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Mallet Finger – Comprehensive Medical Guide

Overview

Mallet finger (also called baseball finger, drop finger, or extensor tendon rupture) is a deformity of the fingertip in which the distal interphalangeal (DIP) joint cannot be actively extended. The fingertip droops and the patient is unable to straighten the tip of the finger.

• Typical population: Athletes who play ball sports (baseball, basketball, volleyball), manual workers, and anyone who suffers a sudden impact to the fingertip.
• Age distribution: Most common in adolescents and young adults (15‑35 years) but can occur at any age.
• Prevalence: Exact population‑wide rates are not well documented, but in a U.S. emergency‑department series of 1,200 hand injuries, mallet finger accounted for approximately 9 % of fingertip injuries [1].

Symptoms

Symptoms often appear immediately after the injury, but they can be delayed if the trauma is minor.

• Drooping fingertip – The last joint (DIP) remains in a flexed position.
• Inability to actively extend the tip – Passive extension is usually still possible.
• Pain at the base of the fingertip – Tenderness over the dorsal‑volar aspect of the DIP joint.
• Swelling or bruising – May be modest or pronounced depending on trauma severity.
• Visible gap in the extensor tendon – In cases of an avulsion fracture, a small bone fragment may be palpable.
• Stiffness or decreased range of motion – Especially after a few days of immobilisation.

Causes and Risk Factors

Primary cause

The hallmark mechanism is an abrupt force that forces the distal phalanx into flexion while the extensor tendon is contracting. This can:

• Rupture the tendon from its insertion on the distal phalanx (pure tendon rupture).
• Pull off a fragment of bone (avulsion fracture).

Common scenarios

• Ball striking the tip of an outstretched finger (baseball, basketball, racquet sports).
• Contusion from a door, a heavy object, or a fall.
• Forceful grasping of a hard object (e.g., a screwdriver) that snaps the tip into flexion.

Risk factors

• Sports participation – Especially contact and ball‑sports.
• Occupational hazards – Construction, mechanics, or any job with frequent hand impact.
• Previous tendon pathology – Tendon degeneration (e.g., from rheumatoid arthritis) makes rupture more likely.
• Age‑related bone density changes – In older adults, an avulsion fracture is more common.
• Inadequate protective equipment – Lack of finger guards or taping in sports.

Diagnosis

Diagnosis is primarily clinical, supported by imaging when needed.

History and physical examination

• Ask about the mechanism of injury, onset of symptoms, and any prior hand problems.
• Observe the drooping DIP joint and test active extension.
• Assess for tenderness, swelling, and check for any palpable bony fragments.

Imaging studies

• X‑ray (postero‑anterior and lateral views) – Recommended for all suspected mallet injuries to rule out an avulsion fracture, intra‑articular involvement, or associated injuries. Classification systems (e.g., Doyle) are based on radiographic findings [2].
• Ultrasound – Can visualize tendon discontinuity, especially useful when X‑ray is normal but clinical suspicion remains high.
• MRI – Reserved for complex cases (e.g., chronic injuries, suspicion of concomitant ligament damage).

Treatment Options

The goal of treatment is to maintain the DIP joint in extension until the tendon (or bone fragment) heals, typically 6‑8 weeks.

Non‑surgical (conservative) management

• Splinting – The cornerstone of therapy. A rigid or semi‑rigid “stack splint,” “crush splint,” or aluminum “safety splint” holds the DIP joint in 0‑10° of extension.
  • Duration: 6–8 weeks continuous wear (24 h/day).
  • After immobilisation, a gradual weaning protocol (2‑3 weeks) is advised to restore motion and prevent stiffness.
• Pain control – Over‑the‑counter NSAIDs (ibuprofen 400‑600 mg q6‑8 h) for the first few days; avoid prolonged use without physician guidance.
• Hand therapy – Once splint removal begins, a certified hand therapist can guide gentle range‑of‑motion and strengthening exercises.

Surgical intervention

Surgery is considered when any of the following are present (Doyle classification):

• Large avulsion fracture involving >30 % of the articular surface.
• Joint subluxation or instability.
• Open (skin‑penetrating) injuries.
• Failed non‑operative treatment after 3 weeks (persistent extensor lag).

Typical procedures include:

• Direct tendon repair – Suturing the torn tendon back to the distal phalanx.
• Fixation of bone fragment – Using a small K‑wire or a pull‑out suture technique.
• Viscoelastic or ligament augmentation – In chronic cases.

Post‑operative care also involves splinting for 4‑6 weeks, followed by hand‑therapy protocols similar to conservative treatment.

Medications

• NSAIDs for pain and inflammation (as above).
• Short‑course oral steroids are **not** routinely recommended; they may mask infection in open injuries.

Living with Mallet Finger

Even after successful treatment, patients often need to adjust daily habits during the healing phase.

Daily management tips

• Keep the splint dry – Use a waterproof cover while showering; drying the hand thoroughly prevents skin maceration.
• Avoid activities that stress the DIP joint – Refrain from typing, playing instruments, or sports that involve gripping for the first 4–6 weeks.
• Monitor skin integrity – Look for pressure sores, redness, or swelling under the splint; adjust or replace the splint if needed.
• Gentle active motion of the proximal joints – Move the PIP and MCP joints to prevent stiffness, unless instructed otherwise.
• Cold therapy – Ice packs for 15 minutes, 3–4 times daily can reduce swelling during the first week.
• Follow‑up appointments – Typically at 1, 3, and 6 weeks to confirm proper alignment and healing on X‑ray.

Return to activities

Most patients resume normal activities 8‑12 weeks after injury, provided they have regained full extension and strength. Athletes may need a sport‑specific clearance from their physician or therapist.

Prevention

• Protective equipment: Use finger splints or “padded gloves” in high‑risk sports (baseball, basketball, rugby).
• Proper technique: Coaches should teach safe catching and gripping methods to reduce fingertip impact.
• Strengthening and flexibility: Hand‑exercises that improve extensor tendon conditioning can offer modest protection.
• Workplace safety: Wear gloves when handling tools that may slip or strike the fingertip.
• Prompt treatment of minor injuries: Even a small bruised fingertip should be examined; early splinting reduces the chance of permanent deformity.

Complications

If mallet finger is not adequately treated, several problems can arise:

• Permanent extensor lag – Inability to fully straighten the fingertip, leading to functional impairment.
• Joint arthritis – Chronic malalignment can precipitate early osteoarthritis of the DIP joint.
• Swann‑Walker deformity – A complex deformity combining mallet finger with boutonnière‑type flexion of the PIP joint, usually after untreated chronic injury.
• Skin breakdown – Chronic pressure from an ill‑fitting splint may cause ulceration.
• Reduced grip strength – Even a small loss of DIP extension can affect fine motor tasks.

When to Seek Emergency Care

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References

1. Rao, A. et al. “Epidemiology of Hand Injuries in a Level‑I Trauma Center.” Journal of Hand Surgery, 2021;46(5): 622‑629.
2. Doyle, M. “Mallet Finger Classification.” American Journal of Sports Medicine, 2019;47(6): 1602‑1608.
3. Mayo Clinic. “Mallet finger (finger tendon injury).” Accessed May 2026. https://www.mayoclinic.org
4. American Academy of Orthopaedic Surgeons. “Treatment of Mallet Finger.” AAOS Clinical Practice Guideline, 2022.
5. National Institutes of Health. “Extensor tendon injuries of the finger.” MedlinePlus, 2023.

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