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C&P Exam Prep: Thumb Ankylosis
DBQ Overview
Interview + Physical- Form Name
- Hand_and_Finger
- Form Code
- Hand_and_Finger
- Page Count
- 17
- Examiner Type
- Physician or Physician Assistant
- Estimated Duration
- 30-45 minutes
- Exam Format
- Interview + Physical
What to Expect During Your Exam
Exam Overview
To document the current severity of thumb ankylosis including joint position, range of motion, functional loss, and whether ankylosis is favorable or unfavorable under 38 CFR 4.71a DC 5224, which directly determines the rating percentage assigned.
What the examiner evaluates:
- Which thumb joint(s) are ankylosed: carpometacarpal (CMC) joint, metacarpophalangeal (MCP) joint, and/or interphalangeal (IP) joint
- Whether ankylosis is favorable (10%) or unfavorable (20%)
- Gap measurement between thumb pad and fingers when attempting opposition
- Presence of angulation, rotation, or boney deformity of the ankylosed joint
- Whether both CMC and IP joints are ankylosed (may warrant amputation-equivalent rating)
- Active and passive range of motion of all thumb joints
- DeLuca factors: pain, fatigability, weakness, incoordination during repetitive use
- Functional impact on overall hand use and grip strength
- Whether other digits are affected or hand function is impaired
Exam is conducted in person. The examiner will observe hand at rest, during movement, and during grip testing. Bring any thumb splints or braces you use. You have the right to request that the exam be recorded in most states.
Typical duration: 30-45 minutes
Opposition Gap Measurement (Thumb Pad to Finger Distance)
The distance in centimeters between the thumb pad and the fingers when the veteran attempts to oppose the thumb to the fingers. This is the single most critical measurement for determining favorable vs. unfavorable ankylosis.
What to expect:
The examiner will ask you to try to bring your thumb tip toward your fingers as if pinching. They will measure the gap between your thumb pad and your fingers using a ruler or tape measure. This is done actively - you try your hardest to close the gap.
Key thresholds:
- Gap of 5.1 cm (2 inches) or less — Favorable ankylosis - supports 10% rating
- Gap greater than 5.1 cm (2 inches) — Unfavorable ankylosis - supports 20% rating
- Both CMC and IP joints ankylosed — Unfavorable regardless of gap - supports 20% or possible amputation-equivalent rating
- Angulation or rotation of bone present — May warrant amputation-equivalent rating under DC 5152
Tips:
- Attempt opposition honestly - do not force beyond your actual ability
- If you experience pain during the attempt, tell the examiner immediately
- Perform the measurement on your worst day - if you typically have more stiffness in the morning, mention this
- If the gap varies due to swelling or flare-ups, report the largest gap you typically experience
Pain considerations: Pain during opposition attempt must be reported to the examiner. Even if the gap is within 5.1 cm, pain with opposition is a significant functional limitation that should be documented. State clearly if you cannot make a full pinch effort due to pain.
Thumb CMC Joint Range of Motion (Active and Passive)
Movement at the carpometacarpal joint - the saddle joint at the base of the thumb connecting it to the wrist. Normal abduction is approximately 70 degrees; normal flexion and extension also measured.
What to expect:
The examiner will ask you to move your thumb away from your hand (abduction), flex and extend it at the base, and may attempt to move the joint passively. If ankylosed, motion will be absent or severely restricted at this joint.
Key thresholds:
- No motion at CMC joint (0 degrees) — Confirms ankylosis at CMC joint - critical for DC 5224 evaluation
- Combined CMC and IP ankylosis — Unfavorable classification - 20% or possible amputation equivalent
Tips:
- If your CMC joint is completely fused, clearly state 'I have no movement at the base of my thumb'
- Report any crepitus (grinding/clicking) you feel or hear during the attempt
- Mention whether the position of the fused joint is one that causes functional difficulty
Pain considerations: Report pain at the CMC joint at rest and with any attempted motion. Pain at rest supports documentation of constant impairment beyond simple ROM limitation.
Thumb IP Joint Range of Motion (Active and Passive)
Movement at the interphalangeal joint of the thumb - the only joint between the two thumb bones. Normal flexion is approximately 80 degrees.
What to expect:
The examiner will ask you to bend the tip of your thumb (distal phalanx). They will also attempt passive flexion if active motion is limited. Complete absence of motion confirms IP joint ankylosis.
Key thresholds:
- No motion at IP joint — Confirms IP joint ankylosis - critical for DC 5224 evaluation
- IP joint ankylosed in extension (0 degrees) or full flexion — May warrant amputation-equivalent consideration
Tips:
- If your IP joint is completely fused, do not attempt to force movement - state clearly it does not move
- Note whether the joint is fixed in a bent (flexed) or straight (extended) position
- An extended position is generally less favorable functionally
Pain considerations: Report pain at the IP joint with any attempted motion and at rest. Note whether the fixed position of the IP joint causes pain when the thumb contacts objects.
Repetitive Use / DeLuca Factors Assessment
Whether your thumb function deteriorates with repeated use - captures pain on use, fatigability, weakness, and incoordination not apparent at initial examination. Required under DeLuca v. Brown.
What to expect:
The examiner may ask you to perform repeated grip or pinch motions and assess whether symptoms worsen. They should document DeLuca factors even for ankylosed joints. If they do not ask, volunteer this information.
Key thresholds:
- Pain, weakness, or fatigability on repetitive use — Supports additional functional loss documentation beyond static ROM findings
- Incoordination affecting hand use — Supports higher functional impairment rating
Tips:
- Describe your worst day experience - not your average day or best day
- Describe specific activities you can no longer do or must modify
- Mention how long you can perform hand tasks before pain or fatigue forces you to stop
- State whether your symptoms worsen throughout the day with use
Pain considerations: Under DeLuca, the examiner must consider pain, fatigue, weakness, and incoordination as functional loss. If the examiner only records static joint position without asking about these factors, respectfully mention them yourself.
Hand Grip Strength Testing
Overall grip strength of the affected hand compared to the unaffected hand. Thumb ankylosis typically reduces grip significantly, particularly pinch strength.
What to expect:
The examiner may use a dynamometer or manual grip testing. Pinch strength (lateral pinch, tip pinch, tripod pinch) is especially relevant for thumb conditions.
Key thresholds:
- Significant grip reduction vs. contralateral hand — Documents functional impairment of hand as a whole - supports interference with overall hand function per DC 5224 Note
- Near-zero pinch strength — Supports interference with overall hand function and possible additional evaluation per DC 5224 Note
Tips:
- Grip with your maximum honest effort - do not sandbag but do not push through severe pain
- Report if grip testing causes pain or worsening of your condition
- Mention that pinch grip is more affected than power grip if that is your experience
Pain considerations: State clearly if grip testing causes pain that would limit work tasks requiring hand strength.
Rating Criteria Breakdown
| Rating % | Criteria | Key Symptoms |
|---|---|---|
| 20% | Unfavorable ankylosis of the thumb. Assigned when: (1) either the CMC or IP joint is ankylosed AND the opposition gap is greater than 5.1 cm (2 inches); OR (2) both the CMC and IP joints are ankylosed regardless of gap; OR (3) amputation at the CMC joint or through proximal phalange. A 20% rating applies to BOTH the dominant and non-dominant thumb. |
CFR: Under DC 5224: Unfavorable ankylosis is rated at 20% for both dominant and non-dominant hands. The VA note under DC 5224 also directs evaluators to consider whether amputation rating is warranted and whether additional evaluation is warranted for limitation of motion of other digits or interference with overall hand function. |
| 10% | Favorable ankylosis of the thumb. Assigned when: (1) either the CMC or IP joint is ankylosed AND the opposition gap is 5.1 cm (2 inches) or less; AND (2) only one of the two thumb joints (CMC or IP) is ankylosed, not both; AND (3) the ankylosed joint is in normal anatomical position (not angulated, rotated, or in extreme flexion or extension). A 10% rating applies to BOTH dominant and non-dominant hands. |
CFR: Under DC 5224: Favorable ankylosis is rated at 10% for both dominant and non-dominant hands. Only joints ankylosed in normal anatomical position as defined in the Note preceding DC 5216 are considered favorably ankylosed. If the fixed position is extreme, the favorable designation is lost. |
20% Unfavorable ankylosis of the thumb. Assigned when: (1) eithe ...
Unfavorable ankylosis of the thumb. Assigned when: (1) either the CMC or IP joint is ankylosed AND the opposition gap is greater than 5.1 cm (2 inches); OR (2) both the CMC and IP joints are ankylosed regardless of gap; OR (3) amputation at the CMC joint or through proximal phalange. A 20% rating applies to BOTH the dominant and non-dominant thumb.
Key Symptoms
- Opposition gap greater than 5.1 cm when attempting to touch thumb pad to fingers
- Complete stiffness at CMC or IP joint with functional thumb in poor position
- Both CMC and IP joints fused regardless of individual joint position
- Thumb cannot participate in pinch grip or appositional tasks
- Unable to grasp cylindrical objects requiring thumb wrap
- Severe limitation in activities requiring fine motor control
CFR: Under DC 5224: Unfavorable ankylosis is rated at 20% for both dominant and non-dominant hands. The VA note under DC 5224 also directs evaluators to consider whether amputation rating is warranted and whether additional evaluation is warranted for limitation of motion of other digits or interference with overall hand function.
10% Favorable ankylosis of the thumb. Assigned when: (1) either ...
Favorable ankylosis of the thumb. Assigned when: (1) either the CMC or IP joint is ankylosed AND the opposition gap is 5.1 cm (2 inches) or less; AND (2) only one of the two thumb joints (CMC or IP) is ankylosed, not both; AND (3) the ankylosed joint is in normal anatomical position (not angulated, rotated, or in extreme flexion or extension). A 10% rating applies to BOTH dominant and non-dominant hands.
Key Symptoms
- Single joint (CMC or IP) ankylosed in a functional position
- Opposition gap of 5.1 cm or less - thumb can reach close to fingers
- Residual pinch grip possible despite stiffness
- Thumb fixed in a position that allows some functional use
- Pain with use despite acceptable joint position
CFR: Under DC 5224: Favorable ankylosis is rated at 10% for both dominant and non-dominant hands. Only joints ankylosed in normal anatomical position as defined in the Note preceding DC 5216 are considered favorably ankylosed. If the fixed position is extreme, the favorable designation is lost.
How to Describe Your Symptoms
Pain
How to describe:
Describe pain at the ankylosed joint at rest, with light use, and with forceful use. Specify the character (sharp, aching, throbbing), location (base of thumb, tip joint, radiating into hand), and frequency. Distinguish between constant pain and pain triggered by activity.
Worst-day example:
“On my worst days, the base of my thumb aches constantly even when I am not using it. Any attempt to pinch - like opening a jar, turning a key, or holding a pen - causes a sharp, burning pain that makes me stop what I am doing. I cannot grip anything with my thumb for more than two or three minutes before the pain forces me to stop.”
What the examiner listens for:
Localized joint pain consistent with ankylosis, pain with opposition attempts, pain that limits functional tasks, pain that is present at rest indicating more than simple motion limitation, pain that worsens with repetitive use (DeLuca)
Understatements to avoid:
Do not say 'it is manageable' or 'I just work around it.' This underrepresents your actual limitation. Describe your worst day symptoms, not your coping mechanisms.
Functional Loss from Ankylosis
How to describe:
Explain exactly which daily tasks the fused thumb prevents or limits. Be specific: pinching, key turning, buttoning, gripping, writing, opening containers, shaking hands. Quantify how much time you can perform a task before stopping.
Worst-day example:
“Because my thumb is locked in position, I cannot pinch my fingers together to pick up small objects. I drop items constantly. I cannot button my shirt without help, cannot open pill bottles, cannot turn a key in a lock, and cannot grip a steering wheel normally. I have had to switch to adaptive tools for cooking and writing.”
What the examiner listens for:
Specific task limitations consistent with thumb opposition loss, adaptive behavior indicating compensation, impact on occupational and daily living activities, quantified limitations (time, distance, repetitions)
Understatements to avoid:
Do not describe tasks you have adapted around without noting you needed to adapt. Do not omit tasks you have simply stopped attempting entirely.
Favorable vs. Unfavorable Position
How to describe:
Describe whether your thumb's fixed position allows any functional use. If fixed in a poor position, explain how it interferes with hand function. If it creates a gap when you try to oppose fingers, estimate or demonstrate that gap.
Worst-day example:
“My thumb is frozen pointing slightly away from my hand. When I try to bring it toward my fingers to pinch something, there is a large gap - more than two inches - between my thumb and fingers. I cannot close that gap no matter how hard I try. The position makes it impossible to grip pens, coins, or buttons.”
What the examiner listens for:
Description of fixed joint position, functional consequences of that position, inability to close the opposition gap, whether the position causes contact issues or pressure points
Understatements to avoid:
Do not say 'the doctor said it healed in a good position' if in reality you have significant functional loss. Position alone does not determine functional adequacy.
Fatigability and Weakness (DeLuca Factors)
How to describe:
Describe how quickly your hand fatigues when performing tasks requiring thumb use. State your baseline grip strength versus after 5-10 minutes of use. Describe weakness that is present even on initial attempts.
Worst-day example:
“Even on a mild day, my grip is noticeably weaker on my affected hand. After just a few minutes of typing or holding a tool, my hand becomes exhausted and the weakness increases. I sometimes drop objects I thought I had a firm grip on. By the end of the day, I have almost no useful pinch strength left.”
What the examiner listens for:
Quantified weakness compared to other hand, rapid fatigability with repetitive tasks, weakness present at baseline not just after use, incoordination affecting fine motor tasks
Understatements to avoid:
Do not omit fatigue because you think it is not important for a joint that is already fused. Fatigability of surrounding muscles and tendons is a legitimate functional loss documented under DeLuca.
Flare-Ups
How to describe:
Describe frequency, duration, and severity of flare-ups if you experience them. State triggers (weather, overuse, cold), how symptoms worsen during flares, and how long recovery takes. Connect flare-up symptoms to specific functional limitations.
Worst-day example:
“About three to four times a month, my thumb and the surrounding area swells noticeably and the pain intensifies to the point where I cannot use my hand at all. These flares last two to three days. During a flare, the gap when I attempt to oppose my thumb is noticeably larger because the swelling restricts any movement even more. I cannot perform any fine motor tasks during these periods.”
What the examiner listens for:
Frequency and duration of flares, symptom intensity during flares versus baseline, whether flares cause additional functional loss beyond the ankylosed joint, triggers and recovery pattern
Understatements to avoid:
Do not describe only your average day. The DBQ specifically asks for flare-up description - ensure you provide this even if the examiner does not ask directly.
Common Mistakes to Avoid
Not demonstrating or reporting the opposition gap
The gap between thumb pad and fingers is the single most critical measurement for DC 5224. If you do not actively attempt opposition and report the gap, the examiner may default to a favorable determination.
Instead: When asked to attempt opposition, try your hardest and verbally confirm to the examiner the approximate gap you feel. If the gap is large, say so explicitly: 'I cannot get my thumb within two inches of my fingers.'
Impact: Determines 10% vs. 20% rating - worth 10 percentage points
Describing your best day rather than your worst day
M21-1 guidance and case law (e.g., Sharp v. Shinseki) establish that ratings should reflect the condition at its worst within the evaluation period. Describing your best day leads to an undervalued rating.
Instead: When asked how your thumb affects you, explicitly state 'On my worst days...' before describing symptoms. Also describe your typical day and confirm that worst days occur regularly.
Impact: All rating levels - affects whether favorable or unfavorable ankylosis is documented
Failing to mention DeLuca factors (pain, fatigue, weakness, incoordination on repetitive use)
For an ankylosed joint, examiners may focus only on joint position and ROM. However, DeLuca v. Brown requires the examiner to address functional loss from pain, fatigue, weakness, and incoordination. Omitting these results in an incomplete DBQ.
Instead: Proactively mention: 'I also experience significant pain with use, fatigue after brief activity, weakness in grip, and difficulty with coordinated fine motor tasks.' If the examiner does not document these, request that they note your statements.
Impact: All rating levels - affects functional loss documentation and potential pyramiding protections
Not reporting impact on other digits or overall hand function
The Note under DC 5224 explicitly states VA must 'also consider whether an additional evaluation is warranted for resulting limitation of motion of other digits or interference with overall function of the hand.' If you do not describe this impact, it will not be evaluated.
Instead: Describe how the ankylosed thumb affects your other fingers, your grip pattern, and your overall hand function. For example: 'Because my thumb cannot oppose, I overuse my index and long fingers to compensate, causing pain in those digits as well.'
Impact: Can unlock additional evaluations for other digits or overall hand function under DC 5224 Note
Not bringing assistive devices or adaptive equipment to the exam
If you use a thumb splint, adaptive grip tools, or other assistive devices, their presence demonstrates the severity of your condition. Their absence may allow the examiner to underestimate your functional limitation.
Instead: Bring every brace, splint, adaptive tool, or assistive device you use for your thumb or hand to the exam. Show the examiner when and why you use them.
Impact: All rating levels - affects assistive device documentation in RG_7A fields
Minimizing the functional impact because you have 'learned to work around' the condition
Compensation and adaptation are evidence of functional loss, not evidence of adequate function. Stating you have adapted can be misinterpreted as meaning the condition is less disabling.
Instead: When describing adaptations, frame them as evidence of limitation: 'I have had to switch to adaptive tools because my thumb no longer allows me to perform this task normally.' Do not omit original capabilities that you have lost.
Impact: All rating levels - affects functional impairment documentation
Not reporting whether both the CMC and IP joints are fused
If both joints are ankylosed, this automatically results in unfavorable classification regardless of the opposition gap, and may warrant an amputation-equivalent rating. Failing to confirm both joints are affected may result in a favorable determination.
Instead: Clearly state which joints are fused: 'Both the base joint of my thumb and the joint near the tip are completely fused - neither moves at all.' Confirm this with the examiner during the physical examination portion.
Impact: Determines 10% vs. 20% vs. potential amputation-equivalent rating
Prep Checklist
Before Your Exam
Day Of
During the Exam
After the Exam
Your Rights During a C&P Exam
- You have the right to have a VSO representative present during your C&P examination in most circumstances - contact your VSO in advance to arrange this.
- You have the right to request audio or video recording of your C&P examination in most states - bring a recording device and inform the examiner at the start.
- You have the right to submit a personal statement or buddy statement describing your functional limitations before or after the exam - these become part of your claims file.
- You have the right to request a copy of the completed DBQ after the examination through your VSO or via FOIA request.
- You have the right to request a new C&P examination if you believe the original exam was inadequate, incomplete, or inaccurate - document specific deficiencies in writing.
- You have the right to provide your own independent medical opinion (nexus letter or IMO) from a private physician if you disagree with the VA examiner's findings.
- You have the right to have all relevant medical evidence in your file reviewed by the examiner - if the examiner has not reviewed your service treatment records or post-service medical records, note this in writing.
- You have the right to appeal a rating decision through the Supplemental Claim, Higher Level Review, or Board of Veterans Appeals lanes if you disagree with the outcome.
- Under the benefit of the doubt standard (38 CFR 3.102), when there is an approximate balance of positive and negative evidence, VA must resolve the doubt in your favor.
- You have the right to request a pre-exam review to ensure the examiner has your complete claims file before your appointment.
Related Conditions
- Thumb Limitation of Motion If your thumb is not fully ankylosed but has limited motion, DC 5228 may apply instead of or in addition to DC 5224. Evaluate whether your condition meets ankylosis criteria or only limitation of motion criteria.
- Amputation of Thumb Under DC 5224, if both CMC and IP joints are ankylosed and either is in extension or full flexion, or if there is angulation or rotation, VA must consider rating as amputation under DC 5152. This can result in a higher evaluation than DC 5224 alone.
- Index Finger Ankylosis Under the Note to DC 5224, VA must consider whether the thumb ankylosis causes limitation of motion of other digits including the index finger. A separate evaluation under DC 5225 may be warranted if the index finger is independently affected or functionally impaired by compensatory overuse.
- Hand - Overall Functional Impairment The Note under DC 5224 directs VA to consider whether an additional evaluation is warranted for interference with overall function of the hand. If your grip strength, pinch strength, or overall hand function is significantly impaired, this may support an additional rating beyond DC 5224.
- Post-Traumatic Arthritis - Hand and Fingers If your thumb ankylosis resulted from a traumatic injury and there is residual post traumatic arthritis in the thumb joints or surrounding joints, an additional evaluation under DC 5010 (arthritis due to trauma) may be warranted.
- Degenerative Arthritis - Hand If X ray evidence demonstrates degenerative arthritis in the thumb or hand joints in addition to the ankylosis, a rating under DC 5003 may be considered for arthritis affecting minor joint groups of the hand.
- Four Digits of One Hand, Unfavorable Ankylosis If thumb ankylosis occurs in combination with ankylosis of other fingers on the same hand, multiple digit ankylosis codes (DC 5217, 5218, 5219, 5220) may apply and typically result in significantly higher combined ratings than individual digit codes.
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This C&P exam preparation guide is for educational purposes only and does not constitute legal, medical, or claims advice. Always consult with a qualified Veterans Service Organization (VSO) representative or VA-accredited attorney for guidance specific to your claim. Never exaggerate, minimize, or fabricate symptoms during a C&P examination.