Ankylosis of the index finger refers to the immobilization or stiffness of the joints of the index finger.

The condition may result from disease, trauma, surgery, or contractures due to immobility. The condition may be congenital or it may be hereditary.

Ankylosis of the index finger may result in limited motion of the index digit of the hand. The limitations will also depend on the degree of motion of the index finger. Additional signs and symptoms may be present due to the underlying cause of the condition such as, disease, trauma, surgery, or contractures.

Tests to determine the presence of ankylosis may include: inspection of the joints; palpation; measurements of range of motion (ROM); evaluation of the ligaments for stability; muscle-strength testing; sensory testing; and x-rays.

Treatments may include: physical therapy; and maintenance of the affected joints in a functional position by range of motion exercises to the affected joints. If an ankylosis was surgically created, the joint is kept immobilized in correct body alignment for 6 to 12 weeks until the bone is healed. Medications and other therapies may be instituted to treat other conditions that attribute to the condition such as arthritis (see Diagnostic Code: 5003 Arthritis, degenerative).

Residuals may include wasting away at the site of the affected joint due to decreased mobility. Physical therapy may be needed.

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• For more information, see Ankylosis or Limitation of Motion of Single or Multiple Digits of the Hand.

• For the index, long, ring, and little fingers (digits II, III, IV, and V), zero degrees of flexion represents the fingers fully extended, making a straight line with the rest of the hand. The position of function of the hand is with the wrist dorsiflexed 20 to 30 degrees, the metacarpophalangeal and proximal interphalangeal joints flexed to 30 degrees, and the thumb (digit I) abducted and rotated so that the thumb pad faces the finger pads. Only joints in these positions are considered to be in favorable position. For digits II through V, the metacarpophalangeal joint has a range of zero to 90 degrees of flexion, the proximal interphalangeal joint has a range of zero to 100 degrees of flexion, and the distal (terminal) interphalangeal joint has a range of zero to 70 or 80 degrees of flexion.

• When two or more digits of the same hand are affected by any combination of amputation, ankylosis, or limitation of motion that is not otherwise specified in the rating schedule, the evaluation level assigned will be that which best represents the overall disability (i.e., amputation, unfavorable or favorable ankylosis, or limitation of motion), assigning the higher level of evaluation when the level of disability is equally balanced between one level and the next higher level.

• Evaluation of ankylosis of the index, long, ring, and little fingers:

  • (i) If both the metacarpophalangeal and proximal interphalangeal joints of a digit are ankylosed, and either is in extension or full flexion, or there is rotation or angulation of a bone, evaluate as amputation without metacarpal resection, at proximal interphalangeal joint or proximal thereto

  • (ii) If both the metacarpophalangeal and proximal interphalangeal joints of a digit are ankylosed, evaluate as unfavorable ankylosis, even if each joint is individually fixed in a favorable position

  • (iii) If only the metacarpophalangeal or proximal interphalangeal joint is ankylosed, and there is a gap of more than two inches (5.1 cm.) between the fingertip(s) and the proximal transverse crease of the palm, with the finger(s) flexed to the extent possible, evaluate as unfavorable ankylosis

  • (iv) If only the metacarpophalangeal or proximal interphalangeal joint is ankylosed, and there is a gap of two inches (5.1 cm.) or less between the fingertip(s) and the proximal transverse crease of the palm, with the finger(s) flexed to the extent possible, evaluate as favorable ankylosis

• Evaluation of ankylosis of the thumb:

  • (i) If both the carpometacarpal and interphalangeal joints are ankylosed, and either is in extension or full flexion, or there is rotation or angulation of a bone, evaluate as amputation at metacarpophalangeal joint or through proximal phalanx

  • (ii) If both the carpometacarpal and interphalangeal joints are ankylosed, evaluate as unfavorable ankylosis, even if each joint is individually fixed in a favorable position

  • (iii) If only the carpometacarpal or interphalangeal joint is ankylosed, and there is a gap of more than two inches (5.1 cm.) between the thumb pad and the fingers, with the thumb attempting to oppose the fingers, evaluate as unfavorable ankylosis

  • (iv) If only the carpometacarpal or interphalangeal joint is ankylosed, and there is a gap of two inches (5.1 cm.) or less between the thumb pad and the fingers, with the thumb attempting to oppose the fingers, evaluate as favorable ankylosis

• Also consider whether evaluation as amputation is warranted and whether an additional evaluation is warranted for resulting limitation of motion of other digits or interference with overall function of the hand.

• For more information on Ankylosis, see the Problematic Issues section in the Musculoskeletal Overview.