In vivo knee kinematics will be assessed for 20 subjects that have been clinically diagnosed with substantial unicompartmental osteoarthritis (OA) by one of the surgeons of Colorado Joint Replacement; this is the location from which participants will be recruited. The objective of this study will be to analyze subjects with symptomatic unicompartmental osteoarthritis under in vivo dynamic, weight-bearing conditions using video fluoroscopy to determine if present-day OA knee braces provide separation of the femoral condyle from the tibial plateau, thus avoiding excessive loads on the degenerative compartment.

In vivo knee kinematics will be assessed for 20 subjects that have been clinically diagnosed with substantial unicompartmental osteoarthritis (OA) by one of the surgeons of Colorado Joint Replacement; this is the location from which participants will be recruited.

Enrollment will be increased to 24 subjects to account for any dropouts. Medial joint space narrowing will be clinically assessed in all patients on standing anteroposterior radiographs. The objective of this study will be to analyze subjects with symptomatic unicompartmental osteoarthritis under in vivo dynamic, weight-bearing conditions using video fluoroscopy to determine if present-day OA knee braces provide separation of the femoral condyle from the tibial plateau, thus avoiding excessive loads on the degenerative compartment.

Subjects will be asked to perform gait without the assistance of an offloading brace while under fluoroscopic evaluation. Then, each subject will be fitted with a Breg, off-the-shelf OA brace and will perform normal gait while under fluoroscopic surveillance. To ensure each brace was fitted properly, Breg will be asked to send either a sales representative or an engineer to the evaluation site. Therefore, the sales representative or engineer will be asked to fit their brace on each of the subjects.

Since the skeletal geometry is different for every person, computer aided design (CAD) models of the femur and tibia will be created for each specific subject. In order to create these CAD models, each subject will be asked to undergo a three-dimensional (3D) ultrasound using the JointVue proprietary software to reconstruct 3D femoral and tibial bones. A representative from JointVue will be present during data collection to conduct the ultrasound procedure in order to create the CAD models.

Participants will be asked to schedule a CT scan at Porter Adventist Hospital at their convenience to aid in the development of the bone models. To ensure subject safety, CT will be limited to the affected knee and the rest of patient's body will be protected from radiation with lead protection. The CT scan will be limited to the study knee and will image 6 inches distal on the tibia and 6 inches proximal on the femur.

Inclusion Criteria:

• Must be a patient of Colorado Joint Replacement.
• Must be diagnosed with marked unicompartimental degenerative joint space narrowing.
• Bilateral subjects may not be included in the subject population

Exclusion Criteria:

• Pregnant, potentially pregnant or lactating females. To satisfy radiation protocol, each female subject will be asked if she is pregnant, or possibly could be pregnant. A pregnant person will not be allowed to participate in the study.
• Subjects who are unable to perform normal walking.
• Subjects who are unwilling to sign Informed Consent/ HIPAA documents.
• Does not speak English.

Researchers would like to retain this study data in our secure database so as to continue to add relevant, current data to our digital collection to help us work with manufacturers in the future to create better implants that last longer and will not require revision surgery. Participants will be asked if their study data may remain a part of the University of Tennessee's Center for Musculoskeletal Research data collection for use in future studies in the IC. Identifiers are automatically removed from the database upon entry into the secure server. Data shared with sponsors is de-identified.