The ankle joint is stiff or locked in place, limiting its ability to move.
Medical records and physical examination findings are the most direct evidence for this condition. A VA or private examiner will measure the exact angle at which your ankle is fused and note the direction — plantar flexion or dorsiflexion — as well as any deformity such as inversion or eversion. Those measurements determine which rating level applies, so precise goniometric readings recorded in exam notes are critical.
Imaging such as X-rays can confirm that the joint is truly fused and may show bony changes or deformity that support a finding of abduction, adduction, inversion, or eversion.
If your ankle is fixed at a position near a rating boundary — for example, close to 30° or 40° of plantar flexion — multiple examination records showing consistent measurements can help establish the degree of ankylosis more clearly.
Statements from you or people who know you describing how the fixed ankle position affects walking, standing, climbing stairs, or job duties can support the overall picture, particularly where the angle of fixation places the ankle in an awkward or functionally limiting position.
Conditions that are often caused or made worse by this one. If you have any of these, they may be claimable as secondary service connection.
