses: Interconnections of motor fibers of the median and ulnar nerve within the palm

Radial nerve proper: Innervates lateral portion of brachialis (also musculocutaneous), triceps, anconeus, brachioradialis, and extensor carpi radialis longus (ECRL) (see Fig. 7.8)

Divisions: Superficial sensory branch (SBRN) and posterior interosseous nerve (PIN)

PIN: Innervates all remaining extensor muscles

Extensor carpi radialis brevis (ECRB): Variable innervation from either radial nerve proper or PIN

Terminal branch of PIN: Lies on the floor of fourth extensor compartment and is excised as part of a partial denervation procedure for wrist arthritis

9

Distal Radius Fracture Overview

Composite figure outlining various important pathologies in the wrist (described in clockwise order from top right [purple] box). • The distal radius fractures often follow specific fracture types involving the radial, ulnar, volar, and dorsal columns. There are a variety of surgical techniques to fix these fractures according to the fracture pattern. • The multiple types of carpal instability include carpal instability nondissociative (CIND), carpal instability dissociative (CID), and carpal instability complex (CIC). CID is one of the more commonly faced pathologies, including dorsal intercalated segment instability (DISI) involving the scapholunate (SL) ligament and extrinsic stabilizers, as well as volar intercalated instability (VISI) involving the lunotriquetral (LT) ligament and extrinsic stabilizers. SL pathology can progress to DISI and eventually to different stages of scapholunate advanced collapse (SLAC) arthritis. • The distal radioulnar joint (DRUJ) has multiple dynamic and static stabilizers. When it is injured, the ulna is able to translate (usually dorsally) with respect to the radius. DRUJ arthritis can happen as a result of trauma (e.g., prior associated fracture), recurrent instability, or either OA or inflammatory arthritis. • The triangular fibrocartilage complex (TFCC) is one of the most important DRUJ stabilizers. Multiple tear patterns may be seen; the Palmer classification being one of the most useful to describe them. A TFCC tear has the potential to destabilize the DRUJ. • There are three types of lunate morphology and two types of capitate morphology. These are important considerations in assessment and treatment of various carpal pathologies. For example, a type 1 (flat) capitate has been shown to be a better indication for proximal row carpectomy than a type 2 (round) or type 3 (V-shaped).

10

Distal Radius Acceptable Radiographic measurements

Radial height, volar tilt, and radial inclination: 11:12:22 rule

Radial height: Average 11 mm; less than 5 mm of shortening accepted

Radial inclination: Average 22 degrees (Fig. 7.10); less than 5-degree change accepted

11

Distal Radius Fracture Review

Most common fractures of the upper extremity (>300,000 per year) in the United States, with bimodal distribution

Young patients: High-energy trauma (e.g., motor vehicle accident, fall from height)

Elderly patients: Low-energy falls; most common upper extremity osteoporotic fracture

Anatomy

Distal radius articular surface: Biconcave, scaphoid, and lunate facets

Distal radioulnar joint (DRUJ): Articulation with ulna at sigmoid notch

Lister tubercle: Small dorsal prominence; landmark for dorsal approach to wrist; cause of attritional rupture of extensor pollicis longus (EPL) after a distal radius fracture

Metaphysis: Thin cortex, vulnerable to bending forces

Deforming force: Brachioradialis insertion on radial styloid

Normal wrist: Distal radius bears 80% of axial load

Clinical evaluation

Pain, swelling, and deformity at the wrist after trauma

Open injuries more common in young patients

Arm should be examined for concurrent anatomic snuffbox and ulnar-sided wrist tenderness.

Median and ulnar nerve function should be assessed.

Radiographic evaluation (posteroanterior, lateral, and oblique views)

Intra articular involvement (Fig. 7.9): Fracture pattern, gap, and step-off

Distal fragment angulation: Apex dorsal (Smith fracture), apex volar (Colles fracture)

Radial height, volar tilt, and radial inclination: 11:12:22 rule

Radial height: Average 11 mm; less than 5 mm of shortening accepted

Radial inclination: Average 22 degrees (Fig. 7.10); less than 5-degree change accepted

Volar tilt (lunate fossa inclination): Average 11 degrees; less than 10-degree dorsal angulation accepted

Additional considerations

Ulnar variance: Neutral (normal), positive, or negative; assessed with forearm in neutral rotation, and compared with contralateral side (Fig. 7.11)

DRUJ involvement: True lateral radiograph assessed for DRUJ alignment

Ligamentous injuries: scapholunate (SL), lunotriquetral (LT), or TFCC

Associated fractures: ulnar styloid, distal ulna, carpus

Chauffeur fracture: Isolated fracture of radial styloid that may be associated with SL ligament disruption

Radiocarpal dislocation or “inferior arc” injury: Purely ligamentous or associated with styloid fracture (radial and/or ulnar)

Highly unstable and difficult to reduce closed

Other imaging studies: CT for detail of complex intraarticular patterns; MRI for occult fracture, bone contusion, associated soft tissue injury

Classification

Common eponyms (Colles, Smith, Barton, Hutchinson) predate radiography

More than 10 other schemes exist (e.g., AO, Frykman, Fernandez, Melone, Mayo) but largely fail to help with prediction of treatment or prognosis.

Treatment

Goals: Maintain reduction until union, restore function, prevent symptomatic posttraumatic radiocarpal osteoarthrosis

Factors: Age, medical condition, activity demands, bone quality, fracture stability, associated injuries

Nonoperative: Immobilization ± closed reduction

Indications for immobilization: Extraarticular, minimally displaced fracture; functionally low-demand patient

Closed reduction indicated in displaced fracture with abnormal radiographic parameters, especially in functionally high-demand patient

Technique of closed reduction: Volar translation of lunate with traction and ulnar deviation.

Dorsal hematoma block with local anesthetic, finger traps

Re-creation of deformity, manipulation of distal fragment

Sugar-tong plaster splint with three-point mold

Aim: To hook volar cortex to try to prevent loss of reduction.

MCP and IP joints must be kept free for motion.

Loss of reduction correlates with increasing age.

Postreduction benchmarks (American Academy of Orthopaedic Surgeons guideline)

Radial shortening less than 5 mm

Dorsal articular tilt less than 5–10 degrees

Intraarticular step-off less than 2 mm

Immobilization for 6–8 weeks (no evidence to support any particular type)

Wrist and digit stiffness, muscle atrophy, and disuse osteopenia may result from prolonged immobilization.

Operative treatment

Closed reduction and percutaneous pinning (CRPP) (see Fig. 7.9)

Indications: Extraarticular fracture in younger patients without osteoporosis

Is less often used today with the advent of volar plating. Can be used as an isolated treatment or as an adjunct with external fixation.

Techniques: Kapandji intrafocal technique or arthroscopically assisted reduction

External fixation

Indications: Alone for unstable fractures with soft tissue compromise or in combination with percutaneous pin fixation or internal fixation techniques in highly unstable fractures

Articular alignment is difficult to restore.

Overdistraction may lead to increased risk of complex regional pain syndrome (CRPS).

Open reduction with internal fixation (ORIF)

Patients undergoing ORIF should be monitored for symptomatic hardware that may need to be removed to prevent tendon rupture.

Distraction or bridge plating

Indications: Alternative to external fixation in highly comminuted unstable fractures or elderly patients with severe osteoporosis. Allows weight bearing through injured extremity and so a consideration in a multiple-trauma patient.

Technique: Secured second or third metacarpal and radial shaft (Fig. 7.12)

Can be combined with volar plating

Disadvantage: Second procedure to remove plate at 8–12 weeks

Dorsal plating

Indications: Dorsally displaced fractures with dorsal bony defects

Technique: Approach between third and fourth extensor compartments

Enables direct visualization of articular reduction

Historical disadvantage: Extensor tendon irritation or rupture from prominent hardware

Volar plating

Indications (most common): volarly or dorsally displaced fractures, more than 2 mm articular displacement, metaphyseal comminution, combined distal radius and ulna fractures

Technique: Henry approach between FCR and radial artery or through floor of FCR tendon sheath

Articular reduction not directly visualized; relies on fluoroscopic guidance

Fixed-angle and variable-angle plates available

Plates placed at or proximal to watershed line (Fig. 7.13)

Repair of pronator quadratus: No clinical benefit

Can be combined with dorsal bone grafting for dorsal comminution

Flexor tendon most commonly injured with a plate placed distal to the watershed line is the FPL, followed by the FDP of the index finger.

Extensor tendon most commonly injured with a volar plate is the EPL, from use of a screw that is too long.

Fragment-specific techniques

Considerations: Low-profile constructs, technically challenging

Indications: May be best suited to certain intraarticular fracture patterns, including those with volar-ulnar (“critical corner”) fragment

Hook plate may capture volar-ulnar fragment with less chance of flexor tendon irritation than standard volar plate implant.

Intramedullary nailing

May have role in stable extraarticular patterns, but minimal data available

Arthroscopic reduction assistance

Aids in articular reduction

Ensures screws do not penetrate the radiocarpal joint

Additional technical considerations

Injectable bone substitutes: Calcium phosphate, coralline hydroxyapatite

Possible role in dorsal or metaphyseal comminution

Postoperative motion: Evidence does not support any advantage of early over later motion recovery after surgical fixation of distal radius.

Ulnar styloid fracture: Concurrent treatment of ulnar styloid fracture is not routinely necessary; it has no additional clinical benefit if the DRUJ is stable to clinical examination after the distal radius fracture has been stabilized.

Painful nonunion/DRUJ instability in small number of cases after radial fracture reduction (<10%)

Complications

Acute carpal tunnel syndrome: Characterized by progressive, evolving paresthesias and disproportionate pain; requires emergent median nerve decompression (carpal tunnel release)

Mild, vague, and nonprogressive sensory dysfunction is not indicative of acute carpal tunnel syndrome.

Ulnar nerve palsy: Possible after high-energy displaced distal radius fracture

EPL tendon rupture

Late complication due to sheath hematoma, attritional wear, and/or vascular insufficiency near the Lister tubercle

Presentation: Painless, acute loss of thumb extension; inability to lift thumb off table with palm

Treatment: Extensor indicis proprius (EIP)—EPL tendon transfer followed by PL intercalary autograft reconstruction. The EIP is the more ulnar of the two extensor tendons over the index finger MCP joint and has the most distal muscle belly of the fourth extensor compartment tendons at the wrist.

Nonunion: Uncommon complication

Asymptomatic malunion in a functionally low-demand patient does not require treatment

Ulnocarpal impaction: Can be treated with distal ulna resection (low-demand patient) or ulnar shortening osteotomy (high-demand patient).

Corrective radius osteotomy with ORIF and bone grafting may be indicated in functionally high-demand patients to prevent adaptive carpal instability and possible midcarpal arthritis (Fig. 7.14).

Wrist arthritis: Associated with residual intraarticular step-off, but often does not necessarily correlate with patient-reported symptoms.

Tendon injury: Reported after volar (flexor and extensor) and dorsal plating (extensor)

FPL: Tendon most commonly ruptured after volar plating; potentially due to improper plate placement distal to watershed zone

EPL: Extensor tendon most commonly injured; potentially due to drill-bit penetration or dorsally prominent screws

CRPS: Vitamin C in doses of at least 500 mg/day for 50 days, in patients with normal renal function, may decrease the incidence of CRPS in women older than 50 years who are treated for a distal radius fracture, although this issue is controversial because new evidence disputes early reports.

12

Review Scaphoid fractures

Most common carpal fractures, accounting for up to 15% of acute wrist injuries

Anatomy of scaphoid

Approximately 75% covered by articular cartilage

Blood supply

Main (proximal ¾) supply from dorsal branch of the radial artery enters at dorsal ridge just distal to waist and flows in retrograde fashion toward proximal pole.

Distal ¼: Superficial volar branches of radial artery enter at distal tubercle

Danger: Tenuous and retrograde vascular supply puts waist and proximal pole fractures at risk for nonunion and posttraumatic osteonecrosis.

Diagnosis

Mechanism: Forced hyperextension and radial deviation of the wrist

Presentation: Swelling, anatomic snuffbox/volar tubercle tenderness, limited wrist and/or thumb motion

Radiographs: Standard wrist radiographs; additional scaphoid view—approximately 30 degrees of wrist extension and 20 degrees of ulnar deviation—displays scaphoid in best profile

Radiographs initially nondiagnostic in more than 30% of cases

If normal radiographic findings and high clinical suspicion, arm should be immobilized and physical examination and radiographs should be repeated in 2 weeks, or MRI should be obtained immediately.

Advanced imaging: Bone scan, ultrasonography, CT, and MRI have all been used for earlier diagnosis.

All advanced imaging modalities are better for ruling out rather than ruling in a scaphoid fracture.

MRI has highest sensitivity, specificity, and accuracy (all >95%) with high positive and negative predictive values at less than 24 hours.

Missed fracture: Failure of identification and immobilization for more than 4 weeks after fracture increases nonunion rate almost tenfold.

Classification

Locations (Fig. 7.15)

Tubercle, distal pole, waist (most common), proximal pole

Distal pole is most common in skeletally immature patients

Stability

Stable fractures: Transverse pattern, minimal comminution, and limited displacement

Unstable fractures: Vertical or oblique patterns, significant comminution, and wide displacement

CT: Required for determining displacement and stability

Treatment

Nonoperative

Cast immobilization for nondisplaced fractures

No difference in the type of cast for union, with similar outcomes seen in long-arm vs. short-arm and standard vs. additional thumb spica component

Time to union: Increases as the fracture location becomes more proximal.

Consequently, length of cast immobilization should be greater for more proximal fractures.

CT is best modality to assess union rates after treatment.

Operative

Indications: proximal pole fracture, more than 1 mm displacement, intrascaphoid angle more than 35 degrees (humpback deformity), comminuted or vertical/oblique fracture, and transscaphoid perilunate dislocation

Faster time to union and return to work in nondisplaced waist fractures with operative than with nonoperative management

Minimally displaced fractures: May be treated with percutaneous internal fixation using a headless compression screw

Displaced fractures: Formal ORIF via dorsal or volar approach

Most critical technical factor: Guide-pin placement should be within the central axes of both the proximal and distal fragments.

Approach: Volar and dorsal approaches have equivalent outcomes. In general, the dorsal approach is used for proximal pole fractures and the volar approach for distal pole injuries.

Outcomes: Union rates of more than 90% expected with surgical treatment

CT confirmation of union necessary before physical therapy is begun

Complications

Nonunion: Diagnosed on CT

Symptomatic early-stage scaphoid nonunion may be treated with ORIF and bone grafting (using distal radius or iliac crest) (Fig. 7.16).

Vascularized proximal pole: Inlay (Russe) technique used in cases with minimal deformity

Best diagnosed with presence of intraoperative punctate bleeding

Humpback deformity: Requires open-wedge interposition structural graft to restore scaphoid length and carpal alignment

Vascularized bone grafting has a role in nonunion with an avascular proximal pole.

Bone most commonly harvested from dorsal aspect of distal radius, based on 1,2 intercompartmental supraretinacular artery (1,2 ICSRA)

For correction of both humpback deformity and avascular proximal pole: Free transfer of medial femoral condyle bone graft, supplied by descending medial genicular, and connected end-to-side to radial artery

Scaphoid nonunion advanced collapse (SNAC) wrist: Untreated, chronic scaphoid nonunion may lead to characteristic progression of posttraumatic osteoarthrosis

Stage I—radioscaphoid arthritis

Stage II—involvement of the scaphocapitate joint

Stage III—involvement of the lunocapitate joint

Options for treatment of SNAC wrist include radial styloidectomy, distal scaphoid resection (Malerich procedure), proximal row carpectomy (PRC), scaphoid excision and four-corner (bone) fusion, and total wrist fusion, depending on stage of presentation and surgeon preference (Figs. 7.17 and 7.18).

13

DISI

carpal instability

DISI: Most common form of carpal instability; lunate and triquetrum tilt dorsally (see Fig. 7.9)

Etiology: SL ligament disruption

Dorsal fibers are stronger than volar fibers.

DISI develops after secondary injury to stabilizing dorsal and/or volar extrinsic ligaments, volar scaphotrapeziotrapezoid (STT) ligaments

Mechanism: Scaphoid hyperflexion and lunate hyperextension

May be traumatic or may result from inflammatory or crystalline arthropathy

Physical examination: Dorsal wrist pain with loading, diminished grip strength

Watson shift test: Reproduction of pain/palpable clunk with scaphoid shift test (dorsally directed pressure over volar scaphoid tubercle while wrist is brought from ulnar to radial deviation subluxates or dislocates scaphoid over dorsal ridge of distal radius that, when released, causes scaphoid to reduce with painful clunk)

Bilateral nonpainful clunks constitute a negative test result.

Diagnosis

Radiographs: Cortical ring sign showing flexion of the scaphoid, increased scapholunate angle (>70 degrees), or widened scapholunate interval (>3 mm).

Pencil test or bilateral clenched-fist (AP grip) comparison views: Dynamic DISI with relatively widened scapholunate interval on affected side (stress radiographs)

MRI: Best but not perfect for detection of SL ligament injury

Wrist arthroscopy: Gold standard to diagnose any wrist ligament injury (including SL)

Geissler classification (Table 7.2)

Treatment: Depends on stage of instability

Partial ligament injuries (predynamic or dynamic instability): Nonoperative treatment or arthroscopic débridement.

For acute SL ligament rupture: Rarely amenable to primary repair alone

After delayed diagnosis of SL ligament rupture: Open reduction of scapholunate interval and K-wire pinning with or without dorsal capsulodesis or tendon autograft reconstruction

Various tendon (e.g., Brunelli) and bone-retinaculum-bone grafts have also been attempted for SL reconstruction.

Limited clinical data on reduction-association of scaphoid and lunate (RASL) procedure or other forms of implants to span SL joint

Scapholunate advanced collapse (SLAC): Chronic untreated static SL instability

Fig. 7.23 illustrates the three stages.

Radiolunate joint is often spared.

Treatment: Depends on condition of articular surfaces and competency of the radioscaphocapitate ligament.

Options include radial styloidectomy, PRC, scaphoid excision with four-corner arthrodesis, isolated capitolunate arthrodesis, and total wrist arthrodesis.

Partial wrist denervation: Excision of the terminal branch of the PIN ± AIN is often done in conjunction with these procedures but is also an option on its own.

14

Review VISI, and other less common 

carpal instability

Second most common form of carpal instability; lunate and scaphoid tilt volarly (see Fig. 7.9)

Disruption of LT interosseous ligament

Volar fibers are stronger than dorsal fibers.

Static instability: Accompanying injury of the dorsal extrinsic ligaments (dorsal radiocarpal and intercarpal ligaments)

Physical examination

Ulnar-sided wrist pain

Lunotriquetral shear or shuck test

Diagnosis

Radiographic findings: Break in Gilula arc on posteroanterior view and scapholunate angle decreased to less than 30 degrees on lateral view

MRI may show pathology of LT ligament.

Wrist arthroscopy: Gold standard

Treatment

Direct volar lunotriquetral ligament repair

FCU tendon augmentation

Lunotriquetral arthrodesis

Ulnar shortening osteotomy for patients with concurrent ulnocarpal impaction syndrome

Midcarpal carpal instability nondissociative (CIND)

Clunking wrist that may or may not be painful

Many patients have generalized ligamentous laxity.

History of trauma often absent

Sudden shift of proximal carpal row with active ulnar deviation

Nonoperative management, including hand therapy and proprioceptive training, should be maximized.

Midcarpal fusion preferred over soft tissue reconstructions in patients in whom non-operative treatment fails, because the latter repair may stretch out.

Radiocarpal dislocation (CIND)

Rare, high-energy injury

“Inferior arc” injury

May be associated with intracarpal injury, acute carpal tunnel syndrome, possible compartment syndrome, other major musculoskeletal and/or organ injuries

May be purely ligamentous or include radial and/or ulnar styloid fractures

Ulnar translocation of the carpus signifies global ligamentous disruption.

The affected ligaments are:

Volar extrinsic ligaments (in order, radial to ulnar): Radioscaphocapitate, long radiolunate, short radiolunate, and radioscapholunate (also termed ligament of Testut—vestigial neurovascular contents)

Ulnocarpal ligaments: Ulnolunate, ulnotriquetral, and ulnocapitate

ORIF of radial styloid fractures may reduce ulnar translocation of the carpus by restoring radioscaphocapitate ligament stability.

May also require direct ligamentous repair and/or external fixation or bridge plate to neutralize forces

Associated intracarpal injuries treated simultaneously

Carpal instability adaptive from distal radius malunion

May result from deformities with more than 30 degrees of dorsal angulation in the sagittal plane

Concern for midcarpal pain/arthritis

Treated with corrective osteotomy of the distal radius

Perilunate dislocations (carpal instability complex)

Potentially devastating injuries resulting from forced dorsiflexion, ulnar deviation, and intercarpal supination

Approximately 25% of cases may be missed in the emergency department due to poor radiographs and lack of awareness. Key is to analyze the three Gilula lines on an AP plain radiograph.

Mayfield described four stages of perilunar disruption of ligamentous constraints, proceeding in counterclockwise direction

Stage I: Scapholunate disruption

Stage II: Capitolunate disruption

Stage III:

Lunotriquetral disruption

Dorsal midcarpal dislocation

Capitate appears dorsal to lunate on lateral view

Stage IV:

Circumferential disruption

Volar lunate dislocation: Osteonecrosis of the lunate avoided because of attached volar extrinsic (short radiolunate) ligament that maintains blood supply (Fig. 7.24)

Lesser-arc injuries: Purely ligamentous

Greater-arc injuries: Carpal fracture (transscaphoid most common)

Treatment: Prompt attempt at closed reduction, especially in setting of acute carpal tunnel syndrome

Stable closed reduction may allow for delayed definitive surgical management, but there is no role for closed treatment alone.

Irreducible injuries necessitate urgent operative intervention.

ORIF may require dorsal and/or volar approach.

Combination of ligamentous repair, fracture fixation, dorsal capsulodesis, and K-wire pinning of proximal row and midcarpal joint (Fig. 7.25)

Carpal tunnel release for associated acute carpal tunnel syndrome

Cast immobilization for 2–3 months

Late diagnosis leads to consistently poor outcomes

Methods of treating delayed and chronic perilunate dislocations are controversial.

15

what are the volar extrinsic ligaments in order?

Volar extrinsic ligaments (in order, radial to ulnar): Radioscaphocapitate, long radiolunate, short radiolunate, and radioscapholunate (also termed ligament of Testut—vestigial neurovascular contents)

16

Review metacarpal shaft fractures

Transverse, oblique, or spiral

Higher risk of malrotation: 5 degrees of malrotation results in 1.5 cm of digital overlap.

Acceptable angulation/shortening of each metacarpal shaft

Index/long: less than 10 degrees

Ring/small: less than 30 degrees

All: less than 5 mm of shortening is acceptable without significant functional deficit.

Every 2 mm of metacarpal shortening leads to 7 degrees of extensor lag.

Irreducible displaced fractures: CRPP or ORIF

Intramedullary pinning: Antegrade or retrograde

Lag screw fixation: Fracture length twice the bone diameter

Dorsal plates: Prominent dorsal plates irritate or injure extensor tendons.

Multiple metacarpal shaft fractures are unstable injuries that often necessitate surgical intervention.

17

Review metacarpal head and neck fractures

Most commonly occurs in the index or middle finger

Some condylar injuries represent ligamentous avulsions

Surgical treatment

More than 1 mm of articular step-off: ORIF

Open fight bites: Early surgical débridement and assessment of extensor mechanism injury

Severe open or comminuted fractures (e.g., gunshot wounds): Spanning external fixation.

Severe comminuted closed fractures: Arthroplasty or arthrodesis (especially index MCP)

Joint stiffness: most common complication with both nonoperative and operative treatment.

Metacarpal neck fracture

Weakest portion of metacarpal

Most frequently involves the ring and small fingers

Boxer’s fracture: Metacarpal neck fracture of the small finger

Deforming forces: Intrinsic muscles lead to apex dorsal angulation.

Examiner should check for malrotation, pseudoclawing, and MCP joint extensor lag.

Nonoperative treatment: Most cases can be treated with closed reduction (dorsal pressure or Jahss maneuver) and 3–4 weeks of immobilization.

Acceptable angulation of each metacarpal neck

Index/long: less than 15–20 degrees

Ring: less than 30–40 degrees

Small: less than 60–70 degrees (controversial)

Greater compensation from more mobile fourth and fifth carpometacarpal (CMC) joints

Irreducible fractures: CRPP (antegrade, retrograde, or transverse)

18

Metacarpal base fractures

 

including thumb

Metacarpal base fracture and CMC joint dislocation

Stable, minimally displaced fractures of metacarpal base are treated nonoperatively.

Ring and small CMC joint fracture-dislocations often result from higher-energy mechanisms.

Radiographs: Pronated 30-degree oblique view

CT: For complex injuries

Small-finger CMC joint fracture-dislocation is termed a reverse or baby Bennett fracture.

Extensor carpi ulnaris (ECU) tendon is major deforming force.

Accompanying distal row carpal fractures may be seen, especially of the hamate and capitate, which can signify high-energy mechanism.

Closed reduction may be attempted, but these are unstable injuries that often require surgical stabilization via CRPP or ORIF. Over the fourth and fifth CMC joints, care must be taken not to injure the dorsal sensory branch of the ulnar nerve during open approaches.

Delayed treatment, painful malunion, or posttraumatic osteoarthrosis may require arthrodesis.

Thumb metacarpal fracture

Most common pattern is extraarticular basilar fracture.

Acceptable angulation: Up to 30 degrees, secondary to compensatory CMC joint motion

Excessive angulation: MCP joint hyperextension, requiring CRPP or ORIF

Mnemonic for reduction maneuver is TAPE: traction, abduction, pronation, and extension of thumb metacarpal (©Kakar).

Bennett fracture: Intraarticular fracture-dislocation (Fig. 7.26)

Deforming forces: Abductor pollicis longus (APL) and thumb extensors cause proximal, dorsal, and radial displacement of the metacarpal shaft.

APL causes supination and adduction of the metacarpal shaft.

Anterior oblique or “beak” ligament keeps the volar-ulnar base fragment reduced to the trapezium.

Treatment: CRPP or ORIF based on the size of fragment

Reduction: Traction, palmar abduction, and pronation

Goal: More than 1–2 mm of articular step-off

Rolando fracture: Comminuted intraarticular fracture (T or Y shape) (Fig. 7.27)

19

Review GameKeeper's Thumb

Injuries: Acute (skier’s thumb) or chronic (gamekeeper’s thumb) injury to the ulnar collateral ligament (UCL) of the thumb via supination of the proximal phalanx around intact RCL

UCL function is critical for strong, effective pinch.

Mechanism of injury: Forceful thumb hyperextension and/or hyperabduction

Spectrum of injury: Dorsal-to-volar, involving proper UCL, accessory UCL, and volar plate. Ligament injury tends to occur at its insertion at the base of the proximal phalanx.

Radiographs: Obtained prior to stress examination to rule out bony avulsion injury.

MCP stress test (in the absence of fracture): MCP joint is stressed with radial deviation both in neutral and in 30 degrees of flexion.

Instability in 30 degrees of flexion: Proper UCL and/or dorsal capsule injury

Instability in neutral: Accessory UCL and/or volar plate injury

Threshold: More than 35 degrees of opening or more than 20 degrees of difference from opening of uninjured thumb

Complete vs. partial tears: Difficult to differentiate by physical examination alone

Diagnosis: Stress radiographs and/or MRI

Partial injuries: Treated with thumb spica cast immobilization for 4–6 weeks.

Stener lesion: Occurs in 85% of complete injuries when the adductor pollicis aponeurosis is interposed between the avulsed UCL and its insertion site on the base of the proximal phalanx (Fig. 7.28)

Treatment: Surgical reattachment of ligament through drill holes, suture anchor, or interference screw.

Large displaced avulsion fracture of the base of the proximal phalanx: Requires ORIF

Chronic UCL injuries: Ligament reconstruction with either adjacent joint capsule or tendon graft, ± pinning of joint.

Posttraumatic osteoarthrosis: MCP arthrodesis

Radial collateral ligament (RCL) injury: RCL instability is due to overpull of adductor, which causes proximal phalanx to pronate around intact RCL. It is much more rare than the UCL tears, but has a similar evaluation and treatment approach.

Isolated injuries to the thumb MCP radial collateral ligament: After a forced flexion-ulnar deviation mechanism

Nonoperative treatment in most cases

Surgery: For high-grade or complete tears associated with volar MCP subluxation. Ligament injury tends to occur at its origin at the metacarpal.

20

What is Kaplan's lesion?

An irreducible dorsal MCP joint dislocation with volar plate interposition

21

how do you treat simple PIP joint dislocations after reductions?

simple buddy taping

22

Finger Fracture/Dislocations

Dorsal dislocation accompanied by fracture at P2 base (Fig. 7.29)

Hastings classification based on amount of P2 articular surface involved (Table 7.3)

Treatment

Dorsal block splinting, dorsal block pinning, ORIF, or hemihamate reconstruction

More than 30% of involvement of the base of the proximal phalanx tends to lead to persistent dorsal subluxation of the PIP joint; surgical reconstructions such as volar plate arthroplasty and hemihamate transfer aim at restoring the volar buttress to dorsal displacement.

Maintenance of adequate joint reduction is most important factor for favorable long-term outcome.

Chronic PIP fracture-dislocations without severe posttraumatic osteoarthrosis: Hemihamate reconstruction or volar plate arthroplasty, depending on functional demands of the patient.

PIP posttraumatic arthritis: Silicone arthroplasty or arthrodesis

Highly comminuted pilon fractures are best handled with dynamic distraction external fixation for simple ligamentotaxis and early ROM.

DIP dislocation and distal phalanx fractures

Reducible DIP dislocation: Closed reduction and immobilization in slight flexion with a dorsal splint for 2 weeks

Irreducible DIP dislocation: Caused by interposition of the volar plate

Treatment: Open reduction and extraction of the volar plate

Stable tuft fracture (common): No specific treatment apart from temporary splinting

Open injuries: Irrigation and débridement, reduction, nail bed repair (if necessary), antibiotics, tetanus prophylaxis, and splinting

Unstable displaced fractures of the distal phalanx: Percutaneous pinning to support the nail bed repair

Common associated injuries: Soft tissue and/or nail bed disruption

Highly comminuted injuries with significant soft tissue loss: Revision amputation (shortening and closure)

Seymour fracture: A transverse physeal injury that may become displaced and require extraction of interposed nail matrix to prevent malunion. This is considered an open fracture.

For further details see the section Nail and Fingertip Injuries.

23

Extensor Tendon Injuries

Zone I injury (mallet finger)

Location: Terminal extensor tendon at or distal to DIP joint

Mechanism: Sudden forced flexion of the extended fingertip

Presentation: Patient cannot actively extend at DIP joint, and finger remains in flexed posture.

Bony mallet: Bony avulsion injury from dorsal base of P3 (bony mallet)

Nonoperative treatment: If detected less than 12 weeks of injury

DIP joint extension splinting for 6 weeks, followed by part-time splinting for an additional 4–6 weeks

No proven best type of splint

Hyperextension should be avoided because it can cause skin necrosis.

Maintenance of PIP joint motion often overlooked

Nondisplaced bony mallet finger: Extension splinting until fracture union

Displaced bony mallet finger: Controversial surgical indication

Treatment options: CRPP through DIP joint or extension block pinning if there is joint subluxation on the lateral radiograph or >50% articular surface

Chronic mallet finger (>12 weeks after injury)

Closed treatment: If joint supple, congruent, and without arthritic changes

Dynamic splinting + serial casting: Contracted joint

Operative treatment: Tenodermodesis, Fowler tenotomy

Prolonged DIP flexion: Associated with swan neck deformity from dorsal subluxation of lateral bands and corresponding PIP joint hyperextension

Supple swan neck deformities may be treated with

Fowler central slip tenotomy (maximum deformity 35 degrees), which allows the extensor apparatus to slide proximally, thereby increasing its effective pull at the DIP joint.

Boutonnière deformity is prevented by not injuring the triangular ligament, thereby keeping the lateral bands dorsal of the midline in the sagittal plane.

Spiral oblique retinacular ligament (SORL) reconstruction

DIP joint arthrosis: DIP arthrodesis.

Zone II injury

Location: Middle phalanx of digit or over proximal phalanx of thumb

Mechanism: Dorsal laceration or crush component

Partial disruptions (<50%): Local wound care and early mobilization

Lacerations more than 50%: Direct surgical repair

Controversial: Temporary pinning across terminal joint after direct repair

Zone III injury (boutonnière)

Location: PIP joint of digit (central slip) or MCP joint of thumb

Open injuries: Directly repaired if possible

Loss of tendon substance: Free tendon graft or extensor mechanism turndown flap

Elson test: Examiner performs by flexing the patient’s PIP joint 90 degrees over the edge of a table and asking patient to extend the PIP joint against resistance.

Central slip intact: The DIP joint will remain supple as the power of extension is focused at the central slip insertion with the lateral bands remaining lax.

Central slip rupture: The DIP joint will be rigid as the power of extension is diverted to the lateral band rather than the central slip.

Acute boutonnière deformity: Results from central slip disruption and volar subluxation of the lateral bands, resulting in DIP hyperextension (Fig. 7.31)

Closed injury: Full-time PIP extension splinting for at least 6 weeks, followed by part-time splinting for an additional 4–6 weeks.

DIP flexion maintained to balance extensor mechanism by encouraging the lateral bands to drift dorsal of the midline in the sagittal plane.

Chronic (untreated) boutonnière deformity

May require dynamic splinting or serial casting to achieve maximal passive motion first

Terminal extensor tenotomy, PIP volar plate release

Central slip reconstruction techniques: Tendon graft, extensor turndown, lateral band mobilization with transverse retinacular ligament release

PIP joint arthrosis: PIP arthrodesis

Zone IV injury

Location: Proximal phalanx of digit or over the metacarpal of thumb

Treatment: Similar to that for injuries in zone II

Common complication: Adhesion formation leading to loss of digital flexion

Prevention of adhesion formation: Early protected ROM and dynamic splinting

Failure of nonoperative management may require extensor tenolysis.

Zone V injury

Location: MCP joint of digit or over CMC joint of thumb

Treatment (most): Early mobilization and dynamic splinting

Fight bite: Surgical débridement of the MCP joint with loose or delayed wound closure

Most common organism: Eikenella corrodens

Extensor lag and loss of flexion are common.

Sagittal band rupture (flea-flicker injury): From forced extension of flexed digit

Long finger most commonly injured

Rupture of the stronger radial fibers may lead to extensor tendon ulnar subluxation/dislocation.

Finger will be held in flexed position at MCP joint with no active extension.

Passive extension of the MCP joint is possible, and the patient can then usually maintain the finger in an extended position.

Treatment

Acute injuries: 4–6 weeks of extension splinting of the MCP joint (one of the only exceptions to splinting the MCP joints in flexion).

Failure of nonoperative management or missed injuries: Repair or reconstruction of the sagittal band

Zone VI injury

Location: Metacarpal and represents most frequently injured zone

Associated injuries: Lacerations of superficial veins and nerves

Laceration more than 50% tendon: Direct surgical repair

Early protected motion advocated postoperatively

Dynamic splinting may offer better short-term ROM and strength, without increased complications, than static splinting.

Good prognosis is good in the absence of concurrent bony injury.

Zone VII and VIII injuries

Location: Level of the wrist joint (VII) and distal forearm at the musculotendinous junction (VIII)

Lacerations at wrist level are usually associated with extensor retinaculum disruption, and postoperative adhesions are common.

Treatment

The retinaculum should be repaired to prevent tendon bowstringing.

Static immobilization with the wrist held in extension and the MCP joints partially flexed for the first 3 weeks, followed by protected motion

The results of surgical repair in these zones are not as good as those in zones IV, V, and VI.

24

Review the pathoanatomy of a boutinear's deformity:

 

Elson's test

Pathomechanics of the boutonnière deformity. (A) Attenuation of the central slip results in unopposed flexion at the PIP joint. (B) With PIP joint flexion, the lateral bands drift volar to the axis of rotation at the PIP joint. The lateral bands stay in the volar position owing to loss of dorsal support from the attenuated triangular ligament and contracture of the transverse retinacular ligament.

25

Flexor tendon injury

Overview

Concomitant neurovascular injury is common when associated with lacerations.

Physical examination: Examiner should note the resting posture of the hand and check the tenodesis effect with passive wrist flexion and extension.

Each digit should be tested in isolation for active DIP (FDP function) and PIP flexion (FDS function).

Treatment

Partial lacerations may be associated with gap formation or triggering with nonoperative treatment

Triggering treatment: Trimming tendon ends or performing epitendinous repair

Lacerations more than 60% tendon width: Simultaneous core and epitendinous repair within 3 weeks (ideally <10 days of injury)

Basic surgical techniques of flexor tendon repair

Strength of repair proportional to number of suture strands that cross repair site (core sutures)

6–8 strands have superior strength and stiffness

High-caliber (e.g., 5-0 instead of 6-0) suture material decreases gap formation and increases strength and stiffness.

A locking-loop configuration decreases gap formation.

Epitendinous repair decreases gap size and increases overall strength by 10%–50%.

Purchase, defined as the longitudinal distance from cut tendon end to transverse component of the core suture, should be 0.7–1.2 cm.

Dorsally placed core sutures are stronger.

Repair of the flexor tendon sheath has no effect on flexor tendon repair.

Atraumatic, minimal-touch technique minimizes adhesions.

A2 (most important) and A4 pulleys (oblique pulley in thumb) must be preserved to prevent bowstringing.

Risk of tendon rupture greatest 3 weeks after repair; failure typically occurs at suture knots.

Wide awake local anesthesia no tourniquet [WALANT] (uses lidocaine withepinephrine) allows one to perform flexor tendon repair with the patient wide awake to allow testing of the integrity of the repair.

Early protected ROM is thought to increase tendon excursion, decrease adhesion formation, and increase repair strength.

Postoperative use of an active flexion protocol requires a minimum four-strand repair with epitendinous suture.

Young children cannot comply with protected motion protocols so require cast immobilization for 4 weeks.

Tendon healing factors

Intrinsic healing is directed by tendon fibroblasts (tenocytes)

Extrinsic healing potential is limited

Only small contribution from repair cells within tendon sheath or from vascular invasion

Tendon healing is strongly influenced by biomechanical stimuli, and early mobilization has been shown to decrease adhesion formation and increase the strength of repair tissue.

No definitive evidence of growth factor or stem cell augmentation of healing

Treatment according to Verdan zones (Fig. 7.32)

Zone I injury (rugger jersey finger)

Location: FDP avulsion distal to the FDS insertion

Tendons involved: FDP only

Mechanism: Forced extension of the DIP joint during grasping

The ring finger is involved in 75% of cases.

Classification: Leddy and Packer (Fig. 7.33)

Type I: FDP is retracted to the palm; requires direct repair within 7–10 days.

Type II: May be directly repaired up to 6 weeks later because the intact vincula prevent FDP retraction proximal to the PIP joint

Type III: Associated with small bony avulsion fragment with minimal retraction as the fragment is caught upon the pulley; may be successfully repaired up to 6 weeks after injury

Type IV: FDP is avulsed off bony fragment and as such can retract proximally and requires expeditious repair (rare subtype).

Key point: Profundus advancement of 1 cm or more carries a risk of DIP joint flexion contracture or quadrigia.

Quadrigia: FDP tendons (middle, ring, small) have a common muscle belly, so distal advancement of one tendon compromises flexion of the adjacent digits, because the advanced FDP tendon has greater tension in comparison with the laxity of the adjacent FDP tendons. As such, when the advanced FDP tendon contracts, the efficiency of contraction of the adjacent FDPs is decreased, resulting in decreased DIP joint motion of the adjacent digits.

Full PIP flexion in chronic injuries: Treated with observation or DIP arthrodesis in a functional position

Intact FDS function should never be sacrificed to permit reconstruction of an injured FDP tendon.

Two-stage flexor tendon reconstruction with silicone rod can be considered in young motivated patients, although the results can be unpredictable.

Zone II (“no man’s land”) injury

Location: Between the FDS insertion and the distal palmar crease within flexor tendon sheath

Tendons involved: Both the FDS and FDP may be injured.

Key point: Tendon lacerations may be at a different level from that of the skin laceration, depending on the position of the finger when the laceration occurred.

Treatment: Direct repair of both tendons with a core and epitendinous suture technique followed by an early mobilization protocol

Outcomes: Historically poor owing to the high rate of adhesion formation at the pulleys and associated digital neurovascular injuries

Although advances in postoperative rehabilitation have improved the clinical outcomes, up to 50% of patients require subsequent tenolysis to enhance active motion at least 3 months after repair.

Zone III injury

Location: Occurs between the distal palmar crease and the distal end of the carpal tunnel

Tendons involved: Both FDP and FDS can be injured.

Treatment: In comparison with results of zone II injuries, those of direct repair are much better owing to a lack of the pulley system and hence fewer adhesions.

Key point: Lumbrical muscles originate from the radial aspect of FDP tendons in zone III.

Zone IV injury

Location: Within the carpal tunnel

Zone V injury

Location: Between proximal carpal tunnel and musculotendinous junction

Treatment: Direct repair in this zone has a favorable prognosis.

Outcomes: Results may be compromised by coexisting nerve injury.

FPL injury

Zone I injuries: Distal to IP joint

Zone II injuries: Between IP and MCP joints

Zone III injuries: Deep to thenar muscles

Postoperative rehabilitation

Two most common rehabilitation protocols are those of Kleinert and Duran.

Kleinert protocol: Dynamic splinting, allowing for active digit extension and passive digit flexion

Duran protocol: Other hand used to perform passive digital flexion exercises

Requires strict patient compliance

Both protocols: Avoidance of active flexion for 6 weeks

Newer advancements: Components of early active digital flexion added to reduce adhesion formation and increase tendon excursion

These protocols require stronger repair methods (i.e., use of a minimum of four core sutures).

Flexor tendon reconstruction

Indication: Failed primary repair or chronic, untreated injuries

Requirements: Supple skin, a sensate digit, adequate vascularity, and full passive ROM of adjacent joints

The majority of cases require two-stage reconstruction.

Stage I: Implantation of a temporary silicone (Hunter) rod that is secured distally but allowed to glide proximally to recreate a “tunnel” for the new tendon to glide through

A2 and A4 pulleys preserved or reconstructed

Stage II: Performed more than 3 months later, once full passive ROM has been attained and a sheath has formed around the silicone rod.

Rod is removed and tendon autograft is passed through the sheath

Grafts

Extrasynovial (e.g., palmaris longus or plantaris): Act as scaffold to allow tenocytes infiltration and collagen deposition

Intrasynovial (e.g., FDS): Retain their gliding surface and heal intrinsically

Postoperative rehabilitation: Despite the need for an intensive program, subsequent tenolysis is often required (>50%).

26

Trigger finger classification

27

Stress test of the the thumb UCL 

 

gamekeepers/skier thumb

Instability in Neutral--Accessory UCL and or volar plate 

Instability at 30 degrees--Proper UCL and or dorsal capsular injury

 

Threshold--more than 35 degrees of opening, or 20 degrees compared to the other side

28

Extensor Tendon Pearls

less than 50% or active extensionneeds no repair and are treated with early protected motion

Zone 1 = Mallet finger

Zone 3 = Boutonniere

Zone 5 = Fight bite or saggital band rupture

Zone 7 = extensor retinaculum disruption

29

Flexor tendon injury overview

30

Flexor tendon Zone 1 Injuries

 

Jersey Finger

Profudus advancement of 1cm or more carries a risk of DIP joint flexion contracture or quadrigia

Type 1 requires repair within 7-10 days 

Type 2 can be repaired wihtin 6 weeks due to vinicular blood supply

Type 3 bony avulsion--direct repair within 6 weeks