Ankylosis is the immobilization or stiffness of a joint. Unfavorable finger ankylosis exists when the flexion of the finger is limited. Limitation of motion is measured by distance in terms of the gap, expressed in inches or centimeters, between the fingertips and the proximal transverse crease of the palm (wrinkle in the skin across the middle of the palm of the hand from side to side).

The condition may result from disease, trauma, surgery, contractures or, in some instances, it may be congenital.

Ankylosis of two digits of the hand would result in immobility of the fingers. However, signs and symptoms, including the degree of ankylosis, may vary due to the underlying cause or associative conditions. For example, bending may be limited and there may be deviation of the finger or fingers.

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 radiology studies.

Treatments may include: physical therapy; maintenance of the joints in a functional position; and orthopedic intervention. If the 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 process (e.g., arthritis).

Wasting away at the site of affected joints may occur due to decreased activity. The possibility of long-term rehabilitation exists.

• 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)).

• Ankylosis is the fixation or stiffness of a joint, often in an abnormal position (also referred to as arthodesis or fusion). In general, favorable ankylosis of a joint means ankylosis is fixed in a neutral position. Unfavorable ankylosis of a joint means there is fixation in flexion or extension resulting in functional impairment.

• Unfavorable finger ankylosis exists when the flexion of the finger is limited to such a degree it inhibits normal function. Limitation of motion is measured by distance in terms of the gap, expressed in inches or centimeters, between the fingertip and the proximal transverse crease of the palm (wrinkle in the skin across the middle of the palm of the hand from side to side).

• If finger flexion deformity interferes with the function of other fingers or hand function overall, assessment of the other fingers or the hand overall should be taken into account in rating. This is more appropriate than providing a higher evaluation for the ankylosed finger itself and is consistent with the requirements of 38 CFR 4.68, Amputation Rule.

• Each diagnostic code involving fingers provides for evaluation based on either major or minor handedness. Major handedness refers to the hand having dominant function or movement performance when compared to the other extremity. Handedness for the purposes of a dominant rating will be determined by the evidence of record or by testing on VA examination. Only one hand shall be considered dominant. If ambidextrous handedness is noted, the individual will be considered dominant handed for rating purposes (See 38 CFR 4.69)

• 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.

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