Boutonniere deformity is a deformed position of the

finger A finger is a limb of the body and a type of digit, an organ of manipulation and sensation found in the hands of most of the Tetrapods, so also with humans and other primates. Most land vertebrates have five fingers ( Pentadactyly). Chambers ...

s or toes, in which the joint nearest the knuckle (the

proximal interphalangeal joint The interphalangeal joints of the hand are the hinge joints between the phalanges of the fingers that provide flexion towards the palm of the hand. There are two sets in each finger (except in the thumb, which has only one joint): * "proximal int ...

, or PIP) is permanently bent toward the palm while the farthest joint (the

distal interphalangeal joint Distal interphalangeal joints are the articulations between the phalanges of the hand or foot. This term therefore includes: * Interphalangeal joints of the hand * Interphalangeal joints of the foot The interphalangeal joints of the foot are bet ...

, or DIP) is bent back away ( PIP

flexion Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...

with DIP

hyperextension Motion, the process of movement, is described using specific anatomical terms. Motion includes movement of organs, joints, limbs, and specific sections of the body. The terminology used describes this motion according to its direction relative ...

). Causes include injury, inflammatory conditions like

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...

, and genetic conditions like Ehlers-Danlos syndrome.

Pathophysiology

This flexion

deformity A deformity, dysmorphism, or dysmorphic feature is a major abnormality of an organism that makes a part of the body appear or function differently than how it is supposed to. Causes Deformity can be caused by a variety of factors: *Arthritis an ...

of the proximal interphalangeal joint is due to interruption of the central slip of the extensor tendon such that the lateral slips separate and the head of the proximal phalanx pops through the gap like a finger through a button hole (thus the name, from French ''boutonnière'' "button hole"). The distal joint is subsequently drawn into hyperextension because the two peripheral slips of the extensor tendon are stretched by the head of the proximal phalanx (note that the two peripheral slips are inserted into the distal phalanx, while the proximal slip is inserted into the middle phalanx). This

makes it difficult or impossible to extend the proximal interphalangeal joint.

Diagnosis

Stages

# Mild extension lag, passively correctable # Moderate extension lag, passively correctable # Mild flexion contracture # Advanced flexion contracture Higher numbers indicate a more severe problem and greater likelihood of a poor outcome.

Treatment

Usually treated with a splint placing the proximal interphalangeal joint in extension for 4–6 weeks. Occasionally surgery is needed when splinting is unsuccessful.

References

External links

* {{DEFAULTSORT:Boutonniere Deformity Arthritis