Finger dislocation

1. High-Yield Summary

• The “Coach’s Finger” Paradox: The proximal interphalangeal (PIP) joint is the most frequently dislocated articulation in the human body, commonly trivialized as an uncomplicated sprain. Dorsal dislocations predominate and require immediate distinction between stable pure ligamentous avulsions and unstable fracture-subluxations involving more than 30% to 40% of the middle phalanx volar base.
• True Lateral Radiographic Imperative: Accurate diagnosis hinges upon a true lateral projection with perfectly superimposed condyles of the proximal phalanx. The presence of articular divergence, non-parallel joint margins, or dorsal widening (the “V-sign”) confirms persistent dorsal subluxation demanding active intervention.
• Stability Arc Dictates Management: Stable reductions require buddy taping and protected active motion within 72 hours. Dorsal fracture-subluxations maintaining concentric reduction up to 30° of flexion succeed with dorsal extension-block splinting (McElfresh protocol). Static immobilization beyond 14 days is strictly contraindicated due to rapid, irreversible collateral ligament and checkrein fibrosis.
• The Irreducible Kaplan Lesion: Complex metacarpophalangeal (MCP) dislocations feature buttonholing of the metacarpal head through the palmar plate, creating pathognomonic palmar skin puckering. Longitudinal traction is strictly contraindicated because it cinches the flexor tendons and lumbrical around the metacarpal neck; emergent open reduction via a dorsal or volar approach is required.
• Surgical Reconstruction for High-Grade Instability: Unstable PIP fracture-dislocations involving greater than 40% to 50% of the articular base or impacted pilon patterns require operative restoration via extension-block pinning (Ishiguro), dynamic external fixation (Suzuki frame), hemi-hamate autograft arthroplasty, or volar plate arthroplasty.

2. Anatomy

The interphalangeal and metacarpophalangeal articulations of the hand represent high-precision, low-tolerance mechanical systems. Functional stability relies on an intricate balance between static osteoligamentous restraints and dynamic tendon vectors.

Proximal Interphalangeal (PIP) Joint

The PIP joint is a bicondylar hinge (trochlea) articulation possessing an arc of motion from 0° extension to 100°–110° flexion. The asymmetric bicondylar head of the proximal phalanx articulates with two shallow concave facets on the middle phalanx base, separated by a median vertical ridge. Static stability is governed by the three-sided box configuration:

• Volar Plate: A dense, fibrocartilaginous structure forming the floor of the joint. Distally, it inserts firmly onto the subarticular volar tubercle of the middle phalanx base. Proximally, it bifurcates into two thick lateral extensions known as the checkrein ligaments, which anchor into the ventrolateral ridges of the proximal phalanx. The central proximal margin remains membranous, facilitating accordion-like folding during joint flexion. The volar plate acts as the primary static barrier preventing hyperextension.
• Proper Collateral Ligaments (PCL): Originates from the subcapital depression on the lateral condyle of the proximal phalanx and passes obliquely to insert onto the volar third of the middle phalanx base. The PCL is taut in flexion and serves as the primary coronal stabilizer.
• Accessory Collateral Ligaments (ACL): Originates just volar to the PCL and runs fan-shaped to insert directly into the lateral margin of the fibrocartilaginous volar plate. The ACL is taut in extension and functions primarily to suspend and centralize the volar plate.
• Extensor Apparatus: Dorsally, the extensor tendon trifurcates over the distal proximal phalanx. The central slip crosses the PIP joint to insert into the dorsal tubercle of the middle phalanx base, mediating active PIP extension. The lateral bands travel dorsolaterally across the joint, stabilized dorsal to the axis of rotation by the triangular ligament and tethered ventrally by the transverse retinacular ligament (TRL).

Metacarpophalangeal (MCP) Joint

The MCP joint is a multiaxial condyloid joint. The cam shape of the metacarpal head (wider volarly than dorsally) causes the collateral ligaments to become eccentric and tight in 60°–90° of flexion, while remaining lax in extension to permit lateral abduction and adduction.

• Volar Plate: Substantially thicker than at the PIP level, firmly attached to the proximal phalanx base and loosely attached proximally to the metacarpal neck via membranous tissue. Adjacent volar plates of digits II through V are interconnected by the robust deep transverse metacarpal ligament (DTML).
• Kaplan’s Musculotendinous Noose: Surrounding the metacarpal head of the index and little fingers, specific myofascial structures form a constricting collar during dorsal displacement. At the index finger, this anatomically defined noose comprises the flexor digitorum profundus and superficialis tendons ulnarly, the first lumbrical muscle radially, the superficial transverse palmar fascia proximally, and the displaced fibrocartilaginous volar plate distally.

Distal Interphalangeal (DIP) Joint

The DIP joint is a bicondylar hinge joint similar to the PIP joint but lacks thick checkrein ligaments. The volar plate is intimately adherent to the terminal extensor tendon insertion dorsally and the flexor digitorum profundus tendon ventrally. True dislocations are rare due to the short distal lever arm, dense skin attachments, and robust collateral envelopes; when they occur, they are frequently open injuries.

Neurovascular Danger Zones & Surgical Intervals

• Digital Neurovascular Bundles: Paired proper digital arteries and nerves travel along the ventrolateral borders of the digits, positioned immediately volar to Cleland’s ligament and dorsal to Grayson’s ligament. In complex dorsal MCP dislocations (Kaplan lesion), the radial digital neurovascular bundle of the index finger is stretched tightly over the protruding metacarpal head directly beneath the palmar skin, placing it at extreme risk during palmar incisions.
• Midaxial Approach: Placed along the neutral lateral line connecting the dorsal apices of the flexion creases with the joint in 90° flexion. Dorsal reflection preserves the extensor retinacular apparatus; volar elevation of the neurovascular bundle within Grayson’s ligament protects the digital bundle.
• Volar Bruner Zig-Zag Approach: Utilizes alternating oblique incisions angled at 60° across flexion creases. Permits direct visualization of the flexor sheath, A2/A4 pulleys, and volar plate. Requires meticulous elevation of full-thickness flaps to prevent neurovascular bundle transection at the flap corners.

3. Pathogenesis

Finger dislocations result from high-velocity impact, axial loading, hyperextension, or violent rotational torque delivered to the distal digit, most commonly during athletic ball-handling or fall onto an outstretched hand.

Proximal Interphalangeal Joint Mechanisms

• Dorsal PIP Dislocation: The most prevalent pattern (>85%). Initiated by severe hyperextension with or without axial compression. Hyperextension produces tensile failure of the distal insertion of the volar plate from the middle phalanx base. As the middle phalanx continues its dorsal path, the accessory collateral ligaments tear, followed by complete or partial rupture of the proper collateral ligaments. When coupled with axial load, the dorsal margin of the proximal phalanx shears off the volar lip of the middle phalanx base, converting a soft-tissue dislocation into an unstable fracture-dislocation.
• Volar PIP Dislocation: Rare (<5%) and clinically perilous. Caused by a direct blow to the dorsal aspect of the middle phalanx or forced flexion with rotary torque. Failure begins dorsally with traumatic rupture or avulsion of the central slip insertion from the middle phalanx base. Straight volar dislocations rupture both collateral ligaments and the central slip. Rotary volar dislocations occur when one condyle of the proximal phalanx herniates between the central slip and a lateral band; the lateral band slips volarly beneath the condylar head, buttonholing the joint and preventing closed reduction.
• Lateral PIP Dislocation: Caused by a sudden unilateral abduction or adduction force applied to an extended or slightly flexed digit. The primary proper collateral ligament ruptures, accompanied by partial tearing of the accessory collateral ligament and unilateral detachment of the volar plate.

Metacarpophalangeal Joint Mechanisms

• Simple (Subluxated) MCP Dislocation: Caused by hyperextension loading. The proximal phalanx rests in 60°–90° of hyperextension over the dorsum of the metacarpal head. The volar plate is peeled off the metacarpal neck but remains draped over the dorsal head without interposition. Longitudinal traction must be avoided, as it can draw the volar plate into the joint space.
• Complex (Irreducible / Kaplan) MCP Dislocation: Violent hyperextension combined with forced axial loading ruptures the membranous proximal attachment of the volar plate. The metacarpal head pierces through the palmar plate and herniates into the subpalmar space. The torn volar plate flips dorsally and lodges in the joint space between the metacarpal head and proximal phalanx base. The flexor tendons shift ulnarly, the lumbrical shifts radially, and together with the deep transverse metacarpal ligament, they form a tight tourniquet around the narrow metacarpal neck. Any applied longitudinal traction tightens this muscular-tendinous ring, locking the joint.

4. Natural History

Epidemiology & Cohort Demographics

Finger dislocations account for a substantial percentage of all sports-related hand injuries evaluated in acute care and orthopaedic settings. Ball-handling sports (basketball, football, rugby, volleyball, and handball) account for over 70% of acute presentations. The peak demographic incidence falls between 15 and 35 years of age, demonstrating a 2.5:1 male-to-female predominance. The PIP joint of the border digits (index and little) and long finger sustains the highest frequency of ligamentous trauma. Complex MCP dislocations occur most frequently at the index finger due to lack of an adjacent radial intermetacarpal ligament restraint, followed by the little finger.

Untreated Prognosis & Chronic Pathoanatomy

If mismanaged, neglected, or subjected to excessive static immobilization, finger dislocations result in permanent functional impairment:

• Chronic PIP Flexion Contracture: Static splinting beyond 14 days precipitates adaptive shortening of the collateral ligaments, contracture of the retrocondylar checkrein ligaments, and dense intra-articular adhesion formation, resulting in intractable loss of extension.
• Post-Traumatic Swan-Neck Deformity: Neglected dorsal dislocations with unhealed, attenuated volar plates result in progressive PIP hyperextension, reciprocal DIP flexion, and dorsal migration of the lateral bands.
• Post-Traumatic Boutonniere Deformity: Missed central slip avulsions following volar PIP dislocations permit the lateral bands to subluxate volarly below the joint’s transverse axis of rotation. Unopposed pull converts the lateral bands into primary PIP flexors while concentrating extension forces onto the distal phalanx, creating the classic PIP flexion and DIP hyperextension deformity.
• Rapid Post-Traumatic Osteoarthritis: Unreduced dorsal fracture-subluxations alter contact mechanics, shifting joint reactive forces onto the dorsal rim of the proximal phalanx trochlea. Persistent articular incongruity exceeding 1 to 2 mm leads to rapid chondral erosion, subchondral sclerosis, osteophyte formation, and crippling joint destruction.

5. Clinical Presentation

History

Patients report an acute traumatic event, such as a ball striking the extended fingertip (“jammed finger”), a direct fall, or an opponent’s jersey catching the digit. Salient historical points include:

• Direction and Vector of Deformity: Inquire whether the finger was bent backward (hyperextension) or twisted laterally.
• On-Field Manipulation: Document whether the patient, teammate, or coach attempted manual reduction on the sideline, noting whether a distinct “clunk” or persistent deformity followed.
• Neurovascular Symptoms: Acute onset of numbness, paresthesias, or severe throbbing distally.
• Chronicity: Time elapsed between the index injury and presentation (acute <48 hours vs subacute 1–3 weeks vs chronic >3 weeks).

Physical Examination

Examination begins with careful inspection prior to any manipulation. Swelling, ecchymosis, and rotational alignment must be documented systematically.

• Inspection & Skin Integrity: Evaluate for gross bayonet deformity, angular deviation, and open wounds. In complex MCP dislocations, observe for pathognomonic skin puckering or dimpling in the proximal palmar crease, caused by tension on the vertical fibers of the palmar aponeurosis.
• Rotational Alignment: In partial flexion, observe all fingernails to ensure planes of rotation are parallel. In full flexion, ensure all fingertips point toward the scaphoid tubercle. Digital overlap (scissoring) indicates rotational deformity or unilateral collateral ligament rupture.
• Neurovascular Assessment: Static two-point discrimination (normal <6 mm) along the radial and ulnar digital nerve distributions. Digital capillary refill (<2 seconds) and pulp turgor must be verified prior to administering digital nerve blocks.

Provocative physical examination maneuvers provide definitive diagnostic localization and quantify joint stability following reduction or under digital anesthesia:

6. Imaging and Diagnostic Studies

Plain Radiography

Plain radiographs represent the diagnostic gold standard. A standard trauma digit series must include true posteroanterior (PA), oblique, and true lateral projections centered directly over the affected joint.

• The True Lateral Projection: The single most critical projection. A true lateral PIP view requires exact superimposition of the proximal phalanx condyles, appearing radiographically as a single concentric circle. If the condyles do not overlap perfectly, the projection is oblique and will mask dorsal subluxation.
• The “V-Sign”: In a concentrically reduced PIP joint, the articular space between the proximal phalanx head and middle phalanx base is completely parallel. In subtle dorsal subluxation, the joint space widens volarly and converges dorsally, forming a distinct “V” pattern indicative of unreduced articular subluxation.
• Articular Fragment Quantification: On the true lateral view, calculate the percentage of the middle phalanx articular base fractured: fractures involving <30% of the base are stable; fractures involving 30% to 50% are tenuously stable; fractures involving >50% are inherently unstable due to loss of collateral ligament attachment to the phalanx shaft.
• Radiographic Findings in Complex MCP Dislocation: PA view demonstrates widening of the joint space and asymmetric proximal phalanx positioning. True lateral shows the base of the proximal phalanx resting dorsal to the metacarpal head with parallel shafts, accompanied by a pathognomonic sesamoid trapped inside the MCP joint space.

Computed Tomography (CT)

High-resolution thin-cut CT (≤1.0 mm slices) with 2D sagittal/coronal reformats and 3D volume rendering is indicated for high-energy pilon fracture-dislocations, impacted intra-articular fragments, or when planning operative hemi-hamate autograft or open reduction internal fixation.

Ultrasonography & Magnetic Resonance Imaging

Dynamic high-resolution musculoskeletal ultrasound reliably confirms volar plate tears, entrapment of the lateral bands, or collateral ligament stump displacement. MRI is reserved for chronic, unreduced, or recurrent instability cases to assess chondral loss and fibrous interposition.

7. Classification

Management is guided by validated anatomic and biomechanical classification systems that dictate closed versus open treatment pathways.

8. Treatment

Medical / Nonoperative

Nonoperative management is the gold standard for simple, reducible, and stable ligamentous dislocations, as well as stable fracture-dislocations involving less than 30% of the articular base.

• Closed Reduction of Dorsal PIP Dislocations: Provide local digital block anesthesia (1% lidocaine without epinephrine). Apply gentle axial traction combined with slight hyperextension to disengage the middle phalanx base, followed by direct volar translation on the middle phalanx while bringing the joint into 20°–30° of flexion. Confirm concentric reduction with an audible and palpable clunk.
• Closed Reduction of Volar PIP Dislocations: Apply traction with the MCP and PIP joints in slight flexion, applying dorsal pressure to the middle phalanx base. Following reduction, evaluate the central slip via the Elson test immediately. If the central slip is ruptured, the PIP joint must be immobilized in absolute extension for 6 weeks, leaving the DIP joint free for active flexion.
• Closed Reduction of Simple MCP Dislocations: Flex the wrist to relax the flexor tendons. Apply direct, gentle palmar-directed pressure over the dorsal base of the proximal phalanx, pushing it over the metacarpal head into flexion. Longitudinal traction must never be applied, as it converts a simple dislocation into an irreducible complex Kaplan lesion.
• Extension-Block Splinting (McElfresh Protocol): Indicated for stable Eaton Type IIIA fracture-dislocations maintaining concentric reduction in flexion. Under fluoroscopy, determine the extension angle where the joint begins to subluxate dorsally (e.g., 20°). Apply a rigid dorsal thermoplastic splint blocking extension at 10° greater flexion than the subluxation threshold (e.g., set splint at 30° of flexion). Permit immediate, unrestricted active flexion within the splint from post-reduction day 1. Advance the splint into extension by 10° to 15° weekly. Discontinue the splint at 3 to 4 weeks and transition to buddy taping during active tasks.
• Buddy Taping Protocol: Indicated for uncomplicated, stable Type I and Type II dorsal dislocations. Apply buddy taping to the adjacent uninjured digit immediately following reduction. Initiate immediate active motion. Avoid all static immobilization beyond 72 hours.

Operative

The goals of surgery are restoration of articular congruity, stable concentric joint reduction throughout the full motion arc, and initiation of early rehabilitation.

• Extension Block Pinning (Ishiguro Technique): Indicated for acute (<2 weeks) dorsal fracture-dislocations with a single large volar fragment involving 30% to 50% of the articular surface. The PIP joint is brought into full flexion. Under fluoroscopic control, a 1.0 mm or 1.2 mm K-wire is introduced percutaneously through the dorsal skin at a 45° angle into the proximal phalanx neck, directly abutting the dorsal articular lip of the middle phalanx base to act as a rigid mechanical extension block. The middle phalanx is then gently extended, impinging against the pin, which directs the base volarly to reduce the fracture fragment. A second transfixing K-wire can be placed across the PIP joint at 40° flexion for 3 to 4 weeks if needed.
• Dynamic External Fixation (Suzuki Frame / Compass Hinge): Indicated for highly comminuted Eaton Type IV pilon fractures or unstable Type IIIB fracture-dislocations. Utilizes the principle of continuous ligamentotaxis. Transverse K-wires are driven through the center of rotation of the proximal phalanx head and the middle phalanx shaft. The wires are bent into dynamic hooks connected by dental elastics or modular bars. The continuous elastic distraction maintains joint space and reduces articular fragments while permitting full active and passive flexion-extension exercises. Pins are removed at 4 to 6 weeks.
• Hemi-Hamate Autograft Arthroplasty: Indicated for chronic, neglected, or severely comminuted fracture-dislocations involving >50% of the middle phalanx base where local bone is non-reconstructible. The dorsal distal articular facet of the hamate matches the bicondylar anatomy of the middle phalanx base. Through a dorsal wrist incision, an osteochondral autograft is harvested from the 4th/5th carpometacarpal joint of the hamate. Through a volar Bruner or bilateral midaxial approach to the PIP, nonviable fragments are debrided, and the hamate graft is secured to the middle phalanx base using 1.0 mm to 1.3 mm micro-screws, restoring the volar buttress and permitting early active motion.
• Volar Plate Arthroplasty (Eaton-Malerich Technique): Indicated for comminuted volar lip fractures involving 30% to 50% of the joint base with intact dorsal articular bone, particularly in subacute injuries (2 to 6 weeks). Via a volar Bruner exposure, comminuted volar articular fragments are excised. The distal margin of the torn volar plate is mobilized, advanced into the bony defect at the middle phalanx base, and anchored into a prepared cancellous trough using pull-out transosseous sutures tied over a dorsal button or suture anchors. Postoperatively, dynamic extension-block splinting is initiated.
• Open Reduction of Complex (Kaplan) MCP Dislocation via Dorsal Approach: Preferred by many surgeons due to zero risk to the radial digital neurovascular bundle. A longitudinal incision is made over the dorsal MCP joint. The extensor mechanism is split longitudinally. The trapped volar plate, seen wedged between the metacarpal head and proximal phalanx base, is incised longitudinally in its midline, releasing tension and allowing the plate to slip back volarly while pushing the metacarpal head back into concentric reduction.
• Open Reduction of Complex (Kaplan) MCP Dislocation via Volar Approach: Provides direct access to the constricting structures. A zig-zag incision is centered over the palmar prominence. The radial digital neurovascular bundle, tented directly over the metacarpal head, must be identified and protected before deep incision. The A1 pulley is split, and the distal volar plate is divided or released from the deep transverse metacarpal ligament to achieve reduction.

Indications & Contraindications

Decision-making is driven by explicit quantitative metrics:

• Indications for Nonoperative Management: Concentric, congruent reduction achieved closed and maintained throughout an active extension arc ≥30°; volar middle phalanx avulsion fragment <30% of total articular depth; articular step-off <1.5 mm following reduction.
• Indications for Operative Intervention: Irreducible acute dislocation (complex Kaplan MCP, buttonholed rotary volar PIP); failure to maintain concentric reduction within 30° of flexion (joint subluxates dorsally at >30° flexion); involvement of >30% to 50% of the middle phalanx articular base on true lateral imaging; residual articular step-off ≥2.0 mm; complete gross collateral ligament instability with angular laxity >20° in full extension and absence of a firm endpoint; open dislocations requiring debridement and structural repair.
• Contraindications to Open Reconstruction: Severe local soft-tissue contamination or active infection (precludes internal fixation; dynamic external fixation indicated); severe patient non-compliance precluding adherence to dynamic rehabilitation protocols.

9. Outcome

Functional outcomes are directly correlated with the timeliness of concentric reduction and the rapidity with which protected active mobilization is established.

• Active Range of Motion (ROM) Expectations: Following simple dislocations treated with early protected functional motion, patients regain an average active PIP motion arc of 85°–95° (normal 0°–105°), with an average residual extension lag of 5°–8°. Total active motion (TAM) typically exceeds 240°. Across surgical cohorts with unstable fracture-dislocations (Ishiguro, dynamic external fixation, volar plate arthroplasty, and hemi-hamate autograft), average active PIP motion arc reaches 75°–80°. A mild extension lag of 10°–15° persists in approximately 40% of cases, though it rarely impairs functional hand grip.
• Patient-Reported Outcome Measures (PROMs): Validated instruments including the QuickDASH and Patient-Rated Wrist/Hand Evaluation (PRWE) demonstrate excellent functional restoration. Mean QuickDASH scores range from 4 to 12 points at 12 to 24 months post-injury across nonoperative and operatively stabilized groups. Grip strength routinely recovers to 85% to 95% of the contralateral uninjured extremity by 6 months.
• Return to Sport and Work Timelines: Athletes with simple dislocations may return to competition within 1 to 2 weeks utilizing protective thermoplastic splints or buddy taping, provided pain and swelling allow functional grasp. Following complex fracture-dislocations, non-contact athletics and light manual labor are permitted at 6 to 8 weeks; full collision sports, heavy manual loading, and unimpeded competition resume at 10 to 12 weeks following confirmed radiographic union and stability testing.

10. Complications

Complications following finger dislocations range from benign cosmetic enlargement to devastating joint stiffness and rapid degenerative destruction.

11. Pearls and Pitfalls

• Superimposed Condyle Diagnostic Pearl: Never accept an oblique radiograph to assess PIP joint reduction. The true lateral projection must demonstrate complete superimposition of the proximal phalanx condyles. If the two condylar outlines are distinct, subtle dorsal subluxation (the “V-sign”) will be obscured.
• Dynamic Fluoroscopic Stability Pearl: Never determine joint stability statically. Under digital anesthesia, take the PIP joint through an active or passive flexion-extension arc under live fluoroscopy. Identify the exact degree of extension at which the joint subluxates; this dictates the angle of the dorsal extension block.
• Traction Prohibition in Palmar Dimpling Pearl: If a dislocated MCP joint presents with a puckered or dimpled palmar crease, abandon all manual traction maneuvers immediately. Traction draws the flexor tendons and lumbrical tighter around the metacarpal neck, converting an anatomically salvageable injury into an incarcerated noose.
• Dorsal Approach Safety Pearl for Kaplan’s Lesion: When performing open reduction of a complex index MCP dislocation, use a dorsal longitudinal approach rather than a palmar incision. Splitting the extensor mechanism and dividing the interposed volar plate from behind eliminates the risk of transecting the stretched radial digital nerve.
• The 14-Day Immobilization Pitfall: Immobilizing a “jammed” PIP joint in a static aluminum splint for 4 to 6 weeks is the most common and catastrophic mistake in hand trauma. It produces permanent collateral ligament fibrosis and an uncorrectable 30°–40° flexion contracture.
• The Missed Central Slip Pitfall: Assuming a reduced volar PIP dislocation is an uncomplicated sprain guarantees a progressive Boutonniere deformity. Always perform Elson’s test; if PIP extension is absent against resistance, immobilize in complete extension for 6 weeks.
• The Excessive Flexion Splinting Pitfall: Splinting an unstable fracture-dislocation in >45° of flexion to maintain reduction causes rapid flexion contracture and dorsal skin sloughing. If the joint requires >30° of flexion to stay reduced, closed management has failed and surgical stabilization is mandatory.

12. Controversy

Dynamic External Fixation vs Hemi-Hamate vs Pinning for Large Fractures (>50% Base)

The optimal surgical reconstruction for comminuted, unstable PIP fracture-dislocations involving greater than 40% to 50% of the middle phalanx articular base remains intensely debated:

• Dynamic External Fixation: Proponents favor the Suzuki frame or commercial dynamic compass hinges because they rely on ligamentotaxis to restore length and joint space while permitting immediate active motion, avoiding donor site morbidity. However, critics point to high rates of pin tract infections (up to 15%), pin loosening, wire migration, and failure to anatomically reduce depressed central articular fragments.
• Hemi-Hamate Autograft Arthroplasty: Champions of osteochondral autografting emphasize that the dorsal articular facet of the hamate replicates the bicondylar anatomy and radius of curvature of the middle phalanx base, restoring a rigid bony volar buttress that permits early aggressive mobilization. Opponents emphasize that it is technically demanding, requires harvest from the carpus with potential donor-site wrist pain, and risks graft resorption or avascular nonunion.
• Extension Block Pinning (Ishiguro): Minimally invasive and technically straightforward, but universally recognized as ineffective if the volar lip is comminuted into multiple small fragments or in chronic injuries where remodeling capacity is absent.

Volar vs Dorsal Surgical Approach for Complex (Kaplan) MCP Dislocation

Controversy persists regarding the optimal surgical interval for irreducible complex MCP dislocations:

• The Volar Approach: Historically described by Kaplan, this approach offers direct, unobstructed exposure of the pathological noose (flexor tendons, lumbrical, and A1 pulley) and allows direct anatomic repair of the volar plate. However, the radial digital neurovascular bundle is tented over the prominent metacarpal head directly beneath the subcutaneous tissue, resulting in an unacceptably high rate of iatrogenic nerve laceration among junior surgeons.
• The Dorsal Approach: Increasingly preferred as the safest technique. The skin incision and extensor-splitting approach encounter no neurovascular structures. Longitudinal division of the displaced volar plate from behind allows it to reduce spontaneously volarly. Opponents argue that the volar plate cannot be repaired directly and that the deep metacarpal head must be pushed rather than pulled, but clinical series demonstrate identical stability and zero digital nerve injuries.

Supervised Hand Therapy vs Home Exercise Self-Management

Historically, all patients sustaining dorsal PIP dislocations or avulsion injuries were routinely referred for extensive, supervised occupational therapy involving custom orthoses, whirlpool, and manual mobilization. Modern Level I randomized controlled evidence (the multicenter PINOT trial by Salentijn et al., 2026) has demonstrated that an independent, home-based self-management exercise regimen using simple buddy taping is non-inferior to formal supervised hand therapy. Patients achieved equivalent DASH scores, identical active range of motion arcs, and comparable return-to-work timelines at 12 months, challenging the routine financial and healthcare utilization burden of formal hand therapy for uncomplicated injuries.

13. Evidence-Based Synthesis

Modern clinical decision-making is grounded in high-quality randomized controlled trials and prospective registry analyses, corroborated by seminal biomechanical and anatomical descriptions.

14. References

• Salentijn DA, Jawahier P, van Barreveld M et al. Self-Management Exercise Regimen Versus Supervised Hand Therapy in Patients With Dorsal Dislocation or Hyperextension Injury With a Volar Plate Avulsion of the Proximal Interphalangeal Joint: The Randomized Controlled PINOT Study. Hand (N Y). 2026. doi:10.1177/15589447261469595 [Level I (Therapeutic): Randomized Controlled Trial]
• Demino C, Yates M, Fowler JR. Surgical Management of Proximal Interphalangeal Joint Fracture-Dislocations: A Review of Outcomes. Hand (N Y). 2021. doi:10.1177/1558944719873152 [Level I (Therapeutic): Systematic Review / Meta-Analysis]
• McElfresh EC, Dobyns JH, O’Brien ET. Management of Fracture-Dislocation of the Proximal Interphalangeal Joints by Extension-Block Splinting. J Bone Joint Surg Am. 1972. doi:10.2106/00004623-197254080-00010 [Level IV (Therapeutic): Original Technique Description / Case Series]
• Kaplan EB. Dorsal Dislocation of the Metacarpophalangeal Joint of the Index Finger. J Bone Joint Surg Am. 1957. doi:10.2106/00004623-195739050-00008 [Level V (Expert Anatomical Description): Seminal Anatomic Description / Landmark Technique]
• Dionysian E, Eaton RG. The long-term outcome of volar plate arthroplasty of the proximal interphalangeal joint. J Hand Surg Am. 2000. doi:10.1016/s0363-5023(00)70026-8 [Level IV (Therapeutic): Long-Term Observational Cohort Study]

15. Master Class Pro-Tip

When managing acute dorsal PIP fracture-dislocations, assess concentric reduction under fluoroscopy through an active motion arc. If the joint remains concentrically reduced up to 30° of extension, closed extension-block splinting is indicated: block full extension by 10° beyond the point of subluxation, permit immediate unrestricted active flexion, and advance extension by 10° weekly. Prolonged static immobilization beyond 14 days causes irreversible collateral ligament shortening and permanent flexion contracture.

Master Class Surgical Pearl: Proximal Interphalangeal Joint Stability