Management of volar base middle phalanx fractures with dorsal subluxation · advanced
- Stability depends on the remaining intact volar articular surface of the middle phalanx. Fractures involving less than 30 percent are typically stable in flexion; those greater than 50 percent are inherently unstable.
- The primary goal is concentric joint reduction, NOT perfect anatomic articular restoration. A concentrically reduced joint that is mobilised early will remodel and function better than an anatomic articular reduction that is stiff.
- Treatment algorithm: stable patterns get dorsal block splinting. Unstable patterns require surgery: extension block pinning (small fragments), ORIF (large single fragments), dynamic external fixation (comminuted, pilon), or volar plate arthroplasty / hemi-hamate autograft (chronic or severely comminuted volar base).
- Early controlled active motion is critical. The PIP joint is extremely prone to stiffness, flexion contractures, and post-traumatic arthritis.
- “Always check a true lateral radiograph post-reduction. A V-sign (dorsal divergence of the joint space) indicates persistent dorsal subluxation and is unacceptable.
- “In extension block pinning, the pin goes into the proximal phalanx head to block extension, not across the joint. The joint must be concentrically reduced in the permitted arc of flexion.
- “Volar plate arthroplasty (Eaton) advances the volar plate into the fracture defect to resurface the joint and restore volar restraint. It requires a Bruner or midaxial approach.
- “Hemi-hamate autograft is reserved for large, un-reconstructable volar base defects (typically greater than 40 percent) and provides a concave cartilaginous surface that matches the middle phalanx.
When & Why
The problem. A dorsal PIP fracture-dislocation is a volar base fracture of the middle phalanx with dorsal subluxation of the middle phalanx on the proximal phalanx head. The volar plate has avulsed (with or without a bony fragment) from its distal attachment, so the joint has lost its primary restraint to dorsal translation. The operation exists to restore a concentric, stable, mobile joint. Which operation, when. The decision is driven by two things — the size of the volar fragment and whether the joint can be held concentric. The same volar exposure serves every operation that needs one.
- Stability
- Stable in less than 30 degrees flexion
- Recommended treatment
- Dorsal block splinting, early active motion
- Stability
- Borderline
- Recommended treatment
- Extension block pinning if unstable in splint
- Stability
- Unstable
- Recommended treatment
- ORIF via volar approach with lag screws
- Stability
- Unstable
- Recommended treatment
- Dynamic external fixation (Suzuki frame) by ligamentotaxis
- Stability
- Subluxated
- Recommended treatment
- Volar plate arthroplasty (Eaton) or hemi-hamate autograft
Absolute indications for surgery - Joint irreducible by closed means (soft tissue interposition, typically the volar plate or a lateral band).
- Persistent dorsal subluxation (V-sign) despite flexing to 30 to 40 degrees.
- Unstable fracture pattern requiring more than 40 degrees of flexion to maintain reduction.
- Open fracture-dislocations.
- Chronic or missed fracture-dislocations (greater than 3 weeks). Relative indications - Large, single volar fragment representing greater than 40 percent of the articular surface (amenable to ORIF).
- Patient inability to comply with a strict splinting and supervised therapy protocol.
- Significant articular step-off (greater than 2 mm) in a large, fixable fragment. Contraindications - Stable joint concentricity maintained in less than 30 degrees of flexion (manage with dorsal block splinting).
- Extremely sedentary patient with low functional demands (relative).
- Severe peripheral vascular disease or active infection in the digit. Consent specifically for permanent joint enlargement and swelling (almost universal), loss of some terminal extension or full flexion, pin-tract infection (especially with external fixation), hardware prominence needing later removal, post-traumatic arthritis, and a small chance of reoperation for stiffness or recurrent subluxation. Counsel that the goal is a painless, stable, mobile arc — not a perfectly normal finger. Setup. Supine with the arm on a radiolucent hand table. Upper-arm tourniquet inflated to 250 mmHg. Regional block (axillary or supraclavicular) or general anaesthesia; WALANT suits simpler pinning but is less ideal for complex ORIF or arthroplasty where deep dissection and a bloodless field are needed. Equipment: mini C-arm (fluoroscopy), K-wires (1.1 mm and 1.6 mm), a mini-fragment screw set (1.0 mm, 1.2 mm), rubber bands or suture for the dynamic fixator, and a micro-sagittal saw for the hemi-hamate graft.
The Operation
The goal is one operation, reached through one exposure: a volar approach to the PIP joint that exposes the volar plate and the fracture while protecting the neurovascular bundles, the flexor tendons and the extensor mechanism. The exposure is laid out in full below (and in depth on the Bruner volar zigzag approach and midaxial approach pages). After exposure, fixation is chosen to match the fragment pattern.
Operative sequence (volar approach for PIP fracture-dislocation)
- Supine, arm on a radiolucent hand table, upper-arm tourniquet to 250 mmHg, mini C-arm positioned for true lateral imaging.
- Plan a VOLAR exposure — a Bruner (zigzag) incision over the PIP joint, or a midaxial approach. A dorsal approach must NOT be used for a volar base fracture: it splits the extensor mechanism, risks central-slip attenuation and scarring, and cannot reach the volar plate directly.
- Bruner: a zigzag incision over the volar PIP joint with the apices reaching the midaxial line. Elevate full-thickness flaps, keeping the neurovascular bundles protected within the flaps. The zigzag lengthens the scar and prevents a volar flexion contracture.
- Midaxial: incise along the midlateral line (flex the finger to mark it between the palpable condyles). The neurovascular bundle lies just volar to the incision and is identified early and protected.
- In both, the neurovascular bundles are the structures you must protect throughout — they run volar to the flexor sheath, lateral to the tendons.
- Identify the A3 pulley over the PIP joint and divide it longitudinally to expose the flexor tendons. The A2 (over the proximal phalanx) and A4 (over the middle phalanx) pulleys MUST be preserved to prevent bowstringing.
- Retract the FDS and FDP tendons laterally (a Penrose drain helps). This brings the volar plate into view — in a fracture-dislocation it remains attached to the avulsed volar base fragment.
- Hyperextend (or gently distract) the PIP joint to look directly down onto the articular surfaces — the 'shotgun' exposure — taking care not to completely disrupt the collateral ligaments.
- Irrigate to clear haematoma and any interposed soft tissue. Define the fracture bed, the articular margins and the size of the volar fragment. This inspection determines which fixation follows.
- For an unstable joint where the fragment is too small or comminuted for ORIF but the joint reduces in flexion, pinning is the workhorse.
- Reduce the joint under fluoroscopy (longitudinal traction, flex the PIP), and find the angle of flexion at which the joint is concentric (for example 40 degrees).
- Drive a 1.1 mm K-wire dorsally into the HEAD of the proximal phalanx, angled distally so it protrudes to act as a physical bumper. The pin does NOT cross the joint — it blocks the middle phalanx from extending past the stable angle.
- Confirm on a true lateral that the joint is concentric in the permitted arc and that, as the finger extends, the dorsal base of the middle phalanx abuts the pin and stops. Cut and bend the pin outside the skin.
- Reduce the volar base fragment anatomically with a dental pick or small reduction forceps, prioritising the joint surface over the metaphyseal cortex.
- Hold temporarily with a 0.8 mm K-wire, then fix with one or two 1.0 mm or 1.2 mm lag screws, countersunk so the heads do not impinge on the flexor tendons or the joint.
- If the fragment is highly comminuted, stop — ORIF will fail. Convert to volar plate arthroplasty, a dynamic external fixator, or hemi-hamate (Steps 7-9).
- Excise the comminuted, un-reconstructable bony fragments from the volar base. Preserve the lateral collateral ligament insertions if possible.
- Create a smooth transverse trough at the volar base of the middle phalanx with a rongeur or fine burr — the trough receives the advanced volar plate.
- Release the check-rein ligaments proximally if the plate will not reach. Pass two strong non-absorbable sutures (2-0 or 3-0 Ethibond) through the distal margin of the volar plate with a grasping Krackow or Bunnell technique.
- Drill two parallel holes from the volar trough dorsally through the middle phalanx, exiting just distal to the dorsal articular margin. Pass the sutures through to the dorsal aspect.
- Reduce the joint concentrically, hold it in 20 to 30 degrees of flexion, and tie the sutures tightly over the dorsal cortex (or over a small button on the skin). The volar plate now resurfaces the defect and tethers against dorsal subluxation. Protect the repair with a transarticular 1.1 mm K-wire in 20 to 30 degrees of flexion for 2 to 3 weeks.
- The critical step is the proximal axis pin: insert a 1.1 mm K-wire transversely through the TRUE axis of rotation of the proximal phalanx head (the centre of the concentric circles of the condyles on the lateral view).
- Insert a second 1.1 mm K-wire transversely through the middle phalanx, distal to the fracture and clear of the joint.
- Bend the proximal pin ends 90 degrees distally and the distal pin ends 90 degrees proximally; form hooks and apply elastic bands between each side to generate longitudinal traction (ligamentotaxis).
- Under fluoroscopy confirm the traction distracts the joint symmetrically and reduces the fragments. Passively flex and extend — motion must be concentric. If the joint hinges open, the proximal pin is off-axis and must be repositioned.
- Excise the volar fragments to create a clean rectangular defect at the volar base of the middle phalanx. Measure the defect (width, depth, articular arc).
- Make a longitudinal incision over the 4th and 5th carpometacarpal joints and expose the distal articular surface of the hamate. The ridge between the 4th and 5th metacarpal facets matches the median ridge of the middle phalanx base.
- Harvest an osteochondral graft matching the defect exactly, using an oscillating saw and osteotomes.
- Fit the graft snugly into the defect and fix with two or three 1.0 mm or 1.2 mm lag screws, the articular surface flush with the native dorsal cartilage. Confirm concentric, stable reduction under fluoroscopy.
- Check the reduction under fluoroscopy through a full arc — the joint MUST be concentrically reduced.
- Repair the flexor sheath (A3) if tension allows; leaving it open is acceptable. Let the flexor tendons fall back into place and close the skin with non-absorbable sutures.
- Apply a dorsal blocking splint with the PIP in 20 to 30 degrees of flexion, incorporating any extension-block or transarticular pin.
A V-sign on the true lateral radiograph (the joint space diverging dorsally) means persistent dorsal subluxation. This is unacceptable at any stage — intra-operatively or at follow-up — and leads to rapid joint destruction. If closed reduction and splinting cannot maintain parallel joint surfaces, surgical stabilisation is required. Never accept a non-concentric reduction to avoid a return to theatre.
The pin does NOT cross the PIP joint. It is a single K-wire driven dorsally into the head of the PROXIMAL phalanx, angled distally so it protrudes and acts as a bumper against the dorsal base of the middle phalanx. The angle is set by the flexion at which the joint is concentric — if stable at 40 degrees, the pin blocks extension beyond 40 degrees. As the finger extends, the middle phalanx hits the pin and the joint stays concentric.
Volar base fractures require a volar (Bruner or midaxial) approach to directly visualise the volar plate, the fragments and the articular surface without disrupting the extensor mechanism. A dorsal approach splits the central slip and lateral bands, risks scarring and central-slip attenuation (an extensor lag), and still cannot reach the volar pathology. Reserve dorsal approaches for dorsal lip fractures and true volar dislocations that injure the central slip.
Aftercare & Complications
Rehabilitation | Phase | Timing | Immobilisation | Therapy | |-------|--------|----------------|---------| | 1 | Days 0-21 | Dorsal blocking splint at 20-30 degrees flexion (transarticular K-wire for Eaton arthroplasty for 2-3 weeks) | Active flexion and extension within the splint/pin limits, started immediately; therapy supervision | | 2 | Weeks 3-6 | K-wires removed at 3-4 weeks; splint gradually straightened by ~10 degrees per week | Regain terminal extension while keeping the flexion arc; buddy taping for protection | | 3 | Weeks 6-12 | Splint weaned; dynamic extension splint (e.g. Capener) if a flexion contracture persists | Strengthening after clinical and radiographic union (6-8 weeks) | Most patients return to desk work by 6 to 8 weeks and heavier manual tasks by 12 weeks. Set the expectation early: the PIP joint will stay permanently thicker than the other side and some loss of terminal extension is normal — the win is a painless, stable, functional arc. Special case — chronic fracture-dislocations (over 3 to 4 weeks) The fracture has often malunited, the volar plate is heavily scarred, the collateral ligaments are contracted, and the articular cartilage may be damaged from chronic subluxation. Closed reduction is impossible and ORIF usually fails (callus, bone resorption, cartilage damage). Volar plate arthroplasty is highly effective for chronic cases, providing a fresh gliding surface; for very large defects in young patients, hemi-hamate reconstructs the articular contour with hyaline cartilage. Outcomes are worse than for acute injuries — counsel explicitly for a permanent loss of motion (often 20 to 30 degrees of terminal extension) and a permanently swollen joint. Complications
- Incidence
- Very high (30-50 percent)
- Recognition
- Inability to fully extend or flex; rigid joint at follow-up
- Management
- Prevent with early active motion and immobilisation under 3-4 weeks; hand therapy, dynamic splinting, surgical contracture release if functionally limiting
- Incidence
- Moderate (10-20 percent)
- Recognition
- V-sign on the lateral X-ray; widened dorsally; early pain and stiffness
- Management
- Unacceptable — return to theatre for revision fixation, external fixation or volar plate arthroplasty; ignoring it guarantees rapid joint destruction
- Incidence
- High with external fixators (up to 20 percent)
- Recognition
- Erythema, discharge and pain around K-wire sites
- Management
- Oral antibiotics and local wound care; rarely early pin removal unless deep infection or osteomyelitis is suspected; pin-care protocols essential
- Incidence
- High in long-term follow-up
- Recognition
- Progressive pain, swelling and motion loss months to years later; joint-space narrowing
- Management
- NSAIDs, splinting, corticosteroid injection; salvage with PIP arthrodesis (position varies by digit) or arthroplasty (silicone or surface replacement)
- Incidence
- Moderate (with ORIF)
- Recognition
- Pain over screw heads, limited flexor excursion, catching in motion
- Management
- Countersink screws at the index operation; remove hardware once united if symptomatic
Viva & Exam Focus
S.T.A.B.L.ES.T.A.B.L.E — algorithm for PIP fracture-dislocations
P.I.N.SP.I.N.S — Suzuki frame components
The trap: accepting a lateral where the joint space is not perfectly parallel — a V opening dorsally means persistent dorsal subluxation of the middle phalanx. The fix: this is unacceptable and leads to rapid joint destruction. The reduction must be concentric; if splinting cannot maintain parallel surfaces, surgical stabilisation is required.
The trap: immobilising the PIP joint longer than 3 to 4 weeks to wait for union. The fix: the PIP joint tolerates immobilisation poorly and stiffness is the commonest complication. Every treatment aims for early controlled motion within a safe arc, usually within days.
The trap: fixing a highly comminuted volar base with multiple tiny screws. The fix: comminuted fragments lose blood supply and fail under ORIF. Dynamic external fixation uses ligamentotaxis to restore joint space and allow motion — superior for pilon-type fractures.
The trap: focusing only on the volar fracture and missing a concomitant central slip rupture. The fix: dorsal fracture-dislocations (volar lip fractures) are most common, but volar dislocations (dorsal lip fractures) occur and disrupt the central slip. Always assess the mechanism and the exact pattern.
The trap: placing the extension-block pin too far distally or proximally so it fails to block the middle phalanx at the right angle. The fix: drive the pin into the head of the proximal phalanx, intra-articular but avoiding the central load-bearing cartilage, to block extension at the angle where the joint is concentric.
The trap: using a dorsal approach for a volar base fracture. The fix: volar base fractures need a volar (Bruner) or midaxial approach to visualise the volar plate, the fragments and the articular surface without disrupting the extensor mechanism.
Clinical Decision Scenarios
Practise clinical reasoning and management decisions out loud
“A 25-year-old basketball player has a dorsal PIP fracture-dislocation of his middle finger sustained 2 weeks ago. X-rays show a volar base fracture of about 45 percent of the articular surface, and the joint remains dorsally subluxated despite splinting. How will you manage this?”
“Explain the biomechanical principle of extension block pinning for PIP fracture-dislocations. Where exactly does the pin go?”
“A 40-year-old manual worker has a 6-week-old PIP fracture-dislocation of the index finger. The joint is stiff, swollen and dorsally subluxated, and the volar base fragment involves 60 percent of the articular surface. What is your surgical plan?”
Assessment & imaging
- True lateral X-ray is critical: assess articular-surface percentage and concentricity.
- V-sign (dorsal divergence) means persistent dorsal subluxation — unacceptable.
- Less than 30 percent articular involvement: usually stable.
- Greater than 50 percent articular involvement: inherently unstable.
Treatment algorithm
- Stable (less than 30 percent): dorsal block splinting, early active motion.
- Unstable, small fragments: extension block pinning.
- Unstable, large single fragment (greater than 40 percent): ORIF via volar approach.
- Highly comminuted (pilon): dynamic external fixation (Suzuki frame).
- Chronic or unfixable volar defect: volar plate arthroplasty (Eaton) or hemi-hamate autograft.
Surgical approaches
- Volar fractures require a volar approach (Bruner or midaxial).
- Do not use a dorsal approach for a volar fracture — it risks the extensor mechanism and central slip.
- Protect the neurovascular bundles; retract the flexor tendons laterally after dividing the A3 pulley.
- Preserve the A2 and A4 pulleys to prevent bowstringing.
Key complications
- Stiffness and flexion contracture: most common — prevent with early motion; avoid immobilisation beyond 4 weeks.
- Post-traumatic arthritis: high risk from cartilage damage.
- Pin-tract infection: common with dynamic external fixators.
- Recurrent instability: usually from accepting a non-concentric reduction.
Background & Evidence
PIP joint anatomy relevant to the operation. - Bony architecture: the proximal phalanx head has two condyles separated by an intercondylar notch, wider volarly than dorsally — this condylar shape drives the cam effect of the collateral ligaments. The middle phalanx base has two concave facets separated by a median ridge that match the condyles. The geometry makes the joint a tight hinge (about 0 to 110 degrees) with inherent anteroposterior stability.
- Ligamentous restraints: the proper collateral ligaments originate dorsally on the proximal phalanx head and insert on the volar-lateral middle phalanx base (taut in flexion); the accessory collateral ligaments lie volar to them and insert into the volar plate (taut in extension). The volar plate is a thick fibrocartilaginous restraint to hyperextension, held proximally by the check-rein ligaments and inserted distally into the volar base of the middle phalanx. In a dorsal dislocation the volar plate ruptures distally or avulses a bony fragment; the check-reins usually stay intact.
- Extensor mechanism: the central slip inserts into the dorsal base of the middle phalanx (extends the PIP); the lateral bands diverge dorsally around the joint, held by the transverse retinacular ligaments. This is why a dorsal approach is avoided for volar pathology.
- Neurovascular bundles & flexor sheath: the digital arteries and nerves run volar to the sheath; the FDS bifurcates (Chiasma of Camper) over the proximal phalanx to insert on the middle phalanx, and FDP continues to the distal phalanx. The tendons are retracted laterally to reach the volar plate; the A3 pulley over the PIP joint may be divided, but A2 and A4 must be preserved.
- Stability in flexion
- Stable
- Typical management
- Dorsal block splinting, early active motion
- Stability in flexion
- Borderline
- Typical management
- Extension block pinning if unstable in splint
- Stability in flexion
- Inherently unstable
- Typical management
- ORIF, dynamic external fixation, volar plate arthroplasty or hemi-hamate
Evidence by modality. Non-operative dorsal block splinting gives excellent results for stable patterns (less than 30 percent), with comparable or superior outcomes to surgery by avoiding surgical trauma and stiffness. Extension block pinning (McElfresh, 1972) reliably stabilises the joint while permitting the early flexion on which cartilage nutrition depends, and remains the workhorse for unstable, unfixable dorsal fracture-dislocations. Dynamic external fixation (Agee's force-couple principle, 1978; the Suzuki pins-and-rubbers frame, 1994) uses ligamentotaxis to align comminuted fragments and allows active motion — pin-tract infection is common but functional arcs of 70 to 80 degrees are typical for otherwise unreconstructable pilon fractures. Volar plate arthroplasty (Eaton and Malerich, 1980) reliably restores stability and a smooth gliding surface for comminuted or chronic volar base fractures, at the cost of about 10 to 15 degrees of lost terminal extension. Hemi-hamate autograft is reserved for large unreconstructable volar defects (greater than 50 percent) and restores near-normal anatomy with good graft incorporation, though donor-site hamate pain can occur.
References
Volar plate arthroplasty of the proximal interphalangeal joint: a review of ten years' experience
- Original description and long-term results of volar plate arthroplasty.
- Demonstrated reliable restoration of stability and a functional arc of motion.
- Patients typically lost an average of 14 degrees of terminal extension.
Unstable fracture dislocations of the proximal interphalangeal joint of the fingers: a preliminary report of a new treatment technique
- Described the force-couple principle for dynamic external fixation of the PIP joint.
- Maintained joint reduction via ligamentotaxis while permitting active motion.
- Established the foundation for modern dynamic fixators such as the Suzuki frame.
Management of fracture-dislocation of the proximal interphalangeal joints by extension-block splinting
- Introduced the concept of placing a pin in the proximal phalanx head to mechanically block extension.
- Permitted early active flexion while preventing dorsal subluxation.
- Demonstrated excellent return of motion compared with static splinting or prolonged immobilisation.
The pins and rubbers traction system for treatment of comminuted intraarticular fractures and fracture-dislocations in the hand
- Described the simple, inexpensive pin-and-rubber-band dynamic fixator for PIP fractures.
- Showed excellent restoration of joint space and motion in highly comminuted fractures.
- Highlighted the necessity of placing the proximal pin exactly in the axis of rotation.