Boutonnière Deformity — Reconstruction

Indication — when to operate. Reconstruction is offered for a chronic boutonnière deformity (greater than 6 to 12 weeks) with a supple PIP (passive extension to 0 degrees) that has either failed a fair trial of non-operative splinting or presented late, provided the patient has functional disability and can commit to a structured 12-week hand-therapy programme. The absolute indications are an open Zone III extensor injury with loss of active PIP extension (primary repair within 24 hours), a bony avulsion of the central slip displaced greater than 2 mm with articular incongruity (ORIF or reattachment), and persistent or recurrent deformity after 6 to 8 weeks of compliant full-time PIP extension splinting. Acute closed injuries are treated without surgery first. A closed central-slip injury within 2 weeks, with a positive Elson test but a supple PIP, is managed with full-time PIP extension splinting for 6 consecutive weeks with the DIP left completely free. The mechanism is mechanical: each DIP flexion pulls the lateral bands dorsally across the PIP joint, stretches the ORL and lets the central slip heal in its correct anatomical position. Reported success in compliant patients is 80 to 90 percent good or excellent (Evans; Coons and Green — outcomes deteriorate if splinting is started beyond 2 weeks). Contraindications. The absolute contraindication is a fixed PIP flexion contracture that cannot be passively extended to 0 degrees — it must be corrected first with serial casting or dynamic splinting. Active infection, an uncontrolled wound, and a patient unable to participate in structured hand therapy also preclude reconstruction. Relative contraindications are a mild deformity (less than 30 degrees PIP flexion) with little functional limitation, a comfortable low-demand finger in an elderly patient, and rheumatoid disease with uncontrolled synovitis (treat the synovitis first). The one decision — what to add once you are there. Every reconstruction begins by exposing the extensor mechanism over the PIP and confirming a supple joint. The choice of technique then follows the intraoperative findings:

Consent specifically for recurrence (approximately 15 percent at 5 years), residual PIP stiffness (a 10 to 20 degree flexion loss is common), swan-neck conversion from overcorrection, a permanent DIP extension lag if a Fowler tenotomy is added, infection (less than 1 percent), and the need for prolonged therapy compliance. Setup. Supine, arm on a hand table, upper-arm tourniquet, regional (supraclavicular or infraclavicular) block with sedation. Position the finger accessible and mark the PIP joint line. Loupe magnification is mandatory — the dorsal sensory nerves and the extensor mechanism are fine structures.

The goal: expose the extensor mechanism over the PIP through a dorsal curvilinear approach, confirm the joint is supple and the surface preserved, then rebuild central-slip extension by whichever technique the intraoperative findings allow — primary repair, a Matev lateral-band transfer, or both — and address any fixed DIP hyperextension with a Fowler tenotomy. The exposure is laid out in full as the first steps below.

View larger

Rehabilitation | Phase | Timing | Immobilisation | Therapy | |-------|--------|----------------|---------| | 1 | 0 to 6 weeks | Continuous PIP extension splint | DIP free; active DIP flexions 10 to 15 times every waking hour; splint off only for supervised wound care; sutures out at 14 days | | 2 | 6 to 8 weeks | Removable splint; night splinting continues | Supervised active PIP extension; gentle active PIP flexion from 30 to 60 degrees; never force passive flexion (repair weakest at 4 to 8 weeks) | | 3 | 8 to 12 weeks | Night splint only | Progressive active flexion and extension against gentle resistance; scar massage; grip strengthening from week 10 | | 4 | 12+ weeks | No splint | Full active ROM expected by 12 to 16 weeks; return to heavy manual work at 12 to 16 weeks; a permanent 10 to 20 degree PIP flexion loss is usual |

Complications

Failed primary reconstruction — patterns and revision. Recurrence within 6 weeks usually means inadequate splinting or therapy non-compliance — resume full-time PIP extension splinting for another 4 to 6 weeks. Recurrence at 6 to 12 weeks usually means the repair has stretched out — if the PIP is still supple, re-explore and revise with augmentation (tendon graft or lateral-band transfer). Recurrence after 12 weeks is established failure: if the lateral bands are intact and the PIP supple, a palmaris longus graft woven through the middle-phalanx base and lateral bands can reconstruct the central slip; if the PIP is stiff (less than 30 degrees passive extension), serial casting or dynamic splinting first; if the joint is arthritic or two reconstructions have failed, PIP arthrodesis in 20 to 30 degrees of flexion gives a stable, pain-free finger at the cost of PIP motion. Rheumatoid boutonnière — a different operation. The pathology is synovitis-driven attenuation of the central slip and dorsal capsule, not a discrete rupture; the lateral bands are pushed volar by hypertrophic synovium, so direct repair of the attenuated tissue is futile. Optimise the synovitis first (DMARDs, biologics). Once synovitis is controlled but a supple deformity persists, the operation is dorsal synovectomy plus lateral-band relocation (Matev-type) without attempting central-slip repair, with a Fowler tenotomy if DIP hyperextension persists. If the PIP is destroyed (greater than 50 percent joint-space loss, erosions), offer PIP arthrodesis (20 to 30 degrees flexion) or silicone arthroplasty in selected low-demand patients. Results are less predictable than traumatic cases — approximately 50 to 70 percent satisfactory — with higher recurrence from ongoing synovitis.

Pathomechanics. The boutonnière deformity begins with disruption of the central slip at Zone III. The central slip — the continuation of the common extensor tendon (EDC; EIP in the index, EDM in the small) — is the primary active extensor of the PIP (roughly 80 percent of extension power) and inserts on the dorsal base of the middle phalanx. Once it fails, the lateral bands lose their dorsal restraint and slide volar to the PIP axis of rotation, where each intrinsic contraction now flexes rather than extends the PIP. The volar migration also tethers the oblique retinacular ligament (ORL, Landsmeer's ligament), which runs from the volar flexor sheath at the proximal phalanx to the dorsal lateral bands/terminal tendon; the tightened ORL pulls the terminal tendon into extension, so the DIP hyperextension is a passive mechanical phenomenon rather than an active one. Surgical anatomy. In the uninjured finger the two lateral bands run dorsal to the PIP axis, receive contributions from the interossei, the lumbricals (radial side) and the extensor tendon, and converge distal to the PIP into the terminal tendon on the dorsal base of the distal phalanx. The transverse retinacular ligament (TRL) normally holds the lateral bands dorsally; its attenuation contributes to volar migration, and some techniques reef it to restore position. The central slip is relatively hypovascular (limited healing potential, prolonged protection needed after repair) while the lateral bands are well vascularised (good local transfer tissue). The dorsal capsule lies immediately deep to the central slip and is usually injured with it — repair both together.

Structures at risk during exposure. The dorsal digital nerves (radial-nerve branches to the index/middle/ring-radial, ulnar-nerve branches to the ring-ulnar/small) in the dorsal subcutaneous tissue can be divided if the incision is too lateral or dorsal. The extensor tendon itself is most often injured by overly aggressive post-operative mobilisation rather than the surgery. The PIP articular surface can be scored during dorsal capsulectomy or bony preparation. The contralateral lateral band must be protected during a Matev transfer, since both bands are needed for balanced function. Aetiology and epidemiology. Causes are traumatic (laceration, closed rupture, bony avulsion), inflammatory (rheumatoid, psoriatic arthritis) or iatrogenic (after Dupuytren release or PIP arthrolysis). Traumatic boutonnière most often follows a jaming injury or a Zone III laceration; rheumatoid boutonnière reflects pannus-driven attenuation rather than a discrete rupture and is part of a broader rheumatoid hand pattern. The Elson test is the gold-standard bedside confirmation of central-slip integrity. Rheumatoid boutonnière — why it is different. Synovitis attenuates the central slip and dorsal capsule without a discrete tendon rupture; hypertrophic synovium displaces the lateral bands volarly, and erosions and joint destruction may coexist. Direct repair of the attenuated tissue is futile, so the operation is synovectomy plus lateral-band relocation (Matev-type), with arthrodesis or arthroplasty reserved for a destroyed joint — a fundamentally different approach to the traumatic case.