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C&P Exam Prep: Knee Ankylosis

DC 5256 musculoskeletal 38 CFR 4.71a

DBQ Overview

Interview + Physical
Form Name
Knee_and_Lower_Leg
Form Code
Knee_and_Lower_Leg
Page Count
14
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 diagnosis, severity, and functional impact of knee joint ankylosis under DC 5256, including the specific angle of fixation which directly determines the disability rating percentage.

What the examiner evaluates:

  • Confirmation of true ankylosis versus severe limitation of motion
  • Exact angle of fixation in degrees (flexion or extension)
  • Whether ankylosis is in a favorable or unfavorable position
  • Active and passive range of motion of the affected knee
  • Weight-bearing versus non-weight-bearing ROM differences
  • Functional impact on standing, walking, sitting, climbing
  • DeLuca factors: pain, fatigue, weakness, incoordination during and after use
  • Assistive device use (cane, crutches, brace, walker, wheelchair)
  • Leg length discrepancy
  • Muscle atrophy (circumferential measurements)
  • Surgical history (TKR, meniscectomy, ligament repair)
  • Associated diagnoses and comorbidities
  • Flare-up frequency, severity, and duration

Exam will include both an interview portion and a physical examination. You will be asked to perform range of motion maneuvers while both standing (weight-bearing) and seated or lying down (non-weight-bearing). Wear loose-fitting pants or shorts. Bring all assistive devices you use. In most states you have the right to record the exam - notify the examiner at the start.

Typical duration: 30-45 minutes

Knee Flexion Range of Motion (Active)

How far you can actively bend your knee toward your buttocks; normal is 0-140 degrees

What to expect:

Examiner will ask you to bend your knee as far as possible while seated or standing. A goniometer will measure the angle. Perform this movement as you would on a typical or bad day - do not push through severe pain to demonstrate a false maximum.

Key thresholds:

  • Completely fixed (no motion) — Confirms true ankylosis; rating then determined by angle of fixation
  • Fixed at 45- or more flexion — 60% rating - extremely unfavorable position
  • Fixed between 20- and 45- flexion — 50% rating
  • Fixed between 10- and 20- flexion — 40% rating
  • Fixed in full extension (0-) or slight flexion 0-10- — 30% rating - favorable position

Tips:

  • Do not warm up or stretch the knee before the exam - arrive in your normal condition
  • If your knee locks or catches before the stated endpoint, tell the examiner immediately
  • Perform the movement at your natural pace - do not rush
  • Tell the examiner if you experience pain at any point during movement
  • If the angle is different on a bad day, describe that verbally after measurement

Pain considerations: If pain stops motion before the anatomical limit, inform the examiner: 'I'm stopping here because of pain, not because the joint won't go further.' This triggers the DeLuca pain-on-motion analysis and may entitle you to a lower (more restricted) effective ROM for rating purposes.

Knee Extension Range of Motion (Active)

How far you can actively straighten the knee; normal is 0 degrees (full extension)

What to expect:

Examiner will ask you to straighten your knee as fully as possible. A fixed knee in ankylosis typically cannot achieve this movement. Any fixed flexion contracture should be noted precisely in degrees.

Key thresholds:

  • Unable to extend (fixed flexion contracture) — Critical - confirms ankylosis; the degree of fixed flexion is the primary rating determinant
  • Extension to 0- possible — Suggests favorable ankylosis position (30%) if no true fixation, or possible limitation of motion rather than true ankylosis

Tips:

  • Report any extension lag - the difference between passive and active extension
  • If the knee feels 'locked' in flexion, describe this sensation explicitly
  • Note whether the inability to extend has worsened over time

Pain considerations: Extension attempts that are stopped by pain rather than mechanical block should be distinguished and communicated clearly to the examiner.

Passive Range of Motion

How far the examiner can move your knee without your muscular effort; reveals true joint mobility versus muscle guarding

What to expect:

Examiner will gently move your knee through flexion and extension while you relax your leg muscles completely. This is a critical measurement - if passive ROM exceeds active ROM, the examiner should note the difference and the reason (pain, weakness, incoordination).

Key thresholds:

  • Passive ROM same as active ROM — Confirms true mechanical fixation consistent with ankylosis
  • Passive ROM greater than active ROM — May suggest pain inhibition or weakness rather than true bony ankylosis - important distinction for diagnosis

Tips:

  • Relax your leg completely when examiner takes passive measurements
  • Do not resist the examiner's movement even if uncomfortable
  • Report pain, crepitus, or catching sensations during passive movement
  • True bony ankylosis will show no difference between active and passive ROM

Pain considerations: Pain during passive motion should be reported verbally: 'I feel pain when you move it there.' This is documented as evidence of pain on passive motion, a DeLuca factor.

Weight-Bearing vs. Non-Weight-Bearing ROM

Whether the angle of fixation or available motion differs when you are standing versus seated or lying down

What to expect:

Examiner should test ROM in both positions per Correia requirements. Weight-bearing testing may reveal additional functional impairment not apparent in non-weight-bearing positions.

Key thresholds:

  • Greater restriction in weight-bearing — Supports higher functional impairment; may affect rating if ROM is measured in worst position
  • Pain only with weight-bearing — Documents functional limitation beyond what seated exam shows

Tips:

  • If you can only stand for brief periods before pain increases, tell the examiner
  • If weight-bearing causes your knee to shift or buckle, report this
  • The examiner should document both positions; if they do not, politely note that you feel worse standing

Pain considerations: Standing on an ankylosed knee often produces radiating pain, altered gait mechanics, and compensatory hip/back pain - describe all of these.

Repetitive Use Testing (3 Repetitions)

Whether ROM decreases, pain increases, or fatigue develops after repeated movement attempts - core DeLuca factor

What to expect:

Examiner may ask you to perform the same knee motion three times in succession. After the third repetition, they should re-measure to see if ROM has decreased or symptoms have increased.

Key thresholds:

  • ROM decreases after repetition — Supports additional functional loss beyond initial measurement; can support higher effective disability rating
  • Pain/fatigue/weakness increases after repetition — Documents DeLuca factors - examiner should note these specifically

Tips:

  • Do not try to perform better on later repetitions - report honestly if it hurts more
  • Say explicitly: 'After doing that three times, my pain level went from a 5 to an 8'
  • If you feel your knee stiffening or weakening, say so during the test
  • After repetitions, report any increase in swelling, burning, or aching

Pain considerations: Post-repetition pain is a legitimate ratable DeLuca factor. Do not minimize it. Example: 'After bending it three times, I have a sharp burning pain on the inner side of my knee that takes about 20 minutes to calm down.'

Circumferential Thigh/Calf Muscle Atrophy Measurement

Difference in muscle circumference between the affected and unaffected leg, indicating disuse atrophy from compensating for the ankylosed knee

What to expect:

Examiner will measure around your thigh and possibly calf at a standardized point using a tape measure. Significant atrophy (>2 cm difference) documents functional disuse.

Key thresholds:

  • 2 cm or greater difference — Significant atrophy; supports additional disability, functional loss, and potential secondary conditions
  • Less than 2 cm difference — Mild or minimal atrophy; document any visible wasting regardless

Tips:

  • Do not flex your muscles during measurement - relax completely
  • If you have noticed your affected leg looks thinner or weaker, mention this proactively
  • Bring a measurement if your treating physician has documented this previously

Pain considerations: Atrophy often accompanies weakness and fatigue - describe difficulty bearing weight and how quickly the leg tires.

Leg Length Discrepancy Measurement

Whether the ankylosed knee has caused a functional or actual leg length difference that affects gait

What to expect:

Examiner measures from bony landmarks (anterior superior iliac spine to medial malleolus) on both legs. Discrepancy may result from the fixed angle of the ankylosed joint.

Key thresholds:

  • Discrepancy present — May support secondary back, hip, or gait conditions; documents additional disability
  • No discrepancy — Still document if gait is altered or if shoe lift is prescribed

Tips:

  • If you wear a shoe lift or orthotic, bring it and tell the examiner why it was prescribed
  • Mention any back or hip pain that developed after the knee became fixed
  • If you walk with a noticeable limp, describe how that has changed over time

Pain considerations: Leg length discrepancy causes compensatory mechanics that produce secondary pain - always link these to your knee ankylosis.

Estimate

Rating Criteria Breakdown

60% Knee ankylosis that is extremely unfavorable - fixed in flex ...

Knee ankylosis that is extremely unfavorable - fixed in flexion at an angle of 45 degrees or more. This position is severely functionally limiting because the knee is significantly bent and cannot support normal weight-bearing or gait.

Key Symptoms

  • Knee locked at 45- or greater flexion
  • Inability to bear full weight through the leg
  • Severe gait disturbance requiring assistive device
  • Inability to stand upright without compensatory posture
  • Extreme difficulty with sitting, standing, stairs
  • Radiating pain from compensatory hip and back mechanics
  • Wheelchair or bilateral assistive device use
  • Significant quadriceps and hamstring atrophy
  • Interference with nearly all daily activities

CFR: DC 5256: Extremely unfavorable, in flexion at an angle of 45- or more - 60%

50% Knee ankylosis fixed in flexion between 20 and 45 degrees. T ...

Knee ankylosis fixed in flexion between 20 and 45 degrees. The joint is fused in a moderately unfavorable position - functional weight-bearing is severely impaired and compensatory positioning is required.

Key Symptoms

  • Knee locked between 20-45- flexion
  • Significant alteration in gait requiring assistive device
  • Cannot stand for extended periods
  • Difficulty descending or ascending stairs
  • Secondary hip, back, or opposite knee pain from compensation
  • Use of cane, brace, or crutch
  • Moderate to severe muscle atrophy
  • Interference with prolonged sitting and standing
  • Swelling and pain around the ankylosed joint

CFR: DC 5256: In flexion between 20- and 45- - 50%

40% Knee ankylosis fixed in flexion between 10 and 20 degrees. T ...

Knee ankylosis fixed in flexion between 10 and 20 degrees. The joint is fused in a moderately unfavorable position that still significantly impairs function, particularly activities requiring knee flexion.

Key Symptoms

  • Knee locked between 10-20- flexion
  • Difficulty with activities requiring knee bend (stairs, car entry, squatting)
  • Altered gait pattern
  • Intermittent use of assistive device
  • Moderate pain with weight-bearing activities
  • Cannot run or walk on uneven terrain
  • Difficulty rising from seated position
  • Muscle weakness and fatigue with prolonged use
  • Compensatory back or hip pain

CFR: DC 5256: In flexion between 10- and 20- - 40%

30% Knee ankylosis in a favorable angle - fixed in full extensio ...

Knee ankylosis in a favorable angle - fixed in full extension (0 degrees) or slight flexion between 0 and 10 degrees. Although this is the 'best' position for ankylosis, significant functional disability remains because the knee cannot flex at all.

Key Symptoms

  • Knee locked in full extension or near-full extension (0-10- flexion)
  • Complete inability to bend knee
  • Cannot sit comfortably in standard chairs
  • Cannot climb stairs normally (must use railing and hop)
  • Difficulty getting in/out of vehicles
  • Compensatory gait pattern (circumduction)
  • Inability to kneel
  • Secondary hip, back, and opposite knee pain
  • Possible disuse atrophy despite favorable position

CFR: DC 5256: Favorable angle in full extension, or in slight flexion between 0- and 10- - 30%

How to Describe Your Symptoms

Pain

How to describe:

Describe pain by location (front of knee, behind knee, inner/outer side), character (sharp, burning, aching, throbbing), intensity on a 0-10 scale on both average days and worst days, what triggers it, what relieves it, and how long it lasts after activity.

Worst-day example:

“On my worst days, which happen at least two to three times per week, the pain starts at an 8 out of 10 just standing up from a chair. It's a deep aching pain on the inner side of my fixed knee that spreads down my shin and up into my hip. It makes me stop what I'm doing and sit for at least 30 minutes before I can move again.”

What the examiner listens for:

Specific anatomical location, numerical rating, functional triggers, duration after provocation, whether pain occurs at rest versus only with activity, and whether pain interrupts sleep.

Understatements to avoid:

Saying 'it hurts sometimes' or 'the pain isn't too bad' without quantifying. Do not minimize pain to appear tough - the examiner needs accurate information to document disability. Avoid saying 'I manage fine' if you have adapted your life around the limitation.

Functional Limitation from Ankylosis

How to describe:

Describe every specific activity the fixed knee prevents or limits: sitting in standard chairs, riding in vehicles, ascending/descending stairs, kneeling, squatting, getting up from the floor, prolonged standing, walking distance, and balance. Be concrete and specific with distances and times.

Worst-day example:

“Because my knee is locked, I cannot bend it to sit in a normal chair without my leg sticking straight out. At work I need a special chair with a leg rest, and even then after 45 minutes I have to get up and move because the pressure on my hip becomes unbearable. I can walk no more than half a block before the compensatory pain in my lower back makes me stop.”

What the examiner listens for:

Specific activities affected, adaptive strategies the veteran has adopted, distances and time tolerances, interference with work, and daily living limitations.

Understatements to avoid:

Saying 'I just avoid activities that bother it' without describing what those activities are. The examiner documents what you report - if you don't say it, it doesn't get recorded.

Fatigue and Lack of Endurance (DeLuca Factor)

How to describe:

Describe how quickly your leg fatigues with use, how the fatigue manifests (weakness, heaviness, burning), and how long recovery takes. Explain how fatigue from the ankylosed knee limits work, exercise, and daily activities.

Worst-day example:

“After walking for about 10 minutes, my thigh muscle becomes so fatigued that my whole leg feels heavy and unstable. I have to sit down for 20 to 30 minutes before I can walk again. By midday I'm exhausted from compensating with my hip and back, and I often have to lie down for an hour in the afternoon just to manage the rest of the day.”

What the examiner listens for:

Onset of fatigue relative to activity level, recovery time required, impact on occupational activities, and whether fatigue is worse on certain days.

Understatements to avoid:

Not mentioning fatigue at all because you think only pain matters. Fatigue is an explicit DeLuca factor that the examiner must document and that can increase your effective rating beyond what measured ROM alone shows.

Weakness (DeLuca Factor)

How to describe:

Describe objective weakness - difficulty lifting items with the affected leg, inability to rise from seated or squatting positions without using arms, leg giving way or buckling, and any documented muscle atrophy in your thigh.

Worst-day example:

“My quadriceps on the affected leg are noticeably smaller than the other side - my pants fit differently. I cannot push off that leg when getting up from a low chair without using both arms on the armrests. On bad days, the leg feels like it will buckle when I step off a curb.”

What the examiner listens for:

Specific functional demonstrations of weakness, documentation of atrophy, any history of falls or near-falls from the weakened leg, and occupational impact.

Understatements to avoid:

Describing weakness only vaguely as 'it feels weak.' Quantify: 'I cannot rise from a standard chair without using my arms' is far more useful than 'my leg is weak.'

Flare-Ups (DeLuca Factor)

How to describe:

Describe episodes when your condition worsens beyond baseline: frequency (times per week/month), duration (hours or days), what triggers them (weather, activity, prolonged standing), what symptoms worsen (pain, swelling, stiffness), and how flare-ups affect your ability to work and function.

Worst-day example:

“I have severe flare-ups two to three times a week, usually after any activity involving prolonged standing or when the weather changes. During a flare-up, my pain jumps to 9 out of 10, my knee and hip swell, and I am completely unable to work or perform household tasks for 24 to 48 hours. I have missed work multiple times because of these episodes.”

What the examiner listens for:

Frequency and predictability of flare-ups, what provokes them, duration of each episode, specific functional losses during flare-ups, and any documentation in medical records.

Understatements to avoid:

Describing your condition only on a typical day when the examiner asks how you are doing. Proactively volunteer flare-up information: 'Today is actually a relatively good day - on my bad days, which happen [X] times per week, the situation is significantly worse.'

Incoordination and Gait Disturbance (DeLuca Factor)

How to describe:

Describe your altered gait pattern caused by the fixed knee - swinging the leg out (circumduction), leaning to one side, inability to walk heel-to-toe, difficulty with uneven terrain, and any falls or near-falls.

Worst-day example:

“Because my knee won't bend, I have to swing my whole leg out in a circular motion to walk, which means my hip, lower back, and opposite knee take all the impact. I cannot walk on grass, gravel, or any uneven surface without serious fall risk. I have fallen twice in the past year because my fixed leg caught on something while I was walking.”

What the examiner listens for:

Observable gait abnormalities during the exam, patient-reported fall history, balance difficulties, and impact on safe ambulation in work and daily life environments.

Understatements to avoid:

Not mentioning falls or near-falls. These are critically important for documenting functional loss, safety risk, and the need for assistive devices.

Common Mistakes to Avoid

Prep Checklist

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Before Your Exam

Day Of

During the Exam

After the Exam

Your Rights During a C&P Exam

  • You have the right to request a copy of the completed DBQ after the examination - submit a written request to your VA Regional Office.
  • In most U.S. states, you have the right to record your C&P examination for personal use. Notify the examiner at the start. Check your specific state law before the appointment.
  • If the DBQ contains inaccurate or incomplete information about your symptoms, angle of fixation, or functional limitations, you have the right to submit a written rebuttal to the VA Regional Office with supporting evidence.
  • You have the right to bring a representative (VSO, attorney, claims agent) or support person to your examination. They may not speak during the exam but may be present.
  • You have the right to request a new examination if you believe the original exam was inadequate - for example, if DeLuca factors were not evaluated, ROM was not tested in both weight-bearing and non-weight-bearing positions, or the examiner was not qualified.
  • You have the right to submit a personal statement (VA Form 21-4138) describing your symptoms and functional limitations. This statement becomes part of your claims file and must be considered by the rater.
  • You are entitled to the benefit of the doubt under 38 U.S.C. - 5107(b) - if evidence is in approximate balance, the VA must resolve the doubt in your favor.
  • You have the right to request that the VA obtain your service treatment records and any federal treatment records before the examination. If these are not in your claims file, notify your VSO or submit a request.
  • Under M21-1, the examiner is required to assess DeLuca factors (pain, fatigue, weakness, incoordination, flare-ups) for all musculoskeletal conditions. If the examiner fails to address these, you have grounds to request a supplemental examination.
  • You have the right to appeal any rating decision through the Notice of Disagreement (NOD) process, Request for Higher-Level Review, or Board of Veterans' Appeals. Deadlines apply - consult a VSO or accredited claims agent immediately upon receiving an unfavorable decision.

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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.