A mallet finger is a common injury resulting from a forceful impact to the fingertip, causing a tear or disruption of the extensor tendon at the distal interphalangeal (DIP) joint. This injury leaves the fingertip unable to actively straighten, resting in a characteristic dropped or flexed position. While acute mallet injuries are typically managed with continuous splinting, treating a mallet finger years later requires different strategies. Successful correction of a long-standing mallet finger is possible, but treatment shifts dramatically from simple immobilization to complex surgical reconstruction.
How Time Changes a Mallet Finger Injury
The passage of years fundamentally alters the structures around the DIP joint, making late correction significantly more challenging than acute treatment. When the terminal extensor tendon ruptures, the unopposed pull of the flexor tendon keeps the fingertip bent. This causes the extensor tendon remnants to retract and become elongated.
This chronic imbalance leads to the formation of dense scar tissue (fibrosis) at the injury site, preventing the tendon ends from rejoining. The DIP joint capsule and collateral ligaments also tighten and shorten, creating fixed joint stiffness that resists passive straightening.
Furthermore, the extensor mechanism’s force is redirected to the proximal interphalangeal (PIP) joint. This can eventually lead to a compensatory hyperextension of the middle joint, known as a swan neck deformity. These fixed deformities and tissue changes are the physical barriers that must be overcome in delayed intervention.
Conservative Management for Chronic Cases
For a mallet finger that has persisted for years, conservative options like traditional continuous extension splinting are rarely effective for fully correcting the deformity. Splinting works best in acute cases when the tendon tear is fresh and the joint remains flexible. Once fixed stiffness and scar tissue have developed, simply holding the finger straight will not reverse the structural changes.
Non-operative management in chronic cases focuses on improving function, managing pain, and addressing secondary stiffness, rather than achieving complete extension. Occupational therapy uses stretching exercises and passive range-of-motion maneuvers to soften scar tissue and loosen contracted ligaments.
Dynamic splinting, which uses tension to gradually pull the joint into a better position, may be employed over several months to regain a few degrees of extension. However, if the joint cannot be passively straightened by a clinician, these conservative methods are unlikely to achieve the desired correction, making surgical intervention the more reliable path.
Surgical Reconstruction Strategies
Surgical treatment for a chronic mallet finger is reserved for deformities that are functionally limiting, cosmetically unacceptable, or those that have led to a secondary swan neck deformity. The choice of procedure depends heavily on whether the DIP joint remains flexible and the severity of any joint degeneration. The goal is to restore the extensor mechanism’s balance and re-establish the ability to straighten the fingertip.
Tendon Reconstruction
For flexible deformities where joint cartilage is healthy, the strategy involves tendon reconstruction or shortening. Techniques like tenodermodesis involve excising a small segment of the elongated tendon and overlying skin, then repairing the shortened tendon directly to the bone at the DIP joint. Another approach is a tendon shortening procedure, such as step-plasty, where the elongated extensor tendon is cut in a Z-shape to remove excess length before being sutured back together. In cases with a severe tendon gap, a tendon graft may be necessary to bridge the defect and recreate the terminal tendon.
Joint Fusion (Arthrodesis)
For severe, long-standing cases characterized by a fixed flexion contracture, significant joint stiffness, or advanced osteoarthritis, the definitive solution is distal interphalangeal joint arthrodesis, or fusion. This procedure involves surgically removing the damaged cartilage surfaces and fixing the two bones of the joint together with pins or a screw until they grow into a single, stable unit. Fusion eliminates movement at the DIP joint, but it provides a permanent, stable, and pain-free fingertip positioned in slight flexion. This is a highly functional position for grasping and pinching, sacrificing motion for stability and correction.
Expected Outcomes and Recovery Timeline
Regardless of the technique used, the expected outcome following surgical repair of a chronic mallet finger focuses on functional improvement rather than achieving a perfect, pre-injury state. For tendon repair, an acceptable result often includes a residual extensor lag of up to 10 to 20 degrees, which is considered a good functional outcome. Full, active range of motion is rare, particularly when the injury has been chronic, due to scar tissue and joint capsule tightness.
Recovery is a lengthy process beginning with strict immobilization, typically involving pins or a splint, for six to eight weeks to allow the reconstructed tendon or fused bone to heal. Following this initial phase, an intensive course of hand therapy is required, often lasting several months, to manage stiffness and restore motion to adjacent joints.
Potential complications include:
- Recurrence of the droop.
- Infection.
- Nail bed injury.
- Persistent joint stiffness and pain.
Patients undergoing joint fusion can expect a stable, pain-free joint once the bone is healed, but the loss of motion at the fingertip is permanent.