Arthrogryposis - observation

Historical Overview

• Arthrogryposis multiplex congenita (AMC) was first described by Otto in 1841 as congenital myodystrophy, but the term itself was not coined until 1923, when Stern used it to describe a condition found to be present in three children.^1,2
• The term “arthrogryposis” has traditionally been used to describe a variety of conditions that present with congenital joint contractures, but AMC specifically is characterized by congenital, non-progressive, and symmetric joint contractures that involve at least two different body areas, with both the upper and lower limbs usually being involved.^1,3

Description

• Patients with AMC display a number of physical and movement-related abnormalities, which can be identified during a clinical examination and used to assist in making an accurate diagnosis.

Pathophysiology

• The exact etiology of AMC is still not completely understood, but the likely cause is patchy damage of the anterior horn cells of the spinal cord in a fetus during development.^1,4
  • Any factor that decreases fetal movement may result in multiple contractures: the lack of joint mobility is associated with the development of extra connective tissue around the joints, which leads to fibrosis and contractures of the affected joints.
  • Neurological diseases, muscular and connective tissue abnormalities, limited intrauterine space, inadequate placental supply, and maternal disease, such as diabetes mellitus, myasthenia gravis, and infections may contribute to fetal akinesia and subsequent AMC.¹
• The incidence of AMC is approximately 1 in 3,000-5,000 live births, with equal gender ratio.¹
• Using the broad definition of “arthrogryposis” as any condition that presents with congenital joint contractures, more than 150 separate disease entities that share similar elements have been described.²
• Distal arthrogryposis refers to a large subgroup of disorders in which the contractures primarily involve the hands and feet. Multiple classification schemes have been used to describe these conditions, but this group is extremely heterogenous and this term does not refer to a specific disease entity.²

Instructions^1,2,4

1. Obtain an accurate and complete patient history that includes pregnancy and delivery information, family history, physical and neurological examinations, involvement of affected joints, intellectual development, and response to treatment.
2. Perform a careful examination of the entire upper extremity.
3. Observe muscle mass and strength of the hand and wrist muscles.
4. Look for the presence of flexion creases or skin dimples over large joints.
5. Passively move the fingers, hand, and wrist, taking note of any joint stiffness, and particularly focusing on thumb adduction, metacarpophalangeal (MP) or interphalangeal (IP) joint stiffness, or wrist deviation and flexion.

Related Signs and Tests¹

• Laboratory tests
  • Electrophysiological studies
  • Pathologic examinations (including muscle and/or nerve biopsy)
  • Gene sequencing 
• Prenatal screening
  • Ultrasound

• A positive result occurs when the clinician observes any of the following signs: stiffness in the fingers with varying degrees of flexion at the MP and IP joints, wrist held in flexion and ulnar deviation, thumb held in adduction, lack of flexion creases, skin dimples at large joints, reduced range of motion, and decreased muscle mass and muscle weakness

• A negative result occurs when the clinician does not observe any of the following signs: stiffness in the fingers with varying degrees of flexion at the MP and IP joints, wrist held in flexion and ulnar deviation, thumb held in adduction, lack of flexion creases, skin dimples at large joints, reduced range of motion, and decreased muscle mass and muscle weakness.

• Prenatal screening has become more widely available in recent years, but ~75% of AMC cases are not diagnosed until after delivery, and only severe AMC may be discovered by ultrasound screening.¹

1. Ma, L and Yu, X. Arthrogryposis multiplex congenita: classification, diagnosis, perioperative care, and anesthesia. Front Med 2017;11(1):48-52. PMID: 28213879
2. Ty, JM and James, MA. Failure of differentiation: Part II (arthrogryposis, camptodactyly, clinodactyly, madelung deformity, trigger finger, and trigger thumb). Hand Clin 2009;25(2):195-213. PMID: 19380060
3. Lester, R. Problems with the upper limb in arthrogryposis. J Child Orthop 2015;9(6):473-6. PMID: 26482520
4. Mennen, U, van Heest, A, Ezaki, MB, et al. Arthrogryposis multiplex congenita. J Hand Surg Br 2005;30(5):468-74. PMID: 16061316