Concordance Between an App-based Range of Motion Measurement and Standard Goniometer.

Inclusion Criteria: * Patient is a minimum of 18 years of age * Patient is willing and able to provide written Informed Consent by signing and dating the IRB-approved Informed Consent form Exclusion Criteria: * The patient is currently participating in any other study that would hinder the assessor's ability to measure knee ROM * Complex primary knee pathology with significant restrictions on the range of motion per surgeon discretion * Patient is pregnant or considered a member of a protected population (e.g. prisoner, mentally incompetent, etc.)