skip to main content

Acute closed central-slip extensor tendon injury of the finger — MSRA MCQ

Instant feedback + full explanation. One question, done properly.

HardSoft Tissue InjuryAcute closed central-slip extensor tendon injury of the fingerMSRA

A 30-year-old right-hand-dominant teacher attends a GP-led urgent treatment centre 4 hours after a netball struck the tip of her left middle finger. The proximal interphalangeal (PIP) joint was forcibly flexed. She has dorsal PIP swelling and focal tenderness but no wound, deformity or neurovascular deficit. She can actively extend the PIP joint almost fully, although this is painful. Passive PIP and distal interphalangeal (DIP) movement are full. True anteroposterior and lateral finger radiographs show no fracture, avulsion fragment, subluxation or dislocation. With the PIP joint flexed to 90 degrees over the edge of the examination couch, she attempts PIP extension against resistance. There is substantially reduced PIP extension force compared with the opposite hand and the DIP joint becomes rigid in extension. What is the most appropriate management today?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: B — Apply a PIP extension splint continuously, leave the DIP joint free for exercises, and arrange early hand-therapy follow-up

Explanation lettering: D = shown as A · E = shown as B · A = shown as D · B = shown as E

This is an acute closed central-slip injury. Forced PIP flexion is the typical mechanism, and normal radiographs exclude a displaced bony avulsion or fracture-dislocation requiring a different pathway. Near-full active PIP extension does not exclude central-slip rupture early after injury because the lateral bands may still provide some extension. However, the positive Elson test—reduced PIP extension force with a rigid extended DIP joint when the PIP is flexed—supports central-slip disruption. The immediate treatment is continuous splintage of the PIP joint in full extension, with early hand-therapy supervision. The DIP should remain free for prescribed active movement, helping maintain mobility while protecting the healing central slip. This reduces the risk of a fixed boutonnière deformity. A is appropriate for a stable minor collateral-ligament or volar-plate injury, not a demonstrated extensor mechanism injury. B is used for injuries requiring protection from PIP hyperextension, particularly volar-plate injuries. C treats mallet finger, in which the terminal extensor tendon at the DIP is injured. D would unnecessarily delay protective treatment: the clinical findings are diagnostic in this closed injury with normal radiographs.

Reference: Closed Central Slip Injury (Boutonniere Deformity) – Advice to patients following injury (Last updated 30 September 2025) — https://www.hey.nhs.uk/patient-leaflet/closed-central-slip-injury-boutonniere-deformity-advice-to-patients-following-injury/ Rupture of the central slip of the extensor hood of the finger. A test for early diagnosis (1986) — https://pubmed.ncbi.nlm.nih.gov/3958008/ Diagnosis of closed central slip injuries. A cadaveric analysis of non-invasive tests (1996) — https://pubmed.ncbi.nlm.nih.gov/9230945/