2026 data ClinicalTrials.gov official source

Conditions: O

Compiled by PlainTrial Editorial, Clinical Trial Intelligence Editorial Team · January 1, 2026

Every condition beginning with O that has a registered US clinical trial, with how many studies cover each.

829 conditions starting with "O"

Showing 501–550 of 829

Condition	Trials	Recruiting
Orthopedic Procedures	2	-
Orthopedic Surgery of Lower Extremity	1	-
Orthopedic Trauma Surgery Patients	1	1
Orthostatic Hypertension	1	-
Orthostatic Hypotension	17	8
Orthostatic Hypotension, Dysautonomic	2	2
Orthostatic Intolerance	6	3
Orthostatic Tachycardia	1	-
Orthostatic; Hypotension, Neurogenic	1	1
Orthostatic; Hypotension, Parkinsonism	1	1
Orthotic Device	1	-
OSA	15	6
OSA - Obstructive Sleep Apnea	1	1
OSA COPD Overlap Syndrome	1	1
OSAH	1	-
Osgood-Schlatter Syndrome (OSS)	1	-
Osseointegrated Dental Implantation	1	-
Osseointegration	2	1
Osseous Sarcoma	1	1
Osteearthritis	1	-
Osteo Arthritis Knee	23	10
Osteo Arthritis of the Knee	1	1
Osteo Arthritis Shoulders	4	3
Osteoarthitis	1	-
Osteoarthritic Knee Pain	1	1
Osteoarthritis	136	29
Osteoarthritis (OA)	2	1
Osteoarthritis (OA) of the Hip	4	3
Osteoarthritis (OA) of the Knee	9	5
Osteoarthritis (OA) of the Shoulder	2	2
Osteoarthritis - Ankle/Foot	1	1
Osteoarthritis Ankle	4	3
Osteoarthritis Foot	1	-
Osteoarthritis Hand	2	1
Osteoarthritis Knee Left	1	1
Osteoarthritis Knee Pain	2	1
Osteoarthritis Knee Right	1	1
Osteoarthritis Knees Both	1	1
Osteoarthritis of Ankle Secondary to Inflammatory Arthritis (Disorder)	1	1
Osteoarthritis of Facet Joint of Lumbar Spine	1	1
Osteoarthritis of Glenohumeral Joint	1	-
Osteoarthritis of Hip	1	1
Osteoarthritis of Knee	4	3
Osteoarthritis of Multiple Joints	1	1
Osteoarthritis of Shoulder	1	1
Osteoarthritis of the Hand	1	-
Osteoarthritis of the Hip	1	1
Osteoarthritis of the Hip or Knee	1	1
Osteoarthritis of the Knee	16	2
Osteoarthritis of the Shoulder	3	-

Data sourced from official public datasets. See our methodology for details.